Type Ia Supernovae and the Hubble Constant
D. Branch
1998-01-08T23:59:59.000Z
The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant ($H_0$). SNe Ia are well suited for measuring $H_0$. A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than $\\sigma_{obs}(M_B) \\simeq \\sigma_{obs}(M_V) \\simeq 0.3$ mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways --- empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at $M_B \\simeq M_V \\simeq -19.4$ or -19.5. Various ways that have been used to match Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed out in the Hubble flow have given values of $H_0$ distributed throughout the range 54 to 67 km/s Mpc$^{-1}$. Astronomers who want a consensus value of $H_0$ from SNe Ia with conservative errors could, for now, use $60 \\pm 10$ km/s Mpc^{-1}$.
The Hubble Constant from Type Ia Supernovae in Early-Type Galaxies
Tom Richtler; Georg Drenkhahn
1999-09-07T23:59:59.000Z
Type Ia supernovae (SNe) are the best standard candles available today in spite of an appreciable intrinsic variation of their luminosities at maximum phase, and of probably non-uniform progenitors. For an unbiased use of type Ia SNe as distance indicators it is important to know accurately how the decline rate and colour at maximum phase correlate with the peak brightness. In order to calibrate the Hubble diagram of type Ia SNe, i.e. to derive the Hubble constant, one needs to determine the absolute brightness of nearby type Ia SNe. Globular cluster systems of early type Ia host galaxies provide suitable distance indicators. We discuss how Ia SNe can be calibrated and explain the method of Globular Cluster Luminosity Functions (GCLFs). At present, the distance to the Fornax galaxy cluster is most important for deriving the Hubble constant. Our present data indicate a Hubble constant of H_0=72+-4 km/s/Mpc. As an appendix, we summarise what is known about absolute magnitudes of Ia's in late-type galaxies.
Hardy–Sobolev Type Inequalities with Sharp Constants in Carnot ...
2010-06-22T23:59:59.000Z
nonlinear case p = 2. We also obtain a sharp inequality of Hardy–Sobolev type. Keywords Hardy type inequalities·Carnot groups·Carnot–Carathéodory spaces·.
Fine-structure constant constraints on Bekenstein-type models
P. M. M. Leal; C. J. A. P. Martins; L. B. Ventura
2014-07-15T23:59:59.000Z
Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\\alpha$, are an area of much increased recent activity, following some indications of possible spacetime variations at the few parts per million level. Here we obtain updated constraints on the Bekenstein-Sandvik-Barrow-Magueijo model, which is arguably the simplest model allowing for $\\alpha$ variations. Recent accurate spectroscopic measurements allow us to improve previous constraints by about an order of magnitude. We briefly comment on the dependence of the results on the data sample, as well as on the improvements expected from future facilities.
Analysis of error in using fractured gas well type curves for constant pressure production
Schkade, David Wayne
1987-01-01T23:59:59.000Z
ANALYSIS DF ERROR IN USING FRACTURED GAS WELL TYPE CURVES FOR CONSTANT PRESSURE PRODUCTION A Thesis by DAVID WAYNE SCHKADE Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1987 Major Subject: Petroleum Engineering ANALYSIS OF ERROR IN USING FRACTURED GAS WELL TYPE CURVES FOR CONSTANT PRESSURE PRDDUCTION A Thesis by DAVID WAYNE SCHKADE Approved as to style and content by: S. A. Ho lditch...
Goobar, A.
2008-01-01T23:59:59.000Z
at z = 1. uncertainty for supernovae at z = 1. mR Adding theMass Density .Q Using Type Ia Supernovae A. Goobar and S.Density Q Using Type Ia Supernovae Ariel Goobar l and Saul
Elastic constants determined by nanoindentation for p-type thermoelectric half-Heusler
Gahlawat, S.; Wheeler, L.; White, K. W., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); He, R.; Chen, S.; Ren, Z. F., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States)
2014-08-28T23:59:59.000Z
This paper presents a study of the elastic properties of the p-type thermoelectric half-Heusler material, Hf{sub 0.44}Zr{sub 0.44}Ti{sub 0.12}CoSb{sub 0.8}Sn{sub 0.2}, using nanoindentation. Large grain-sized polycrystalline specimens were fabricated for these measurements, providing sufficient indentation targets within single grains. Electron Backscatter Diffraction methods indexed the target grains for the correlation needed for our elastic analysis of individual single crystals for this cubic thermoelectric material. Elastic properties, including the Zener ratio and the Poisson ratio, obtained from the elasticity tensor are also reported.
Design optimization of cable-stayed bridges
Bessas, Georgios
2006-01-01T23:59:59.000Z
The goal of this thesis is to achieve a basic understanding of cable-stayed systems. Issues to be treated are the diachronic evolution of cable-stayed bridges, including the advantages, the limitations and the basic design ...
Staying Informed | Department of Energy
Office of Environmental Management (EM)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,Separation 23 362 334DepartmentCivilianAffairs,Site TransitionDepartmentKatrinaDeliveryCellonof theStaying Informed
Timely PTS Applications Critical to Staying Navy
Timely PTS Applications Critical to Staying Navy Navy Personnel Command (NPC) is reminding commands and Sailors that submitting Perform to Serve (PTS) applications is the key to being able to stay Navy/10 explains how PTS is used to shape the Navy, and includes all business rules concerning. Commands must
Richard G. Forbes
2015-02-25T23:59:59.000Z
In the 1940s/50s, Landau and Lifschitz (LL) published in their Quantum Mechanics textbook what is now a well known formula for the rate-constant for the electrostatic field ionization (ESFI) of a hydrogen atom in its ground electronic state. This formula is widely regarded as correct in the low field limit, and has played a significant role in development of ESFI theory. The formula was originally derived and presented in the atomic units system, with the hydrogen ionization energy I_H set equal to (1/2), making it impossible to determine by inspection to what power I_H is raised in its pre-exponential. Knowledge of this power would be useful in the context of near-surface ESFI, where significant image-force-induced shifts in effective ionization energy can occur. Also, large numbers of applied scientists and engineers work with ESFI as a process of technological importance, but cannot nowadays be expected to have familiarity with the Gaussian or atomic units equation systems. In the 1970s, what is now called the International System of Quantities (ISQ), which includes the equation system behind SI units, was internationally adopted as the primary system for university teaching and for communication of scientific equations between theoreticians and applied scientists and engineers. However, 40 years on, no transparent derivation of an ISQ equivalent of the LL formula is easily found in the literature. This tutorial paper presents a detailed ISQ derivation, finds that ionization energy appears in the pre-exponential as I_H to the power (7/2) (not 5/2, as sometimes stated) and defines a universal "tunnelling ionization constant" that appears in the ISQ formula pre-exponential. It is shown how this formula relates to the "attempt frequency" form often used to describe rate-constants for tunnelling processes, and an ISQ expression is given for the motive energy in the related JWKB integral.
Frank Znidarsic
2000-11-12T23:59:59.000Z
A Bose condensate of electrons may exist in nickel hydrogen and palladium hydrogen systems. The motion constants associated with the gravitational and nuclear forces motion tend toward the electromagnetic in these systems. The change in the motion constants produces unexpected gravitomagnetic and nuclear affects.
Brad K. Gibson; Peter B. Stetson; Wendy L. Freedman; Jeremy R. Mould; Robert C. Kennicutt, Jr.; John P. Huchra; Shoko Sakai; John A. Graham; Caleb I. Fassett; Daniel D. Kelson; Laura Ferrarese; Shaun M. G. Hughes; Garth D. Illingworth; Lucas M. Macri; Barry F. Madore; Kim M. Sebo; Nancy A. Silbermann
1999-08-13T23:59:59.000Z
Cepheid-based distances to seven Type Ia supernovae (SNe)-host galaxies have been derived using the standard HST Key Project on the Extragalactic Distance Scale pipeline. For the first time, this allows for a transparent comparison of data accumulated as part of three different HST projects, the Key Project, the Sandage et al. Type Ia SNe program, and the Tanvir et al. Leo I Group study. Re-analyzing the Tanvir et al. galaxy and six Sandage et al. galaxies we find a mean (weighted) offset in true distance moduli of 0.12+/-0.07 mag -- i.e., 6% in linear distance -- in the sense of reducing the distance scale, or increasing H0. Adopting the reddening-corrected Hubble relations of Suntzeff et al. (1999), tied to a zero point based upon SNe~1990N, 1981B, 1998bu, 1989B, 1972E and 1960F and the photometric calibration of Hill et al. (1998), leads to a Hubble constant of H0=68+/-2(random)+/-5(systematic) km/s/Mpc. Adopting the Kennicutt et al. (1998) Cepheid period-luminosity-metallicity dependency decreases the inferred H0 by 4%. The H0 result from Type Ia SNe is now in good agreement, to within their respective uncertainties, with that from the Tully-Fisher and surface brightness fluctuation relations.
Staying the Course | Department of Energy
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of Wnt Recognition by Frizzled SSRLDr. Donald L.About Â»Stay alert in
Win-stay lose-shift strategy in formation changes in football
Tamura, Kohei
2015-01-01T23:59:59.000Z
Managerial decision making is likely to be a dominant determinant of performance of teams in team sports. Here we use Japanese and German football data to investigate correlates between temporal patterns of formation changes across matches and match results. We found that individual teams and managers both showed win-stay lose-shift behavior, a type of reinforcement learning. In other words, they tended to stick to the current formation after a win and switch to a different formation after a loss. In addition, formation changes did not affect the results of succeeding matches in most cases. The results indicate that a swift implementation of a new formation in the win-stay lose-shift manner may not be a successful managerial rule of thumb.
ORISE: Stay Rates of Foreign Doctorate Recipients from U.S. Universities
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirtA Journey Inside the Complex(MARSSIM) Site InvestigationTypeORISE ScienceStay Rates of Foreign
Marine Policy 28 (2004) 311324 Modeling entry, stay, and exit decisions of the longline fishers in
Hawai'i at Manoa, University of
2004-01-01T23:59:59.000Z
Marine Policy 28 (2004) 311324 Modeling entry, stay, and exit decisions of the longline fishers 2003; accepted 25 September 2003 Abstract A behavioral study on the entry, stay and exit decisions. The empirical results confirm that the entry, stay, and exit decisions are significantly associated
Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2007
Dr. Michael G. Finn
2010-01-04T23:59:59.000Z
Study of the stay rate in the United States of foreign nationals receiving their S/E doctorates from U.S. universities. This study has estimated stay rates in 2007 for persons receiving a doctorate one, two, five, and ten years previously. The two-year stay rate (for 2005 graduates) recovered from the decline experienced earlier in the decade. The five-year stay rate (for 2002 graduates) is lower; the ten-year stay rate (for 1997 graduates) reached a new high.
Stay Warm in Your Apartment | Department of Energy
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 Center Home Page on DeliciousPlasma |EfficiencyCR-B-99-02Contact on2009:DOESR-07-01 SpecialDepartment ofBlueprintStay Warm in Your
Stay alert in the Pammel Drive crosswalks | The Ames Laboratory
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of Wnt Recognition by Frizzled SSRLDr. Donald L.About Â»Stay alert in the
Cosmology with Varying Constants
C. J. A. P. Martins
2000-08-18T23:59:59.000Z
I motivate and discuss some recent work on theories with varying constants, and consider some possible observational consequences and tests. Particular emphasis is given to models which can (almost) exactly mimic the predictions of standard inflationary models.
Chinese supercomputer stays No. 1, Titan at ORNL still No. 2...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Chinese supercomputer stays No. 1, Titan at ORNL still No. 2 November 18, 2014 For the fourth consecutive time, Tianhe-2, a supercomputer developed by China's National University...
R. L. Collins
2006-01-10T23:59:59.000Z
Hubble plots of the distance of stellar objects vs. recession velocity normally assume the red shift is wholly Doppler and ignore any gravitational contribution. This is unwarranted: gravity and Doppler velocity red shifts are found to be separable and contribute about equally. A recent data set, to Z=1.2, by Riess (1), was analyzed. Upon plotting distance vs. Doppler velocity, the slope of the Hubble plot increases. The Hubble plot is also curved, upwards, and this can be understood in terms of the relativistic metric changes of the space through which the light travels. On fitting the data to a simple model of a big bang of constant density, this finds the total mass of the big bang is M=21.1x10^52 kg. When present actual distance is plotted vs. Doppler velocity, the plot is linear and agrees with Hubble's concept, without acceleration. Time since the big bang is longer than the 14 billion years that had been thought, 23.5 billion years. The Hubble constant hence shrinks from Ho=71 to Ho=41.6. This is an independent affirmation of a recent CMB finding of a low Ho=35.
Unitaxial constant velocity microactuator
McIntyre, T.J.
1994-06-07T23:59:59.000Z
A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment is disclosed. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-nanometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment. 10 figs.
Unitaxial constant velocity microactuator
McIntyre, Timothy J. (Knoxville, TN)
1994-01-01T23:59:59.000Z
A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-manometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment.
Samuels, Fallon M. (Fallon Michele)
2007-01-01T23:59:59.000Z
A history and theory of cable-stayed bridges in the context of a cultural discourse on civil construction projects' value, this thesis studies the significance of cable-stayed bridge designs to 'value engineering' objectives ...
Genetic analysis of the Sorghum bicolor stay-green drought tolerance trait
Harris, Karen Ruth
2009-05-15T23:59:59.000Z
yellow seeds. In addition, a subset of the regions containing favorable alleles for stay- green from the genotype BTx642 were over represented in stay-green breeding lines. Nearly isogenic lines containing favorable alleles from BTx642 for Stg1, Stg2..., Stg3, and Stg4 in a RTx7000 (senescent) background were characterized and each NIL was shown to exhibit a stay-green phenotype. Based in part on this information, fine-mapping of Stg1 was undertaken by crossing the Stg1 NIL to RTx7000. Overall...
Winter Weather Preparedness Have a Plan -Make a Kit -Stay Informed
Oklahoma, University of
Winter Weather Preparedness Have a Plan - Make a Kit - Stay Informed during winter weather. Move livestock to sheltered areas with non-frozen drinking. If necessary insulate walls and attic. Caulk and weather-strip doors and windowsills
Non-Destructive Evaluation of Bridge Stay Cable and External Post-Tensioning Systems
McCoy, Katlyn Mae
2014-10-09T23:59:59.000Z
such as corrosion, steel strand and wire breakage, tendon section loss, voids in the grout, water infiltration, and other undesired grout conditions can go undetected in nontransparent stay cable and external PT ducts without proper inspection. In this research...
Stay on marked paths to avoid poison ivy. Watch young children carefully around river and creeks.
Shyy, Wei
Caution · Stay on marked paths to avoid poison ivy. · Watch young children carefully around river or outdoor cooking are not permitted. Poison Ivy Hours · Trails and gardens open 8 am to dusk. · Conservatory
Non-Destructive Evaluation of Bridge Stay Cable and External Post-Tensioning Systems
McCoy, Katlyn Mae
2014-10-09T23:59:59.000Z
such as corrosion, steel strand and wire breakage, tendon section loss, voids in the grout, water infiltration, and other undesired grout conditions can go undetected in nontransparent stay cable and external PT ducts without proper inspection. In this research...
Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2005
Mike Finn
2008-02-01T23:59:59.000Z
This is the latest in a series of studies conducted for the National Science Foundation to estimate the proportion of foreign science / engineering doctorate recipients from U.S. universities who stayed in the United States after graduation. Sixty-six percent of those who graduated in 2003 were still in the United States in 2005, a 5 percent decline since the last report. But the five-year stay rate continues to climb, now at 68 percent.
Time-Varying Fine-Structure Constant Requires Cosmological Constant
R. W. Kuhne
1999-08-31T23:59:59.000Z
Webb et al. presented preliminary evidence for a time-varying fine-structure constant. We show Teller's formula for this variation to be ruled out within the Einstein-de Sitter universe, however, it is compatible with cosmologies which require a large cosmological constant.
Dimensionality and the Cosmological Constant
Z. C. Wu
2006-05-01T23:59:59.000Z
In the Kaluza-Klein model with a cosmological constant and a flux, the external spacetime and its dimension of the created universe from a $S^s \\times S^{n-s}$ seed instanton can be identified in quantum cosmology. One can also show that in the internal space the effective cosmological constant is most probably zero.
QCD coupling constants and VDM
Erkol, G.; Ozpineci, A.; Zamiralov, V. S. [Laboratory for Fundamental Research, Ozyegin University, Istanbul (Turkey); Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Skobeltsyn Institute of Nuclear Physics, Lomonosov MSU, Moscow (Russian Federation)
2012-10-23T23:59:59.000Z
QCD sum rules for coupling constants of vector mesons with baryons are constructed. The corresponding QCD sum rules for electric charges and magnetic moments are also derived and with the use of vector-meson-dominance model related to the coupling constants. The VDM role as the criterium of reciprocal validity of the sum rules is considered.
Varying constants, Gravitation and Cosmology
Jean-Philippe Uzan
2010-09-28T23:59:59.000Z
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
March 2012 BEE CULTURE 29 unlucky spider struggling to stay in
Delaplane, Keith S.
to waste venom on us. Each time a spider discharges venom, it can take up to two weeks for the venomMarch 2012 BEE CULTURE 29 unlucky spider struggling to stay in her web, that can send shivers up of the details may be a bit fuzzy. It was 1998 when he spoke to our department. Built back in 1929, the Geor
Evaluating Risk of Terrorist Attack on a Cable Stayed Bridge: A Probabilistic Structural
Bhattacharya, Baidurya
Evaluating Risk of Terrorist Attack on a Cable Stayed Bridge: A Probabilistic Structural Analysis and administrators are able to evaluate risks to infrastructure in their jurisdiction in a rational manner. This will enable them to take optimal actions to manage these risks given budgetary constraints. This paper
Stay protected when connected Visit security.duke.edu for more information.
McShea, Daniel W.
Stay protected when connected Visit security.duke.edu for more information. Follow these guidelines Visit security.duke.edu for more information. Follow these tips for securing mobile devices: iOS 6/software/. Windows Mac Another free option: Microsoft Security Essentials: http://windows.microsoft.com/en- US/windows/products/security
DAMAGE IDENTIFICATION IN A BENCHMARK CABLE-STAYED BRIDGE USING THE INTERPOLATION METHOD
Boyer, Edmond
DAMAGE IDENTIFICATION IN A BENCHMARK CABLE-STAYED BRIDGE USING THE INTERPOLATION METHOD Marco mariagiuseppina.limongelli@polimi.it ABSTRACT In this paper the damage localization algorithm based on Operational Deformed Shapes (ODS) and known as Interpolation Damage Detection Method (IDDM), is applied
How fundamental are fundamental constants?
M. J. Duff
2014-12-17T23:59:59.000Z
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, alpha. For example, the Standard Model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers, scales... they use to measure them. Dimensional constants, on the other hand, such as h, c, G, e, k..., are merely human constructs whose number and values differ from one choice of units to the next. In this sense only dimensionless constants are "fundamental". Similarly, the possible time variation of dimensionless fundamental "constants" of nature is operationally well-defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might disagree depending on their apparatus. All these confusions disappear if one asks only unit-independent questions. We provide a selection of opposing opinions in the literature and respond accordingly.
How fundamental are fundamental constants?
Duff, M J
2014-01-01T23:59:59.000Z
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, alpha. For example, the Standard Model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers, scales... they use to measure them. Dimensional constants, on the other hand, such as h, c, G, e, k..., are merely human constructs whose number and values differ from one choice of units to the next. In this sense only dimensionless constants are "fundamental". Similarly, the possible time variation of dimensionless fundamental "constants" of nature is operationally well-defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might...
Hardy–Sobolev Type Inequalities with Sharp Constants in Carnot ...
2011-03-02T23:59:59.000Z
Jun 24, 2010 ... To introduce our main result consider a system X = {X1, ..., Xm} of C ... (personal communication), where a similar construction was carried in ...
The Effects of Quantum Entropy on the Bag Constant
Miller, D E; Miller, David E.; Tawfik, Abdel-Nasser
2003-01-01T23:59:59.000Z
The effects of quantum entropy on the bag constant are studied at low temperatures and small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag constant without the quantum entropy almost does not change with the temperature and the quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant.
Distinct Cyclin D Genes Show Mitotic Accumulation or Constant Levels of Transcripts in Tobacco
Murray, J.A.H.
