Sample records for flared processing losses

  1. Reduction of Hydrocarbon Losses to Flare Systems

    E-Print Network [OSTI]

    Page, J.

    1979-01-01T23:59:59.000Z

    merit consideration because the losses and associated economic penalties are assumed to be small. Flare gas flow is not easily measured and as a result, most plants are unaware of how much product they are actually losing during normal operation...

  2. Empirical Determination of the Energy Loss Rate of Accelerated Electrons in a Well-Observed Solar Flare

    E-Print Network [OSTI]

    Piana, Michele

    Empirical Determination of the Energy Loss Rate of Accelerated Electrons in a Well-Observed Solar & Michele Piana1,3 ABSTRACT We present electron images of an extended solar flare source, deduced from the impulsive phase of a solar flare typically appears in the form of accelerated electrons. In the generally

  3. Automatic Solar Flare Tracking Using Image Processing Qu Ming and Shih Frank (shih@njit.edu)

    E-Print Network [OSTI]

    Automatic Solar Flare Tracking Using Image Processing Techniques Qu Ming and Shih Frank (shih Center for Solar-Terrestrial Research, New Jersey Institute of Technology Newark, NJ 07102 Big Bear Solar Abstract. Measurement of the evolution properties of solar flares through their complete cyclic development

  4. UNDERSTANDING THE IMPACT OF RETURN-CURRENT LOSSES ON THE X-RAY EMISSION FROM SOLAR FLARES

    SciTech Connect (OSTI)

    Holman, Gordon D., E-mail: Gordon.D.Holman@nasa.gov [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

    2012-01-20T23:59:59.000Z

    I obtain and examine the implications of one-dimensional analytic solutions for return-current losses on an initially power-law distribution of energetic electrons with a sharp low-energy cutoff in flare plasma with classical (collisional) resistivity. These solutions show, for example, that return-current losses are not sensitive to plasma density, but are sensitive to plasma temperature and the low-energy cutoff of the injected nonthermal electron distribution. A characteristic distance from the electron injection site, x{sub rc}, is derived. At distances less than x{sub rc} the electron flux density is not reduced by return-current losses, but plasma heating can be substantial in this region, in the upper, coronal part of the flare loop. Before the electrons reach the collisional thick-target region of the flare loop, an injected power-law electron distribution with a low-energy cutoff maintains that structure, but with a flat energy distribution below the cutoff energy, which is now determined by the total potential drop experienced by the electrons. Modifications due to the presence of collisional losses are discussed. I compare these results with earlier analytical results and with more recent numerical simulations. Emslie's conjecture that there is a maximum integrated X-ray source brightness on the order of 10{sup -15} photons cm{sup -2} s{sup -1} cm{sup -2} is examined. I find that this is not actually the maximum brightness and its value is parameter dependent, but it is nevertheless a valuable benchmark for identifying return-current losses in hard X-ray spectra. I discuss an observational approach to identifying return-current losses in flare data, including identification of a return-current 'bump' in X-ray light curves at low photon energies.

  5. Reducing Safety Flaring through Advanced Control

    E-Print Network [OSTI]

    Hokanson, D.; Lehman, K.; Matsumoto, S.; Takai, N.; Takase, F.

    2010-01-01T23:59:59.000Z

    An advanced process control application, using DMCplus® (Aspen Technology, Inc.), was developed to substantially reduce fuel gas losses to the flare at a large integrated refining / petrochemical complex. Fluctuations in internal fuel gas system...

  6. Diagnostics of the Heating Processes in Solar Flares Using Chromospheric Spectral Lines

    E-Print Network [OSTI]

    J. X. Cheng; M. D. Ding; J. P. Li

    2006-09-25T23:59:59.000Z

    We have calculated the H$\\alpha$ and Ca {\\sc ii} 8542 {\\AA} line profiles based on four different atmospheric models, including the effects of nonthermal electron beams with various energy fluxes. These two lines have different responses to thermal and nonthermal effects, and can be used to diagnose the thermal and nonthermal heating processes. We apply our method to an X-class flare that occurred on 2001 October 19. We are able to identify quantitatively the heating effects during the flare eruption. We find that the nonthermal effects at the outer edge of the flare ribbon are more notable than that at the inner edge, while the temperature at the inner edge seems higher. On the other hand, the results show that nonthermal effects increase rapidly in the rise phase and decrease quickly in the decay phase, but the atmospheric temperature can still keep relatively high for some time after getting to its maximum. For the two kernels that we analyze, the maximum energy fluxes of the electron beams are $\\sim$ 10$^{10}$ and 10$^{11}$ ergs cm$^{-2}$ s$^{-1}$, respectively. However, the atmospheric temperatures are not so high, i.e., lower than or slightly higher than that of the weak flare model F1 at the two kernels. We discuss the implications of the results for two-ribbon flare models.

  7. A common stochastic process rules gamma-ray burst prompt emission and X-ray flares

    E-Print Network [OSTI]

    Guidorzi, C; Frontera, F; Margutti, R; Baldeschi, A; Amati, L

    2015-01-01T23:59:59.000Z

    Prompt gamma-ray and early X-ray afterglow emission in gamma-ray bursts (GRBs) are characterized by a bursty behavior and are often interspersed with long quiescent times. There is compelling evidence that X-ray flares are linked to prompt gamma-rays. However, the physical mechanism that leads to the complex temporal distribution of gamma-ray pulses and X-ray flares is not understood. Here we show that the waiting time distribution (WTD) of pulses and flares exhibits a power-law tail extending over 4 decades with index ~2 and can be the manifestation of a common time-dependent Poisson process. This result is robust and is obtained on different catalogs. Surprisingly, GRBs with many (>=8) gamma-ray pulses are very unlikely to be accompanied by X-ray flares after the end of the prompt emission (3.1 sigma Gaussian confidence). These results are consistent with a simple interpretation: an hyperaccreting disk breaks up into one or a few groups of fragments, each of which is independently accreted with the same pro...

  8. Evolution of the Loop-Top Source of Solar Flares--Heating and Cooling Processes

    E-Print Network [OSTI]

    Yan Wei Jiang; Siming Liu; Wei Liu; Vahe Petrosian

    2005-08-24T23:59:59.000Z

    We present a study of the spatial and spectral evolution of the loop-top (LT) sources in a sample of 6 flares near the solar limb observed by {\\it RHESSI}. A distinct coronal source, which we identify as the LT source, was seen in each of these flares from the early ``pre-heating'' phase through the late decay phase. Spectral analyses reveal an evident steep power-law component in the pre-heating and impulsive phases, suggesting that the particle acceleration starts upon the onset of the flares. In the late decay phase the LT source has a thermal spectrum and appears to be confined within a small region near the top of the flare loop, and does not spread throughout the loop, as is observed at lower energies. The total energy of this source decreases usually faster than expected from the radiative cooling but much slower than that due to the classical Spitzer conductive cooling along the flare loop. These results indicate the presence of a distinct LT region, where the thermal conductivity is suppressed significantly and/or there is a continuous energy input. We suggest that plasma wave turbulence could play important roles in both heating the plasma and suppressing the conduction during the decay phase of solar flares. With a simple quasi-steady loop model we show that the energy input in the gradual phase can be comparable to that in the impulsive phase and demonstrate how the observed cooling and confinement of the LT source can be used to constrain the wave-particle interaction.

  9. Energy Loss in Nuclear Drell-Yan Process

    E-Print Network [OSTI]

    Jian-Jun Yang; Guang-Lie Li

    1998-05-21T23:59:59.000Z

    By means of the nuclear parton distributions which can be used to provide a good explanation for the EMC effect in the whole x range, we investigate the energy loss effect in nuclear Drell-Yan process. When the cross section of lepton pair production is considered varying with the center-of-mass energy of the nucleon-nucleon collision, we find that the nuclear Drell-Yan(DY) ratio is suppressed due to the energy loss, which balances the overestimate of the DY ratio only in consideration of the effect of nuclear parton distributions.

  10. EMITTING ELECTRONS SPECTRA AND ACCELERATION PROCESSES IN THE JET OF Mrk 421: FROM THE LOW STATE TO THE GIANT FLARE STATE

    SciTech Connect (OSTI)

    Yan Dahai; Zhang Li; Fan Zhonghui; Zeng Houdun [Department of Physics, Yunnan University, Kunming 650091, Yunnan (China); Yuan Qiang, E-mail: lizhang@ynu.edu.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-03-10T23:59:59.000Z

    We investigate the electron energy distributions (EEDs) and the acceleration processes in the jet of Mrk 421 through fitting the spectral energy distributions (SEDs) in different active states in the frame of a one-zone synchrotron self-Compton model. After assuming two possible EEDs formed in different acceleration models: the shock-accelerated power law with exponential cut-off (PLC) EED and the stochastic-turbulence-accelerated log-parabolic (LP) EED, we fit the observed SEDs of Mrk 421 in both low and giant flare states using the Markov Chain Monte Carlo method which constrains the model parameters in a more efficient way. The results from our calculations indicate that (1) the PLC and LP models give comparably good fits for the SED in the low state, but the variations of model parameters from low state to flaring can be reasonably explained only in the case of the PLC in the low state; and (2) the LP model gives better fits compared to the PLC model for the SED in the flare state, and the intra-day/night variability observed at GeV-TeV bands can be accommodated only in the LP model. The giant flare may be attributed to the stochastic turbulence re-acceleration of the shock-accelerated electrons in the low state. Therefore, we may conclude that shock acceleration is dominant in the low state, while stochastic turbulence acceleration is dominant in the flare state. Moreover, our result shows that the extrapolated TeV spectra from the best-fit SEDs from optical through GeV with the two EEDs are different. It should be considered with caution when such extrapolated TeV spectra are used to constrain extragalactic background light models.

  11. Method for reducing iron losses in an iron smelting process

    DOE Patents [OSTI]

    Sarma, Balu (Airmont, NY); Downing, Kenneth B. (Greenville, SC)

    1999-01-01T23:59:59.000Z

    A process of smelting iron that comprises the steps of: a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; b) maintaining conditions in said reactor to cause (i) at least some of the iron oxide to be chemically reduced, (ii) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (iii) carbon monoxide gas to rise through the slag; c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: e) keep the temperature of the molten iron at or below about 1550.degree. C. and f) keep the slag weight at or above about 0.8 tonne per square meter.

  12. Method for reducing iron losses in an iron smelting process

    DOE Patents [OSTI]

    Sarma, B.; Downing, K.B.

    1999-03-23T23:59:59.000Z

    A process of smelting iron that comprises the steps of: (a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; (b) maintaining conditions in said reactor to cause (1) at least some of the iron oxide to be chemically reduced, (2) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (3) carbon monoxide gas to rise through the slag; (c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and (d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: (1) keep the temperature of the molten iron at or below about 1550 C and (2) keep the slag weight at or above about 0.8 ton per square meter. 13 figs.

  13. Cryogenic loss monitors with FPGA TDC signal processing

    SciTech Connect (OSTI)

    Warner, A.; Wu, J.; /Fermilab

    2011-09-01T23:59:59.000Z

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highlight the processing techniques used.

  14. Hyperaccretion after the Blandford-Znajek Process: a New Model for GRBs with X-Ray Flares Observed in Early Afterglows

    E-Print Network [OSTI]

    Wei-Hua Lei; Ding-Xiong Wang; Yuan-Chuan Zou; Lei Zhang

    2008-02-04T23:59:59.000Z

    We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is powered by a rotating black hole (BH) invoking the BZ process. The second stage is a quiet stage, in which the BZ process is shut off, and the accretion onto the BH is depressed by the torque exerted by the magnetic coupling (MC) process. Part of the rotational energy transported by the MC process from the BH is stored in the disk as magnetic energy. In the third stage, the MC process is shut off when the magnetic energy in the disk accumulates and triggers the magnetic instability. At this moment, the hyperaccretion process may onset, and the jet launched in this restarted central engine generates the observed X-ray flares. This model can account for energies and timescales of GRBs with X-ray flares observed in early afterglows.

  15. OVERVIEW OF SOLAR FLARES The Yohkoh Perspective

    E-Print Network [OSTI]

    Hudson, Hugh

    that solar flares begin with high-energy processes. The key elements are accelerated particlesChapter 8 OVERVIEW OF SOLAR FLARES The Yohkoh Perspective Hugh Hudson Space Sciences Laboratory, UC of Glasgow, Glasgow G12 8QQ, Scotland, U.K. lyndsay@astro.gla.ac.uk Josef I. Khan Dept. of Physics

  16. OVERVIEW OF SOLAR FLARES The Yohkoh Perspective

    E-Print Network [OSTI]

    California at Berkeley, University of

    observations from space from the 1960s, revealed that solar flares begin with high-energy processes. The keyChapter 8 OVERVIEW OF SOLAR FLARES The Yohkoh Perspective Hugh Hudson Space Sciences Laboratory, UC of Glasgow, Glasgow G12 8QQ, Scotland, U.K. lyndsay@astro.gla.ac.uk Josef I. Khan Dept. of Physics

  17. Gel and process for preventing loss of circulation, and combination process for enhanced recovery

    SciTech Connect (OSTI)

    Sandiford, B.B.; Zillmer, R.C.

    1987-02-17T23:59:59.000Z

    A process is described for reducing the loss of circulation fluids into flow passages of a subterranean formation during well drilling, completion, or workover operations, the circulation fluids being selected from the group consisting of drilling fluids, completion fluids and workover fluids. The process comprises: (a) stopping the injection of a circulation fluid selected from the group consisting of drilling fluids, completion fluids and workover fluids into a wellbore; (b) introducing into the flow passages, an effective amount of a gel-forming composition comprising i. an aqueous solution comprising a first substance selected from the group consisting of polyvinyl alcohols, polyvinyl alcohol copolymers, and mixtures thereof, ii. an amount of an aldehyde, and iii. an amount of a crosslinking catalyzing substance, which in combination with the aqueous solution and the aldehyde is operable for effecting gelation, at the temperature of the subterranean formation, of the gel-forming composition in a period of time no greater than about 12 minutes after being introduced into the subterranean formation; and (c) allowing the gel-forming composition to enter into the flow passages and to form a gel therein within the period of time mentioned in step (b), thereby reducing the loss of the circulation fluid upon resuming well drilling, completion or workover operation.

  18. Sauget Plant Flare Gas Reduction Project

    E-Print Network [OSTI]

    Ratkowski, D. P.

    2007-01-01T23:59:59.000Z

    Empirical analysis of stack gas heating value allowed the Afton Chemical Corporation Sauget Plant to reduce natural gas flow to its process flares by about 50% while maintaining the EPA-required minimum heating value of the gas streams....

  19. Achieve smokeless flaring -- Air or steam assist?

    SciTech Connect (OSTI)

    Chaudhuri, M.; Diefenderfer, J.J.

    1995-06-01T23:59:59.000Z

    Because of the technological advances made during the past several years, flare system design has become more important with respect to the economics of plant operation. There are many options available to the engineer during the initial design phase of a flare system for a chemical process industries (CPI) plant. An earlier CEP article covered the basics of flare design and how to choose and size the right equipment, such as stack height and diameter, tip design, pilots and pilots flame detectors, seals, and so on. One of the most important factors is how to achieve smokeless operation, which is accomplished by either steam-assisted or air-assisted elevated flare stack assemblies. This article compares the two approaches and outlines the advantages and disadvantages of each with respect to economics, practicality, and operability. Table 1 summarizes the data for a typical plant in the U.S. Gulf Coast area that will be used as the basis for comparing costs.

  20. Energy Loss Effect in High Energy Nuclear Drell-Yan Process

    E-Print Network [OSTI]

    Chun-Gui Duan; Li-Hua Song; Li-Juan Huo; Guang-Lie Li

    2004-05-13T23:59:59.000Z

    The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effect on the parton distribution as in deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep inelastic scattering experimental data, measured Drell-Yan production cross sections for 800GeV proton incident on a variety of nuclear targets are analyzed within Glauber framework which takes into account energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866.

  1. Estimating Water Quality Pollution Impacts Based on Economic Loss Models in Urbanization Process

    E-Print Network [OSTI]

    Yu, Qian

    Estimating Water Quality Pollution Impacts Based on Economic Loss Models in Urbanization Process Abstract: The study investigates water quality pollution impacts on urbanization by analyzing temporal, more populations were moved from rural area into urban area, and more costs were input in water quality

  2. FLARING PATTERNS IN BLAZARS

    SciTech Connect (OSTI)

    Paggi, A.; Cavaliere, A.; Tavani, M. [Dipartimento di Fisica, Universita di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Vittorini, V.; D'Ammando, F., E-mail: paggi@roma2.infn.it [INAF/IASF-Roma, Via Fosso del Cavaliere 1, I-00100 Roma (Italy)

    2011-08-01T23:59:59.000Z

    Blazars radiate from relativistic jets launched by a supermassive black hole along our line of sight; the subclass of flat spectrum radio quasars exhibits broad emission lines, a telltale sign of a gas-rich environment and high accretion rate, contrary to the other subclass of the BL Lacertae objects. We show that this dichotomy of the sources in physical properties is enhanced in their flaring activity. The BL Lac flares yielded spectral evidence of being driven by further acceleration of highly relativistic electrons in the jet. Here, we discuss spectral fits of multi-{lambda} data concerning strong flares of the two flat spectrum radio quasars 3C 454.3 and 3C 279 recently detected in {gamma}-rays by the AGILE and Fermi satellites. We find that optimal spectral fits are provided by external Compton radiation enhanced by increasing production of thermal seed photons by growing accretion. We find such flares to trace patterns on the jet-power-electron-energy plane that diverge from those followed by flaring BL Lac objects and discuss why these occur.

  3. Recovering Flare Gas Energy - A Different Approach

    E-Print Network [OSTI]

    Brenner, W.

    Energy Technology Conference, Houston, TX, September 16-18, 1987 SLIDLIN CH81ICAL CX1'1PANY RARE GAS RECXNERY SYSID1 K.O, ~LM 19) PSIG STEAM F,D, FAN0'1 '" N Z N NAT~L GAS SEAL SEAL FU\\RE OIL PoT STACK TANK FLARE GAS I?T ~y ~LM ~LM ESL...RECOVERING FLARE GAS ENERGY - A DIFFERENT APPROACH \\ WALTER BRENNER Process Engineer SunOlin Chemical Co. Claymont, Delaware AUSTRACT Most petrochemical complexes and oil re fineries have systems to collect and dispose of waste gases...

  4. Solar Flares and particle acceleration

    E-Print Network [OSTI]

    of Glasgow, UK STFC Summer School, Armagh, 2012 #12;Solar flares: basics X-raysradiowavesParticles1AU Figure energy ~2 1032 ergs #12;"Standard" model of a solar flare/CME Solar corona T ~ 106 K => 0.1 keV per MeV Proton energies >100 MeV Large solar flare releases about 1032 ergs (about half energy

  5. Size dependence of solar X-ray flare properties

    E-Print Network [OSTI]

    Marina Battaglia; Paolo C. Grigis; Arnold O. Benz

    2005-05-09T23:59:59.000Z

    Non-thermal and thermal parameters of 85 solar flares of GOES class B1 to M6 (background subtracted classes A1 to M6) have been compared to each other. The hard X-ray flux has been measured by RHESSI and a spectral fitting provided flux and spectral index of the non-thermal emission, as well as temperature and emission measure of the thermal emission. The soft X-ray flux was taken from GOES measurements. We find a linear correlation in a double logarithmic plot between the non-thermal flux and the spectral index. The higher the acceleration rate of a flare, the harder the non-thermal electron distribution. The relation is similar to the one found by a comparison of the same parameters from several sub-peaks of a single flare. Thus small flares behave like small subpeaks of large flares. Thermal flare properties such as temperature, emission measure and the soft X-ray flux also correlate with peak non-thermal flux. A large non-thermal peak flux entails an enhancement in both thermal parameters. The relation between spectral index and the non-thermal flux is an intrinsic feature of the particle acceleration process, depending on flare size. This property affects the reported frequency distribution of flare energies.

  6. XMM-Newton Data Processing for Faint Diffuse Emission: Proton Flares, Exposure Maps and Report on EPIC MOS1 Bright CCDs Contamination

    E-Print Network [OSTI]

    J. Pradas; J. Kerp

    2005-08-04T23:59:59.000Z

    We present a study of the in-flight performance of the XMM-Newton EPIC MOS and pn detectors, with focus on the influence of proton flares and vignetting on the data. The very wide range in the conditions of our sample of observations, in terms of exposure length and background intensities, allows the detection of a wide range in the spectra of the proton flares, in contrast to the hard-spectrum flares proposed by Lumb et al.(2002) or Read et al.(2003) We also find an up to now unreported contamination in the low energy regime (E<0.5 keV) of the MOS1 observations, consisting of a significant increase in the measured intensities in two CCDs at the edges of the detector. This contamination yields in "bright CCDs" in the observations. Its effect must be taken into account for the study of sources detected in the affected CCDs. With respect to vignetting, we present in-flight exposure maps and we propose a method to repeat this calculation for user-definable energy bands. All the results presented here, have the goal to enable the study of very faint extended sources with XMM-Newton, like nearby galactic X-ray halos or the soft X-ray background.

  7. Readout process and noise elimination firmware for the Fermilab beam loss system

    SciTech Connect (OSTI)

    Wu, Jinyuan; Baumbaugh, Alan; Drennan, Craig; Thurman-Keup, Randy; Lewis, Jonathan; Shi, Zonghan; /Fermilab

    2007-05-01T23:59:59.000Z

    In the Fermilab Beam Loss Monitor System, inputs from ion chambers are integrated for a short period of time, digitized and processed to create the accelerator abort request signals. The accelerator power supplies employing 3-phase 60Hz AC cause noise at various harmonics on our inputs which must be eliminated for monitoring purposes. During accelerator ramping, both the sampling frequency and the amplitudes of the noise components change. As such, traditional digital filtering can partially reduce certain noise components but not all. A nontraditional algorithm was developed in our work to eliminate remaining ripples. The sequencing in the FPGA firmware is conducted by a micro-sequencer core we developed: the Enclosed Loop Micro-Sequencer (ELMS). The unique feature of the ELMS is that it supports the ''FOR'' loops with pre-defined iterations at the machine code level, which provides programming convenience and avoids many micro-complexities from the beginning.

  8. Soft X-ray Pulsations in Solar Flares

    E-Print Network [OSTI]

    Simões, Paulo J A; Fletcher, Lyndsay

    2014-01-01T23:59:59.000Z

    The soft X-ray emissions of solar flares come mainly from the bright coronal loops at the highest temperatures normally achieved in the flare process. Their ubiquity has led to their use as a standard measure of flare occurrence and energy, although the bulk of the total flare energy goes elsewhere. Recently Dolla et al. (2012) noted quasi-periodic pulsations (QPP) in the soft X-ray signature of the X-class flare SOL2011-02-15, as observed by the standard photometric data from the GOES (Geostationary Operational Environmental Satellite) spacecraft. We analyze the suitability of the GOES data for this kind of analysis and find them to be generally valuable after Sept. 2010 (GOES-15). We then extend Dolla et al. results to a list of X-class flares from Cycle 24, and show that most of them display QPP in the impulsive phase. During the impulsive phase the footpoints of the newly-forming flare loops may also contribute to the observed soft X-ray variations. The QPP show up cleanly in both channels of the GOES dat...

  9. PRECURSOR FLARES IN OJ 287

    SciTech Connect (OSTI)

    Pihajoki, P.; Berdyugin, A.; Lindfors, E.; Reinthal, R.; Sillanpaeae, A.; Takalo, L. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-21500 Piikkioe (Finland)] [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-21500 Piikkioe (Finland); Valtonen, M.; Nilsson, K. [Finnish Centre for Astronomy with ESO, University of Turku, FI-21500 Piikkioe (Finland)] [Finnish Centre for Astronomy with ESO, University of Turku, FI-21500 Piikkioe (Finland); Zola, S.; Koziel-Wierzbowska, D. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, PL-30-244 Krakow (Poland)] [Astronomical Observatory, Jagiellonian University, ul. Orla 171, PL-30-244 Krakow (Poland); Liakos, A. [Department of Astrophysics, Astronomy and Mechanics, University of Athens, GR 157 84 Zografos, Athens, Hellas (Greece)] [Department of Astrophysics, Astronomy and Mechanics, University of Athens, GR 157 84 Zografos, Athens, Hellas (Greece); Drozdz, M.; Winiarski, M.; Ogloza, W. [Mount Suhora Observatory, Pedagogical University, ul. Podchorazych 2, PL-30-084 Krakow (Poland)] [Mount Suhora Observatory, Pedagogical University, ul. Podchorazych 2, PL-30-084 Krakow (Poland); Provencal, J. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)] [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Santangelo, M. M. M. [O.A.C. Osservatorio Astronomico di Capannori, Via di Valle, I-55060 Vorno, Capannori (Italy)] [O.A.C. Osservatorio Astronomico di Capannori, Via di Valle, I-55060 Vorno, Capannori (Italy); Salo, H. [Department of Physical Sciences, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu (Finland)] [Department of Physical Sciences, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu (Finland); Chandra, S.; Ganesh, S.; Baliyan, K. S., E-mail: popiha@utu.fi [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India); and others

    2013-02-10T23:59:59.000Z

    We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z{sub c} = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.

  10. Flare System Optimization

    E-Print Network [OSTI]

    Aegerter, R.

    be minimally the flare manufacturer's total recommended flow. For systems with a liquid seal, the purge gas should be added downstream of the seal or designed to continuously flow through the seal at a low pressure. Excessive purge gas should not be added... problems with incorrect purge gas rates include: o Not knowing the correct purge rate o Missing restriction orifices o Improperly sized restriction orifices o Improper flow meter settings o Improperly set pressure regulators o Improper valve...

  11. Flare Gas Recovery in Shell Canada Refineries

    E-Print Network [OSTI]

    Allen, G. D.; Wey, R. E.; Chan, H. H.

    1983-01-01T23:59:59.000Z

    Two of Shell Canada's refineries have logged about six years total operating experience with modern flare gas recovery facilities. The flare gas recovery systems were designed to recover the normal continuous flare gas flow for use in the refinery...

  12. Design Enhancements To Improve Flare Efficiency

    E-Print Network [OSTI]

    Dooley, K. A.; McLeod, G. M.; Lorenz, M. D.

    Two flare systems used at separate units within a larger chemical complex were modified to improve overall performance and efficiency. One system was a standard enclosed ground flare; the other was a less-conventional horizontal ground flare system...

  13. Thermal and non-thermal energies in solar flares

    E-Print Network [OSTI]

    Pascal Saint-Hilaire; Arnold O. Benz

    2005-03-03T23:59:59.000Z

    The energy of the thermal flare plasma and the kinetic energy of the non-thermal electrons in 14 hard X-ray peaks from 9 medium-sized solar flares have been determined from RHESSI observations. The emissions have been carefully separated in the spectrum. The turnover or cutoff in the low-energy distribution of electrons has been studied by simulation and fitting, yielding a reliable lower limit to the non-thermal energy. It remains the largest contribution to the error budget. Other effects, such as albedo, non-uniform target ionization, hot target, and cross-sections on the spectrum have been studied. The errors of the thermal energy are about equally as large. They are due to the estimate of the flare volume, the assumption of the filling factor, and energy losses. Within a flare, the non-thermal/thermal ratio increases with accumulation time, as expected from loss of thermal energy due to radiative cooling or heat conduction. Our analysis suggests that the thermal and non-thermal energies are of the same magnitude. This surprising result may be interpreted by an efficient conversion of non-thermal energy to hot flare plasma.

  14. Integration of analysis and experiment for Stirling cycle processes: Part 1, Gas spring hysteresis loss

    SciTech Connect (OSTI)

    Kornhauser, A.A.; Smith, J.L. Jr.

    1988-01-01T23:59:59.000Z

    Heat transfer-related hysteresis loss can be an important factor in the performance of Stirling and other reciprocating machines. Analytical predictions of hysteresis loss have been available to designers, but until now they were not experimentally verified. Hysteresis loss was measured in a piston-cylinder gas spring over a range of speeds, pressures, gases, bore/stroke ratios, volume ratios, and internal extended surface geometries. An analysis of a simplified one-dimensional energy equation produced non-dimensional parameters that were used to correlate the experimental data. The loss expression from the analysis was adjusted to fit the correlated data. 7 refs., 8 figs.

  15. Parameterization of solar flare dose

    E-Print Network [OSTI]

    Lamarche, Anne Helene

    1995-01-01T23:59:59.000Z

    A critical aspect of missions to the Moon or Mars is the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very...

  16. Transition Region Emission and Energy Input to Thermal Plasma During the Impulsive Phase of Solar Flares

    E-Print Network [OSTI]

    J. C. Raymond; G. Holman; A. Ciaravella; A. Panasyuk; Y. -K. Ko; J. Kohl

    2007-01-12T23:59:59.000Z

    The energy released in a solar flare is partitioned between thermal and non-thermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the energy radiated at transition region temperatures during the impulsive phases of flares. We use UVCS measurements of O VI photons produced by 5 flares and subsequently scattered by O VI ions in the corona to determine the 5.0 thermal energy and the conductive losses deduced from RHESSI and GOES X-ray data using areas from RHESSI images to estimate the loop volumes, cross-sectional areas and scale lengths. The transition region luminosities during the impulsive phase exceed the X-ray luminosities for the first few minutes, but they are smaller than the rates of increase of thermal energy unless the filling factor of the X-ray emitting gas is ~ 0.01. The estimated conductive losses from the hot gas are too large to be balanced by radiative losses or heating of evaporated plasma, and we conclude that the area of the flare magnetic flux tubes is much smaller than the effective area measured by RHESSI during this phase of the flares. For the 2002 July 23 flare, the energy deposited by non-thermal particles exceeds the X-ray and UV energy losses and the rate of increase of the thermal energy.

  17. Historical Processes and Genetic Implications of Limb Reduction and Loss in an Island Skink Lineage

    E-Print Network [OSTI]

    Siler, Cameron David

    2011-12-31T23:59:59.000Z

    Evolutionary simplification, or loss of complex characters, is a major theme in studies of body form evolution. The apparently infrequent evolutionary reacquisition of complex characters has led to the assertion (Dollo's ...

  18. Return currents and energy transport in the solar flaring atmosphere

    E-Print Network [OSTI]

    Codispoti, Anna; Piana, Michele; Pinamonti, Nicola

    2013-01-01T23:59:59.000Z

    According to a standard ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated to these local currents has an ohmic nature and significantly shortens the acceleration electron path. In the present paper we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. Specifically, we show that this new formula for the energy l...

  19. "Memory loss" during mineral processing: application to base metals traceability Julie Machault (1, 2, *), Luc Barbanson (1), Thierry Aug (2), Laurent Bailly (2) et Alexandre

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    processing, target minerals, Neves Corvo. 1 Introduction The demand in mineral resources is increasing" is proposed and the relations between memory loss and global kinetic rate of flotation are established. The "global memory loss", namely as the "the experimental memory loss". For the Neves Corvo plant

  20. A SOLAR FLARE MODEL IN BETWEEN MHD AND CELLULAR AUTOMATON* Heinz Isliker1

    E-Print Network [OSTI]

    Anastasiadis, Anastasios

    and still unresolved problems in solar physics is the nature of energy release in the solar atmosphere) and the reproduction of the observed solar flare statistics. On the other hand the energy release process has been, complementary approaches (CA and MHD) for the solar flare problem. * In The Proceedings of 4th Astronomical

  1. Particle acceleration and radiation by direct electric fields in flaring complex solar active regions

    E-Print Network [OSTI]

    Anastasiadis, Anastasios

    to connect the energy re- lease process with the acceleration of electrons in solar flares, using a CA modelParticle acceleration and radiation by direct electric fields in flaring complex solar active-Meudon, 92195 Meudon Cedex, FRANCE Abstract The acceleration and radiation of solar energetic particles

  2. The mechanisms and relative importance of abiotic and biological processes for VOC loss from sludge amended soils

    SciTech Connect (OSTI)

    Wilson, S.C.; Jones, K.C. [Lancaster Univ. (United Kingdom). Inst. of Environmental and Biological Sciences

    1994-12-31T23:59:59.000Z

    The presence of volatile organic compounds (VOCs) in sewage sludge has been a cause of increasing concern due to the possible risk to human health and the environment when sludge is applied to agricultural soils. Sludge application to agricultural land in the UK is expected to increase as a result of restrictions on alternative disposal routes and also increasingly stringent wastewater treatment requirements. Few studies have examined the fate and behavior of VOCs in sewage sludge amended soils and those reported have used spiked sludge rather than investigating the behavior of VOCs resident in the sludge itself. This study was designed to evaluate the behavior of aromatic VOCs (namely toluene, xylene and ethyl benzene) in unspiked sewage sludge amended soils and assess the relative importance and mechanisms of abiotic and biological loss processes. This was undertaken by adding sewage sludge to sterilized and unsterilized soil in closed and open systems. Results indicated that abiotic loss processes, primarily volatilization, were most important for the removal of VOCs. Initial rate of VOC loss was similar in all systems. After 65 days a residual VOC soil concentration remained which was apparently dependent on the conditions within the system.

  3. Smokeless Control of Flare Steam Flow Rate

    E-Print Network [OSTI]

    Agar, J.; Balls, B. W.

    1979-01-01T23:59:59.000Z

    measurement of mass flow rate of flare gas, in spite of the hostile environment. Its use for initiating control of flare steam flow rate and the addition of molecular weight compensation, using specific gravity (relative density) measurement to achieve...

  4. Analysis of the working process and mechanical losses in a Stirling engine for a solar power unit

    SciTech Connect (OSTI)

    Makhkamov, K.K. [Uzbek Academy of Sciences, Tashkent (Uzbekistan). Physical and Technical Inst.; Ingham, D.B. [Univ. of Leeds (United Kingdom). Dept. of Applied Mathematics

    1999-05-01T23:59:59.000Z

    In this paper a second level mathematical model for the computational simulation of the working process of a 1-kW Stirling engine has been used and the results obtained are presented. The internal circuit of the engine in the calculation scheme was divided into five chambers, namely, the expansion space, heater, regenerator, cooler and the compression space, and the governing system of ordinary differential equations for the energy and mass conservation were solved in each chamber by Euler`s method. In addition, mechanical losses in the construction of the engine have been determined and the computational results show that the mechanical losses for this particular design of the Stirling engine may be up to 50% of the indicated power of the engine.

  5. Konus-Wind and Helicon-Coronas-F Observations of Solar Flares

    E-Print Network [OSTI]

    Pal'shin, V D; Aptekar, R L; Golenetskii, S V; Kokomov, A A; Svinkin, D S; Sokolova, Z Ya; Ulanov, M V; Frederiks, D D; Tsvetkova, A E

    2014-01-01T23:59:59.000Z

    Results of solar flare observations obtained in the Konus-Wind experiment from November, 1994 to December, 2013 and in the Helicon Coronas-F experiment during its operation from 2001 to 2005, are presented. For the periods indicated Konus-Wind detected in the trigger mode 834 solar flares, and Helicon-Coronas-F detected more than 300 solar flares. A description of the instruments and data processing techniques are given. As an example, the analysis of the spectral evolution of the flares SOL2012-11-08T02:19 (M 1.7) and SOL2002-03-10T01:34 (C5.1) is made with the Konus-Wind data and the flare SOL2003-10-26T06:11 (X1.2) is analyzed in the 2.223 MeV deuterium line with the Helicon-Coronas-F data.

  6. Linearly polarized X-ray flares following short gamma-ray bursts

    E-Print Network [OSTI]

    Y. Z. Fan; Bing Zhang; Daniel Proga

    2005-11-16T23:59:59.000Z

    Soft X-ray flares were detected to follow the short-duration gamma-ray burst GRB 050724. The temporal properties of the flares suggest that they are likely due to the late time activity of the central engine. We argue that if short GRBs are generated through compact star mergers, as is supported by the recent observations, the jet powering the late X-ray flares must be launched via magnetic processes rather than via neutrino-antineutrino annihilations. As a result, the X-ray flares following short GRBs are expected to be linearly polarized. The argument may also apply to the X-ray flares following long GRBs. Future observations with the upcoming X-ray polarimeters will test this prediction.

  7. Large Eddy Simulation of Industrial Flares Philip Smith

    E-Print Network [OSTI]

    Utah, University of

    At the Institute for Clean and Secure Energy at the University of Utah we are focused on education through and private industry companies to promote rapid deployment of new technologies through the use of high to solve many industrially relevant problems such as industrial flares, oxy-coal combustion processes

  8. Multi-wavelength analysis of high energy electrons in solar flares: a case study of August 20, 2002 flare

    E-Print Network [OSTI]

    J. Kasparova; M. Karlicky; E. P. Kontar; R. A. Schwartz; B. R. Dennis

    2005-08-30T23:59:59.000Z

    A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and MDI observations with advanced methods and techniques never previously applied in the solar flare context. A new method to account for X-ray Compton backscattering in the photosphere (photospheric albedo) has been used to deduce the primary X-ray flare spectra. The mean electron flux distribution has been analysed using both forward fitting and model independent inversion methods of spectral analysis. We show that the contribution of the photospheric albedo to the photon spectrum modifies the calculated mean electron flux distribution, mainly at energies below 100 keV. The positions of the Halpha emission and hard X-ray sources with respect to the current-free extrapolation of the MDI photospheric magnetic field and the characteristics of the radio emission provide evidence of the closed geometry of the magnetic field structure and the flare process in low altitude magnetic loops. In agreement with the predictions of some solar flare models, the hard X-ray sources are located on the external edges of the Halpha emission and show chromospheric plasma heated by the non-thermal electrons. The fast changes of Halpha intensities are located not only inside the hard X-ray sources, as expected if they are the signatures of the chromospheric response to the electron bombardment, but also away from them.

  9. Reorganization of visual processing in macular degeneration: Replication and clues about the role of foveal loss q

    E-Print Network [OSTI]

    Kanwisher, Nancy

    study reported reorganization fol- lowing loss of visual input as a result of optic radiation damage

  10. Magnetic reconnection configurations and particle acceleration in solar flares

    E-Print Network [OSTI]

    Chen, P. F.

    types of solar flares. Upper panel: two-ribbon flares; Lower panel: compact flares. The color shows space under different magnetic configurations. Key words: solar flares, magnetic reconnection, particleMagnetic reconnection configurations and particle acceleration in solar flares P. F. Chen, W. J

  11. RETURN CURRENTS AND ENERGY TRANSPORT IN THE SOLAR FLARING ATMOSPHERE

    SciTech Connect (OSTI)

    Codispoti, Anna; Torre, Gabriele; Piana, Michele; Pinamonti, Nicola [Dipartimento di Matematica, Universita di Genova, via Dodecaneso 35, I-16146 Genova (Italy)

    2013-08-20T23:59:59.000Z

    According to the standard Ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated with these local currents has an Ohmic nature and significantly shortens the accelerated electron path. In the present paper, we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. We show that this new formula for the energy loss rate provides a better fit of the experimental data with respect to the model based on the effects of standard Ohmic return currents.

  12. RELATION BETWEEN THE CORONAL MASS EJECTION ACCELERATION AND THE NON-THERMAL FLARE CHARACTERISTICS

    SciTech Connect (OSTI)

    Berkebile-Stoiser, S.; Veronig, A. M.; Bein, B. M.; Temmer, M., E-mail: asv@igam.uni-graz.at [Institute of Physics, University of Graz, A-8010 Graz (Austria)

    2012-07-01T23:59:59.000Z

    We investigate the relationship between the main acceleration phase of coronal mass ejections (CMEs) and the particle acceleration in the associated flares as evidenced in Reuven Ramaty High Energy Solar Spectroscopic Imager non-thermal X-rays for a set of 37 impulsive flare-CME events. Both the CME peak velocity and peak acceleration yield distinct correlations with various parameters characterizing the flare-accelerated electron spectra. The highest correlation coefficient is obtained for the relation of the CME peak velocity and the total energy in accelerated electrons (c = 0.85), supporting the idea that the acceleration of the CME and the particle acceleration in the associated flare draw their energy from a common source, probably magnetic reconnection in the current sheet behind the erupting structure. In general, the CME peak velocity shows somewhat higher correlations with the non-thermal flare parameters than the CME peak acceleration, except for the spectral index of the accelerated electron spectrum, which yields a higher correlation with the CME peak acceleration (c Almost-Equal-To -0.6), indicating that the hardness of the flare-accelerated electron spectrum is tightly coupled to the impulsive acceleration process of the rising CME structure. We also obtained high correlations between the CME initiation height h{sub 0} and the non-thermal flare parameters, with the highest correlation of h{sub 0} to the spectral index {delta} of flare-accelerated electrons (c Almost-Equal-To 0.8). This means that CMEs erupting at low coronal heights, i.e., in regions of stronger magnetic fields, are accompanied by flares that are more efficient at accelerating electrons to high energies. In the majority of events ({approx}80%), the non-thermal flare emission starts after the CME acceleration, on average delayed by Almost-Equal-To 6 minutes, in line with the standard flare model where the rising flux rope stretches the field lines underneath until magnetic reconnection sets in. We find that the current sheet length at the onset of magnetic reconnection is 21 {+-} 7 Mm. The flare hard X-ray peaks are well synchronized with the peak of the CME acceleration profile, and in 75% of the cases they occur within {+-}5 minutes. Our findings provide strong evidence for the tight coupling between the CME dynamics and the particle acceleration in the associated flare in impulsive events, with the total energy in accelerated electrons being closely correlated with the peak velocity (and thus the kinetic energy) of the CME, whereas the number of electrons accelerated to high energies is decisively related to the CME peak acceleration and the height of the pre-eruptive structure.

  13. Modeling Gamma-Ray Burst X-Ray Flares within the Internal Shock Model

    E-Print Network [OSTI]

    Maxham, Amanda

    2009-01-01T23:59:59.000Z

    X-ray afterglow light curves have been collected for over 400 Swift gamma-ray bursts with nearly half of them having X-ray flares superimposed on the regular afterglow decay. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge and spread, producing prompt emission and X-ray flares. We pay special attention to the time history of central engine activity, internal shocks, and observed flares, but do not calculate the shock dynamics and radiation processes in detail. Using the empirical E_p - E_iso (Amati) relation with an assumed Band function spectrum for each collision and an empirical flare temporal pr...

  14. Reorganization of visual processing in macular degeneration: Replication and clues about the role of foveal loss q

    E-Print Network [OSTI]

    Baker, Chris I.

    - lowing loss of visual input as a result of optic radiation damage (Dilks, Serences, Rosenau, Yantis, & Mc

  15. Quasi-periodic pulsations in solar and stellar flares: re-evaluating their nature in the context of power-law flare Fourier spectra

    E-Print Network [OSTI]

    Inglis, A R; Dominique, M

    2014-01-01T23:59:59.000Z

    The nature of quasi-periodic pulsations in solar and stellar flares remains debated. Recent work has shown that power-law-like Fourier power spectra, also referred to as 'red' noise processes, are an intrinsic property of solar and stellar flare signals, a property that many previous studies of this phenomenon have not accounted for. Hence a re-evaluation of the existing interpretations and assumptions regarding QPP is needed. Here we adopt a Bayesian method for investigating this phenomenon, fully considering the Fourier power law properties of flare signals. Using data from the PROBA2/LYRA, Fermi/GBM, Nobeyama Radioheliograph and Yohkoh/HXT instruments, we study a selection of flares from the literature identified as QPP events. Additionally we examine optical data from a recent stellar flare that appears to exhibit oscillatory properties. We find that, for all but one event tested, an explicit oscillation is not required in order to explain the observations. Instead, the flare signals are adequately descri...

  16. Magnetic Reconnection During the Two-Phase Evolution of a Solar Eruptive Flare

    E-Print Network [OSTI]

    Bhuwan Joshi; Astrid Veronig; K. -S. Cho; S. -C. Bong; Y. -J. Moon; Jeongwoo Lee; B. V. Somov; P. K. Manoharan; Y. -H. Kim

    2008-09-15T23:59:59.000Z

    We present a detailed multi-wavelength analysis and interpretation of the evolution of an M7.6 flare on October 24, 2003. The X-ray observations of the flare taken from the RHESSI spacecraft reveal two phases of the flare evolution. The first phase is characterized by the altitude decrease of the X-ray looptop (LT) source for $\\sim$11 minutes. Such a long duration of the descending LT source motion is reported for the first time. The EUV loops, located below the X-ray LT source, also undergo contraction with similar speed ($\\sim$15 km s$^{-1}$) in this interval. During the second phase the two distinct hard X-ray footpoints (FP) sources are observed which correlate well with UV and H$\\alpha$ flare ribbons. The X-ray LT source now exhibits upward motion. The RHESSI spectra during the first phase are soft and indicative of hot thermal emission from flaring loops with temperatures $T>25$ MK at the early stage. On the other hand, the spectra at high energies ($\\varepsilon \\gtrsim$25 keV) follow hard power laws during the second phase ($\\gamma = 2.6-2.8$). We show that the observed motion of the LT and FP sources can be understood as a consequence of three-dimensional magnetic reconnection at a separator in the corona. During the first phase of the flare, the reconnection releases an excess of magnetic energy related to the magnetic tensions generated before a flare by the shear flows in the photosphere. The relaxation of the associated magnetic shear in the corona by the reconnection process explains the descending motion of the LT source. During the second phase, the ordinary reconnection process dominates describing the energy release in terms of the standard model of large eruptive flares.

  17. Earth Planets Space, , , Flares and the Chromosphere

    E-Print Network [OSTI]

    Hudson, Hugh

    The radiative energy of a solar flare appears mainly in the optical and UV continuum, which form in the lowerSSL, UC Berkeley, CA USA 94720-7450 2University of Glasgow, UK (Received xxxx xx, 2003; Revised xxxx produces in the photospheric magnetic field. Key words: Solar flares, Solar chromosphere, Solar corona

  18. A MODEL FOR THE ESCAPE OF SOLAR-FLARE-ACCELERATED PARTICLES

    SciTech Connect (OSTI)

    Masson, S.; Antiochos, S. K. [Space Weather Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); DeVore, C. R., E-mail: sophie.masson@nasa.gov [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

    2013-07-10T23:59:59.000Z

    We address the problem of how particles are accelerated by solar flares can escape into the heliosphere on timescales of an hour or less. Impulsive solar energetic particle (SEP) bursts are generally observed in association with so-called eruptive flares consisting of a coronal mass ejection (CME) and a flare. These fast SEPs are believed to be accelerated directly by the flare, rather than by the CME shock. However, the precise mechanism by which the particles are accelerated remains controversial. Regardless of the origin of the acceleration, the particles should remain trapped in the closed magnetic fields of the coronal flare loops and the ejected flux rope, given the magnetic geometry of the standard eruptive-flare model. In this case, the particles would reach the Earth only after a delay of many hours to a few days (coincident with the bulk ejecta arriving at Earth). We propose that the external magnetic reconnection intrinsic to the breakout model for CME initiation can naturally account for the prompt escape of flare-accelerated energetic particles onto open interplanetary magnetic flux tubes. We present detailed 2.5-dimensional magnetohydrodynamic simulations of a breakout CME/flare event with a background isothermal solar wind. Our calculations demonstrate that if the event occurs sufficiently near a coronal-hole boundary, interchange reconnection between open and closed fields can occur. This process allows particles from deep inside the ejected flux rope to access solar wind field lines soon after eruption. We compare these results to standard observations of impulsive SEPs and discuss the implications of the model on further observations and calculations.

  19. MEASUREMENTS OF THE CORONAL ACCELERATION REGION OF A SOLAR FLARE

    SciTech Connect (OSTI)

    Krucker, Saem; Hudson, H. S.; Glesener, L.; Lin, R. P. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); White, S. M. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Masuda, S. [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Wuelser, J.-P., E-mail: krucker@ssl.berkeley.ed [Solar and Astrophysics Laboratory, Lockheed Martin ATC, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

    2010-05-10T23:59:59.000Z

    The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Nobeyama Radioheliograph (NoRH) are used to investigate coronal hard X-ray and microwave emissions in the partially disk-occulted solar flare of 2007 December 31. The STEREO mission provides EUV images of the flare site at different viewing angles, establishing a two-ribbon flare geometry and occultation heights of the RHESSI and NoRH observations of {approx}16 Mm and {approx}25 Mm, respectively. Despite the occultation, intense hard X-ray emission up to {approx}80 keV occurs during the impulsive phase from a coronal source that is also seen in microwaves. The hard X-ray and microwave source during the impulsive phase is located {approx}6 Mm above thermal flare loops seen later at the soft X-ray peak time, similar in location to the above-the-loop-top source in the Masuda flare. A single non-thermal electron population with a power-law distribution (with spectral index of {approx}3.7 from {approx}16 keV up to the MeV range) radiating in both bremsstrahlung and gyrosynchrotron emission can explain the observed hard X-ray and microwave spectrum, respectively. This clearly establishes the non-thermal nature of the above-the-loop-top source. The large hard X-ray intensity requires a very large number (>5 x 10{sup 35} above 16 keV for the derived upper limit of the ambient density of {approx}8 x 10{sup 9} cm{sup -3}) of suprathermal electrons to be present in this above-the-loop-top source. This is of the same order of magnitude as the number of ambient thermal electrons. We show that collisional losses of these accelerated electrons would heat all ambient electrons to superhot temperatures (tens of keV) within seconds. Hence, the standard scenario, with hard X-rays produced by a beam comprising the tail of a dominant thermal core plasma, does not work. Instead, all electrons in the above-the-loop-top source seem to be accelerated, suggesting that the above-the-loop-top source is itself the electron acceleration region.

  20. Effect of one-, two-, and three-body atom loss processes on superpositions of phase states in Bose-Josephson junctions

    E-Print Network [OSTI]

    Dominique Spehner; Krzysztof Pawlowski; Giulia Ferrini; Anna Minguzzi

    2014-06-26T23:59:59.000Z

    In a two-mode Bose-Josephson junction formed by a binary mixture of ultracold atoms, macroscopic superpositions of phase states are produced during the time evolution after a sudden quench to zero of the coupling amplitude. Using quantum trajectories and an exact diagonalization of the master equation, we study the effect of one-, two-, and three-body atom losses on the superpositions by analyzing separately the amount of quantum correlations in each subspace with fixed atom number. The quantum correlations useful for atom interferometry are estimated using the quantum Fisher information. We identify the choice of parameters leading to the largest Fisher information, thereby showing that, for all kinds of loss processes, quantum correlations can be partially protected from decoherence when the losses are strongly asymmetric in the two modes.

  1. Summarizing FLARE assay images in colon carcinogenesis

    E-Print Network [OSTI]

    Leyk Williams, Malgorzata

    2006-04-12T23:59:59.000Z

    usually develops slowly, the amount of oxidative damage to DNA can be used as a cancer biomarker. This dissertation examines effective ways of analyzing FLARE assay data, which quanti?es oxidative damage. The statistical methods will be implemented...

  2. Sub-GeV flashes in $?-$ray burst afterglows as probes of underlying bright UV flares

    E-Print Network [OSTI]

    Yizhong Fan; Tsvi Piran

    2006-04-17T23:59:59.000Z

    Bright optical and X-ray flares have been observed in many Gamma-ray Burst (GRB) afterglows. These flares have been attributed to late activity of the central engine. In most cases the peak energy is not known and it is possible and even likely that there is a significant far-ultraviolet component. These far-ultraviolet photons escape our detection because they are absorbed by the neutral hydrogen before reaching Earth. However, these photons cross the blast wave produced by the ejecta that have powered the initial GRB. They can be inverse Compton upscattered by hot electrons within this blast wave. This process will produce a strong sub-GeV flare that follows the high energy (soft X-ray) tail of the far-UV flare but lasts much longer and can be detected by the upcoming {\\em Gamma-Ray Large Area Telescope} (GLAST) satellite. This signature can be used to probe the spectrum of the underlying far-ultraviolet flare. The extra cooling produced by this inverse Compton process can lower the X-ray emissivity of the forward shock and explain the unexpected low early X-ray flux seen in many GRBs.

  3. Solar Flare Observations Flares are caused by the release of magnetic energy up

    E-Print Network [OSTI]

    Solar Flare Observations Flares are caused by the release of magnetic energy up to some 10 27 Joule in the solar atmosphere within a few minutes (Fig.1). The energy input causes a myriad of phenomena including of the primary energy release as electrons. Recent space missions, including Skylab, Solar Max­ imum Mission

  4. New waste-heat refrigeration unit cuts flaring, reduces pollution

    SciTech Connect (OSTI)

    Brant, B.; Brueske, S. [Planetec Utility Services Co., Inc., Evergreen, CO (United States); Erickson, D.; Papar, R. [Energy Concepts Co., Annapolis, MD (United States)

    1998-05-18T23:59:59.000Z

    Planetec Utility Services Co. Inc. and Energy Concepts Co. (ECC), with the help of the US Department of Energy (DOE), developed and commissioned a unique waste-heat powered LPG recovery plant in August 1997 at the 30,000 b/d Denver refinery, operated by Ultramar Diamond Shamrock (UDS). This new environmentally friendly technology reduces flare emissions and the loss of salable liquid-petroleum products to the fuel-gas system. The waste heat ammonia absorption refrigeration plant (Whaarp) is the first technology of its kind to use low-temperature waste heat (295 F) to achieve sub-zero refrigeration temperatures ({minus}40 F) with the capability of dual temperature loads in a refinery setting. The ammonia absorption refrigeration is applied to the refinery`s fuel-gas makeup streams to condense over 180 b/d of salable liquid hydrocarbon products. The recovered liquid, about 64,000 bbl/year of LPG and gasoline, increases annual refinery profits by nearly $1 million, while substantially reducing air pollution emissions from the refinery`s flare.

  5. Earth Planets Space, 00, 000--000, 2000 Solar Flare Mechanism Based on Magnetic Arcade

    E-Print Network [OSTI]

    Earth Planets Space, 00, 000--000, 2000 Solar Flare Mechanism Based on Magnetic Arcade Reconnection, Princeton, NJ 08543­0451 (Received ; Revised ; Accepted ) We propose a model describing physical processes is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary

  6. STATISTICS OF FLARES SWEEPING ACROSS SUNSPOTS

    SciTech Connect (OSTI)

    Li Leping; Zhang Jun, E-mail: lepingli@ourstar.bao.ac.c, E-mail: zjun@ourstar.bao.ac.c [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2009-11-20T23:59:59.000Z

    Flare ribbons are always dynamic and sometimes sweep across sunspots. After examining 588 (513 M-class and 75 X-class) flare events observed by the TRACE satellite and the Hinode/Solar Optical Telescope from 1998 May to 2009 May, we choose the event displaying one of the flare ribbons that completely sweeps across the umbra of a main sunspot of the corresponding active region, and finally obtain 20 (7 X-class and 13 M-class) events as our sample. In each event, we define the main sunspot completely swept across by the flare ribbon as the A-sunspot and its nearby opposite polarity sunspot as the B-sunspot. Observations show that the A-sunspot is a following polarity sunspot in 18 events and displays flux emergence in 13 cases. All of the B-sunspots are relatively simple, exhibiting either one main sunspot or one main sunspot and several small neighboring sunspots (pores). In two days prior to the flare occurrence, the A-sunspot rotates in all the cases, while the B-sunspot rotates in 19 events. The total rotating angle of the A-sunspot and B-sunspot rotates is 193{sup 0} on average, and the rotating directions are the same in 12 events. In all cases; the A-sunspot and B-sunspot manifest shear motions with an average shearing angle of 28.{sup 0}5, and in 14 cases, the shearing direction is opposite to the rotating direction of the A-sunspot. We suggest that the emergence, the rotation, and the shear motions of the A-sunspot and B-sunspot result in the phenomenon that flare ribbons sweep across sunspots completely.

  7. Blazar Flaring Rates Measured with GLAST

    E-Print Network [OSTI]

    Dermer, C D

    2004-01-01T23:59:59.000Z

    We derive the minimum observing time scales to detect a blazar at a given flux level with the LAT on GLAST in the scanning and pointing modes. Based upon Phase 1 observations with EGRET, we predict the GLAST detection rate of blazar flares at different flux levels. With some uncertainty given the poor statistics of bright blazars, we predict that a blazar flare with integral flux >~ 200e-8 ph(> 100 MeV) cm^{-2} s^{-1}, which are the best candidates for Target of Opportunity pointings and extensive temporal and spectral studies, should occur every few days.

  8. Blazar Flaring Rates Measured with GLAST

    E-Print Network [OSTI]

    C. D. Dermer; B. L. Dingus

    2003-12-22T23:59:59.000Z

    We derive the minimum observing time scales to detect a blazar at a given flux level with the LAT on GLAST in the scanning and pointing modes. Based upon Phase 1 observations with EGRET, we predict the GLAST detection rate of blazar flares at different flux levels. With some uncertainty given the poor statistics of bright blazars, we predict that a blazar flare with integral flux >~ 200e-8 ph(> 100 MeV) cm^{-2} s^{-1}, which are the best candidates for Target of Opportunity pointings and extensive temporal and spectral studies, should occur every few days.

  9. Approved Module Information for CE3001, 2014/5 Module Title/Name: Process Economics and Loss

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Brammer) * Capital cost estimation * Variable cost estimation * Inflation, escalation and location effects in maintaining the viability of the chemical and process industries. * The methodologies to estimate costs the effects of hazards. Knowledge and understanding * A range of cost estimation techniques * The factors

  10. Compensation of flare-induced CD changes EUVL

    DOE Patents [OSTI]

    Bjorkholm, John E. (Pleasanton, CA); Stearns, Daniel G. (Los Altos, CA); Gullikson, Eric M. (Oakland, CA); Tichenor, Daniel A. (Castro Valley, CA); Hector, Scott D. (Oakland, CA)

    2004-11-09T23:59:59.000Z

    A method for compensating for flare-induced critical dimensions (CD) changes in photolithography. Changes in the flare level results in undesirable CD changes. The method when used in extreme ultraviolet (EUV) lithography essentially eliminates the unwanted CD changes. The method is based on the recognition that the intrinsic level of flare for an EUV camera (the flare level for an isolated sub-resolution opaque dot in a bright field mask) is essentially constant over the image field. The method involves calculating the flare and its variation over the area of a patterned mask that will be imaged and then using mask biasing to largely eliminate the CD variations that the flare and its variations would otherwise cause. This method would be difficult to apply to optical or DUV lithography since the intrinsic flare for those lithographies is not constant over the image field.

  11. GRB Flares: A New Detection Algorithm, Previously Undetected Flares, and Implications on GRB Physics

    E-Print Network [OSTI]

    Swenson, C A

    2013-01-01T23:59:59.000Z

    Flares in GRB light curves have been observed since shortly after the discovery of the first GRB afterglow. However, it was not until the launch of the Swift satellite that it was realized how common flares are, appearing in nearly 50% of all X-ray afterglows as observed by the XRT instrument. The majority of these observed X-ray flares are easily distinguishable by eye and have been measured to have up to as much fluence as the original prompt emission. Through studying large numbers of these X-ray flares it has been determined that they likely result from a distinct emission source different than that powering the GRB afterglow. These findings could be confirmed if similar results were found using flares in other energy ranges. However, until now, the UVOT instrument on Swift seemed to have observed far fewer flares in the UV/optical than were seen in the X-ray. This was primarily due to poor sampling and data being spread across multiple filters, but a new optimal co-addition and normalization of the UVOT ...

  12. Magnetic changes observed in a solar flare

    SciTech Connect (OSTI)

    Moore, R.L.; Hurford, G.J.; Jones, H.P.; Kane, S.R.

    1984-01-01T23:59:59.000Z

    We present observations of a fairly large impulsive flare (1B/M4, starting 17:22 UT, 1980 April 10). Observations of the microwave/hard X-ray burst show the time development of the impulsive energy release. Chromospheric (H..cap alpha..) and photospheric (Fe I lambda5324) filtergrams and photospheric (Fe I lambda8688) magnetograms, intensitygrams, and velocitygrams show magnetic strucutre, flare emission, mass motion, and magnetic changes. From these observations, we conclude: 1. The flare was triggered by a small emerging magnetic bipole. 2. The peak impulsive energy release occurred in the explosive eruption of a filament from over the magnetic inversion line. Hence: a) The filament eruption was the magnetic transient in the heart of the primary energy release in the chromosphere and corona. b) The primary energy release did not occur in approximately stationary magnetic loops, but on field lines undergoing violet motion and drastic changes in direction. 3. In the photospheric magnetograph lines. Fe I lambda5324 and Fe I lambda8688, the impulsive peak of the flare produced emission in a unipolar area of a sunspot. In synchrony with the emission, the polarity of this area transiently reversed in the lambda8688 magnetigrams; apparently, this was an artifact of the line emission. 4. Within a few minutes after the explosive filament eruption. a) A permanent decrease in magnetic flux accompanied the truncation of an umbra. b) A permanent increase in magnetic flux accompanied the severance of the penumbral bridge to a satellite sunspot. Apparently, thee genuine photospheric magnetic changes were consequences of strong flare-wrought magnetic changes in the chromospher and corona.

  13. Interplay of Boltzmann equation and continuity equation for accelerated electrons in solar flares

    E-Print Network [OSTI]

    Codispoti, Anna

    2015-01-01T23:59:59.000Z

    During solar flares a large amount of electrons are accelerated within the plasma present in the solar atmosphere. Accurate measurements of the motion of these electrons start becoming available from the analysis of hard X-ray imaging-spectroscopy observations. In this paper, we discuss the linearized perturbations of the Boltzmann kinetic equation describing an ensemble of electrons accelerated by the energy release occurring during solar flares. Either in the limit of high energy or at vanishing background temperature such an equation reduces to a continuity equation equipped with an extra force of stochastic nature. This stochastic force is actually described by the well known energy loss rate due to Coulomb collision with ambient particles, but, in order to match the collision kernel in the linearized Boltzmann equation it needs to be treated in a very specific manner. In the second part of the paper the derived continuity equation is solved with some hyperbolic techniques, and the obtained solution is wr...

  14. WASTE INCINERATION wr090203 Activity 090203 SNAP CODE: 090203 SOURCE ACTIVITY TITLE: WASTE INCINERATION Flaring in Oil Refinery NOSE CODE: 109.03.11 NFR CODE:

    E-Print Network [OSTI]

    So Nox; Nmvoc Ch; Co Co; No Nh

    Flares are commonly used during petroleum refining for the safe disposal of waste gases during process upsets (e.g., start-up, shut-down, system blow-down) and emergencies to combust the organic content of waste emission streams without recovering/using the associated energy. 2 CONTRIBUTION TO TOTAL EMISSIONS Although flaring emission estimates are approximate, total hydrocarbon emissions from flaring at Canadian petroleum refineries during 1988 represented about 0.1 % of the refinery sector process and fugitive emissions that also included petroleum marketing emissions (CPPE, 1990). Thus the flaring operation at refineries is estimated to contribute a very small fraction of the total HC emissions in Canada. Emissions from flaring activities may also include: particulate, SOx, NOx, CO and other NMVOC. The CO2 contribution of both miscellaneous vent and flare emission sources represented approximately 9 % of the total petroleum refinery SO2 emission in Canada during 1988. Emissions estimates from flaring in petroleum refineries as reported in the CORINAIR90 inventory are summarised in Table 1. Table 1: Contribution to total emissions of the CORINAIR90 inventory (28 countries) Source-activity SNAP-code Contribution to total emissions [%

  15. Two solar flares that became X-ray plasma ejections

    E-Print Network [OSTI]

    Tomczak, Michal

    2013-01-01T23:59:59.000Z

    Solar flares and X-ray plasma ejections (XPEs) occur simultaneously but usually are separated spatially. We present two exceptional events observed by {\\sl Yohkoh} in 2001 October 2 (event 1) and 2000 October 16 (event 2), in which features of flares and XPEs are mixed. Namely, the soft and hard X-ray images show intense sources of emission that move dynamically. Both events occurred inside broad active regions showing complicated multi-level structure reaching up to 200 Mm high. Both events show also similar four-stages evolution: (1) a fast rise of a system of loops, (2) sudden changes in their emission distribution, (3) a reconfiguration leading to liberation of large amounts of plasma, (4) a small, static loop as the final remnant. Nevertheless, the events are probably caused by different physical processes: emerging magnetic flux plus reconnection (event 1) and reconnection plus ballooning instability (event 2). Different is also the final destination of the ejected plasma: in the event 1 overlying magne...

  16. Continuous and H-alpha emission of a flare of July 4, 1974

    SciTech Connect (OSTI)

    Babin, A.N.; Diatel, N.P.; Livshits, M.A.

    1985-12-01T23:59:59.000Z

    The position of a white flare is compared with those of bright nodes in the H-alpha line, as well as with the position of the neutral line of the longitudinal magnetic field. Under the assumption that the brightest knot of the white flare, adjacent to the umbra of a sunspot, does not alter its position with time, it is found that the knot coincides with the position of one of the knots of the H-alpha flare immediately before the explosive phase; subsequently, the distance between the emission maxima increases to several arc seconds. An equidensitometric analysis permitted an estimate of the energy of the event: the flux in the optical continuum exceeds the H-alpha emission by almost two orders of magnitude, while the power near the flare maximum is about 10 to the 27th erg/sec for both types of emission. The entire event is connected with the process in loops rising to heights of less than 7000 km. 18 references.

  17. TIDAL DISRUPTION FLARES: THE ACCRETION DISK PHASE

    SciTech Connect (OSTI)

    Montesinos Armijo, Matias; De Freitas Pacheco, Jose A. [Observatoire de la Cote d'Azur, Laboratoire Cassiopee, Universite de Nice Sophia-Antipolis Bd de l'Observatoire, BP 4229, 06304 Nice Cedex 4 (France)

    2011-08-01T23:59:59.000Z

    The evolution of an accretion disk, formed as a consequence of the disruption of a star by a black hole, is followed by solving numerically hydrodynamic equations. The present investigation aims to study the dependence of resulting light curves on dynamical and physical properties of such a transient disk during its existence. One of the main results derived from our simulations is that blackbody fits of X-ray data tend to overestimate the true mean disk temperature. In fact, the temperature derived from blackbody fits should be identified with the color X-ray temperature rather than the average value derived from the true temperature distribution along the disk. The time interval between the beginning of the circularization of the bound debris and the beginning of the accretion process by the black hole is determined by the viscous (or accretion) timescale, which also fixes the rising part of the resulting light curve. The luminosity peak coincides with the beginning of matter accretion by the black hole and the late evolution of the light curve depends on the evolution of the debris fallback rate. Peak bolometric luminosities are in the range 10{sup 45}-10{sup 46} erg s{sup -1}, whereas peak luminosities in soft X-rays (0.2-2.0 keV) are typically one order of magnitude lower. The typical timescale derived from our preferred models for the flare luminosity to decay by two orders of magnitude is about 3-4 yr. Predicted soft X-ray light curves reproduce quite well data on galaxies in which a variable X-ray emission possibly related to a tidal event was detected. In the cases of NGC 3599 and IC 3599, data are reproduced well by models defined by a black hole with mass {approx}10{sup 7} M{sub sun} and a disrupted star of about 1 solar mass. The X-ray variation observed in XMMSL1 is consistent with a model defined by a black hole with mass {approx}3 x 10{sup 6} M{sub sun} and a disrupted star of 1 solar mass, while that observed in the galaxy situated in the cluster A1689 is consistent with a model including a black hole of {approx}10{sup 7} M{sub sun} and a disrupted star of {approx}0.5 M{sub sun}.

  18. Flares in GRB afterglows from delayed magnetic dissipation

    E-Print Network [OSTI]

    Dimitrios Giannios

    2006-06-19T23:59:59.000Z

    One of the most intriguing discoveries made by the Swift satellite is the flaring activity in about half of the afterglow lightcurves. Flares have been observed on both long and short duration GRBs and on time scales that range from minutes to ~1 day after the prompt emission. The rapid evolution of some flares led to the suggestion that they are caused by late central engine activity. Here, I propose an alternative explanation that does not need reviving of the central engine. Flares can be powered by delayed magnetic dissipation in strongly magnetized (i.e. with initial Poynting to kinetic flux ratio $\\simmore 1$) ejecta during its deceleration due to interaction with the external medium. A closer look at the length scales of the dissipation regions shows that magnetic dissipation can give rise to fast evolving and energetic flares. Multiple flares are also expected in the context of the model.

  19. A Statistical Solar Flare Forecast Method

    E-Print Network [OSTI]

    M. S. Wheatland

    2005-05-14T23:59:59.000Z

    A Bayesian approach to solar flare prediction has been developed, which uses only the event statistics of flares already observed. The method is simple, objective, and makes few ad hoc assumptions. It is argued that this approach should be used to provide a baseline prediction for certain space weather purposes, upon which other methods, incorporating additional information, can improve. A practical implementation of the method for whole-Sun prediction of Geostationary Observational Environment Satellite (GOES) events is described in detail, and is demonstrated for 4 November 2003, the day of the largest recorded GOES flare. A test of the method is described based on the historical record of GOES events (1975-2003), and a detailed comparison is made with US National Oceanic and Atmospheric Administration (NOAA) predictions for 1987-2003. Although the NOAA forecasts incorporate a variety of other information, the present method out-performs the NOAA method in predicting mean numbers of event days, for both M-X and X events. Skill scores and other measures show that the present method is slightly less accurate at predicting M-X events than the NOAA method, but substantially more accurate at predicting X events, which are important contributors to space weather.

  20. X-ray Flares in Gamma-Ray Bursts.

    E-Print Network [OSTI]

    Morris, David

    2008-01-01T23:59:59.000Z

    ??Data from the Swift mission have now shown that flares are a common component of Gamma-Ray Burst afterglows, appearing in roughly 50% of GRBs to… (more)

  1. Magnetic Flares and State Transitions in Galactic Black Hole and Neutron Star Systems

    E-Print Network [OSTI]

    Sergei Nayakshin; Fulvio Melia

    1997-10-21T23:59:59.000Z

    We here examine the conditions of the two-phase disk model under which magnetic flares arise above the cold accretion disk due to magnetic buoyancy and produce X-rays via Comptonization of the disk's soft radiation. We find that the disk's ability to produce strong magnetic flares is substantially diminished in its radiation dominated regions due to the diffusion of radiation into the magnetic flux tubes. Using a simplified, yet physically self-consistent, model that takes this effect into account, we show that the hard X-ray spectrum of some GBHCs can be explained as the X-ray emission by magnetic flares only when the disk's bolometric luminosity is a relatively small fraction ($\\sim$ 5%) of the Eddington value, $L_{Edd}$. Further, we compute the hard ($20-200$ keV) and soft ($1-20$ keV) X-ray power as a function of the disk's luminosity, and find an excellent agreement with the available data for GBHC transient and persistent sources. We conclude that the observed high-energy spectrum of stellar-sized accretion disk systems can be explained by Comptonization of the disk's soft radiation by the hot gas trapped inside the magnetic flares when the luminosity falls in the range $\\sim 10^{-3}-10^{-1}\\times L_{Edd}$. For higher luminosities, another emission mechanism must be at work. For lower luminosities, the X-ray emissivity may still be dominated by magnetic flares, but this process is more likely to be thermal or non-thermal bremstrahlung, so that the X-ray spectrum below $\\sim 10^{-3}L_{Edd}$ may be quite distinct from the typical hard spectrum for higher luminosities.

  2. Natural Gas Vented and Flared

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia,(Million Barrels) Crude Oil Reserves in Nonproducing ReservoirsYear-Month Week 1 Week 2 Week 3Processing:Used

  3. Relationships between physical and observational parameters during flares on

    E-Print Network [OSTI]

    Complutense de Madrid, Universidad

    for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. 3 Armagh Observatory, College Hill, Armagh BT61 9DG 2200 AG Noordwijk, The Netherlands. Summary. A great number of short and weak non white-light flares Solar flares were discovered by Carrington and Hodgson on September 1, 1859 [2, 19]. However

  4. IMPLICATIONS OF MASS AND ENERGY LOSS DUE TO CORONAL MASS EJECTIONS ON MAGNETICALLY ACTIVE STARS

    SciTech Connect (OSTI)

    Drake, Jeremy J.; Cohen, Ofer [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yashiro, Seiji [Interferometrics Inc., Herndon, VA 20171 (United States)] [Interferometrics Inc., Herndon, VA 20171 (United States); Gopalswamy, Nat, E-mail: jdrake@cfa.harvard.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-02-20T23:59:59.000Z

    Analysis of a database of solar coronal mass ejections (CMEs) and associated flares over the period 1996-2007 finds well-behaved power-law relationships between the 1-8 A flare X-ray fluence and CME mass and kinetic energy. We extrapolate these relationships to lower and higher flare energies to estimate the mass and energy loss due to CMEs from stellar coronae, assuming that the observed X-ray emission of the latter is dominated by flares with a frequency as a function of energy dn/dE = kE {sup -{alpha}}. For solar-like stars at saturated levels of X-ray activity, the implied losses depend fairly weakly on the assumed value of {alpha} and are very large: M-dot {approx}5 Multiplication-Sign 10{sup -10} M{sub sun} yr{sup -1} and E-dot {approx}0.1 L{sub sun}. In order to avoid such large energy requirements, either the relationships between CME mass and speed and flare energy must flatten for X-ray fluence {approx}> 10{sup 31} erg, or the flare-CME association must drop significantly below 1 for more energetic events. If active coronae are dominated by flares, then the total coronal energy budget is likely to be up to an order of magnitude larger than the canonical 10{sup -3} L {sub bol} X-ray saturation threshold. This raises the question of what is the maximum energy a magnetic dynamo can extract from a star? For an energy budget of 1% of L {sub bol}, the CME mass loss rate is about 5 Multiplication-Sign 10{sup -11} M {sub Sun} yr{sup -1}.

  5. EVIDENCE FOR HOT FAST FLOW ABOVE A SOLAR FLARE ARCADE

    SciTech Connect (OSTI)

    Imada, S. [Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)] [Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Aoki, K.; Hara, H.; Watanabe, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan); Harra, L. K. [UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)] [UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Shimizu, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara-shi, Kanagawa 229-8510 (Japan)] [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara-shi, Kanagawa 229-8510 (Japan)

    2013-10-10T23:59:59.000Z

    Solar flares are one of the main forces behind space weather events. However, the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in the corona where hot fast flows are created. Some imaging or spectroscopic observations have indicated the presence of these hot fast flows, but there have been no spectroscopic scanning observations to date to measure the two-dimensional structure quantitatively. We analyzed a flare that occurred on the west solar limb on 2012 January 27 observed by the Hinode EUV Imaging Spectrometer (EIS) and found that the hot (?30MK) fast (>500 km s{sup –1}) component was located above the flare loop. This is consistent with magnetic reconnection taking place above the flare loop.

  6. A BLAZAR-LIKE RADIO FLARE IN MRK 231

    SciTech Connect (OSTI)

    Reynolds, Cormac; Hurley-Walker, Natasha [ICRAR-Curtin University, GPO Box U1987, Perth, Western Australia, 6102 (Australia)] [ICRAR-Curtin University, GPO Box U1987, Perth, Western Australia, 6102 (Australia); Punsly, Brian [1415 Granvia Altamira, Palos Verdes Estates, CA 90274 (United States)] [1415 Granvia Altamira, Palos Verdes Estates, CA 90274 (United States); O'Dea, Christopher P., E-mail: brian.punsly1@verizon.net, E-mail: brian.punsly@comdev-usa.com [Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2013-10-20T23:59:59.000Z

    Radio monitoring of the broad absorption line quasar (BALQSO) Mrk 231 from 13.9 GHz to 17.6 GHz detected a strong flat spectrum flare. Even though BALQSOs are typically weak radio sources, the 17.6 GHz flux density doubled in ?150 days, from ?135 mJy to ?270 mJy. It is demonstrated that the elapsed rise time in the quasar rest frame and the relative magnitude of the flare is typical of some of the stronger flares in blazars that are usually associated with the ejection of discrete components on parsec scales. The decay of a similar flare was found in a previous monitoring campaign at 22 GHz. We conclude that these flares are not rare. The implication is that Mrk 231 seems to be a quasar in which the physical mechanism that produces the broad absorption line wind is in tension with the emergence of a fledgling blazar.

  7. Xray Flare Light Curves and Dimensions of the Flaring S. Serio, F. Reale, R. Betta, G. Peres

    E-Print Network [OSTI]

    the temperature evolution as tracer of the presence of heating during the decay. Many solar flares appear). We outline here the method and some testing on spatially­resolved solar flares observed with Yohkoh (slope in a Log/Log plot) depends on the decay time of the heating re­ leased in the loop during

  8. 36Super-fast solar flares ! NASA's Ramaty High Energy Solar

    E-Print Network [OSTI]

    36Super-fast solar flares ! NASA's Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite has been studying solar flares since 2002. The sequence of figures to the left shows a flaring region hr/3600 sec = 0.98 kilometers/sec. The solar flare blob was traveling at 207 kilometers per second

  9. Solar Flare Measurements with STIX and MiSolFA

    E-Print Network [OSTI]

    Casadei, Diego

    2014-01-01T23:59:59.000Z

    Solar flares are the most powerful events in the solar system and the brightest sources of X-rays, often associated with emission of particles reaching the Earth and causing geomagnetic storms, giving problems to communication, airplanes and even black-outs. X-rays emitted by accelerated electrons are the most direct probe of solar flare phenomena. The Micro Solar-Flare Apparatus (MiSolFA) is a proposed compact X-ray detector which will address the two biggest issues in solar flare modeling. Dynamic range limitations prevent simultaneous spectroscopy with a single instrument of all X-ray emitting regions of a flare. In addition, most X-ray observations so far are inconsistent with the high anisotropy predicted by the models usually adopted for solar flares. Operated at the same time as the STIX instrument of the ESA Solar Orbiter mission, at the next solar maximum (2020), they will have the unique opportunity to look at the same flare from two different directions: Solar Orbiter gets very close to the Sun wit...

  10. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT

    SciTech Connect (OSTI)

    Warren, Harry P.; Doschek, George A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Mariska, John T. [School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2013-06-20T23:59:59.000Z

    One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.

  11. Evaluating Transformer Losses

    E-Print Network [OSTI]

    Grun, R. L. Jr.

    and replacing them with low loss units. Today few industrials evaluate losses on either power or distribution transformers. TRANSFORMER LOSSES Transformer losses are divided 'nto load losses and no-load losses. Load losses are due to the winding resista... therefore are a function of the load squared. No-load losses occur from energizing the transformer steel and fore are continuous regardless of the transformer load. TRANSFORMER DESIGN Both types of losses are a fun ce here ion of design. If losses...

  12. Sign singularity and flares in solar active region NOAA 11158

    E-Print Network [OSTI]

    Sorriso-Valvo, Luca; Kazachenko, Maria D; Krucker, Sam; Primavera, Leonardo; Servidio, Sergio; Vecchio, Antonio; Welsch, Brian T; Fisher, George H; Lepreti, Fabio; Carbone, Vincenzo

    2015-01-01T23:59:59.000Z

    Solar Active Region NOAA 11158 has hosted a number of strong flares, including one X2.2 event. The complexity of current density and current helicity are studied through cancellation analysis of their sign-singular measure, which features power-law scaling. Spectral analysis is also performed, revealing the presence of two separate scaling ranges with different spectral index. The time evolution of parameters is discussed. Sudden changes of the cancellation exponents at the time of large flares, and the presence of correlation with EUV and X-ray flux, suggest that eruption of large flares can be linked to the small scale properties of the current structures.

  13. Sub-GeV flashes in $\\gamma-$ray burst afterglows as probes of underlying bright UV flares

    E-Print Network [OSTI]

    Fan, Y; Fan, Yizhong; Piran, Tsvi

    2006-01-01T23:59:59.000Z

    Bright optical and X-ray flares have been observed in many Gamma-ray Burst (GRB) afterglows. These flares have been attributed to late activity of the central engine. In most cases the peak energy is not known and it is possible and even likely that there is a significant far-ultraviolet component. These far-UV photons escape our detection because they are absorbed by the neutral hydrogen before reaching Earth. However, these photons cross the blast wave produced by the ejecta that have powered the initial GRB. They can be inverse Compton upscattered by hot electrons within this blast wave. This process will produce a strong sub-GeV flare that can be detected by the upcoming {\\em Gamma-Ray Large Area Telescope} (GLAST) satellite. This signature can be used to probe the spectrum of the underlying far-ultraviolet flare. The extra cooling produced by this inverse Compton process can lower the X-ray emissivity of the forward shock and explain the unexpected low early X-ray flux seen in many GRBs.

  14. THE n-DISTRIBUTION OF ELECTRONS AND DOUBLE LAYERS IN THE ELECTRON-BEAM-RETURN-CURRENT SYSTEM OF SOLAR FLARES

    SciTech Connect (OSTI)

    Karlicky, Marian, E-mail: karlicky@asu.cas.cz [Astronomical Institute of the Academy of Sciences of the Czech Republic, CZ-25165 Ondrejov (Czech Republic)

    2012-05-01T23:59:59.000Z

    We investigate processes in the electron-beam-return-current system in the impulsive phase of solar flares to answer a question about the formation of the n-electron distribution detected in this phase of solar flares. An evolution of the electron-beam-return-current system with an initial local density depression is studied using a three-dimensional electromagnetic particle-in-cell model. In the system the strong double layer is formed. Its electric field potential increases with the electron beam flux. In this electric field potential, the electrons of background plasma are strongly accelerated and propagate in the return-current direction. The high-energy part of their distribution at the high-potential side of the strong double layer resembles that of the n-distribution. Thus, the detection of the n-distributions, where a form of the high-energy part of the distribution is the most important, can indicate the presence of strong double layers in solar flares. The similarity between processes in solar flare loops and those in the downward current region of the terrestrial aurora, where the double layers were observed by FAST satellite, supports this idea.

  15. Solar Flare Chromospheric Line Emission: Comparison Between IBIS High-resolution Observations and Radiative Hydrodynamic Simulations

    E-Print Network [OSTI]

    da Costa, Fatima Rubio; Petrosian, Vahé; Dalda, Alberto Sainz; Liu, Wei

    2014-01-01T23:59:59.000Z

    Solar flares involve impulsive energy release, which results in enhanced radiation in a broad spectral and at a wide height range. In particular, line emission from the chromosphere (lower atmosphere) can provide critical diagnostics of plasma heating processes. Thus, a direct comparison between high-resolution spectroscopic observations and advanced numerical modeling results can be extremely valuable, but has not been attempted so far. We present in this paper such a self-consistent investigation of an M3.0 flare observed by the Dunn Solar Telescope's (DST) Interferometric Bi-dimensional Spectrometer (IBIS) on 2011 September 24 that we have modeled with the radiative hydrodynamic code RADYN (Carlsson & Stein 1992, 1997; Abbett & Hawley 1999; Allred et al. 2005). We obtained images and spectra of the flaring region with IBIS in H$\\alpha$ 6563 \\AA\\ and Ca II 8542 \\AA, and with the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) in X-rays. The latter was used to infer the non-thermal elect...

  16. Obscuration of Flare Emission by an Eruptive Prominence

    E-Print Network [OSTI]

    Gopalswamy, Nat

    2013-01-01T23:59:59.000Z

    We report on the eclipsing of microwave flare emission by an eruptive prominence from a neighboring region as observed by the Nobeyama Radioheliograph at 17 GHz. The obscuration of the flare emission appears as a dimming feature in the microwave flare light curve. We use the dimming feature to derive the temperature of the prominence and the distribution of heating along the length of the filament. We find that the prominence is heated to a temperature above the quiet Sun temperature at 17 GHz. The duration of the dimming is the time taken by the eruptive prominence in passing over the flaring region. We also find evidence for the obscuration in EUV images obtained by the Solar and Heliospheric Observatory (SOHO) mission.

  17. Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1979-September 30, 1980

    SciTech Connect (OSTI)

    York, T.M.; Klevans, E.H.

    1980-05-01T23:59:59.000Z

    Experimental and analytical studies of particle and energy loss at the ends of a linear theta pinch have been carried out. A study of transients occurring in the formation of reversed trapped fields within the coil, and of transients in the end region of a 25 cm long device was completed. A 1-D code has proven to be highly accurate in describing loss events and defining transport mechanisms in different experiments and is described here. A study of loss along field lines in a 50 cm long device has generated new information on loss velocity, axial and radial temperature gradients, and has established an initial effort in understanding thermal loss to the walls. Rotation and parallel trapped fields have been added to the existing 0-D code. A new technique crowbar switch and magnetic field prediction code have been developed. Direct measurment of electron velocity with Thomson scattering was accomplished experimentally. A Nd-glass laser system, frequency doubled, is being developed for low density diagnostics. Theoretical results that accurately predict confinement in FRX devices are described.

  18. ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG, HINODE, AND RHESSI

    SciTech Connect (OSTI)

    Matthews, S. A.; Zharkov, S. [UCL Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, RH5 6NT UK (United Kingdom); Zharkova, V. V. [Horton D Building, Department of Mathematics, University of Bradford, Bradford, BD7 1DP (United Kingdom)

    2011-10-01T23:59:59.000Z

    Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its impact in the photosphere and the solar interior. Using data from Hinode, TRACE, RHESSI, and GONG we study the temporal and spatial evolution of the 2006 December 14 X-class flare in the chromosphere, photosphere, and the solar interior. We investigate the connections between the emission at various atmospheric depths, including acoustic signatures obtained by time-distance and holography methods from the GONG data. We report the horizontal displacements observed in the photosphere linked to the timing and locations of the acoustic signatures we believe to be associated with this flare, their vertical and horizontal displacement velocities, and their potential implications for current models of flare dynamics.

  19. SPONTANEOUS CURRENT-LAYER FRAGMENTATION AND CASCADING RECONNECTION IN SOLAR FLARES. I. MODEL AND ANALYSIS

    SciTech Connect (OSTI)

    Barta, Miroslav; Buechner, Joerg [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Karlicky, Marian; Skala, Jan, E-mail: barta@mps.mpg.de [Astronomical Institute of the Academy of Sciences of the Czech Republic, CZ-25165 Ondrejov (Czech Republic)

    2011-08-10T23:59:59.000Z

    Magnetic reconnection is commonly considered to be a mechanism of solar (eruptive) flares. A deeper study of this scenario reveals, however, a number of open issues. Among them is the fundamental question of how the magnetic energy is transferred from large, accumulation scales to plasma scales where its actual dissipation takes place. In order to investigate this transfer over a broad range of scales, we address this question by means of a high-resolution MHD simulation. The simulation results indicate that the magnetic-energy transfer to small scales is realized via a cascade of consecutively smaller and smaller flux ropes (plasmoids), analogous to the vortex-tube cascade in (incompressible) fluid dynamics. Both tearing and (driven) 'fragmenting coalescence' processes are equally important for the consecutive fragmentation of the magnetic field (and associated current density) into smaller elements. At the later stages, a dynamic balance between tearing and coalescence processes reveals a steady (power-law) scaling typical of cascading processes. It is shown that cascading reconnection also addresses other open issues in solar-flare research, such as the duality between the regular large-scale picture of (eruptive) flares and the observed signatures of fragmented (chaotic) energy release, as well as the huge number of accelerated particles. Indeed, spontaneous current-layer fragmentation and the formation of multiple channelized dissipative/acceleration regions embedded in the current layer appear to be intrinsic to the cascading process. The multiple small-scale current sheets may also facilitate the acceleration of a large number of particles. The structure, distribution, and dynamics of the embedded potential acceleration regions in a current layer fragmented by cascading reconnection are studied and discussed.

  20. Oilfield Flare Gas Electricity Systems (OFFGASES Project)

    SciTech Connect (OSTI)

    Rachel Henderson; Robert Fickes

    2007-12-31T23:59:59.000Z

    The Oilfield Flare Gas Electricity Systems (OFFGASES) project was developed in response to a cooperative agreement offering by the U.S. Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) under Preferred Upstream Management Projects (PUMP III). Project partners included the Interstate Oil and Gas Compact Commission (IOGCC) as lead agency working with the California Energy Commission (CEC) and the California Oil Producers Electric Cooperative (COPE). The project was designed to demonstrate that the entire range of oilfield 'stranded gases' (gas production that can not be delivered to a commercial market because it is poor quality, or the quantity is too small to be economically sold, or there are no pipeline facilities to transport it to market) can be cost-effectively harnessed to make electricity. The utilization of existing, proven distribution generation (DG) technologies to generate electricity was field-tested successfully at four marginal well sites, selected to cover a variety of potential scenarios: high Btu, medium Btu, ultra-low Btu gas, as well as a 'harsh', or high contaminant, gas. Two of the four sites for the OFFGASES project were idle wells that were shut in because of a lack of viable solutions for the stranded noncommercial gas that they produced. Converting stranded gas to useable electrical energy eliminates a waste stream that has potential negative environmental impacts to the oil production operation. The electricity produced will offset that which normally would be purchased from an electric utility, potentially lowering operating costs and extending the economic life of the oil wells. Of the piloted sites, the most promising technologies to handle the range were microturbines that have very low emissions. One recently developed product, the Flex-Microturbine, has the potential to handle the entire range of oilfield gases. It is deployed at an oilfield near Santa Barbara to run on waste gas that is only 4% the strength of natural gas. The cost of producing oil is to a large extent the cost of electric power used to extract and deliver the oil. Researchers have identified stranded and flared gas in California that could generate 400 megawatts of power, and believe that there is at least an additional 2,000 megawatts that have not been identified. Since California accounts for about 14.5% of the total domestic oil production, it is reasonable to assume that about 16,500 megawatts could be generated throughout the United States. This power could restore the cost-effectiveness of thousands of oil wells, increasing oil production by millions of barrels a year, while reducing emissions and greenhouse gas emissions by burning the gas in clean distributed generators rather than flaring or venting the stranded gases. Most turbines and engines are designed for standardized, high-quality gas. However, emerging technologies such as microturbines have increased the options for a broader range of fuels. By demonstrating practical means to consume the four gas streams, the project showed that any gases whose properties are between the extreme conditions also could be utilized. The economics of doing so depends on factors such as the value of additional oil recovered, the price of electricity produced, and the alternate costs to dispose of stranded gas.

  1. Gamma-Ray Polarimetry of Two X-Class Solar Flares

    E-Print Network [OSTI]

    Steven E. Boggs; W. Coburn; E. Kalemci

    2005-10-19T23:59:59.000Z

    We have performed the first polarimetry of solar flare emission at gamma-ray energies (0.2-1 MeV). These observations were performed with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) for two large flares: the GOES X4.8-class solar flare of 2002 July 23, and the X17-class flare of 2003 October 28. We have marginal polarization detections in both flares, at levels of 21% +/- 9% and -11% +/- 5% respectively. These measurements significantly constrain the levels and directions of solar flare gamma-ray polarization, and begin to probe the underlying electron distributions.

  2. THE EFFECTS OF WAVE ESCAPE ON FAST MAGNETOSONIC WAVE TURBULENCE IN SOLAR FLARES

    SciTech Connect (OSTI)

    Pongkitiwanichakul, Peera; Chandran, Benjamin D. G. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Karpen, Judith T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); DeVore, C. Richard, E-mail: pbu3@unh.edu, E-mail: benjamin.chandran@unh.edu, E-mail: judy.karpen@nasa.gov, E-mail: devore@nrl.navy.mil [Naval Research Laboratory, Washington, DC 20375 (United States)

    2012-09-20T23:59:59.000Z

    One of the leading models for electron acceleration in solar flares is stochastic acceleration by weakly turbulent fast magnetosonic waves ({sup f}ast waves{sup )}. In this model, large-scale flows triggered by magnetic reconnection excite large-wavelength fast waves, and fast-wave energy then cascades from large wavelengths to small wavelengths. Electron acceleration by large-wavelength fast waves is weak, and so the model relies on the small-wavelength waves produced by the turbulent cascade. In order for the model to work, the energy cascade time for large-wavelength fast waves must be shorter than the time required for the waves to propagate out of the solar-flare acceleration region. To investigate the effects of wave escape, we solve the wave kinetic equation for fast waves in weak turbulence theory, supplemented with a homogeneous wave-loss term. We find that the amplitude of large-wavelength fast waves must exceed a minimum threshold in order for a significant fraction of the wave energy to cascade to small wavelengths before the waves leave the acceleration region. We evaluate this threshold as a function of the dominant wavelength of the fast waves that are initially excited by reconnection outflows.

  3. ROSAT Observations of the Flare Star CC Eri

    E-Print Network [OSTI]

    H. C. Pan; C. Jordan

    1994-09-16T23:59:59.000Z

    The flare/spotted spectroscopic binary star CC Eri was observed with the Position Sensitive Proportional Counter (PSPC) on the X-ray satellite ROSAT on 1990 July 9-11 and 1992 January 26-27. During the observations, the source was variable on time scales from a few minutes to several hours, with the X-ray (0.2-2 keV) luminosity in the range $\\sim 2.5-6.8\\times 10^{29} erg s^{-1}$. An X-ray flare-like event, which has a one hour characteristic rise time and a two hour decay time, was observed from CC Eri on 1990 July 10 16:14-21:34 (UT). The X-ray spectrum of the source can be described by current thermal plasma codes with two temperature components or with a continuous temperature distribution. The spectral results show that plasma at $Te\\sim 10^{7}$ K exists in the corona of CC Eri. The variations in the observed source flux and spectra can be reproduced by a flare, adopting a magnetic reconnection model. Comparisons with an unheated model, late in the flare, suggest that the area and volume of the flare are substantially larger than in a solar two ribbon flare, while the electron pressure is similar. The emission measure and temperature of the non-flaring emission, interpreted as the average corona, lead to an electron pressure similar to that in a well-developed solar active region. Rotational modulation of a spot related active region requires an unphysically large X-ray flux in a concentrated area.

  4. The Carina Flare: What can fragments in the wall tell us?

    E-Print Network [OSTI]

    Wunsch, Richard; Sidorin, Vojtech; Ehlerova, Sona; Palous, Jan; Dale, James; Dawson, Joanne R; Fukui, Yasuo

    2011-01-01T23:59:59.000Z

    $^{13}$CO(J=2--1) and C$^{18}$O(J=2--1) observations of the molecular cloud G285.90+4.53 (Cloud~16) in the Carina Flare supershell (GSH287+04-17) with the APEX telescope are presented. With an algorithm DENDROFIND we identify 51 fragments and compute their sizes and masses. We discuss their mass spectrum and interpret it as being the result of the shell fragmentation process described by the pressure assisted gravitational instability - PAGI. We conclude that the explanation of the clump mass function needs a combination of gravity with pressure external to the shell.

  5. E-Print Network 3.0 - alberta flare research Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    FLARES Yingna Su,1,2 Leon Golub... ) footpoints in two-ribbon flares, using the high spatial resolution data obtained in 1998Y2005 by TRACE. To do... this study, we have...

  6. E-Print Network 3.0 - acute gout flare Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    gout flare Search Powered by Explorit Topic List Advanced Search Sample search results for: acute gout flare Page: << < 1 2 3 4 5 > >> 1 Uricase for gout treatment Chapter 5.1...

  7. Repeated X-ray Flaring Activity in Sagittarius A*

    E-Print Network [OSTI]

    Guillaume Belanger; Andrea Goldwurm; Fulvio Melia; Farah Yusef-Zadeh; Philippe Ferrando; Delphine Porquet; Nicolas Grosso; Robert Warwick

    2005-08-19T23:59:59.000Z

    Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms in this supermassive black hole located at the center of our Galaxy. Several X-ray flares with varying durations and spectral features have already been observed from this object. Here we present the results of two long XMM-Newton observations of the Galactic nucleus carried out in 2004, for a total exposure time of nearly 500 ks. During these observations we detected two flares from Sgr A* with peak 2-10 keV luminosities about 40 times (L ~ 9x10^34 erg s?1) above the quiescent luminosity: one on 2004 March 31 and another on 2004 August 31. The first flare lasted about 2.5 ks and the second about 5 ks. The combined fit on the Epic spectra yield photon indeces of about 1.5 and 1.9 for the first and second flare respectively. This hard photon index strongly suggests the presence of an important population of non-thermal electrons during the event and supports the view that the majority of flaring events tend to be hard and not very luminous.

  8. Solar Flare Intermittency and the Earth's Temperature Anomalies Nicola Scafetta1,2

    E-Print Network [OSTI]

    Scafetta, Nicola

    Solar Flare Intermittency and the Earth's Temperature Anomalies Nicola Scafetta1,2 and Bruce J; published 17 June 2003) We argue that Earth's short-term temperature anomalies and the solar flare data sets that corresponds to the one that would be induced by the solar flare intermittency. The mean

  9. Flares GRAVITY Relativistic simulations Conclusion Simulating observations to test GR at the

    E-Print Network [OSTI]

    Gourgoulhon, Eric

    Flares GRAVITY Relativistic simulations Conclusion Simulating observations to test GR at the Galactic Center with GRAVITY GR19 Mexico Frédéric VINCENT1 Thibaut PAUMARD2 , Eric GOURGOULHON3 , Guy at the Galactic Center #12;Flares GRAVITY Relativistic simulations Conclusion 1 Sagittarius A* : a flaring black

  10. Simulations of Spectral Profiles Observed in a C5.6 Limb Flare

    E-Print Network [OSTI]

    Li, Hui

    , Nanjing 210008, China Abstract We obtained a complete set of H# , CaII 8542 Å¡ A and HeI 10830 Å¡ A spectra of the flare loop. Key words: limb flare, line profile, infrared PACS: 1 Introduction Solar flare spectra velocities, electron temperatures and densities [1--4]. Spectral lines are thought be wide in solar limb

  11. Automatic Solar Flare Detection Using MLP, RBF and SVM , Frank Y. Shih1

    E-Print Network [OSTI]

    in light curves. In the mean time, solar flares also emit high velocity charged particles that take one1 Automatic Solar Flare Detection Using MLP, RBF and SVM Ming Qu1 , Frank Y. Shih1 , Ju Jing2. The focus of the automatic solar flare detection is on the development of efficient feature

  12. Energy Partitions and Evolution in a Purely Thermal Solar Flare

    E-Print Network [OSTI]

    Fleishman, Gregory D; Gary, Dale E

    2015-01-01T23:59:59.000Z

    This paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free-free emission it produced. An advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. When combined with observationally-deduced plasma density and temperature, these magnetic field measurements offer a straightforward way of tracking evolution of the magnetic and thermal energies in the flare. For the event described here, the magnetic energy density in the radio-emitting volume declines over the flare rise phase, then stays roughly constant during the extended peak phase, but recovers to the original level over the decay phase. At the stage where the magnetic energy density decreases, the thermal energy density increases; however, this increase is insufficient, by roughly an order of magnitude, to compensate for the magnetic energy decrease. When the magnetic energy release is over, the source parameters come back to ne...

  13. A Testable the Stochastic Acceleration Model for Flares in Sagittarius A*

    E-Print Network [OSTI]

    Siming Liu; Vahe Petrosian; Fulvio Melia; Christopher L. Fryer

    2006-09-16T23:59:59.000Z

    The near-IR and X-ray flares in Sagittarius A* are believed to be produced by relativistic electrons via synchrotron and synchrotron self-Comptonization, respectively. These electrons are likely energized by turbulent plasma waves through second-order Fermi acceleration that, in combination with the radiative cooling processes, produces a relativistic Maxwellian distribution in the steady state. This model has four principal parameters, namely the magnetic field B, the electron density n and temperature \\gamma_c mec2, and the size of the flare region R. In the context of stochastic acceleration, the quantities Rn^1/2B and \\gamma_cRn should remain nearly constant in time. Therefore, simultaneous spectroscopic observations in the NIR and X-ray bands can readily test the model, which, if proven to be valid, may be used to determine the evolution of the plasma properties during an eruptive event with spectroscopic observations in either band or simultaneous flux density measurements in both bands. The formulae can be applied to other isolated or confined systems, where electrons are accelerated to relativistic energies by plasma wave turbulence and produce most of the emission via synchrotron processes.

  14. NEUTRINO-COOLED ACCRETION MODEL WITH MAGNETIC COUPLING FOR X-RAY FLARES IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Luo Yang; Gu Weimin; Liu Tong; Lu Jufu, E-mail: guwm@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

    2013-08-20T23:59:59.000Z

    The neutrino-cooled accretion disk, which was proposed to work as the central engine of gamma-ray bursts, encounters difficulty in interpreting the X-ray flares after the prompt gamma-ray emission. In this paper, the magnetic coupling (MC) between the inner disk and the central black hole (BH) is taken into consideration. For mass accretion rates around 0.001 {approx} 0.1 M{sub Sun} s{sup -1}, our results show that the luminosity of neutrino annihilation can be significantly enhanced due to the coupling effects. As a consequence, after the gamma-ray emission, a remnant disk with mass M{sub disk} {approx}< 0.5 M{sub Sun} may power most of the observed X-ray flares with the rest frame duration less than 100 s. In addition, a comparison between the MC process and the Blandford-Znajek mechanism is shown on the extraction of BH rotational energy.

  15. Magnetic and dynamical photospheric disturbances observed during an M3.2 solar flare

    E-Print Network [OSTI]

    Kuckein, C; Sainz, R Manso

    2015-01-01T23:59:59.000Z

    This letter reports on a set of full-Stokes spectropolarimetric observations in the near infrared He I 10830 A spectral region covering the pre-, flare, and post-flare phases of an M3.2 class solar flare. The flare originated on 2013 May 17 and belonged to active region NOAA 11748. We detected strong He I 10830 A emission in the flare. The red component of the He I triplet peaks at an intensity ratio to the continuum of about 1.86. During the flare, He I Stokes V is substantially larger and appears reversed compared to the usually larger Si I Stokes V profile. The photospheric Si I inversions of the four Stokes profiles reveal the following: (1) the magnetic field strength in the photosphere decreases or is even absent during the flare phase, as compared to the pre-flare phase. However, this decrease is not permanent. After the flare the magnetic field recovers its pre-flare configuration in a short time (i.e., in 30 minutes after the flare). (2) In the photosphere, the line-of-sight velocities show a regular...

  16. Magnetic Flares and the Observed Optical Depth in Seyfert Galaxies

    E-Print Network [OSTI]

    Sergei Nayakshin; Fulvio Melia

    1997-05-30T23:59:59.000Z

    We here consider the pressure equilibrium during an intense magnetic flare above the surface of a cold accretion disk. Under the assumption that the heating source for the plasma trapped within the flaring region is an influx of energy transported inwards with a group velocity close to $c$, e.g., by magnetohydrodynamic waves, this pressure equilibrium can constrain the Thomson optical depth $\\tau_T$ to be of order unity. We suggest that this may be the reason why $\\tau_T\\sim 1$ in Seyfert Galaxies. We also consider whether current data can distinguish between the spectrum produced by a single X-ray emitting region with $\\tau_T\\sim 1$ and that formed by many different flares spanning a range of $\\tau_T$. We find that the current observations do not yet have the required energy resolution to permit such a differentiation. Thus, it is possible that the entire X-ray/$\\gamma$-ray spectrum of Seyfert Galaxies is produced by many independent magnetic flares with an optical depth $0.5<\\tau_T<2$.