Distinct Cyclin D Genes Show Mitotic Accumulation or Constant Levels of Transcripts in Tobacco-type cyclins accumulate peri- odically during the S, G2, and early M phases (A types) or G2 and early M phases
FROM CONSTANT TO NON-DEGENERATELY VANISHING MAGNETIC FIELDS IN SUPERCONDUCTIVITY
the distribution of superconductivity in a type II superconductor submitted to a vari- able magnetic fieldFROM CONSTANT TO NON-DEGENERATELY VANISHING MAGNETIC FIELDS IN SUPERCONDUCTIVITY BERNARD HELFFER- tivity in a type II superconductor subjected to a constant magnetic field. The second function describes
Renormalization of Newton's constant and Particle Physics
X. Calmet
2010-02-02T23:59:59.000Z
We report on particle physics applications of the renormalization group equation of Newton's constant.
Johnson, Eric N.
A DISPLAY CONCEPT FOR STAYING AHEAD OF THE AIRPLANE Eric N. Johnson, Lockheed Martin Aeronautical Systems, Marietta, Georgia David C. Hansen, Lockheed Martin Aeronautical Systems, Marietta, Georgia manner required for many aerospace applications. Considerably more data fusion, data prediction, alerting
Staying Competitive in the 90's: How to Make Public Involvement Work for Your Energy Project
Loveless, K. W.
STAYING COMPETITIVE IN THE 90'S: HOW TO MAKE PUBLIC INVOL VEMENT WORK FOR YOUR ENERGY PROJECT Kat11Y Wood LOVl;!cSS, Prcsidl;l1t, Loveless EnLerprises, Inc., Salt Lake City, Utah ABSTRACT Gone are the days when energy companies could develop... in Washington, D. c., and Denver. She has been analyzing, planning, conducting public involvement events for more than 2 decades. For a free copy of more public involvement techniques call 801-363-1807 or write: 267 E. North Sandrun Rd.,Salt Lake City, Utah...
Towards the cosmological constant problem
Eun Kyung Park; Pyung Seong Kwon
2014-12-15T23:59:59.000Z
We apply a new self-tuning mechanism to the well-known Kachru-Kallosh-Linde-Trivedi (KKLT) model to address the cosmological constant problem. In this mechanism the cosmological constant $\\lambda$ contains a supersymmetry breaking term ${\\mathcal E}_{\\rm SB}$ besides the usual scalar potential ${\\mathcal V}_{\\rm scalar}$ of the $N=1$ supergravity, which is distinguished from the usual theories where $\\lambda$ is directly identified with ${\\mathcal V}_{\\rm scalar}$ alone. Also in this mechanism, whether $\\lambda$ vanishes or not is basically determined by the tensor structure of the scalar potential density, not by the zero or nonzero values of the scalar potential itself. As a result of this application we find that the natural scenario for the vanishing $\\lambda$ of the present universe is to take one of the AdS (rather than dS) vacua of KKLT as the background vacuum of our present universe. This AdS vacuum scenario does not suffer from the problematics of the dS vacua of KKLT. The background vacuum is stable both classically and quantum mechanically (no tunneling instabilities), and the value $\\lambda =0$ is also stable against quantum corrections because in this scenario the perturbative corrections of ${\\mathcal V}_{\\rm scalar}$ and quantum fluctuations $\\delta_Q {\\hat I}_{\\rm brane}^{(NS)} + \\delta_Q {\\hat I}_{\\rm brane}^{(R)}$ on the branes are all gauged away by an automatic cancelation between ${\\mathcal V}_{\\rm scalar} + \\delta_Q {\\hat I}_{\\rm brane}^{(NS)} + \\delta_Q {\\hat I}_{\\rm brane}^{(R)}$ and ${\\mathcal E}_{\\rm SB}$.
An Issue to the Cosmological Constant Problem
R. Triay
2005-04-07T23:59:59.000Z
According to general relativity, the present analysis shows on geometrical grounds that the cosmological constant problem is an artifact due to the unfounded link of this fundamental constant to vacuum energy density of quantum fluctuations.
MINIMAL SURFACES, SURFACES OF CONSTANT MEAN ...
2003-09-25T23:59:59.000Z
constant Ciso(G) > 0 of Theorem 12.1, for any go ? G, R > 0, one has for every ... constant Ciso = Ciso(G) > 0 as in Theorem 12.4, for every X-Caccioppoli set E ...
PHYSICS & ASTRONOMY DATA CARD Physical Constants
Greenaway, Alan
's constant h 6.626 x 10-34 J s Ñ= h/2 1.055 x 10-34 J s Avogadro's constant NA 6.022 x 1023 mol-1 Boltzmann
Constant time algorithms in sparse graph model
Nguyen, Huy Ngoc, Ph. D. Massachusetts Institute of Technology
2010-01-01T23:59:59.000Z
We focus on constant-time algorithms for graph problems in bounded degree model. We introduce several techniques to design constant-time approximation algorithms for problems such as Vertex Cover, Maximum Matching, Maximum ...
CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS...
Office of Scientific and Technical Information (OSTI)
CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS FOR THE HUBBLE CONSTANT Citation Details In-Document Search Title: CEPHEID CALIBRATIONS OF MODERN TYPE Ia...
Ferraro, R. J.; Osborne, R.; Stephens, R.
) an increase in loads that use power electronics in some type of power conversion configuration [1][2]. This paper presents applications of the constant-voltage transformer (CVT) for mitigating the effects of electric service voltage sags on industrial...
Emergent cosmological constant from colliding electromagnetic waves
Halilsoy, M.; Mazharimousavi, S. Habib; Gurtug, O., E-mail: mustafa.halilsoy@emu.edu.tr, E-mail: habib.mazhari@emu.edu.tr, E-mail: ozay.gurtug@emu.edu.tr [Department of Physics, Eastern Mediterranean University, Gazimavgusa, north Cyprus, Mersin 10 (Turkey)
2014-11-01T23:59:59.000Z
In this study we advocate the view that the cosmological constant is of electromagnetic (em) origin, which can be generated from the collision of em shock waves coupled with gravitational shock waves. The wave profiles that participate in the collision have different amplitudes. It is shown that, circular polarization with equal amplitude waves does not generate cosmological constant. We also prove that the generation of the cosmological constant is related to the linear polarization. The addition of cross polarization generates no cosmological constant. Depending on the value of the wave amplitudes, the generated cosmological constant can be positive or negative. We show additionally that, the collision of nonlinear em waves in a particular class of Born-Infeld theory also yields a cosmological constant.
Constant voltage electro-slag remelting control
Schlienger, Max E. (Albuquerque, NM)
1996-01-01T23:59:59.000Z
A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.
Cosmological Constant and Axions in String Theory
Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC
2006-08-18T23:59:59.000Z
String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.
Constant voltage electro-slag remelting control
Schlienger, M.E.
1996-10-22T23:59:59.000Z
A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an electrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable. 1 fig.
Berryman, J.G.; Nakagawa, S.
2009-11-20T23:59:59.000Z
Poroelastic analysis has traditionally focused on the relationship between dry or drained constants which are assumed known and the saturated or undrained constants which are assumed unknown. However, there are many applications in this field of study for which the main measurements can only be made on the saturated/undrained system, and then it is uncertain what the eects of the uids were on the system, since the drained constants remain a mystery. The work presented here shows how to deduce drained constants from undrained constants for anisotropic systems having symmetries ranging from isotropic to orthotropic. Laboratory ultrasound data are then inverted for the drained constants in three granular packings: one of glass beads, and two others for distinct types of more or less angular sand grain packings. Experiments were performed under uniaxial stress, which resulted in hexagonal (transversely isotropic) symmetry of the poroelastic response. One important conclusion from the general analysis is that the drained constants are uniquely related to the undrained constants, assuming that porosity, grain bulk modulus, and pore uid bulk modulus are already known. Since the resulting system of equations for all the drained constants is linear, measurement error in undrained constants also propagates linearly into the computed drained constants.
A natural cosmological constant from chameleons
Horatiu Nastase; Amanda Weltman
2015-04-06T23:59:59.000Z
We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru-Kallosh-Linde-Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why $\\Lambda$ is so small, yet nonzero) and the coincidence problem (why $\\Lambda$ is comparable to the matter density now).
Vacuum Energy and the Cosmological Constant
A. C. Melissinos
2001-12-19T23:59:59.000Z
We discuss a numerical relation between the cosmological constant and the vacuum energy arising from the Casimir effect in extra dimensions
Burke, Peter
energy flow, choose carbohydrates from intact grains such as whole grain bread, brown rice, and oats disease, and diabetes. Good nutrition also plays an important role in enhancing your energy, stamina a pear (see Body Mass Index [BMI] chart, page 4). It may be challenging to stay faithful to a sensible
Sequential Constant Size Compressors for Reinforcement Learning
Schmidhuber, Juergen
Sequential Constant Size Compressors for Reinforcement Learning Linus GisslÂ´en, Matt Luciw, Vincent with this problem: standard RL techniques using as input the hidden layer output of a Sequential Constant-Size Compressor (SCSC). The SCSC takes the form of a sequential Recurrent Auto-Associative Mem- ory, trained
Newtonian Constant of Gravitation International Consortium
Newtonian Constant of Gravitation International Consortium I. BACKGROUND Recent measurements of the Newtonian constant of gravitation G are in disagreement, with discrepancies that are roughly ten times forces on a laboratory scale. It also raises the question of whether the Newtonian force law
Vacuum Fluctuations and the Cosmological Constant
Shi Qi
2006-04-29T23:59:59.000Z
The hypothesis is proposed that under the approximation that the quantum equations of motion reduce to the classical ones, the quantum vacuum also reduces to the classical vacuum--the empty space. The vacuum energy of QED is studied under this hypothesis. A possible solution to the cosmological constant problem is provided and a kind of parameterization of the cosmological "constant" is derived.
Lovley, Derek
Planetsave Like this post? Subscribe to our RSS feed and stay up to date. Navy Develops Battery that Runs on Mud (http://planetsave.com/blog/2010/04/20/navy-develops-battery-that-runs-on- mud/) (http by Joshua S Hill Published on April 20th, 2010 in Energy & Fuel 1 Comment 5/4/2010 Navy Develops Battery
Kunkle, Tom
IN AN EMERGENCY, CALL PUBLIC SAFETY AT 843.953.5611 Stay informed. Be prepared. Visit emergency instructions from emergency personnel · Do not use elevators. · Take personal belongings (ID, keys, purses authorized to do so by emergency personnel. FIRES · Activate the nearest fire alarm pull station. · Call
Bubble Universes With Different Gravitational Constants
Yu-ichi Takamizu; Kei-ichi Maeda
2015-04-21T23:59:59.000Z
We argue a scenario motivated by the context of string landscape, where our universe is produced by a new vacuum bubble embedded in an old bubble and these bubble universes have not only different cosmological constants, but also their own different gravitational constants. We study these effects on the primordial curvature perturbations. In order to construct a model of varying gravitational constants, we use the Jordan-Brans-Dicke (JBD) theory where different expectation values of scalar fields produce difference of constants. In this system, we investigate the nucleation of bubble universe and dynamics of the wall separating two spacetimes. In particular, the primordial curvature perturbation on superhorizon scales can be affected by the wall trajectory as the boundary effect. We show the effect of gravitational constant in the exterior bubble universe can provide a peak like a bump feature at a large scale in a modulation of power spectrum.
Bubble Universes With Different Gravitational Constants
Takamizu, Yu-ichi
2015-01-01T23:59:59.000Z
We argue a scenario motivated by the context of string landscape, where our universe is produced by a new vacuum bubble embedded in an old bubble and these bubble universes have not only different cosmological constants, but also their own different gravitational constants. We study these effects on the primordial curvature perturbations. In order to construct a model of varying gravitational constants, we use the Jordan-Brans-Dicke (JBD) theory where different expectation values of scalar fields produce difference of constants. In this system, we investigate the nucleation of bubble universe and dynamics of the wall separating two spacetimes. In particular, the primordial curvature perturbation on superhorizon scales can be affected by the wall trajectory as the boundary effect. We show the effect of gravitational constant in the exterior bubble universe can provide a peak like a bump feature at a large scale in a modulation of power spectrum.
Constants and Pseudo-Constants of Coupled Beam Motion in the PEP-II Rings
Decker, F.J.; Colocho, W.S.; Wang, M.H.; Yan, Y.T.; Yocky, G.; /SLAC
2011-11-01T23:59:59.000Z
Constants of beam motion help as cross checks to analyze beam diagnostics and the modeling procedure. Pseudo-constants, like the betatron mismatch parameter or the coupling parameter det C, are constant till certain elements in the beam line change them. This can be used to visually find the non-desired changes, pinpointing errors compared with the model.
The Meaning Of The Fine Structure Constant
R. L. Oldershaw
2009-02-21T23:59:59.000Z
A possible explanation is offered for the longstanding mystery surrounding the meaning of the fine structure constant. The reasoning is based on a discrete self-similar cosmological paradigm that has shown promise in explaining the general scaling properties of nature's global hierarchy. The discrete scale invariance of the paradigm implies that "strong gravity" governs gravitational interactions within atomic scale systems. Given the revised gravitational coupling constant and Planck mass, one can demonstrate that the fine structure constant is the ratio of the strengths of the unit electromagnetic interaction and the unit gravitational interaction within atomic scale systems. [Abridged
A Nuclear Data Approach for the Hubble Constant Measurements
Pritychenko, B
2015-01-01T23:59:59.000Z
An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP) codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.00(770) (km/sec)/Mpc. This recommended value is based on the last 25 years of experimental research and includes contributions from different types of measurements. The present result implies (14.6$\\pm$1.7)$\\times$10$^{9}$ years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.
Asymptotically Vanishing Cosmological Constant in the Multiverse
Hikaru Kawai; Takashi Okada
2011-04-21T23:59:59.000Z
We study the problem of the cosmological constant in the context of the multiverse in Lorentzian spacetime, and show that the cosmological constant will vanish in the future. This sort of argument was started from Coleman in 1989, and he argued that the Euclidean wormholes make the multiverse partition a superposition of various values of the cosmological constant $\\Lambda$, which has a sharp peak at $\\Lambda=0$. However, the implication of the Euclidean analysis to our Lorentzian spacetime is unclear. With this motivation, we analyze the quantum state of the multiverse in Lorentzian spacetime by the WKB method, and calculate the density matrix of our universe by tracing out the other universes. Our result predicts vanishing cosmological constant. While Coleman obtained the enhancement at $\\Lambda=0$ through the action itself, in our Lorentzian analysis the similar enhancement arises from the front factor of $e^{iS}$ in the universe wave function, which is in the next leading order in the WKB approximation.
Cosmological constant in scale-invariant theories
Foot, Robert; Kobakhidze, Archil; Volkas, Raymond R. [School of Physics, University of Melbourne, Victoria 3010 (Australia)
2011-10-01T23:59:59.000Z
The incorporation of a small cosmological constant within radiatively broken scale-invariant models is discussed. We show that phenomenologically consistent scale-invariant models can be constructed which allow a small positive cosmological constant, providing certain relation between the particle masses is satisfied. As a result, the mass of the dilaton is generated at two-loop level. Another interesting consequence is that the electroweak symmetry-breaking vacuum in such models is necessarily a metastable ''false'' vacuum which, fortunately, is not expected to decay on cosmological time scales.
Electromagnetic corrections to pseudoscalar decay constants
Benjamin Glaessle; Gunnar S. Bali
2011-11-16T23:59:59.000Z
The effects of electromagnetic interactions on pseudoscalar decay constants are investigated. Using a compact QED and QCD action we are able to resolve differences of about 0.1 MeV. We obtain the preliminary results f_pi^0-f_pi^+/- =0.09(3) MeV and f_D^0-f_D^+/- =0.79(11) MeV for light and charmed pseudoscalar decay constants on a N_f=2 nonperturbatively improved Sheikholeslami-Wohlert ensemble.
The Vacuum and the Cosmological Constant Problem
Gerald E. Marsh
2008-06-20T23:59:59.000Z
It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the vacuum polarization tensor--must be eliminated either explicitly or by some form of regularization followed by renormalization. It has recently been shown that lack of gauge invariance is a result of the way the vacuum is defined, and redefining the vacuum so that the theory is gauge invariant may also offer a solution to the cosmological constant problem.
Environmental Dependence of Masses and Coupling Constants
Keith A. Olive; Maxim Pospelov
2008-01-04T23:59:59.000Z
We construct a class of scalar field models coupled to matter that lead to the dependence of masses and coupling constants on the ambient matter density. Such models predict a deviation of couplings measured on the Earth from values determined in low-density astrophysical environments, but do not necessarily require the evolution of coupling constants with the redshift in the recent cosmological past. Additional laboratory and astrophysical tests of \\Delta \\alpha and \\Delta(m_p/m_e) as functions of the ambient matter density are warranted.
Matyushov, Dmitry
Thermodynamics and dynamics of a monoatomic glass former. Constant pressure and constant volume-pressure simulations of the thermodynamic and dynamic properties of the low-temperature liquid and crystalline phases the thermodynamics of the configurational manifold as an ensemble of excitations, each carrying an excitation entropy
Constant-Pressure Measurement of Steam-
Stanford University
SGP-TR-169 Constant-Pressure Measurement of Steam- Water Relative Permeability Peter A. O by measuring in-situ steam saturation more directly. Mobile steam mass fraction was established by separate steam and water inlets or by correlating with previous results. The measured steam-water relative
Vacuum Fluctuations Cannot Mimic a Cosmological Constant
Robert D. Klauber
2007-11-05T23:59:59.000Z
When the vacuum fluctuation pressure is calculated directly from fundamental principles of quantum field theory, in the same manner as vacuum fluctuation energy density is commonly calculated, one finds it is not equal to the negative of the vacuum fluctuation energy density. Thus, vacuum fluctuations cannot manifest as a cosmological constant of any order.
High Dielectric Constant Capacitors for Power Electronic Systems...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Dielectric Constant Capacitors for Power Electronic Systems High Dielectric Constant Capacitors for Power Electronic Systems 2009 DOE Hydrogen Program and Vehicle Technologies...
High Dialectric Constant Capacitors for Power Electronic Systems...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
High Dialectric Constant Capacitors for Power Electronic Systems High Dialectric Constant Capacitors for Power Electronic Systems 2012 DOE Hydrogen and Fuel Cells Program and...
High-Dialectric-Constant Capacitors for Power Electronic Systems...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
High-Dialectric-Constant Capacitors for Power Electronic Systems High-Dialectric-Constant Capacitors for Power Electronic Systems 2011 DOE Hydrogen and Fuel Cells Program, and...
High Dialectric Constant Capacitors for Power Electronic Systems...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Dialectric Constant Capacitors for Power Electronic Systems High Dialectric Constant Capacitors for Power Electronic Systems 2010 DOE Vehicle Technologies and Hydrogen Programs...
Cosmological constant and quantum gravitational corrections to the running fine structure constant
David J. Toms
2008-09-23T23:59:59.000Z
The quantum gravitational contribution to the renormalization group behavior of the electric charge in Einstein-Maxwell theory with a cosmological constant is considered. Quantum gravity is shown to lead to a contribution to the running charge not present when the cosmological constant vanishes. This re-opens the possibility, suggested by Robinson and Wilczek, of altering the scaling behaviour of gauge theories at high energies although our result differs. We show the possibility of an ultraviolet fixed point that is linked directly to the cosmological constant.
Variable energy constant current accelerator structure
Anderson, O.A.
1988-07-13T23:59:59.000Z
A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90/degree/ intervals with opposing electrodes maintained at the same potential. 12 figs., 3 tabs.
The Cosmological Constant in the Quantum Multiverse
Grant Larsen; Yasunori Nomura; H. L. L. Roberts
2011-12-14T23:59:59.000Z
Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. In this paper we elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein.
Light Dragging, the Origin of Hubble's Constant
Walter J. Christensen Jr
2008-10-07T23:59:59.000Z
Recently E. Harrison has argued the Red Shift distance law proposed by Hubble and velocity-distance law developed later on theoretical grounds has no general proof demonstrating the two laws are actually equivalent. It is the purpose of this paper to account for the nebular redshift law of Hubble based on two principles: 1) Spacetime motion and light dragging. 2) An overall spacetime index of refraction based on Hubble's Constant.
Comment on "Black holes constrain varying constants"
V. V. Flambaum
2002-08-20T23:59:59.000Z
A recent paper [DDL] claims that the increase of the proton electric charge e leads to a (forbidden) decrease of black hole entropy, therefore, possible evidence for variation of $\\alpha=e^2/\\hbar c$ [alpha] must be interpreted as a decrease of the speed of light. We argue that purely theoretical consideration of black holes possibly cannot give any model-independent limitations on variation of fundamental constants.
Which Fundamental Constants for CMB and BAO?