  17. SOLAR FLARE CYCLES , M. D. POPESCU1, 2

    E-Print Network [OSTI]

    on the solar disk. They occur when magnetic field loops undergo reorganization, releasing energy into the solar of a large amount of magnetic energy, previously stored in the solar corona, and dissipated through magneticSOLAR FLARE CYCLES G. MARI1 , M. D. POPESCU1, 2 1 Astronomical Institute of the Romanian Academy

  18. Global Energetics of Solar Flares: II. Thermal Energies

    E-Print Network [OSTI]

    Aschwanden, M J; Ryan, D; Caspi, A; McTiernan, J M; Warren, H P

    2015-01-01T23:59:59.000Z

    We present the second part of a project on the global energetics of solar flares and CMEs that includes about 400 M- and X-class flares observed with AIA/SDO during the first 3.5 years of its mission. In this Paper II we compute the differential emission measure (DEM) distribution functions and associated multi-thermal energies, using a spatially-synthesized Gaussian DEM forward-fitting method. The multi-thermal DEM function yields a significantly higher (by an average factor of $\\approx 14$), but more comprehensive (multi-)thermal energy than an isothermal energy estimate from the same AIA data. We find a statistical energy ratio of $E_{th}/E_{diss} \\approx 2\\%-40\\%$ between the multi-thermal energy $E_{th}$ and the magnetically dissipated energy $E_{diss}$, which is an order of magnitude higher than the estimates of Emslie et al.~2012. For the analyzed set of M and X-class flares we find the following physical parameter ranges: $L=10^{8.2}-10^{9.7}$ cm for the length scale of the flare areas, $T_p=10^{5.7}-...

  19. ARE CORONAE OF MAGNETICALLY ACTIVE STARS HEATED BY FLARES? II. EXTREME ULTRAVIOLET AND X-RAY FLARE STATISTICS AND THE

    E-Print Network [OSTI]

    Audard, Marc

    @astro.columbia.edu Vinay L. Kashyap and Jeremy J. Drake Harvard-Smithsonian Center for Astrophysics, 60 Garden Street distribution in radiated energy of the late-type active star AD Leo. Occurrence rates of solar flares have almost 2 orders of magnitude in their radiated energy. We compare the observed light curves with light

  20. GAMMA-RAY FLARES FROM RED GIANT/JET INTERACTIONS IN ACTIVE GALACTIC NUCLEI

    SciTech Connect (OSTI)

    Barkov, Maxim V.; Aharonian, Felix A.; Bosch-Ramon, ValentI, E-mail: bmv@mpi-hd.mpg.d [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2010-12-01T23:59:59.000Z

    Non-blazar active galactic nuclei (AGNs) have been recently established as a class of gamma-ray sources. M87, a nearby representative of this class, shows fast TeV variability on timescales of a few days. We suggest a scenario of flare gamma-ray emission in non-blazar AGNs based on a red giant (RG) interacting with the jet at the base. We solve the hydrodynamical equations that describe the evolution of the envelope of an RG blown by the impact of the jet. If the RG is at least slightly tidally disrupted by the supermassive black hole, enough stellar material will be blown by the jet, expanding quickly until a significant part of the jet is shocked. This process can render suitable conditions for energy dissipation and proton acceleration, which could explain the detected day-scale TeV flares from M87 via proton-proton collisions. Since the radiation produced would be unbeamed, such an event should be mostly detected from non-blazar AGNs. They may be frequent phenomena, detectable in the GeV-TeV range even up to distances of {approx}1 Gpc for the most powerful jets. The counterparts at lower energies are expected to be not too bright. M87, and nearby non-blazar AGNs in general, can be fast variable sources of gamma-rays through RG/jet interactions.

  1. Spontaneous current-layer fragmentation and cascading reconnection in solar flares: I. Model and analysis

    E-Print Network [OSTI]

    Bárta, Miroslav; Karlický, Marian; Skála, Jan

    2010-01-01T23:59:59.000Z

    Magnetic reconnection is commonly considered as a mechanism of solar (eruptive) flares. A deeper study of this scenario reveals, however, a number of open issues. Among them is the fundamental question, how the magnetic energy is transferred from large, accumulation scales to plasma scales where its actual dissipation takes place. In order to investigate this transfer over a broad range of scales we address this question by means of high-resolution MHD simulation. The simulation results indicate, that the magnetic-energy transfer to small scales is realized via a cascade of consecutive smaller and smaller flux-ropes (plasmoids), in analogy with the vortex-tube cascade in (incompressible) fluid dynamics. Both tearing and (driven) coalescence processes are equally important for the consecutive fragmentation of the magnetic field (and associated current density) to smaller elements. At the later stages a dynamic balance between tearing and coalescence processes reveals a steady (power-law) scaling typical for ca...

  2. The optical flare and afterglow light curve of GRB 050904 at redshift z=6.29

    E-Print Network [OSTI]

    D. M. Wei; T. Yan; Y. Z. Fan

    2005-12-07T23:59:59.000Z

    GRB050904 is very interesting since it is by far the most distant GRB event known to date($z=6.29$). It was reported that during the prompt high energy emission phase, a very bright optical flare was detected, and it was temporal coincident with an X-ray flare. Here we use two models to explain the optical flare, One is the "late internal shock model", in which the optical flare is produced by the synchrotron radiation of the electrons accelerated by the late internal shock, and the X-ray flare is produced by the synchrotron-self-Compton mechanism. The other is the external forward-reverse shock model, in which the optical flare is from the reverse shock emission and the X-ray flare is attributed to the central engine activity. We show that with proper parameters, a bright optical flare can appear in both models. We think the "late internal shock model" is more favored since in this model the optical flash and the X-ray flare have the same origin, which provides a natural explanation of the temporal coincidence of them. In the forward-reverse shock scenario, fits to the optical flare and the late afterglow suggests that the physical parameters of the reverse shock are much different from that of forward shock, as found in modeling the optical flash of GRB 990123 previously.

  3. High-Energy Gamma-Ray Emission From Solar Flares: Summary of Fermi LAT Detections and Analysis of Two M-Class Flares

    E-Print Network [OSTI]

    ,

    2013-01-01T23:59:59.000Z

    We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast Coronal Mass Ejections (CMEs) and are not all powerful X-ray flares. We then describe the detailed temporal, spatial and spectral characteristics of the first two long-lasting events: the 2011 March 7 flare, a moderate (M3.7) impulsive flare followed by slowly varying gamma-ray emission over 13 hours, and the 2011 June 7 M2.5 flare, which was followed by gamma-ray emission lasting for 2 hours. We compare the Fermi-LAT data with X-ray and proton data measurements from GOES and RHESSI. We argue that a hadronic origin of the gamma rays is more likely than a leptonic origin and find that the energy spectrum of the proton distribution softens after the 2011 March 7 flare, favoring a scenario with continuous acceleration at the flare site. This work suggests that proton acceleratio...

  4. Diagnostics of stellar flares from X-ray observations: from the decay to the rise phase

    E-Print Network [OSTI]

    F. Reale

    2007-05-23T23:59:59.000Z

    The diagnostics of stellar flaring coronal loops have been so far largely based on the analysis of the decay phase. We derive new diagnostics from the analysis of the rise and peak phase of stellar flares. We release the assumption of full equilibrium of the flaring loop at the flare peak, according to the frequently observed delay between the temperature and the density maximum. From scaling laws and hydrodynamic simulations we derive diagnostic formulas as a function of observable quantities and times. We obtain a diagnostic toolset related to the rise phase, including the loop length, density and aspect ratio. We discuss the limitations of this approach and find that the assumption of loop equilibrium in the analysis of the decay leads to a moderate overestimate of the loop length. A few relevant applications to previously analyzed stellar flares are shown. The analysis of the flare rise and peak phase complements and completes the analysis of the decay phase.

  5. A Flared, Orbiting, Dusty Disk Around HD 233517

    E-Print Network [OSTI]

    M. Jura

    2002-09-13T23:59:59.000Z

    We find that the infrared excess around HD 233517, a first ascent red giant, can be naturally explained if the star possesses an orbiting, flared dusty disk. We estimate that the outer radius of this disk is 45 AU and that the total mass within the disk is about 0.01 the mass of the Sun. We speculate that this disk is the result of the engulfment of a low mass companion star that occurred when HD 233517 became a red giant.

  6. Seismic Emissions from a Highly Impulsive M6.7 Solar Flare

    E-Print Network [OSTI]

    J. C. Martinez-Oliveros; H. Moradi; A-C. Donea

    2008-01-09T23:59:59.000Z

    On 10 March 2001 the active region NOAA 9368 produced an unusually impulsive solar flare in close proximity to the solar limb. This flare has previously been studied in great detail, with observations classifying it as a type 1 white-light flare with a very hard spectrum in hard X-rays. The flare was also associated with a type II radio burst and coronal mass ejection. The flare emission characteristics appeared to closely correspond with previous instances of seismic emission from acoustically active flares. Using standard local helioseismic methods, we identified the seismic signatures produced by the flare that, to date, is the least energetic (in soft X-rays) of the flares known to have generated a detectable acoustic transient. Holographic analysis of the flare shows a compact acoustic source strongly correlated with the impulsive hard X-ray, visible continuum, and radio emission. Time-distance diagrams of the seismic waves emanating from the flare region also show faint signatures, mainly in the eastern sector of the active region. The strong spatial coincidence between the seismic source and the impulsive visible continuum emission reinforces the theory that a substantial component of the seismic emission seen is a result of sudden heating of the low photosphere associated with the observed visible continuum emission. Furthermore, the low-altitude magnetic loop structure inferred from potential--field extrapolations in the flaring region suggests that there is a significant inverse correlation between the seismicity of a flare and the height of the magnetic loops that conduct the particle beams from the corona.

  7. Magnetic Energy Dissipation during the 2014 March 29 Solar Flares

    E-Print Network [OSTI]

    Aschwanden, Markus J

    2015-01-01T23:59:59.000Z

    We calculated the time evolution of the free magnetic energy during the 2014-Mar-29 flare (SOL2014-03-29T17:48), the first X-class flare detected by IRIS. The free energy was calculated from the difference between the nonpotential field, constrained by the geometry of observed loop structures, and the potential field. We use AIA/SDO and IRIS images to delineate the geometry of coronal loops in EUV wavelengths, as well as to trace magnetic field directions in UV wavelengths in the chromosphere and transition region. We find an identical evolution of the free energy for both the coronal and chromospheric tracers, as well as agreement between AIA and IRIS results, with a peak free energy of $E_{free}(t_{peak}) \\approx (45 \\pm 2) \\times 10^{30}$ erg, which decreases by an amount of $\\Delta E_{free} \\approx (29 \\pm 3) \\times 10^{30}$ erg during the flare decay phase. The consistency of free energies measured from different EUV and UV wavelengths for the first time here, demonstrates that vertical electric currents...

  8. Stochastic Electron Acceleration During the NIR and X-ray Flares in Sagittarius A*

    E-Print Network [OSTI]

    Siming Liu; Fulvio Melia; Vahe Petrosian

    2005-06-07T23:59:59.000Z

    Recent near-IR (NIR) and X-ray observations of Sagittarius A*'s spectrum have yielded several strong constraints on the transient energization mechanism, justifying a re-examination of the stochastic acceleration model proposed previously for these events. We here demonstrate that the new results are fully consistent with the acceleration of electrons via the transit-time damping process. But more importantly, these new NIR and X-ray flares now can constrain the source size, the gas density, the magnetic field, and the wave energy density in the turbulent plasma. Future simultaneous multi-wavelength observations with good spectral information will, in addition, allow us to study their temporal evolution, which will eventually lead to an accurate determination of the behavior of the plasma just minutes prior to its absorption by the black hole.

  9. LPG recovery from refinery flare by waste heat powered absorption refrigeration

    SciTech Connect (OSTI)

    Erickson, D.C.; Kelly, F.

    1998-07-01T23:59:59.000Z

    A waste heat powered ammonia Absorption Refrigeration Unit (ARU) has commenced operation at the Colorado Refining Company in Commerce City, Colorado. The ARU provides 85 tons of refrigeration at 30 F to refrigerate the net gas/treat gas stream, thereby recovering 65,000 barrels per year of LPG which formerly was flared or burned as fuel. The ARU is powered by the 290 F waste heat content of the reform reactor effluent. An additional 180 tons of refrigeration is available at the ARU to debottleneck the FCC plant wet gas compressors by cooling their inlet vapor. The ARU is directly integrated into the refinery processes, and uses enhanced, highly compact heat and mass exchange components. The refinery's investment will pay back in less than two years from increased recovery of salable product, and CO{sub 2} emissions are decreased by 10,000 tons per year in the Denver area.

  10. Heat Loss Measurement Using Infrared Imaging

    E-Print Network [OSTI]

    Seeber, S. A.

    1983-01-01T23:59:59.000Z

    in various applications. Examples of two applications are presented. The first describes the development of heat balance data for a solvent refined coal processing unit. The second describes the measurement of heat loss and thermal resistance in a double...

  11. X-ray flaring from the young stars in CygnusOB2

    E-Print Network [OSTI]

    J. F. Albacete Colombo; M. Caramazza; E. Flaccomio; G. Micela; S. Sciortino

    2007-08-17T23:59:59.000Z

    Aims: We characterize individual and ensemble properties of X-ray flares from stars in the CygOB2 and ONC star-forming regions. Method: We analyzed X-ray lightcurves of 1003 CygOB2 sources observed with Chandra for 100 ksec and of 1616 ONC sources detected in the ``Chandra Orion Ultra-deep Project'' 850 ksec observation. We employed a binning-free maximum likelihood method to segment the light-curves into intervals of constants signal and identified flares on the basis of both the amplitude and the time-derivative of the source luminosity. We then derived and compared the flare frequency and energy distribution of CygOB2 and ONC sources. The effect of the length of the observation on these results was investigated by repeating the statistical analysis on five 100 ksec-long segments extracted from the ONC data. Results: We detected 147 and 954 flares from the CygOB2 and ONC sources, respectively. The flares in CygOB2 have decay times ranging from ~0.5 to about 10 hours. The flare energy distributions of all considered flare samples are described at high energies well by a power law with index alpha=-(2.1+-0.1). At low energies, the distributions flatten, probably because of detection incompleteness. We derived average flare frequencies as a function of flare energy. The flare frequency is seen to depend on the source's intrinsic X-ray luminosity, but its determination is affected by the length of the observation. The slope of the high-energy tail of the energy distribution is, however, affected little. A comparison of CygOB2 and ONC sources, accounting for observational biases, shows that the two populations, known to have similar X-ray emission levels, have very similar flare activity.

  12. GeV-TeV and X-ray flares from gamma-ray bursts

    E-Print Network [OSTI]

    Xiang-Yu Wang; Zhuo Li; Peter Meszaros

    2006-03-13T23:59:59.000Z

    The recent detection of delayed X-ray flares during the afterglow phase of gamma-ray bursts (GRBs) suggests an inner-engine origin, at radii inside the deceleration radius characterizing the beginning of the forward shock afterglow emission. Given the observed temporal overlapping between the flares and afterglows, there must be inverse Compton (IC) emission arising from such flare photons scattered by forward shock afterglow electrons. We find that this IC emission produces GeV-TeV flares, which may be detected by GLAST and ground-based TeV telescopes. We speculate that this kind of emission may already have been detected by EGRET from a very strong burst--GRB940217. The enhanced cooling of the forward shock electrons by the X-ray flare photons may suppress the synchrotron emission of the afterglows during the flare period. The detection of GeV-TeV flares combined with low energy observations may help to constrain the poorly known magnetic field in afterglow shocks. We also consider the self-IC emission in the context of internal-shock and external-shock models for X-ray flares. The emission above GeV from internal shocks is low, while the external shock model can also produce GeV-TeV flares, but with a different temporal behavior from that caused by IC scattering of flare photons by afterglow electrons. This suggests a useful approach for distinguishing whether X-ray flares originate from late central engine activity or from external shocks.

  13. GRB 060714: No Clear Dividing Line Between Prompt Emission and X-Ray Flares

    SciTech Connect (OSTI)

    Krimm, Hans A.; /NASA, Goddard /Universities Space Research Assoc.; Granot, J.; /KIPAC, Menlo Park; Marshal, F.; /NASA, Goddard; Perri, M.; /ASDC, Frascati; Barthelmy, S.D.; /NASA, Goddard; Burrows, D.N.; /Penn State U., Astron. Astrophys.; Gehrels, N.; /NASA, Goddard; Meszaros, P.; Morris, D.; /Penn State U., Astron. Astrophys.; ,

    2007-02-26T23:59:59.000Z

    The long gamma-ray burst GRB 060714 was observed to exhibit a series of five X-ray flares beginning {approx} 70 s after the burst trigger T{sub 0} and continuing until {approx} T{sub 0} + 200 s. The first two flares were detected by the Burst Alert Telescope (BAT) on the Swift satellite, before Swift had slewed to the burst location, while the last three flares were strongly detected by the X-Ray Telescope (XRT) but only weakly detected by the BAT. This burst provides an unusual opportunity to track a complete sequence of flares over a wide energy range. The flares were very similar in their light curve morphology, showing power-law rise and fall components, and in most cases significant sub-structure. The flares also showed strong evolution with time, both spectrally and temporally. The small time scale and large amplitude variability observed are incompatible with an external shock origin for the flares, and support instead late time sporadic activity either of the central source or of localized dissipation events within the outflow. We show that the flares in GRB 060714 cannot be the result of internal shocks in which the contrast in the Lorentz factor of the colliding shells is very small, and that this mechanism faces serious difficulties in most Swift GRBs. The morphological similarity of the flares and the prompt emission and the gradual and continual evolution of the flares with time makes it difficult and arbitrary to draw a dividing line between the prompt emission and the flares.

  14. Natural Gas Vented and Flared (Summary)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia,(Million Barrels) Crude Oil Reserves in Nonproducing ReservoirsYear-Month Week 1 Week 2 Week 3Processing:UsedNA NA NA

  15. The contribution of microbunching instability to solar flare emission in the GHz to THz range of frequencies

    SciTech Connect (OSTI)

    Klopf, J. Michael [William and Mary College; Kaufmann, Pierre; Raulin, Jean-Pierre; Szpigel, Sergio

    2014-07-01T23:59:59.000Z

    Recent solar flare observations in the sub-terahertz range have provided evidence of a new spectral component with fluxes increasing for larger frequencies, separated from the well-known microwave emission that maximizes in the gigahertz range. Suggested interpretations explain the terahertz spectral component but do not account for the simultaneous microwave component. We present a mechanism for producing the observed "double spectra." Based on coherent enhancement of synchrotron emission at long wavelengths in laboratory accelerators, we consider how similar processes may occur within a solar flare. The instability known as microbunching arises from perturbations that produce electron beam density modulations, giving rise to broadband coherent synchrotron emission at wavelengths comparable to the characteristic size of the microbunch structure. The spectral intensity of this coherent synchrotron radiation (CSR) can far exceed that of the incoherent synchrotron radiation (ISR), which peaks at a higher frequency, thus producing a double-peaked spectrum. Successful CSR simulations are shown to fit actual burst spectral observations, using typical flaring physical parameters and power-law energy distributions for the accelerated electrons. The simulations consider an energy threshold below which microbunching is not possible because of Coulomb repulsion. Only a small fraction of the radiating charges accelerated to energies above the threshold is required to produce the microwave component observed for several events. The ISR/CSR mechanism can occur together with other emission processes producing the microwave component. It may bring an important contribution to microwaves, at least for certain events where physical conditions for the occurrence of the ISR/CSR microbunching mechanism are possible.

  16. Unveiling the origin of X-ray flares in Gamma-Ray Bursts

    E-Print Network [OSTI]

    Chincarini, G; Margutti, R; Bernardini, M G; Guidorzi, C; Pasotti, F; Giannios, D; Della Valle, M; Moretti, A; Romano, P; D'Avanzo, P; Cusumano, G; Giommi, P

    2010-01-01T23:59:59.000Z

    We present an updated catalog of 113 X-ray flares detected by Swift in the ~33% of the X-ray afterglows of Gamma-Ray Bursts (GRB). 43 flares have a measured redshift. For the first time the analysis is performed in 4 different X-ray energy bands, allowing us to constrain the evolution of the flare temporal properties with energy. We find that flares are narrower at higher energies: their width follows a power-law relation w~E^{-0.5} reminiscent of the prompt emission. Flares are asymmetric structures, with a decay time which is twice the rise time on average. Both time scales linearly evolve with time, giving rise to a constant rise-to-decay ratio: this implies that both time scales are stretched by the same factor. As a consequence, the flare width linearly evolves with time to larger values: this is a key point that clearly distinguishes the flare from the GRB prompt emission. The flare 0.3-10 keV peak luminosity decreases with time, following a power-law behaviour with large scatter: L_{pk}~ t_{pk}^{-2.7}....

  17. FLARE HEATING IN STELLAR CORONAE Vinay L. Kashyap and Jeremy J. Drake

    E-Print Network [OSTI]

    Audard, Marc

    for Astrophysics, 60 Garden Street, Cambridge, MA 02138; vkashyap@cfa.harvard.edu, jdrake 2002 March 25; accepted 2002 August 2 ABSTRACT An open question in the field of solar and stellar to flares that are increasingly less energetic but are more numerous. Previous analyses of flares in light

  18. Free Magnetic Energy and Flare Productivity of Active Regions , Changyi Tan2,3

    E-Print Network [OSTI]

    Free Magnetic Energy and Flare Productivity of Active Regions Ju Jing1 , Changyi Tan2,3 , Yuan Yuan with which we are able to estimate the free magnetic energy stored in the active regions. The magnitude scaling correlation between the free magnetic energy and the soft X-ray flare index of active regions

  19. Regularized reconstruction of the differential emission measure from solar flare hard X-ray spectra

    E-Print Network [OSTI]

    Piana, Michele

    Regularized reconstruction of the differential emission measure from solar flare hard X-ray spectra for solar flare hard X-rays, it is currently unclear whether the electron distribution responsible between (T) and J( ). However, in the last years, two issues have made this inversion problem more

  20. CONSERVATION OF BOTH CURRENT AND HELICITY IN A QUADRUPOLAR MODEL FOR SOLAR FLARES

    E-Print Network [OSTI]

    Melrose, Don

    is neglected. 1. Introduction Solar flares are attributed to magnetic energy release in the solar coronaCONSERVATION OF BOTH CURRENT AND HELICITY IN A QUADRUPOLAR MODEL FOR SOLAR FLARES DON MELROSE School of Physics,University of Sydney, NSW 2006, Australia (Received 25 Novemebr 2003; accepted 9

  1. White-light flares: A TRACE/RHESSI overview H. S. Hudson

    E-Print Network [OSTI]

    Hudson, Hugh

    White-light flares: A TRACE/RHESSI overview H. S. Hudson Space Sciences Laboratory, University includes a "white light" imaging capability with novel characteristics. Many flares with such white. The spectral response of the TRACE white-light passband extends into the UV, so these data capture

  2. Broadening Calculation of the HeI 10830 A Line in Solar Limb Flare

    E-Print Network [OSTI]

    Li, Hui

    Broadening Calculation of the HeI 10830 °A Line in Solar Limb Flare LI Hui and YOU Jianqi Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China Abstract The Doppler broadening, Stark broadening and various kinds of broadening param- eters of the HeI 10830 °A line in solar flare

  3. Broadening Calculation of the HeI 10830 A Line in Solar Limb Flare #

    E-Print Network [OSTI]

    Li, Hui

    Broadening Calculation of the HeI 10830 š A Line in Solar Limb Flare # LI Hui and YOU Jianqi Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China Abstract The Doppler broadening, Stark broadening and various kinds of broadening param­ eters of the HeI 10830 š A line in solar flare

  4. Seismic Emissions from a Highly Impulsive M6.7 Solar Flare

    E-Print Network [OSTI]

    California at Berkeley, University of

    Seismic Emissions from a Highly Impulsive M6.7 Solar Flare J.C. Mart´inez-Oliveros, H. Moradi, A characteristics appeared to closely correspond with previous instances of seismic emission from acoustically active flares. Using standard local helioseismic methods, we identified the seismic sig- natures produced

  5. NEUTRON AND ELECTROMAGNETIC EMISSIONS DURING THE 1990 MAY 24 SOLAR FLARE

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    NEUTRON AND ELECTROMAGNETIC EMISSIONS DURING THE 1990 MAY 24 SOLAR FLARE L. G. KOCHAROV,* JEONGWOO revised form 15 July, 1994) Abstract. In this paper, we are primarilyconcerned with the solar neutron emission during the 1990 May 24 flare, utilizing the counting rate of the Climax neutron monitor

  6. Topology and current ribbons: A model for current, reconnection and flaring in a complex, evolving corona

    E-Print Network [OSTI]

    Longcope, Dana

    (MCC), for the build­up of magnetic energy in a three­dimensional corona of arbitrary geometry. The MCCTopology and current ribbons: A model for current, reconnection and flaring in a complex, evolving of energy from the Sun's chromosphere and corona. The build­up and release of energy in a flare has been

  7. Using the Maximum X-ray Flux Ratio and X-ray Background to Predict Solar Flare Class

    E-Print Network [OSTI]

    Winter, Lisa M

    2015-01-01T23:59:59.000Z

    We present the discovery of a relationship between the maximum ratio of the flare flux (namely, 0.5-4 Ang to the 1-8 Ang flux) and non-flare background (namely, the 1-8 Ang background flux), which clearly separates flares into classes by peak flux level. We established this relationship based on an analysis of the Geostationary Operational Environmental Satellites (GOES) X-ray observations of ~ 50,000 X, M, C, and B flares derived from the NOAA/SWPC flares catalog. Employing a combination of machine learning techniques (K-nearest neighbors and nearest-centroid algorithms) we show a separation of the observed parameters for the different peak flaring energies. This analysis is validated by successfully predicting the flare classes for 100% of the X-class flares, 76% of the M-class flares, 80% of the C-class flares and 81% of the B-class flares for solar cycle 24, based on the training of the parametric extracts for solar flares in cycles 22-23.

  8. PUBLISHED ONLINE: 15 AUGUST 2010 | DOI: 10.1038/NPHYS1741 The effect of flares on total solar irradiance

    E-Print Network [OSTI]

    Loss, Daniel

    - quality space instrumentation has been purpose built. However, the total energy radiated by flares and itsLETTERS PUBLISHED ONLINE: 15 AUGUST 2010 | DOI: 10.1038/NPHYS1741 The effect of flares on total flares, from our own Sun, are the most energetic events in the solar system, in comparison to the total

  9. Flare Noise Reduction Exxon Chemical- Baytown Olefins Plant: 1994 CMA Energy Efficiency Award for "Flare Noise Reduction" in the category of "Public Outreach/Plant Site"

    E-Print Network [OSTI]

    Bradham, S.; Stephan, R.

    frequency noise that resembles the sound of a jet plane passing overhead. To supplement the qualitative data received from the community, quantitative noise data was collected at various flaring conditions, wind conditions, and steam rates. Additional...

  10. Unknown: Multifocal scalp hair loss

    E-Print Network [OSTI]

    Shamsadini, Sadollah; Esfandiarpoor, Iraj; Zeinali, Hamid; Kalantari, Behjat; Ebrahimi, Hoseiali

    2006-01-01T23:59:59.000Z

    Unknown: Multifocal scalp hair loss Sadllah Shamsadini 1 ,four patches of scalp hair loss. What is your diagnosis?

  11. Extreme Ultra-Violet Spectroscopy of the Flaring Solar Chromosphere

    E-Print Network [OSTI]

    Milligan, Ryan O

    2015-01-01T23:59:59.000Z

    The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.

  12. Ohio Natural Gas Vented and Flared (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2007 10,998 9,933 10,998 10,643 10,998through 1996) inDecadeDecade (Million CubicDecadeVented and Flared

  13. Arizona Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines AboutDecemberSteam Coal Import CostsLiquidsYear JanYearVented and Flared (Million Cubic

  14. Arizona Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines AboutDecemberSteam Coal Import CostsLiquidsYear JanYearVented and Flared (Million

  15. Florida Natural Gas Vented and Flared (Million Cubic Feet)

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines About U.S.30Natural Gas Glossary529 6330 0 1 0 0 0 1979-2013Fuel2009Vented and Flared

  16. Virginia Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelinesProved ReservesFeet)per Thousand28Decreases (Billion CubicYear7.14Vented and Flared

  17. PLASMA HEATING IN THE VERY EARLY AND DECAY PHASES OF SOLAR FLARES

    SciTech Connect (OSTI)

    Falewicz, R.; Rudawy, P. [Astronomical Institute, University of Wroclaw, 51-622 Wroclaw, ul. Kopernika 11 (Poland); Siarkowski, M., E-mail: falewicz@astro.uni.wroc.pl, E-mail: rudawy@astro.uni.wroc.pl, E-mail: ms@cbk.pan.wroc.pl [Space Research Centre, Polish Academy of Sciences, 51-622 Wroclaw, ul. Kopernika 11 (Poland)

    2011-05-20T23:59:59.000Z

    In this paper, we analyze the energy budgets of two single-loop solar flares under the assumption that non-thermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were observed by RHESSI and GOES on 2002 September 20 and 2002 March 17, respectively. For both investigated flares we derived the energy fluxes contained in NTE beams from the RHESSI observational data constrained by observed GOES light curves. We showed that energy delivered by NTEs was fully sufficient to fulfill the energy budgets of the plasma during the pre-heating and impulsive phases of both flares as well as during the decay phase of one of them. We concluded that in the case of the investigated flares there was no need to use any additional ad hoc heating mechanisms other than heating by NTEs.

  18. Multi-TeV flaring from blazars: Markarian 421 a case study

    E-Print Network [OSTI]

    Sahu, Sarira; Rajpoot, Subhash

    2015-01-01T23:59:59.000Z

    The TeV blazar Markarian 421 underwent multi-TeV flaring during April 2004 and simultaneously observed in x-ray and TeV energies. It was observed that the TeV outbursts had no counterparts in the lower energies, which implies that this might be an orphan flare. In the context of hadronic model, we have shown that this multi-TeV flaring can be produced due to the interaction of Fermi-accelerated protons of energy $\\lesssim 168$ TeV with the background photons in the low energy tail of the synchrotron self-Compton spectrum of the blazar jet. We fit very well the flaring spectrum with this model. Based on this study, we speculate that Mrk 501 and PG 1553+113 are possible candidates for orphan flaring in the future.

  19. RAPID TeV GAMMA-RAY FLARING OF BL LACERTAE

    SciTech Connect (OSTI)

    Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)] [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States)] [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)] [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)] [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)] [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Feng, Q.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)] [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Dumm, J.; Fortson, L. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)] [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)] [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Falcone, A. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Federici, S. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany)] [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Finnegan, G., E-mail: qfeng@purdue.edu, E-mail: cui@purdue.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Collaboration: VERITAS Collaboration; and others

    2013-01-10T23:59:59.000Z

    We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 {+-} 0.6) Multiplication-Sign 10{sup -6} photons m{sup -2} s{sup -1}, roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 {+-} 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 {+-} 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.

  20. Solar X-ray Flare Hazards on the Surface of Mars

    E-Print Network [OSTI]

    David S. Smith; John M. Scalo

    2006-10-03T23:59:59.000Z

    Putative organisms on the Martian surface would be exposed to potentially high doses of ionizing radiation during strong solar X-ray flares. We extrapolate the observed flare frequency-energy release scaling relation to releases much larger than seen so far for the sun, an assumption supported by observations of flares on other solar- and subsolar-mass main sequence stars. We calculate the surficial reprocessed X-ray spectra using a Monte Carlo code we have developed. Biological doses from indirect genome damage are calculated for each parameterized flare spectrum by integration over the X-ray opacity of water. We estimate the mean waiting time for solar flares producing a given biological dose of ionizing radiation on Mars and compare with lethal dose data for a wide range of terrestrial organisms. These timescales range from decades for significant human health risk to 0.5 Myr for D. radiodurans lethality. Such doses require total flare energies of 10^33--10^38 erg, the lower range of which has been observed for other stars. Flares are intermittent bursts, so acute lethality will only occur on the sunward hemisphere during a sufficiently energetic flare, unlike low-dose-rate, extended damage by cosmic rays. We estimate the soil and CO_2 ice columns required to provide 1/e shielding as 4--9 g cm^-2, depending on flare mean energy and atmospheric column density. Topographic altitude variations give a factor of two variation in dose for a given flare. Life in ice layers that may exist ~ 100 g cm^-2 below the surface would be well protected.

  1. THE ROLE OF A FLUX ROPE EJECTION IN A THREE-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATION OF A SOLAR FLARE

    SciTech Connect (OSTI)

    Nishida, Keisuke; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)] [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Nishizuka, Naoto, E-mail: nishida@kwasan.kyoto-u.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-10-01T23:59:59.000Z

    We investigated the dynamic evolution of a three-dimensional (3D) flux rope eruption and magnetic reconnection process in a solar flare by simply extending the two-dimensional (2D) resistive magnetohydrodynamic simulation model of solar flares with low ? plasma to a 3D model. We succeeded in reproducing a current sheet and bi-directional reconnection outflows just below the flux rope during the eruption in our 3D simulations. We calculated four cases of a strongly twisted flux rope and a weakly twisted flux rope in 2D and 3D simulations. The time evolution of a weakly twisted flux rope in the 3D simulation shows behaviors similar to those of the 2D simulation, while a strongly twisted flux rope in the 3D simulation clearly shows a different time evolution from the 2D simulation except for the initial phase evolution. The ejection speeds of both strongly and weakly twisted flux ropes in 3D simulations are larger than in the 2D simulations, and the reconnection rates in 3D cases are also larger than in the 2D cases. This indicates positive feedback between the ejection speed of a flux rope and the reconnection rate even in the 3D simulation, and we conclude that the plasmoid-induced reconnection model can be applied to 3D. We also found that small-scale plasmoids are formed inside a current sheet and make it turbulent. These small-scale plasmoid ejections have a role in locally increasing the reconnection rate intermittently as observed in solar flares, coupled with a global eruption of a flux rope.

  2. Heat loss from an open cavity

    SciTech Connect (OSTI)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01T23:59:59.000Z

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  3. A Comprehensive Study of Gamma-Ray Burst Optical Emission: I. Flares and Early Shallow Decay Component

    E-Print Network [OSTI]

    Li, Liang; Tang, Qing-Wen; Chen, Jie-Min; Xi, Shao-Qiang; LV, Hou-Jun; Zhang, Bing; Zhang, Jin; Yi, Shuang-Xi; Lu, Rui-Jing; LV, Lian-Zhong; Wei, Jian-Yan

    2012-01-01T23:59:59.000Z

    Well-sampled optical lightcurves of 146 GRBs are complied from the literature. Fitting the lightcurves with the superposition of multiple broken power law functions, we identify eight possible emission components that may have distinct physical origins. We summarize the results in a "synthetic" optical lightcurve. In this paper we focus on a statistical analysis of optical flares and an early optical shallow-decay component, both are likely related to a long-term central engine activity. Twenty-four optical flares are obtained from 19 GRBs. The isotropic flare peak luminosity is correlated with that of gamma-rays. The flares peak at from tens of seconds to several days post the GRB trigger. Later flares tend to be wider and dimmer. The fraction of GRBs with detected optical flares is much smaller than that of X-ray flares. Associated X-ray flares are observed for 4 optical flares, and the optical flares usually lag behind the corresponding X-ray flares. An optical shallow decay segment is observed in 39 GRBs....

  4. MULTI-WAVELENGTH OBSERVATIONS OF THE SPATIO-TEMPORAL EVOLUTION OF SOLAR FLARES WITH AIA/SDO. II. HYDRODYNAMIC SCALING LAWS AND THERMAL ENERGIES

    SciTech Connect (OSTI)

    Aschwanden, Markus J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304 (United States); Shimizu, Toshifumi, E-mail: aschwanden@lmsal.com, E-mail: shimizu.toshifumi@isas.jaxa.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-10-20T23:59:59.000Z

    In this study we measure physical parameters of the same set of 155 M- and X-class solar flares observed with AIA/SDO as analyzed in Paper I, by performing a differential emission measure analysis to determine the flare peak emission measure EM{sub p} , peak temperature T{sub p} , electron density n{sub p} , and thermal energy E{sub th}, in addition to the spatial scales L, areas A, and volumes V measured in Paper I. The parameter ranges for M- and X-class flares are log (EM{sub p}) = 47.0-50.5, T{sub p} = 5.0-17.8 MK, n{sub p} = 4 × 10{sup 9}-9 × 10{sup 11} cm{sup –3}, and thermal energies of E{sub th} = 1.6 × 10{sup 28}-1.1 × 10{sup 32} erg. We find that these parameters obey the Rosner-Tucker-Vaiana (RTV) scaling law T{sub p}{sup 2}?n{sub p} L and H?T {sup 7/2} L {sup –2} during the peak time t{sub p} of the flare density n{sub p} , when energy balance between the heating rate H and the conductive and radiative loss rates is achieved for a short instant and thus enables the applicability of the RTV scaling law. The application of the RTV scaling law predicts power-law distributions for all physical parameters, which we demonstrate with numerical Monte Carlo simulations as well as with analytical calculations. A consequence of the RTV law is also that we can retrieve the size distribution of heating rates, for which we find N(H)?H {sup –1.8}, which is consistent with the magnetic flux distribution N(?)??{sup –1.85} observed by Parnell et al. and the heating flux scaling law F{sub H} ?HL?B/L of Schrijver et al.. The fractal-diffusive self-organized criticality model in conjunction with the RTV scaling law reproduces the observed power-law distributions and their slopes for all geometrical and physical parameters and can be used to predict the size distributions for other flare data sets, instruments, and detection algorithms.

  5. RAPID SUNSPOT ROTATION ASSOCIATED WITH THE X2.2 FLARE ON 2011 FEBRUARY 15

    SciTech Connect (OSTI)

    Jiang Yunchun; Zheng Ruisheng; Yang Jiayan; Hong Junchao; Yi Bi; Yang Dan, E-mail: jyc@ynao.ac.cn [National Astronomical Observatory/Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

    2012-01-01T23:59:59.000Z

    We present observations of sunspot evolution associated with the first X-class flare of the present solar cycle 24, which occurred in AR 11158 on 2011 February 15. The active region consisted of four emerging bipoles that showed complicated sunspot motion. The preceding spot of a bipole underwent the fastest movement. It not only passed through the following end of another bipole, thus causing a shearing motion, but also merged with the same-polarity spots and formed a single, larger umbra. This led to the formation of a {delta} configuration with an S-shaped neutral line, above which an extreme ultraviolet filament channel and a sigmoid formed and erupted to produce the flare. Along with the development of a clockwise (CW) spiral penumbra-filament pattern, the merged spot started rapid CW rotation around its umbral center 20 hr before the flare. The rotation persisted throughout the flare but stopped sharply about 1 hr after the flare ended, maintaining the twisted penumbra-filament pattern. The moving spot also caused continuous flux cancellation; in particular, its outer penumbra directly collided with small opposite-polarity spots only 100 minutes before the flare. When the shearing and rotational motions are main contributors to the energy buildup and helicity injection for the flare, the cancellation and collision might act as a trigger. Our observations support the idea that the rotation can be attributed to the emergence of twisted magnetic fields, as proposed in recent theories. Finally, the cause of its sudden halt is discussed.

  6. Dynamics of Electric Currents, Magnetic Field Topology and Helioseismic Response of a Solar Flare

    E-Print Network [OSTI]

    Sharykin, I N

    2015-01-01T23:59:59.000Z

    The solar flare on July 30, 2011 was of a modest X-ray class (M9.3), but it made a strong photospheric impact and produced a "sunquake," observed with the Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamics Observatory (SDO). In addition to the helioseismic waves (also observed with the SDO/AIA instrument), the flare caused a large expanding area of white-light emission and was accompanied by substantial restructuring of magnetic fields, leading to the rapid formation of a sunspot structure in the flare region. The flare produced no significant hard X-ray emission and no coronal mass ejection. This indicates that the flare energy release was mostly confined to the lower atmosphere. The absence of significant coronal mass ejection rules out magnetic rope eruption as a mechanism of helioseismic waves. We discuss the connectivity of the flare energy release with the electric currents dynamics and show the potential importance of high-speed plasma flows in the lower solar atmosphere during the flare e...

  7. The detection of M-dwarf UV flare events in the GALEX data archives

    E-Print Network [OSTI]

    Barry Y. Welsh; Jonathan M. Wheatley; Mark Seibert; Stanley E. Browne; Andrew A. West; Oswald H. W. Siegmund; Tom A. Barlow; Karl Forster; Peter G. Friedman; D. Christopher Martin; Patrick Morrissey; Todd Small; Ted Wyder; David Schiminovich; Susan Neff; R. Michael Rich

    2006-05-12T23:59:59.000Z

    We present the preliminary results from implementing a new software tool that enables inspection of time-tagged photon data for the astronomical sources contained within individual GALEX ultraviolet images of the sky. We have inspected the photon data contained within 1802 GALEX images to reveal rapid, short-term (<500 sec) UV source variability in the form of stellar flares. The mean associated change in NUV magnitude due to this flaring activity is 2.7+/-0.3 mag. A list of 49 new UV variable-star candidates is presented, together with their associated Sloan Digital Sky Survey (SDSS) photometric magnitudes. From these data we can associate the main source of these UV flare events with magnetic activity on M-dwarf stars. Photometric parallaxes have been determined for 32 of these sources, placing them at distances ranging from approximately 25 to 1000pc. The average UV flare energy for these flare events is 2.5E30 ergs, which is of a similar energy to that of U-band, X-ray and EUV flares observed on many local M-dwarf stars. We have found that stars of classes M0 to M5 flare with energies spanning a far larger range and with an energy approximately 5 times greater than those of later (M6 to M8) spectral type.

  8. Simbol-X capability of detecting the non-thermal emission of stellar flares

    E-Print Network [OSTI]

    C. Argiroffi; G. Micela; A. Maggio

    2008-01-16T23:59:59.000Z

    We investigate the capability of detecting, with Simbol-X, non-thermal emission during stellar flares, and distinguishing it from hot thermal emission. We find that flare non-thermal emission is detectable when at least ~20 cts are detected with the CZT detector in the 20-80 keV band. Therefore Simbol-X will detect the non-thermal emission from some of the X-ray brightest nearby stars, whether the thermal vs. non-thermal relation, derived for solar flares, holds.

  9. Regularized energy-dependent solar flare hard x-ray spectral index

    E-Print Network [OSTI]

    Eduard P. Kontar; Alexander L. MacKinnon

    2005-06-05T23:59:59.000Z

    The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency of spectral index for a high resolution energy spectrum provided by Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The regularization technique produces much smoother derivatives while avoiding additional errors typical of finite differences. It is shown that observations imply a spectral index varying significantly with energy, in a way that also varies with time as the flare progresses. The implications of these findings are discussed in the solar flare context.

  10. A NEW CORRELATION BETWEEN GRB X-RAY FLARES AND THE PROMPT EMISSION

    SciTech Connect (OSTI)

    Sonbas, E. [Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey); MacLachlan, G. A.; Shenoy, A.; Dhuga, K. S.; Parke, W. C., E-mail: edasonbas@yahoo.com [Department of Physics, George Washington University, Washington, DC 20052 (United States)

    2013-04-20T23:59:59.000Z

    From a sample of gamma-ray bursts (GRBs) detected by the Fermi and Swift missions, we have extracted the minimum variability timescales for temporal structures in the light curves associated with the prompt emission and X-ray flares. A comparison of this variability timescale with pulse parameters such as rise times, determined via pulse-fitting procedures, and spectral lags, extracted via the cross-correlation function, indicates a tight correlation between these temporal features for both the X-ray flares and the prompt emission. These correlations suggest a common origin for the production of X-ray flares and the prompt emission in GRBs.

  11. SWAP Observations of Post-flare Giant Arches in the Long-Duration 14 October 2014 Solar Eruption

    E-Print Network [OSTI]

    West, Matthew J

    2015-01-01T23:59:59.000Z

    On 14 October 2014 the Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on-board the Project for On-Board Autonomy 2 (PROBA2) spacecraft observed an eruption that led to the formation of perhaps the largest post-eruptive loop system seen in the solar corona in solar cycle 24. The initial eruption occurred at about 18:30 UT on 14 October, behind the East Solar limb, and was observed as a a coronal mass ejection and an M2.2 solar flare. In the 48 hours following the eruption, the associated post-eruptive loops grew to a height of approximately 400000 km (>0.5 solar-radii) at rates between 2-6 km/s. We conclude from our observations of this event that ordinary post-eruptive loops and so-called post-flare giant arches are fundamentally the same and are formed by the same magnetic reconnection mechanism.

  12. X-ray flares from dense shells formed in gamma-ray burst explosions

    E-Print Network [OSTI]

    Hascoet, R; Daigne, F; Mochkovitch, R

    2015-01-01T23:59:59.000Z

    Bright X-ray flares are routinely detected by the Swift satellite during the early afterglow of gamma-ray bursts, when the explosion ejecta drives a blast wave into the external medium. We suggest that the flares are produced as the reverse shock propagates into the tail of the ejecta. The ejecta is expected to contain a few dense shells formed at an earlier stage of the explosion. We show an example of how such dense shells form and describe how the reverse shock interacts with them. A new reflected shock is generated in this interaction, which produces a short-lived X-ray flare. The model provides a natural explanation for the main observed features of the X-ray flares --- the fast rise, the steep power-law decline, and the characteristic peak duration \\Delta t /t= (0.1-0.3).

  13. Catalogue of a Loss

    E-Print Network [OSTI]

    Berger, Larisa (Larisa A.)

    2012-01-01T23:59:59.000Z

    Catalogue of a Loss is a collection of sixty-two prose poems written within the past year and half. The work is printed on 4x6 cards. Each poem may be read individually from a single card or the poems can be read in ...

  14. High-temperature phase transition in a plasma and the mechanism of powerful solar flares

    E-Print Network [OSTI]

    Fedor V. Prigara

    2006-05-04T23:59:59.000Z

    It is shown that the high- temperature phase transition in a plasma gives the mechanism of transition from the highly conductive state to the highly resistive state of a plasma in the `electric circuit' model of solar flares which was first introduced by H.Alfven and P.Carlqvist in 1967. With this addendum, the modern version of the electric circuit model can explain both the fast dissipation of energy and the acceleration of particles in a solar flare.

  15. Study of Two Successive Three-Ribbon Solar Flares on 2012 July 6

    E-Print Network [OSTI]

    Wang, Haimin; Deng, Na; Zeng, Zhicheng; Xu, Yan; Jing, Ju; Cao, Wenda

    2013-01-01T23:59:59.000Z

    This Letter reports two rarely observed three-ribbon flares (M1.9 and C9.2) on 2012 July 6 in NOAA AR 11515, which we found with Halpha observations of 0.1" resolution from the New Solar Telescope and CaII H images from Hinode. The flaring site is characterized with an intriguing "fish-bone-like" morphology evidenced by both Halpha images and a nonlinear force-free field (NLFFF) extrapolation, where two semi-parallel rows of low-lying, sheared loops connect an elongated, parasitic negative field with the sandwiching positive fields. The NLFFF model also shows that the two rows of loops are asymmetric in height and have opposite twists, and are enveloped by large-scale field lines including open fields. The two flares occurred in succession in half an hour and are located at the two ends of the flaring region. The three ribbons of each flare run parallel to the PIL, with the outer two lying in the positive field and the central one in the negative field. Both flares show surge-like flows in Halpha apparently t...

  16. Plasma Heating to Super-Hot Temperatures (>30 MK) in the August 9, 2011 Solar Flare

    E-Print Network [OSTI]

    Sharykin, I N; Zimovets, I V

    2015-01-01T23:59:59.000Z

    We investigate the August 9, 2011 solar flare of X-ray class X6.9, the "hottest" flare from 2000 to 2012, with a peak plasma temperature according to GOES data of 32.5 MK. Our goal is to determine the cause of such an anomalously high plasma temperature and to investigate the energy balance in the flare region with allowance made for the presence of a super-hot plasma (>30 MK). We analyze the RHESSI, GOES, AIA/SDO, and EVE/SDO data and discuss the spatial structure of the flare region and the results of our spectral analysis of its X-ray emission. Our analysis of the RHESSI X-ray spectra is performed in the one-temperature and two-temperature approximations by taking into account the emission of hot (20 MK) and super-hot (45 MK) plasmas. The hard X-ray spectrum in both models is fitted by power laws. The observed peculiarities of the flare are shown to be better explained in terms of the two-temperature model, in which the super-hot plasma is located at the flare loop tops (or in the magnetic cusp region). Th...

  17. 2 Solar flare signatures of the ionospheric GPS total electron content 3 J. Y. Liu,1,2

    E-Print Network [OSTI]

    Chen, Yuh-Ing

    2 Solar flare signatures of the ionospheric GPS total electron content 3 J. Y. Liu,1,2 C. H. Lin,1, ionospheric solar flare effects on the total electron content (TEC) and 7 associated time rate of change (r. The occurrence times and 9 locations of 11 solar flares are isolated from the 1­8 A° X-ray radiations of the 10

  18. Full Stokes observations in the He I 1083 nm spectral region covering an M3.2 flare

    E-Print Network [OSTI]

    Kuckein, C; Sainz, R Manso; Ramos, A Asensio

    2015-01-01T23:59:59.000Z

    We present an exceptional data set acquired with the Vacuum Tower Telescope (Tenerife, Spain) covering the pre-flare, flare, and post-flare stages of an M3.2 flare. The full Stokes spectropolarimetric observations were recorded with the Tenerife Infrared Polarimeter in the He I 1083.0 nm spectral region. The object under study was active region NOAA 11748 on 2013 May 17. During the flare the chomospheric He I 1083.0 nm intensity goes strongly into emission. However, the nearby photospheric Si I 1082.7 nm spectral line profile only gets shallower and stays in absorption. Linear polarization (Stokes Q and U) is detected in all lines of the He I triplet during the flare. Moreover, the circular polarization (Stokes V) is dominant during the flare, being the blue component of the He I triplet much stronger than the red component, and both are stronger than the Si I Stokes V profile. The Si I inversions reveal enormous changes of the photospheric magnetic field during the flare. Before the flare magnetic field conc...

  19. The evolution of the width of X-ray flares with time in Gamma-ray bursts

    SciTech Connect (OSTI)

    Bernardini, Maria Grazia [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); ICRANet, P.le della Repubblica 10, I-65100 Pescara (Italy); Chincarini, Guido; Margutti, Raffaella [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); University of Milano Bicocca, Physics Dept., P.zza della Scienza 3, I-20126 Milano (Italy)

    2010-10-15T23:59:59.000Z

    We present one of the most intriguing results obtained with an updated catalog of 113 early time (i.e. t{sub pk} < or approx. 1000 s) and 36 late time (i.e. t{sub pk} > or approx. 1000 s) X-ray flares detected by Swift in the afterglows of Gamma-Ray Bursts (GRB): the evolution of the width of the flares with time. This result, together with other properties investigated on early and late time flares and bright flares, provides a clear observational property that every model aiming at explaining the GRB emission has to face.

  20. CONTINUUM CONTRIBUTIONS TO THE SDO/AIA PASSBANDS DURING SOLAR FLARES

    SciTech Connect (OSTI)

    Milligan, Ryan O.; McElroy, Sarah A., E-mail: r.milligan@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2013-11-01T23:59:59.000Z

    Data from the Multiple EUV Grating Spectrograph component of the Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) were used to quantify the contribution of continuum emission to each of the extreme ultraviolet (EUV) channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during an X-class solar flare that occurred on 2011 February 15. Both the pre-flare-subtracted EVE spectra and fits to the associated free-free continuum were convolved with the AIA response functions of the seven EUV passbands at 10 s cadence throughout the course of the flare. It was found that 10%-25% of the total emission in the 94 Å, 131 Å, 193 Å, and 335 Å passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171 Å channel, while the continuum contribution to the 304 Å channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211 Å channel was found to be due to free-free emission around the peak of the flare, while an additional 20% was due to the recombination continuum of He II. The analysis was extended to a number of M- and X-class flares and it was found that the level of free-free emission contributing to both the 171 Å and 211 Å passbands increased with increasing GOES class. These results suggest that the amount of continuum emission that contributes to AIA observations during flares is more significant than stated in previous studies which used synthetic, rather than observed, spectra. These findings highlight the importance of spectroscopic observations carried out in conjunction with those from imaging instruments so that the data are interpreted correctly.

  1. High resolution gamma ray spectroscopy of flares on the east and west limbs of the Sun

    E-Print Network [OSTI]

    M. J. Harris; V. Tatischeff; J. Kiener; M. Gros; G. Weidenspointner

    2006-10-29T23:59:59.000Z

    A new generation of Ge-based high-resolution gamma-ray spectrometers has allowed accurate measurements to be made of the profiles, widths and energies of the gamma-ray lines emitted in the impulsive phases of solar flares. Here we present measurements in two flares of the energies of the de-excitation lines of 12C and 16O at 4.4 and 6.1 MeV respectively by the Ge spectrometer SPI on board INTEGRAL, from which Doppler shifts are derived and compared with those expected from the recoil of 12C and 16O nuclei which were excited by the impacts of flare-accelerated ions. An anomalous Doppler measurement (in terms of recoil theory) has been reported by the Ge spectrometer RHESSI in a flare near the east limb, and explained by a tilt of the magnetic field lines at the footpoint of a magnetic loop away from the vertical, and towards the observer. This might be interpreted to imply a significant difference between the Doppler shifts on the east and west limbs, if it is a general phenomenon. SPI observed both east and west limb flares and found no significant difference in Doppler shifts. We also measured the shapes and fluences of these lines, and their fluence ratio to the 2.2 MeV line from the capture of flare-generated neutrons. Analyses of both quantities using thick-target models parametrized by solar physical and geometric quantities suggest that the two flares studied here also have magnetic fields tilted towards the observer, though the significance of the measurements is not high.

  2. High-sensitivity observations of solar flare decimeter radiation

    E-Print Network [OSTI]

    Arnold O. Benz; Peter Messmer; Christian Monstein

    2000-12-05T23:59:59.000Z

    A new acousto-optic radio spectrometer has observed the 1 - 2 GHz radio emission of solar flares with unprecedented sensitivity. The number of detected decimeter type III bursts is greatly enhanced compared to observations by conventional spectrometers observing only one frequency at the time. The observations indicate a large number of electron beams propagating in dense plasmas. For the first time, we report weak, reversed drifting type III bursts at frequencies above simultaneous narrowband decimeter spikes. The type III bursts are reliable signatures of electron beams propagating downward in the corona, apparently away from the source of the spikes. The observations contradict the most popular spike model that places the spike sources at the footpoints of loops. Conspicuous also was an apparent bidirectional type U burst forming a fish-like pattern. It occurs simultaneously with an intense U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated with strong terrestrial interference (cellular phones) causing a spurious symmetric pattern in the spectrogram at 1.4 GHz. Symmetric features in the 1 - 2 GHz range, some already reported in the literature, therefore must be considered with utmost caution.

  3. Soot and SO[subscript 2] contribution to the supersites in the MILAGRO campaign from elevated flares in the Tula Refinery

    E-Print Network [OSTI]

    Molina, Luisa Tan

    This work presents a simulation of the plume trajectory emitted by flaring activities of the Miguel Hidalgo Refinery in Mexico. The flame of a representative sour gas flare is modeled with a CFD combustion code in order ...

  4. Optical Spectral Observations of a Flickering White-Light Kernel in a C1 Solar Flare

    E-Print Network [OSTI]

    Kowalski, Adam F; Fletcher, Lyndsay

    2014-01-01T23:59:59.000Z

    We analyze optical spectra of a two-ribbon, long duration C1.1 flare that occurred on 18 Aug 2011 within AR 11271 (SOL2011-08-18T15:15). The impulsive phase of the flare was observed with a comprehensive set of space-borne and ground-based instruments, which provide a range of unique diagnostics of the lower flaring atmosphere. Here we report the detection of enhanced continuum emission, observed in low-resolution spectra from 3600 \\AA\\ to 4550 \\AA\\ acquired with the Horizontal Spectrograph at the Dunn Solar Telescope. A small, $\\le$0''.5 ($10^{15}$ cm$^2$) penumbral/umbral kernel brightens repeatedly in the optical continuum and chromospheric emission lines, similar to the temporal characteristics of the hard X-ray variation as detected by the Gamma-ray Burst Monitor (GBM) on the Fermi spacecraft. Radiative-hydrodynamic flare models that employ a nonthermal electron beam energy flux high enough to produce the optical contrast in our flare spectra would predict a large Balmer jump in emission, indicative of h...

  5. The Confined X-class Flares of Solar Active Region 2192

    E-Print Network [OSTI]

    Thalmann, J K; Temmer, M; Veronig, A M

    2015-01-01T23:59:59.000Z

    The unusually large NOAA active region 2192, observed in October 2014, was outstanding in its productivity of major two-ribbon flares without coronal mass ejections. On a large scale, a predominantly north-south oriented magnetic system of arcade fields served as a strong, also lateral, confinement for a series of large two-ribbon flares originating from the core of the active region. The large initial separation of the flare ribbons, together with an almost absent growth in ribbon separation, suggests a confined reconnection site high up in the corona. Based on a detailed analysis of the confined X1.6 flare on October 22, we show how exceptional the flaring of this active region was. We provide evidence for repeated energy release, indicating that the same magnetic field structures were repeatedly involved in magnetic reconnection. We find that a large number of electrons was accelerated to non-thermal energies, revealing a steep power law spectrum, but that only a small fraction was accelerated to high ener...

  6. PRIOR FLARING AS A COMPLEMENT TO FREE MAGNETIC ENERGY FOR FORECASTING SOLAR ERUPTIONS

    SciTech Connect (OSTI)

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F. [ZP13 MSFC/NASA, Huntsville, AL 35812 (United States); Khazanov, Igor [CSPAR, Cramer Hall/NSSTC, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2012-09-20T23:59:59.000Z

    From a large database of (1) 40,000 SOHO/MDI line-of-sight magnetograms covering the passage of 1300 sunspot active regions across the 30 Degree-Sign radius central disk of the Sun, (2) a proxy of each active region's free magnetic energy measured from each of the active region's central-disk-passage magnetograms, and (3) each active region's full-disk-passage history of production of major flares and fast coronal mass ejections (CMEs), we find new statistical evidence that (1) there are aspects of an active region's magnetic field other than the free energy that are strong determinants of the active region's productivity of major flares and fast CMEs in the coming few days; (2) an active region's recent productivity of major flares, in addition to reflecting the amount of free energy in the active region, also reflects these other determinants of coming productivity of major eruptions; and (3) consequently, the knowledge of whether an active region has recently had a major flare, used in combination with the active region's free-energy proxy measured from a magnetogram, can greatly alter the forecast chance that the active region will have a major eruption in the next few days after the time of the magnetogram. The active-region magnetic conditions that, in addition to the free energy, are reflected by recent major flaring are presumably the complexity and evolution of the field.

  7. Could the Wein fireball be associated to the "orphan" TeV flares ?

    E-Print Network [OSTI]

    Fraija, Nissim

    2015-01-01T23:59:59.000Z

    TeV $\\gamma$-ray detections in flaring states without activity in X-rays from blazars have attracted much attention due to the irregularity of these "orphan" flares. Although the synchrotron self-Compton model has been very successful in explaining the spectral energy distribution and spectral variability of these sources, it has not been able to describe these atypical flaring events. On the other hand, an electron-positron pair plasma at the base of the AGN jet was proposed as the mechanism of bulk acceleration of relativistic outflows. This plasma in quasi-themal equilibrium called Wein fireball emits radiation at MeV-peak energies serving as target of accelerated protons. In this work we describe the "orphan" TeV flares presented in blazars 1ES 1959+650 and Mrk421 assuming geometrical considerations in the jet and evoking the interactions of Fermi-accelerated protons and MeV-peak target photons coming from the Wein fireball. After describing successfully these "orphan" TeV flares, we correlate the TeV $\\g...

  8. An explanation for long flares from extragalactic globular cluster X-ray sources

    E-Print Network [OSTI]

    Thomas J. Maccarone

    2005-09-21T23:59:59.000Z

    Repeatedly flaring X-ray binaries have recently been discovered in NGC 4697 by Sivakoff and collaborators. We show that these flares can be explained as the result of eccentric binaries in globular clusters which accrete more rapidly at periastron than during the rest of the binary orbit. We show that theoretical timescales for producing eccentricities and circularising the binaries are consistent with what is needed to produce the observed population of flaring sources, although the circularisation timescales are highly uncertain on both observational and theoretical grounds. This model makes two clear theoretical predictions (1) the flares should be seen to be strictly periodic if adequate sampling is provided, and that periodicity should be of approximately 15 hours (2) this class of flaring behaviour should be seen only in globular cluster sources, and predominantly in the densest globular clusters. We also test the model for producing eccentricities through fly-by's of a third star near the binary in a globular cluster against a much larger database of millisecond pulsar observations than has been used in past work, and find that the theoretical cross sections for producing eccentricity in binaries are in reasonable agreement with most of the data, provided that the pulsar ages are about $4\\times10^9$ years.

  9. Solar Flare Element Abundances from the Solar Assembly for X-rays (SAX) on MESSENGER

    E-Print Network [OSTI]

    Dennis, B R; Schwartz, R A; Tolbert, A K; Starr, R D; Nittler, L R

    2015-01-01T23:59:59.000Z

    X-ray spectra in the range $1.5-8.5$~keV have been analyzed for 526 large flares detected with the Solar Assembly for X-rays (SAX) on the Mercury {\\em MESSENGER} spacecraft between 2007 and 2013. For each flare, the temperature and emission measure of the emitting plasma were determined from the spectrum of the continuum. In addition, with the SAX energy resolution of 0.6 keV (FWHM) at 6~keV, the intensities of the clearly resolved Fe-line complex at 6.7~keV and the Ca-line complex at 3.9~keV were determined, along with those of unresolved line complexes from S, Si, and Ar at lower energies. Comparisons of these line intensities with theoretical spectra allow the abundances of these elements relative to hydrogen to be derived, with uncertainties due to instrument calibration and the unknown temperature distribution of the emitting plasma. While significant deviations are found for the abundances of Fe and Ca from flare to flare, the abundances averaged over all flares are found to be enhanced over photospheri...

  10. X-ray flares, neutrino cooled disks, and the dynamics of late accretion in GRB engines

    E-Print Network [OSTI]

    Davide Lazzati; Rosalba Perna; Mitchell C. Begelman

    2008-05-01T23:59:59.000Z

    We compute the average luminosity of X-ray flares as a function of time, for a sample of 10 long-duration gamma-ray burst afterglows. The mean luminosity, averaged over a timescale longer than the duration of the individual flares, declines as a power-law in time with index ~-1.5. We elaborate on the properties of the central engine that can produce such a decline. Assuming that the engine is an accreting compact object, and for a standard conversion factor between accretion rate and jet luminosity, the switch between a neutrino-cooled thin disk and a non-cooled thick disk takes place at the transition from the prompt to the flaring phase. We discuss the implications of this coincidence under different scenarios for the powering of the GRB outflow. We also show that the interaction of the outflow with the envelope of the progenitor star cannot produce flares out of a continuous relativistic flow, and conclude that it is the dynamics of the disk or the jet-launching mechanism that generates an intrinsically unsteady outflow on timescales much longer than the dynamical timescale of the system. This is consistent with the fact that X-ray flares are observed in short-duration GRBs as well as in long-duration ones.

  11. FLARE-GENERATED TYPE II BURST WITHOUT ASSOCIATED CORONAL MASS EJECTION

    SciTech Connect (OSTI)

    Magdalenic, J.; Marque, C.; Zhukov, A. N. [Solar-Terrestrial Center of Excellence, SIDC, Royal Observatory of Belgium, Avenue Circulaire 3, B-1180 Brussels (Belgium); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, Kaciceva 26, HR-10000 Zagreb (Croatia); Veronig, A., E-mail: Jasmina.Magdalenic@oma.be [IGAM/Kanzelhoehe Observatory, Institut of Physics, Universitaet Graz, Universitaetsplatz 5, A-8010 Graz (Austria)

    2012-02-20T23:59:59.000Z

    We present a study of the solar coronal shock wave on 2005 November 14 associated with the GOES M3.9 flare that occurred close to the east limb (S06 Degree-Sign E60 Degree-Sign ). The shock signature, a type II radio burst, had an unusually high starting frequency of about 800 MHz, indicating that the shock was formed at a rather low height. The position of the radio source, the direction of the shock wave propagation, and the coronal electron density were estimated using Nancay Radioheliograph observations and the dynamic spectrum of the Green Bank Solar Radio Burst Spectrometer. The soft X-ray, H{alpha}, and Reuven Ramaty High Energy Solar Spectroscopic Imager observations show that the flare was compact, very impulsive, and of a rather high density and temperature, indicating a strong and impulsive increase of pressure in a small flare loop. The close association of the shock wave initiation with the impulsive energy release suggests that the impulsive increase of the pressure in the flare was the source of the shock wave. This is supported by the fact that, contrary to the majority of events studied previously, no coronal mass ejection was detected in association with the shock wave, although the corresponding flare occurred close to the limb.

  12. Turbulence in the Solar Atmosphere: Manifestations and Diagnostics via Solar Image Processing

    E-Print Network [OSTI]

    Manolis K. Georgoulis

    2005-11-15T23:59:59.000Z

    Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of solar magnetic fields. While these techniques advance our understanding of the physical system at work, it is unclear whether they can be used to predict solar eruptions, thus obtaining a practical significance for space weather. We address part of this problem by focusing on solar active regions and by investigating the usefulness of scaling and multi-scaling image-processing techniques in solar flare prediction. Since solar flares exhibit spatial and temporal intermittency, we suggest that they are the products of instabilities subject to a critical threshold in a turbulent magnetic configuration. The identification of this threshold in scaling and multi-scaling spectra would then contribute meaningfully to the prediction of solar flares. We find that the fractal dimension of solar magnetic fields and their multi-fractal spectrum of generalized correlation dimensions do not have significant predictive ability. The respective multi-fractal structure functions and their inertial-range scaling exponents, however, probably provide some statistical distinguishing features between flaring and non-flaring active regions. More importantly, the temporal evolution of the above scaling exponents in flaring active regions probably shows a distinct behavior starting a few hours prior to a flare and therefore this temporal behavior may be practically useful in flare prediction. The results of this study need to be validated by more comprehensive works over a large number of solar active regions.

  13. ELECTRON FLUX SPECTRAL IMAGING OF SOLAR FLARES THROUGH REGULARIZED ANALYSIS OF HARD X-RAY SOURCE VISIBILITIES

    E-Print Network [OSTI]

    Piana, Michele

    ELECTRON FLUX SPECTRAL IMAGING OF SOLAR FLARES THROUGH REGULARIZED ANALYSIS OF HARD X-RAY SOURCE a new method for imaging spectroscopy analysis of hard X-ray emission during solar flares. The method.e., the two-dimensional spatial Fourier transforms of the spectral image) to obtain smoothed (regularized

  14. Detection of Li i enhancement during a longduration flare in the recenltly discovered Xray/EUV selected, chromospher

    E-Print Network [OSTI]

    Complutense de Madrid, Universidad

    of this behavior as an unusual long­duration flare. ­ 1) The temporal evolution of the event is similar to the observed in other solar and stellar flares, with an initial impulsive phase characterized by a strong of the event. A two Gaussian components fit to the subtracted spectra is displayed in the right panel of Fig. 1

  15. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Refinements to flare energy estimates -a follow-up to "Energy

    E-Print Network [OSTI]

    California at Berkeley, University of

    flare/CME events, using as much reliable data as was available, not only on radiative output, but also estimates - a follow-up to "Energy Partition in Two Solar Flare/CME Events" A. G. Emslie, 1 B. R. Dennis 2 in the different flare and CME components of two major solar events with unprecedented observational coverage, one

  16. Long term flaring activity of XRF 011030 observed with BeppoSAX

    E-Print Network [OSTI]

    Piro, A G L

    2005-01-01T23:59:59.000Z

    We present the spectral and temporal analysis of the X-ray flash XRF 011030 observed with BeppoSAX. This event is characterized by a very long X-ray bursting activity that lasts about 1500 s, the longest ever observed by BeppoSAX. In particular a precursor and a late flare are present in the light curve. We connect the late X-ray flare observed at about 1300 s to the afterglow emission observed by Chandra and associate it with the onset of the afterglow emission in the framework of external shock by a long duration engine activity. We find that the late X-ray flare and the broad-band afterglow data, including optical and radio measurements, are consistent either with a fireball expanding in a wind environment or with a jetted fireball in a ISM.

  17. Gamma-ray flares in the Crab Nebula: A case of relativistic reconnection?

    SciTech Connect (OSTI)

    Cerutti, B., E-mail: bcerutti@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Werner, G. R., E-mail: greg.werner@colorado.edu; Uzdensky, D. A., E-mail: uzdensky@colorado.edu [Center for Integrated Plasma Studies, Physics Department, University of Colorado, UCB 390, Boulder, Colorado 80309-0390 (United States); Begelman, M. C., E-mail: mitch@jila.colorado.edu [JILA, University of Colorado and National Institute of Standards and Technology, UCB 440, Boulder, Colorado 80309-0440 (United States)

    2014-05-15T23:59:59.000Z

    The Crab Nebula was formed after the collapse of a massive star about a thousand years ago, leaving behind a pulsar that inflates a bubble of ultra-relativistic electron-positron pairs permeated with magnetic field. The observation of brief but bright flares of energetic gamma rays suggests that pairs are accelerated to PeV energies within a few days; such rapid acceleration cannot be driven by shocks. Here, it is argued that the flares may be the smoking gun of magnetic dissipation in the Nebula. Using 2D and 3D particle-in-cell simulations, it is shown that the observations are consistent with relativistic magnetic reconnection, where pairs are subject to strong radiative cooling. The Crab flares may highlight the importance of relativistic magnetic reconnection in astrophysical sources.

  18. Modeling Non-Confined Coronal Flares: Dynamics and X-Ray Diagnostics

    E-Print Network [OSTI]

    F. Reale; F. Bocchino; G. Peres

    2001-12-14T23:59:59.000Z

    Long-lasting, intense, stellar X-ray flares may approach conditions of breaking magnetic confinement and evolving in open space. We explore this hypothesis with hydrodynamic simulations of flares occurring in a non-confined corona: model flares are triggered by a transient impulsive heating injected in a plane-parallel stratified corona. The plasma evolution is described by means of a numerical 2-D model in cylindrical geometry R,Z. We explore the space of fundamental parameters. As a reference model, we consider a flare triggered by a heating pulse that would cause a 20 MK flare if delivered in a 40000 km long closed loop. The modeled plasma evolution is described. The X-ray emission, spectra and light curves at the ASCA/SIS focal plan, and in two intense X-ray lines (Mg XI at 9.169 A and Fe XXI at 128.752 A), have been synthesized from the models. The results are discussed and compared to features of confined events, and scaling laws are derived. The light curves invariably show a very rapid rise, a constant phase as long as the constant heating is on, and then a very fast decay, on time scales of few seconds, followed by a more gradual one (few minutes). We show that this evolution of the emission, and especially the fast decay, together with other potentially observable effects, are intrinsic to the assumption of non-confinement. Their lack indicates that observed long-lasting stellar X-ray flares should involve plasma strongly confined by magnetic fields.

  19. VERITAS OBSERVATIONS OF DAY-SCALE FLARING OF M 87 IN 2010 APRIL

    SciTech Connect (OSTI)

    Aliu, E.; Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Bradbury, S. M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Duke, C. [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); Falcone, A., E-mail: cmhui@physics.utah.edu [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); and others

    2012-02-20T23:59:59.000Z

    VERITAS has been monitoring the very-high-energy (VHE; > 100 GeV) gamma-ray activity of the radio galaxy M 87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 {+-} 0.16) Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 {+-} 0.68) Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} for E > 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90{sup +0.22}{sub -0.15} days. The shortest detected exponential rise time is three times as long, at 2.87{sup +1.65}{sub -0.99} days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 {+-} 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region.

  20. OCCULTATION OF THE QUIESCENT EMISSION FROM Sgr A* BY IR FLARES

    SciTech Connect (OSTI)

    Yusef-Zadeh, F. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Wardle, M. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Bushouse, H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dowell, C. D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Roberts, D. A. [Adler Planetarium and Astronomy Museum, 1300 South Lake Shore Drive, Chicago, IL 60605 (United States)

    2010-11-20T23:59:59.000Z

    We have investigated the nature of flare emission from Sgr A* during multi-wavelength observations of this source that took place in 2004, 2005, and 2006. We present evidence for dimming of submillimeter and radio flux during the peak of near-IR flares. This suggests that the variability of Sgr A* across its wavelength spectrum is phenomenologically related. The model explaining this new behavior of flare activity could be consistent with adiabatically cooling plasma blobs that are expanding but also partially eclipsing the background quiescent emission from Sgr A*. When a flare is launched, the plasma blob is most compact and is brightest in the optically thin regime whereas the emission in radio/submillimeter wavelengths has a higher opacity. Absorption in the observed light curve of Sgr A* at radio/submillimeter flux is due to the combined effects of lower brightness temperature of plasma blobs with respect to the quiescent brightness temperature and high opacity of plasma blobs. This implies that plasma blobs are mainly placed in the magnetosphere of a disk-like flow or further out in the flow. The depth of the absorption being larger in submillimeter than in radio wavelengths implies that the intrinsic size of the quiescent emission increases with increasing wavelength which is consistent with previous size measurements of Sgr A*. Lastly, we believe that occultation of the quiescent emission of Sgr A* at radio/submillimeter by IR flares can be used as a powerful tool to identify flare activity at its earliest phase of its evolution.

  1. Search for correlations between solar flares and decay rate of radioactive nuclei

    E-Print Network [OSTI]

    E. Bellotti; C. Broggini; G. Di Carlo; M. Laubenstein; R. Menegazzo

    2013-02-05T23:59:59.000Z

    The deacay rate of three different radioactive sources 40K, 137Cs and natTh has been measured with NaI and Ge detectors. Data have been analyzed to search for possible variations in coincidence with the two strongest solar flares of the years 2011 and 2012. No significant deviations from standard expectation have been observed, with a few 10-4 sensitivity. As a consequence, we could not find any effect like that recently reported by Jenkins and Fischbach: a few per mil decrease in the decay rate of 54Mn during solar flares in December 2006.

  2. Do flares in Sagittarius A* reflect the last stage of tidal capture?

    E-Print Network [OSTI]

    A. Cadez; M. Calvani; A. Gomboc; U. Kostic

    2007-09-03T23:59:59.000Z

    In recent years the case for the presence of 3-4 10^6 M_sun black hole in our Galactic Center has gained strength from results of stellar dynamics observations and from the detection of several rapid X-ray and IR flares observed in the Sagittarius A* from 2000 to 2004. Here we explore the idea that such flares are produced when the central black hole tidally captures and disrupts a small body - e.g. a comet or an asteroid.

  3. Lag-luminosity relation in gamma-ray burst X-ray flares

    SciTech Connect (OSTI)

    Margutti, R.

    2010-10-15T23:59:59.000Z

    In strict analogy to prompt pulses, X-ray flares observed by Swift-XRT in long Gamma-Ray Bursts define a lag-luminosity relation: L{sub p,iso}{sup 0.3-10} k{sup eV} {infinity}t{sub lag}{sup -0.95{+-}0.23}. The lag-luminosity is proven to be a fundamental law extending {approx}5 decades in time and {approx}5 in energy. This is direct evidence that GRB X-ray flares and prompt gamma-ray pulses are produced by the same mechanism.

  4. THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES-IMPLICATIONS FOR ELECTRON ACCELERATION MODELS

    SciTech Connect (OSTI)

    Guo, Jingnan [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, D-24118, Kiel (Germany)] [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, D-24118, Kiel (Germany); Emslie, A. Gordon [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States)] [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States); Piana, Michele, E-mail: guo@physik-uni.kiel.de, E-mail: piana@dima.unige.it, E-mail: emslieg@wku.edu [Dipartimento di Matematica, Universita di Genova, via Dodecaneso 35, I-16146 Genova (Italy)] [Dipartimento di Matematica, Universita di Genova, via Dodecaneso 35, I-16146 Genova (Italy)

    2013-03-20T23:59:59.000Z

    We analyze electron flux maps based on RHESSI hard X-ray imaging spectroscopy data for a number of extended coronal-loop flare events. For each event, we determine the variation of the characteristic loop length L with electron energy E, and we fit this observed behavior with models that incorporate an extended acceleration region and an exterior 'propagation' region, and which may include collisional modification of the accelerated electron spectrum inside the acceleration region. The models are characterized by two parameters: the plasma density n in, and the longitudinal extent L{sub 0} of, the acceleration region. Determination of the best-fit values of these parameters permits inference of the volume that encompasses the acceleration region and of the total number of particles within it. It is then straightforward to compute values for the emission filling factor and for the specific acceleration rate (electrons s{sup -1} per ambient electron above a chosen reference energy). For the 24 events studied, the range of inferred filling factors is consistent with a value of unity. The inferred mean value of the specific acceleration rate above E{sub 0} = 20 keV is {approx}10{sup -2} s{sup -1}, with a 1{sigma} spread of about a half-order-of-magnitude above and below this value. We compare these values with the predictions of several models, including acceleration by large-scale, weak (sub-Dreicer) fields, by strong (super-Dreicer) electric fields in a reconnecting current sheet, and by stochastic acceleration processes.

  5. Loan Loss Reserve Fund Impacts on Standard Residential Underwriting Guidelines

    Broader source: Energy.gov [DOE]

    State and local governments can use loan loss reserve (LLR) funds to persuade lenders to offer more flexible terms during the underwriting process. The availability of an LLR can have the following...

  6. Tax aspects of casualty losses

    E-Print Network [OSTI]

    Lehmann, August Herman

    1960-01-01T23:59:59.000Z

    sudden, unex- 1 pected or unusual nature. The word also signifies an accident, a mishap, or some sudden invasion by a hostile agency. It excludes the progressive deterioration of property through a steadily operating cause, and the loss of an article.... F. T, R. 432, rulings and Court decisions indicate that there may be a tendency to dis- regard suddenness as a requirement for a casualty loss deduction. The casualty loss deduction is allowed only for the loss of pro- 3 perty and the property...

  7. GEOMAGNETIC CONSEQUENCES OF THE SOLAR FLARES DURING THE LAST HALE SOLAR CYCLE (II)

    E-Print Network [OSTI]

    GEOMAGNETIC CONSEQUENCES OF THE SOLAR FLARES DURING THE LAST HALE SOLAR CYCLE (II) Georgeta Maris@aira.astro.ro ABSTRACT/RESUME The effects of the solar energetic phenomena cover the entire terrestrial environment, from is the solar plasma that may originate from solar eruptive phenomena that take their energy from magnetic field

  8. The use of electron maps to constrain some physical properties of solar flares

    E-Print Network [OSTI]

    Piana, Michele

    The use of electron maps to constrain some physical properties of solar flares A. M. Massone1 and M Energy Solar Spectroscopic Imager (RHESSI) is a set of Fourier components of the X-ray radiation sam, Italy #12;­ 2 ­ According to a rough classification, two typologies of inverse problems in astronomy can

  9. THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES IMPLICATIONS

    E-Print Network [OSTI]

    Piana, Michele

    THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES ­ IMPLICATIONS FOR ELECTRON spectrum inside the acceleration region. The models are characterized by two parameters: the plasma density@dima.unige.it #12;­ 2 ­ 1. Introduction The Ramaty High Energy Solar Spectroscopic Imager (RHESSI, Lin et al. 2002

  10. LETTER Earth Planets Space, 61, 577580, 2009 Flares and the chromosphere

    E-Print Network [OSTI]

    Hudson, Hugh

    LETTER Earth Planets Space, 61, 577­580, 2009 Flares and the chromosphere Hugh S. Hudson1 limited to the "semi-empirical" models, based on 1D radiative-transfer physics. Such an approach omits dy energetics (Section 2), en- ergy build-up (Section 3), and energy release (Section 4), attempting to use

  11. Accretion, fluorescent X-ray emission and flaring magnetic structures in YSOs

    E-Print Network [OSTI]

    F. Favata

    2004-12-20T23:59:59.000Z

    I present some recent developments on high-energy phenomena in YSOs, concentrating on the new evidence for accretion-induced X-ray emission in YSOs, for Fe 6.4 keV fluorescent emission from the disks of YSOs and for very long magnetic structures responsible for intense X-ray flares, likely connecting the star and the circumstellar disk.

  12. Optofluidic tunable microlens by manipulating the liquid meniscus using a flared microfluidic structure

    E-Print Network [OSTI]

    two different fluids: CaCl2 solution and air. A constant contact angle of 90° is the pivotal factor resulting in the outward bowing and convex shape of the CaCl2 solution-air interface. The contact angle at the CaCl2 solution-air inter- face is maintained by a flared structure in the polydimethylsiloxane

  13. The Sun as an X-ray Star: III. Flares F. Reale, G. Peres

    E-Print Network [OSTI]

    distribution vs. temperature and its evolution during some selected solar ares, representative of the wideThe Sun as an X-ray Star: III. Flares F. Reale, G. Peres Dip. di Scienze Fisiche & Astronomiche class C5.8) to very intense ones (X9) are selected as representative of the aring Sun. The emission

  14. CHARGE-EXCHANGE LIMITS ON LOW-ENERGY {alpha}-PARTICLE FLUXES IN SOLAR FLARES

    SciTech Connect (OSTI)

    Hudson, H. S. [SSL, UC Berkeley, CA 94720 (United States); Fletcher, L.; MacKinnon, A. L. [School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Woods, T. N., E-mail: hhudson@ssl.berkeley.edu [Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Dr., Boulder, CO 80303 (United States)

    2012-06-20T23:59:59.000Z

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Ly{alpha} line of He II at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary {alpha} particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He II bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment on board the Solar Dynamics Observatory gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV nucleon{sup -1}. We study 10 events in total, including the {gamma}-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic particles. The absence of charge-exchange line wings may point to a need for more complete theoretical work. Some of the events do have broadband signatures, which could correspond to continua from other origins, but these do not have the spectral signatures expected from the Orrall-Zirker mechanism.

  15. THE 5 GHz ARECIBO SEARCH FOR RADIO FLARES FROM ULTRACOOL DWARFS

    SciTech Connect (OSTI)

    Route, Matthew; Wolszczan, Alexander, E-mail: mroute@astro.psu.edu, E-mail: alex@astro.psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2013-08-10T23:59:59.000Z

    We present the results of a 4.75 GHz survey of 33 brown dwarfs and one young exoplanetary system for flaring radio emission, conducted with the 305 m Arecibo radio telescope. The goal of this program was to detect and characterize the magnetic fields of objects cooler than spectral type L3.5, the coolest brown dwarf detected prior to our survey. We have also attempted to detect flaring radio emission from the HR 8799 planetary system, guided by theoretical work indicating that hot, massive exoplanets may have strong magnetic fields capable of generating radio emission at GHz frequencies. We have detected and confirmed radio flares from the T6.5 dwarf 2MASS J10475385+2124234. This detection dramatically extends the temperature range over which brown dwarfs appear to be at least sporadic radio-emitters, from 1900 K (L3.5) down to 900 K (T6.5). It also demonstrates that the utility of radio detection as a unique tool to study the magnetic fields of substellar objects extends to the coolest dwarfs, and, plausibly to hot, massive exoplanets. We have also identified a single, 3.6{sigma} flare from the L1 dwarf, 2MASS J1439284+192915. This detection is tentative and requires confirmation by additional monitoring observations.

  16. Observational Evidence of Changing Photospheric Vector Magnetic Fields Associated with Solar Flares

    E-Print Network [OSTI]

    of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012, China 3. Key Laboratory of Solar ActivityObservational Evidence of Changing Photospheric Vector Magnetic Fields Associated with Solar Flares University, Beijing 100875, China sjt@bao.ac.cn Received ; accepted Not to appear in Nonlearned J., 45. #12

  17. CHARACTERISTIC SIZE OF FLARE KERNELS IN THE VISIBLE AND NEAR-INFRARED CONTINUA

    SciTech Connect (OSTI)

    Xu, Yan; Jing, Ju; Wang, Haimin [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States); Cao, Wenda, E-mail: yx2@njit.edu [Big Bear Solar Observatory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States)

    2012-05-01T23:59:59.000Z

    In this Letter, we present a new approach to estimate the formation height of visible and near-infrared emission of an X10 flare. The sizes of flare emission cores in three wavelengths are accurately measured during the peak of the flare. The source size is the largest in the G band at 4308 A and shrinks toward longer wavelengths, namely the green continuum at 5200 A and NIR at 15600 A, where the emission is believed to originate from the deeper atmosphere. This size-wavelength variation is likely explained by the direct heating model as electrons need to move along converging field lines from the corona to the photosphere. Therefore, one can observe the smallest source, which in our case is 0.''65 {+-} 0.''02 in the bottom layer (represented by NIR), and observe relatively larger kernels in upper layers of 1.''03 {+-} 0.''14 and 1.''96 {+-} 0.''27, using the green continuum and G band, respectively. We then compare the source sizes with a simple magnetic geometry to derive the formation height of the white-light sources and magnetic pressure in different layers inside the flare loop.

  18. A STATISTICAL STUDY OF THE SPECTRAL HARDENING OF CONTINUUM EMISSION IN SOLAR FLARES

    SciTech Connect (OSTI)

    Kong, X.; Chen, Y. [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China); Li, G., E-mail: xl_kong@hotmail.com, E-mail: gang.li@uah.edu [Department of Physics and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2013-09-10T23:59:59.000Z

    The observed hard X-ray and {gamma}-ray continuum in solar flares is interpreted as Bremsstrahlung emission of accelerated non-thermal electrons. It has been noted for a long time that in many flares the energy spectra show hardening at energies around or above 300 keV. In this paper, we first conduct a survey of spectral hardening events that were previously studied in the literature. We then perform a systematic examination of 185 flares from the Solar Maximum Mission. We identify 23 electron-dominated events whose energy spectra show clear double power laws. A statistical study of these events shows that the spectral index below the break ({gamma}{sub 1}) anti-correlates with the break energy ({epsilon}{sub b}). Furthermore, {gamma}{sub 1} also anti-correlates with Fr, the fraction of photons above the break compared to the total photons. A hardening spectrum, as well as the correlations between ({gamma}{sub 1}, {epsilon}{sub b}) and ({gamma}{sub 1}, Fr), provide stringent constraints on the underlying electron acceleration mechanism. Our results support a recent proposal that electrons are being accelerated diffusively at a flare termination shock with a width of the order of an ion inertial length scale.

  19. Toward magnetic field dissipation during the 23 July 2002 solar flare measured with Solar

    E-Print Network [OSTI]

    Zharkova, Valentina V.

    and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic] It is widely accepted that the source of primary energy release in solar flares is associated with magnetic

  20. NO FLARES FROM GAMMA-RAY BURST AFTERGLOW BLAST WAVES ENCOUNTERING SUDDEN CIRCUMBURST DENSITY CHANGE

    SciTech Connect (OSTI)

    Gat, Ilana; Van Eerten, Hendrik; MacFadyen, Andrew [Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)

    2013-08-10T23:59:59.000Z

    Afterglows of gamma-ray bursts are observed to produce light curves with the flux following power-law evolution in time. However, recent observations reveal bright flares at times on the order of minutes to days. One proposed explanation for these flares is the interaction of a relativistic blast wave with a circumburst density transition. In this paper, we model this type of interaction computationally in one and two dimensions, using a relativistic hydrodynamics code with adaptive mesh refinement called RAM, and analytically in one dimension. We simulate a blast wave traveling in a stellar wind environment that encounters a sudden change in density, followed by a homogeneous medium, and compute the observed radiation using a synchrotron model. We show that flares are not observable for an encounter with a sudden density increase, such as a wind termination shock, nor for an encounter with a sudden density decrease. Furthermore, by extending our analysis to two dimensions, we are able to resolve the spreading, collimation, and edge effects of the blast wave as it encounters the change in circumburst medium. In all cases considered in this paper, we find that a flare will not be observed for any of the density changes studied.

  1. DIFFERENT PATTERNS OF CHROMOSPHERIC EVAPORATION IN A FLARING REGION OBSERVED WITH HINODE/EIS

    SciTech Connect (OSTI)

    Li, Y.; Ding, M. D., E-mail: dmd@nju.edu.cn [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

    2011-02-01T23:59:59.000Z

    We investigate the chromospheric evaporation in the flare of 2007 January 16 using line profiles observed by the Exterme-UV Imaging Spectrometer on board Hinode. Three points at flare ribbons of different magnetic polarities are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The spectral lines at the first point are mostly blueshifted, with the hotter lines showing a dominant blueshifted component over the stationary one. At the second point, however, only weak upflows are detected; instead, notable downflows appear at high temperatures (up to 2.5-5.0 MK). The third point is similar to the second one only in that it shows evidence of multi-component downflows. While the evaporated plasma falling back down as warm rain is a possible cause of the redshifts at the second and third points, the different patterns of chromospheric evaporation at the three points imply the existence of different heating mechanisms in the flaring active region.

  2. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect (OSTI)

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M. [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 Zagreb (Croatia)

    2012-08-10T23:59:59.000Z

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  3. A COMPREHENSIVE STUDY OF GAMMA-RAY BURST OPTICAL EMISSION. I. FLARES AND EARLY SHALLOW-DECAY COMPONENT

    SciTech Connect (OSTI)

    Li Liang; Liang Enwei; Tang Qingwen; Chen Jiemin; Xi Shaoqiang; Zhang Bing; Lu Ruijing; Lue Lianzhong [Department of Physics and GXU-NAOC, Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Lue Houjun; Gao He [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States); Zhang Jin; Wei Jianyan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Yi Shuangxi, E-mail: lew@gxu.edu.cn, E-mail: zhang@physics.unlv.edu [College of Astronomy and Space Sciences, Nanning University, Nanjing 210093 (China)

    2012-10-10T23:59:59.000Z

    Well-sampled optical light curves of 146 gamma-ray bursts (GRBs) are compiled from the literature. By empirical fitting, we identify eight possible emission components and summarize the results in a 'synthetic' light curve. Both optical flare and early shallow-decay components are likely related to long-term central engine activities. We focus on their statistical properties in this paper. Twenty-four optical flares are obtained from 19 GRBs. The isotropic R-band energy is smaller than 1% of E{sub {gamma},iso}. The relation between the isotropic luminosities of the flares and gamma rays follows L{sup F}{sub R,iso}{proportional_to}L {sup 1.11{+-}0.27}{sub {gamma},iso}. Later flares tend to be wider and dimmer, i.e., w{sup F} {approx} t{sup F}{sub p}/2 and L{sup F}{sub R,iso}{proportional_to}[t{sup F}{sub p}/(1 + z)]{sup -1.15{+-}0.15}. The detection probability of the optical flares is much smaller than that of X-ray flares. An optical shallow-decay segment is observed in 39 GRBs. The relation between the break time and break luminosity is a power law, with an index of -0.78 {+-} 0.08, similar to that derived from X-ray flares. The X-ray and optical breaks are usually chromatic, but a tentative correlation is found. We suggest that similar to the prompt optical emission that tracks {gamma}-rays, the optical flares are also related to the erratic behavior of the central engine. The shallow-decay component is likely related to a long-lasting spinning-down central engine or piling up of flare materials onto the blast wave. Mixing of different emission components may be the reason for the diverse chromatic afterglow behaviors.

  4. Energy loss of fast quarks in nuclei

    SciTech Connect (OSTI)

    Garvey, G. T. (Gerald T.); Johnson, Mikkel B.; Leitch, M. J.; McGaughey, P. L. (Patrick L.); Peng, J. C. (Jen-Chieh); Kopeliovich, B. Z.; Potashnikova, I. K.; Moss, J. M. (Joel Marshall)

    2001-01-01T23:59:59.000Z

    We report an analysis of the nuclear dependence of the yield of Drell-Yan (DY) dimuons from the 800 GeV/c proton bombardment of {sup 2}H, C, Ca, Fe, and W targets. A light-cone formulation of the DY process is employed in the rest frame of the nucleus. In this frame, for x{sub 2} <loss and shadowing, in a consistent formulation. Shadowing, involving no free parameters, is calculated within the light-cone dipole formalism. Initial-state energy loss, the only unknown in the problem, is determined from afit to the nuclear-dependence ratio versus x{sub 1}. With the assumption of constant energy loss per unit path length, we find -dE/dz = 2.32 {+-} 0.52 {+-} 0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in nuclear environment.

  5. High Energy Neutrino Flashes from Far-Ultraviolet and X-ray Flares in Gamma-Ray Bursts

    E-Print Network [OSTI]

    Kohta Murase; Shigehiro Nagataki

    2006-08-07T23:59:59.000Z

    The recent observations of bright optical and x-ray flares by the Swift satellite suggest these are produced by the late activities of the central engine. We study the neutrino emission from far-ultraviolet and x-ray flares under the late internal shock model. We show that the efficiency of pion production in the highest energy is comparable to or higher than the unity, and the contribution from such neutrino flashes to a diffuse very high energy neutrino background can be larger than that of prompt bursts if the total baryonic energy input into flares is comparable to the radiated energy of prompt bursts. These signals may be detected by IceCube and are very important because they have possibilities to probe the nature of flares (the baryon loading, the photon field, the magnetic field and so on).

  6. Physics of ion acceleration in the solar flare on 2005 September 7 determines c-ray and neutron production

    E-Print Network [OSTI]

    California at Berkeley, University of

    de San Andre´s, La Paz, Bolivia m Department of Physics, Tokyo Institute of Technology, Meguro. Angular and energy-dependent neutron emission from solar flare magnetic loops, Astrophys. J. Sup- pl. Ser

  7. GRIEF AND LOSS COUNSELLING AND

    E-Print Network [OSTI]

    Viglas, Anastasios

    LEARN TO UNDERSTAND GRIEF AND LOSS COUNSELLING AND PSYCHOLOGICAL SERVICES (CAPS) #12;The death be tired with no energy or feel sick in the stomach and have headaches. People experiencing grief after

  8. Turbine tip clearance loss mechanisms

    E-Print Network [OSTI]

    Mazur, Steven (Steven Andrew)

    2013-01-01T23:59:59.000Z

    Three-dimensional numerical simulations (RANS and URANS) were used to assess the impact of two specific design features, and of aspects of the actual turbine environment, on turbine blade tip loss. The calculations were ...

  9. Structure and Design a Finance Program with Loan Loss Reserve Funds

    Broader source: Energy.gov [DOE]

    The process for structuring and designing a finance program with a loan loss reserve (LLR) fund typically includes research and preparing a finance program design document.

  10. Photosphere emission in the X-Ray Flares of Swift Gamma-Ray Bursts and Implications for the Fireball Properties

    E-Print Network [OSTI]

    Peng, Fang-Kun; Wang, Xiang-Yu; Hou, Shu-Jin; Xi, Shao-Qiang; Lu, Rui-Jing; Zhang, Jin; Zhang, Bing

    2014-01-01T23:59:59.000Z

    X-ray flares of gamma-ray bursts (GRBs) are usually observed in the soft X-ray range and the spectral coverage is limited. In this paper, we present an analysis of 32 GRB X-ray flares that are simultaneously observed by both BAT and XRT on board the Swift mission, so a joint spectral analysis with a wider spectral coverage is possible. Our results show that the joint spectra of 19 flares are fitted with the absorbed single power-law or the Band function models. More interestingly, the joint spectra of the other 13 X-ray flares are fitted with the absorbed single power-law model plus a black body (BB) component. Phenomenally, the observed spectra of these 13 flares are analogous to several GRBs with a thermal component, but only with a much lower temperature of $kT=1\\sim 3$ keV. Assuming that the thermal emission is the photosphere emission of the GRB fireball, we derive the fireball properties of the 13 flares that have redshift measurements, such as the bulk Lorentz factor $\\Gamma_{\\rm ph}$ of the outflow. T...

  11. Power Laws in Solar Flares: Self-Organized Criticality or Turbulence?

    E-Print Network [OSTI]

    Guido Boffetta; Vincenzo Carbone; Paolo Giuliani; Pierluigi Veltri; Angelo Vulpiani

    1999-04-23T23:59:59.000Z

    We study the time evolution of Solar Flares activity by looking at the statistics of quiescent times $\\tau_{L}$ between successive bursts. The analysis of 20 years of data reveals a power law distribution with exponent $\\alpha \\simeq 2.4$ which is an indication of complex dynamics with long correlation times. The observed scaling behavior is in contradiction with the Self-Organized Criticality models of Solar Flares which predict Poisson-like statistics. Chaotic models, including the destabilization of the laminar phases and subsequent restabilization due to nonlinear dynamics, are able to reproduce the power law for the quiescent times. In the case of the more realistic Shell Model of MHD turbulence we are able to reproduce all the observed distributions.

  12. Hadronic Production of TeV Gamma Ray Flares from Blazars

    E-Print Network [OSTI]

    Arnon Dar; Ari Laor

    1997-01-13T23:59:59.000Z

    We propose that TeV $\\gamma$-ray emission from blazars is produced by collisions near the line of sight of high energy jet protons with gas targets (``clouds'') from the broad emission-line region (BLR). Intense TeV $\\gamma$-ray flares (GRFs) are produced when BLR clouds cross the line of sight close to the black hole. The model reproduces the observed properties of the recently reported very short and intense TeV GRFs from the blazar Markarian 421. Hadronic production of TeV GRF from blazars implies that it is accompanied by a simultaneous emission of high energy neutrinos, and of electrons and positrons with similar intensities, light curves and energy spectra. Cooling of these electrons and positrons by emission of synchrotron radiation and inverse Compton scattering produces delayed optical, X-ray and $\\gamma$-ray flares.

  13. Numerical Study of a Propagating Non-Thermal Microwave Feature in a Solar Flare Loop

    E-Print Network [OSTI]

    T. Minoshima; T. Yokoyama

    2008-06-24T23:59:59.000Z

    We analytically and numerically study the motion of electrons along a magnetic loop, to compare with the observation of the propagating feature of the non-thermal microwave source in the 1999 August 28 solar flare reported by Yokoyama et al. (2002). We model the electron motion with the Fokker-Planck equation and calculate the spatial distribution of the gyrosynchrotron radiation. We find that the microwave propagating feature does not correspond to the motion of electrons with a specific initial pitch angle. This apparent propagating feature is a consequence of the motion of an ensemble of electrons with different initial pitch angles, which have different time and position to produce strong radiation in the loop. We conclude that the non-thermal electrons in the 1999 August 28 flare were isotropically accelerated and then are injected into the loop.

  14. Strongly Blueshifted Phenomena Observed with {\\it Hinode}/EIS in the 2006 December 13 Solar Flare

    E-Print Network [OSTI]

    Ayumi Asai; Hirohisa Hara; Tetsuya Watanabe; Shinsuke Imada; Taro Sakao; Noriyuki Narukage; J. L. Culhane; G. A. Doschek

    2008-05-29T23:59:59.000Z

    We present a detailed examination of strongly blueshifted emission lines observed with the EUV Imaging Spectrometer on board the {\\it Hinode} satellite. We found two kinds of blueshifted phenomenon associated with the X3.4 flare that occurred on 2006 December 13. One was related to a plasmoid ejection seen in soft X-rays. It was very bright in all the lines used for the observations. The other was associated with the faint arc-shaped ejection seen in soft X-rays. The soft X-ray ejection is thought to be an MHD fast-mode shock wave. This is therefore the first spectroscopic observation of an MHD fast-mode shock wave associated with a flare.

  15. An Accretion-Induced X-ray Flare in Sgr A*

    E-Print Network [OSTI]

    Siming Liu; Fulvio Melia

    2002-01-21T23:59:59.000Z

    The recent detection of a three-hour X-ray flare from Sgr A* by Chandra provides very strong evidence for a compact emitting region near this supermassive black hole at the Galactic center. Sgr A*'s mm/sub-mm spectrum and polarimetric properties, and its quiescent-state X-ray flux density, are consistent with a model in which low angular momentum gas captured at large radii circularizes to form a hot, magnetized Keplerian flow within tens of Schwarzschild radii of the black hole's event horizon. In Sgr A*'s quiescent state, the X-ray emission appears to be produced by self-Comptonization (SSC) of the mm/sub-mm synchrotron photons emitted in this region. In this paper, we show that the prominent X-ray flare seen in Sgr A* may be due to a sudden enhancement of accretion through the circularized flow. Depending on whether the associated response of the anomalous viscosity is to increase or decrease in tandem with this additional injection of mass, the X-ray photons during the outburst may be produced either via thermal bremsstrahlung (if the viscosity decreases), or via SSC (if the viscosity increases). However, the latter predicts a softer X-ray spectrum than was seen by Chandra, so it appears that a bremsstrahlung origin for the X-ray outburst is favored. A strong correlation is expected between the mm/sub-mm and X-ray fluxes when the flare X-rays are produced by SSC, while the correlated variability is strongest between the sub-mm/far-IR and X-rays when bremsstrahlung emission is dominant during the flare. In addition, we shows that future coordinated multi-wavelength observations planned for the 2002 and 2003 cycles may be able to distinguish between the accretion and jet scenarios.

  16. THE WHITE LIGHT LIMB FLARE OF 16 AUGUST 1989 AND ITS CHROMOSPHERIC COUNTERPART

    E-Print Network [OSTI]

    Li, Hui

    THE WHITE LIGHT LIMB FLARE OF 16 AUGUST 1989 AND ITS CHROMOSPHERIC COUNTERPART Jianqi You 1 comparing the white-light (#21;5600 #6; 800 #23; A) and the slit-jaw H#11; images (0.5 #23; A passband) of the 2N/X20 white-light are of 16 August 1989, we found that the H#11; counterpart identi#12;cation

  17. Impulsive phase flare energy transport by large-scale Alfven waves and the electron acceleration problem

    E-Print Network [OSTI]

    Fletcher, L

    2007-01-01T23:59:59.000Z

    The impulsive phase of a solar flare marks the epoch of rapid conversion of energy stored in the pre-flare coronal magnetic field. Hard X-ray observations imply that a substantial fraction of flare energy released during the impulsive phase is converted to the kinetic energy of mildly relativistic electrons (10-100 keV). The liberation of the magnetic free energy can occur as the coronal magnetic field reconfigures and relaxes following reconnection. We investigate a scenario in which products of the reconfiguration - large-scale Alfven wave pulses - transport the energy and magnetic-field changes rapidly through the corona to the lower atmosphere. This offers two possibilities for electron acceleration. Firstly, in a coronal plasma with beta < m_e/m_p, the waves propagate as inertial Alfven waves. In the presence of strong spatial gradients, these generate field-aligned electric fields that can accelerate electrons to energies on the order of 10 keV and above, including by repeated interactions between el...

  18. Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare

    E-Print Network [OSTI]

    Tian, Hui; Reeves, Katharine K; Raymond, John C; Guo, Fan; Liu, Wei; Chen, Bin; Murphy, Nicholas A

    2014-01-01T23:59:59.000Z

    Magnetic reconnection is believed to be the dominant energy release mechanism in solar flares. The standard flare model predicts both downward and upward outflow plasmas with speeds close to the coronal Alfv\\'{e}n speed. Yet, spectroscopic observations of such outflows, especially the downflows, are extremely rare. With observations of the newly launched Interface Region Imaging Spectrograph (IRIS), we report the detection of greatly redshifted ($\\sim$125 km s$^{-1}$ along line of sight) Fe {\\sc{xxi}} 1354.08\\AA{} emission line with a $\\sim$100 km s$^{-1}$ nonthermal width at the reconnection site of a flare. The redshifted Fe {\\sc{xxi}} feature coincides spatially with the loop-top X-Ray source observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We interpret this large redshift as the signature of downward-moving reconnection outflow/hot retracting loops. Imaging observations from both IRIS and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) also...