Rich, James
2015-01-01T23:59:59.000Z
We study the Cosmic Microwave Background using the three-scale framework of Hu et al. to derive the dependence of the CMB temperature anisotropy spectrum on the fundamental constants. We show that, as expected, the observed spectrum depends only on \\emph{dimensionless} combinations of the constants, and we emphasize the points that make this generally true for cosmological observations. Our analysis suggests that the CMB spectrum shape is mostly determined by $\\alpha^2m_e/m_p$ and the proton-CDM-particle mass ratio, $m_p/\\mchi$, with a sub-dominant dependence on $(G\\mchi m_e/\\hbar c)\\alpha^\\beta$ with $\\beta\\sim -7$. The distance to the last-scattering surface depends on $Gm_p\\mchi/\\hbar c$, so published CMB observational limits on time variations of the constants, besides making assumptions about the form of the dark-energy, implicitly assume the time-independence of this quantity. On the other hand, low-redshift $H_0$, BAO and large-scale structure data can be combined with the \\emph{shape} of the CMB spect...
Can Compactifications Solve the Cosmological Constant Problem?
Hertzberg, Mark P
2015-01-01T23:59:59.000Z
Recently, there have been claims in the literature that the cosmological constant problem can be dynamically solved by specific compactifications of gravity from higher-dimensional toy models. These models have the novel feature that in the four-dimensional theory, the cosmological constant $\\Lambda$ is much smaller than the Planck density and in fact accumulates at $\\Lambda=0$. Here we show that while these are very interesting models, they do not properly address the real cosmological constant problem. As we explain, the real problem is not simply to obtain $\\Lambda$ that is small in Planck units in a toy model, but to explain why $\\Lambda$ is much smaller than other mass scales (and combinations of scales) in the theory. Instead, in these toy models, all other particle mass scales have been either removed or sent to zero, thus ignoring the real problem. To this end, we provide a general argument that the included moduli masses are generically of order Hubble, so sending them to zero trivially sends the cos...
Computing the dielectric constant of liquid water at constant dielectric displacement
Zhang, Chao
2015-01-01T23:59:59.000Z
The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement D. The method to constrain the electric displacement is the finite temperature classical variant of the constant-D method developed by Stengel, Spaldin and Vanderbilt (Nat. Phys. 2009, 5: 304). There is also a modification of this scheme imposing fixed values of the macroscopic field E. The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at D = 0 and E = 0 and two from the variation of polarization with finite D and E. It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies however, with constant D calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polar...
Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)] [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)
2014-01-21T23:59:59.000Z
Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.
From constant to non-degenerately vanishing magnetic fields in superconductivity
Bernard Helffer; Ayman Kachmar
2015-03-30T23:59:59.000Z
We explore the relationship between two reference functions arising in the analysis of the Ginzburg-Landau functional. The first function describes the distribution of superconductivity in a type II superconductor subjected to a constant magnetic field. The second function describes the distribution of superconductivity in a type II superconductor submitted to a variable magnetic field that vanishes non-degenerately along a smooth curve.
Self-gravitating scalar breathers with negative cosmological constant
Gyula Fodor; Péter Forgács; Philippe Grandclément
2015-07-10T23:59:59.000Z
Breather-type (time-periodic and spatially localized) solutions with spherical symmetry are investigated in a massless scalar field theory coupled to Einstein's gravity with cosmological constant in $d$ spatial dimensions imposing anti de Sitter (AdS) asymptotics on space-time. Using a code constructed with the Kadath library that enables the use of spectral methods, the phase space of breather solutions is explored in detail for $d=3$ and $d=4$. It is found that there are discrete families of solutions indexed by an integer and by their frequency. Using a time evolution code these AdS breathers are found to be stable for up to a critical central density, in analogy to boson stars. Using an analytical perturbative expansion small amplitude breathers are worked out for arbitrary dimensions $d$.
On the local variation of the Hubble constant
Odderskov, Io; Hannestad, Steen [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Haugbølle, Troels, E-mail: isho07@phys.au.dk, E-mail: sth@phys.au.dk, E-mail: troels.haugboelle@snm.ku.dk [Centre for Star and Planet Formation, Natural History Museum of Denmark and Niels Bohr Institute University of Copenhagen, DK-1350 Copenhagen (Denmark)
2014-10-01T23:59:59.000Z
We have carefully studied how local measurements of the Hubble constant, H{sub 0}, can be influenced by a variety of different parameters related to survey depth, size, and fraction of the sky observed, as well as observer position in space. Our study is based on N-body simulations of structure in the standard ?CDM model and our conclusion is that the expected variance in measurements of H{sub 0} is far too small to explain the current discrepancy between the low value of H{sub 0} inferred from measurements of the cosmic microwave background (CMB) by the Planck collaboration and the value measured directly in the local universe by use of Type Ia supernovae. This conclusion is very robust and does not change with different assumptions about effective sky coverage and depth of the survey or observer position in space.
Seismic pulse propagation with constant Q and stable probability distributions
Francesco Mainardi; Massimo Tomirotti
2010-08-07T23:59:59.000Z
The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type) in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with index of stability determined by the order of the fractional time derivative in the evolution equation.
Fine-structure constant constraints on dark energy
Martins, C J A P
2015-01-01T23:59:59.000Z
We use astrophysical and atomic clock tests of the stability of the fine-structure constant $\\alpha$, together with Type Ia supernova and Hubble parameter data, to constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling, $\\zeta$, to the electromagnetic sector) the $\\alpha$ variation. We show how current data tightly constrains a combination of $\\zeta$ and the dark energy equation of state $w_0$. At the $95\\%$ confidence level and marginalizing over $w_0$ we find $|\\zeta|<5\\times10^{-6}$, with the atomic clock tests dominating the constraints. The forthcoming generation of high-resolution ultra-stable spectrographs will enable significantly tighter constraints.
Low Energy Constants from the zero mode contribution to the pseudo-scalar correlator
S. Shcheredin; W. Bietenholz
2005-08-31T23:59:59.000Z
We apply different types of overlap operators in quenched QCD simulations to compute the zero mode contribution to the pseudo-scalar correlator. In particular we use the conventional Neuberger Dirac operator and the overlap hypercube Dirac operator. Confronting our data with the analytical predictions by Chiral Perturbation Theory we evaluate the pion decay constant and the parameter \\alpha of the quenched chiral Lagrangian.
Stability of adhesion clusters under constant force
T. Erdmann; U. S. Schwarz
2004-01-27T23:59:59.000Z
We solve the stochastic equations for a cluster of parallel bonds with shared constant loading, rebinding and the completely dissociated state as an absorbing boundary. In the small force regime, cluster lifetime grows only logarithmically with bond number for weak rebinding, but exponentially for strong rebinding. Therefore rebinding is essential to ensure physiological lifetimes. The number of bonds decays exponentially with time for most cases, but in the intermediate force regime, a small increase in loading can lead to much faster decay. This effect might be used by cell-matrix adhesions to induce signaling events through cytoskeletal loading.
A Measurement of Newton's Gravitational Constant
St. Schlamminger; E. Holzschuh; W. Kündig; F. Nolting; R. E. Pixley; J. Schurr; U. Straumann
2006-09-07T23:59:59.000Z
A precision measurement of the gravitational constant $G$ has been made using a beam balance. Special attention has been given to determining the calibration, the effect of a possible nonlinearity of the balance and the zero-point variation of the balance. The equipment, the measurements and the analysis are described in detail. The value obtained for G is 6.674252(109)(54) 10^{-11} m3 kg-1 s-2. The relative statistical and systematic uncertainties of this result are 16.3 10^{-6} and 8.1 10^{-6}, respectively.
Constant Volume During Combustion | Department of Energy
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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 Center Home Page on Delicious RankShale_Gas.pdfService on theFossilAction No.Complete StreetsEngines |Ms. M. P. DelozierConstant Volume
TASI Lectures on the cosmological constant
Bousso, Raphael; Bousso, Raphael
2007-08-30T23:59:59.000Z
The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant over large spacetime regions. This can explain the observed value, but only in a theory satisfying a number of restrictive kinematic and dynamical conditions. String theory offers a concrete realization through its landscape of metastable vacua.
Variable energy constant current accelerator structure
Anderson, Oscar A. (Berkeley, CA)
1990-01-01T23:59:59.000Z
A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90.degree. intervals with opposing electrodes maintained at the same potential. Adjacent cylinder electrodes of the quadrupole structure are maintained at different potentials to thereby reshape the cross section of the charged particle beam to an ellipse in cross section at the mid point along each quadrupole electrode unit in the accelerator modules. The beam is maintained in focus by alternating the major axis of the ellipse along the x and y axis respectively at adjacent quadrupoles. In another embodiment, electrostatic ring electrodes may be utilized instead of the quadrupole electrodes.
Constant-mesh, multiple-shaft transmission
Rea, J.E.; Mills, D.D.; Sewell, J.S.
1992-04-21T23:59:59.000Z
This patent describes a multiple-shaft, constant-mesh transmission adapted to establish selectively a reverse torque delivery path and a forward drive torque delivery path and having a torque input means including a torque input shaft, a mainshaft aligned with the input shaft, a countershaft geared to the input shaft in spaced, parallel relationship with respect to the mainshaft, a torque output shaft joined to the mainshaft; multiple mainshaft gear elements journalled on the main airshaft, multiple cluster gear elements carried by the countershaft in meshing engagement with the mainshaft gear elements, one of the cluster gear elements being rotatably journalled on the countershaft; a reverse idle gear, a reverse gear journalled on the countershaft, the reverse idler gear being in constant mesh with the reverse gear and one of the mainshaft gear elements; first clutch means for connecting selectively the reverse gear and the countershaft; second synchronizer clutch means for connecting selectively the one of the mainshaft gear elements to the mainshaft; and third synchronizer clutch means for selectively connecting another of the mainshaft gear elements to the mainshaft; the first clutch means being a double-acting clutch with a first common axially movable clutch element adapted upon movement in one axial direction to drivably connected the reverse gear to the countershaft and adapted upon movement in the opposite axial direction to connect the one cluster gear element to the countershaft.
CMB constraints on the fine structure constant
Kazuhide Ichikawa; Toru Kanzaki; Masahiro Kawasaki
2006-05-25T23:59:59.000Z
We study constraints on time variation of the fine structure constant alpha from cosmic microwave background (CMB) taking into account simultaneous change in alpha and the electron mass m_e which might be implied in unification theories. We obtain the constraints -0.097 < Delta alpha/alpha < 0.034 at 95% C.L. using WMAP data only, and -0.042 < Delta alpha/alpha < 0.026 combining with the constraint on the Hubble parameter by the HST Hubble Key Project. These are improved by 15% compared with constraints assuming only alpha varies. We discuss other relations between variations in alpha and m_e but we do not find evidence for varying alpha.
Dimensionless constants, cosmology and other dark matters
Max Tegmark; Anthony Aguirre; Martin J Rees; Frank Wilczek
2006-01-11T23:59:59.000Z
We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin. Axion cosmology provides an instructive example, in which these two kinds of arguments must both be taken into account, and work well together. If a Peccei-Quinn phase transition occurred before or during inflation, then the axion dark matter density will vary from place to place with a probability distribution. By calculating the net dark matter halo formation rate as a function of all four relevant cosmological parameters and assessing other constraints, we find that this probability distribution, computed at stable solar systems, is arguably peaked near the observed dark matter density. If cosmologically relevant WIMP dark matter is discovered, then one naturally expects comparable densities of WIMPs and axions, making it important to follow up with precision measurements to determine whether WIMPs account for all of the dark matter or merely part of it.
The variation of the fine structure constant: testing the dipole model with thermonuclear supernovae
Kraiselburd, Lucila; Negrelli, Carolina; Berro, Enrique García
2014-01-01T23:59:59.000Z
The large-number hypothesis conjectures that fundamental constants may vary. Accordingly, the spacetime variation of fundamental constants has been an active subject of research for decades. Recently, using data obtained with large telescopes a phenomenological model in which the fine structure constant might vary spatially has been proposed. We test whether this hypothetical spatial variation of {\\alpha}, which follows a dipole law, is compatible with the data of distant thermonuclear supernovae. Unlike previous works, in our calculations we consider not only the variation of the luminosity distance when a varying {\\alpha} is adopted, but we also take into account the variation of the peak luminosity of Type Ia supernovae resulting from a variation of {\\alpha}. This is done using an empirical relation for the peak bolometric magnitude of thermonuclear supernovae that correctly reproduces the results of detailed numerical simulations. We find that there is no significant difference between the several phenome...
Curvature invariants in type-III spacetimes
V. Pravda
1999-08-17T23:59:59.000Z
The results of paper [1] are generalized for vacuum type-III solutions with, in general, a non-vanishing cosmological constant Lambda. It is shown that all curvature invariants containing derivatives of the Weyl tensor vanish if a type-III spacetime admits a non-expanding and non-twisting null geodesic congruence. A non-vanishing curvature invariant containing first derivatives of the Weyl tensor is found in the case of type-III spacetime with expansion or twist.
Cosmic explosions, life in the Universe and the Cosmological Constant
Piran, Tsvi; Cuesta, Antonio J; Simpson, Fergus; Verde, Licia
2015-01-01T23:59:59.000Z
Galactic Gamma-Ray Bursts (GRBs) are copious sources of gamma-rays that can pose a threat to complex life. Using recent determinations of their rate and the probability of GRBs causing massive extinction, we explore what type of universes are most likely to harbour advanced forms of life. For this purpose we use cosmological N-body simulations to determine at what time and for what value of the cosmological constant ($\\Lambda$) the chances of life being unaffected by cosmic explosions are maximised. We find that $\\Lambda-$dominated universes favour the survival of life against GRBs. Within a $\\Lambda$CDM cosmology, the parameters that govern the likelihood of life survival to GRBs are dictated by the value of $\\Lambda$ and the age of the Universe. We find that we seem to live in a favorable point in this parameter phase space which minimises the exposure to cosmic explosions, yet maximises the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.
Hacker, Randi; Tsutsui, William
2007-03-14T23:59:59.000Z
Sox spent a hundred mil to acquire pitcher Daisuke Matsuzaka; they probably weren't even aware that he is a Type O and that they make the best bankers, politicians and... you guessed it... professional baseball players. #ceas #hacker #japan #tsutsuien...
Initial data sets with ends of cylindrical type: I. The Lichnerowicz equation
Piotr T. Chru?ciel; Rafe Mazzeo
2014-10-07T23:59:59.000Z
We construct large classes of vacuum general relativistic initial data sets, possibly with a cosmological constant Lambda, containing ends of cylindrical type.
Experimental determination of the effective strong coupling constant
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2005-09-15T23:59:59.000Z
We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Flavor dependence of normalization constant for an infrared renormalon
Taekoon Lee
2015-02-09T23:59:59.000Z
An ansatz is proposed for the flavor dependence of the normalization constant for the first IR renormalon in heavy quark pole mass.
Energy Science and Technology Software Center (OSTI)
002851IBMPC00 STAYSL PNNL Suite http://radiochemscieng.pnnl.gov/research_areas/research_area_description.asp?id=283
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS
Zucker, Robert S.
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS AND NEURONS WILFRID RALL From electrophysiological experiments. It depends upon the several time con- stants present in passive decay of membrane membrane time constant, Tm = RmCm, observed in the decay of a uniform membrane potential, there exist many
Equilibrium surface distributions for constant energy ensembles B. I. Henry
Henry, Bruce Ian
Equilibrium surface distributions for constant energy ensembles B. I. Henry Department of Applied distributions are seen [11,12]. In this paper we shall discuss how one calculates the constant energy energy en semble are discussed. An equilibrium surface density is introduced and used to calculate
Applications of nonlocal constants of motion in Lagrangian Dynamics
Gianluca Gorni; Gaetano Zampieri
2015-01-29T23:59:59.000Z
We give a recipe to generate "nonlocal" constants of motion for ODE Lagrangian systems and we apply the method to find useful constants of motion for dissipative system, for the Lane-Emden equation, and for the Maxwell-Bloch system with RWA.
The Duffing Oscillator And Linearization Techniques For Its Motion Constants
Rashdan, Mouath
2014-01-16T23:59:59.000Z
constant is known, solving the system is no longer needed to analyze the characteristics of the system. Motion constants are time independent integrals that are hard to find for nonlinear dynamic systems. We chose the Duffing Oscillator as a higher order...
Cosmological model with $?_M$-dependent cosmological constant
V. Majernik
2003-10-21T23:59:59.000Z
The idea here is to set the cosmical constant $\\lambda$ proportional to the scalar of the stress-energy tensor of the ordinary matter. We investigate the evolution of the scale factor in a cosmological model in which the cosmological constant is proportional to the scalar of the stress-energy tensor.
The Duffing Oscillator And Linearization Techniques For Its Motion Constants
Rashdan, Mouath
2014-01-16T23:59:59.000Z
constant is known, solving the system is no longer needed to analyze the characteristics of the system. Motion constants are time independent integrals that are hard to find for nonlinear dynamic systems. We chose the Duffing Oscillator as a higher order...
Evolving Lorentzian wormholes supported by phantom matter and cosmological constant
Mauricio Cataldo; Sergio del Campo; Paul Minning; Patricio Salgado
2008-12-23T23:59:59.000Z
In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made of phantom energy in the presence of a cosmological constant. We derive analytical evolving wormhole geometries by supposing that the radial tension of the phantom matter, which is negative to the radial pressure, and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. In this case the presence of a cosmological constant ensures accelerated expansion of the wormhole configurations. More specifically, for positive cosmological constant we have wormholes which expand forever and, for negative cosmological constant we have wormholes which expand to a maximum value and then recolapse. At spatial infinity the energy density and the pressures of the anisotropic phantom matter threading the wormholes vanish; thus these evolving wormholes are asymptotically vacuum $\\Lambda$-Friedmann models with either open or closed or flat topologies.
Lovley, Derek
|Archives| Charts| Companies/Links| Conferences| How A Fuel Cell Works | Patents| | Types of Fuel Cells | The Basics | Fuel Cell News | Basics on Hydrogen | Search| *Stay Updated every week With a Free Subscription To "Inside The Industry"As Well as a Weekly Updated Patents Page Fuel cell power Publication Date
Lovley, Derek
|Archives| Charts| Companies/Links| Conferences| How A Fuel Cell Works | Patents| | Types of Fuel Cells | The Basics | Fuel Cell News | Basics on Hydrogen | Search| *Stay Updated every week With a Free Subscription To "Inside The Industry"As Well as a Weekly Updated Patents Page Gulliver's fuel cell travels
Methodology for extracting local constants from petroleum cracking flows
Chang, Shen-Lin (Woodridge, IL); Lottes, Steven A. (Naperville, IL); Zhou, Chenn Q. (Munster, IN)
2000-01-01T23:59:59.000Z
A methodology provides for the extraction of local chemical kinetic model constants for use in a reacting flow computational fluid dynamics (CFD) computer code with chemical kinetic computations to optimize the operating conditions or design of the system, including retrofit design improvements to existing systems. The coupled CFD and kinetic computer code are used in combination with data obtained from a matrix of experimental tests to extract the kinetic constants. Local fluid dynamic effects are implicitly included in the extracted local kinetic constants for each particular application system to which the methodology is applied. The extracted local kinetic model constants work well over a fairly broad range of operating conditions for specific and complex reaction sets in specific and complex reactor systems. While disclosed in terms of use in a Fluid Catalytic Cracking (FCC) riser, the inventive methodology has application in virtually any reaction set to extract constants for any particular application and reaction set formulation. The methodology includes the step of: (1) selecting the test data sets for various conditions; (2) establishing the general trend of the parametric effect on the measured product yields; (3) calculating product yields for the selected test conditions using coupled computational fluid dynamics and chemical kinetics; (4) adjusting the local kinetic constants to match calculated product yields with experimental data; and (5) validating the determined set of local kinetic constants by comparing the calculated results with experimental data from additional test runs at different operating conditions.
Experimental determination of the effective strong coupling constant
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2007-07-01T23:59:59.000Z
We extract an effective strong coupling constant from low Q{sup 2} data on the Bjorken sum. Using sum rules, we establish its Q{sup 2}-behavior over the complete Q{sup 2}-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
EVALUATION OF CONSTANT CURRENT WELD CONTROL FOR PINCH WELDING
Korinko, P; STANLEY, S; HOWARD, H
2005-10-11T23:59:59.000Z
Modern weld controllers typically use current to control the weld process. SRS uses a legacy voltage control method. This task was undertaken to determine if the improvements in the weld control equipment could be implemented to provide improvements to the process control. The constant current mode of operation will reduce weld variability by about a factor of 4. The constant voltage welds were slightly hotter than the constant current welds of the same nominal current. The control mode did not appear to adversely affect the weld quality, but appropriate current ranges need to be established and a qualification methodology for both welding and shunt calibrations needs to be developed and documented.
Compactifications of F-Theory on Calabi-Yau Threefolds at Constant Coupli ng
Changhyun Ahn; Soonkeon Nam
1997-03-03T23:59:59.000Z
Generalizing the work of Sen, we analyze special points in the moduli space of the compactification of the F-theory on elliptically fibered Calabi-Yau threefolds where the coupling remains constant. These contain points where they can be realized as orbifolds of six torus $T^6$ by $Z_m \\times Z_n (m, n=2, 3, 4, 6)$. At various types of intersection points of singularities, we find that the enhancement of gauge symmetries arises from the intersection of two kinds of singularities. We also argue that when we take the Hirzebruch surface as a base for the Calabi- Yau threefold, the condition for constant coupling corresponds to the case where the point like instantons coalesce, giving rise to enhanced gauge group of $Sp(k)$.
V. B. Bezerra; G. L. Klimchitskaya; V. M. Mostepanenko; C. Romero
2014-08-31T23:59:59.000Z
We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional force arising in the experimental configurations due to two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11eV and 8eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Eotvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from 10^{-10}eV to 20eV.
Van't Hoff law for temperature dependent Langmuir constants in clathrate hydrate nanocavities
Lakhlifi, Azzedine
2015-01-01T23:59:59.000Z
This work gives a van't Hoff law expression of Langmuir constants of different species for determining their occupancy in the nanocavities of clathrate hydrates. The van't Hoff law's parameters are derived from a fit with Langmuir constants calculated using a pairwise site-site interaction potential to model the anisotropic potential environment in the cavities, as a function of temperature. The parameters can be used for calculating clathrates compositions. Results are given for nineteen gas species trapped in the small and large cavities of structure types I and II [1]. The accuracy of this approach is based on a comparison with available experimental data for ethane and cyclo- propane clathrate hydrates. The numerical method applied in this work, was recently validated from a comparison with the spherical cell method based on analytical considerations [1
Calculation of the Dimer Equilibrium Constant of Heavy Water Saturated Vapor
L. A. Bulavin; S. V. Khrapatiy; V. N. Makhlaichuk
2015-03-13T23:59:59.000Z
Water is the most common substance on Earth.The discovery of heavy water and its further study have shown that the change of hydrogen for deuterium leads to the significant differences in their properties.The triple point temperature of heavy water is higher,at the same time the critical temperature is lower.Experimental values of the second virial coefficient of the EOS for the vapor of normal and heavy water differ at all temperatures.This fact can influence the values of the dimerization constant for the heavy water vapor.The equilibrium properties of the dimerization process are described with the methods of chemical thermodynamics.The chemical potentials for monomers (m) and dimers (d)are the functions of their concentrations.The interactions of monomer-dimer and dimer-dimer types are taken into account within the solution of equation for chemical potentials.The obtained expression for the dimerization constant contains the contributions of these types.The averaged potentials are modeled by the Sutherland potential.Theoretical values of the dimerization constant for the heavy water vapor at different temperatures are compared to those for normal water.We see the exceeding of the values for the heavy water at all temperatures.This fact is in good agreement with all experimental data that is available.The excess is related to the differences in the character of the heat excitations of the dimers of normal and heavy water,their rotational constants and energy of their vibrational excitations.Significant role is also played by the monomer-dimer and dimer-dimer interactions.
CODATA Recommended Values of the Fundamental Physical Constants: 1998*
of recommended values is available on the World Wide Web at physics.nist.gov/ constants. © 1999 American Institute of Physics and American Chemical Society. S0047-2689 00 00301-9 Key words: CODATA, conversion
High Temperature, Large Sample Volume, Constant Flow Magic Angle...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
High Temperature, Large Sample Volume, Constant Flow Magic Angle Spinning NMR Probe for a 11.7 T Magnetic Field for In Situ Catalytic Reaction Characterization Project start date:...
Specific heat at constant volume in the thermodynamic model
C. B. Das; S. Das Gupta; A. Z. Mekjian
2003-07-04T23:59:59.000Z
A thermodynamic model for multifragmentation which is frequently used appears to give very different values for specific heat at constant volume depending upon whether canonical or grand canonical ensemble is used. The cause for this discrepancy is analysed.
Optimization Online - Optimality gap of constant-order policies ...
Linwei Xin
2014-09-07T23:59:59.000Z
Sep 7, 2014 ... Optimality gap of constant-order policies decays exponentially in the lead time for ... For the special case of exponentially distributed demand, we further ... Category 1: Applications -- OR and Management Sciences (Supply ...
Cosmology models with ?_M-dependent cosmological constant
V. Majernik
2002-01-07T23:59:59.000Z
We investigate the evolution of the scale factor in a cosmological model in which the cosmological constant is given by the scalar arisen by the contraction of the stress-energy tensor.
Statistical Inference for Models with Intractable Normalizing Constants
Jin, Ick Hoon
2011-06-27T23:59:59.000Z
In this dissertation, we have proposed two new algorithms for statistical inference for models with intractable normalizing constants: the Monte Carlo Metropolis-Hastings algorithm and the Bayesian Stochastic Approximation Monte Carlo algorithm...
Constant displacement rate experiments and constitutive modeling of asphalt mixtures
Hariharakumar, Pradeep
2006-04-12T23:59:59.000Z
The focus of this dissertation is on constant displacment rate experiments on asphalt concrete and on developing continuum models in a general thermo-mechanical setting which will corroborate with the experimental results. Modeling asphalt concrete...
CODATA Recommended Values of the Fundamental Physical Constants: 2014
Mohr, Peter J; Taylor, Barry N
2015-01-01T23:59:59.000Z
This report gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. The recommended values may also be found on the World Wide Web at physics.nist.gov/constants.
Precision measurements of the Planck and Avogadro constants
Bettin, Horst; Man, John; Mana, Giovanni; Massa, Enrico; Picard, Alain
2013-01-01T23:59:59.000Z
Precision measurements of the fundamental constants are tour de force of basic metrology, where the useful information is usually beyond the last digit of the measured value. They challenge theoretical models and measurement technologies and set a network of measurement equations on which a universal system of units can be built, which stems from the most basic concepts of physics. Because of their connection with the mass unit, the Avogadro and Planck constants are on the spotlight.
STUDY TYPES What is a "Study Type"?
Dorf, Martin E.
#12;STUDY TYPES What is a "Study Type"? A Study Type is a defined business process. Study Types work together to streamline workflow, track data & keep users informed. There are 2 Study Types in eCOMS: COMS and IACUC. The COMS Study: The COMS Study is an online form that a Principal Investigator fills
CODATA recommended values of the fundamental physical constants: 2002
Mohr, Peter J.; Taylor, Barry N. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8401 (United States)
2005-01-01T23:59:59.000Z
This paper gives the 2002 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. Further, it describes in detail the adjustment of the values of the subset of constants on which the complete 2002 set of recommended values is based. Two noteworthy additions in the 2002 adjustment are recommended values for the bound-state rms charge radii of the proton and deuteron and tests of the exactness of the Josephson and quantum-Hall-effect relations K{sub J}=2e/h and R{sub K}=h/e{sup 2}, where K{sub J} and R{sub K} are the Josephson and von Klitzing constants, respectively, e is the elementary charge, and h is the Planck constant. The 2002 set replaces the previously recommended 1998 CODATA set. The 2002 adjustment takes into account the data considered in the 1998 adjustment as well as the data that became available between 31 December 1998, the closing date of that adjustment, and 31 December 2002, the closing date of the new adjustment. The differences between the 2002 and 1998 recommended values compared to the uncertainties of the latter are generally not unreasonable. The new CODATA set of recommended values may also be found on the World Wide Web at physics.nist.gov/constants.
Reaction Rate Constant for Radiative Association of CF$^+$
Öström, Jonatan; Nyman, Gunnar; Gustafsson, Magnus
2015-01-01T23:59:59.000Z
Reaction rate constants and cross sections are computed for the radiative association of carbon cations ($\\text{C}^+$) and fluorine atoms ($\\text{F}$) in their ground states. We consider reactions through the electronic transition $1^1\\Pi \\rightarrow X^1\\Sigma^+$ and rovibrational transitions on the $X^1\\Sigma^+$ and $a^3\\Pi$ potentials. Semiclassical and classical methods are used for the direct contribution and Breit--Wigner theory for the resonance contribution. Quantum mechanical perturbation theory is used for comparison. A modified formulation of the classical method applicable to permanent dipoles of unequally charged reactants is implemented. The total rate constant is fitted to the Arrhenius--Kooij formula in five temperature intervals with a relative difference of $10$ to $250\\:\\text{K}$, the rate constant is about $10^{-21}\\:\\text{cm}^3\\text{s}^{-1}$, rising toward $10^{-16}\\:\\text{cm}^3\\text{s}^{-1}$ fo...
Study of constant mode in charmonium correlators at finite temperature
Takashi Umeda
2007-10-01T23:59:59.000Z
Recent studies on the spectral function of charmonium in lattice QCD suggest survival of $J/\\psi$ state in the deconfinement phase till relatively high temperature. Based on the studies, different scenarios of $J/\\psi$ suppression are discussed to understand experimental results in the Heavy Ion Collision experiments. The scenarios require the information on the dissociation temperatures of $\\chi_c$ and $\\psi'$ as well as that of $J/\\psi$. In order to investigate these states in finite temperature lattice QCD, we have to consider an effect of a characteristic constant mode in the correlators. As a result of the study on the constant mode, we find that most drastic change in charmonium correlators for $\\chi_c$ states just above the deconfinement transition are caused by the constant mode. It may indicate the survival of $\\chi_c$ states after the deconfinement transition until, at least, $1.4T_c$.
Statistical theory of elastic constants of cholesteric liquid crystals
A. Kapanowski
2009-10-20T23:59:59.000Z
A statistical theory of cholesteric liquid crystals composed of short rigid biaxial molecules is presented. It is derived in the thermodynamic limit at a small density and a small twist. The uniaxial (biaxial) cholesteric phase is regarded as a distorted form of the uniaxial (biaxial) nematic phase. The chirality of the interactions and the implementation of the inversion to the rotation matrix elements are discussed in detail. General microscopic expressions for the elastic constants are derived. The expressions involve the one-particle distribution function and the potential energy of two-body short-range interactions. It is shown that the elastic constants determine the twist of the phase. The stability condition for the cholesteric and nematic phases is presented. The theory is used to study unary and binary systems. The temperature and concentration dependence of the order parameters, the elastic constants and the twist of the phase are obtained. The possibility of phase separation is not investigated.
Electromagnetic low-energy constants in ChPT
Christoph Haefeli; Mikhail A. Ivanov; Martin Schmid
2007-10-29T23:59:59.000Z
We investigate three-flavour chiral perturbation theory including virtual photons in a limit where the strange quark mass is much larger than the external momenta and the up and down quark masses, and where the external fields are those of two-flavour chiral perturbation theory. In particular we work out the strange quark mass dependence of the electromagnetic two-flavour low-energy constants C and k_i. We expect that these relations will be useful for a more precise determination of the electromagnetic low-energy constants.
Discrete canonical analysis of three dimensional gravity with cosmological constant
J. Berra-Montiel; J. E. Rosales-Quintero
2014-06-03T23:59:59.000Z
We discuss the interplay between standard canonical analysis and canonical discretization in three-dimensional gravity with cosmological constant. By using the Hamiltonian analysis, we find that the continuum local symmetries of the theory are given by the on-shell space-time diffeomorphisms, which at the action level, corresponds to the Kalb-Ramond transformations. At the time of discretization, although this symmetry is explicitly broken, we prove that the theory still preserves certain gauge freedom generated by a constant curvature relation in terms of holonomies and the Gauss's law in the lattice approach.
Period doubling, information entropy, and estimates for Feigenbaum's constants
Reginald D. Smith
2013-08-03T23:59:59.000Z
The relationship between period doubling bifurcations and Feigenbaum's constants has been studied for nearly 40 years and this relationship has helped uncover many fundamental aspects of universal scaling across multiple nonlinear dynamical systems. This paper will combine information entropy with symbolic dynamics to demonstrate how period doubling can be defined using these tools alone. In addition, the technique allows us to uncover some unexpected, simple estimates for Feigenbaum's constants which relate them to log 2 and the golden ratio, phi, as well as to each other.
Low-energy constants from ALEPH hadronic tau decay data
Boito, Diogo; Golterman, Maarten; Hudspith, Renwick; Lewis, Randy; Maltman, Kim; Peris, Santiago
2015-01-01T23:59:59.000Z
We determined the NLO chiral low-energy constant $L_{10}$, and various combinations of NNLO chiral low-energy constants employing recently revised ALEPH results for the non-strange vector (V) and axial-vector (A) hadronic tau decay distributions and recently updated RBC/UKQCD lattice data for the non-strange V-A two-point function. In this talk, we explain the ingredients of this determination. Our errors are at or below the level expected for contributions of yet higher order in the chiral expansion, suggesting that our results exhaust the possibilities of what can be meaningfully achieved in an NNLO analysis.
Low-Energy Constants from Resonance Chiral Theory
Antonio Pich
2008-12-14T23:59:59.000Z
I discuss the recent attempts to build an effective chiral Lagrangian incorporating massive resonance states. A useful approximation scheme to organize the resonance Lagrangian is provided by the large-Nc limit of QCD. Integrating out the resonance fields, one recovers the usual chiral perturbation theory Lagrangian with explicit values for the low-energy constants, parameterized in terms of resonance masses and couplings. The resonance chiral theory generates Green functions that interpolate between QCD and chiral perturbation theory. Analyzing these Green functions, both for large and small momenta, one gets QCD constraints on the resonance couplings and, therefore, information on the low-energy constants governing the Goldstone interactions.
Proposal for new experimental schemes to realize the Avogadro constant
Biraben, F; Clad, P; Genevs, G; Gournay, P; Guellati-Khlifa, S; Julien, L; Juncar, P; De Mirandes, E; Nez, F
2006-01-01T23:59:59.000Z
We propose two experimental schemes to determine and so to realize the Avogadro constant $N\\_{A}$ at the level of 10$^{-7}$ or better with a watt balance experiment and a cold atom experiment measuring $h/m(X)$ (where $h$ is the Planck constant and $m(X)$ the mass of the atom $X$). We give some prospects about achievable uncertainties and we discuss the opportunity to test the existence of possible unknown correction factors for the Josephson effect and quantum Hall effect.
The Equivalence Principle and the Constants of Nature
Thibault Damour
2009-06-17T23:59:59.000Z
We briefly review the various contexts within which one might address the issue of ``why'' the dimensionless constants of Nature have the particular values that they are observed to have. Both the general historical trend, in physics, of replacing a-priori-given, absolute structures by dynamical entities, and anthropic considerations, suggest that coupling ``constants'' have a dynamical nature. This hints at the existence of observable violations of the Equivalence Principle at some level, and motivates the need for improved tests of the Equivalence Principle.
Calculation of the Dimer Equilibrium Constant of Heavy Water Saturated Vapor
Bulavin, L A; Makhlaichuk, V N
2015-01-01T23:59:59.000Z
Water is the most common substance on Earth.The discovery of heavy water and its further study have shown that the change of hydrogen for deuterium leads to the significant differences in their properties.The triple point temperature of heavy water is higher,at the same time the critical temperature is lower.Experimental values of the second virial coefficient of the EOS for the vapor of normal and heavy water differ at all temperatures.This fact can influence the values of the dimerization constant for the heavy water vapor.The equilibrium properties of the dimerization process are described with the methods of chemical thermodynamics.The chemical potentials for monomers (m) and dimers (d)are the functions of their concentrations.The interactions of monomer-dimer and dimer-dimer types are taken into account within the solution of equation for chemical potentials.The obtained expression for the dimerization constant contains the contributions of these types.The averaged potentials are modeled by the Sutherlan...
University of Technology, Sydney
Assignment Types UTS LIBRARY February 2013 Academic Writing Guide Part 2 Assignment Types: This section outlines the basic types of written assignments, providing structural elements and examples. #12;2 II. Assignment Types 1. Essay Writing
A Constant Gain Kalman Filter Approach to track Maneuvering Targets
Naik, Naren
1 A Constant Gain Kalman Filter Approach to track Maneuvering Targets Ashwin Yadav1 , Peeyush domains. One of the most fundamental and widely used approaches to target tracking is the Kalman filter. In presence of unknown noise statistics there are difficulties in the Kalman filter yielding acceptable
Lower Bounds on Interactive Compressibility by Constant-Depth Circuits
Edinburgh, University of
Lower Bounds on Interactive Compressibility by Constant-Depth Circuits Arkadev Chattopadhyay to prove the first lower bounds on general probabilistic multi-round instance compression. We show, and strengthens results of Dubrov and Ishai [DI06]. We also show that a similar lower bound holds for Majority. We
Temperature and moisture dependence of dielectric constant for silica aerogels
Hrubesh, L.H., LLNL
1997-03-01T23:59:59.000Z
The dielectric constants of silica aerogels are among the lowest measured for any solid material. The silica aerogels also exhibit low thermal expansion and are thermally stable to temperatures exceeding 500{degrees}C. However, due to the open porosity and large surface areas for aerogels, their dielectric constants are strongly affected by moisture and temperature. This paper presents data for the dielectric constants of silica aerogels as a function of moisture content at 25{degrees}C, and as a function of temperature, for temperatures in the range from 25{degrees}C to 450{degrees}C. Dielectric constant data are also given for silica aerogels that are heat treated in dry nitrogen at 500{degrees}C, then cooled to 25{degrees}C for measurements in dry air. All measurements are made on bulk aerogel spheres at 22GHz microwave frequency, using a cavity perturbation method. The results of the dependence found here for bulk materials can be inferred to apply also to thin films of silica aerogels having similar nano-structures and densities.
Quartz resonators thermal modelization using located constants networks
Boyer, Edmond
of quartz resonator. The designed model is tested by comparison of the experimental frequency versus235 Quartz resonators thermal modelization using located constants networks S. Galliou and J. P modelization of quartz resonators is first presented ; next, the method consisting on establishing a located
Optical constants of carbon dioxide ice Stephen G. Warren
Warren, Stephen
Optical constants of carbon dioxide ice Stephen G. Warren Laboratory measurements of the absorption. At pressures belowthe triple point (5.2atm), carbon dioxide exists only as a gas or solid. The sublimation in the ultraviolet (50-130-nm wavelength) due to elec- tronic transitions. It is relatively transparent
Codes of constant Lee or Euclidean weight Jay A. Wood
Wood, Jay
Codes of constant Lee or Euclidean weight Jay A. Wood Department of Mathematics, Computer Science & Statistics Purdue University Calumet Hammond, Indiana 46323--2094 USA wood@calumet.purdue.edu http://www.calumet.purdue.edu/public/math/wood Scholarly Research Awards. #12; JAY A. WOOD 1. Linear codes as modules Throughout this extended abstract
DATA SUMMARIES The measured values of fundamental constants become more
Boal, David
that a mole contains 6.022 x 1023 atoms, a number referred to as Avogadro's number. The usefulness of the mole mass] 1.6750 x 10-27 kg kB [Boltzmann's constant] 1.38 x 10-23 J/Ko No [Avogadro's number] 6.022 x 1023
Two-component equations modelling water waves with constant vorticity
Joachim Escher; David Henry; Boris Kolev; Tony Lyons
2014-09-30T23:59:59.000Z
In this paper we derive a two-component system of nonlinear equations which model two-dimensional shallow water waves with constant vorticity. Then we prove well-posedness of this equation using a geometrical framework which allows us to recast this equation as a geodesic flow on an infinite dimensional manifold. Finally, we provide a criteria for global existence.
CODATA recommended values of the fundamental physical constants: 2010*
constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science. Theory of hydrogen and deuterium energy levels 1534 a. Dirac eigenvalue 1534 b. Relativistic recoil 1534 c. Nuclear polarizability 1535 d. Self energy 1535 e. Vacuum polarization 1536 f. Two
Constant Sustainable Consumption Rate in Optimal Growth with Exhaustible Resources*
Wan, Frederic Yui-Ming
's criterion of maximum sustainable consumption rate, previously formulated as a minimum-resource-extraction or not the constant unit resource extraction cost vanishes. The related problem of maximizing the terminal capital appetite for the earth's finite stock of nonrenew- able resources, such as fossil fuel and minerals, have
The Ds and D+ Leptonic Decay Constants from Lattice QCD
A. Bazavov; C. Bernard; C. DeTar; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. X. El-Khadra; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; M. Di Pierro; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
2009-12-28T23:59:59.000Z
We present the leptonic decay constants fDs and fD+ computed on the MILC collaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks with the Fermilab interpretation and improved staggered light quarks. The simultaneous chiral and continuum extrapolation, which determines both decay constants, includes partially-quenched lattice results at lattice spacings a ~ 0:09, 0:12 and 0:15 fm. We have made several recent improvements in our analysis: a) we include terms in the fit describing leading order heavy-quark discretization effects, b) we have adopted a more precise input r1 value consistent with our other D and B meson studies, c) we have retuned the input bare charm masses based upon the new r1. Our preliminary results are fDs = 260 +/-10 MeV and fD+ = 217 +/-10 MeV.