  19. X-ray flare in XRF 050406: evidence for prolonged engine activity

    E-Print Network [OSTI]

    Romano, P; Banat, P L; Burrows, D N; Campana, S; Chincarini, G; Covino, S; Malesani, D; Tagliaferri, G; Kobayashi, S; Zhang, B; Falcone, A D; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Cusumano, G; Giommi, P; Goad, M R; Godet, O; Grupe, D; Hill, J E; Kennea, J A; La Parola, V; Mangano, V; Mészáros, P; Morris, D C; Nousek, J A; O'Brien, P T; Osborne, J P; Parsons, A; Perri, M; Pagani, C; Page, K L; Wells, A A; Gehrels, N

    2006-01-01T23:59:59.000Z

    We present observations of XRF 050406, the first burst detected by Swift showing a flare in its X-ray light curve. During this flare, which peaks at t_peak ~210s after the BAT trigger, a flux variation of (delta F)/F~6 in a very short time (delta t)/t_peak<<1 was observed. Its measured fluence in the 0.2-10 keV band was ~1.4x10^-8 erg cm^-2, which corresponds to 1-15% of the prompt fluence. We present indications of spectral variations during the flare. We argue that the producing mechanism is late internal shocks, which implies that the central engine is still active at 210s, though with a reduced power with respect to the prompt emission. The X-ray light curve flattens to a very shallow slope with decay index of ~0.5 after ~4400s, which also supports continued central engine activity at late times. This burst is classified as an X-ray flash, with a relatively low fluence (~10^-7 erg cm^-2 in the 15-350 keV band, E_iso~10^51 erg), a soft spectrum (photon index 2.65), no significant flux above ~50 keV a...

  20. The accretion environment in Vela X-1 during a flaring period using XMM-Newton

    E-Print Network [OSTI]

    Martínez-Núñez, Silvia; Kühnel, Matthias; Kretschmar, Peter; Stuhlinger, Martin; Rodes-Roca, José Joaquín; Fürst, Feliz; Kreykenbohm, Ingo; Martin-Carrillo, Antonio; Pollock, Andy M T; Wilms, Joern

    2014-01-01T23:59:59.000Z

    We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of $3.92^{+0.42}_{-0.09} \\times 10^{37}$ erg s$^{-1}$ cm$^{-2}$ allows estimates of the physical parameters of the accreted structure with a mass of $\\sim$ $10^{21}$ g. We have been able to model several contributions to the observed spectrum with a phenomenological model formed by three absorbed power laws plus three emission lines. After analysing the variations with orbital phase of the column density of each component, as well as those in the Fe and Ni fluorescence lines, we provide a physical interpretation for each spectral component. Meanwhile, the first two components are two aspects of the principal accretion component from the surface of the neutron star, and the thi...

  1. Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare

    E-Print Network [OSTI]

    T. Minoshima; T. Yokoyama; N. Mitani

    2007-10-02T23:59:59.000Z

    We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of microwave peaks relative to HXR peaks, loop-top microwave and footpoint HXR sources, and a harder electron energy distribution inferred from the microwave spectrum than from the HXR spectrum. In addition, we found that the time profile of the spectral index of the higher-energy ($\\gsim 100$ keV) HXRs is similar to that of the microwaves, and is delayed from that of the lower-energy ($\\lsim 100$ keV) HXRs. We interpret these observations in terms of an electron transport model called {\\TPP}. We numerically solved the spatially-homogeneous {\\FP} equation to determine electron evolution in energy and pitch-angle space. By comparing the behaviors of the HXR and microwave emissions predicted by the model with the observations, we discuss the pitch-angle distribution of the electrons injected into the flare site. We found that the observed spectral variations can qualitatively be explained if the injected electrons have a pitch-angle distribution concentrated perpendicular to the magnetic field lines rather than isotropic distribution.

  2. RESIK Solar X-ray flare element abundances on a non-isothermal assumption

    E-Print Network [OSTI]

    Sylwester, B; Sylwester, J; Kepa, A

    2015-01-01T23:59:59.000Z

    Solar X-ray spectra from the RESIK crystal spectrometer on the {\\em CORONAS-F} spacecraft (spectral range $3.3-6.1$~\\AA) are analyzed for thirty-three flares using a method to derive abundances of Si, S, Ar, and K, emission lines of which feature prominently in the spectra. For each spectrum, the method first optimizes element abundances then derives the differential emission measure as a function of temperature based on a procedure given by Sylwester et al. and Withbroe. This contrasts with our previous analyses of RESIK spectra in which an isothermal assumption was used. The revised abundances (on a logarithmic scale with $A({\\rm H}) = 12$) averaged for all the flares in the analysis are $A({\\rm Si}) = 7.53 \\pm 0.08$ (previously $7.89 \\pm 0.13$), $A({\\rm S}) = 6.91 \\pm 0.07$ ($7.16 \\pm 0.17$), $A({\\rm Ar}) = 6.47 \\pm 0.08$ ($6.45 \\pm 0.07$), and $A({\\rm K}) = 5.73 \\pm 0.19$ ($5.86 \\pm 0.20$), with little evidence for time variations of abundances within the evolution of each flare. Our previous estimates of...

  3. MODELING OF GYROSYNCHROTRON RADIO EMISSION PULSATIONS PRODUCED BY MAGNETOHYDRODYNAMIC LOOP OSCILLATIONS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2012-04-01T23:59:59.000Z

    A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

  4. Magnetohydrodynamic Simulation of the X2.2 Solar Flare on 2011 February 15: II. A Dynamics Connecting the Solar Flare and the Coronal Mass Ejection

    E-Print Network [OSTI]

    Inoue, S; Magara, T; Choe, G S; Park, Y D

    2015-01-01T23:59:59.000Z

    We clarify a relationship of the dynamics of a solar flare and a growing Coronal Mass Ejection (CME) by investigating the dynamics of magnetic fields during the X2.2-class flare taking place in the solar active region 11158 on 2011 February 15, based on simulation results obtained from Inoue et al. 2014. We found that the strongly twisted lines formed through the tether-cutting reconnection in the twisted lines of a nonlinear force-free field (NLFFF) can break the force balance within the magnetic field, resulting in their launch from the solar surface. We further discover that a large-scale flux tube is formed during the eruption as a result of the tether-cutting reconnection between the eruptive strongly twisted lines and these ambient weakly twisted lines. Then the newly formed large flux tube exceeds the critical height of the torus instability. The tether-cutting reconnection thus plays an important role in the triggering a CME. Furthermore, we found that the tangential fields at the solar surface illust...

  5. Cancer Vulnerabilities Unveiled by Genomic Loss

    E-Print Network [OSTI]

    Nijhawan, Deepak

    Due to genome instability, most cancers exhibit loss of regions containing tumor suppressor genes and collateral loss of other genes. To identify cancer-specific vulnerabilities that are the result of copy number losses, ...

  6. Efficiency loss in resource allocation games

    E-Print Network [OSTI]

    Xu, Yunjian

    2012-01-01T23:59:59.000Z

    The overarching goals of this thesis are to quantify the efficiency loss due to market participant strategic behavior, and to design proper pricing mechanisms that reduce the efficiency loss. The concept of efficiency loss ...

  7. HELIOPHYSICS II. ENERGY CONVERSION PROCESSES

    E-Print Network [OSTI]

    Hudson, Hugh

    of a solar flare 11 2.3.1 Flare luminosity and mechanical energy 11 2.3.2 The impulsive phase (hard X with the term "solar flare" dominate our thinking about energy conversion from magnetic storage to other forms approaches to the problems involved in phys- ically characterizing the solar atmosphere; see also the lecture

  8. Adjustable Speed- A Tool for Saving Energy Losses in Pumps, Fans, Fans, Blowers and Compressors

    E-Print Network [OSTI]

    Hickok, H. N.

    Petroleum and chemical plants of today are effectively cutting energy losses in their plants thermally, electrically, and mechanically in their process equipment. In rotating process equipment such as pumps, fans, compressors, and blowers, much...

  9. Solar Flare Prediction Using SDO/HMI Vector Magnetic Field Data with a Machine-Learning Algorithm

    E-Print Network [OSTI]

    Bobra, Monica G

    2014-01-01T23:59:59.000Z

    We attempt to forecast M-and X-class solar flares using a machine-learning algorithm, called Support Vector Machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space. Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time a large dataset of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2,071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters. We then train and test the machine-learning algorithm and we estimate its performances using forecast verification metrics with an emphasis on the True Skill Statistic (TSS). We obtain relatively h...

  10. GALEX Observations of an Energetic Ultraviolet Flare on the dM4e Star GJ 3685A

    E-Print Network [OSTI]

    Richard D. Robinson; Jonathan M. Wheatley; Barry Y. Welsh; Karl Forster; Patrick Morrissey; Mark Seibert; R. Michael Rich; Samir Salim; Tom A. Barlow; Luciana Bianchi; Yong-Ik Byun; Jose Donas; Peter G. Friedman; Timothy M. Heckman; Patrick N. Jelinsky; Young-Wook Lee; Barry F. Madore; Roger F. Malina; D. Christopher Martin; Bruno Milliard; Susan G. Neff; David Schiminovich; Oswald H. W. Siegmund; Todd Small; Alex S. Szalay; Ted K. Wyder

    2005-07-18T23:59:59.000Z

    The Galaxy Evolution Explorer (GALEX) satellite has obtained high time resolution ultraviolet photometry during a large flare on the M4 dwarf star GJ 3685A. Simultaneous NUV (1750 - 2800A) and FUV (1350 - 1750A) time-tagged photometry with time resolution better than 0.1 s shows that the overall brightness in the FUV band increased by a factor of 1000 in 200 s. Under the assumption that the NUV emission is mostly due to a stellar continuum, and that the FUV flux is shared equally between emission lines and continuum, then there is evidence for two distinct flare components for this event. The first flare type is characterized by an exponential increase in flux with little or no increase in temperature. The other involves rapid increases in both temperature and flux. While the decay time for the first flare component may be several hours, the second flare event decayed over less than 1 minute, suggesting that there was little or no confinement of the heated plasma.

  11. RELATIVISTIC SHOCK BREAKOUTS-A VARIETY OF GAMMA-RAY FLARES: FROM LOW-LUMINOSITY GAMMA-RAY BURSTS TO TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Sari, Re'em [Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)

    2012-03-10T23:59:59.000Z

    The light from a shock breakout of stellar explosions, which carries a wealth of information, strongly depends on the shock velocity at the time of the breakout. The emission from Newtonian breakouts, typical in regular core-collapse supernovae (SNe), has been explored extensively. However, a large variety of explosions result in mildly or ultrarelativistic breakouts, where the observed signature is unknown. Here we calculate the luminosity and spectrum produced by relativistic breakouts. In order to do so, we improve the analytic description of relativistic radiation-mediated shocks and follow the system from the breakout itself, through the planar phase and into the spherical phase. We limit our calculation to cases where the post-breakout acceleration of the gas ends during the planar phase (i.e., the final gas Lorentz factor {approx}< 30). We find that spherical relativistic breakouts produce a flash of gamma rays with energy, E{sub bo}, temperature, T{sub bo}, and duration, t{sup obs} b{sub o}, that provide the breakout radius ( Almost-Equal-To 5 R{sub Sun }(t{sup obs}{sub bo}/10 s)(T{sub bo}/50 keV){sup 2}) and the Lorentz factor ( Almost-Equal-To T{sub bo}/50 keV). They also always satisfy a relativistic breakout relation (t{sup obs}{sub bo}/20 s) {approx} (E{sub bo}/10{sup 46} erg){sup 1/2}(T{sub bo}/50 keV){sup -2.68}. The breakout flare is typically followed, on longer timescales, by X-rays that carry a comparable energy. We apply our model to a variety of explosions, including Type Ia and .Ia SNe, accretion-induced collapse, energetic SNe, and gamma-ray bursts (GRBs). We find that all these events produce detectable gamma-ray signals, some of which may have already been seen. Some particular examples are: (1) relativistic shock breakouts provide a natural explanation to the energy, temperature, and timescales of low-luminosity GRBs. Indeed, all observed low-luminosity GRBs satisfy the relativistic breakout relation. (2) Nearby broad-line Type Ib/c (like SN 2002ap) may produce a detectable {gamma}-ray signal. (3) Galactic Type Ia SNe may produce detectable {gamma}-ray flares. We conclude that relativistic shock breakouts provide a generic process for the production of gamma-ray flares.

  12. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 99, NO. A12, PAGES 23,289-23,296, DECEMBER 1, 1994 Solar flare effectsat Ebre: Unidimensionalphysical,integrated

    E-Print Network [OSTI]

    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 99, NO. A12, PAGES 23,289-23,296, DECEMBER 1, 1994 Solar.M. Torta,· andM. Menvielle3 Abstract. A great increaseof the ionizing radiationduring solar flares,electrondensitiesandelectriccurrents in the ionosphere,followedsimultaneouslyby disturbancesof the magneticelementsat groundlevel (solar flare effects

  13. ANALYSIS AND MODELING OF TWO FLARE LOOPS OBSERVED BY AIA AND EIS

    SciTech Connect (OSTI)

    Li, Y.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Qiu, J. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2012-10-10T23:59:59.000Z

    We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in extreme ultraviolet (EUV) images. The UV 1600 A emission at the feet of these loops exhibits a rapid rise, followed by enhanced emission in different EUV channels observed by the Atmospheric Imaging Assembly (AIA) and the EUV Imaging Spectrometer (EIS). Such behavior is indicative of impulsive energy deposit and the subsequent response in overlying coronal loops that evolve through different temperatures. Using the method we recently developed, we infer empirical heating functions from the rapid rise of the UV light curves for the two loop systems, respectively, treating them as two big loops with cross-sectional area of 5'' by 5'', and compute the plasma evolution in the loops using the EBTEL model. We compute the synthetic EUV light curves, which, with the limitation of the model, reasonably agree with observed light curves obtained in multiple AIA channels and EIS lines: they show the same evolution trend and their magnitudes are comparable by within a factor of two. Furthermore, we also compare the computed mean enthalpy flow velocity with the Doppler shift measurements by EIS during the decay phase of the two loops. Our results suggest that the two different loops with different heating functions as inferred from their footpoint UV emission, combined with their different lengths as measured from imaging observations, give rise to different coronal plasma evolution patterns captured both in the model and in observations.

  14. PROBING DYNAMICS OF ELECTRON ACCELERATION WITH RADIO AND X-RAY SPECTROSCOPY, IMAGING, AND TIMING IN THE 2002 APRIL 11 SOLAR FLARE

    SciTech Connect (OSTI)

    Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Kontar, Eduard P. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-05-10T23:59:59.000Z

    Based on detailed analysis of radio and X-ray observations of a flare on 2002 April 11 augmented by realistic three-dimensional modeling, we have identified a radio emission component produced directly at the flare acceleration region. This acceleration region radio component has distinctly different (1) spectrum, (2) light curves, (3) spatial location, and, thus, (4) physical parameters from those of the separately identified trapped or precipitating electron components. To derive evolution of physical parameters of the radio sources we apply forward fitting of the radio spectrum time sequence with the gyrosynchrotron source function with five to six free parameters. At the stage when the contribution from the acceleration region dominates the radio spectrum, the X-ray- and radio-derived electron energy spectral indices agree well with each other. During this time the maximum energy of the accelerated electron spectrum displays a monotonic increase with time from {approx}300 keV to {approx}2 MeV over roughly one minute duration indicative of an acceleration process in the form of growth of the power-law tail; the fast electron residence time in the acceleration region is about 2-4 s, which is much longer than the time of flight and so requires a strong diffusion mode there to inhibit free-streaming propagation. The acceleration region has a relatively strong magnetic field, B {approx} 120 G, and a low thermal density, n{sub e} {approx}< 2 Multiplication-Sign 10{sup 9} cm{sup -3}. These acceleration region properties are consistent with a stochastic acceleration mechanism.

  15. Detecting Flaring Structures in Sagittarius A* with (Sub)Millimeter VLBI

    E-Print Network [OSTI]

    Vincent L. Fish; Sheperd S. Doeleman; Avery E. Broderick; Abraham Loeb; Alan E. E. Rogers

    2008-07-15T23:59:59.000Z

    Multiwavelength monitoring observations of Sagittarius A* exhibit variability on timescales of minutes to hours, indicating emission regions localized near the event horizon. (Sub)Millimeter-wavelength VLBI is uniquely suited to probe the environment of the assumed black hole on these scales. We consider a range of orbiting hot-spot and accretion-disk models and find that periodicity in Sgr A* flares is detectable using closure quantities. Our methods are applicable to any model producing source structure changes near the black hole, including jets and magnetohydrodynamic disk instabilities, and suggest that (sub)millimeter VLBI will play a prominent role in investigating Sgr A* near the event horizon.

  16. Observations of a Correlated Gamma-Ray and Optical Flare for BL Lacertae

    E-Print Network [OSTI]

    S. D. Bloom

    1997-09-25T23:59:59.000Z

    The latest observations of BL Lacertae with the EGRET instrument on CGRO show that the gamma-ray flux was four times higher than the previous detection. Within the 1997 July 15-22 observation there was a dramatic factor of 2.5 increase in the gamma-ray flux, with a sharp peak of about 8 hours, and apparently preceding a brief optical flare by several hours. The gamma-ray photon spectral index was significantly harder than that for the previous detection.

  17. PROPERTIES OF A SOLAR FLARE KERNEL OBSERVED BY HINODE AND SDO

    SciTech Connect (OSTI)

    Young, P. R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)] [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Doschek, G. A.; Warren, H. P. [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)] [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Hara, H. [National Astronomical Observatory of Japan/NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan/NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2013-04-01T23:59:59.000Z

    Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare in active region AR 11158 observed on 2011 February 16 07:44 UT for which the location of the upflow region seen by EUV Imaging Spectrometer (EIS) can be precisely aligned to high spatial resolution images obtained by the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). A string of bright flare kernels is found to be aligned with a ridge of strong magnetic field, and one kernel site is highlighted for which an upflow speed of Almost-Equal-To 400 km s{sup -1} is measured in lines formed at 10-30 MK. The line-of-sight magnetic field strength at this location is Almost-Equal-To 1000 G. Emission over a continuous range of temperatures down to the chromosphere is found, and the kernels have a similar morphology at all temperatures and are spatially coincident with sizes at the resolution limit of the AIA instrument ({approx}<400 km). For temperatures of 0.3-3.0 MK the EIS emission lines show multiple velocity components, with the dominant component becoming more blueshifted with temperature from a redshift of 35 km s{sup -1} at 0.3 MK to a blueshift of 60 km s{sup -1} at 3.0 MK. Emission lines from 1.5-3.0 MK show a weak redshifted component at around 60-70 km s{sup -1} implying multi-directional flows at the kernel site. Significant non-thermal broadening corresponding to velocities of Almost-Equal-To 120 km s{sup -1} is found at 10-30 MK, and the electron density in the kernel, measured at 2 MK, is 3.4 Multiplication-Sign 10{sup 10} cm{sup -3}. Finally, the Fe XXIV {lambda}192.03/{lambda}255.11 ratio suggests that the EIS calibration has changed since launch, with the long wavelength channel less sensitive than the short wavelength channel by around a factor two.

  18. Dimensioning hospital wards using the Erlang loss model Corresponding author

    E-Print Network [OSTI]

    -2006. Finally, we demonstrate the efficiency of merging departments. Keywords: hospital resource allocationDimensioning hospital wards using the Erlang loss model Corresponding author: A.M. de Bruin (MSc of Sciences Department of Mathematics Assistant professor Optimization of Business Processes L. van Zanten

  19. Chromospheric heating by electron and proton bombardment in the solar flare of June 7, 1980. Research note

    SciTech Connect (OSTI)

    Emslie, A.G.

    1982-12-01T23:59:59.000Z

    Using observations of both hard x-rays and gamma-rays in the large solar flare on June 7, 1980, we infer the amount of chromospheric heating due to bombardment both by non-thermal electrons and by protons, respectively. If a thick-target model for the X-ray bremsstrahlung is adopted, then proton heating is shown to be important only in the lower chromosphere; however, if the hard X-rays are substantially thermal in origin, then proton heating may play an important or indeed dominant role in determining the structure of the entire flaring chromosphere.

  20. Quantum cryptographic system with reduced data loss

    DOE Patents [OSTI]

    Lo, H.K.; Chau, H.F.

    1998-03-24T23:59:59.000Z

    A secure method for distributing a random cryptographic key with reduced data loss is disclosed. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically. 23 figs.

  1. Quantum cryptographic system with reduced data loss

    DOE Patents [OSTI]

    Lo, Hoi-Kwong (1309, Low Block, Lei Moon House Ap Lei Chau Estate, Hong Kong, HK); Chau, Hoi Fung (Flat C, 42nd Floor, Tower 1, University Heights 23 Pokfield Road, Pokfulam, Hong Kong, HK)

    1998-01-01T23:59:59.000Z

    A secure method for distributing a random cryptographic key with reduced data loss. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically.

  2. Volatile organic compound losses from sewage sludge-amended soils

    SciTech Connect (OSTI)

    Wilson, S.C.; Jones, K.C.

    1999-08-01T23:59:59.000Z

    Volatile organic compounds (VOCs) applied to soil in sludge have been assumed to disappear quickly and completely. The VOC behavior in sludge-amended soils has been studied previously only in laboratory systems where the sludged soil has been spiked with compounds of interest. Behavior in these systems may not necessarily represent compound behavior in field soils to which contaminated sludge is added. A series of laboratory microcosm experiments were designed therefore to investigate the behavior of toluene, ethyl benzene, o-, m-, and p-xylene applied to soil in contaminated sludge, and factors influencing loss processes. The VOC loss from sludge-amended soil was well described by a simple one step pseudo-first-order model but in certain soils was better described by a two step first-order model. Volatilization was the predominant loss process. Rates of loss depended on sludge application rate, method of sludge application, soil properties, and on compound characteristics. Experiments indicated that spiking sludge-amended soils gave a reasonable indication of VOC loss rates from systems amended with contaminated sludge at least over a period of 23 d. The majority of VOCs applied to soils in sludge volatilizes quickly to the atmosphere over a few to 10s of days with a small fraction lost more slowly. Potential for VOC crop uptake, livestock ingestion, and contamination of ground water is low under routine, managed applications of sewage sludge to agricultural land.

  3. Periodic Modulations in an X-ray Flare from Sagittarius A*

    E-Print Network [OSTI]

    Guillaume Belanger; Regis Terrier; Okkie De Jager; Andrea Goldwurm; Fulvio Melia

    2006-04-23T23:59:59.000Z

    We present the highly significant detection of a quasi-periodic flux modulation with a period of 22.2 min seen in the X-ray data of the Sgr A* flare of 2004 August 31. This flaring event, which lasted a total of about three hours, was detected simultaneously by EPIC on XMM-Newton and the NICMOS near-infrared camera on the HST. Given the inherent difficulty in, and the lack of readily available methods for quantifying the probability of a periodic signal detected over only several cycles in a data set where red noise can be important, we developed a general method for quantifying the likelihood that such a modulation is indeed intrinsic to the source and does not arise from background fluctuations. We here describe this Monte Carlo based method, and discuss the results obtained by its application to a other XMM-Newton data sets. Under the simplest hypothesis that we witnessed a transient event that evolved, peaked and decayed near the marginally stable orbit of the supermassive black hole, this result implies that for a mass of 3.5 x 10^{6} Msun, the central object must have an angular momentum corresponding to a spin parameter of a=0.22.

  4. A Possible Rossby Wave Instability Origin for the Flares in Sagittarius A*

    E-Print Network [OSTI]

    Michel Tagger; Fulvio Melia

    2005-11-17T23:59:59.000Z

    In recent years, near-IR and X-ray flares have been detected from the Galaxy's central radio point source, Sagittarius A* (Sgr A*), believed to be a \\~3.10^6 solar masses supermassive black hole. In some cases, the transient emission appears to be modulated with a (quasi-)periodic oscillation (QPO) of ~ 17-20 minutes. The implied ~ 3 r_S size of the emitter (where r_S = 2GM/c^2 is the Schwarzschild radius) points to an instability - possibly induced by accretion - near the Marginally Stable Orbit (MSO) of a slowly spinning object. But Sgr A* is not accreting via a large, `standard' disk; instead, the low density environment surrounding it apparently feeds the black hole with low angular momentum clumps of plasma that circularize within ~ 10-300 r_S and merge onto a compact, hot disk. In this Letter, we follow the evolution of the disk following such an event, and show that a Rossby wave instability, particularly in its magnetohydrodynamic (MHD) form, grows rapidly and produces a period of enhanced accretion lasting several hours. Both the amplitude of this response, and its duration, match the observed flare characteristics rather well.

  5. PROPAGATION OF ALFVENIC WAVES FROM CORONA TO CHROMOSPHERE AND CONSEQUENCES FOR SOLAR FLARES

    SciTech Connect (OSTI)

    Russell, A. J. B.; Fletcher, L. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom)

    2013-03-10T23:59:59.000Z

    How do magnetohydrodynamic waves travel from the fully ionized corona, into and through the underlying partially ionized chromosphere, and what are the consequences for solar flares? To address these questions, we have developed a two-fluid model (of plasma and neutrals) and used it to perform one-dimensional simulations of Alfven waves in a solar atmosphere with realistic density and temperature structure. Studies of a range of solar features (faculae, plage, penumbra, and umbra) show that energy transmission from corona to chromosphere can exceed 20% of incident energy for wave periods of 1 s or less. Damping of waves in the chromosphere depends strongly on wave frequency: waves with periods 10 s or longer pass through the chromosphere with relatively little damping, however, for periods of 1 s or less, a substantial fraction (37%-100%) of wave energy entering the chromosphere is damped by ion-neutral friction in the mid- and upper chromosphere, with electron resistivity playing some role in the lower chromosphere and in umbras. We therefore conclude that Alfvenic waves with periods of a few seconds or less are capable of heating the chromosphere during solar flares, and speculate that they could also contribute to electron acceleration or exciting sunquakes.

  6. Multifrequency Studies of the Peculiar Quasar 4C +21.35 During the 2010 Flaring Activity

    E-Print Network [OSTI]

    Ackermann, M; Allafort, A; Antolini, E; Barbiellini, G; Bastieri, D; Bellazzini, R; Bissaldi, E; Bonamente, E; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Cecchi, C; Chaves, R C G; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; D'Ammando, F; de Palma, F; Dermer, C D; Silva, E do Couto e; Donato, D; Drell, P S; Favuzzi, C; Finke, J; Focke, W B; Franckowiak, A; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Godfrey, G; Grenier, I A; Guiriec, S; Hayashida, M; Hewitt, J W; Horan, D; Hughes, R E; Iafrate, G; Johnson, A S; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mayer, M; Mazziotta, M N; McEnery, J E; Michelson, P F; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohsugi, T; Orienti, M; Orlando, E; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Razzano, M; Reimer, A; Reimer, O; Sanchez, D A; Schulz, A; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Stawarz, L; Takahashi, H; Takahashi, T; Thayer, J G; Thayer, J B; Thompson, D J; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Werner, M; Winer, B L; Wood, D L; Wood, K S; Aleksic, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; de Almeida, U Barres; Barrio, J A; Gonzalez, J Becerra; Bednarek, W; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Fidalgo, D Carreto; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Mendez, C Delgado; Doert, M; Dominguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Farina, E; Ferenc, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Lopez, R J Garcia; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giavitto, G; Godinovic, N; Munoz, A Gonzalez; Gozzini, S R; Hadasch, D; Herrero, A; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Knoetig, M L; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Lopez, M; Lopez-Coto, R; Lopez-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martinez, M; Mazin, D; Menzel, U; Meucci, M; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nishijima, K; Nilsson, K; Nowak, N; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Partini, S; Persic, M; Prada, F; Moroni, P G Prada; Prandini, E; Preziuso, S; Puljak, I; Reinthal, R; Rhode, W; Ribo, M; Rico, J; Garcia, J Rodriguez; Rugamer, S; Saggion, A; Saito, T; Saito, K; Salvati, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpaa, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Sun, S; Suric, T; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzic, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Toyama, T; Treves, A; Vogler, P; Wagner, R M; Zandanel, F; Zanin, R; Aller, M F; Angelakis, E; Blinov, D A; Djorgovski, S G; Drake, A J; Efimova, N V; Gurwell, M A; Homan, D C; Jordan, B; Kopatskaya, E N; Kovalev, Y Y; Kurtanidze, O M; Lahteenmaki, A; Larionov, V M; Lister, M L; Nieppola, E; Nikolashvili, M G; Ros, E; Savolainen, T; Sigua, L A; Tornikoski, M; .,

    2014-01-01T23:59:59.000Z

    The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) gamma-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE; E > 100 MeV) gamma-rays, poses intriguing questions on the location of the gamma-ray emitting region in this flat spectrum radio quasar (FSRQ). We present multifrequency data of 4C +21.35 collected from centimeter to VHE during 2010 to investigate the properties of this source and discuss a possible emission model. The first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon after a gamma-ray flare detected by Fermi-LAT that peaked on April 29. The same emission mechanism may therefore be responsible for both the HE and VHE emission during the 2010 flaring episodes. Two optical peaks were detected on 2010 April 20 and June 30, close in time but not simultaneous with the two gamma-ray peaks, while no clear connection was observed between the X-ray an gam...

  7. Recovery Act: ArcelorMittal USA Blast Furnace Gas Flare Capture

    SciTech Connect (OSTI)

    Seaman, John

    2013-01-14T23:59:59.000Z

    The U.S. Department of Energy (DOE) awarded a financial assistance grant under the American Recovery and Reinvestment Act of 2009 (Recovery Act) to ArcelorMittal USA, Inc. (ArcelorMittal) for a project to construct and operate a blast furnace gas recovery boiler and supporting infrastructure at ArcelorMittal’s Indiana Harbor Steel Mill in East Chicago, Indiana. Blast furnace gas (BFG) is a by-product of blast furnaces that is generated when iron ore is reduced with coke to create metallic iron. BFG has a very low heating value, about 1/10th the heating value of natural gas. BFG is commonly used as a boiler fuel; however, before installation of the gas recovery boiler, ArcelorMittal flared 22 percent of the blast furnace gas produced at the No. 7 Blast Furnace at Indiana Harbor. The project uses the previously flared BFG to power a new high efficiency boiler which produces 350,000 pounds of steam per hour. The steam produced is used to drive existing turbines to generate electricity and for other requirements at the facility. The goals of the project included job creation and preservation, reduced energy consumption, reduced energy costs, environmental improvement, and sustainability.

  8. Low-energy cutoffs in electron spectra of solar flares: statistical survey

    E-Print Network [OSTI]

    E. P. Kontar; E. Dickson; J. Kasparova

    2008-05-21T23:59:59.000Z

    The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) X-ray data base (February 2002 -- May 2006) has been searched to find solar flares with weak thermal components and flat photon spectra. Using a regularised inversion technique, we determine the mean electron flux distribution from count spectra of a selection of events with flat photon spectra in the 15--20 keV energy range. Such spectral behaviour is expected for photon spectra either affected by photospheric albedo or produced by electron spectra with an absence of electrons in a given energy range, e.g. a low-energy cutoff in the mean electron spectra of non-themal particles. We have found 18 cases which exhibit a statistically significant local minimum (a dip) in the range of 10--20 keV. The positions and spectral indices of events with low-energy cutoff indicate that such features are likely to be the result of photospheric albedo. It is shown that if the isotropic albedo correction was applied, all low-energy cutoffs in the mean electron spectrum were removed and hence the low energy cutoffs in the mean electron spectrum of solar flares above $\\sim$12 keV cannot be viewed as real features in the electron spectrum. If low-energy cutoffs exist in the mean electron spectra, the energy of low energy cutoffs should be less than $\\sim$12 keV.

  9. Heating and Dynamics of Two Flare Loop Systems Observed by AIA and EIS

    E-Print Network [OSTI]

    Li, Y; Ding, M D

    2013-01-01T23:59:59.000Z

    We investigate heating and evolution of flare loops in a C4.7 two-ribbon flare on 2011 February 13. From SDO/AIA imaging observations, we can identify two sets of loops. Hinode/EIS spectroscopic observations reveal blueshifts at the feet of both sets of loops. The evolution and dynamics of the two sets are quite different. The first set of loops exhibits blueshifts for about 25 minutes followed by redshifts, while the second set shows stronger blueshifts, which are maintained for about one hour. The UV 1600 observation by AIA also shows that the feet of the second set of loops brighten twice. These suggest that continuous heating may be present in the second set of loops. We use spatially resolved UV light curves to infer heating rates in the few tens of individual loops comprising the two loop systems. With these heating rates, we then compute plasma evolution in these loops with the "enthalpy-based thermal evolution of loops" (EBTEL) model. The results show that, for the first set of loops, the synthetic EU...

  10. Simulation and optimization of beam losses during continuous transfer extraction at the CERN Proton Synchrotron

    E-Print Network [OSTI]

    Garcia, J B

    2011-01-01T23:59:59.000Z

    The proton beams used for the fixed target physics at the Super Proton Synchrotron (SPS) are extracted from the Proton Synchrotron ( PS) by a multiturn technique called continuous transfer (CT). During the CT extraction, large losses are observed in locations where the machine aperture should be large enough to accommodate the circulating beam. This limits the maximum intensity deliverable due to the induced stray radiation outside the PS tunnel. Scattered particles from the interaction with the electrostatic septum are identified as the possible source of these losses. This article presents a detailed study aiming to understand the origin of losses and propose possible cures. The simulations could reproduce accurately the beam loss pattern measured in real machine operation and determine the beam shaving, intrinsic to the extraction process, as the cause for the unexpected losses. Since these losses are unavoidable, the proposed solution implies a new optics scheme displacing the losses to a region with bett...

  11. Painted Ponies: Essays on Memory and Loss

    E-Print Network [OSTI]

    Klayder, Mary

    2008-12-30T23:59:59.000Z

    This collection explores the spiral nature of memory as it examines the way loss and one's reactions to loss repeat themselves in new guises and new contexts. Interspersing poetry with essays of memoir, Klayder examines ...

  12. Loss mechanisms in turbine tip clearance flows

    E-Print Network [OSTI]

    Huang, Arthur (Arthur C.)

    2011-01-01T23:59:59.000Z

    Numerical simulations of tip clearance ow have been carried out to dene the loss generation mechanisms associated with tip leakage in unshrouded axial turbines. Mix- ing loss between the leakage, which takes the form of a ...

  13. Loss of coordination in competitive supply chains

    E-Print Network [OSTI]

    Teo, Koon Soon

    2009-01-01T23:59:59.000Z

    The loss of coordination in supply chains quantifies the inefficiency (i.e. the loss of total profit) due to the presence of competition in the supply chain. In this thesis, we discuss four models: one model with multiple ...

  14. Induction machine stray loss from inter-bar currents

    E-Print Network [OSTI]

    Englebretson, Steven Carl

    2009-01-01T23:59:59.000Z

    Stray load loss refers generally to the sources of induction machine loss not accounted for by typical calculations of primary or secondary copper loss, no load core loss, or friction and windage loss. Harmonic rotor bar ...

  15. New Beam Loss Monitor for 12 GeV Upgrade

    SciTech Connect (OSTI)

    Jianxun Yan, Kelly Mahoney

    2009-10-01T23:59:59.000Z

    This paper describes a new VME based machine protection Beam Loss Monitor (BLM) signal processing board designed at Jefferson Lab to replace the current CAMAC based BLM board. The new eight-channel BLM signal processor has linear, logarithmic, and integrating amplifiers that simultaneously provide the optimal signal processing for each application. Amplified signals are digitized and then further processed through a Field Programmable Gate Array (FPGA). Combining both the diagnostic and machine protection functions in each channel allows the operator to tune-up and monitor beam operations while the machine protection is integrating the same signal. Other features include extensive built-in-self-test, fast shutdown interface (FSD), and 16-Mbit buffers for beam loss transient play-back. The new VME BLM board features high sensitivity, high resolution, and low cost per channel.

  16. X-Ray Flares of Sun-Like Young Stellar Objects and Their Effects on Protoplanetary Disks

    E-Print Network [OSTI]

    A. E. Glassgold; E. D. Feigelson; T. Momtmerle; S. Wolk

    2005-06-13T23:59:59.000Z

    Astronomical observations of flares from analogs of the early Sun have the potential to give critical insights into the high energy irradiation environment of protoplanetary disks. Solar-mass young stellar objects are significantly more X-ray luminous than the typical low-mass T Tauri star. They undergo frequent strong flaring on a several day time scale. Very powerful flares also occur, but on a longer time frame. The hard X-ray spectrum of these stars become even harder during flaring. The X-rays from these sun-like young stellar objects have the potential to ionize circumstellar material out to large distances. Three specific illustrations are given of the effects of the X-rays: The physics and chemistry of the atmospheres of the inner accretion disks; the ionization level at the disk midplane, important for the viability of the magnetorotational instability; and the nuclear fluence in the irradiation zone just interior to the inner edge of the disk, important in local irradiation scenarios for producing the short-lived radionuclides found in meteorites.

  17. Stellar flares observed by LOFT: implications for the physics of coronae and for the "space weather" environment of extrasolar planets

    E-Print Network [OSTI]

    Drake, S A; Doyle, J G; Güdel, M; Hamaguchi, K; Kowalski, A F; Maccarone, T; Osten, R A; Peretz, U; Wolk, S J

    2015-01-01T23:59:59.000Z

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of stellar flares. For a summary, we refer to the paper.

  18. Global analysis of active longitudes of solar X-ray flares L. Zhang a,b,c

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    Observatories, Chinese Academy of Sciences, Beijing, China c Key Laboratory of Solar Activity, Chinese AcademyGlobal analysis of active longitudes of solar X-ray flares L. Zhang a,b,c , K. Mursula a,Ã, I of Sciences, Beijing, China d University of Oulu, Sodankyl¨a Geophysical Observatory, Oulu, Finland a r t i c

  19. STUDIES OF SOLAR WHITE-LIGHT FLARES AND SMALL-SCALE MAGNETIC STRUCTURES OBSERVED IN THE NEAR INFRARED

    E-Print Network [OSTI]

    IN THE NEAR INFRARED by Yan Xu Using the most advanced infrared imaging technology as developed by NJIT, are presented in this dissertation. The investigations focus on near-infrared observations at 1.56 µm, which of near infrared (NIR) solar physics: (1) the first detection and understanding of white-light flares

  20. A close-up of the Sun (shown in ultraviolet light) reveals a mottled surface, bright flares,

    E-Print Network [OSTI]

    Christian, Eric

    #12;#12;A close-up of the Sun (shown in ultraviolet light) reveals a mottled surface, bright flares, and tongues of hot gas leaping into space. Though they look like burns in the face of the Sun, sunspots circle in the center of the photo--allows scientists to see the solar wind streaming away from the Sun

  1. Configuration and Validation of the LHC Beam Loss Monitoring System

    E-Print Network [OSTI]

    Zamantzas, C; Emery, J; Fitzek, J; Follin, F; Jackson, S; Kain, V; Kruk, G; Misiowiec, M; Roderick, C; Sapinski, M

    2009-01-01T23:59:59.000Z

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. As well as protecting the machine, the system is also used as a means of diagnosing machine faults, and providing feedback of losses to the control room and several systems such as the Collimation, the Beam Dump and the Post-Mortem. The system has to transmit and process signals from over 4’000 monitors, and has approaching 3 million configurable parameters. This paper describes the types of configuration data needed, the means used to store and deploy all the parameters in such a distributed system and how operators are able to alter the operating parameters of the system, particularly with regard to the loss threshold values. The various security mechanisms put in place, both at the hardware and software level, to avoid accidental or malicious modification of these BLM parameters are also shown for each case.

  2. Acceleration of the Greenland ice sheet mass loss as observed by GRACE: Confidence and sensitivity

    E-Print Network [OSTI]

    Acceleration of the Greenland ice sheet mass loss as observed by GRACE: Confidence and sensitivity: Greenland mass loss acceleration confidence intervals GRACE a b s t r a c t We examine the scale and spatial distribution of the mass change acceleration in Greenland and its statistical significance, using processed

  3. Influence of parasitic resistances on the mismatch relative power loss of solar cell modules

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    689 Influence of parasitic resistances on the mismatch relative power loss of solar cell modules P, which originate from the manufacturing process. In order to enhance the array output power, the cells, to a limited extent, for mmRPL of a parallel-connected module. 1. Introduction. Loss of output power from

  4. Reducing Data Loss and Saving Money by Acquiring Data Loss Prevention Software

    E-Print Network [OSTI]

    Schaefer, Marcus

    Reducing Data Loss and Saving Money by Acquiring Data Loss Prevention Software Master of Art data loss and saving money by acquiring DLP software Patarika Tipwong Acknowledgements This thesisPaul University. #12;Reducing data loss and saving money by acquiring DLP software Patarika Tipwong Table

  5. SIMULATION OF DESCENDING MULTIPLE SUPRA-ARCADE RECONNECTION OUTFLOWS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Cecere, M.; Schneiter, M.; Costa, A.; Elaskar, S. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Maglione, S. [Facultad de Ingenieria, Universidad Nacional de Rio Cuarto, Rio Cuarto, Cordoba (Argentina)

    2012-11-10T23:59:59.000Z

    After recent Atmospheric Imaging Assembly observations by Savage, McKenzie, and Reeves, we revisit the scenario proposed by us in previous papers. We have shown that sunward, generally dark plasma features that originated above posteruption flare arcades are consistent with a scenario where plasma voids (which we identify as supra-arcade reconnection outflows, SAROs) generate the bouncing and interfering of shocks and expansion waves upstream of an initial localized deposition of energy that is collimated in the magnetic field direction. In this paper, we analyze the multiple production and interaction of SAROs and their individual structures that make them relatively stable features while moving. We compare our results with observations and with the scenarios proposed by other authors.

  6. Limits to Quantum Gravity Effects from Observations of TeV Flares in Active Galaxies

    E-Print Network [OSTI]

    S. D. Biller; A. C. Breslin; J. Buckley; M. Catanese; M. Carson; D. A. Carter-Lewis; M. F. Cawley; D. J. Fegan; J. Finley; J. A. Gaidos; A. M. Hillas; F. Krennrich; R. C. Lamb; R. Lessard; C. Masterson; J. E. McEnery; B. McKernan; P. Moriarty; J. Quinn; H. J. Rose; F. Samuelson; G. Sembroski; P. Skelton; T. C. Weekes

    1998-10-13T23:59:59.000Z

    We have used data from the TeV gamma-ray flare associated with the active galaxy Markarian 421 observed on 15 May 1996 to place bounds on the possible energy-dependence of the speed of light in the context of an effective quantum gravitational energy scale. The possibility of an observable time dispersion in high energy radiation has recently received attention in the literature, with some suggestions that the relevant energy scale could be less than the Planck mass and perhaps as low as 10^16 GeV. The limits derived here indicate this energy scale to be in excess of 4x10^16 GeV at the 95% confidence level. To the best of our knowledge, this constitutes the first convincing limit on such phenomena in this energy regime.

  7. ON THE CAUSE OF SUPRA-ARCADE DOWNFLOWS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Cassak, P. A.; Shepherd, L. S. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States)] [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Drake, J. F. [Department of Physics and the Institute for Physical Science and Technology and the Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States)] [Department of Physics and the Institute for Physical Science and Technology and the Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Gosling, J. T. [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO 80303 (United States)] [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO 80303 (United States); Phan, T.-D. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)] [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Shay, M. A., E-mail: Paul.Cassak@mail.wvu.edu, E-mail: lshephe1@mix.wvu.edu, E-mail: drake@umd.edu, E-mail: Jack.Gosling@lasp.colorado.edu, E-mail: phan@ssl.berkeley.edu, E-mail: shay@udel.edu [Department of Physics and Astronomy, University of Delaware, Newark, DE 20742 (United States)

    2013-09-20T23:59:59.000Z

    A model of supra-arcade downflows (SADs), dark low density regions also known as tadpoles that propagate sunward during solar flares, is presented. It is argued that the regions of low density are flow channels carved by sunward-directed outflow jets from reconnection. The solar corona is stratified, so the flare site is populated by a lower density plasma than that in the underlying arcade. As the jets penetrate the arcade, they carve out regions of depleted plasma density which appear as SADs. The present interpretation differs from previous models in that reconnection is localized in space but not in time. Reconnection is continuous in time to explain why SADs are not filled in from behind as they would if they were caused by isolated descending flux tubes or the wakes behind them due to temporally bursty reconnection. Reconnection is localized in space because outflow jets in standard two-dimensional reconnection models expand in the normal (inflow) direction with distance from the reconnection site, which would not produce thin SADs as seen in observations. On the contrary, outflow jets in spatially localized three-dimensional reconnection with an out-of-plane (guide) magnetic field expand primarily in the out-of-plane direction and remain collimated in the normal direction, which is consistent with observed SADs being thin. Two-dimensional proof-of-principle simulations of reconnection with an out-of-plane (guide) magnetic field confirm the creation of SAD-like depletion regions and the necessity of density stratification. Three-dimensional simulations confirm that localized reconnection remains collimated.

  8. CHROMOSPHERIC EVAPORATION IN AN M1.8 FLARE OBSERVED BY THE EXTREME-ULTRAVIOLET IMAGING SPECTROMETER ON HINODE

    SciTech Connect (OSTI)

    Doschek, G. A.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Young, P. R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)] [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2013-04-10T23:59:59.000Z

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s{sup -1} upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s{sup -1} upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s{sup -1}. We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive tests of models of chromospheric evaporation as envisaged in the Standard Flare Model.

  9. Analysis of TPV Network Losses (a Presentation)

    SciTech Connect (OSTI)

    DM DePoy; MW Dashiell; DD Rahner; LR Danielson; JE Oppenlander; JL Vell; RJ Wehrer

    2004-12-08T23:59:59.000Z

    This talk focuses on the theoretical analysis of electrical losses associated with electrically networking large numbers of TPV cells to produce high power TPV power generators.

  10. A New Loss Control Management System; Assimilating Loss Control Methodology in Reducing the Overall Quality Losses in XYZ Chemical Corporation

    E-Print Network [OSTI]

    Shaikh, Sameer

    2011-05-20T23:59:59.000Z

    that has occurred in recent past. While the quality management system that is in place at XYZ monitors and improves the overall quality of the products, it does not capture the quality losses as it should. Quality losses occur due to human error...

  11. Method for reducing energy losses in laser crystals

    DOE Patents [OSTI]

    Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.

    1992-03-24T23:59:59.000Z

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.

  12. Statistical methods for detecting loss of materials using NRTA data

    SciTech Connect (OSTI)

    Burr, T.; Coulter, A.; Hakkila, A. [Los Alamos National Lab., NM (United States); Ai, H.; Kadokura, I.; Fujimaki, K. [Japan Nuclear Fuel Ltd., Tokyo (Japan)

    1995-12-31T23:59:59.000Z

    The authors selected eight sequential statistical tests and studied their performance on near-real-time-accounting (NRTA) data that is nominally what is expected from the proposed Rokkasho Reprocessing Plant in Japan. The effort divided into three main activities: (1) use process-flow information to determine process vessel inventories and transfers at the time of material balance closure, (2) use variance propagation methods to estimate the variance-covariance matrix of a sequence of material balances, and (3) study the performance of eight sequential tests on a variety of loss scenarios. This paper describes the results of these three activities.

  13. A JOINT ANALYSIS OF HIGH-ENERGY NEUTRONS AND NEUTRON-l)ECAY PROTONS FROM A FLARE

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    A JOINT ANALYSIS OF HIGH-ENERGY NEUTRONS AND NEUTRON-l)ECAY PROTONS FROM A FLARE I.. G. KOCI'l.I)elel:sl~zHg 194021. RHs.ffa (Received ll April, 19%; in final form 19.1uly., 1996) Abstract. A .joint. analysis of the 1990 May 24 neutron event provided an oppor u ~ ly to delect neu[ron decay prolons of higher energies

  14. Compton backscattered and primary X-rays from solar flares: angle dependent Green's function correction for photospheric albedo

    E-Print Network [OSTI]

    Eduard P. Kontar; Alec L. MacKinnon; Richard A. Schwartz; John C. Brown

    2005-10-06T23:59:59.000Z

    The observed hard X-ray (HXR) flux spectrum $I(\\epsilon)$ from solar flares is a combination of primary bremsstrahlung photons $I_P(\\epsilon)$ with a spectrally modified component from photospheric Compton backscatter of downward primary emission. The latter can be significant, distorting or hiding the true features of the primary spectrum which are key diagnostics for acceleration and propagation of high energy electrons and of their energy budget. For the first time in solar physics, we use a Green's function approach to the backscatter spectral deconvolution problem, constructing a Green's matrix including photoelectric absorption. This approach allows spectrum-independent extraction of the primary spectrum for several HXR flares observed by the {\\it Ramaty High Energy Solar Spectroscopic Imager} (RHESSI). We show that the observed and primary spectra differ very substantially for flares with hard spectra close to the disk centre. We show in particular that the energy dependent photon spectral index $\\gamma (\\epsilon)=-d \\log I/d \\log \\epsilon$ is very different for $I_P(\\epsilon)$ and for $I(\\epsilon)$ and that inferred mean source electron spectra ${\\bar F}(E)$ differ greatly. Even for a forward fitting of a parametric ${\\bar F}(E)$ to the data, a clear low-energy cutoff required to fit $I(\\epsilon)$ essentially disappears when the fit is to $I_P(\\epsilon)$ - i.e. when albedo correction is included. The self-consistent correction for backscattered photons is thus shown to be crucial in determining the energy spectra of flare accelerated electrons, and hence their total number and energy.

  15. Handling Food and Supplies during Power Loss

    E-Print Network [OSTI]

    Anding, Jenna

    2005-09-30T23:59:59.000Z

    ER-017 6-06 Loss of electricity or gas commonly occurs during storms or other natural disasters. However, power loss may continue for weeks after the storm has passed, especially if an area has been damaged by floods or high winds. If you...

  16. MANAGING JOB LOSS and FINANCIAL STRESS

    E-Print Network [OSTI]

    -hunting strategy. Put time and energy into planning actions that will lead to your next job such as preparingMANAGING JOB LOSS and FINANCIAL STRESS a Personal and Family Guide CENTER ON THE FAMILY #12;2 Managing Job Loss and Financial Stress The issues associated with losing one's job or having hours cut

  17. Support vector machines with the ramp loss and the hard margin loss

    E-Print Network [OSTI]

    J.P. Brooks

    2008-11-04T23:59:59.000Z

    Nov 4, 2008 ... Support vector machines with the ramp loss and the hard margin loss. J.P. Brooks (jpbrooks ***at*** vcu.edu). Abstract: In the interest of ...

  18. CLASSICAL CEPHEIDS REQUIRE ENHANCED MASS LOSS

    SciTech Connect (OSTI)

    Neilson, Hilding R.; Langer, Norbert; Izzard, Robert [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Engle, Scott G.; Guinan, Ed, E-mail: neilsonh@etsu.edu [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Ave. Villanova, PA 19085 (United States)

    2012-11-20T23:59:59.000Z

    Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools for measuring the Hubble constant. Our recent study of the period change of the nearest Cepheid, Polaris, suggested that it is undergoing enhanced mass loss when compared to canonical stellar evolution model predictions. In this work, we expand the analysis to rates of period change measured for about 200 Galactic Cepheids and compare them to population synthesis models of Cepheids including convective core overshooting and enhanced mass loss. Rates of period change predicted from stellar evolution models without mass loss do not agree with observed rates, whereas including enhanced mass loss yields predicted rates in better agreement with observations. This is the first evidence that enhanced mass loss as suggested previously for Polaris and {delta} Cephei must be a ubiquitous property of Classical Cepheids.

  19. High energy astrophysical processes

    E-Print Network [OSTI]

    Todor Stanev

    2005-04-18T23:59:59.000Z

    We briefly review the high energy astrophysical processes that are related to the production of high energy $\\gamma$-ray and neutrino signals and are likely to be important for the energy loss of high and ultrahigh energy cosmic rays. We also give examples for neutrino fluxes generated by different astrophysical objects and describe the cosmological link provided by cosmogenic neutrinos.