Spectral Properties and Dynamical Tunneling in Constant-Width Billiards
B. Dietz; T. Guhr; B. Gutkin; M. Miski-Oglu; A. Richter
2014-07-24T23:59:59.000Z
We determine with unprecedented accuracy the lowest 900 eigenvalues of two quantum constant-width billiards from resonance spectra measured with flat, superconducting microwave resonators. While the classical dynamics of the constant-width billiards is unidirectional, a change of the direction of motion is possible in the corresponding quantum system via dynamical tunneling. This becomes manifest in a splitting of the vast majority of resonances into doublets of nearly degenerate ones. The fluctuation properties of the two respective spectra are demonstrated to coincide with those of a random-matrix model for systems with violated time-reversal invariance and a mixed dynamics. Furthermore, we investigate tunneling in terms of the splittings of the doublet partners. On the basis of the random-matrix model we derive an analytical expression for the splitting distribution which is generally applicable to systems exhibiting dynamical tunneling between two regions with (predominantly) chaotic dynamics.
Constant-Optimized Quantum Circuits for Modular Multiplication and Exponentiation
Igor L. Markov; Mehdi Saeedi
2015-04-02T23:59:59.000Z
Reversible circuits for modular multiplication $Cx$%$M$ with $x
Sidestepping the Cosmological Constant with Football-Shaped Extra Dimensions
Sean M. Carroll; Monica M. Guica
2003-02-11T23:59:59.000Z
We present an exact solution for a factorizable brane-world spacetime with two extra dimensions and explicit brane sources. The compactification manifold has the topology of a two-sphere, and is stabilized by a bulk cosmological constant and magnetic flux. The geometry of the sphere is locally round except for conical singularities at the locations of two antipodal branes, deforming the sphere into an American-style football. The bulk magnetic flux needs to be fine-tuned to obtain flat geometry on the branes. Once this is done, the brane geometry is insensitive to the brane vacuum energy, which only affects the conical deficit angle of the extra dimensions. Solutions of this form provide a new arena in which to explore brane-world phenomenology and the effects of extra dimensions on the cosmological constant problem.
Confined Dirac Particles in Constant and Tilted Magnetic Field
Abdulaziz D. Alhaidari; Hocine Bahlouli; Ahmed Jellal
2012-02-23T23:59:59.000Z
We study the confinement of charged Dirac particles in 3+1 space-time due to the presence of a constant and tilted magnetic field. We focus on the nature of the solutions of the Dirac equation and on how they depend on the choice of vector potential that gives rise to the magnetic field. In particular, we select a "Landau gauge" such that the momentum is conserved along the direction of the vector potential yielding spinor wavefunctions, which are localized in the plane containing the magnetic field and normal to the vector potential. These wave functions are expressed in terms of the Hermite polynomials. We point out the relevance of these findings to the relativistic quantum Hall effect and compare with the results obtained for a constant magnetic field normal to the plane in 2+1 dimensions.
Estimation of the effective distribution coefficient from the solubility constant
Wang, Yug-Yea; Yu, C.
1994-07-01T23:59:59.000Z
An updated version of RESRAD has been developed by Argonne National Laboratory for the US Department of Energy to derive site-specific soil guidelines for residual radioactive material. In this updated version, many new features have been added to the, RESRAD code. One of the options is that a user can input a solubility constant to limit the leaching of contaminants. The leaching model used in the code requires the input of an empirical distribution coefficient, K{sub d}, which represents the ratio of the solute concentration in soil to that in solution under equilibrium conditions. This paper describes the methodology developed to estimate an effective distribution coefficient, Kd, from the user-input solubility constant and the use of the effective K{sub d} for predicting the leaching of contaminants.
Mega-masers, Dark Energy and the Hubble Constant
Lo, Fred K. Y.
2007-10-15T23:59:59.000Z
Powerful water maser emission (water mega-masers) can be found in accretion disks in the nuclei of some galaxies. Besides providing a measure of the mass at the nucleus, such mega-masers can be used to determine the distance to the host galaxy, based on a kinematic model. We will explain the importance of determining the Hubble Constant to high accuracy for constraining the equation of state of Dark Energy and describe the Mega-maser Cosmology Project that has the goal of determining the Hubble Constant to better than 3%. Time permitting, we will also present the scientific capabilities of the current and future NRAO facilities: ALMA, EVLA, VLBA and GBT, for addressing key astrophysical problems
Asymptotically Flat Wormhole Solutions in a Generic Cosmological Constant Background
Y. Heydarzade; N. Riazi; H. Moradpour
2015-01-09T23:59:59.000Z
There are a number of reasons to study wormholes with generic cosmological constant $\\Lambda$. Recent observations indicate that present accelerating expansion of the universe demands $\\Lambda>0$. On the other hand, some extended theories of gravitation such as supergravity and superstring theories posses vacuum states with $\\Lambdaenergy density and pressure profiles which support such a geometry are obtained. It is shown that for having such a geometry, the wormhole throat $r_0$, the cosmological constant $\\Lambda$ and the equation of state parameter $\\omega$ should satisfy two specific conditions. The possibility of setting different values for the parameters of the model helps us to find exact solutions for the metric functions, mass functions and energy-momentum profiles. At last, the volume integral quantifier, which provides useful information about the total amount of energy condition violating matter is discussed briefly.
$\\hbar$ as a Physical Constant of Classical Optics and Electrodynamics
Tremblay, Real; Allen, Claudine Ni
2015-01-01T23:59:59.000Z
The Planck constant ($\\hbar$) plays a pivotal role in quantum physics. Historically, it has been proposed as postulate, part of a genius empirical relationship $E=\\hbar \\omega$ in order to explain the intensity spectrum of the blackbody radiation for which classical electrodynamic theory led to an unacceptable prediction: The ultraviolet catastrophe. While the usefulness of the Planck constant in various fields of physics is undisputed, its derivation (or lack of) remains unsatisfactory from a fundamental point of view. In this paper, the analysis of the blackbody problem is performed with a series expansion of the electromagnetic field in terms of TE, TM modes in a metallic cavity with small losses, that leads to developing the electromagnetic fields in a \\textit{complete set of orthonormal functions}. This expansion, based on coupled power theory, maintains both space and time together enabling modeling of the blackbody's evolution toward equilibrium. Reaching equilibrium with a multimodal waveguide analysi...
Photon-Axion-Like Particle Coupling Constant and Cosmological Observations
M. Yu. Piotrovich; Yu. N. Gnedin; T. M. Natsvlishvili
2008-05-23T23:59:59.000Z
We estimated the photon-pseudoscalar particle mixing constant from the effect of cosmological alignment and cosmological rotation of polarization plane of distant QSOs. This effect is explained in terms of birefringent phenomenon due to photon-pseudoscalar (axion-like) particle mixing in a cosmic magnetic field. On the contrary, one can estimate the strength of the cosmic magnetic field using the constraints on the photon-axion-like particle coupling constant from the CAST experiment and from SNe Ia dimming effect. In a result, the lower limit on the intergalactic ($z\\approx 1\\div 2$) magnetic field appears at the level of about $4\\times 10^{-10}\\div 10^{-11}$ G.
Thermodynamics of de Sitter Black Holes: Thermal Cosmological Constant
Yuichi Sekiwa
2006-04-10T23:59:59.000Z
We study the thermodynamic properties associated with the black hole event horizon and the cosmological horizon for black hole solutions in asymptotically de Sitter spacetimes. We examine thermodynamics of these horizons on the basis of the conserved charges according to Teitelboim's method. In particular, we have succeeded in deriving the generalized Smarr formula among thermodynamical quantities in a simple and natural way. We then show that cosmological constant must decrease when one takes into account the quantum effect. These observations have been obtained if and only if cosmological constant plays the role of a thermodynamical state variable. We also touch upon the relation between inflation of our universe and a phase transition of black holes.
New process to avoid emissions: Constant pressure in coke ovens
Giertz, J.; Huhn, F. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). Inst. for Cokemaking and Fuel Technology; Hofherr, K. [Thyssen Stahl AG, Duisburg (Germany)
1995-12-01T23:59:59.000Z
A chamber pressure regulation (PROven), especially effective in regard to emission control problems of coke ovens is introduced for the first time. Because of the partial vacuum in the collecting main system, it is possible to keep the oven`s raw gas pressure constant on a low level over the full coking time. The individual pressure control for each chamber is assured directly as a function of the oven pressure by an immersion system controlling the flow resistance of the collecting main valve. The latter is a fixed-position design (system name ``FixCup``). By doing away with the interdependence of collecting main pressure and chamber pressure, a parameter seen as a coking constant could not be made variable. This opens a new way to reduce coke oven emissions and simultaneously to prevent the ovens from damage caused by air ingress into the oven.
The Stückelberg Holographic Superconductors in Constant External Magnetic Field
Jian-Pin Wu
2010-07-08T23:59:59.000Z
We investigate the St\\"{u}ckelberg holographic superconductor in present of the constant external magnetic field. We observe that a critical value of magnetic field exists as the cases in usual holographic superconductor. Furthermore, we find that the applied magnetic field strongly influence the phase transition of this model and have a jump in the condensate at the critical temperature even for $c_{4}=1$.
The strong coupling constant at low Q^2
Alexandre Deur
2005-06-06T23:59:59.000Z
We extract an effective strong coupling constant using low-Q{sup 2} data and sum rules. Its behavior is established over the full Q{sup 2}-range and is compared to calculations based on lattice QCD, Schwinger-Dyson equations and a quark model. Although the connection between all these quantities is not known yet, the results are surprisingly alike. Such a similitude may be related to quark-hadron duality.
Scaling behavior of discretization errors in renormalization and improvement constants
Bhattacharya, T; Lee, W; Sharpe, S R; Bhattacharya, Tanmoy; Gupta, Rajan; Lee, Weonjong; Sharpe, Stephen R.
2006-01-01T23:59:59.000Z
Non-perturbative results for improvement and renormalization constants needed for on-shell and off-shell O(a) improvement of bilinear operators composed of Wilson fermions are presented. The calculations have been done in the quenched approximation at beta=6.0, 6.2 and 6.4. To quantify residual discretization errors we compare our data with results from other non-perturbative calculations and with one-loop perturbation theory.
Turbine blade having a constant thickness airfoil skin
Marra, John J
2012-10-23T23:59:59.000Z
A turbine blade is provided for a gas turbine comprising: a support structure comprising a base defining a root of the blade and a framework extending radially outwardly from the base, and an outer skin coupled to the support structure framework. The skin has a generally constant thickness along substantially the entire radial extent thereof. The framework and the skin define an airfoil of the blade.
Noncommutative field with constant background fields and neutral fermion
Cui-bai Luo; Feng-yao Hou; Zhu-fang Cui; Xiao-jun Liu; Hong-shi Zong
2015-03-02T23:59:59.000Z
Introducing constant background fields into the noncommutative gauge theory, we first obtain a Hermitian fermion Lagrangian which involves a Lorentz violation term, then we generalize it to a new deformed canonical noncommutation relations for fermion field. Massless neutrino oscillation in the deformed canonical noncommutation relations is analyzed. The restriction of the noncommutative coefficients is also discussed. By comparing with the existing experimental data of conventional neutrino oscillations, the order of noncommutative deformed coefficients is given from different ways.
Numerical computation of constant mean curvature surfaces using finite elements
Jan Metzger
2004-08-18T23:59:59.000Z
This paper presents a method for computing two-dimensional constant mean curvature surfaces. The method in question uses the variational aspect of the problem to implement an efficient algorithm. In principle it is a flow like method in that it is linked to the gradient flow for the area functional, which gives reliable convergence properties. In the background a preconditioned conjugate gradient method works, that gives the speed of a direct elliptic multigrid method.
Apparatus producing constant cable tension for intermittent demand
Lauritzen, T.
1984-05-23T23:59:59.000Z
This invention relates to apparatus for producing constant tension in cable or the like when it is unreeled and reeled from a drum or spool under conditions of intermittent demand. The invention is particularly applicable to the handling of superconductive cable, but the invention is also applicable to the unreeling and reeling of other strands, such as electrical cable, wire, cord, other cables, fish line, wrapping paper and numerous other materials.
Adams, Amy Lynn
2011-01-01T23:59:59.000Z
This thesis evaluates the constant rate of strain and constant head techniques for measurement of the hydraulic conductivity of fine grained soils. A laboratory program compares hydraulic conductivity measurements made ...
Hydrogen Atom and Time Variation of Fine-Structure Constant
Mu-Lin Yan
2009-11-21T23:59:59.000Z
In this paper, we have solved the de Sitter special relativistic ($\\mathcal{SR}_{cR}$-) Dirac equation of hydrogen in the earth-QSO(quasar) framework reference by means of the adiabatic approach. The aspects of geometry effects of de Sitter space-time described by Beltrami metric are explored and taken into account. It is found that the $\\mathcal{SR}_{cR}$-Dirac equation of hydrogen is a time dependent quantum Hamiltonian system. We provide an explicit calculation to justify the adiabatic approach in dealing with this time-dependent system. Since the radius of de Sitter sphere $R$ is cosmologically large, the evolution of the system is very slow so that the adiabatic approximation legitimately works with high accuracy. We conclude that the electromagnetic fine-structure constant, the electron mass and the Planck constant are time variations. This prediction of fine-structure constant is consistent with the presently available observation data. For confirming it further, experiments/observations are required.
The Effective Fine Structure Constant at TESLA Energies
F. Jegerlehner
2001-05-27T23:59:59.000Z
We present a new estimate of the hadronic contribution to the shift in the fine structure constant at LEP and TESLA energies and calculate the effective fine structure constant. Substantial progress in a precise determination of this important parameter is a consequence of substantially improved total cross section measurements by the BES II collaboration and an improved theoretical understanding. In the standard approach which relies to a large extend on experimental data we find $\\Delta \\al_{\\rm hadrons}^{(5)}(\\mz) = 0.027896 \\pm 0.000395$ which yields $\\alpha^{-1}(\\mz) = 128.907 \\pm 0.054$. Another approach, using the Adler function as a tool to compare theory and experiment, allows us to to extend the applicability of perturbative QCD in a controlled manner. The result in this case reads $\\Delta\\alpha^{(5)}_{\\rm had}(M_Z^2) = 0.027730 \\pm 0.000209$ and hence $\\alpha^{-1}(\\mz) = 128.930 \\pm 0.029$. At TESLA energies a new problem shows up with the definition of an effective charge. A possible solution of the problem is presented. Prospects for further progress in a precise determination of the effective fine structure constant are discussed.
Stars In Other Universes: Stellar structure with different fundamental constants
Fred C. Adams
2008-07-23T23:59:59.000Z
Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem tractable, we develop a semi-analytical stellar structure model that allows for physical understanding of these stars with unconventional parameters, as well as a means to survey the relevant parameter space. In this work, the most important quantities that determine stellar properties -- and are allowed to vary -- are the gravitational constant $G$, the fine structure constant $\\alpha$, and a composite parameter $C$ that determines nuclear reaction rates. Working within this model, we delineate the portion of parameter space that allows for the existence of stars. Our main finding is that a sizable fraction of the parameter space (roughly one fourth) provides the values necessary for stellar objects to operate through sustained nuclear fusion. As a result, the set of parameters necessary to support stars are not particularly rare. In addition, we briefly consider the possibility that unconventional stars (e.g., black holes, dark matter stars) play the role filled by stars in our universe and constrain the allowed parameter space.
Electronic transport in two-dimensional high dielectric constant nanosystems
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ortuño, M.; Somoza, A. M.; Vinokur, V. M.; Baturina, T. I.
2015-04-10T23:59:59.000Z
There has been remarkable recent progress in engineering high-dielectric constant two dimensional (2D) materials, which are being actively pursued for applications in nanoelectronics in capacitor and memory devices, energy storage, and high-frequency modulation in communication devices. Yet many of the unique properties of these systems are poorly understood and remain unexplored. Here we report a numerical study of hopping conductivity of the lateral network of capacitors, which models two-dimensional insulators, and demonstrate that 2D long-range Coulomb interactions lead to peculiar size effects. We find that the characteristic energy governing electronic transport scales logarithmically with either system size or electrostatic screeningmore »length depending on which one is shorter. Our results are relevant well beyond their immediate context, explaining, for example, recent experimental observations of logarithmic size dependence of electric conductivity of thin superconducting films in the critical vicinity of superconductor-insulator transition where a giant dielectric constant develops. Our findings mark a radical departure from the orthodox view of conductivity in 2D systems as a local characteristic of materials and establish its macroscopic global character as a generic property of high-dielectric constant 2D nanomaterials.« less
On the Definitions of Entanglement Spacing and Time Constants in the Tube R.G. Larson*
quantities, including the temperature T, Boltzmann's constant kB, and Avogadro's number NA, from which
Paris-Sud XI, Université de
'application est faite aux molécules SF6 et UF6. 4 constantes cubiques de SF6 ont été déterminées à partir des for the centrifugal distortion constants as a function of harmonic frequencies ; application is made to SF6 and UF6. 4 cubic constants of SF6 have been calculated from the rotational constants. Tome 42 N" 3 1«· FEVRIER 1981
On the possibility of variation of the fundamental constants of physics in the static universe
V. Jonauskas
1999-08-09T23:59:59.000Z
A variation of fundamental constants of physics is proposed in a frame of static universe. It is shown when the velocity of light increases (decreases) the Planck's constant increases (decreases) and mass of bodies decreases (increases). This variation of constants leads to the variation of dimensions of bodies and the energy levels of atoms, but a fine structure constant remains unaltered.
The variation of the fine-structure constant from disformal couplings
van de Bruck, Carsten; Nunes, Nelson J
2015-01-01T23:59:59.000Z
We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, alpha. As a result, the theory we consider can explain the non-zero reported variation in the evolution of alpha by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of alpha. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical r...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Appointment Types Postdoc Appointment Types Most postdocs will be offered a postdoctoral research associate appointment. Each year, approximately 30 Postdoctoral Fellow...
Broader source: Energy.gov [DOE]
Several commissioning types exist to address the specific needs of equipment and systems across both new and existing buildings. The following commissioning types provide a good overview.
Evaluation of the cosmological constant in inflation with a massive non-minimal scalar field
Huang, Jung-Jeng
2015-01-01T23:59:59.000Z
In Schroedinger picture we study the possible effects of trans-Planckian physics on the quantum evolution of massive non-minimally coupled scalar field in de Sitter space. For the nonlinear Corley-Jacobson type dispersion relations with quartic or sextic correction, we obtain the time evolution of the vacuum state wave functional during slow-roll inflation, and calculate explicitly the corresponding expectation value of vacuum energy density. We find that the vacuum energy density is finite. For the usual dispersion parameter choice, the vacuum energy density for quartic correction to the dispersion relation is larger than for sextic correction, while for some other parameter choices, the vacuum energy density for quartic correction is smaller than for sextic correction. We also use the backreaction to constrain the magnitude of parameters in nonlinear dispersion relation, and show how the cosmological constant depends on the parameters and the energy scale during the inflation at the grand unification phase ...
Degravitation, inflation and the cosmological constant as an afterglow
Patil, Subodh P., E-mail: subodh@physik.hu-berlin.de [Humboldt Universitaet zu Berlin, Institut fuer Physik, Newtonstrasse 15, D-12489 Berlin (Germany)
2009-01-15T23:59:59.000Z
In this report, we adopt the phenomenological approach of taking the degravitation paradigm seriously as a consistent modification of gravity in the IR, and investigate its consequences for various cosmological situations. We motivate degravitation - where Netwon's constant is promoted to a scale dependent filter function - as arising from either a small (resonant) mass for the graviton, or as an effect in semi-classical gravity. After addressing how the Bianchi identities are to be satisfied in such a set up, we turn our attention towards the cosmological consequences of degravitation. By considering the example filter function corresponding to a resonantly massive graviton (with a filter scale larger than the present horizon scale), we show that slow roll inflation, hybrid inflation and old inflation remain quantitatively unchanged. We also find that the degravitation mechanism inherits a memory of past energy densities in the present epoch in such a way that is likely significant for present cosmological evolution. For example, if the universe underwent inflation in the past due to it having tunneled out of some false vacuum, we find that degravitation implies a remnant 'afterglow' cosmological constant, whose scale immediately afterwards is parametrically suppressed by the filter scale (L) in Planck units {Lambda} {approx} l{sup 2}{sub pl}/L{sup 2}. We discuss circumstances through which this scenario reasonably yields the presently observed value for {Lambda} {approx} O(10{sup -120}). We also find that in a universe still currently trapped in some false vacuum state, resonance graviton models of degravitation only degravitate initially Planck or GUT scale energy densities down to the presently observed value over timescales comparable to the filter scale. We argue that different functional forms for the filter function will yield similar conclusions. In this way, we argue that although the degravitation models we study have the potential to explain why the cosmological constant is not large in addition to why it is not zero, it does not satisfactorily address the co-incidence problem without additional tuning.
Maximum Tension: with and without a cosmological constant
Barrow, John D.; Gibbons, G. W.
2014-12-04T23:59:59.000Z
(and the ?uid pressure, p) diverges even though a; _a and the ?uid density ? remain ?nite, even though ? + 3p > 0 always. 2 The e¤ect of the cosmological constant Recently, David Thornton (private communication) has raised the question of how... of a mass-radius diagram (Carr and Rees, 1979, Barrow and Tipler, 1986). All bodies, at rest, may be assigned a mass M and a radius or size R. Since inertial mass, passive gravitational mass, and active gravitational mass 7 are equal to a high degree...
Determining coal permeabilities through constant pressure production interference testing
Schubarth, Stephen Kurt
1983-01-01T23:59:59.000Z
Kurt Schubarth, B. S. , Texas A&M Un1versity Chairman of Advisory Committee: Dr. Stephen A. Holditch The determination of format1on propert1es 1s important to the success of any underground coal gasification (UCG) project. There are many ways... method of analysis for a mult1ple well test w1th a constant pressure source. The method is then verified by analyzing data generated from a numer1cal reservoir simulator. An analys1s of a hydrology test performed during the 1980 Texas ASM UCG project...
Photon propagation in noncommutative QED with constant external field
R. Fresneda; D. M. Gitman; A. E. Shabad
2015-01-20T23:59:59.000Z
We find dispersion laws for the photon propagating in the presence of mutually orthogonal constant external electric and magnetic fields in the context of the $\\theta $-expanded noncommutative QED. We show that there is no birefringence to the first order in the noncommutativity parameter $% \\theta .$ By analyzing the group velocities of the photon eigenmodes we show that there occurs superluminal propagation for any direction. This phenomenon depends on the mutual orientation of the external electromagnetic fields and the noncommutativity vector. We argue that the propagation of signals with superluminal group velocity violates causality in spite of the fact that the noncommutative theory is not Lorentz-invariant and speculate about possible workarounds.
Photon propagation in noncommutative QED with constant external field
Fresneda, R; Shabad, A E
2015-01-01T23:59:59.000Z
We find dispersion laws for the photon propagating in the presence of mutually orthogonal constant external electric and magnetic fields in the context of the $\\theta $-expanded noncommutative QED. We show that there is no birefringence to the first order in the noncommutativity parameter $% \\theta .$ By analyzing the group velocities of the photon eigenmodes we show that there occurs superluminal propagation for any direction. This phenomenon depends on the mutual orientation of the external electromagnetic fields and the noncommutativity vector. We argue that the propagation of signals with superluminal group velocity violates causality in spite of the fact that the noncommutative theory is not Lorentz-invariant and speculate about possible workarounds.
Big bang nucleosynthesis as a probe of fundamental "constants"
Thomas Dent; Steffen Stern
2007-10-25T23:59:59.000Z
Big Bang nucleosynthesis (BBN) is the earliest sensitive probe of the values of many fundamental particle physics parameters. We have found the leading linear dependences of primordial abundances on all relevant parameters of the standard BBN code, including binding energies and nuclear reaction rates. This enables us to set limits on possible variations of fundamental parameters. We find that 7Li is expected to be significantly more sensitive than other species to many fundamental parameters, a result which also holds for variations of coupling strengths in grand unified (GUT) models. Our work also indicates which areas of nuclear theory need further development if the values of ``constants'' are to be more accurately probed.
Confined System with Rashba Coupling in Constant Magnetic Field
Mohammed El Bouziani; Rachid Houca; Ahmed Jellal
2012-04-30T23:59:59.000Z
We study a two dimensional system of electrons with Rashba coupling in the constant magnetic field $B$ and confining potential. We algebraically diagonalize the corresponding Hamiltonian to end up with the solutions of the energy spectrum. In terms of two kinds of operator we construct two symmetries and discuss the filling of the shells with electrons for strong and weak $B$. Subsequently, we show that our system is sharing some common features with quantum optics where the exact operator solutions for the basics Jaynes-Cummings variables are derived from our results. An interesting limit is studied and the corresponding quantum dynamics is recovered.
Types of Lights Types of Lights
1 Types of Lights Types of Lights q So far we have studied point lights Radiate in all direc7ons q Other lights Direc7onal lights (posi7on-independent) Spotlights #12;2 Direc1onal Lights q Shine in a single, uniform direc7on q All rays
Fluctuation of an ion beam extracted from an AC filament driven Bernas-type ion source
Miyamoto, N., E-mail: nmiyamot@mail.doshisha.ac.jp; Okajima, Y.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)] [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)
2014-02-15T23:59:59.000Z
Argon ion beam fluctuation from an AC filament driven Bernas-type ion source is observed. The ion beam was measured by an 8 measurement elements beam profile monitor. The amplitude of the beam current fluctuation stayed in the same level from 100 Hz to 1 kHz of the filament heating frequency. The beam current fluctuation frequency measured by the beam profile monitor was equal to the frequency of the AC filament operation. The fluctuation amplitudes of the beam current by AC operation were less than 7% and were in the same level of the DC operation.
Charmed and light pseudoscalar meson decay constants from HISQ simulations
A. Bazavov; C. Bernard; C. Bouchard; C. DeTar; D. Du; A. X. El-Khadra; J. Foley; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. Kim; J. Komijani; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; J. N. Simone; R. L. Sugar; D. Toussaint; R. S. Van de Water; R. Zhou
2014-11-10T23:59:59.000Z
We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$, and the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD. We use the MILC highly improved staggered quark (HISQ) ensembles with four dynamical quark flavors. Our primary results are $f_{D^+} = 212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} = 249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} = 1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total systematic, respectively. We also obtain $f_{K^+}/f_{\\pi^+} = 1.1956(10)({}^{+26}_{-18})$, updating our previous result, and determine the quark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and $m_c/m_s = 11.747(19)({}^{+59}_{-43})$. When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements $|V_{us}| = 0.22487(51) (29)(20)(5)$, $|V_{cd}|=0.217(1) (5)(1)$ and $|V_{cs}|= 1.010(5)(18)(6)$, where the errors are from this calculation of the decay constants, the uncertainty in the experimental decay rates, structure-dependent electromagnetic corrections, and, in the case of $|V_{us}|$, the uncertainty in $|V_{ud}|$, respectively.
Determining the Hubble constant using HII regions and HII galaxies
Chavez, Ricardo; Terlevich, Roberto; Plionis, Manolis; Bresolin, Fabio; Basilakos, Spyros; Melnick, Jorge
2012-01-01T23:59:59.000Z
We report the first results of a long term program aiming to provide accurate independent estimates of the Hubble constant (H0) and the Dark Energy equation of state parameter (w) using the L(Hbeta)-velocity dispersion (sigma) distance estimator for Giant HII regions and HII galaxies. We have used VLT and Subaru high dispersion spectroscopic observations of a local sample of HII galaxies, identified in the SDSS DR7 catalogue in order to re-define and improve the L(Hbeta) - sigma distance indicator and to determine the Hubble constant. To this end we used as local calibration or 'anchor' of this correlation, giant HII regions in nearby galaxies which have accurate distance measurements determined via primary indicators. Using our best sample of 89 nearby HII galaxies and 23 Giant HII regions in 9 galaxies we obtain H0 = 73.9+- 2.7 (statistical)+- 2.9 (systematic) km s-1 Mpc-1, in excellent agreement with, and independently confirming, the most recent SNe Ia based results.
Axial-vector coupling constants and chiral-symmetry restoration
Henley, E.M. (Department of Physics FM-15 and Institute for Nuclear Theory HN-12, University of Washington, Seattle, Washington 98195 (United States)); Hwang, W.P. (Department of Physics, National Taiwan University, Taipei, Taiwan 10764 (Taiwan, Province of China)); Kisslinger, L.S. (Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213 (United States))
1992-07-01T23:59:59.000Z
The isovector axial-vector coupling constant {ital g}{sub {ital A}} is determined by using the method of QCD sum rules. A sum rule for ({ital g}{sub {ital A}}{minus}1) is obtained, and it is shown that, with standard values of the quark condensates, {ital g}{sub {ital A}}=1.26{plus minus}0.08. It is also shown that the isovector axial-vector coupling ({ital g}{sub {ital A}}{minus}1)=0 in the limit in which chiral symmetry is restored, and the quark condensate vanishes. A sum rule is also obtained for the isoscalar'' axial-vector coupling constant {ital g}{sub {ital A}}{sup {ital S}}, which is found to be 0.13 if the isovector values of susceptibilities are used. On the other hand, {ital g}{sub {ital A}}{sup {ital S}}={minus}0.68 if the quark condensate is set to zero while {ital g}{sub {ital A}}{sup {ital S}}={minus}1.00 if both the quark and gluon condensates vanish in the event of chiral-symmetry restoration. The values of {ital g}{sub {ital A}} and {ital g}{sub {ital A}}{sup {ital S}} allow us to deduce {Delta}{ital u} and {Delta}{ital d} in the proton.
Silica aerogel: An intrinsically low dielectric constant material
Hrubesh, L.W.
1995-04-01T23:59:59.000Z
Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.
Zero-Branes, Quantum Mechanics and the Cosmological Constant
Andrew Chamblin; Neil D. Lambert
2001-07-25T23:59:59.000Z
We analyse some dynamical issues in a modified type IIA supergravity, recently proposed as an extension of M-theory that admits de Sitter space. In particular we find that this theory has multiple zero-brane solutions. This suggests a microscopic quantum mechanical matrix description which yields a massive deformation of the usual M(atrix) formulation of M-theory and type IIA string theory.
Zhang, WJ "Chris"
) motor and servo-motor. If a system contains two drivers or more, among which some are of the CV motor while the other are the servo-motor, the system has the so-called hybrid driver architecture is stable. A simulation is performed to show verify the proposed controller. The CV motor has the velocity
When did vacuum energy of the Universe become cosmological constant?
V. Burdyuzha
2007-12-29T23:59:59.000Z
A quark-gluon phase transition in the Universe is researched after which vacuum (dark) energy has hardened and become cosmological constant. Before this a vacuum component of the Universe was changing by jumps during phase transitions since vacuum condensates of quantum fields carried a negative contribution in its positive density energy. This quintessence period of the Universe life took place during the first parts of a second when our Universe was losing high symmetry. Using Zel'dovich's formula the modern value of vacuum energy is also calculated. It is shown that a quantum chromodynamical vacuum which is characterized by pseudogoldstone bosons existed definitely when temperature of the Universe was T~150 MeV. Therefore there is a large probability that dark energy is vacuum energy.
Testing the cosmological constant as a candidate for dark energy
Kratochvil, Jan; Linde, Andrei; Linder, Eric V.; Shmakova, Marina
2003-12-03T23:59:59.000Z
It may be difficult to single out the best model of dark energy on the basis of the existing and planned cosmological observations, because many different models can lead to similar observational consequences. However, each particular model can be studied and either found consistent with observations or ruled out. In this paper, we concentrate on the possibility to test and rule out the simplest and by far the most popular of the models of dark energy, the theory described by general relativity with positive vacuum energy (the cosmological constant). We evaluate the conditions under which this model could be ruled out by the future observations made by the Supernova/Acceleration Probe SNAP (both for supernovae and weak lensing) and by the Planck Surveyor cosmic microwave background satellite.
Second Law Analysis of Constant Temperature Diesel Combustion
Druecke, Dr. Ben [University of Wisconsin; Foster, Prof. Dave [University of Wisconsin; Klein, Prof. Sandy [University of Wisconsin; Daw, C Stuart [ORNL; Chakravarthy, Veerathu K [ORNL; Graves, Ronald L [ORNL
2006-01-01T23:59:59.000Z
The results from a second law analysis of a constant temperature diesel combustion process are presented and show that this process is not significantly more reversible than conventional combustion. In addition to quantifying the total availability destruction in combustion, the magnitudes of the combustion irreversibilities attributable to each irreversible subprocess (mixing, oxidation and internal heat transfer) were determined. The primary contributor to combustion irreversibilities is the thermal interaction of reacting and non-reacting species during the oxidation and internal thermal energy transfer subprocesses. Increasing combustion temperature significantly decreases availability destruction by making the oxidation and internal thermal energy transfer processes more reversible. While increasing combustion temperature decreases combustion irreversibility, it also results in an increase in exhaust temperature. A tradeoff exists between large availability destruction at low combustion temperatures and large amounts of availability discarded in the exhaust at high combustion temperatures. The optimum amount of work was found to occur for a combustion temperature of approximately 1600 K.
Does Quantum Cosmology Predict a Constant Dilatonic Field?
F. G. Alvarenga; A. B. Batista; J. C. Fabris
2004-04-07T23:59:59.000Z
Quantum cosmology may permit to determine the initial conditions of the Universe. In particular, it may select a specific model between many possible classical models. In this work, we study a quantum cosmological model based on the string effective action coupled to matter. The Schutz's formalism is employed in the description of the fluid. A radiation fluid is considered. In this way, a time coordinate may be identified and the Wheeler-DeWitt equation reduces in the minisuperspace to a Schr\\"odinger-like equation. It is shown that, under some quite natural assumptions, the expectation values indicate a null axionic field and a constant dilatonic field. At the same time the scale factor exhibits a bounce revealing a singularity-free cosmological model. In some cases, the mininum value of the scale factor can be related to the value of gravitational coupling.
Statistical Inference for Models with Intractable Normalizing Constants
Jin, Ick Hoon
2011-06-27T23:59:59.000Z
be calculated by S1(y) = X 1?i
Path Integral Confined Dirac Fermions in a Constant Magnetic Field
Abdeldjalil Merdaci; Ahmed Jellal; Lyazid Chetouani
2014-04-17T23:59:59.000Z
We consider Dirac fermion confined in harmonic potential and submitted to a constant magnetic field. The corresponding solutions of the energy spectrum are obtained by using the path integral techniques. For this, we begin by establishing a symmetric global projection, which provides a symmetric form for the Green function. Based on this, we show that it is possible to end up with the propagator of the harmonic oscillator for one charged particle. After some transformations, we derive the normalized wave functions and the eigenvalues in terms of different physical parameters and quantum numbers. By interchanging quantum numbers, we show that our solutions possed interesting properties. The density of current and the non-relativistic limit are analyzed where different conclusions are obtained.
Confined Dirac Fermions in a Constant Magnetic Field
Ahmed Jellal; Abdulaziz D. Alhaidari; Hocine Bahlouli
2009-04-03T23:59:59.000Z
We obtain an exact solution of the Dirac equation in (2+1)-dimensions in the presence of a constant magnetic field normal to the plane together with a two-dimensional Dirac-oscillator potential coupling. The solution space consists of a positive and negative energy solution, each of which splits into two disconnected subspaces depending on the sign of an azimuthal quantum number, k = 0, \\pm 1, \\pm 2,... and whether the cyclotron frequency is larger or smaller than the oscillator frequency. The spinor wavefunction is written in terms of the associated Laguerre polynomials. For negative k, the relativistic energy spectrum is infinitely degenerate due to the fact that it is independent of k. We compare our results with already published work and point out the relevance of these findings to a systematic formulation of the relativistic quantum Hall effect in a confining potential.
The Arrow of Time Forbids a Positive Cosmological Constant $?$
Laura Mersini-Houghton
2007-04-20T23:59:59.000Z
Motivated by the mounting evidence for dark energy, here we explore the consequences of a fundamental cosmological constant $\\Lambda$ for our universe. We show that when the gravitational entropy of a pure DeSitter state ultimately wins over matter, then the thermodynamic arrow of time in our universe must reverse in scales of order a Hubble time. We find that due to the dynamics of gravity and nonlocal entanglement, a finite size system such as a DeSitter patch with horizon size $H_0^{-1}$ has a finite lifetime $\\Delta t$. This phenomenon arises from the dynamic gravitational instabilities that develop during a DeSitter epoch and turn catastrophic. A reversed arrow of time is clearly in disagreement with observations. Thus we are led to conclude: Nature forbids a fundamental $\\Lambda$. Or else general relativity must be modified in the IR regime when $\\Lambda$ dominates the expansion of the Universe.
Vacuum Energy and Cosmological Constant Problem in Krein Quantization Approach
Pejhan, H
2014-01-01T23:59:59.000Z
In this paper, we consider a new version of indefinite metric field quantization called "Krein" quantization approach, where the field operators are constructed by both positive and negative energy/frequency modes, or simply physical and un-physical states. Centering on the zero-point energy, fundamental subjects revolve around this concept will be discussed. In fact the presence of un-physical states in the theory performing as natural renormalizing tools, automatically removes the infinite terms in zero-point energy and expectation value of the energy-momentum tensor, so we are capable of defining absolute meaning for energy. Thus, the method presents an interesting property linked to the cosmological constant problem. Meanwhile, in order to ensure consistency of the theory, we have studied and made comparison essential issues such as unitarity of the theory, physical achievements of renormalizing process and the trace anomaly subject.
Molecular Dynamics Simulations of Solutions at Constant Chemical Potential
Perego, Claudio; Parrinello, Michele
2015-01-01T23:59:59.000Z
Molecular Dynamics studies of chemical processes in solution are of great value in a wide spectrum of applications, that range from nano-technology to pharmaceutical chemistry. However, these calculations are affected by severe finite-size effects, such as the solution being depleted as the chemical process proceeds, that influence the outcome of the simulations. To overcome these limitations, one must allow the system to exchange molecules with a macroscopic reservoir, thus sampling a Grand-Canonical ensemble. Despite the fact that different remedies have been proposed, this still represents a key challenge in molecular simulations. In the present work we propose the C$\\mu$MD method, which introduces an external force that controls the environment of the chemical process of interest. This external force, drawing molecules from a finite reservoir, maintains the chemical potential constant in the region where the process takes place. We have applied the C$\\mu$MD method to the paradigmatic case of urea crystall...
Constant power speed range extension of surface mounted PM motors
Lawler, Jack Steward (Knoxville, TN); Bailey, John Milton (Knoxville, TN)
2001-01-01T23:59:59.000Z
A circuit and method for controlling a rotating machine (11) in the constant horsepower range above base speed uses an inverter (15) having SCR's (T1-T6) connected in series with the primary commutation switches (Q1-Q6) to control turn off of the primary commutation switches and to protect the primary commutation switches from faults. The primary commutation switches (Q1-Q6) are controlled by a controller (14), to fire in advance or after a time when the back emf equals the applied voltage, and then to turn off after a precise dwell time, such that suitable power is developed at speeds up to at least six times base speed.
Comment on "Mixing and Decay Constants of Pseudoscalar Mesons"
Kirchbach, M
1999-01-01T23:59:59.000Z
The key assumption used recently by Feldmann, Kroll and Stich [Phys.Rev. D58, 114006 (1998)] that the decay constants f_\\eta, and f_\\eta ' of the respective eta and eta ' mesons in the quark flavor basis follow the pattern of strange and non--strange quarkonia mixing in their wave functions, is reproduced in identifying the non-isotriplet part of the strong neutral axial current with the genuine axial hypercharge current J_{\\mu, 5}^Y =\\bar q \\gamma_\\mu\\gamma_5 Y/2 q, where Y=C+S+B is defined by the Gell-Mann-Nakano-Nishijima relation as the sum of charm (C), strangeness (S), and baryon (B) quark quantum numbers. The inequivalence between octet and hypercharge axial currents is pointed out.
Predicting the Cosmological Constant from the Causal Entropic Principle
Bousso, Raphael; Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2007-05-01T23:59:59.000Z
We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach-weighting by the number of"observers per baryon" -- is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.
Predicting the Cosmological Constant from the CausalEntropic Principle
Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2007-02-20T23:59:59.000Z
We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, it asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach--weighting by the number of ''observers per baryon''--is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.