  20. Three-dimensional Magnetic Restructuring in Two Homologous Solar Flares in the Seismically Active NOAA AR 11283

    E-Print Network [OSTI]

    Liu, Chang; Lee, Jeongwoo; Wiegelmann, Thomas; Jiang, Chaowei; Dennis, Brian R; Su, Yang; Donea, Alina; Wang, Haimin

    2014-01-01T23:59:59.000Z

    We carry out a comprehensive investigation comparing the three-dimensional magnetic field restructuring, flare energy release, and the helioseismic response, of two homologous flares, the 2011 September 6 X2.1 (FL1) and September 7 X1.8 (FL2) flares in NOAA AR 11283. In our analysis, (1) a twisted flux rope (FR) collapses onto the surface at a speed of 1.5 km/s after a partial eruption in FL1. The FR then gradually grows to reach a higher altitude and collapses again at 3 km/s after a fuller eruption in FL2. Also, FL2 shows a larger decrease of the flux-weighted centroid separation of opposite magnetic polarities and a greater change of the horizontal field on the surface. These imply a more violent coronal implosion with corresponding more intense surface signatures in FL2. (2) The FR is inclined northward, and together with the ambient fields, it undergoes a southward turning after both events. This agrees with the asymmetric decay of the penumbra observed in the peripheral regions. (3) The amounts of free ...

  1. PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS FROM THE SWIFT X-RAY TELESCOPE OBSERVATIONS

    E-Print Network [OSTI]

    Zhang, Bing

    PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS August 15; accepted 2005 December 19 ABSTRACT With the successful launch of the Swift Gamma-Ray Burst component is consistent with the tail emission of the prompt gamma-ray bursts and/or the X-ray flares

  2. MULTI-WAVELENGTH OBSERVATIONS OF THE SPATIO-TEMPORAL EVOLUTION OF SOLAR FLARES WITH AIA/SDO. I. UNIVERSAL SCALING LAWS OF SPACE AND TIME PARAMETERS

    SciTech Connect (OSTI)

    Aschwanden, Markus J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304 (United States); Zhang, Jie; Liu, Kai, E-mail: aschwanden@lmsal.com, E-mail: jzhang7@gmu.edu [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Dr., MSN 6A2, Fairfax, VA 22030 (United States)

    2013-09-20T23:59:59.000Z

    We extend a previous statistical solar flare study of 155 GOES M- and X-class flares observed with AIA/SDO to all seven coronal wavelengths (94, 131, 171, 193, 211, 304, and 335 Å) to test the wavelength dependence of scaling laws and statistical distributions. Except for the 171 and 193 Å wavelengths, which are affected by EUV dimming caused by coronal mass ejections (CMEs), we find near-identical size distributions of geometric (lengths L, flare areas A, volumes V, and fractal dimension D{sub 2}), temporal (flare durations T), and spatio-temporal parameters (diffusion coefficient ?, spreading exponent ?, and maximum expansion velocities v{sub max}) in different wavelengths, which are consistent with the universal predictions of the fractal-diffusive avalanche model of a slowly driven, self-organized criticality (FD-SOC) system, i.e., N(L)?L {sup –3}, N(A)?A {sup –2}, N(V)?V {sup –5/3}, N(T)?T {sup –2}, and D{sub 2} = 3/2, for a Euclidean dimension d = 3. Empirically, we find also a new strong correlation ??L {sup 0.94±0.01} and the three-parameter scaling law L?? T {sup 0.1}, which is more consistent with the logistic-growth model than with classical diffusion. The findings suggest long-range correlation lengths in the FD-SOC system that operate in the vicinity of a critical state, which could be used for predictions of individual extreme events. We find also that eruptive flares (with accompanying CMEs) have larger volumes V, longer flare durations T, higher EUV and soft X-ray fluxes, and somewhat larger diffusion coefficients ? than confined flares (without CMEs)

  3. A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the Rho Ophiuchi Star-Forming Region with Chandra

    E-Print Network [OSTI]

    K. Imanishi; H. Nakajima; M. Tsujimoto; K. Koyama; Y. Tsuboi

    2003-05-10T23:59:59.000Z

    We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using Chandra observations of the main region of the Rho Oph. From 195 X-ray sources, including class I-III sources and some young brown dwarfs, we detected a total of 71 X-ray flares. Most of the flares have the typical profile of solar and stellar flares, fast rise and slow decay. We derived the time-averaged temperature (kT), luminosity (L_X), rise and decay timescales (tau_r and tau_d) of the flares, finding that (1) class I-II sources tend to have a high kT, (2) the distribution of L_X during flares is nearly the same for all classes, and (3) positive and negative log-linear correlations are found between tau_r and tau_d, and kT and tau_r. In order to explain these relations, we used the framework of magnetic reconnection model to formulate the observational parameters as a function of the half-length of the reconnected magnetic loop (L) and magnetic field strength (B). The estimated L is comparable to the typical stellar radius of these objects (10^{10-11} cm), which indicates that the observed flares are triggered by solar-type loops, rather than larger ones (10^{12} cm) connecting the star with its inner accretion disk. The higher kT observed for class I sources may be explained by a higher magnetic field strength (about 500 G) than for class II-III sources (200-300 G).

  4. PARTICLE ACCELERATION IN FRAGMENTING PERIODIC RECONNECTING CURRENT SHEETS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Gordovskyy, M.; Browning, P. K.; Vekstein, G. E., E-mail: mykola.gordovskyy@manchester.ac.u [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

    2010-09-10T23:59:59.000Z

    Proton and electron acceleration in a fragmenting periodic current sheet (CS) is investigated, based on the forced magnetic reconnection scenario. The aim is to understand the role of CS fragmentation in high-energy beam generation in solar flares. We combine magnetohydrodynamics and test-particle models to consider particle trajectories consistent with a time-dependent reconnection model. It is shown that accelerated particles in such a model form two distinct populations. Protons and electrons moving in open magnetic field have energy spectra that are a combination of the initial Maxwellian distribution and a power-law high-energy (E>20 keV) part. The second population contains particles moving in a closed magnetic field around O-points. These particles move predominantly along the guiding field and their energies fall within quite a narrow range between {approx}1 MeV and {approx}10 MeV. It is also found that particles moving in an open magnetic field have a considerably wider pitch-angle distribution.

  5. Correlated optical and X-ray flares in the afterglow of XRF 071031

    E-Print Network [OSTI]

    Krühler, T; McBreen, S; Klose, S; Rossi, A; Afonso, P; Clemens, C; Filgas, R; Yoldas, A Küpcü; Szokoly, G P; Yoldas, A

    2009-01-01T23:59:59.000Z

    We present a densely sampled early light curve of the optical/near-infrared (NIR) afterglow of the X-Ray Flash (XRF) 071031 at z=2.692. Simultaneous and continuous observations in seven photometric bands from g' to K with GROND at the 2.2 m MPI/ESO telescope on LaSilla were performed between 4 minutes and 7 hours after the burst. The light curve consists of 547 individual points which allows us to study the early evolution of the optical transient associated with XRF 071031 in great detail. The optical/NIR light curve is dominated by an early increase in brightness which can be attributed to the apparent onset of the forward shock emission. There are several bumps which are superimposed onto the overall rise and decay. Significant flaring is also visible in the Swift X-Ray Telescope (XRT) light curve from early to late times. The availability of high quality, broadband data enables detailed studies of the connection between the X-ray and optical/NIR afterglow and its colour evolution during the first night po...

  6. KAPPA DISTRIBUTION MODEL FOR HARD X-RAY CORONAL SOURCES OF SOLAR FLARES

    SciTech Connect (OSTI)

    Oka, M.; Ishikawa, S.; Saint-Hilaire, P.; Krucker, S.; Lin, R. P. [Space Sciences Laboratory, University of California Berkeley (United States)] [Space Sciences Laboratory, University of California Berkeley (United States)

    2013-02-10T23:59:59.000Z

    Solar flares produce hard X-ray emission, the photon spectrum of which is often represented by a combination of thermal and power-law distributions. However, the estimates of the number and total energy of non-thermal electrons are sensitive to the determination of the power-law cutoff energy. Here, we revisit an 'above-the-loop' coronal source observed by RHESSI on 2007 December 31 and show that a kappa distribution model can also be used to fit its spectrum. Because the kappa distribution has a Maxwellian-like core in addition to a high-energy power-law tail, the emission measure and temperature of the instantaneous electrons can be derived without assuming the cutoff energy. Moreover, the non-thermal fractions of electron number/energy densities can be uniquely estimated because they are functions of only the power-law index. With the kappa distribution model, we estimated that the total electron density of the coronal source region was {approx}2.4 Multiplication-Sign 10{sup 10} cm{sup -3}. We also estimated without assuming the source volume that a moderate fraction ({approx}20%) of electrons in the source region was non-thermal and carried {approx}52% of the total electron energy. The temperature was 28 MK, and the power-law index {delta} of the electron density distribution was -4.3. These results are compared to the conventional power-law models with and without a thermal core component.

  7. Optical polarization map of the Polaris Flare with RoboPol

    E-Print Network [OSTI]

    Panopoulou, G V; Blinov, D; Pavlidou, V; King, O G; Paleologou, E; Ramaprakash, A; Angelakis, E; Balokovic, M; Das, H K; Feiler, R; Hovatta, T; Khodade, P; Kiehlmann, S; Kus, A; Kylafis, N; Liodakis, I; Modi, D; Myserlis, I; Papadakis, I; Papamastorakis, I; Pazderska, B; Pazderski, E; Pearson, T J; Rajarshi, C; Readhead, A C S; Reig, P; Zensus, J A

    2015-01-01T23:59:59.000Z

    The stages before the formation of stars in molecular clouds are poorly understood. Insights can be gained by studying the properties of quiescent clouds, such as their magnetic field structure. The plane-of-the-sky orientation of the field can be traced by polarized starlight. We present the first extended, wide-field ($\\sim$10 $\\rm deg^2$) map of the Polaris Flare cloud in dust-absorption induced optical polarization of background stars, using the RoboPol polarimeter at the Skinakas Observatory. This is the first application of the wide-field imaging capabilities of RoboPol. The data were taken in the R-band and analysed with the automated reduction pipeline of the instrument. We present in detail optimizations in the reduction pipeline specific to wide-field observations. Our analysis resulted in reliable measurements of 648 stars with median fractional linear polarization 1.3%. The projected magnetic field shows a large scale ordered pattern. At high longitudes it appears to align with faint striations se...

  8. On the variation of solar flare coronal x-ray source sizes with energy

    E-Print Network [OSTI]

    Jeffrey, Natasha L S; Bian, Nicolas H; Emslie, A Gordon

    2014-01-01T23:59:59.000Z

    Observations with {\\em RHESSI} have enabled the detailed study of the structure of dense hard X-ray coronal sources in solar flares. The variation of source extent with electron energy has been discussed in the context of streaming of non-thermal particles in a one-dimensional cold-target model, and the results used to constrain both the physical extent of, and density within, the electron acceleration region. Here we extend this investigation to a more physically realistic model of electron transport that takes into account the finite temperature of the ambient plasma, the initial pitch-angle distribution of the accelerated electrons, and the effects of collisional pitch-angle scattering. The finite temperature results in the thermal diffusion of electrons, that leads to the observationally-inferred value of the acceleration region volume being an overestimate of its true value. The different directions of the electron trajectories, a consequence of both the non-zero injection pitch-angle and scattering with...

  9. Optimization of quantum interferometric metrological sensors in the presence of photon loss

    E-Print Network [OSTI]

    Tae-Woo Lee; Sean D. Huver; Hwang Lee; Lev Kaplan; Steven B. McCracken; Changjun Min; Dmitry B. Uskov; Christoph F. Wildfeuer; Georgios Veronis; Jonathan P. Dowling

    2009-08-20T23:59:59.000Z

    We optimize two-mode, entangled, number states of light in the presence of loss in order to maximize the extraction of the available phase information in an interferometer. Our approach optimizes over the entire available input Hilbert space with no constraints, other than fixed total initial photon number. We optimize to maximize the Fisher information, which is equivalent to minimizing the phase uncertainty. We find that in the limit of zero loss the optimal state is the so-called N00N state, for small loss, the optimal state gradually deviates from the N00N state, and in the limit of large loss the optimal state converges to a generalized two-mode coherent state, with a finite total number of photons. The results provide a general protocol for optimizing the performance of a quantum optical interferometer in the presence of photon loss, with applications to quantum imaging, metrology, sensing, and information processing.

  10. Telling Absence: War Widows, Loss and Memory 

    E-Print Network [OSTI]

    Loipponen, Jaana

    2009-01-01T23:59:59.000Z

    This thesis concerns feminist sociological analysis of war loss and its consequences as experienced and told by Finnish Karelian war widows of World War 2. They lost their partners and had to leave their homes by force, ...

  11. Corona losses in HVdc bipolar lines

    SciTech Connect (OSTI)

    Corbellini, U.; Pelacchi, P. [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation] [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation

    1996-07-01T23:59:59.000Z

    The problem related to the prediction of corona losses in HVdc bipolar lines has been solved, in the past, by means of semi-empirical monomial formulae. However, the proposed formulae that are simpler to use do not always give adequate calculation precision, while the formulae that provide the closest results require implicit functions of different complexity, which are difficult to apply; moreover, it is not possible to understand clearly what influence the variations of the different line parameters have on the losses themselves. The new monomial semi-empirical relationship, proposed to predict the corona losses in HVdc bipolar lines, is very simple to use; it highlights the dependence of power losses due to the corona effect by the different line parameters. The formula has been developed by elaborating a considerable amount of available experimental data.

  12. Report on fuel pool water loss tests

    SciTech Connect (OSTI)

    Zalenski, R.F. [West Valley Nuclear Services Co., West Valley, NY (United States)

    1995-12-31T23:59:59.000Z

    To resolve potential concerns on the integrity of the fuel storage pool at the West Valley Demonstration Project (WVDP), a highly accurate testing technique was developed to quantify water losses from the pool. The fuel pool is an unlined, single wall, reinforced concrete structure containing approximately 818,000 gallons of water. Since an initial test indicated that water losses could possibly be attributed solely to evaporation, a cover was suspended and sealed over the pool to block evaporation losses. High accuracy water level and temperature instrumentation was procured and installed. The conclusions of this report indicate that unaccounted-for water losses from the pool are insignificant and there is no detectable leakage within the range of test accuracy.

  13. Nuclear parton distribution functions and energy loss effect in the Drell-Yan reaction off nuclei

    E-Print Network [OSTI]

    ChunGui Duan; LiHua Song; ShuoHe Wang; GuangLie Li

    2006-01-23T23:59:59.000Z

    The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of two typical kinds of quark energy loss parametrization and the different sets of nuclear parton distribution functions, we present a analysis of the E866 experiments on the nuclear dependence of Drell-Yan lepton pair production resulting from the bombardment of Be, Fe and W targets by 800GeV protons at Fermilab. It is found that the quark energy loss in cold nuclei is strongly dependent on the used nuclear parton distribution functions. The further prospects of using relatively low energy proton incident on nuclear targets are presented by combining the quark energy loss rate determined from a fit to the E866 nuclear-dependent ratios versus $x_1$, with the nuclear parton distribution functions given from lA deep inelastic scattering (DIS) data. The experimental study of the relatively low energy nuclear Drell-Yan process can give valuable insight in the enengy loss of fast quark propagating a cold nuclei and help to pin down nuclear parton distributions functions.

  14. X-rays From Magnetic Flares In Cygnus X-1: A Unified Model With Seyfert Galaxies

    E-Print Network [OSTI]

    Sergei Nayakshin; Fulvio Melia

    1998-02-11T23:59:59.000Z

    Some recent work has shown that the spectrum of Seyfert 1 Galaxies is very similar to that of several Galactic Black Hole Candidates (GBHCs) in their hard state. However, the smallness of the observed reflection component in Cygnus X-1, in addition to other constraints, seem to rule out the two-phase model (otherwise successful in the case of Seyfert Galaxies) for GBHCs. Here, we show that the latter conclusion is based on a number of key assumptions that probably are not valid when the overlying corona is patchy, e.g., when it is comprised of localized magnetic flares above the disk. We show that in GBHCs the energy deposited by the X-rays cannot be re-radiated fast enough to maintain equilibrium, unless the X-ray skin heats up to the Compton temperature, at which point the gas is mostly ionized. This leads to a substantially reduced cooling rate for the active regions due to the correspondingly smaller number of re-injected low-energy photons. We model this effect by introducing a transition layer situated between the corona and the cold disk, and find that the resulting spectrum is harder than that obtained with the standard (and unrealistic) two-phase model. We apply this model to Cygnus X-1 and show that it can account for its observed spectrum. This analysis therefore seems to provide a consistentpicture for both Seyfert Galaxies and GBHCs within the same framework, with differences arising due to the changing physical conditionsin the two categories of sources, rather than due to an ad hoc variation of the model parameters.

  15. Fermi Guest Investigator Program Cycle 2 Project Final Report Albedo Polarimetry of Gamma-Ray Bursts and Solar Flares with GBM

    SciTech Connect (OSTI)

    Kippen, Richard Marc [Los Alamos National Laboratory

    2012-08-27T23:59:59.000Z

    Several key properties of GRBs remain poorly understood and are difficult or even impossible to infer with the information currently being collected. Polarization measurements will probe the precise nature of the central engine. For solar flares, high-energy polarization measurements are expected to be useful in determining the beaming (or directivity) of solar flare electrons - a quantity that may provide important clues about electron acceleration and transport. We propose to investigate the viability of using the Fermi Gamma-ray Burst Monitor (GBM) to measure the polarization of GRBs and solar flares using the albedo photon flux. This approach was previously developed for use with BATSE data. We will conduct a careful study of this technique using a modified version of the GRESS simulation tools developed by the GBM team.

  16. TIME DELAYS IN QUASI-PERIODIC PULSATIONS OBSERVED DURING THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15

    SciTech Connect (OSTI)

    Dolla, L.; Marque, C.; Seaton, D. B.; Dominique, M.; Berghmans, D.; Cabanas, C.; De Groof, A.; Verdini, A.; West, M. J.; Zhukov, A. N. [Solar-Terrestrial Center of Excellence, Royal Observatory of Belgium, Avenue Circulaire 3, B-1180 Brussels (Belgium); Van Doorsselaere, T. [Centrum voor Plasma-Astrofysica, Department of Mathematics, KULeuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Schmutz, W. [Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos Dorf (Switzerland); Zender, J., E-mail: dolla@sidc.be [European Space Agency, ESTEC, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands)

    2012-04-10T23:59:59.000Z

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on timescale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the extreme-ultraviolet (EUV) channels of the Euv SpectroPhotometer (ESP) on board the Solar Dynamic Observatory. The zirconium and aluminum filter channels of the Large Yield Radiometer on board the Project for On-Board Autonomy satellite and the soft X-ray (SXR) channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite, where the channel at 1-8 A leads the 0.5-4 A channel by several seconds. The time lags between the first and last channels is up to Almost-Equal-To 9 s. We identified at least two distinct time intervals during the flare impulsive phase, during which the QPPs were associated with two different sources in the Nobeyama RadioHeliograph at 17 GHz. The radio as well as the hard X-ray channels showed different lags during these two intervals. To our knowledge, this is the first time that time lags are reported between EUV and SXR fluctuations on these timescales. We discuss possible emission mechanisms and interpretations, including flare electron trapping.

  17. VLBI OBSERVATIONS OF THE JET IN M 87 DURING THE VERY HIGH ENERGY {gamma}-RAY FLARE IN 2010 APRIL

    SciTech Connect (OSTI)

    Hada, Kazuhiro; Giroletti, Marcello; Giovannini, Gabriele [INAF Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Kino, Motoki; Nagai, Hiroshi [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Doi, Akihiro [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara 252-5210 (Japan); Hagiwara, Yoshiaki; Honma, Mareki; Kawaguchi, Noriyuki [Department of Astronomical Science, Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2012-11-20T23:59:59.000Z

    We report on the detailed radio status of the M 87 jet during the very high energy (VHE) {gamma}-ray flaring event in 2010 April, obtained from high-resolution, multi-frequency, phase-referencing Very Long Baseline Array observations. We especially focus on the properties of the jet base (the radio core) and the peculiar knot HST-1, which are currently favored as the {gamma}-ray emitting sites. During the VHE flaring event, the HST-1 region remains stable in terms of its structure and flux density in the optically thin regime above 2 GHz, being consistent with no signs of enhanced activities reported at X-ray for this feature. The radio core shows an inverted spectrum at least up to 43 GHz during this event. Astrometry of the core position, which is specified as {approx}20 R {sub s} from the central engine in our previous study, shows that the core position is stable on a level of 4 R {sub s}. The core at 43 and 22 GHz tends to show slightly ({approx}10%) higher flux level near the date of the VHE flux peak compared with the epochs before/after the event. The size of the 43 GHz core is estimated to be {approx}17 R {sub s}, which is close to the size of the emitting region suggested from the observed timescale of rapid variability at VHE. These results tend to favor the scenario that the VHE {gamma}-ray flare in 2010 April is associated with the radio core.

  18. Gas Spring Losses in Linear Clearance Seal Compressors P.B. Bailey, M.W. Dadd, J.S. Reed*

    E-Print Network [OSTI]

    with a clearance seal linear compressor attached to a plain gas spring volume. The static flow through1 Gas Spring Losses in Linear Clearance Seal Compressors P.B. Bailey, M.W. Dadd, J.S. Reed* , C A fundamental loss mechanism in cryocoolers is associated with compression and expansion processes

  19. Effect of collisions and magnetic convergence on electron acceleration and transport in reconnecting twisted solar flare loops

    E-Print Network [OSTI]

    Gordovskyy, M; Kontar, E P; Bian, N H

    2015-01-01T23:59:59.000Z

    We study a model of particle acceleration coupled with an MHD model of magnetic reconnection in unstable twisted coronal loops. The kink instability leads to the formation of helical currents with strong parallel electric fields resulting in electron acceleration. The motion of electrons in the electric and magnetic fields of the reconnecting loop is investigated using a test-particle approach taking into account collisional scattering. We discuss the effects of Coulomb collisions and magnetic convergence near loop footpoints on the spatial distribution and energy spectra of high-energy electron populations and possible implications on the hard X-ray emission in solar flares.

  20. Factors affect offshore production loss control

    SciTech Connect (OSTI)

    Ash, C.S.

    1986-05-12T23:59:59.000Z

    Many aspects of petroleum measurement on an offshore production platform are the same as at an onshore facility, but there are some unique differences. Before going into them it should be noted that even in today's climate of low or declining oil prices that stock loss control is still important. Improving measurement of the quantity of oil transfers can help reduce the amount of stock that is ''unaccounted for'' or lost. As stock loss is reduced, the salable quantity increases, the gross revenue increases, and the net revenue increases. Even in cases where transfers are between two departments of the same company, accurate measurement and proper accountability are required because they often are the basis for determining costs and can thus affect the price that is charged on a later custody transfer. Inefficiencies in intracompany transfers can often hide real losses which may occur during intercompany transfers.

  1. Reducing the losses of optical metamaterials

    SciTech Connect (OSTI)

    Fang, Anan

    2010-12-15T23:59:59.000Z

    The field of metamaterials is driven by fascinating and far-reaching theoretical visions, such as perfect lenses, invisibility cloaking, and enhanced optical nonlinearities. However, losses have become the major obstacle towards real world applications in the optical regime. Reducing the losses of optical metamaterials becomes necessary and extremely important. In this thesis, two approaches are taken to reduce the losses. One is to construct an indefinite medium. Indefinite media are materials where not all the principal components of the permittivity and permeability tensors have the same sign. They do not need the resonances to achieve negative permittivity, {var_epsilon}. So, the losses can be comparatively small. To obtain indefinite media, three-dimensional (3D) optical metallic nanowire media with different structures are designed. They are numerically demonstrated that they are homogeneous effective indefinite anisotropic media by showing that their dispersion relations are hyperbolic. Negative group refraction and pseudo focusing are observed. Another approach is to incorporate gain into metamaterial nanostructures. The nonlinearity of gain is included by a generic four-level atomic model. A computational scheme is presented, which allows for a self-consistent treatment of a dispersive metallic photonic metamaterial coupled to a gain material incorporated into the nanostructure using the finite-difference time-domain (FDTD) method. The loss compensations with gain are done for various structures, from 2D simplified models to 3D realistic structures. Results show the losses of optical metamaterials can be effectively compensated by gain. The effective gain coefficient of the combined system can be much larger than the bulk gain counterpart, due to the strong local-field enhancement.

  2. Parton Energy Loss with Detailed Balance

    E-Print Network [OSTI]

    Enke Wang; Xin-Nian Wang

    2001-06-28T23:59:59.000Z

    Stimulated gluon emission and thermal absorption in addition to induced radiation are considered for an energetic parton propagating inside a quark- gluon plasma. In the presence of thermal gluons, stimulated emission reduces while absorption increases the parton's energy. The net effect is a reduction of the parton energy loss. Though decreasing asymptotically as $T/E$ with the parton energy, the relative reduction is found to be important for intermediate energies. The modified energy dependence of the energy loss will affect the shape of suppression of moderately high $p_T$ hadrons due to jet quenching in high-energy heavy-ion collisions.

  3. Energy Use Loss and Opportunities Analysis: U.S. Manufacturing...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Use Loss and Opportunities Analysis: U.S. Manufacturing & Mining Energy Use Loss and Opportunities Analysis: U.S. Manufacturing & Mining energyuselossopportunitiesanalys...

  4. Understanding Collection-Related Losses in Organic Solar Cells...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Understanding Collection-Related Losses in Organic Solar Cells Home > Research > ANSER Research Highlights > Understanding Collection-Related Losses in Organic Solar Cells...

  5. Draft "Michigan Saves" Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample loan loss reserve agreement between a state or local government and a financial institution setting the terms and conditions of the loan loss reserve fund.

  6. On Optimal Sequential Prediction for General Processes Andrew B. Nobel

    E-Print Network [OSTI]

    Nobel, Andrew

    -stationary processes under p-th power loss p(u, v) = |u-v|p , 1 'th power loss. Andrew Nobel is with the Department of Statistics, University of North Carolina, Chapel'th power loss of the form p(u, v) = |u - v|p, with 1

  7. Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT

    E-Print Network [OSTI]

    Abdo, A A; Ajello, M; Allafort, A; Amin, M A; Baldini, L; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bonamente, E; Borgland, A W; Bregeon, J; Brigida, M; Buehler, R; Bulmash, D; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Cecchi, C; Charles, E; Cheung, C C; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Corbet, R H D; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Drell, P S; Drlica-Wagner, A; Favuzzi, C; Finke, J; Focke, W B; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Grenier, I A; Grove, J E; Guiriec, S; Hadasch, D; Hayashida, M; Hays, E; Hughes, R E; Inoue, Y; Jackson, M S; Jogler, T; Jòhannesson, G; Johnson, A S; Kamae, T; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Mazziotta, M N; Mehault, J; Michelson, P F; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reyes, L C; Ritz, S; Romoli, C; Roth, M; Parkinson, P M Saz; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Takahashi, H; Takeuchi, Y; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Tronconi, V; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S

    2014-01-01T23:59:59.000Z

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity (E>100 MeV) averaged over $\\sim$ 3 years of observations and peaking on 2010 October 14/15 at 2.9 X 10^{50} erg s^{-1}, makes it among the brightest high-redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time delayed variability to follow about 25 days after a primary flare, with flux about a factor 1.5 less. Two large gamma-ray flares of PKS 1830-211 have been detected by the LAT in the considered period and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the gamma rays flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program ...

  8. Direct observation of the energy release site in a solar flare by SDO/AIA, Hinode/EIS and RHESSI

    E-Print Network [OSTI]

    Simões, Paulo J A; Fletcher, Lyndsay

    2015-01-01T23:59:59.000Z

    We present direct evidence for the detection of the main energy release site in a non-eruptive solar flare, SOL2013-11-09T06:38UT. This GOES C2.7 event was characterised by two flaring ribbons and a compact, bright coronal source located between them, which is the focus of our study. We use imaging from SDO/AIA, and imaging spectroscopy from RHESSI to characterise the thermal and non-thermal emission from the coronal source, and EUV spectroscopy from the Hinode/EIS, which scanned the coronal source during the impulsive peak, to analyse Doppler shifts in Fe XII and Fe XXIV emission lines, and determine the source density. The coronal source exhibited an impulsive emission lightcurve in all AIA filters during the impulsive phase. RHESSI hard X-ray images indicate both thermal and non-thermal emission at the coronal source, and its plasma temperature derived from RHESSI imaging spectroscopy shows an impulsive rise, reaching a maximum at 12-13 MK about 10 seconds prior to the hard X-ray peak. High redshifts assoc...

  9. The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT

    E-Print Network [OSTI]

    Abramowski, A; Benkhali, F Ait; Akhperjanian, A G; Angüner, E O; Backes, M; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Tjus, J Becker; Berge, D; Bernhard, S; Bernlöhr, K; Birsin, E; Biteau, J; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Bregeon, J; Brun, F; Brun, P; Bryan, M; Bulik, T; Carrigan, S; Casanova, S; Chadwick, P M; Chakraborty, N; Chalme-Calvet, R; Chaves, R C G; Chrétien, M; Colafrancesco, S; Cologna, G; Conrad, J; Couturier, C; Cui, Y; Dalton, M; Davids, I D; Degrange, B; Deil, C; deWilt, P; Djannati-Ataï, A; Domainko, W; Donath, A; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Edwards, T; Egberts, K; Eger, P; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Fü\\ssling, M; Gabici, S; Gajdus, M; Gallant, Y A; Garrigoux, T; Giavitto, G; Giebels, B; Glicenstein, J F; Gottschall, D; Grondin, M -H; Grudzi?ska, M; Hadsch, D; Häffner, S; Hahn, J; Harris, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Ivascenko, A; Jacholkowska, A; Jahn, C; Jamrozy, M; Janiak, M; Jankowsky, F; Jung, I; Kastendieck, M A; Katarzy?ski, K; Katz, U; Kaufmann, S; Khélifi, B; Kieffer, M; Klepser, S; Klochkov, D; Klu?niak, W; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lefaucheur, J; Lefranc, V; Lemière, A; Lemoine-Goumard, M; Lenain, J -P; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Marx, R; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Méhault, J; Meintjes, P J; Menzler, U; Meyer, M; Mitchell, A M W; Moderski, R; Mohamed, M; Morå, K; Moulin, E; Murach, T; de Naurois, M; Niemiec, J; Nolan, S J; Oakes, L; Odaka, H; Ohm, S; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Reichardt, I; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Rob, L; Romoli, C; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Salek, D; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spanier, F; Spengler, G; Spies, F; Stawarz, ?; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Tavernet, J -P; Tavernier, T; Taylor, A M; Terrier, R; Tluczykont, M; Trichard, C; Valerius, K; van Eldik, C; van Soelen, B; Vasileiadis, G; Veh, J; Venter, C; Viana, A; Vincent, P; Vink, J; Völk, H J; Volpe, F; Vorster, M; Vuillaume, T; Wagner, P; Wagner, R M; Ward, M; Weidinger, M; Weitzel, Q; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Yang, R; Zabalza, V; Zaborov, D; Zacharias, M; Zdziarski, A A; Zech, A; Zechlin, H -S

    2015-01-01T23:59:59.000Z

    Very high energy (VHE, $E>$100 GeV) $\\gamma$-ray flaring activity of the high-frequency peaked BL Lac object \\pg\\ has been detected by the \\hess\\ telescopes. The flux of the source increased by a factor of 3 during the nights of 2012 April 26 and 27 with respect to the archival measurements with hint of intra-night variability. No counterpart of this event has been detected in the \\fla\\ data. This pattern is consistent with VHE $\\gamma$ ray flaring being caused by the injection of ultrarelativistic particles, emitting $\\gamma$ rays at the highest energies. The dataset offers a unique opportunity to constrain the redshift of this source at \\bestz\\ using a novel method based on Bayesian statistics. The indication of intra-night variability is used to introduce a novel method to probe for a possible Lorentz Invariance Violation (LIV), and to set limits on the energy scale at which Quantum Gravity (QG) effects causing LIV may arise. For the subluminal case, the derived limits are $\\textrm{E}_{\\rm QG,1}>4.10\\times...

  10. Kalman Filtering in Correlated Losses Sachin Adlakha

    E-Print Network [OSTI]

    Adlakha, Sachin

    for such networks is the tracking and navigation of autonomous vehicles using sensor nodes. Such applications in presence of correlated losses using a Kalman Filter . This scenario arises in performing vehicle tracking Electro Mechanical Systems (MEMS) have fueled interest in research and development of a new class

  11. Standby and Off-Mode Energy Losses

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Standby and Off-Mode Energy Losses In New Appliances Measured in Shops #12;ISBN: 978 with the University of Coimbra. Its research interests include energyefficient technologies, renewable energies, and energy planning. Recent work includes the coordination of several European projects on market

  12. Loss and thermal noise in plasmonic waveguides

    SciTech Connect (OSTI)

    Syms, R. R. A., E-mail: r.syms@imperial.ac.uk; Solymar, L. [Optical and Semiconductor Devices Group, EEE Department, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2014-06-07T23:59:59.000Z

    Rytov's theory of thermally generated radiation is used to find the noise in two-dimensional passive guides based on an arbitrary distribution of lossy isotropic dielectric. To simplify calculations, the Maxwell curl equations are approximated using difference equations that also permit a transmission-line analogy, and material losses are assumed to be low enough for modal losses to be estimated using perturbation theory. It is shown that an effective medium representation of each mode is valid for both loss and noise and, hence, that a one-dimensional model can be used to estimate the best achievable noise factor when a given mode is used in a communications link. This model only requires knowledge of the real and imaginary parts of the modal dielectric constant. The former can be found by solving the lossless eigenvalue problem, while the latter can be estimated using perturbation theory. Because of their high loss, the theory is most relevant to plasmonic waveguides, and its application is demonstrated using single interface, slab, and slot guide examples. The best noise performance is offered by the long-range plasmon supported by the slab guide.

  13. Collisional parton energy loss in a finite size QCD medium revisited: Off mass-shell effects

    E-Print Network [OSTI]

    Alejandro Ayala; J. Magnin; Luis Manuel Montano; Eduardo Rojas

    2008-03-25T23:59:59.000Z

    We study the collisional energy loss mechanism for particles produced off mass-shell in a finite size QCD medium. The off mass-shell effects introduced are to consider particles produced in wave packets instead of plane waves and the length scale associated to an in-medium particles' life-time. We show that these effects reduce the energy loss as compared to the case when the particles are described as freely propagating from the source. The reduction of the energy loss is stronger as this scale becomes of the order or smaller than the medium size. We discuss possible consequences of the result on the description of the energy loss process in the parton recombination scenario.

  14. Endocortical bone loss in osteoporosis: the role of bone surface availability

    E-Print Network [OSTI]

    Buenzli, Pascal R; Clement, John G; Pivonka, Peter

    2012-01-01T23:59:59.000Z

    Age-related bone loss and postmenopausal osteoporosis are disorders of bone remodelling, in which less bone is reformed than resorbed. Yet, this dysregulation of bone remodelling does not occur equally in all bone regions. Loss of bone is more pronounced near the endocortex, leading to cortical wall thinning and medullary cavity expansion, a process sometimes referred to as "trabecularisation" or "cancellisation". Cortical wall thinning is of primary concern in osteoporosis due to the strong reduction in bone mechanical properties that it is associated with. In this paper, we examine the possibility that the nonuniformity of microscopic bone surface availability could explain the nonuniformity of bone loss in osteoporosis. We use a simple computational model of bone remodelling, in which microscopic bone surface availability influences bone turnover rate, to simulate the evolution of the bone volume fraction profile across the midshaft of a long bone. We find that bone loss is accelerated near the endocortica...

  15. Magnetically enhanced centrifugation for continuous biopharmaceutical processing

    E-Print Network [OSTI]

    Chen, Fei, Ph. D. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    Effective separation and purification of biopharmaceutical products from the media in which they are produced continues to be a challenging task. Such processes usually involve multiple steps and the overall product loss ...

  16. Solar activity can be surprisingly good for Last month, the sun went haywire. Almost every day for two weeks in early September, solar flares

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Solar activity can be surprisingly good for astronauts Last month, the sun went haywire. Almost every day for two weeks in early September, solar flares issued from a giant sunspot named "active region 798/808." X-rays ionized Earth's upper atmosphere. Solar protons peppered the Moon

  17. Multi-wavelength observations of 3C 279 during the extremely bright gamma-ray flare in 2014 March-April

    E-Print Network [OSTI]

    Paliya, Vaidehi S; Stalin, C S

    2015-01-01T23:59:59.000Z

    The well studied blazar 3C 279 underwent a giant $\\gamma$-ray outburst in 2014 March-April. The measured $\\gamma$-ray flux (1.21 $\\pm$ 0.10 $\\times$ 10$^{-5}$ ph cm$^{-2}$ s$^{-1}$ in 0.1-300 GeV energy range) is the highest detected from 3C 279 by Fermi Large Area Telescope. Hour scale $\\gamma$-ray flux variability are observed, with a flux doubling time as short as 1.19 $\\pm$ 0.36 hours detected during one flare. The $\\gamma$-ray spectrum is found to be curved at peak of the flare suggesting low probability of detecting very high energy (VHE; E $>$ 100 GeV) emission, which is further confirmed by the Very Energetic Radiation Imaging Telescope Array System observations. The $\\gamma$-ray flux increased by more than an order in comparison to low activity state and the flare consists of multiple sub-structures having fast rise and slow decay profile. The flux enhancement is seen in all the wavebands though at a lesser extent compared to $\\gamma$-rays. During the flare, a considerable amount of the kinetic jet p...

  18. Tuneable dielectric films having low electrical losses

    DOE Patents [OSTI]

    Dimos, Duane Brian (Albuquerque, NM); Schwartz, Robert William (Albuquerque, NM); Raymond, Mark Victor (Albuquerque, NM); Al-Shareef, Husam Niman (Boise, ID); Mueller, Carl (Lakewood, CO); Galt, David (Denver, CO)

    2000-01-01T23:59:59.000Z

    The present invention is directed to a method for forming dielectric thin films having substantially reduced electrical losses at microwave and millimeter wave frequencies relative to conventional dielectric thin films. The reduction in losses is realized by dramatically increasing the grain sizes of the dielectric films, thereby minimizing intergranular scattering of the microwave signal due to grain boundaries and point defects. The increase in grain size is realized by heating the film to a temperature at which the grains experience regrowth. The grain size of the films can be further increased by first depositing the films with an excess of one of the compoents, such that a highly mobile grain boundary phase is formed.

  19. Scannerless laser range imaging using loss modulation

    DOE Patents [OSTI]

    Sandusky, John V. (Albuquerque, NM)

    2011-08-09T23:59:59.000Z

    A scannerless 3-D imaging apparatus is disclosed which utilizes an amplitude modulated cw light source to illuminate a field of view containing a target of interest. Backscattered light from the target is passed through one or more loss modulators which are modulated at the same frequency as the light source, but with a phase delay .delta. which can be fixed or variable. The backscattered light is demodulated by the loss modulator and detected with a CCD, CMOS or focal plane array (FPA) detector to construct a 3-D image of the target. The scannerless 3-D imaging apparatus, which can operate in the eye-safe wavelength region 1.4-1.7 .mu.m and which can be constructed as a flash LADAR, has applications for vehicle collision avoidance, autonomous rendezvous and docking, robotic vision, industrial inspection and measurement, 3-D cameras, and facial recognition.

  20. Scannerless loss modulated flash color range imaging

    DOE Patents [OSTI]

    Sandusky, John V. (Albuquerque, NM); Pitts, Todd Alan (Rio Rancho, NM)

    2008-09-02T23:59:59.000Z

    Scannerless loss modulated flash color range imaging methods and apparatus are disclosed for producing three dimensional (3D) images of a target within a scene. Apparatus and methods according to the present invention comprise a light source providing at least three wavelengths (passbands) of illumination that are each loss modulated, phase delayed and simultaneously directed to illuminate the target. Phase delayed light backscattered from the target is spectrally filtered, demodulated and imaged by a planar detector array. Images of the intensity distributions for the selected wavelengths are obtained under modulated and unmodulated (dc) illumination of the target, and the information contained in the images combined to produce a 3D image of the target.

  1. Scannerless loss modulated flash color range imaging

    DOE Patents [OSTI]

    Sandusky, John V. (Albuquerque, NM); Pitts, Todd Alan (Rio Rancho, NM)

    2009-02-24T23:59:59.000Z

    Scannerless loss modulated flash color range imaging methods and apparatus are disclosed for producing three dimensional (3D) images of a target within a scene. Apparatus and methods according to the present invention comprise a light source providing at least three wavelengths (passbands) of illumination that are each loss modulated, phase delayed and simultaneously directed to illuminate the target. Phase delayed light backscattered from the target is spectrally filtered, demodulated and imaged by a planar detector array. Images of the intensity distributions for the selected wavelengths are obtained under modulated and unmodulated (dc) illumination of the target, and the information contained in the images combined to produce a 3D image of the target.

  2. Energy loss rate in disordered quantum well

    SciTech Connect (OSTI)

    Tripathi, P.; Ashraf, S. S. Z. [Centre of Excellence in Nanomaterials, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh-202002 (India); Hasan, S. T. [Physics Department, Faculty of Science, The M.S. University of Baroda, Vadodara-390002 (India); Sharma, A. C. [Physics Department, Sibli National College, Azamgarh-276128 (India)

    2014-04-24T23:59:59.000Z

    We report the effect of dynamically screened deformation potential on the electron energy loss rate in disordered semiconductor quantum well. Interaction of confined electrons with bulk acoustic phonons has been considered in the deformation coupling. The study concludes that the dynamically screened deformation potential coupling plays a significant role as it substantially affects the power dependency of electron relaxation on temperature and mean free path.

  3. Assessing Phosphorous Loss to Protect Surface Water

    E-Print Network [OSTI]

    Garcia, Raul

    2005-01-01T23:59:59.000Z

    Phosphorus LossStory by Raul L. Garcia The Texas State Soil and Water ConservationBoard (TSSWCB) in collaboration with the Department of Soil and Crop Sciences at Texas A&M University, Texas Cooperative Extension (TCE), Texas Water Resources... Institute (TWRI), and the U.S. Department of Agriculture's Natural Resource Conservation Service (NRCS), have developed a field validation of the Texas Phosphorus Index. This project, located near Bosque and Leon Rivers, began June 1, 2002, and ended...

  4. Recent Stirling engine loss - understanding results

    SciTech Connect (OSTI)

    Tew, R.C.; Thieme, L.G.; Dudenhoefer, J.E.

    1994-09-01T23:59:59.000Z

    For several years, the National Aeronautics and Space Administration and other US Government agencies have been funding experimental and analytical efforts to improve the understanding of Stirling thermodynamic losses. NASA`s objective is to improve Stirling engine design capability to support the development of new engines for space power. An overview of these efforts was last given at the 1988 IECEC. Recent results of this research are reviewed.

  5. Understanding Loss Mechanisms and Efficiency Improvement Options for HCCI Engines Using Detailed Exergy Analysis

    E-Print Network [OSTI]

    Saxena, Samveg

    2013-01-01T23:59:59.000Z

    Exergy Loss from Cylinder Gases Combustion Heat Loss Exhaustheptane and Natural Gas blends Combustion in HCCI Engines,”from Cylinder Gases (%) Loss Mechanisms Combustion Heat Loss

  6. The Flare-energy Distributions Generated by Kink-unstable Ensembles of Zero-net-current Coronal Loops

    E-Print Network [OSTI]

    Bareford, M R; Van der Linden, R A M

    2011-01-01T23:59:59.000Z

    It has been proposed that the million degree temperature of the corona is due to the combined effect of barely-detectable energy releases, so called nanoflares, that occur throughout the solar atmosphere. Alas, the nanoflare density and brightness implied by this hypothesis means that conclusive verification is beyond present observational abilities. Nevertheless, we investigate the plausibility of the nanoflare hypothesis by constructing a magnetohydrodynamic (MHD) model that can derive the energy of a nanoflare from the nature of an ideal kink instability. The set of energy-releasing instabilities is captured by an instability threshold for linear kink modes. Each point on the threshold is associated with a unique energy release and so we can predict a distribution of nanoflare energies. When the linear instability threshold is crossed, the instability enters a nonlinear phase as it is driven by current sheet reconnection. As the ensuing flare erupts and declines, the field transitions to a lower energy sta...

  7. Spectral Studies of Flaring FSRQs at GeV Energies Using Pass 8 Fermi-LAT Data

    E-Print Network [OSTI]

    Britto, Richard J G; Lott, Benoît

    2015-01-01T23:59:59.000Z

    Flat spectrum radio quasars (FSRQs) are bright active galactic nuclei surrounded by gas clouds within a UV-visible intense radiation field that form the so-called broad line region (BLR). These objects emit relativistic jets from a region close to the central supermassive black hole and through the BLR. The Fermi-Large Area Telescope (Fermi-LAT) is sensitive to gamma-ray photons from $\\sim$30 MeV to more than 300 GeV. We have performed spectral analysis of bright FSRQs in a 5.5 year (2008-2014) data sample collected by Fermi-LAT, using the new Pass 8 event selection and instrument response function. Also, our study of flaring episodes in a limited time range brings interesting results while compared to the full 5.5 year data samples.

  8. A Change in the Optical Polarization Associated with a Gamma-Ray Flare in the Blazar 3C 279

    SciTech Connect (OSTI)

    Abdo, A.A.

    2011-08-19T23:59:59.000Z

    It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma ({gamma})-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and {gamma}-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10{sup 5} gravitational radii.

  9. FLARE-ASSOCIATED TYPE III RADIO BURSTS AND DYNAMICS OF THE EUV JET FROM SDO/AIA AND RHESSI OBSERVATIONS

    SciTech Connect (OSTI)

    Chen Naihwa; Ip, Wing-Huen [Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China); Innes, Davina, E-mail: d949001@astro.ncu.edu.tw, E-mail: wingip@astro.ncu.edu.tw, E-mail: innes@mps.mpg.de [Max-Planck-Institut fuer Sonnensystemforschung, D-37191 Katlenburg-Lindau (Germany)

    2013-06-01T23:59:59.000Z

    We present a detailed description of the interrelation between the Type III radio bursts and energetic phenomena associated with the flare activities in active region AR11158 at 07:58 UT on 2011 February 15. The timing of the Type III radio burst measured by the radio wave experiment on Wind/WAVE and an array of ground-based radio telescopes coincided with an extreme-ultraviolet (EUV) jet and hard X-ray (HXR) emission observed by SDO/AIA and RHESSI, respectively. There is clear evidence that the EUV jet shares the same source region as the HXR emission. The temperature of the jet, as determined by multiwavelength measurements by Atmospheric Imaging Assembly, suggests that Type III emission is associated with hot, 7 MK, plasma at the jet's footpoint.

  10. Process oil manufacturing process

    SciTech Connect (OSTI)

    Corman, B.G.; Korbach, P.F.; Webber, K.M.

    1989-01-31T23:59:59.000Z

    A method is described for producing a naphthenic process oil having reduced sulfur, nitrogen and polynuclear aromatics contents from a naphthenic feed containing same and having an atmospheric boiling range of about 650/sup 0/ to about 1200/sup 0/F. comprising: A. passing the feed into a first hydrotreating stage having a hydrotreating catalyst therein, the stage maintained at a temperature of about 600/sup 0/ to about 750/sup 0/F. and at a hydrogen partial pressure of about 400 to about 1500 psig, to convert at least a portion of the sulfur to hydrogen sulfide and the nitrogen to ammonia; B. passing the hydrotreated feed from the first hydrotreating stage in an intermediate stripping stage wherein hydrogen sulfide, ammonia, or both is removed; C. passing the hydrotreated feed from the intermediate stage into a second hydrotreating stage having therein a hydrotreating catalyst selected from the group consisting of nickel-molybdenum, cobalt-molybdenum, nickel-tungsten and mixtures thereof, the second hydrotreating stage maintained at a temperature lower than that of the first hydrotreating stage and at a hydrogen partial pressure ranging between about 400 and about 1,500 psig; D. monitoring the polynuclear aromatics content, the degree of saturation, or both of the product exiting the second hydrotreating stage; and, E. adjusting the temperature in the second hydrotreating stage to keep the polynuclear aromatics content, the degree of saturation, or both below a limit suitable for process oil.

  11. Suzaku Detection of an Intense X-Ray Flare from an A-type Star HD161084

    E-Print Network [OSTI]

    Junichiro Miura; Masahiro Tsujimoto; Yohko Tsuboi; Yoshitomo Maeda; Yasuharu Sugawara; Katsuji Koyama; Shigeo Yamauchi

    2007-11-08T23:59:59.000Z

    We report a serendipitous detection of an intense X-ray flare from the Tycho reference source HD 161084 during a Suzaku observation of the Galactic Center region for 20 ks. The X-ray Imaging Spectrometer (XIS) recorded a flare from this A1-type dwarf or subgiant star with a flux of 1.4x10^{-12} erg s^{-1} cm^{-2} (0.5--10 keV) and a decay time scale of 0.5 hr. The spectrum is hard with a prominent Fe XXV K alpha emission line at 6.7 keV, which is explained by a 5 keV thin-thermal plasma model attenuated by a 1.4x10^{21} cm^{-2} extinction. The low extinction, which is consistent with the optical reddening, indicates that the source is a foreground star toward the Galactic Center region. Based on the spectroscopic parallax distance of 530 pc, the peak X-ray luminosity amounts to 1x10^{32} erg s^{-1} (0.5--10 keV). This is much larger than the X-ray luminosity of ordinary late-type main-sequence stars, and the X-ray emission is unattributable to a hidden late-type companion that comprises a wide binary system with the A-star. We discuss possible natures of HD 161084 and suggest that it is most likely an interacting binary with elevated magnetic activity in the companion such as the Algol-type system. The flux detected by Suzaku during the burst is 100 times larger than the quiescent level measured using the archived XMM-Newton and Chandra data. The large flux amplification makes this star a unique example among sources of this class.

  12. In Situ Electron Energy Loss Spectroscopy in Liquids

    E-Print Network [OSTI]

    Holtz, Megan E; Gao, Jie; Abruña, Héctor D; Muller, David A

    2012-01-01T23:59:59.000Z

    In situ scanning transmission electron microscopy (STEM) through liquids is a promising approach for exploring biological and materials processes. However, options for in situ chemical identification are limited: X-ray analysis is precluded because the holder shadows the detector, and electron energy loss spectroscopy (EELS) is degraded by multiple scattering events in thick layers. Here, we explore the limits of EELS for studying chemical reactions in their native environments in real time and on the nanometer scale. The determination of the local electron density, optical gap and thickness of the liquid layer by valence EELS is demonstrated for liquids. By comparing theoretical and experimental plasmon energies, we find that liquids appear to follow the free-electron model that has been previously established for solids. Signals at energies below the optical gap and plasmon energy of the liquid provide a high signal-to-background ratio as demonstrated for LiFePO4 in aqueous solution. The potential for using...

  13. Methane/nitrogen separation process

    DOE Patents [OSTI]

    Baker, R.W.; Lokhandwala, K.A.; Pinnau, I.; Segelke, S.

    1997-09-23T23:59:59.000Z

    A membrane separation process is described for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. The authors have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen. 11 figs.