Scale of gravity and the cosmological constant within a landscape
Graesser, Michael L. [California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, Rutgers University, Piscataway, New Jersey 08540 (United States); Salem, Michael P. [California Institute of Technology, Pasadena, California 91125 (United States)
2007-08-15T23:59:59.000Z
It is possible that the scale of gravity, parametrized by the apparent Planck mass, may obtain different values within different universes in an encompassing multiverse. We investigate the range over which the Planck mass may scan while still satisfying anthropic constraints. The window for anthropically allowed values of the Planck mass may have important consequences for landscape predictions. For example, if the likelihood to observe some value of the Planck mass is weighted by the inflationary expansion factors of the universes that contain that value, then it appears extremely unlikely to observe the value of the Planck mass that is measured within our universe. This is another example of the runaway inflation problem discussed in recent literature. We also show that the window for the Planck mass significantly weakens the anthropic constraint on the cosmological constant when both are allowed to vary over a landscape.
Precision Measurement of the Newtonian Gravitational Constant Using Cold Atoms
G. Rosi; F. Sorrentino; L. Cacciapuoti; M. Prevedelli; G. M. Tino
2014-12-26T23:59:59.000Z
About 300 experiments have tried to determine the value of the Newtonian gravitational constant, G, so far, but large discrepancies in the results have made it impossible to know its value precisely. The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G while keeping systematic effects under control. Most previous experiments performed were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish in 1798, and in all cases macroscopic masses were used. Here we report the precise determination of G using laser-cooled atoms and quantum interferometry. We obtain the value G=6.67191(99) x 10^(-11) m^3 kg^(-1) s^(-2) with a relative uncertainty of 150 parts per million (the combined standard uncertainty is given in parentheses). Our value differs by 1.5 combined standard deviations from the current recommended value of the Committee on Data for Science and Technology. A conceptually different experiment such as ours helps to identify the systematic errors that have proved elusive in previous experiments, thus improving the confidence in the value of G. There is no definitive relationship between G and the other fundamental constants, and there is no theoretical prediction for its value, against which to test experimental results. Improving the precision with which we know G has not only a pure metrological interest, but is also important because of the key role that G has in theories of gravitation, cosmology, particle physics and astrophysics and in geophysical models.
Simulations Data Simulation Type
Wang, Xiaorui "Ray"
to request different simulations data. The flow chart above demonstrates the different steps and options@ornl.gov) Autotune Drupal 7 CMS Current building energy models (BEMs), using EnergyPlus or other simulations, are unreliable because they have to constantly be calibrated to match actual energy usage data. Currently
Broader source: Energy.gov [DOE]
The following provides greater detail regarding the types of reuse pursued for LM sites. It should be noted that many actual reuses combine several types of the uses listed below.
Marcus Hutter -1 -Bayesian Regression of Piecewise Constant Functions Bayesian Regression of
Hutter, Marcus
Marcus Hutter - 1 - Bayesian Regression of Piecewise Constant Functions Bayesian Regression6 June 2006 #12;Marcus Hutter - 2 - Bayesian Regression of Piecewise Constant Functions Table of Contents · Bayesian Regression · Quantities of Interest · Efficient Solutions by Dynamic Programming · Determination
G. L. Klimchitskaya; V. M. Mostepanenko
2015-04-09T23:59:59.000Z
We obtain improved constraints on the coupling constants of axion-like particles to nucleons from a recently performed Casimir-less experiment. For this purpose, the differential force between a Au-coated sphere and either Au or Si sectors of a rotating disc, arising due to two-axion exchange, is calculated. Over a wide region of axion masses from 1.7 meV to 0.9 eV the obtained constraints are stronger up to a factor of 60 than the previously known ones following from the Cavendish-type experiment and measurements of the effective Casimir pressure.
Klimchitskaya, G L
2015-01-01T23:59:59.000Z
We obtain stronger constraints on the coupling constants of axion-like particles to nucleons from a recently performed Casimir-less experiment. For this purpose, the differential force between a Au-coated sphe\\-re and either Au or Si sectors of a rotating disc, arising due to two-axion exchange, is calculated. Over a wide region of axion masses from 1.7 meV to 0.9 eV the obtained constraints are stronger up to a factor of 60 than the previously known ones following from the Cavendish-type experiment and measurements of the effective Casimir pressure.
FOURTH-ORDER ELASTIC CONSTANTS: GENERAL METHOD FOR DETERMINATION AND APPLICATIONS X. Markenscoff
Paris-Sud XI, Université de
FOURTH-ORDER ELASTIC CONSTANTS: GENERAL METHOD FOR DETERMINATION AND APPLICATIONS X. Markenscoff.- A list of the independent fourth-order elastic constants (FOEC's) and the interpenden- cies among the non. The fourth-order elastic constants are related to the second-derivatives of the wave velocity with respect
Paris-Sud XI, Université de
New Variation of Constants Formula for Some Partial Functional Differential Equations with Infinite, Morocco ezzinbi@ucam.ac.ma Abstract In this work, we give a new variation of constants formula for some words and phrases: Hille-Yosida operator, integral solutions, variation of constants formula, uniform
Estimation of the optical constants and the thickness of thin lms using unconstrained
Martínez, José Mario
Estimation of the optical constants and the thickness of thin #12;lms using unconstrained, spectral gradient method, optical constants, thin #12;lms. 1 #12; Proposed running head: Estimation of optical constants of thin #12;lms using SGM Corresponding author: Jos#19;e Mario Mart#19;#16;nez
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics
Takada, Shoji
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics Kengo,Myodaiji, Okazaki 444. Japan (Received 28 September 1993; accepted 8 December 1993) The constant centrifugal of such practically useful approxima- tions the constant centrifugal potential approximation (CCPA) (or the energy
Physics 250 -Measurements of the Fine Structure Constant Derek Kimball January 2000 1
Budker, Dmitry
Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 1 #12;Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 2 #12;Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 3 #12;Physics 250 - Measurements
On the nature of rapidly fading Type II supernovae
Moriya, Takashi J; Ergon, Mattias; Blinnikov, Sergei I
2015-01-01T23:59:59.000Z
It has been suggested that Type II supernovae with rapidly fading light curves (a.k.a. Type IIL supernovae) are explosions of progenitors with low-mass hydrogen-rich envelopes which are of the order of 1 Msun. We investigate light-curve properties of supernovae from such progenitors. We confirm that such progenitors lead to rapidly fading Type II supernovae. We find that the luminosity of supernovae from such progenitors with the canonical explosion energy of 1e51 erg and 56Ni mass of 0.05 Msun can increase temporarily shortly before all the hydrogen in the envelope recombines. As a result, a bump appears in their light curves. The bump appears because the heating from the nuclear decay of 56Ni can keep the bottom of hydrogen-rich layers in the ejecta ionized, and thus the photosphere can stay there for a while. We find that the light-curve bump becomes less significant when we make explosion energy larger (>~ 2e51 erg), 56Ni mass smaller (<~ 0.01 Msun), 56Ni mixed in the ejecta, or the progenitor radius l...
NIHAO III: The constant disc gas mass conspiracy
Stinson, G S; Wang, L; Macciò, A V; Herpich, J; Bradford, J D; Quinn, T R; Wadsley, J; Keller, B
2015-01-01T23:59:59.000Z
We show that the cool gas masses of galactic discs reach a steady state that lasts many Gyr after their last major merger in cosmological hydrodynamic simulations. The mass of disc gas, M$_{\\rm gas}$, depends upon a galaxy halo's spin and virial mass, but not upon stellar feedback. Halos with low spin have high star formation efficiency and lower disc gas mass. Similarly, lower stellar feedback leads to more star formation so the gas mass ends up nearly the same irregardless of stellar feedback strength. Even considering spin, the M$_{\\rm gas}$ relation with halo mass, M$_{200}$ only shows a factor of 3 scatter. The M$_{\\rm gas}$--M$_{200}$ relation show a break at M$_{200}$=$2\\times10^{11}$ M$_\\odot$ that corresponds to an observed break in the M$_{\\rm gas}$--M$_\\star$ relation. The constant disc mass stems from a shared halo gas density profile in all the simulated galaxies. In their outer regions, the profiles are isothermal. Where the profile rises above $n=10^{-3}$ cm$^{-3}$, the gas readily cools and th...
Distribution Function of Dark Matter with Constant Anisotropy
Ding Ma; Ping He
2008-08-01T23:59:59.000Z
N-body simulations of dark matter halos show that the density is cusped near the center of the halo. The density profile behaves as $r^{-\\gamma}$ in the inner parts, where $\\gamma \\simeq 1$ for the NFW model and $\\gamma \\simeq 1.5$ for the Moore's model, but in the outer parts, both models agree with each other in the asymptotic behavior of the density profile. The simulations also show the information about anisotropy parameter $\\beta(r)$ of velocity distribution. $\\beta\\approx 0$ in the inner part and $\\beta\\approx 0.5$ (radially anisotropic) in the outer part of the halo. We provide some distribution functions $F(E,L)$ with the constant anisotropy parameter $\\beta$ for the two spherical models of dark matter halos: a new generalized NFW model and a generalized Moore model. There are two parameters $\\alpha$ and $\\epsilon$ for those two generalized models to determine the asymptotic behavior of the density profile. In this paper, we concentrate on the situation of $\\beta(r)=1/2$ from the viewpoint of the simulation.
Spectroscopic constants and potential energy curves of tungsten carbide
Balasubramanian, K. [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604 (United States)] [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604 (United States)
2000-05-01T23:59:59.000Z
Spectroscopic constants (R{sub e},{omega}{sub e},T{sub e},{mu}{sub e}) and potential energy curves for 40 low-lying electronic states of the diatomic tungsten carbide (WC) were obtained using the complete active space multiconfiguration self-consistent field followed by the multireference singles+doubles configuration interaction and full first- and second-order configuration interaction calculations that included up to 6.4 mil configurations. Spin-orbit effects were included through the enhanced relativistic configuration interaction method described here for 28 electronic states of WC lying below {approx}20 000 cm-1. The spin-orbit splitting of the ground state of WC was found to be very large (4394 cm-1). The ground and excited electronic states of the W atom were also computed and were found to be in good agreement with the experimental data. The nature of bonding was analyzed through the composition of orbitals, leading configurations, Mulliken populations, and dipole moments. The dissociation energy of WC was computed including spin-orbit and electron correlation effects. The recent photoelectron spectra of WC{sup -} were assigned on the basis of our computed results. (c) 2000 American Institute of Physics.
Toward a sub-ppm measurement of the Fermi constant
David M. Webber
2010-06-21T23:59:59.000Z
The Fermi constant, G_F, describes the strength of the weak force and is determined most precisely from the mean life of the positive muon, tau_mu. Advances in theory have reduced the theoretical uncertainty on G_F as calculated from tau_mu to a few tenths of a part per million (ppm). The remaining uncertainty on G_F is entirely experimental, and is dominated by the uncertainty on tau_mu. The MuLan experiment is designed to measure the muon lifetime to part-per-million precision, a better-than twenty-fold improvement over the previous generation of experiments. In 2007, we reported an intermediate result, tau_mu=2.197013(24) microseconds (11 ppm), which is in excellent agreement with the previous world average. This mean life was measured using a pulsed surface muon beam stopped in a ferromagnetic target, surrounded by a symmetric scintillator detector array. Since this intermediate measurement, the detector was instrumented with waveform digitizers, the muon beam rate and beam extinction were increased, and two data sets were acquired on different targets, each containing over 10^12 muon decays. These data will lead to a new determination of G_F to better than a part per million.
TYPES OF NONIMMIGRANT VISAS Type Description
for pleasure and cannot receive any type of payments. C-1*, Aliens in travel status while travelling directly through the C-2*, United States. C-3* D-1 Alien crewman on shore leave or transferring to another vessel is grounds for deportation. E-1 Aliens who conduct trade or inventories between the United States
Testable solution of the cosmological constant and coincidence problems
Shaw, Douglas J.; Barrow, John D. [DAMTP, Centre for Mathematical Sciences, Cambridge CB3 0WA (United Kingdom)
2011-02-15T23:59:59.000Z
We present a new solution to the cosmological constant (CC) and coincidence problems in which the observed value of the CC, {Lambda}, is linked to other observable properties of the Universe. This is achieved by promoting the CC from a parameter that must be specified, to a field that can take many possible values. The observed value of {Lambda}{approx_equal}(9.3 Gyrs){sup -2}[{approx_equal}10{sup -120} in Planck units] is determined by a new constraint equation which follows from the application of a causally restricted variation principle. When applied to our visible Universe, the model makes a testable prediction for the dimensionless spatial curvature of {Omega}{sub k0}=-0.0056({zeta}{sub b}/0.5), where {zeta}{sub b}{approx}1/2 is a QCD parameter. Requiring that a classical history exist, our model determines the probability of observing a given {Lambda}. The observed CC value, which we successfully predict, is typical within our model even before the effects of anthropic selection are included. When anthropic selection effects are accounted for, we find that the observed coincidence between t{sub {Lambda}={Lambda}}{sup -1/2} and the age of the Universe, t{sub U}, is a typical occurrence in our model. In contrast to multiverse explanations of the CC problems, our solution is independent of the choice of a prior weighting of different {Lambda} values and does not rely on anthropic selection effects. Our model includes no unnatural small parameters and does not require the introduction of new dynamical scalar fields or modifications to general relativity, and it can be tested by astronomical observations in the near future.
Velocity Dispersions Across Bulge Types
Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich [University Observatory of the Ludwig-Maximilians University (LMU) (Germany); Max-Planck Institute for Extraterrestrial Physics (MPE) (Germany); Saglia, Roberto; Drory, Niv [Max-Planck Institute for Extraterrestrial Physics (MPE) (Germany); Fisher, David [Department of Astronomy, University of Texas at Austin (United States)
2010-06-08T23:59:59.000Z
We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (sigma*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.
A Constant Spectral Index for Sagittarius A* During Infrared/X-ray Intensity Variations
S. D. Hornstein; K. Matthews; A. M. Ghez; J. R. Lu; M. Morris; E. E. Becklin; M. Rafelski; F. K. Baganoff
2007-06-12T23:59:59.000Z
We report the first time-series of broadband infrared (IR) color measurements of Sgr A*, the variable emission source associated with the supermassive black hole at the Galactic Center. Using the laser and natural guide star AO systems on the Keck II telescope, we imaged Sgr A* in multiple near-infrared broadband filters with a typical cycle time of ~3 min during 4 observing runs (2005-2006), two of which were simultaneous with Chandra X-ray measurements. In spite of the large range of dereddened flux densities for Sgr A* (2-30 mJy), all of our near-IR measurements are consistent with a constant spectral index of alpha = -0.6+-0.2. Furthermore, this value is consistent with the spectral indices observed at X-ray wavelengths during nearly all outbursts; which is consistent with the synchrotron self-Compton model for the production of the X-ray emission. During the coordinated observations, one IR outburst occurs 1 GeV is generated, and it is this high-energy tail that gives rise to the X-ray outbursts. One possible explanation for this type of variation is from the turbulence induced by a magnetorotational instability, in which the outer scale length of the turbulence varies and changes the high-energy cutoff.
Wightman function and the Casimir effect for a Robin sphere in a constant curvature space
S. Bellucci; A. A. Saharian; N. A. Saharyan
2014-07-03T23:59:59.000Z
We evaluate the Wightman function, the mean field squared and the vacuum expectation value (VEV) of the energy-momentum tensor for a scalar field with Robin boundary condition on a spherical shell in the background of a constant negative curvature space. For the coefficient in the boundary condition there is a critical value above which the scalar vacuum becomes unstable. In both interior and exterior regions, the VEVs are decomposed into the boundary-free and sphere-induced contributions. For the latter, rapidly convergent integral representations are provided. In the region inside the sphere, the eigenvalues are expressed in terms of the zeros of the combination of the associated Legendre function and its derivative and the decomposition is achieved by making use of the Abel-Plana type summation formula for the series over these zeros. The sphere-induced contribution to the VEV of the field squared is negative for Dirichlet boundary condition and positive for Neumann one. At distances from the sphere larger than the curvature scale of the background space the suppression of the vacuum fluctuations in the gravitational field corresponding to the negative curvature space is stronger compared with the case of the Minkowskian bulk. In particular, the decay of the VEVs with the distance is exponential for both massive and massless fields. The corresponding results are generalized for spaces with spherical bubbles and for cosmological models with negative curvature spaces.
Your Guide to Diabetes: Type 1 and Type 2
Rau, Don C.
Your Guide to Diabetes: Type 1 and Type 2 National Diabetes Information Clearinghouse #12;#12;Your Guide to Diabetes: Type 1 and Type 2 #12;#12;Contents Learn about Diabetes ............................................................ 1 What is diabetes? .............................................................. 2 What
DTERMINATION DES CONSTANTES SCALAIRES DE L'TAT DE BASE DE SF6
Paris-Sud XI, Université de
L-373 DÉTERMINATION DES CONSTANTES SCALAIRES DE L'ÉTAT DE BASE DE SF6 H. BERGER, A. ABOUMAJD et R'analyse de la bande Raman 03BD2 de SF6, les constantes scalaires de l'état de base ont pu être déterminéesBD2 Raman band the molecular constants of the ground state of SF6 have been determined : B0 = 0
On the Running of the Cosmological Constant in Quantum General Relativity
B. F. L. Ward
2009-08-12T23:59:59.000Z
We present arguments that show what the running of the cosmological constant means when quantum general relativity is formulated following the prescription developed by Feynman.
Layered Copper-Based Electrode for High-Dielectric Constant Oxide...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Copper-Based Electrode for High-Dielectric Constant Oxide Thin-Film-Based Devices Technology available for licenisng: A multilayer thin-film device containing copper layers...
Cosmological Constant as Vacuum Energy Density of Quantum Field Theories on Noncommutative Spacetime
Xiao-Jun Wang
2004-12-15T23:59:59.000Z
We propose a new approach to understand hierarchy problem for cosmological constant in terms of considering noncommutative nature of space-time. We calculate that vacuum energy density of the noncommutative quantum field theories in nontrivial background, which admits a smaller cosmological constant by introducing an higher noncommutative scale $\\mu_{NC}\\sim M_p$. The result $\\rho_\\Lambda\\sim 10^{-6}\\Lambda_{SUSY}^8M_p^4/\\mu_{NC}^8$ yields cosmological constant at the order of current observed value for supersymmetry breaking scale at 10TeV. It is the same as Banks' phenomenological formula for cosmological constant.
Elastic Constants of Ni-Mn-Ga Magnetic Shape Memory Alloys
Stipcich, M. [Universitat de Barcelona; Manosa, L. [Universitat de Barcelona; Planes, A. [Universitat de Barcelona; Morin, M. [INSA de Lyon; Zarestky, Jerel L [ORNL; Lograsso, Tom [Ames Laboratory; Stassis, C. [Ames Laboratory
2004-01-01T23:59:59.000Z
We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in any of the elastic constants has been observed at the Curie point. The temperature dependence of the shear elastic constant C' has been found to be very different for the two alloys. Such a different behavior is in agreement with recent theoretical predictions for systems undergoing multi-stage structural transitions.
Mitroi, F C
2011-01-01T23:59:59.000Z
The aim of this paper is to present some new Fejer-type results for convex functions. Improvements of Young's inequality (the arithmetic-geometric mean inequality) and other applications to special means are pointed as well.
Froissart Bound on Inelastic Cross Section Without Unknown Constants
Martin, André
2015-01-01T23:59:59.000Z
Assuming that axiomatic local field theory results hold for hadron scattering, Andr\\'e Martin and S. M. Roy recently obtained absolute bounds on the D-wave below threshold for pion-pion scattering and thereby determined the scale of the logarithm in the Froissart bound on total cross sections in terms of pion mass only. Previously, Martin proved a rigorous upper bound on the inelastic cross-section $\\sigma_{inel}$ which is one-fourth of the corresponding upper bound on $\\sigma_{tot}$, and Wu, Martin,Roy and Singh improved the bound by adding the constraint of a given $\\sigma_{tot}$. Here we use unitarity and analyticity to determine, without any high energy approximation, upper bounds on energy averaged inelastic cross sections in terms of low energy data in the crossed channel. These are Froissart-type bounds without any unknown coefficient or unknown scale factors and can be tested experimentally. Alternatively, their asymptotic forms,together with the Martin-Roy absolute bounds on pion-pion D-waves below t...