  14. Methane/nitrogen separation process

    DOE Patents [OSTI]

    Baker, Richard W. (Palo Alto, CA); Lokhandwala, Kaaeid A. (Menlo Park, CA); Pinnau, Ingo (Palo Alto, CA); Segelke, Scott (Mountain View, CA)

    1997-01-01T23:59:59.000Z

    A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

  15. System Losses and Assessment Trade Study

    SciTech Connect (OSTI)

    David Shropshire; Steve Piet; Nick Soelberg; Robert Cherry; Roger Henry; David Meikrantz; Greg Teske; Eric Shaber; Candido Pereira

    2009-09-01T23:59:59.000Z

    This Advanced Fuel Cycle Initiative (AFCI) study has developed new analysis methods to examine old and new technology options toward the goal of improving fuel cycle systems. We have integrated participants and information from AFCI Systems Analysis, Transmutation Fuels, Separations, and Waste Form Campaigns in the Systems Losses and Assessment Trade Study. The initial objectives of this study were to 1) increase understanding of system interdependencies and thereby identify system trade-offs that may yield important insights, 2) define impacts of separations product purity on fuel manufacture and transmutation reactivity, 3) define impacts from transuranic (TRU) losses to waste, 4) identify the interrelationships involved in fuels and separations technology performance, and 5) identify system configuration adjustments with the greatest potential for influencing system losses. While bounding and analyzing this initial problem, we also identified significantly higher-level programmatic drivers with broad implications to the current fuel cycle research charter and the general issue of a DOE complex wide need for a comprehensive and integrated nuclear material management as addressed by the new DOE Order 410.2 titled “Management of Nuclear Materials”. The initial modeling effort developed in this study for a much smaller subset of material (i.e., commercial fuel) and a selected transmutation scheme (i.e., fast reactor recycling) is a necessary first step towards examining a broader set of nuclear material management options, dispositioning strategies and integrated waste management options including potential areas of research leverage. The primary outcome from this initial study has been an enhanced integration among Campaigns and associated insights and analysis methods. Opportunities for improved understanding between the groups abound. The above lanthanide-actinide example highlights the importance of evaluating options via integration across the Campaigns. Plans for Fiscal Year 2010 are being made in a coordinated fashion such that the knowledge gained from the research performed by the Campaigns can benefit on-going work of the study, and that improved understanding of the system relationships can be used to guide the specific research and development (R&D) activities within the Campaigns. In FY-10, the System Losses and Assessment Trade Study will carry-over activities from FY-09. We will continue to refine impurity and loss estimates and impurity limits on fuels by incorporating results from ongoing R&D. And we will begin work on an enhanced nuclear material management model to allow us to continue to improve our overall system understanding of the trade-offs between separations, fuel fabrication, waste forms, waste disposition, SNM losses, reactor performance, and proliferation resistance. In the future, we can also better understand how used fuel and other forms of remote-handled SNM can be better integrated into an overall nuclear material management program that will evolve for the DOE complex via Order 410.2 (DOE 2009).

  16. Recessed light fixtures: Infiltration energy loss

    SciTech Connect (OSTI)

    Bennett, S.M.; Perez-Blanco, H. (Pennsylvania State Univ., University Park, PA (United States))

    1994-06-01T23:59:59.000Z

    This article reports that a recent study revealed that fluorescent bulbs can reduce convective energy losses by 15--65% as compared to incandescent bulbs. Recessed light fixtures are commonly installed in offices and homes. However, a problem arises in homes when the fixtures are set in the ceiling such that the top of the light fixture is exposed to the unconditioned air in the attic. Because some air flow is necessary around the light to avoid overheating, the manufacturers do not make all the fixtures leak tight, only those that are rated for lower wattage bulbs. The need for cooling the fixture may conflict with some building efficiency codes.

  17. CHARACTERIZING LOSSES IN MICROSTRIP TRANSMISSION LINES Rashmi Pathak

    E-Print Network [OSTI]

    Timbie, Peter

    CHARACTERIZING LOSSES IN MICROSTRIP TRANSMISSION LINES by Rashmi Pathak A dissertation submitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Transmission Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Engineering) at the UNIVERSITY OF WISCONSIN­MADISON Summer 2005 #12;i Characterizing Losses in Transmission

  18. Draft 'Michigan Saves' Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample loan loss reserve agreement between a state or local government and a financial institution setting the terms and conditions of the loan loss reserve fund. Author: State of Michigan

  19. Characterizing Shading Losses on Partially Shaded PV Systems (Presentation)

    SciTech Connect (OSTI)

    Deline, C.

    2010-09-23T23:59:59.000Z

    Presentation on shaded PV power loss, practical issues with modeling shaded PV, and methods of implementing partially shaded PV modeling.

  20. On the origin and physics of Gamma Flares in Crab Nebula

    E-Print Network [OSTI]

    Machabeli, George; Shapakidze, David

    2015-01-01T23:59:59.000Z

    We consider parametric generation of electrostatic waves in the magnetosphere of the pulsar PSR0531. It is shown that in the framework of this mechanism it is possible to convert the pulsar rotational energy into the energy of Langmuir waves. The maximum growth rate is achieved in the "superluminal" area, where phase velocity of perturbations is exceeding the speed of light. Therefore electromagnetic waves do not damp on particles. Instead, they create plasmon condensate, which is carried out, outside of the pulsar magnetosphere and reaches the Crab nebula. It is shown, that the transfer of the energy of the plasmon condensate from the light cylinder to the active region of the nebula happens practically without losses. Unlike the plasma of the magnetosphere, the one of nebula contains ions, i.e., it may sustain modulation instability, which leads to the collapse of the Langmuir condensate. Langmuir wave collapse, in turn, leads to the acceleration of the distribution function particles. Furthermore, we consi...

  1. The Capacity Loss of Dense Constellations Tobias Koch

    E-Print Network [OSTI]

    high SNR, our results recover the power loss of 1.53dB for square signal constellations without-noise channels for suitably high signal- to-noise ratio. Our expression for the capacity loss recovers the power loss of 1.53dB for square signal constellations. I. INTRODUCTION As it is well known, the channel

  2. Advanced EL inspection with predictive estimation of module power loss

    E-Print Network [OSTI]

    Advanced EL inspection with predictive estimation of module power loss Ralph Schmidt (Dipl.-Ing) pi4_robotics GmbH Berlin #12;Agenda: - Introduction pi4 - The idea: Estimate power loss at an early stage in production - Investigation of single cells with defects - Estimation of Power loss for PV

  3. Cotton Insect Losses 1983 Compiled for National Cotton Council

    E-Print Network [OSTI]

    Ray, David

    Cotton Insect Losses 1983 Compiled for National Cotton Council Robert B. Head, Coordinator consultants and other personnel associated with cotton production. The Cotton Foundation provided funds their respective areas. Table 1 Alabama Cotton Insect Losses for 1983 Loss attributable to: Percent Bales Boll

  4. Cotton Insect Losses 1991 Compiled for National Cotton Council

    E-Print Network [OSTI]

    Ray, David

    Cotton Insect Losses 1991 Compiled for National Cotton Council Robert B. Head, Chairman Cooperative to have produced the greatest pest related losses in U. S. cotton in 1991. Aphid losses reported at 2. This is true for sweet potato whiteflies. These insects have been pests of cotton in California and Arizona

  5. Loss Factor of the PEP-II Rings

    SciTech Connect (OSTI)

    Novokhatski, A; Sullivan, M.; /SLAC

    2008-07-11T23:59:59.000Z

    An RF power balance method is used to measure the synchrotron radiation losses and the wake field losses. We present the history of the losses in the Low Energy Ring (LER) and the High Energy Ring (HER) during the last several runs of PEP-II.

  6. Processing Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Processing Science Related to the Electron Beam Melting Additive Manufacturing Process October 14 th , 2014 Ryan Dehoff Metal Additive Manufacturing Thrust Lead Manufacturing...

  7. Selection Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Selection Process Selection Process Fellowships will be awarded based on academic excellence, relevance of candidate's research to the laboratory mission in fundamental nuclear...

  8. Proposal Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Proposal Process Network R&D Overview Experimental Network Testbeds 100G SDN Testbed Testbed Description Testbed Results Current Testbed Research Proposal Process Terms and...

  9. Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992

    SciTech Connect (OSTI)

    Boden, T.A.; Marland, G. [Oak Ridge National Lab., TN (United States); Andres, R.J. [University of Alaska, Fairbanks, AK (United States). Inst. of Northern Engineering

    1995-12-01T23:59:59.000Z

    This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, provides estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.

  10. Particle-in-cell simulations of particle energization via shock drift acceleration from low Mach number quasi-perpendicular shocks in solar flares

    E-Print Network [OSTI]

    Park, Jaehong; Workman, Jared C; Blackman, Eric G

    2012-01-01T23:59:59.000Z

    Low Mach number, high beta fast mode shocks can occur in the magnetic reconnection outflows of solar flares. These shocks, which occur above flare loop tops, may provide the electron energization responsible for some of the observed hard X-rays and contemporaneous radio emission. Here we present new 2D particle-in-cell simulations of low Mach number/high beta quasi-perpendicular shocks. The simulations show that electrons above a certain energy threshold experience shock-drift-acceleration. The transition energy between the thermal and non-thermal spectrum and the spectral index from the simulations are consistent with some of the X-ray spectra from RHESSI in the energy regime, $E\\lesssim 40\\sim 100$ keV. Plasma instabilities associated with the shock structure such as the modified-two-stream and the electron whistler/mirror instabilities are examined and compared with the numerical solutions of the kinetic dispersion relations.

  11. Global warming, insurance losses and financial industry

    SciTech Connect (OSTI)

    Low, N.C. [UOB Life Assurance Limited, Singapore (Singapore)

    1996-12-31T23:59:59.000Z

    Global warming causes extremely bad weather in the near term. They have already caught the attention of the insurance industry, as they suffered massive losses in the last decade. Twenty-one out of the 25 largest catastrophes in the US, mainly in the form of hurricanes have occurred in the last decade. The insurance industry has reacted by taking the risk of global warming in decisions as to pricing and underwriting decisions. But they have yet to take a more active role in regulating the factors that contributes to global warming. How global warming can impact the financial industry and the modern economy is explored. Insurance and modern financial derivatives are key to the efficient functioning of the modern economy, without which the global economy can still function but will take a giant step backward. Any risk as global warming that causes economic surprises will hamper the efficient working of the financial market and the modern economy.

  12. Control of transformer losses in Canada

    SciTech Connect (OSTI)

    Wiegand, D.A. [Canadian Standards Association, Toronto, Ontario (Canada)

    1994-12-31T23:59:59.000Z

    A new standard issued by the Canadian Standards Association, CSA C802, imposes maximum losses on transformers 10 MVA and below. Included are Distribution Transformers, small Power Transformers, and Dry Types. Implementation will start though the publishing in mid 1994 of the Gazette by Ontario`s Ministry of Energy. The Gazette will call for conformance to C802 after a lead time of one year to eighteen months, depending on the type of transformer. Other provincial energy ministries have been awaiting this development and are expected to follow suit shortly thereafter. The federal department, Natural Resources Canada, is also attuned to these actions and is expected to issue supportive legislation which will control movement of transformers across provincial and national borders.

  13. LATERAL OFFSET OF THE CORONAL MASS EJECTIONS FROM THE X-FLARE OF 2006 DECEMBER 13 AND ITS TWO PRECURSOR ERUPTIONS

    SciTech Connect (OSTI)

    Sterling, Alphonse C.; Moore, Ronald L. [Space Science Office, VP62, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Harra, Louise K., E-mail: alphonse.sterling@nasa.gov, E-mail: ron.moore@nasa.gov, E-mail: lkh@mssl.ucl.ac.uk [UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2011-12-10T23:59:59.000Z

    Two GOES sub-C-class precursor eruptions occurred within {approx}10 hr prior to and from the same active region as the 2006 December 13 X4.3-class flare. Each eruption generated a coronal mass ejection (CME) with center laterally far offset ({approx}> 45 Degree-Sign ) from the co-produced bright flare. Explaining such CME-to-flare lateral offsets in terms of the standard model for solar eruptions has been controversial. Using Hinode/X-Ray Telescope (XRT) and EUV Imaging Spectrometer (EIS) data, and Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) and Michelson Doppler Imager (MDI) data, we find or infer the following. (1) The first precursor was a 'magnetic-arch-blowout' event, where an initial standard-model eruption of the active region's core field blew out a lobe on one side of the active region's field. (2) The second precursor began similarly, but the core-field eruption stalled in the side-lobe field, with the side-lobe field erupting {approx}1 hr later to make the CME either by finally being blown out or by destabilizing and undergoing a standard-model eruption. (3) The third eruption, the X-flare event, blew out side lobes on both sides of the active region and clearly displayed characteristics of the standard model. (4) The two precursors were offset due in part to the CME originating from a side-lobe coronal arcade that was offset from the active region's core. The main eruption (and to some extent probably the precursor eruptions) was offset primarily because it pushed against the field of the large sunspot as it escaped outward. (5) All three CMEs were plausibly produced by a suitable version of the standard model.

  14. The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf

    E-Print Network [OSTI]

    Segura, Antígona; Meadows, Victoria; Kasting, James; Hawley, Suzanne

    2010-01-01T23:59:59.000Z

    Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwarf, AD Leonis (AD Leo), simulating the effects from both UV radiation and protons on the atmospheric chemistry of a hypothetical, Earth-like planet located within its habitable zone. Based on observations of solar proton events and the Neupert effect we estimated a proton flux associated with the flare of $5.9\\times 10^{8}$ protons cm$^{-2}$ sr$^{-1}$ s$^{-1}$ for particles with energies >10 MeV. Then we calculated the abundance of nitrogen oxides produced by the flare by scaling the production of these compounds during a large solar proton event called the "Carrington event". The simulations were performed using a 1-D photochemical model coupled to a 1-D radiative/co...

  15. Waste Heat Reduction and Recovery for Improving Furnace Efficiency, Productivity and Emissions Performance: A BestPractices Process Heating Technical Brief

    SciTech Connect (OSTI)

    Not Available

    2004-11-01T23:59:59.000Z

    This technical brief is a guide to help plant operators reduce waste heat losses associated with process heating equipment.

  16. Controlling internal barrier in low loss BaTiO3 supercapacitors U-C. Chung, C. Elissalde, S. Mornet and M. Maglione

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Controlling internal barrier in low loss BaTiO3 supercapacitors U-C. Chung, C. Elissalde, S Supercapacitor behavior has been reported in a number of oxides including reduced BaTiO3 ferroelectric ceramics to process bulk composites having supercapacitor features with low dielectric losses and temperature

  17. Process Modeling for Process Improvement A Process Conformance Approach

    E-Print Network [OSTI]

    Process Modeling for Process Improvement - A Process Conformance Approach Sigurd Thunem September processes. In order to improve these processes, knowledge about them is necessary. To support process improve- ment the organization should collect process data, transform process data into knowledge

  18. STELLAR CORONAE, SOLAR FLARES: A DETAILED COMPARISON OF {sigma} GEM, HR 1099, AND THE SUN IN HIGH-RESOLUTION X-RAYS

    SciTech Connect (OSTI)

    Huenemoerder, David P. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Phillips, Kenneth J. H. [Visiting Scientist, Space Research Center, Polish Academy of Sciences, 51-622, Kopernika 11, Wroclaw (Poland); Sylwester, Janusz; Sylwester, Barbara, E-mail: dph@space.mit.edu, E-mail: kennethjhphillips@yahoo.com, E-mail: js@cbk.pan.wroc.pl, E-mail: bs@cbk.pan.wroc.pl [Space Research Center, Polish Academy of Sciences, 51-622, Kopernika 11, Wroclaw (Poland)

    2013-05-10T23:59:59.000Z

    The Chandra High Energy Transmission Grating Spectrometer (HETG) spectra of the coronally active binary stars {sigma} Gem and HR 1099 are among the highest fluence observations for such systems taken at high spectral resolution in X-rays with this instrument. This allows us to compare their properties in detail to solar flare spectra obtained with the Russian CORONAS-F spacecraft's RESIK instrument at similar resolution in an overlapping bandpass. Here we emphasize the detailed comparisons of the 3.3-6.1 A region (including emission from highly ionized S, Si, Ar, and K) from solar flare spectra to the corresponding {sigma} Gem and HR 1099 spectra. We also model the larger wavelength range of the HETG, from 1.7 to 25 A - having emission lines from Fe, Ca, Ar, Si, Al, Mg, Ne, O, and N-to determine coronal temperatures and abundances. {sigma} Gem is a single-lined coronally active long-period binary which has a very hot corona. HR 1099 is a similar, but shorter period, double-lined system. With very deep HETG exposures we can even study emission from some of the weaker species, such as K, Na, and Al, which are important since they have the lowest first ionization potentials, a parameter well known to be correlated with elemental fractionation in the solar corona. The solar flare temperatures reach Almost-Equal-To 20 MK, comparable to the {sigma} Gem and HR 1099 coronae. During the Chandra exposures, {sigma} Gem was slowly decaying from a flare and its spectrum is well characterized by a collisional ionization equilibrium plasma with a broad temperature distribution ranging from 2 to 60 MK, peaking near 25 MK, but with substantial emission from 50 MK plasma. We have detected K XVIII and Na XI emission which allow us to set limits on their abundances. HR 1099 was also quite variable in X-rays, also in a flare state, but had no detectable K XVIII. These measurements provide new comparisons of solar and stellar coronal abundances, especially at the lowest first ionization potential (FIP) values. The low FIP elements do not show enhancement in the stellar coronae as they do in the Sun, except perhaps for K in {sigma} Gem. While {sigma} Gem and HR 1099 differ in their emission measure distributions, they have very similar elemental abundances.

  19. NEUTRINO ANALYSIS OF THE 2010 SEPTEMBER CRAB NEBULA FLARE AND TIME-INTEGRATED CONSTRAINTS ON NEUTRINO EMISSION FROM THE CRAB USING ICECUBE

    SciTech Connect (OSTI)

    Abbasi, R.; Aguilar, J. A.; Andeen, K.; Baker, M. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Abdou, Y. [Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium); Abu-Zayyad, T. [Department of Physics, University of Wisconsin, River Falls, WI 54022 (United States); Adams, J. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Ahlers, M. [Department of Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Altmann, D. [III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen (Germany); Auffenberg, J.; Becker, K.-H. [Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany); Bai, X. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Barwick, S. W. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Bay, R. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Bazo Alba, J. L.; Benabderrahmane, M. L. [DESY, D-15735 Zeuthen (Germany); Beattie, K. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Beatty, J. J. [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Bechet, S. [Science Faculty CP230, Universite Libre de Bruxelles, B-1050 Brussels (Belgium); Becker, J. K. [Fakultaet fuer Physik and Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); and others

    2012-01-20T23:59:59.000Z

    We present the results of a search for high-energy muon neutrinos with the IceCube detector in coincidence with the Crab Nebula flare reported on 2010 September by various experiments. Due to the unusual flaring state of the otherwise steady source we performed a prompt analysis of the 79-string configuration data to search for neutrinos that might be emitted along with the observed {gamma}-rays. We performed two different and complementary data selections of neutrino events in the time window of 10 days around the flare. One event selection is optimized for discovery of E{sup -2}{sub {nu}} neutrino spectrum typical of first-order Fermi acceleration. A similar event selection has also been applied to the 40-string data to derive the time-integrated limits to the neutrino emission from the Crab. The other event selection was optimized for discovery of neutrino spectra with softer spectral index and TeV energy cutoffs as observed for various Galactic sources in {gamma}-rays. The 90% confidence level (CL) best upper limits on the Crab flux during the 10 day flare are 4.73 Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} TeV{sup -1} for an E{sup -2}{sub {nu}} neutrino spectrum and 2.50 Multiplication-Sign 10{sup -10} cm{sup -2} s{sup -1} TeV{sup -1} for a softer neutrino spectra of E{sup -2.7}{sub {nu}}, as indicated by Fermi measurements during the flare. In this paper, we also illustrate the impact of the time-integrated limit on the Crab neutrino steady emission. The limit obtained using 375.5 days of the 40-string configuration is compared to existing models of neutrino production from the Crab and its impact on astrophysical parameters is discussed. The most optimistic predictions of some models are already rejected by the IceCube neutrino telescope with more than 90% CL.

  20. An investigation of simplified loss formula evaluation of total and incremental power system losses

    E-Print Network [OSTI]

    Malinowski, James Henry

    1962-01-01T23:59:59.000Z

    Program ~ a o o ~ o a o o o o e a o o 11 Incremental Transmission Loss Calculation . . . . . . o 13 The Transmission System ~ a ~ o o ~ ~ o o o o o o 14 IVa RESULTS e ~ o a ~ ~ a a ~ e a o a ~ e ~ o a o o o IQ V SUMMARY a o o o a ~ o ~ a o 0 o o o ~ 0..., 1 X II tf g tf ff tf lt 4 0o9 50/ System Load ? Per Cent of Peak 1o06 f 1. 05 0 Xo1. 04 0 e 5 1, 03 1. 02 Ir 5 F. 1o01 4 tI 1o0 III II 0. 99 5 FIGURE IVa Simplified Loss Formula Evaluation of Pen- alty Faotor ? Bus 1 All...

  1. Cool horizons lead to information loss

    E-Print Network [OSTI]

    Borun D. Chowdhury

    2013-07-29T23:59:59.000Z

    There are two evidences for information loss during black hole evaporation: (i) a pure state evolves to a mixed state and (ii) the map from the initial state to final state is non-invertible. Any proposed resolution of the information paradox must address both these issues. The firewall argument focuses only on the first and this leads to order one deviations from the Unruh vacuum for maximally entangled black holes. The nature of the argument does not extend to black holes in pure states. It was shown by Avery, Puhm and the author that requiring the initial state to final state map to be invertible mandates structure at the horizon even for pure states. The proof works if black holes can be formed in generic states and in this paper we show that this is indeed the case. We also demonstrate how models proposed by Susskind, Papadodimas et al. and Maldacena et al. end up making the initial to final state map non-invertible and thus make the horizon "cool" at the cost of unitarity.

  2. Detonation propagation in a high loss configuration

    SciTech Connect (OSTI)

    Jackson, Scott I [Los Alamos National Laboratory; Shepherd, Joseph E [CALTECH

    2009-01-01T23:59:59.000Z

    This work presents an experimental study of detonation wave propagation in tubes with inner diameters (ID) comparable to the mixture cell size. Propane-oxygen mixtures were used in two test section tubes with inner diameters of 1.27 mm and 6.35 mm. For both test sections, the initial pressure of stoichiometric mixtures was varied to determine the effect on detonation propagation. For the 6.35 mm tube, the equivalence ratio {phi} (where the mixture was {phi} C{sub 3}H{sub 8} + 50{sub 2}) was also varied. Detonations were found to propagate in mixtures with cell sizes as large as five times the diameter of the tube. However, under these conditions, significant losses were observed, resulting in wave propagation velocities as slow as 40% of the CJ velocity U{sub CJ}. A review of relevant literature is presented, followed by experimental details and data. Observed velocity deficits are predicted using models that account for boundary layer growth inside detonation waves.

  3. Photolytic Processes

    Broader source: Energy.gov [DOE]

    Photolytic processes use the energy in sunlight to separate water into hydrogen and oxygen. These processes are in the very early stages of research but offer long-term potential for sustainable...

  4. Moreton Waves and EIT Waves Related to the Flare Events of June 3, 2012 and July 6, 2012

    E-Print Network [OSTI]

    Admiranto, A G; Yus'an, U; Puspitaningrum, E

    2015-01-01T23:59:59.000Z

    We present geometrical and kinematical analysis of Moreton waves and EIT waves observed on June 3, 2012 and Moreton waves observed on July 6, 2012. The Moreton waves were recorded in H$\\alpha$ images of Global Oscillation Network Group (GONG) archive and EIT waves obtained from SDO/AIA observations, especially in 193 nm channel. The observed wave of June 3 has angular span of about $70^{\\circ}$ with a broad wave front associated to NOAA active region 11496. It was found that the speed of the wave that started propagating at 17.53 UT is between 950 to 1500 km/s. Related to this wave occurrence, there was solar type II and III radio bursts. The speed of the EIT in this respect about 247 km/sec. On the other hand, the wave of July 6 may be associated to X1.1 class flare that occurred at 23.01 UT around the 11514 active region. From the kinematical analysis, the wave propagated with the initial velocity of about 1180 km/s which is in agreement with coronal shock velocity derived from type II radio burst observati...

  5. Bright X-ray flares in XRF 050406 and GRB 050502B provide evidence for extended central engine activity

    E-Print Network [OSTI]

    Burrows, D N; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'Brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S D; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-01-01T23:59:59.000Z

    Gamma-ray bursts (GRBs) are the most powerful explosions since the Big Bang, with typical energies around 10**51 ergs. Long GRBs (duration > 2 s) are thought to signal the creation of black holes, most likely by collapse of massive stars. The detected signals from the resulting highly relativistic fireball consist of prompt gamma-ray emission (from internal shocks in the fireball) lasting for several seconds to minutes, followed by afterglow emission (from external shocks as the fireball encounters surrounding material) covering a broad range of frequencies from radio through X-rays. Because of the time needed to determine the GRB position, most afterglow measurements have been made hours after the burst, and little is known about the characteristics of afterglows in the minutes following a burst, when the afterglow emission is actively responding to inhomogeneities in both the fireball and the circumburst environment. Here we report our discovery of two bright X-ray flares peaking a few minutes after the bur...

  6. Time delays in quasi-periodic pulsations observed during the X2.2 solar flare on 2011 February 15

    E-Print Network [OSTI]

    Dolla, L; Seaton, D B; Van Doorsselaere, T; Dominique, M; Berghmans, D; Cabanas, C; De Groof, A; Schmutz, W; Verdini, A; West, M J; Zender, J; Zhukov, A N

    2012-01-01T23:59:59.000Z

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on time scale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the Extreme Ultra-Violet (EUV) channels of the Euv SpectroPhotometer (ESP) onboard the Solar Dynamic Observatory (SDO). The Zirconium and Aluminum filter channels of the Large Yield Radiometer (LYRA) onboard the Project for On-Board Autonomy (PROBA2) satellite and the SXR channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite (GOES), where the channel at 1-8 {\\AA} leads the 0.5-4 {\\AA} channel by several seconds. The time lags between the first and last channels is up to 9 ...

  7. Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

    E-Print Network [OSTI]

    Ackermann, M; Ballet, J; Barbiellini, G; Bastieri, D; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Charles, E; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cutini, S; D'Ammando, F; de Palma, F; Dermer, C D; Silva, E do Couto e; Drell, P S; Drlica-Wagner, A; Dubois, R; Favuzzi, C; Fegan, S J; Ferrara, E C; Focke, W B; Fortin, P; Fuhrmann, L; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Guiriec, S; Hadasch, D; Hayashida, M; Hughes, R E; Itoh, R; Johannesson, G; Johnson, A S; Katagiri, H; Kataoka, J; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Lee, S -H; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Nishino, S; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ozaki, M; Paneque, D; Panetta, J H; Pelassa, V; Pesce-Rollins, M; Pierbattista, M; Piron, F; Pivato, G; Porter, T A; Raino, S; Rando, R; Rastawicki, D; Razzano, M; Readhead, A; Reimer, A; Reimer, O; Reyes, L C; Richards, J L; Sbarra, C; Sgro, C; Siskind, E J; Spandre, G; Spinelli, P; Szostek, A; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Winer, B L; Wood, K S; Yang, Z; Zimmer, S; Moderski, R; Nalewajko, K; Sikora, M; Villata, M; Raiteri, C M; Aller, H D; Aller, M F; Arkharov, A A; Benitez, E; Berdyugin, A; Blinov, D A; Boettcher, M; Calle, O J A Bravo; Buemi, C S; Carosati, D; Chen, W P; Diltz, C; Di Paola, A; Dolci, M; Efimova, N V; Forn\\', E; Gurwell, M A; Heidt, J; Hiriart, D; Jordan, B; Kimeridze, G; Konstantinova, T S; Kopatskaya, E N; Koptelova, E; Kurtanidze, O M; Lahteenmaki, A; Larionova, E G; Larionova, L V; Larionov, V M; Leto, P; Lindfors, E; Lin, H C; Morozova, D A; Nikolashvili, M G; Nilsson, K; Oksman, M; Roustazadeh, P; Sievers, A; Sigua, L A; Sillanpaa, A; Takahashi, T; Takalo, L O; Tornikoski, M; Trigilio, C; Troitsky, I S; Umana, G; Angelakis, E; Krichbaum, T P; Nestoras, I; Riquelme, D; Krips, M; Trippe, S; Arai, A; Kawabata, K S; Sakimoto, K; Sasada, M; Sato, S; Uemura, M; Yamanaka, M; Yoshida, M; Belloni, T; Tagliaferri, G; Bonning, E W; Isler, J; Urry, C M; Hoversten, E; Falcone, A; Pagani, C; Stroh, M

    2012-01-01T23:59:59.000Z

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to {\\gamma} -ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP- WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the {\\gamma} -ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of th...

  8. Importance of Biologically Active Aurora-like Ultraviolet Emission: Stochastic Irradiation of Earth and Mars by Flares and Explosions

    E-Print Network [OSTI]

    David S. Smith; John Scalo; J. Craig Wheeler

    2003-07-30T23:59:59.000Z

    (Abridged) We show that sizeable fractions of incident ionizing radiation from stochastic astrophysical sources can be redistributed to biologically and chemically important UV wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption, with energies low enough to excite atmospheric molecules and atoms, resulting in a rich aurora-like spectrum. We calculate the fraction of energy redistributed into biologically and chemically important wavelength regions for spectra characteristic of stellar flares and supernovae using a Monte-Carlo transport code written for this problem and then estimate the fraction of this energy that is transmitted from the atmospheric altitudes of redistribution to the surface for a few illustrative cases. Redistributed fractions are found to be of order 1%, even in the presence of an ozone shield. This result implies that planetary organisms will be subject to mutationally significant, if intermittent, fluences of UV-B and harder radiation even in the presence of a narrow-band UV shield like ozone. We also calculate the surficial transmitted fraction of ionizing radiation and redistributed ultraviolet radiation for two illustrative evolving Mars atmospheres whose initial surface pressures were 1 bar. Our results suggest that coding organisms on planets orbiting low-mass stars (and on the early Earth) may evolve very differently than on contemporary Earth, with diversity and evolutionary rate controlled by a stochastically varying mutation rate and frequent hypermutation episodes.

  9. Hydrocarbon Processing`s petrochemical processes `97

    SciTech Connect (OSTI)

    NONE

    1997-03-01T23:59:59.000Z

    The paper compiles information on numerous petrochemical processes, describing the application, the process, yields, economics, commercial plants, references, and licensor. Petrochemicals which are synthesized include: alkylbenzene, methylamines, ammonia, benzene, bisphenol-A, BTX aromatics, butadiene, butanediol, butyraldehyde, caprolactam, cumene, dimethyl terephthalate, ethanolamines, ethylbenzene, ethylene, ethylene glycols, ethylene oxide, formaldehyde, maleic anhydride, methanol, olefins, paraxylene, phenol, phthalic anhydride, polycaproamide, polyethylene, polyethylene terephthalate, polypropylene, PVC, styrene, terephthalic acid, urea, vinyl chloride, and xylene isomers.

  10. 4, 50455074, 2004 Arctic ozone loss in

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , Germany 4 Central Aerological Observatory (CAO), Moscow, Russia 5 Institute of Atmospheric Sciences and Climate (ISAC), Italian National Research Council, Bologna, Italy 6 Alfred Wegener Institute, Potsdam changes to the CTM have improved the model's ability to reproduce polar chemical and dynamical processes.5

  11. Efficient gas-separation process to upgrade dilute methane stream for use as fuel

    DOE Patents [OSTI]

    Wijmans, Johannes G. (Menlo Park, CA); Merkel, Timothy C. (Menlo Park, CA); Lin, Haiqing (Mountain View, CA); Thompson, Scott (Brecksville, OH); Daniels, Ramin (San Jose, CA)

    2012-03-06T23:59:59.000Z

    A membrane-based gas separation process for treating gas streams that contain methane in low concentrations. The invention involves flowing the stream to be treated across the feed side of a membrane and flowing a sweep gas stream, usually air, across the permeate side. Carbon dioxide permeates the membrane preferentially and is picked up in the sweep air stream on the permeate side; oxygen permeates in the other direction and is picked up in the methane-containing stream. The resulting residue stream is enriched in methane as well as oxygen and has an EMC value enabling it to be either flared or combusted by mixing with ordinary air.

  12. Charm production and energy loss at the LHC with ALICE

    E-Print Network [OSTI]

    Andrea Dainese; for the ALICE Collaboration

    2004-09-29T23:59:59.000Z

    The latest results on the ALICE performance for production and in-medium QCD energy loss measurements of charm particles at the LHC are presented.

  13. Structuring Loan Loss Reserve Funds for Clean Energy Finance...

    Broader source: Energy.gov (indexed) [DOE]

    Loan loss reserve funds ("LRF"): * provide partial risk coverage to motivate commercial FIs to offer EERE finance products, pioneer new products, broaden access to finance,...

  14. Polarization Losses under Accelerated Stress Test Using Multiwalled...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Accelerated Stress Test Using Multiwalled Carbon Nanotube Supported Pt Catalyst in PEM Fuel Cells. Polarization Losses under Accelerated Stress Test Using Multiwalled Carbon...

  15. ac losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    23 24 25 Next Page Last Page Topic Index 1 Transport AC loss in high temperature superconducting coils University of Cambridge - Dspace Summary: 's electromagnetic properties and...

  16. Microsoft Word - Completion of an Evalution of Impact of Loss...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Completion of an Evaluation of the Impact of the Loss of Two Hydrogen and Methane Monitoring Sampling Lines Dear Mr. Bearzi: As required under Permit Condition...

  17. Global Volcano Proportional Economic Loss Risk Distribution Projection: Robinson

    E-Print Network [OSTI]

    Columbia University

    Global Volcano Proportional Economic Loss Risk Distribution Projection: Robinson Like Total Deichmann, Arthur L. Lerner-Lam, and Margaret Arnold. 2005. Natural Disaster Hotspots: A Global Risk

  18. Draft Michigan SAVES Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample LRF agreement between a grantee and an financial institution setting the terms and conditions of the loan loss reserve fund.

  19. Estimated Business Interruptions Losses of the Deepwater Horizon Oil Spill.

    E-Print Network [OSTI]

    Vargas, Vanessa

    2011-01-01T23:59:59.000Z

    ??A generalized framework of Economic Analysis of natural and man-made disasters is applied to the estimation of business interruption losses associated with an oil spill.… (more)

  20. Basic TRUEX process for Rocky Flats Plant

    SciTech Connect (OSTI)

    Leonard, R.A.; Chamberlain, D.B.; Dow, J.A.; Farley, S.E.; Nunez, L.; Regalbuto, M.C.; Vandegrift, G.F.

    1994-08-01T23:59:59.000Z

    The Generic TRUEX Model was used to develop a TRUEX process flowsheet for recovering the transuranics (Pu, Am) from a nitrate waste stream at Rocky Flats Plant. The process was designed so that it is relatively insensitive to changes in process feed concentrations and flow rates. Related issues are considered, including solvent losses, feed analysis requirements, safety, and interaction with an evaporator system for nitric acid recycle.

  1. Proposal Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Testbed Results Current Testbed Research Proposal Process Terms and Conditions Dark Fiber Testbed Performance (perfSONAR) Software & Tools Development Partnerships...

  2. Legal Access to Geographic Information: Measuring Losses or Developing Responses?

    E-Print Network [OSTI]

    Onsrud, Harlan J.

    are obvious and a focus on measuring losses in such situations seems misplaced when energies might be better and measurements those in power positions are often able to divert attention and energy away from the goals digital data environments. As a result, widespread loss of access to information and works of knowledge

  3. Modelling and Computation of AC Fields and Losses in

    E-Print Network [OSTI]

    Sóbester, András

    electricity but inherently has energy losses associated with (joule) heating. Fault current limiters would be installed in transmission and distribution systems, especially for electric utilities and large energy users. High-Tc superconductors experience energy loss when exposed to time-varying magnetic fields or carrying

  4. Linear-optics manipulations of photon-loss codes

    E-Print Network [OSTI]

    Konrad Banaszek; Wojciech Wasilewski

    2007-02-09T23:59:59.000Z

    We discuss codes for protecting logical qubits carried by optical fields from the effects of amplitude damping, i.e. linear photon loss. We demonstrate that the correctability condition for one-photon loss imposes limitations on the range of manipulations than can be implemented with passive linear-optics networks.

  5. MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS

    E-Print Network [OSTI]

    Mi, Chunting "Chris"

    the performance of the machine. This paper presents the modeling and analysis of eddy current loss in surfaceMODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS IN PERMANENT MAGNET MACHINES ¤ XIAOFENG DING Electrical Engineering Department, Northwestern Polytechnical University, 127 Youyi Xilu #352

  6. The efficiency of voluntary incentive policies for preventing biodiversity loss

    E-Print Network [OSTI]

    Weiblen, George D

    Biodiversity Conservation Land use Spatial modeling A B S T R A C T Habitat loss is a primary cause of loss of biodiversity but conserving habitat for species presents challenges. Land parcels differ in their ability conservation objectives. This topic is important not just for biodiversity conservation but for any effort

  7. Global Volcano Total Economic Loss Risk Distribution Projection: Robinson

    E-Print Network [OSTI]

    Columbia University

    Global Volcano Total Economic Loss Risk Distribution Projection: Robinson Total Economic Loss International Bank for Reconstruction and Development/The World Bank and Columbia University. Volcano Total, Arthur L. Lerner-Lam, and Margaret Arnold. 2005. Natural Disaster Hotspots: A Global Risk Analysis

  8. Electron energy-loss spectrum of nanowires G. F. Bertsch

    E-Print Network [OSTI]

    Bertsch George F.

    Electron energy-loss spectrum of nanowires G. F. Bertsch Institute of Nuclear Theory and Department, Cornell University, Ithaca, New York 14853 Received 8 May 1998 The electronic properties of nanoscale-size fibers can be studied by electron energy-loss spectroscopy with electron beams that pass near the fiber

  9. average energy losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    average energy losses First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Comparing energy loss...

  10. additional energy losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    additional energy losses First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Comparing energy loss...

  11. Chemical Biology Chemical Screening for Hair Cell Loss and Protection

    E-Print Network [OSTI]

    Rubel, Edwin

    Chemical Biology Chemical Screening for Hair Cell Loss and Protection in the Zebrafish Lateral Line Rubel,1,2 and David W. Raible1,4 Abstract In humans, most hearing loss results from death of hair cells, the mechanosensory receptors of the inner ear. Two goals of current hearing research are to protect hair cells from

  12. Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3

    E-Print Network [OSTI]

    Nebot Del Busto, E; Branger, E; Holzer, E B; Doebert, S; Lillestol, R L; Welsch, C P

    2013-01-01T23:59:59.000Z

    The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the bea...

  13. Mechanical Loss in Tantala/Silica Dielectric Mirror Coatings

    E-Print Network [OSTI]

    Steven D. Penn; Peter H. Sneddon; Helena Armandula; Joseph C. Betzwieser; Gianpietro Cagnoli; Jordan Camp; D. R. M. Crooks; Martin M. Fejer; Andri M. Gretarsson; Gregory M. Harry; Jim Hough; Scott E. Kittelberger; Michael J. Mortonson; Roger Route; Sheila Rowan; Christophoros C. Vassiliou

    2003-02-24T23:59:59.000Z

    Current interferometric gravitational wave detectors use test masses with mirror coatings formed from multiple layers of dielectric materials, most commonly alternating layers of SiO2 (silica) and Ta2O5 (tantala). However, mechanical loss in the Ta2O5/SiO2 coatings may limit the design sensitivity for advanced detectors. We have investigated sources of mechanical loss in the Ta2O5/SiO2 coatings, including loss associated with the coating-substrate interface, with the coating-layer interfaces, and with the bulk material. Our results indicate that the loss is associated with the bulk coating materials and that the loss of Ta2O5 is substantially larger than that of SiO2.

  14. Fuel Saving Ideas for Metal and Ceramic Processing

    E-Print Network [OSTI]

    Reed, R. J.

    1982-01-01T23:59:59.000Z

    An easy method is presented for analyzing sources of heat loss from industrial processing furnaces, kilns, and ovens; and thus for recognizing opportunities for fuel saving. This will relate to melting, heat treating and hot forming of metals...

  15. In Situ Energy Loss Instruments for Insulation Economy and Process Control

    E-Print Network [OSTI]

    Hauser, R. L.; McKeever, R. B.; Stull, D. P.

    and follow changes off ambient weather conditions for indoor, outdoor, buried and downhole applications. A variation of this instrument can be placed on columns under insulation to act as control sensor for adiabatic operation....

  16. The effect of stress cracked and broken corn kernels on alkaline processing losses

    E-Print Network [OSTI]

    Jackson, David Scott

    1986-01-01T23:59:59.000Z

    used and the final product desirecL Then the cooked corn and water mixture is, &equently, pumped to a soaking tank for a 8-15 br steep, Other commercial operations utilize large cooking tanks which, after cooking, serve as steeping tanks. After...-samples of Pioneer 3780 (P3780) were also preparezL The first sub- sample was dried in a continuous elevator drying system at 46' C and steeped in a bin for 6 hr, then cooled with ambient temperature air. The second Pioneer 3780 sub- sample was bin (batch) dried...

  17. Process and apparatus for reducing the loss of hydrogen from Stirling engines

    SciTech Connect (OSTI)

    Alger, D.L.

    1987-03-24T23:59:59.000Z

    A Stirling engine assembly is described which defines a working gas volume therein, the Stirling engine assembly comprising: a working gas reservoir for storing a working gas at a pressure greater than pressure of the working gas in the working volume of the Stirling engine; a trap cell operatively connected between an outlet of the reservoir and the Stirling engine working volume. The trap cell includes an enclosure having porous windows at either end thereof and a sorbent with an affinity for water vapor therein, such that water vapor adsorbed on the sorbent diffuses into the hydrogen passing from the reservoir into the working engine; a compressor means for drawing working gas from the Stirling engine working volume, through the trap cell and pumping the working gas into the hydrogen reservoir. The sorbent in the trap cell at the reduced pressure caused by the compressor adsorbs water vapor from the working gas such that substantially dry working gas is pumped by the compressor into the reservoir. The working gas is doped with water vapor by the tank cell as it passes into the Stirling engine and is dried by the trap cell as it is removed from the working engine for storage in the reservoir to prevent condensation of water vapor in the reservoir.

  18. Investigating late stage biopharmaceutical product loss using novel analytical and process technology

    E-Print Network [OSTI]

    Hunnicutt, Leigh Anne

    2008-01-01T23:59:59.000Z

    The biopharmaceutical industry uses recombinant protein technologies to provide novel therapeutics to patients around the world. These technologies have presented exciting opportunities for breakthrough medical treatments ...

  19. TOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER THE THIN LINE BETWEEN GAIN AND LOSS

    E-Print Network [OSTI]

    Kik, Pieter

    and waveguide. If the pump laser could somehow be eliminated from this scheme, the fabrication of low-cost SiTOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER ­ THE THIN LINE BETWEEN GAIN AND LOSS-doped SiO2, a composite material that can potentially be fabricated using a VLSI compatible process

  20. The uncertainties due to quark energy loss on determining nuclear sea quark distribution from nuclear Drell-Yan data

    E-Print Network [OSTI]

    C. G. Duan; N. Liu; G. L. Li

    2008-11-05T23:59:59.000Z

    By means of two different parametrizations of quark energy loss and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order phenomenological analysis is performed on the nuclear Drell-Yan differential cross section ratios as a function of the quark momentum fraction in the beam proton and target nuclei for E772 experimental data. It is shown that there is the quark energy loss effect in nuclear Drell-Yan process apart from the nuclear effects on the parton distribution as in deep inelastic scattering. The uncertainties due to quark energy loss effect is quantified on determining nuclear sea quark distribution by using nuclear Drell-Yan data. It is found that the quark energy loss effect on nuclear Drell-Yan cross section ratios make greater with the increase of quark momentum fraction in the target nuclei. The uncertainties from quark energy loss become bigger as the nucleus A come to be heavier. The Drell-Yan data on proton incident middle and heavy nuclei versus deuterium would result in an overestimate for nuclear modifications on sea quark distribution functions with neglecting the quark energy loss. Our results are hoped to provide good directional information on the magnitude and form of nuclear modifications on sea quark distribution functions by means of the nuclear Drell-Yan experimental data.

  1. Loss of Fine Particle Ammonium from Denuded Nylon Filters

    SciTech Connect (OSTI)

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    2006-08-01T23:59:59.000Z

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH4NO3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, Illinois (February 2003), San Gorgonio, California (April 2003 and July 2004), Grand Canyon National Park, Arizona (May, 2003), Brigantine, New Jersey (November 2003), and Great Smoky Mountains National Park (NP), Tennessee (July–August 2004). Samples were collected over 24-hr periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, Illinois to 28% in San Gorgonio, California in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(--III) (particulate NH4+ plus gaseous NH3) present as gaseous NH3. The amount of ammonium lost at most sites could be explained by the amount of NH4NO3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH4NO3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  2. U-GAS process

    SciTech Connect (OSTI)

    Schora, F.C.; Patel, J.G.

    1982-01-01T23:59:59.000Z

    The Institute of Gas Technology (IGT) has developed an advanced coal gasification process. The U-GAS process has been extensively tested in a pilot plant to firmly establish process feasibility and provide a large data base for scale-up and design of the first commercial plant. The U-GAS process is considered to be one of the more flexible, efficient, and economical coal gasification technologies developed in the US during the last decade. The U-GAS technology is presently available for licensing from GDC, Inc., a wholly-owned subsidiary of IGT. The U-GAS process accomplishes four important functions in a single-stage, fluidized-bed gasifier: It decakes coal, devolatilizes coal, gasifies coal, and agglomerates and separates ash from char. Simultaneously with coal gasification, the ash is agglomerated into spherical particles and separated from the bed. Part of the fluidizing gas enters the gasifier through a sloping grid. The remaining gas flows upward at a high velocity through the ash agglomerating device and forms a hot zone within the fluidized bed. High-ash-content particles agglomerate under these conditions and grow into larger and heavier particles. Agglomerates grow in size until they can be selectively separated and discharged from the bed into water-filled ash hoppers where they are withdrawn as a slurry. In this manner, the fluidized bed achieves the same low level of carbon losses in the discharge ash generally associated with the ash-slagging type of gasifier. Coal fines elutriated from the fluidized bed are collected in two external cyclones. Fines from the first cyclone are returned to the bed and fines from the second cyclone are returned to the ash agglomerating zone, where they are gasified, and the ash agglomerated with bed ash. The raw product gas is virtually free of tar and oils, thus simplifying ensuing heat recovery and purification steps.

  3. Macdonald processes

    E-Print Network [OSTI]

    Borodin, Alexei

    Macdonald processes are probability measures on sequences of partitions defined in terms of nonnegative specializations of the Macdonald symmetric functions and two Macdonald parameters q,t ? [0,1). We prove several results ...

  4. Impacts of the Venezuelan Crude Oil Production Loss

    Reports and Publications (EIA)

    2003-01-01T23:59:59.000Z

    This assessment of the Venezuelan petroleum loss examines two areas. The first part of the analysis focuses on the impact of the loss of Venezuelan crude production on crude oil supply for U.S. refiners who normally run a significant fraction of Venezuelan crude oil. The second part of the analysis looks at the impact of the Venezuelan production loss on crude markets in general, with particular emphasis on crude oil imports, refinery crude oil throughput levels, stock levels, and the changes in price differences between light and heavy crude oils.

  5. Heavy ion beam loss mechanisms at an electron-ion collider

    E-Print Network [OSTI]

    Spencer R. Klein

    2014-09-18T23:59:59.000Z

    There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy-nuclei. We calculate the cross-sections for two important processes that will affect accelerator and detector operations: bound-free pair production, and Coulomb excitation of the nuclei. Both of these reactions have large cross-sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times $10^{32}/$cm$^2$/s.

  6. Ceramic tube seals cut heat loss, achieve six month payback

    SciTech Connect (OSTI)

    Not Available

    1985-11-01T23:59:59.000Z

    The methane reformer at the Celanese Chemical Company's Bishop, TX plant operates at approximately 1900/sup 0/F. The reformer has 32 tubes (9'' diameter) that pass through the firebox. Openings around the tubes measure 11'' in diameter to accommodate horizontal and vertical thermal expansion and movement as well as to facilitate tube removal. The gaps around the tubes permitted cool air to be drawn into the firebox (caused by slight negative pressure) and also allowed radiant heat to escape causing the reformer to operate at a lower than desired level of thermal efficiency. Celanese contracted to retrofit the old rigid firebrick roof in the methane reformer with a 10'' thick ceramic fiber module lining. The gaps around the tubes were sealed by using a special tube seal made from Nextel woven ceramic fiber fabric, a 1984 CHEMICAL PROCESSING Vaaler Award winner (Mid-November 1984, p.52). The Nextel fabric used in this application is a heat resistant textile that has a continuous use temperature of 2200/sup 0/F - well above the 1900/sup 0/F operating temperature of the reformer. The tube seals have been working exactly as intended, verified by observation through inspection ports. Temperatures in the penthouse area above the roof dropped from 240/sup 0/F to 150/sup 0/F. The reduction in heat losses has been attributed to the elimination of the gaps around each tube by the seals and to the improved K-factor of the ceramic module lining. The tube seals have paid for themselves within six months of installation. At that time, the seal boots were inspected and showed no signs of wear. With these results, the improved efficiency of the methane reformer promises to yield additional economic benefits.

  7. Cladding embrittlement during postulated loss-of-coolant accidents.

    SciTech Connect (OSTI)

    Billone, M.; Yan, Y.; Burtseva, T.; Daum, R.; Nuclear Engineering Division

    2008-07-31T23:59:59.000Z

    The effect of fuel burnup on the embrittlement of various cladding alloys was examined with laboratory tests conducted under conditions relevant to loss-of-coolant accidents (LOCAs). The cladding materials tested were Zircaloy-4, Zircaloy-2, ZIRLO, M5, and E110. Tests were performed with specimens sectioned from as-fabricated cladding, from prehydrided (surrogate for high-burnup) cladding, and from high-burnup fuel rods which had been irradiated in commercial reactors. The tests were designed to determine for each cladding material the ductile-to-brittle transition as a function of steam oxidation temperature, weight gain due to oxidation, hydrogen content, pre-transient cladding thickness, and pre-transient corrosion-layer thickness. For short, defueled cladding specimens oxidized at 1000-1200 C, ring compression tests were performed to determine post-quench ductility at {le} 135 C. The effect of breakaway oxidation on embrittlement was also examined for short specimens oxidized at 800-1000 C. Among other findings, embrittlement was found to be sensitive to fabrication processes--especially surface finish--but insensitive to alloy constituents for these dilute zirconium alloys used as cladding materials. It was also demonstrated that burnup effects on embrittlement are largely due to hydrogen that is absorbed in the cladding during normal operation. Some tests were also performed with longer, fueled-and-pressurized cladding segments subjected to LOCA-relevant heating and cooling rates. Recommendations are given for types of tests that would identify LOCA conditions under which embrittlement would occur.

  8. Geologic controls influencing CO2 loss from a leaking well.

    SciTech Connect (OSTI)

    Hopkins, Polly L.; Martinez, Mario J.; McKenna, Sean Andrew; Klise, Katherine A.

    2010-12-01T23:59:59.000Z

    Injection of CO2 into formations containing brine is proposed as a long-term sequestration solution. A significant obstacle to sequestration performance is the presence of existing wells providing a transport pathway out of the sequestration formation. To understand how heterogeneity impacts the leakage rate, we employ two dimensional models of the CO2 injection process into a sandstone aquifer with shale inclusions to examine the parameters controlling release through an existing well. This scenario is modeled as a constant-rate injection of super-critical CO2 into the existing formation where buoyancy effects, relative permeabilities, and capillary pressures are employed. Three geologic controls are considered: stratigraphic dip angle, shale inclusion size and shale fraction. In this study, we examine the impact of heterogeneity on the amount and timing of CO2 released through a leaky well. Sensitivity analysis is performed to classify how various geologic controls influence CO2 loss. A 'Design of Experiments' approach is used to identify the most important parameters and combinations of parameters to control CO2 migration while making efficient use of a limited number of computations. Results are used to construct a low-dimensional description of the transport scenario. The goal of this exploration is to develop a small set of parametric descriptors that can be generalized to similar scenarios. Results of this work will allow for estimation of the amount of CO2 that will be lost for a given scenario prior to commencing injection. Additionally, two-dimensional and three-dimensional simulations are compared to quantify the influence that surrounding geologic media has on the CO2 leakage rate.

  9. Physical processes shaping GRB X-ray afterglow lightcurves: theoretical implications from the Swift XRT observations

    E-Print Network [OSTI]

    Bing Zhang; Y. Z. Fan; Jaroslaw Dyks; Shiho Kobayashi; Peter Meszaros; David N. Burrows; John A. Nousek; Neil Gehrels

    2005-12-20T23:59:59.000Z

    (Abridged) The Swift X-Ray Telescope (XRT) reveals some interesting features of early X-ray afterglows, including a distinct rapidly decaying component preceding the conventional afterglow component in many sources, a shallow decay component before the more ``normal'' decay component observed in a good fraction of GRBs (e.g. GRB 050128, GRB 050315, GRB 050319, and GRB 050401), and X-ray flares in nearly half of the afterglows (e.g. GRB 050406, GRB 050502B, GRB 050607, and GRB 050724). In this paper, we systematically analyze the possible physical processes that shape the properties of the early X-ray afterglow lightcurves, and use the data to constrain various models. We suggest that the steep decay component is consistent with the tail emission of the prompt gamma-ray bursts and/or of the X-ray flares. This provides clear evidence that the prompt emission and afterglow emission are two distinct components, supporting the internal origin of the GRB prompt emission. The shallow decay segment observed in a group of GRBs suggests that the forward shock keeps being refreshed for some time. This might be caused either by a long-lived central engine, or by a power law distribution of the shell Lorentz factors, or else by the deceleration of a Poynting flux dominated flow. X-ray flares suggest that the GRB central engine is still active after the prompt gamma-ray emission is over, but with a reduced activity at later times. In some cases, the central engine activity even extends days after the burst trigger. Analyses of early X-ray afterglow data reveal that GRBs are indeed highly relativistic events. Early afterglow data of many bursts, starting from the beginning of the XRT observations, are consistent with the afterglow emission from an interstellar medium (ISM) environment.

  10. The effects of cosmic rays and solar flares on the IRAC detectors: the first two years of in-flight operation

    E-Print Network [OSTI]

    Joseph L. Hora; Brian M. Patten; Giovanni G. Fazio; William J. Glaccum

    2006-07-26T23:59:59.000Z

    The Infrared Array Camera (IRAC) is a four-channel camera on the Spitzer Space Telescope, one of three focal plane science instruments. IRAC uses two pairs of 256x256 pixel InSb and Si:As IBC detectors to provide simultaneous imaging at 3.6, 4.5, 5.8, and 8 microns. IRAC experiences a flux of cosmic rays and solar protons that produce transient effects in science images from each of the arrays, with 4-6 pixels per second being affected during each integration. During extreme solar flares, IRAC experiences a much higher rate of transients which affects the science data quality. We present cosmic ray rates and observed detector characteristics for IRAC during the first two years of science operation, and rates observed in a period of elevated solar proton flux during an intense solar flare in January 2005. We show the changes to the IRAC detectors observed since launch, and assess their impacts to the science data quality.

  11. Search for Lorentz Invariance breaking with a likelihood fit of the PKS 2155-304 flare data taken on MJD 53944

    E-Print Network [OSTI]

    HESS Collaboration; A. Abramowski; F. Acero; F. Aharonian; A. G. Akhperjanian; G. Anton; A. Barnacka; U. Barres de Almeida; A. R. Bazer-Bachi; Y. Becherini; J. Becker; B. Behera; K. Bernlöhr; A. Bochow; C. Boisson; J. Bolmont; P. Bordas; V. Borrel; J. Brucker; F. Brun; P. Brun; T. Bulik; I. Büsching; R. Bühler; S. Carrigan; S. Casanova; M. Cerruti; P. M. Chadwick; A. Charbonnier; R. C. G. Chaves; A. Cheesebrough; L. -M. Chounet; A. C. Clapson; G. Coignet; J. Conrad; M. Dalton; M. K. Daniel; I. D. Davids; B. Degrange; C. Deil; H. J. Dickinson; A. Djannati-Ataï; W. Domainko; L. O'C. Drury; F. Dubois; G. Dubus; J. Dyks; M. Dyrda; K. Egberts; P. Eger; P. Espigat; L. Fallon; C. Farnier; S. Fegan; F. Feinstein; M. V. Fernandes; A. Fiasson; A. Frster; G. Fontaine; M. Füßling; Y. A. Gallant; H. Gast; L. Gérard; D. Gerbig; B. Giebels; J. F. Glicenstein; B. Glück; P. Goret; D. Göring; J. D. Hague; D. Hampf; M. Hauser; S. Heinz; G. Heinzelmann; G. Henri; G. Hermann; J. A. Hinton; A. Hoffmann; W. Hofmann; P. Hofverberg; D. Horns; A. Jacholkowska; O. C. de Jager; C. Jahn; M. Jamrozy; I. Jung; M. A. Kastendieck; K. Katarzy?ski; U. Katz; S. Kaufmann; D. Keogh; M. Kerschhaggl; D. Khangulyan; B. Khélifi; D. Klochkov; W. Klu?niak; T. Kneiske; Nu. Komin; K. Kosack; R. Kossakowski; H. Laffon; G. Lamanna; D. Lennarz; T. Lohse; A. Lopatin; C. -C. Lu; V. Marandon; A. Marcowith; J. Masbou; D. Maurin; N. Maxted; T. J. L. McComb; M. C. Medina; J. Méhault; R. Moderski; E. Moulin; C. L. Naumann; M. Naumann-Godo; M. de Naurois; D. Nedbal; D. Nekrassov; N. Nguyen; B. Nicholas; J. Niemiec; S. J. Nolan; S. Ohm; J-F. Olive; E. de Oña Wilhelmi; B. Opitz; M. Ostrowski; M. Panter; M. Paz Arribas; G. Pedaletti1; G. Pelletier; P. -O. Petrucci; S. Pita; G. Pühlhofer; M. Punch; A. Quirrenbach; M. Raue; S. M. Rayner; A. Reimer; O. Reimer; M. Renaud; R. de los Reyes; F. Rieger; J. Ripken; L. Rob; S. Rosier-Lees; G. Rowell; B. Rudak; C. B. Rulten; J. Ruppel; F. Ryde; V. Sahakian; A. Santangelo; R. Schlickeiser; F. M. Schöck; A. Schönwald; U. Schwanke; S. Schwarzburg; S. Schwemmer; A. Shalchi; M. Sikora; J. L. Skilton; H. Sol; G. Spengler; ?. Stawarz; R. Steenkamp; C. Stegmann; F. Stinzing; I. Sushch; A. Szostek; J. -P. Tavernet; R. Terrier; O. Tibolla; M. Tluczykont; K. Valerius; C. van Eldik; G. Vasileiadis; C. Venter; J. P. Vialle; A. Viana; P. Vincent; M. Vivier; H. J. Völk; F. Volpe; S. Vorobiov; M. Vorster; S. J. Wagner; M. Ward; A. Wierzcholska; A. Zajczyk; A. A. Zdziarski; A. Zech; H. -S. Zechlin

    2011-02-02T23:59:59.000Z

    Several models of Quantum Gravity predict Lorentz Symmetry breaking at energy scales approaching the Planck scale (10^{19} GeV). With present photon data from the observations of distant astrophysical sources, it is possible to constrain the Lorentz Symmetry breaking linear term in the standard photon dispersion relations. Gamma-ray Bursts (GRB) and flaring Active Galactic Nuclei (AGN) are complementary to each other for this purpose, since they are observed at different distances in different energy ranges and with different levels of variability. Following a previous publication of the High Energy Stereoscopic System (H.E.S.S.) collaboration, a more sensitive event-by-event method consisting of a likelihood fit is applied to PKS 2155-304 flare data of MJD 53944 (July 28, 2006) as used in the previous publication. The previous limit on the linear term is improved by a factor of ~3 up to M^{l}_{QG} > 2.1x10^{18} GeV and is currently the best result obtained with blazars. The sensitivity to the quadratic term is lower and provides a limit of M^{q}_{QG} > 6.4x10^10 GeV, which is the best value obtained so far with an AGN and similar to the best limits obtained with GRB.

  12. Process Engineering Thermodynamics 424304 E (4 sp)

    E-Print Network [OSTI]

    Zevenhoven, Ron

    otherwise. 111. An oxygen plant processes 10 kmol/hour ambient air (21%-vol O2, 79%-vol N2). The oxygen of the products to ambient conditions. The exergy efficiency of the first reaction can be calculated using: Exergy of electricity in + Exergy of reactants = Exergy of products + Losses Note that for electric energy driven

  13. Macdonald processes

    E-Print Network [OSTI]

    Alexei Borodin; Ivan Corwin

    2013-01-06T23:59:59.000Z

    Macdonald processes are probability measures on sequences of partitions defined in terms of nonnegative specializations of the Macdonald symmetric functions and two Macdonald parameters q,t in [0,1). We prove several results about these processes, which include the following. (1) We explicitly evaluate expectations of a rich family of observables for these processes. (2) In the case t=0, we find a Fredholm determinant formula for a q-Laplace transform of the distribution of the last part of the Macdonald-random partition. (3) We introduce Markov dynamics that preserve the class of Macdonald processes and lead to new "integrable" 2d and 1d interacting particle systems. (4) In a large time limit transition, and as q goes to 1, the particles of these systems crystallize on a lattice, and fluctuations around the lattice converge to O'Connell's Whittaker process that describe semi-discrete Brownian directed polymers. (5) This yields a Fredholm determinant for the Laplace transform of the polymer partition function, and taking its asymptotics we prove KPZ universality for the polymer (free energy fluctuation exponent 1/3 and Tracy-Widom GUE limit law). (6) Under intermediate disorder scaling, we recover the Laplace transform of the solution of the KPZ equation with narrow wedge initial data. (7) We provide contour integral formulas for a wide array of polymer moments. (8) This results in a new ansatz for solving quantum many body systems such as the delta Bose gas.

  14. apical support loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    bags. We instead consider the problem of predicting instance labels while learning from data labeled only at the bag level. We propose Rank-Loss Support Instance Machines, which...

  15. acute interneuron loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    sets for previously unseen bags. We instead consider the problem of predicting instance labels while learning from data labeled only at the bag level. We propose Rank-Loss...

  16. Control of cooling losses at high pulverized coal injection rates

    SciTech Connect (OSTI)

    Bonte, L.; Nieuwerburgh, H. Van [Sidmar N.V., Gent (Belgium)

    1996-12-31T23:59:59.000Z

    One of the problems which is encountered by many blast furnace operators is the appropriate control of the cooling losses of the blast furnace. This problem has been aggravated by the introduction of pulverized coal injection. Even with equal burden and coke composition, both Sidmar furnaces behave differently with respect to the cooling losses. This phenomenon is possibly attributable to the different profile and cooling circuitry of the furnaces. Among other parameters the angles of bosh and stack may favor the formation of scabs or not. Some operators experience a decrease of their cooling losses, other operators have problems to limit their cooling losses to an acceptable level. As a result, different operating practices exist with respect to the burden distribution. The increase of the ore to coke ratio with pulverized coal injection suggests that the coke and sinter quality has to be monitored very carefully in order to avoid permeability problems.

  17. Correlation Of Surface Heat Loss And Total Energy Production...

    Open Energy Info (EERE)

    discharge). The conductive loss at or near the surface (shallow heat flow) is a primary signature and indication of the strength of a geothermal system. Using a database of...

  18. Return channel loss reduction in multi-stage centrifugal compressors

    E-Print Network [OSTI]

    Aubry, Anne-Raphaëlle

    2012-01-01T23:59:59.000Z

    This thesis presents concepts for improving the performance of return channels in multi-stage centrifugal compressors. Geometries have been developed to reduce both separation and viscous losses. A number of different ...

  19. Habitat loss and the structure of plantanimal mutualistic networks

    E-Print Network [OSTI]

    Fortuna, Miguel A.

    LETTER Habitat loss and the structure of plant­animal mutualistic networks Miguel A. Fortuna Sevilla, Spain *Correspondence: E-mail: fortuna@ebd.csic.es Abstract Recent papers have described

  20. Optimizing hysteretic power loss of magnetic ferrite nanoparticles

    E-Print Network [OSTI]

    Chen, Ritchie

    2013-01-01T23:59:59.000Z

    This thesis seeks to correlate hysteretic power loss of tertiary ferrite nanoparticles in alternating magnetic fields to trends predicted by physical models. By employing integration of hysteresis loops simulated from ...

  1. appendix gap losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    kicker performance and its effect on the beam losses will be described. Kourbanis, I; Biggs, J; Brown, B; Capista, D; Jensen, C C; Krafczyk, G E; Morris, D K; Scott, D; Seiya, K;...

  2. ChitChat : making video chat robust to packet loss

    E-Print Network [OSTI]

    Wang, Jue, 1986-

    2010-01-01T23:59:59.000Z

    Video chat is increasingly popular among Internet users (e.g. Skype, Windows Live Messenger, Google Talk). Often, however, chatting sessions suffer from packet loss, which causes video outage and poor quality. Existing ...

  3. ChitChat: Making Video Chat Robust to Packet Loss

    E-Print Network [OSTI]

    Wang, Jue

    2010-07-05T23:59:59.000Z

    Video chat is increasingly popular among Internet users. Often, however, chatting sessions suffer from packet loss, which causes video outage and poor quality. Existing solutions however are unsatisfying. Retransmissions ...

  4. Agricultural science students' perceptions and knowledge of hearing loss

    E-Print Network [OSTI]

    Slaydon, Sunny Leigh

    2009-05-15T23:59:59.000Z

    knowledge level of hearing loss and hearing impairment, and its causes, and participants attitudes towards wearing hearing protection. The study design is descriptive and correlational with data collected using a written questionnaire with a controlled...

  5. Compression effects on pressure loss in flexible HVAC ducts

    E-Print Network [OSTI]

    Abushakra, Bass; Walker, Iain S.; Sherman, Max H.

    2002-01-01T23:59:59.000Z

    to Determine Flow Resistance of HVAC Air Ducts and Fittings.Pressure Loss in Flexible HVAC Ducts Bass Abushakra, Ph.D.to Determine Flow Resistance of HVAC Air Ducts and Fittings.

  6. Motion based seismic design and loss estimation of diagrid structures

    E-Print Network [OSTI]

    Liptack, Robert J. (Robert Jeffrey)

    2013-01-01T23:59:59.000Z

    Diagrids are becoming an increasingly popular structural system in high rise design and construction. Little research has been performed on the seismic performance of Diagrids and how it integrates with seismic loss ...

  7. Loan Loss Reserve Funds and Other Credit Enhancements | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    used by state and local governments to provide partial risk coverage to lenders-meaning that the reserve will cover a prespecified amount of loan losses. For example, an LLR...

  8. Mode conversation losses in overmolded millimeter wave transmission lines

    E-Print Network [OSTI]

    Tax, David S. (David Samuel)

    2008-01-01T23:59:59.000Z

    Millimeter wave transmission lines are integral components for many important applications like nuclear fusion and NMR spectroscopy. In low loss corrugated transmission lines propagating the HE,1 mode with a high waveguide ...

  9. Loan Loss Reserves: Lessons from the Field (Text Version)

    Broader source: Energy.gov [DOE]

    Merrian Fuller: Hi, and welcome to the Department of Energy's webinar on using loan-loss reserves report financing programs. My name is Marian Fuller, I work with Lawrence Berkeley National...

  10. Effect of thermalized charm on heavy quark energy loss

    E-Print Network [OSTI]

    Souvik Priyam Adhya; Mahatsab Mandal; Sreemoyee Sarkar; Pradip K. Roy; Sukalyan Chattopadhyay

    2014-08-28T23:59:59.000Z

    The recent experimental results on the flow of $J/\\psi$ at LHC show that ample amount of charm quarks is present in the quark gluon plasma and probably they are thermalized. In the current study we investigate the effect of thermalized charm quarks on the heavy quark energy loss to leading order in the QCD coupling constant. It is seen that the energy loss of charm quark increases considerably due to the inclusion of thermal charm quarks. Running coupling has also been implemented to study heavy quark energy loss and we find substantial increase in the heavy quark energy loss due to heavy-heavy scattering at higher temperature to be realized at LHC energies.

  11. Loss-Resilient Proactive Data Transmission in Wireless Sensor Networks

    E-Print Network [OSTI]

    Xu, Jianliang

    environments. Moreover, sensor nodes are con- strained by energy, computation power and storage. Existing to the destination without loss. However, existing reliable transmission techniques either are too costly forecast, structural condition assessment) require reliable data communications, such that a target

  12. Estimate steam-turbine losses to justify maintenance funds

    SciTech Connect (OSTI)

    Not Available

    1982-05-01T23:59:59.000Z

    A procedure to estimate steam-turbine losses is described. The estimates are based on analytical calculations and field inspections of turbines with known performance deterioration resulting from their environment, not their construction. They are, therefore, applicable to many types of steam turbines. Common causes of deterioration are the following: solid particle erosion, deposits, increased clearances, and peening or damage from foreign material. Performance losses due to these factors are analyzed. An example of application is given.

  13. Beam Loss Monitors in the NSLS Storage Rings

    SciTech Connect (OSTI)

    Kramer,S.L.; Fedurin, M.

    2009-05-04T23:59:59.000Z

    Beam loss monitors (BLM) have been used for more than two decades in the VUV ring at the NSLS. These have proved useful for optimizing injection and operation of the ring. Recently similar monitors have been installed in the X-ray ring and are being used to better understand injection, as well as operation of the ring. These units have been compared with the Bergoz BLMs, which have been mostly useful for understanding operating beam losses.

  14. Polarization energy loss in hot viscous quark-gluon plasma

    E-Print Network [OSTI]

    Bing-Feng Jiang; Defu Hou; Jia-Rong Li

    2014-05-19T23:59:59.000Z

    The gluon polarization tensor for the quark-gluon plasma with shear viscosity is derived with the viscous chromohydrodynamics. The longitudinal and transverse dielectric functions are evaluated from the gluon polarization tensor, through which the polarization energy loss suffered by a fast quark traveling through the viscous quark-gluon plasma is investigated. The numerical analysis indicates that shear viscosity significantly reduces the polarization energy loss.

  15. Experimental study of head loss and filtration for LOCA debris

    SciTech Connect (OSTI)

    Rao, D.V.; Souto, F.J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)

    1996-02-01T23:59:59.000Z

    A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON{trademark} fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors.

  16. Understanding ion cyclotron harmonic fast wave heating losses in the scrape off layer of tokamak plasmas

    SciTech Connect (OSTI)

    Bertelli, N [PPPL; Jaeger, E F; Hosea, J C; Phillips, C K; Berry, L; Bonoli, P T; Gerhardt, S P [PPPL; Green, D; LeBlanc, B [PPPL; Perkins, R J; Ryan, P M; Taylor, G; Valeo, E J; Wilso, J R; Wright, J C

    2014-07-01T23:59:59.000Z

    Fast waves at harmonics of the ion cyclotron frequency, which have been used successfully on National Spherical Torus Experiment (NSTX), will also play an important role in ITER and are a promising candidate for the Fusion Nuclear Science Facility (FNSF) designs based on spherical torus (ST). Experimental studies of high harmonic fast waves (HHFW) heating on the NSTX have demonstrated that substantial HHFW power loss occurs along the open field lines in the scrape-off layer (SOL), but the mechanism behind the loss is not yet understood. The full wave RF code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain, is applied to specific NSTX discharges in order to predict the effects and possible causes of this power loss. In the studies discussed here, a collisional damping parameter has been implemented in AORSA as a proxy to represent the real, and most likely nonlinear, damping processes. A prediction for the NSTX Upgrade (NSTX-U) experiment, that will begin operation next year, is also presented, indicating a favorable condition for the experiment due to a wider evanescent region in edge density.*Research supported by the U.S. DOE under Contract No. DE-AC02-09CH11466 with Princeton University.

  17. The extraction of nuclear sea quark distribution and energy loss effect in Drell-Yan experiment

    E-Print Network [OSTI]

    Chun-Gui Duan; Na Liu; Zhan-Yuan Yan

    2006-09-06T23:59:59.000Z

    The next-to-leading order and leading order analysis are performed on the differential cross section ratio from Drell-Yan process. It is found that the effect of next-to-leading order corrections can be negligible on the differential cross section ratios as a function of the quark momentum fraction in the beam proton and the target nuclei for the current Fermilab and future lower beam proton energy. The nuclear Drell-Yan reaction is an ideal tool to study the energy loss of the fast quark moving through cold nuclei. In the leading order analysis, the theoretical results with quark energy loss are in good agreement with the Fermilab E866 experimental data on the Drell-Yan differential cross section ratios as a function of the momentum fraction of the target parton. It is shown that the quark energy loss effect has significant impact on the Drell-Yan differential cross section ratios. The nuclear Drell-Yan experiment at current Fermilab and future lower energy proton beam can not provide us with more information on the nuclear sea quark distribution.

  18. Purification process

    SciTech Connect (OSTI)

    Marshall, A.

    1981-02-17T23:59:59.000Z

    A process for the removal of hydrogen sulphide from gases or liquid hydrocarbons, comprises contacting the gas or liquid hydrocarbon with an aqueous alkaline solution, preferably having a pH value of 8 to 10, comprising (A) an anthraquinone disulphonic acid or a water-soluble sulphonamide thereof (B) a compound of a metal which can exist in at least two valency states and (C) a sequestering agent.

  19. Hydropyrolysis process

    DOE Patents [OSTI]

    Ullman, Alan Z. (Northridge, CA); Silverman, Jacob (Woodland Hills, CA); Friedman, Joseph (Huntington Beach, CA)

    1986-01-01T23:59:59.000Z

    An improved process for producing a methane-enriched gas wherein a hydrogen-deficient carbonaceous material is treated with a hydrogen-containing pyrolysis gas at an elevated temperature and pressure to produce a product gas mixture including methane, carbon monoxide and hydrogen. The improvement comprises passing the product gas mixture sequentially through a water-gas shift reaction zone and a gas separation zone to provide separate gas streams of methane and of a recycle gas comprising hydrogen, carbon monoxide and methane for recycle to the process. A controlled amount of steam also is provided which when combined with the recycle gas provides a pyrolysis gas for treatment of additional hydrogen-deficient carbonaceous material. The amount of steam used and the conditions within the water-gas shift reaction zone and gas separation zone are controlled to obtain a steady-state composition of pyrolysis gas which will comprise hydrogen as the principal constituent and a minor amount of carbon monoxide, steam and methane so that no external source of hydrogen is needed to supply the hydrogen requirements of the process. In accordance with a particularly preferred embodiment, conditions are controlled such that there also is produced a significant quantity of benzene as a valuable coproduct.

  20. System Losses Study - FIT (Fuel-cycle Integration and Tradeoffs)

    SciTech Connect (OSTI)

    Steven J. Piet; Nick R. Soelberg; Samuel E. Bays; Robert S. Cherry; Denia Djokic; Candido Pereira; Layne F. Pincock; Eric L. Shaber; Melissa C. Teague; Gregory M. Teske; Kurt G. Vedros

    2010-09-01T23:59:59.000Z

    This team aimed to understand the broad implications of changes of operating performance and parameters of a fuel cycle component on the entire system. In particular, this report documents the study of the impact of changing the loss of fission products into recycled fuel and the loss of actinides into waste. When the effort started in spring 2009, an over-simplified statement of the objective was “the number of nines” – how would the cost of separation, fuel fabrication, and waste management change as the number of nines of separation efficiency changed. The intent was to determine the optimum “losses” of TRU into waste for the single system that had been the focus of the Global Nuclear Energy Program (GNEP), namely sustained recycle in burner fast reactors, fed by transuranic (TRU) material recovered from used LWR UOX-51 fuel. That objective proved to be neither possible (insufficient details or attention to the former GNEP options, change in national waste management strategy from a Yucca Mountain focus) nor appropriate given the 2009-2010 change to a science-based program considering a wider range of options. Indeed, the definition of “losses” itself changed from the loss of TRU into waste to a generic definition that a “loss” is any material that ends up where it is undesired. All streams from either separation or fuel fabrication are products; fuel feed streams must lead to fuels with tolerable impurities and waste streams must meet waste acceptance criteria (WAC) for one or more disposal sites. And, these losses are linked in the sense that as the loss of TRU into waste is reduced, often the loss or carryover of waste into TRU or uranium is increased. The effort has provided a mechanism for connecting these three Campaigns at a technical level that had not previously occurred – asking smarter and smarter questions, sometimes answering them, discussing assumptions, identifying R&D needs, and gaining new insights. The FIT model has been a forcing function, helping the team in this endeavor. Models don’t like “TBD” as an input, forcing us to make assumptions and see if they matter. A major addition in FY 2010 was exploratory analysis of “modified open fuel” cycles, employing “minimum fuel treatment” as opposed to full aqueous or electrochemical separation treatment. This increased complexity in our analysis and analytical tool development because equilibrium conditions do not appear sustainable in minimum fuel treatment cases, as was assumed in FY 2009 work with conventional aqueous and electrochemical separation. It is no longer reasonable to assume an equilibrium situation exists in all cases.

  1. Microwave-enhanced chemical processes

    DOE Patents [OSTI]

    Varma, R.

    1990-06-19T23:59:59.000Z

    A process is disclosed for the disposal of toxic wastes including chlorinated hydrocarbons, comprising, establishing a bed of non-metallic particulates having a high dielectric loss factor. Intimate contact of the particulates and the toxic wastes at a temperature in excess of about 400 C in the presence of microwave radiation for a time sufficient breaks the hydrocarbon chlorine bonds. Detoxification values in excess of 80 are provided and further detoxification of the bed is followed by additional disposal of toxic wastes. 1 figure.

  2. images/logoetsf Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes and Graphene Perspectives

    E-Print Network [OSTI]

    Botti, Silvana

    images/logoetsf Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes and Graphene excitations Francesco Sottile #12;Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes excitations Francesco Sottile #12;Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes

  3. ANALYZING SURFACE ROUGHNESS DEPENDENCE OF LINEAR RF LOSSES

    SciTech Connect (OSTI)

    Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB, W& M College; Xu, Chen [JLAB, W& M College

    2012-09-01T23:59:59.000Z

    Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

  4. Loss of purity by wave packet scattering at low energies

    E-Print Network [OSTI]

    Jia Wang; C. K. Law; M. -C. Chu

    2006-01-06T23:59:59.000Z

    We study the quantum entanglement produced by a head-on collision between two gaussian wave packets in three-dimensional space. By deriving the two-particle wave function modified by s-wave scattering amplitudes, we obtain an approximate analytic expression of the purity of an individual particle. The loss of purity provides an indicator of the degree of entanglement. In the case the wave packets are narrow in momentum space, we show that the loss of purity is solely controlled by the ratio of the scattering cross section to the transverse area of the wave packets.

  5. Passive magnetic bearing element with minimal power losses

    DOE Patents [OSTI]

    Post, R.F.

    1998-12-08T23:59:59.000Z

    Systems employing passive magnetic bearing elements having minimal power losses are provided. Improved stabilizing elements are shown, employing periodic magnet arrays and inductively loaded circuits, but with improved characteristics compared to the elements disclosed in US Patent No. 5,495,221 entitled ``Dynamically Stable Magnetic Suspension/Bearing System.`` The improvements relate to increasing the magnitude of the force derivative, while at the same time reducing the power dissipated during the normal operation of the bearing system, to provide a passive bearing system that has virtually no losses under equilibrium conditions, that is, when the supported system is not subject to any accelerations except those of gravity. 8 figs.

  6. Passive magnetic bearing element with minimal power losses

    DOE Patents [OSTI]

    Post, Richard F. (Walnut Creek, CA)

    1998-01-01T23:59:59.000Z

    Systems employing passive magnetic bearing elements having minimal power losses are provided. Improved stabilizing elements are shown, employing periodic magnet arrays and inductively loaded circuits, but with improved characteristics compared to the elements disclosed in U.S. Patent No. 5,495,221 entitled "Dynamically Stable Magnetic Suspension/Bearing System." The improvements relate to increasing the magnitude of the force derivative, while at the same time reducing the power dissipated during the normal operation of the bearing system, to provide a passive bearing system that has virtually no losses under equilibrium conditions, that is, when the supported system is not subject to any accelerations except those of gravity.

  7. Interaction of the plasma tail of comet Bradfield 1979L on 1980 February 6 with a possibly flare-generated solar-wind disturbance

    SciTech Connect (OSTI)

    Niedner, M.B. Jr.; Brandt, J.C.; Zwickl, R.D.; Bame, S.J.

    1982-01-01T23:59:59.000Z

    Solar-wind plasma data from the ISEE-3 and Helios 2 spacecraft have been examined in order to explain a uniquely rapid 10/sup 0/ turning of the plasma tail of comet Bradfield 1979L on 1980 February 6. An earlier study conducted before the availability of in situ solar-wind data (Brandt et al., 1980) suggested that the tail position angle change occurred in response to a solar-wind velocity shear across which the polar component changed by approx. 50 km s/sup -1/. The present contribution confirms this result and further suggests that the comet-tail activity was caused by non-corotating, disturbed plasma flows probably associated with an Importance 1B solar flare.

  8. Reduction in tribological energy losses in the transportation and electric utilities sectors

    SciTech Connect (OSTI)

    Pinkus, O.; Wilcock, D.F.; Levinson, T.M.

    1985-09-01T23:59:59.000Z

    This report is part of a study of ways and means of advancing the national energy conservation effort, particularly with regard to oil, via progress in the technology of tribology. The report is confined to two economic sectors: transportation, where the scope embraces primarily the highway fleets, and electric utilities. Together these two sectors account for half of the US energy consumption. Goal of the study is to ascertain the energy sinks attributable to tribological components and processes and to recommend long-range research and development (R and D) programs aimed at reducing these losses. In addition to the obvious tribological machine components such as bearings, piston rings, transmissions and so on, the study also extends to processes which are linked to tribology indirectly such as wear of machine parts, coatings of blades, high temperature materials leading to higher cycle efficiencies, attenuation of vibration, and other cycle improvements.

  9. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    SciTech Connect (OSTI)

    Malumbela, Goitseone, E-mail: malumbela@mopipi.ub.b [Dpt. of Civil Eng., Univ. of Cape Town, Private Bag X3, Rondebosch, 7700 (South Africa); Alexander, Mark; Moyo, Pilate [Dpt. of Civil Eng., Univ. of Cape Town, Private Bag X3, Rondebosch, 7700 (South Africa)

    2010-09-15T23:59:59.000Z

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  10. Oligomerization process

    DOE Patents [OSTI]

    Smith, Jr., Lawrence A. (Bellaire, TX); hearn, Dennis (Houston, TX); Jones, Jr., Edward M. (Friendswood, TX)

    1991-01-01T23:59:59.000Z

    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300.degree. F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  11. Etherification process

    DOE Patents [OSTI]

    Smith, Jr., Lawrence A. (Houston, TX); Hearn, Dennis (Houston, TX); Jones, Jr., Edward M. (Friendswood, TX)

    1990-01-01T23:59:59.000Z

    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  12. Parton energy loss due to synchrotron-like gluon emission

    E-Print Network [OSTI]

    B. G. Zakharov

    2008-09-03T23:59:59.000Z

    We develop a quasiclassical theory of the synchrotron-like gluon radiation. Our calculations show that the parton energy loss due to the synchrotron gluon emission may be important in the jet quenching phenomenon if the plasma instabilities generate a sufficiently strong chromomagnetic field. Our gluon spectrum disagrees with that obtained by Shuryak and Zahed within the Schwinger's proper time method.

  13. DETERMINATION OF LOSS FACTORS IN A DEREGULATED SYSTEM Ashikur Bhuiya

    E-Print Network [OSTI]

    Saskatchewan, University of

    Alberta Electric System Operator e-mail: arb397@mail.usask.ca N. Chowdhury Department of Electrical to the operation and control of a system, typical tasks of an ISO may also include accepting bids from generators, providing access to the successful bidders and allocating transmission loss among the generators. Based

  14. Computationally Efficient Winding Loss Calculation with Multiple Windings, Arbitrary

    E-Print Network [OSTI]

    windings occurs at the level of individual turns, the method could be applied, but its advantages are lessComputationally Efficient Winding Loss Calculation with Multiple Windings, Arbitrary Waveforms and Two- or Three-Dimensional Field Geometry C. R. Sullivan From IEEE Transactions on Power Electronics

  15. PHENOLICS BUILDUP INHIBITS CARBON LOSS IN UNSATURATED PEATLANDS

    E-Print Network [OSTI]

    feedback loop" between carbon emission and drought in peatlands is down regulated in the long term. WePHENOLICS BUILDUP INHIBITS CARBON LOSS IN UNSATURATED PEATLANDS Hongjun Wang, Mengchi Ho, Neal carbon. Drought/drainage coupled with climate warming presents a vital threat to those stores

  16. Loss of Daylight Vision in Retinal Degeneration: Are

    E-Print Network [OSTI]

    Tabin, Cliff

    Loss of Daylight Vision in Retinal Degeneration: Are Oxidative Stress and Metabolic Dysregulation, particularly in cones, the type of photoreceptors that mediate daylight and color vision. The evidence, providing our daylight vision, and have many of the same features and vulnerabilities as rod photoreceptors

  17. The Energy Harvesting Multiple Access Channel with Energy Storage Losses

    E-Print Network [OSTI]

    Yener, Aylin

    The Energy Harvesting Multiple Access Channel with Energy Storage Losses Kaya Tutuncuoglu and Aylin considers a Gaussian multiple access channel with two energy harvesting transmitters with lossy energy storage. The power allocation policy maximizing the average weighted sum rate given the energy harvesting

  18. Way to reduce arc voltage losses in hybrid thermionic converters

    SciTech Connect (OSTI)

    Tskhakaya, V.K.; Yarygin, V.I.

    1982-03-01T23:59:59.000Z

    Experimental results are reported concerning the output and emission characteristics of the arc and hybrid regimes in a plane-parallel thermionic converter with Pt--Zr--O electrode pair. It is shown that arc voltage losses can be reduced to values below those obtainable in ordinary arc thermionic converters.

  19. Improved Calculation of Core Loss With Nonsinusoidal Waveforms

    E-Print Network [OSTI]

    . Comparison with experimental measure- ments in MnZn ferrite shows improved accuracy. The result may be op machines, transformers, inductors, and other static reactors, loss in the magnetic material is often pre of the flux density. It can be directly calculated from geometry and bulk resistivity in ferrites, and

  20. OLA -11.15,2012 DATA LOSS PREVENTION POLICY

    E-Print Network [OSTI]

    Kasman, Alex

    1 OLA -11.15,2012 DATA LOSS PREVENTION POLICY 1.0 PURPOSE This Policy establishes z e d disclosure of Protected Information by electronic means. The specific purposes of this Policy for monitoring and reporting compliance with the College's Privacy Policy (http://policy.cofc.edu/documents/11

  1. Panel Damping Loss Factor Estimation Using The Random Decrement Technique

    E-Print Network [OSTI]

    Dande, Himanshu Amol

    2010-12-10T23:59:59.000Z

    The use of the Random Decrement Technique (RDT) for estimating panel damping loss factors ranging from 1% to 10% is examined in a systematic way, with a focus on establishing the various parameters one must specify to use the technique to the best...

  2. Predicting pressure losses in two-phase flow

    E-Print Network [OSTI]

    Dietz, Frederic Henri

    1961-01-01T23:59:59.000Z

    be considered. C~ane and Carleton, Vogt 4 and White, and Pinkus have previously accounted for this loss by the "nodified" Fanning equation. 2 2S p ? sLD Vs J d s f where fs, the friction factor, accounts for the resistance of the par- ticles and walls...

  3. Assessing and Communicating the Loss of Biodiversity and

    E-Print Network [OSTI]

    Schmidt, Matthias

    Assessing and Communicating the Loss of Biodiversity and Ecosystem Services with Remote Sensing impacts on biodiversity, ecosystems and the services they provide. The summer school's goal is to learn about innovations in information technologies to generate information on changes of biodiversity

  4. AN INVESTIGATION OF CERTAIN THERMODYNAMIC LOSSES IN MINIATURE

    E-Print Network [OSTI]

    of gas temperatures and power losses for a compression volume that included a regenerative heat exchanger for flows between the piston/cylinder volume and the regenerator. The temperature profiles exhibited results for high pressure and low frequency were very unstable with significant high frequency components

  5. Tracking eelgrass loss in estuarine sediments of West Falmouth Harbor

    E-Print Network [OSTI]

    Vallino, Joseph J.

    lignin concentrations and trends in lignin 13C values reflect recent eelgrass cover change from three in sedimentary lignin concentration indicate recent eelgrass cover change when the lignin 13C reflects may determine whether or not a stressor will promote eelgrass loss. Key Words: Eelgrass, lignin

  6. The Community Loss Index: A New Social Indicator

    E-Print Network [OSTI]

    Qiu, Weigang

    and an aggregator of individ- ual experiences. Building on the relationship between loss and stress, the index at is growing due to mounting demand for accountability, outcome measures, evidence-based research, and indicators that reveal what works. In response, researchers like Jochen Albrecht and Laxmi Ramasubramanian ð

  7. Modelling and Measurements of Power Losses and Turbulence

    E-Print Network [OSTI]

    Pryor, Sara C.

    at Middelgrunden Offshore Wind Farm R. J. Barthelmie*, , S. T. Frandsen and M. N. Nielsen, Wind Energy Department and turbulence increase due to wind turbine wake interac- tions in large offshore wind farms is crucial interactions in large offshore wind farms is crucial to optimizing wind farm design. Power losses due

  8. 1. Introduction: current issues in hair loss-related disorders

    E-Print Network [OSTI]

    Chuong, Cheng-Ming

    1. Introduction: current issues in hair loss-related disorders 2. Basic biology of hair follicles 3. Physiological regeneration: modulating the regeneration of existing hair follicles by the extra-hair follicle environment and systemic hormone factors 4. Regeneration of hair fibers from existing follicles after hair

  9. Personality as a Moderating Variable Between Loss of Relationship and Subjective Well-Being in College Students

    E-Print Network [OSTI]

    Smith, Amanda Artell

    2010-10-12T23:59:59.000Z

    , Michael Duffy Committee Members, Daniel Brossart Arnold LeUnes Anita McCormick Head of Department, Victor Willson August 2010 Major Subject: Counseling Psychology iii ABSTRACT Personality as a Moderating Variable Between Loss... appreciation to my doctoral committee: Michael Duffy, Daniel Brossart, Anita McCormick, and Arnold LeUnes. Your continued support has meant a lot to me as I went through this process. I appreciate all the time and effort that was contributed...

  10. Theoretical mass loss rates of cool main-sequence stars

    E-Print Network [OSTI]

    V. Holzwarth; M. Jardine

    2006-11-14T23:59:59.000Z

    We develop a model for the wind properties of cool main-sequence stars, which comprises their wind ram pressures, mass fluxes, and terminal wind velocities. The wind properties are determined through a polytropic magnetised wind model, assuming power laws for the dependence of the thermal and magnetic wind parameters on the stellar rotation rate. We use empirical data to constrain theoretical wind scenarios, which are characterised by different rates of increase of the wind temperature, wind density, and magnetic field strength. Scenarios based on moderate rates of increase yield wind ram pressures in agreement with most empirical constraints, but cannot account for some moderately rotating targets, whose high apparent mass loss rates are inconsistent with observed coronal X-ray and magnetic properties. For fast magnetic rotators, the magneto-centrifugal driving of the outflow can produce terminal wind velocities far in excess of the surface escape velocity. Disregarding this aspect in the analyses of wind ram pressures leads to overestimations of stellar mass loss rates. The predicted mass loss rates of cool main-sequence stars do not exceed about ten times the solar value. Our results are in contrast with previous investigations, which found a strong increase of the stellar mass loss rates with the coronal X-ray flux. Owing to the weaker dependence, we expect the impact of stellar winds on planetary atmospheres to be less severe and the detectability of magnetospheric radio emission to be lower then previously suggested. Considering the rotational evolution of a one solar-mass star, the mass loss rates and the wind ram pressures are highest during the pre-main sequence phase.

  11. Plant and microbial controls on nitrogen retention and loss in a Humid Tropical Forest

    SciTech Connect (OSTI)

    Templer, P.; Silver, W.; Pett-Ridge, J.; DeAngelis, K.M.; Firestone, M.K.

    2009-09-15T23:59:59.000Z

    Humid tropical forests are generally characterized by the lack of nitrogen (N) limitation to net primary productivity, yet paradoxically have high potential for N loss. We conducted an intensive field experiment with {sup 15}NH{sub 4} and {sup 15}NO{sub 3} additions to highly weathered tropical forest soils to determine the relative importance of N retention and loss mechanisms. Over half of all the NH{sub 4}{sup +} produced from gross mineralization was rapidly converted to NO{sub 3}{sup -} during the process of gross nitrification. During the first 24 h plant roots took up 28 % of the N mineralized, dominantly as NH{sub 4}{sup +}, and were a greater sink for N than soil microbial biomass. Soil microbes were not a significant sink for added {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup -} during the first 24 hr, and only for {sup 15}NH{sub 4}{sup +} after 7 d. Patterns of microbial community composition, as determined by Terminal Restriction Fragment Length Polymorphism analysis, were weakly, but significantly correlated with nitrification and denitrification to N{sub 2}O. Rates of dissimilatory NO{sub 3}{sup -} reduction to NH{sub 4}{sup +} (DNRA) were high in this forest, accounting for up to 25 % of gross mineralization and 35 % of gross nitrification. DNRA was a major sink for NO{sub 3}{sup -} which may have contributed to the lower rates of N{sub 2}O and leaching losses. Despite considerable N conservation via DNRA and plant NH{sub 4}{sup +} uptake, the fate of approximately 45% of the NO{sub 3}{sup -} produced and 22% of the NH{sub 4}{sup +} produced were not measured in our fluxes, suggesting that other important pathways for N retention and loss (e.g., denitrification to N{sub 2}) are important in this system. The high proportion of mineralized N that was rapidly nitrified and the fates of that NO{sub 3}{sup -} highlight the key role of gross nitrification as a proximate control on N retention and loss in humid tropical forest soils. Furthermore, our results demonstrate the importance of the coupling between DNRA and plant uptake of NH{sub 4}{sup +} as a potential N conserving mechanism within tropical forests.

  12. The Fastmet[sup SM] direct reduction process

    SciTech Connect (OSTI)

    Lepinski, J.A.

    1993-01-01T23:59:59.000Z

    The Fastmet Process offers a simple and economical approach to producing direct reduced iron (DRI). It combines conventional equipment into a reliable ironmaking system. The process is ideally suited for processing U.S. iron oxide concentrates and coals. High iron yields are achievable due to the inherent ability to recycle in-plant fines and dust. Very low residence time of material in the rotary hearth furnace allows rapid adjustment of process parameters and minimal production loss from process upsets. Environmental impact is minimal. The paper gives a description of the process, then describes the economics, test facilities, test results, and scale-up.

  13. Energy loss characteristics of heavy ions in nitrogen, carbon dioxide, argon, hydrocarbon gases and tradescantia tissue

    E-Print Network [OSTI]

    Dennis, J A

    1971-01-01T23:59:59.000Z

    Energy loss characteristics of heavy ions in nitrogen, carbon dioxide, argon, hydrocarbon gases and tradescantia tissue

  14. THE 2011 FEBRUARY 15 X2 FLARE, RIBBONS, CORONAL FRONT, AND MASS EJECTION: INTERPRETING THE THREE-DIMENSIONAL VIEWS FROM THE SOLAR DYNAMICS OBSERVATORY AND STEREO GUIDED BY MAGNETOHYDRODYNAMIC FLUX-ROPE MODELING

    SciTech Connect (OSTI)

    Schrijver, Carolus J.; Title, Alan M. [Lockheed Martin Advanced Technology Center, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Aulanier, Guillaume; Pariat, Etienne; Delannee, Cecile, E-mail: schrijver@lmsal.com, E-mail: title@lmsal.com, E-mail: guillaume.aulanier@obspm.fr, E-mail: etienne.pariat@obspm.fr, E-mail: ceaulanier@voila.fr [LESIA, Observatoire de Paris, CNRS, UPMC, Universite Paris Diderot, 5 Place Jules Janssen, 92190 Meudon (France)

    2011-09-10T23:59:59.000Z

    The 2011 February 15 X2.2 flare and associated Earth-directed halo coronal mass ejection were observed in unprecedented detail with high resolution in spatial, temporal, and thermal dimensions by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory, as well as by instruments on the two STEREO spacecraft, then at near-quadrature relative to the Sun-Earth line. These observations enable us to see expanding loops from a flux-rope-like structure over the shearing polarity-inversion line between the central {delta}-spot groups of AR 11158, developing a propagating coronal front ('EIT wave'), and eventually forming the coronal mass ejection moving into the inner heliosphere. The observations support the interpretation that all of these features, including the 'EIT wave', are signatures of an expanding volume traced by loops (much larger than the flux rope only), surrounded by a moving front rather than predominantly wave-like perturbations; this interpretation is supported by previously published MHD models for active-region and global scales. The lateral expansion of the eruption is limited to the local helmet-streamer structure and halts at the edges of a large-scale domain of connectivity (in the process exciting loop oscillations at the edge of the southern polar coronal hole). The AIA observations reveal that plasma warming occurs within the expansion front as it propagates over quiet Sun areas. This warming causes dimming in the 171 A (Fe IX and Fe X) channel and brightening in the 193 and 211 A (Fe XII-XIV) channels along the entire front, while there is weak 131 A (Fe VIII and Fe XXI) emission in some directions. An analysis of the AIA response functions shows that sections of the front running over the quiet Sun are consistent with adiabatic warming; other sections may require additional heating which MHD modeling suggests could be caused by Joule dissipation. Although for the events studied here the effects of volumetric expansion are much more obvious than true wave phenomena, we discuss how different magnetic environments within and around the erupting region can lead to the signatures of either or both of these aspects.

  15. Boundary-Layer Stability and Transition on a Flared Cone in a Mach 6 Quiet Wind Tunnel

    E-Print Network [OSTI]

    Hofferth, Jerrod William

    2013-05-15T23:59:59.000Z

    A key remaining challenge in the design of hypersonic vehicles is the incomplete understanding of the process of boundary-layer transition. Turbulent heating rates are substantially higher than those for a laminar boundary layer, and large...

  16. 702 IEEEJOURNAL OF QUAKTUM ELECTRONICS OCTOBER phases of the q pump modes. asis the single pass power loss of the

    E-Print Network [OSTI]

    Teich, Malvin C.

    power loss of the signal modes, and allidler modes are assumed to have the same single pass loss ai. K

  17. Characteristic losses in metals: Al, Be, and Ni

    SciTech Connect (OSTI)

    Madden, H.H.; Landers, R.; Kleiman, G.G. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6165, 13081-970 Campinas, Sao Paulo, Brasil] [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6165, 13081-970 Campinas, Sao Paulo, Brasil; Zehner, D.M. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6057 (United States)] [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6057 (United States)

    1998-07-01T23:59:59.000Z

    Information about the {ital occupied} portion of the surface density of states of materials can be derived from electron-excited Auger electron spectroscopy (AES), which is a standard experimental technique in most surface science laboratories. Surface sensitive experimental techniques that provide information regarding the {ital unoccupied} portion of the surface density of states are often not standard and are not so readily available. Here we explore the possibility of utilizing the same experimental equipment as in AES to derive information about the unoccupied portion of the surface density of states from a characteristic loss spectroscopy, in particular, from core-level inelastic electron-scattering spectroscopy (CLIESS). An important application of this technique is in comparative studies. CLIESS spectra from clean surfaces of aluminum, beryllium and nickel are presented. These data were taken in the first-derivative mode using the reflection of monoenergetic primary beams of 450 eV energy for Be, and 300 eV for Al and Ni. The Al and Be spectra had to be extracted from overlapping plasmon signals using synthesized plasmon spectra based on the behavior of these spectra between the elastic peak energy and the respective core level threshold energies. After applying loss-deconvolution techniques to remove secondary loss spectral distortions, integral spectra were obtained which compared well to corresponding experimental soft x-ray absorption and transmission electron-energy loss data as well as to theoretical calculations of the unoccupied density-of-states for these materials. Comparison similarities as well as some differences are discussed. Finally, in order to illustrate the potential these signals have in serving as {open_quotes}fingerprints{close_quotes} of surface chemistry, derivative metal-CLIESS curves for the three oxide surfaces of the metals are also presented. {copyright} {ital 1998 American Vacuum Society.}

  18. Submillimeter residual losses in high-{Tc} superconductors

    SciTech Connect (OSTI)

    Miller, D.

    1993-09-01T23:59:59.000Z

    Bolometry was used obtain accurate submillimeter residual loss data for epitaxial films of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO), Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10}, Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} (TCBCO), and Ba{sub 0.6}K{sub 0.4}BiO{sub 3} (BKBO). We were able to fit the absorptivity measured for Nb films to an Eliashberg strong coupling calculation; excellent agreement resulted between parameters from best fits and measured Residual Resistivity Ratio. Microwave surface resistance measurements made on the same YBCO and TCBCO films are in excellent agreement with submillimeter measurements. Absorptivities for all YBCO films studied are qualitatively similar, increasing smoothly with frequency, with no gap-like features below the well known absorption edge at 450 cm{sup {minus}1}. Losses in YBCO films were fit to a weakly coupled grain model for the a-b plane conductivity. Strong phonon structure was observed in TCBCO films between 60 and 700 cm{sup {minus}1} (2 THz and 23 THz); these losses could not be fitted to the simple weakly coupled grain model, in contrast to the case for other high-{Tc} superconductors where phonon structure observed in ceramics are is absent in epitaxial oriented films and crystals because of electronic screening due to high conductivity of a-b planes. Absorptivity data for the BKBO films all show a strong absorption onset near the BCS tunneling gap of 3.5 k{sub B}{Tc}. Comparison with strong coupling Eliashberg predictions and of a Kramers-Kronig analysis indicate that the absorption onset is consistent with a superconducting energy gap. Effects of magnetic field on residual losses in YBCO films show a resonant absorption feature in vicinity of predicted

  19. Energy-Efficiency Options for Insurance Loss Prevention

    SciTech Connect (OSTI)

    Mills, E. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Knoepfel, I. [Swiss Reinsurance Co., Zurich (Switzerland)

    1997-06-09T23:59:59.000Z

    Energy-efficiency improvements offer the insurance industry two areas of opportunity: reducing ordinary claims and avoiding greenhouse gas emissions that could precipitate natural disaster losses resulting from global climate change. We present three vehicles for taking advantage of this opportunity, including research and development, in- house energy management, and provision of key information to insurance customers and risk managers. The complementary role for renewable energy systems is also introduced.

  20. BONE LOSS IN RELATION TO HYPOTHALAMIC ATROPHY IN ALZHEIMER'S DISEASE

    E-Print Network [OSTI]

    Loskutova, Natalia Y.

    2011-05-12T23:59:59.000Z

    considerable burden on the health system, patients, and caregivers. 1.2 Alzheimer’s Disease and Bone Loss Bone health is an important issue in aging and AD. Osteoporosis–related fractures are among the major health and socioeconomic concerns in aging... of bone fractures, and a determining factor in clinical diagnosis of osteoporosis (Ammann and Rizzoli 2003). Several studies in women suggest that low BMD is associated with poorer cognitive function and subsequent cognitive decline (Yaffe, Browner et al...