THE LIND-LEHMER CONSTANT FOR Zn DILUM DESILVA AND CHRISTOPHER PINNER
Pinner, Christopher
THE LIND-LEHMER CONSTANT FOR Zn p DILUM DESILVA AND CHRISTOPHER PINNER Abstract. We determine the Lind Lehmer constant for groups of the form Zn p . 1. Introduction Let G be a compact abelian group of integral combinations of characters, Lind [6] defines a logarithmic Mahler measure of f over G m(f) = m
Truong, Thanh N.
of a focusing technique to minimize the number of electronic structure calculations, while still preservingA direct ab inifio dynamics approach for calculating thermal rate constants using variational dynamics, " for calculations of thermal rate constants and related properties from first principles
DETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME
Hart, Gus
deposition and characterization of reactively-sputtered uranium nitride thin films. I also report opticalDETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME ULTRAVIOLET (1.6-35 NM.1 Application 1 1.2 Optical Constants 2 1.3 Project Focus 7 2 Uranium Nitride Thin Films 8 2.1 Sputtering 8 2
Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy
Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy reactions in which the product recoil energy is assumed constant (CPR approximation). It is further assumed that the reaction probability is independent ofboth the impact parameter and the collision energy for all collisions
Universal Gravitational Constant EX-9908 Page 1 of 13 Re-Written by Geoffrey R. Clarion
Dai, Pengcheng
Newton was able to deduce his law of universal gravitation. Newton's law of universal gravitation: 2 21 rUniversal Gravitational Constant EX-9908 Page 1 of 13 Re-Written by Geoffrey R. Clarion Universal Gravitational Constant EQUIPMENT 1 Gravitational Torsion Balance AP-8215 1 X-Y Adjustable Diode Laser OS-8526A 1
Liu, Yijun
A fast multipole boundary element method for modeling 2-D multiple crack problems with constant 3 April 2014 Accepted 20 May 2014 Keywords: Fast multipole BEM 2-D multi-crack problems Constant elements Crack opening displacements Stress intensity factors a b s t r a c t A fast multipole boundary
THE PURIFICATION OF SF6 IN A CONSTANT TEMPERATURE ADSORPTION PROCESS
Boyer, Edmond
1423 THE PURIFICATION OF SF6 IN A CONSTANT TEMPERATURE ADSORPTION PROCESS C. BRASSARD Laboratoire propagation du SF6 dû à son adsorption dans une colonne de charbon actif à une tempéra- ture constante de 2014 20 °C. Abstract. 2014 The Dynamitron and the Tandem SF6 gas, initially contained 11 % and 35 % non
Evolution of the coupling constant in SU(2) lattice gauge theory with two adjoint fermions
Ari J. Hietanen; Kari Rummukainen; Kimmo Tuominen
2009-11-24T23:59:59.000Z
We measure the evolution of the coupling constant using the Schroedinger functional method in the lattice formulation of SU(2) gauge theory with two massless Dirac fermions in the adjoint representation. We observe strong evidence for an infrared fixed point, where the theory becomes conformal. We measure the continuum beta-function and the coupling constant as a function of the energy scale.
Sezgin, Metin
2006-01-01T23:59:59.000Z
in the binary expansions of Feigenbaum constants a and d for the logistic map. The analysis is carried out constants; Normal numbers; Random number generation; Statistical analysis In a recent article Karamanos their conclusions. For example in the first table the calculated w2 value is 1.421 as stated. But this value fails
Direct Test of the Time-Independence of Fundamental Nuclear Constants Using the Oklo
Shlyakhter, Ilya
Direct Test of the Time-Independence of Fundamental Nuclear Constants Using the Oklo Natural Reactor #3; Alexander I. Shlyakhter November 18, 1982 1 Introduction The following eight quantities enter the important natural constants of cosmology and atomic theory are connected by simple mathematical relations
Performance of W4 theory for spectroscopic constants and electrical properties of small molecules
Martin, Jan M.L.
Performance of W4 theory for spectroscopic constants and electrical properties of small molecules Accurate spectroscopic constants and electrical properties of small molecules are determined by means of W4 and post-W4 theories. For a set of 28 first- and second-row diatomic molecules for which very accurate
Statistics of Landscapes Based on Free Energies, Replication and Degradation Rate Constants of
Stadler, Peter F.
Statistics of Landscapes Based on Free Energies, Replication and Degradation Rate Constants of RNA are computed from primary sequences by means of a folding algorithm which uses a minimum free energy criterion. Free energies as well as replication and degradation rate constants are derived from secondary
The Asymptotic Minimax Constant for Sup-Norm Loss in Nonparametric Density Estimation
Nussbaum, Michael
The Asymptotic Minimax Constant for Sup-Norm Loss in Nonparametric Density Estimation ALEXANDER, uniform nor- m risk, white noise RUNNING TITLE: Asymptotic minimax density estimation To whom) an asymptotically minimax exact constant has been found for loss in the uniform norm, for Gaussian nonparametric
Controllable giant dielectric constant in AlO{sub x}/TiO{sub y} nanolaminates.
Li, W.; Chen, Z.; Premnath, R. N.; Kabius, B.; Auciello, O. (Center for Nanoscale Materials); ( MSD); (Univ. of Puerto Rico)
2011-01-01T23:59:59.000Z
Dielectric materials exhibiting high dielectric constants play critical roles in a wide range of applications from microchip energy storage embedded capacitors for implantable biomedical devices to energy storage capacitors for a new generation of renewable energy generation/storage systems. Instead of searching for new materials, we demonstrate that giant dielectric constants can be achieved by integrating two simple oxides with low dielectric constants into nanolaminate structures. In addition, the obtained dielectric constant values are highly tunable by manipulating the sub-layer thicknesses of the component oxides to control the number of interfaces and oxygen redistribution. The work reported here opens a new pathway for the design and development of high dielectric constant materials based on the nanolaminate concept.
An accurate determination of the Avogadro constant by counting the atoms in a 28Si crystal
Andreas, B; Bartl, G; Becker, P; Bettin, H; Borys, M; Busch, I; Gray, M; Fuchs, P; Fujii, K; Fujimoto, H; Kessler, E; Krumrey, M; Kuetgens, U; Kuramoto, N; Mana, G; Manson, P; Massa, E; Mizushima, S; Nicolaus, A; Picard, A; Pramann, A; Rienitz, O; Schiel, D; Valkiers, S; Waseda, A
2010-01-01T23:59:59.000Z
The Avogadro constant links the atomic and the macroscopic properties of matter. Since the molar Planck constant is well known via the measurement of the Rydberg constant, it is also closely related to the Planck constant. In addition, its accurate determination is of paramount importance for a definition of the kilogram in terms of a fundamental constant. We describe a new approach for its determination by "counting" the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope. It enabled isotope dilution mass spectroscopy to determine the molar mass of the silicon crystal with unprecedented accuracy. The value obtained, 6.02214084(18) x 10^23 mol^-1, is the most accurate input datum for a new definition of the kilogram.
Jiang, Xikai [ORNL] [ORNL; Huang, Jingsong [ORNL] [ORNL; Zhao, Hui [University of Nevada, Las Vegas] [University of Nevada, Las Vegas; Sumpter, Bobby G [ORNL] [ORNL; Qiao, Rui [Clemson University] [Clemson University
2014-01-01T23:59:59.000Z
We report detailed simulation results on the formation dynamics of an electrical double layer (EDL) inside an electrochemical cell featuring room-temperature ionic liquids (RTILs) enclosed between two planar electrodes. Under relatively small charging currents, the evolution of cell potential during charging can be suitably predicted by the Landau-Ginzburg-type continuum model proposed recently (M. Z. Bazant, B. D. Storey, and A. A. Kornyshev, Phys. Rev. Lett., 106, 046102, 2011). Under very large charging currents, the cell potential shows pronounced oscillation during the initial stage of charging, a feature not captured by the continuum model. Such oscillation originates from the sequential growth of the ionic space charge layers near the electrode surface, allowing the evolution of EDLs in RTILs with time, an atomistic process difficult to visualize experimentally, to be studied by analyzing the cell potential under constant current charging conditions. While the continuum model cannot predict the potential oscillation under such far-from-equilibrium charging conditions, it can nevertheless qualitatively capture the growth of cell potential during the later stage of charging. Improving the continuum model by introducing frequency-dependent dielectric constant and density-dependent ion diffusion coefficients may help to further extend the applicability of the model. Keywords: ionic
Katsuda, Satoru [RIKEN (The Institute of Physical and Chemical Research) Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nozawa, Takaya [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Pooley, David [Department of Physics, Sam Houston State University, Huntsville, TX 77341-2267 (United States); Immler, Stefan [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 2077 (United States)
2014-01-10T23:59:59.000Z
We report on the X-ray spectral evolution of the nearby Type IIn supernova (SN) 2005ip based on Chandra and Swift observations covering ?1-6 yr after explosion. X-ray spectra in all epochs are well fitted by a thermal emission model with kT ? 7 keV. The somewhat high temperature suggests that the X-ray emission mainly arises from the circumstellar medium (CSM) heated by the forward shock. We find that the spectra taken two to three years after the explosion are heavily absorbed (N {sub H} ? 5 × 10{sup 22} cm{sup –2}), but the absorption gradually decreases to the level of the Galactic absorption (N {sub H} ? 4 × 10{sup 20} cm{sup –2}) at the final epoch. This indicates that the SN went off in a dense CSM and that the forward shock has overtaken it. The intrinsic X-ray luminosity stays constant until the final epoch, when it drops by a factor of ?2. The intrinsic 0.2-10 keV luminosity during the plateau phase is measured to be ?1.5 × 10{sup 41} erg s{sup –1}, ranking SN 2005ip as one of the brightest X-ray SNe. Based on the column density, we derive a lower limit of a mass-loss rate to be M-dot ?1.5×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, which roughly agrees with that inferred from the X-ray luminosity, M-dot ?2×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, where V{sub w} is the circumstellar wind speed. Such a high mass-loss rate suggests that the progenitor star had eruptive mass ejections similar to a luminous blue variable star. The total mass ejected in the eruptive period is estimated to be ?15 M {sub ?}, indicating that the progenitor mass is ? 25 M {sub ?}.
Window Types | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
aluminum or vinyl cladding reduces maintenance requirements. Types of Window Glazing or Glass In addition to choosing a frame type, you will need to consider what type of glazing...
Practical pluggable types for Java
Papi, Matthew M
2008-01-01T23:59:59.000Z
This paper introduces the Checker Framework, which supports adding pluggable type systems to the Java language in a backward-compatible way. A type system designer defines type qualifiers and their semantics, and a compiler ...
Leptonic B- and D-meson decay constants with 2+1 flavors of asqtad fermions
Andreas S. Kronfeld; Ethan T. Neil; James N. Simone; Ruth S. Van de Water; for the Fermilab Lattice Collaboration; for the MILC Collaboration
2015-01-08T23:59:59.000Z
We present the status of our updated D- and B-meson decay-constant analysis, based on the MILC $N_f = 2+1$ asqtad gauge ensembles. Heavy quarks are incorporated using the Wilson clover action with the Fermilab interpretation. This analysis includes ensembles at five lattice spacings from a $\\approx$ 0.045 to 0.15 fm, and light sea-quark masses down to 1/20th of the strange-quark mass. Projected error budgets for ratios of decay constants, in particular between bottom- and charm-meson decay constants, are presented.
B and D meson decay constants from 2+1 flavor improved staggered simulations
E. T. Neil; Jon A. Bailey; A. Bazavov; C. Bernard; C. M. Bouchard; C. DeTar; M. Di Pierro; A. X. El-Khadra; R. T. Evans; E. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; R. Jain; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; for the Fermilab Lattice Collaboration; for the MILC Collaboration
2011-12-16T23:59:59.000Z
We give an update on simulation results for the decay constants f_B, f_{B_s}, f_D and f_{D_s}. These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity triangle fit. The results presented here make use of the MILC (2+1)-flavor asqtad ensembles, with heavy quarks incorporated using the clover action with the Fermilab method. Partially quenched, staggered chiral perturbation theory is used to extract the decay constants at the physical point. In addition, we give error projections for a new analysis in progress, based on an extended data set.
Decay constants of the pion and its excitations on the lattice.
Mastropas, Ekaterina V. [William and Mary College, JLAB; Richards, David G. [JLAB
2014-07-01T23:59:59.000Z
We present a calculation using lattice QCD of the ratios of decay constants of the excited states of the pion, to that of the pion ground state, at three values of the pion mass between 400 and 700 MeV, using an anisotropic clover fermion action with three flavors of quarks. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass. The strong suppression of the decay constant of the second excited state is consistent with its interpretation as a predominantly hybrid state.
Towards a consistent estimate of the chiral low-energy constants
V. Cirigliano; G. Ecker; M. Eidemuller; R. Kaiser; A. Pich; J. Portoles
2006-07-17T23:59:59.000Z
Guided by the large-Nc limit of QCD, we construct the most general chiral resonance Lagrangian that can generate chiral low-energy constants up to O(p^6). By integrating out the resonance fields, the low-energy constants are parametrized in terms of resonance masses and couplings. Information on those couplings and on the low-energy constants can be extracted by analysing QCD Green functions of currents both for large and small momenta. The chiral resonance theory generates Green functions that interpolate between QCD and chiral perturbation theory. As specific examples we consider the VAP and SPP Green functions.
Dust around Type Ia supernovae
Wang, Lifan
2005-01-01T23:59:59.000Z
Dust around Type Ia supernovae Lifan Wang 1,2 LawrenceIa. Subject headings: Supernovae: General, Dust, Extinctionline) bands for Type Ia supernovae. (a), upper panel, shows
Rappels: 4) Piles Types abstraits de donnes (Abstract Data Type)
Hamel, Sylvie
Rappels: 4) Piles #12;Types abstraits de données (Abstract Data Type) IFT2015, A2009, Sylvie Hamel Université de Montréal 1Piles Type de données Un ensemble de valeurs Un ensemble d'opérations Structure de Université de Montréal 2Piles #12;Type abstrait de données PILE (§4.2) Garde en mémoire des objets
The Gravitational Instability of the Vacuum: Insight into the Cosmological Constant Problem
Alexander, S
2004-07-06T23:59:59.000Z
A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The coupling of the fermions to the gravitational field generates fermion condensates with zero momentum and a phase transition induces a nonperturbative transition to a true vacuum state by producing a positive energy gap {Delta} in the vacuum energy, identified with {radical}{Lambda}, where {Lambda} is the cosmological constant. In the strong coupling limit a large cosmological constant induces a period of inflation in the early universe, followed by a weak coupling limit in which {radical}{Lambda} vanishes exponentially fast as the universe expands due to the dependence of the energy gap on the density of Fermi surface fermions, D({epsilon}), predicting a small cosmological constant in the present universe.
Research on Fuzzy Regulation Strategies in the Constant Air Volume Air Conditioning System
Bai, T.; Zhang, J.; Ning, N.; Tong, K.; Wu, Y.; Wang, H.
2006-01-01T23:59:59.000Z
The energy consumption of the constant air volume (CAV) system largely depends on the regulation strategies. Although some air conditioning systems are equipped with automatic regulation devices, others lack effective regulation strategies. To avoid...
Al-Asaad, Hussain
1 ABSTRACT Microprocessors are becoming increasingly complex and difficult to debug. Researchers are constantly looking for new methods to increase the observability and control- lability of microprocessors to important internal signals without inter- rupting the microprocessor execution. The output
A new scheme for the running coupling constant in gauge theories using Wilson loops
Erek Bilgici; Antonino Flachi; Etsuko Itou; Masafumi Kurachi; C. -J David Lin; Hideo Matsufuru; Hiroshi Ohki; Tetsuya Onogi; Takeshi Yamazaki
2010-01-21T23:59:59.000Z
We propose a new renormalization scheme of the running coupling constant in general gauge theories using the Wilson loops. The renormalized coupling constant is obtained from the Creutz ratio in lattice simulations and the corresponding perturbative coefficient at the leading order. The latter can be calculated by adopting the zeta-function resummation techniques. We perform a benchmark test of our scheme in quenched QCD with the plaquette gauge action. The running of the coupling constant is determined by applying the step-scaling procedure. Using several methods to improve the statistical accuracy, we show that the running coupling constant can be determined in a wide range of energy scales with relatively small number of gauge configurations.
A constant-mass fuel delivery system for use in underwater autonomous vehicles
Saxton-Fox, Theresa Ann
2012-01-01T23:59:59.000Z
This thesis describes the design and assembly of two constant-mass fuel tanks to be used in autonomous underwater vehicles (AUVs). The fuel tanks are part of a power supply designed to increase AUV endurance without limiting ...
Sack, Jean H. (Jean Hope)
2013-01-01T23:59:59.000Z
The purpose of this thesis was to construct and seal air and containment tanks and other parts for a constant buoyancy power supply for an Autonomous Underwater Vehicle, or AUV. While multiple materials and techniques were ...
Universe Decay, Inflation and the Large Eigenvalue of the Cosmological Constant Seesaw
Michael McGuigan
2007-02-22T23:59:59.000Z
We discuss implications of the large eigenvalue of the cosmological constant seesaw mechanism extending hep-th/0602112 and hep-th/0604108. While the previous papers focused on the small eigenvalue as a cosmological constant associated with the accelerating Universe, here we draw attention to the physical implications of the large eigenvalue. In particular we find that the large eigenvalue can give rise to a period of inflation terminated by Universe decay. The mechanism involves quantum tunneling and mixing and introduces parameters $\\Gamma$, the decay constant, and $\\theta$, the mixing angle. We discuss the cosmological constant seesaw mechanism in the context of various models of current interest including chain inflation, inflatonless inflation, string theory, Universe entanglement and different approaches to the hierarchy problem.
Study of Thermal Properties of Graphene-Based Structures Using the Force Constant Method
Study of Thermal Properties of Graphene-Based Structures Using the Force Constant Method Hossein, 2012) Abstract The thermal properties of graphene-based materials are theoretically investigated transport is investigated for different structures including graphene, graphene antidot lat- tices
CODATA recommended values of the fundamental physical constants: Peter J. Mohr
, People's Republic of China Electronic address: mohr@nist.gov Electronic address: barry.taylor@nist.gov be found on the World Wide Web at physics.nist.gov/constants. CONTENTS Glossary 3 I. Introduction 5 A
AbstractStock-rebuilding time iso pleths relate constant levels of fishing
519 AbstractStock-rebuilding time iso pleths relate constant levels of fishing mortality (F. Iso pleths calculated in previous studies by deterministic models approximate median, rather than mean
On Possible Causes of Divergencies in Experimental Values of Gravitational Constant
A. L. Dmitriev
2006-10-31T23:59:59.000Z
It is shown that discrepancies in the experimental values of the gravitational constant might be caused by the temperature dependence of the gravitational force and inequality of the absolute temperatures of sample masses used in various gravitational experiments.
Optimality gap of constant-order policies decays exponentially in the ...
2014-09-07T23:59:59.000Z
demand, we further compute all expressions appearing in our bound in closed .... positive lead times, sometimes the best constant-order policy outperforms the ..... bounds tight enough to be useful in practice. ...... and consumer responses.
An alternative to constant rate link padding for the prevention of traffic analysis
Graham, Bryan Wayne
2002-01-01T23:59:59.000Z
approach to prevent traffic analysis has always been constant rate link padding. However, the effectiveness of this method when an adversary has access to advanced monitoring equipment and knowledge of statistical analysis has not been addressed...
THE LIND-LEHMER CONSTANT FOR CYCLIC GROUPS OF ORDER LESS THAN 892, 371, 480.
Pinner, Christopher
THE LIND-LEHMER CONSTANT FOR CYCLIC GROUPS OF ORDER LESS THAN 892, 371, 480. VINCENT PIGNO AND CHRISTOPHER PINNER Abstract. We determine the Lind Lehmer constant for the cyclic group Zn when n is not a multiple of 892, 371, 480 = 23 Â· 3 Â· 5 Â· 7 Â· 11 Â· 13 Â· 17 Â· 19 Â· 23. 1. Introduction In [4] Lind introduced
Limits on the integration constant of the dark radiation term in Brane Cosmology
A. S. Al-Rawaf
2005-05-25T23:59:59.000Z
We consider the constraints from primordial Helium abundances on the constant of integration of the dark radiation term of the brane-world generalized Friedmann equation derived from the Randall-Sundrum Single brane model. We found that -- using simple, approximate and semianalytical Method -- that the constant of integration is limited to be between -8.9 and 2.2 which limits the possible contribution from dark radiation term to be approximately between -27% to 7% of the background photon energy density.
Variation of jet quenching from RHIC to LHC and thermal suppression of QCD coupling constant
B. G. Zakharov
2011-05-10T23:59:59.000Z
We perform a joint jet tomographic analysis of the data on the nuclear modification factor $R_{AA}$ from PHENIX at RHIC and ALICE at LHC. The computations are performed accounting for radiative and collisional parton energy loss with running coupling constant. Our results show that the observed slow variation of $R_{AA}$ from RHIC to LHC indicates that the QCD coupling constant is suppressed in the quark-gluon plasma produced at LHC.
Millimet, Scott Alan
1982-01-01T23:59:59.000Z
THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKET NG SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Ma) or Subject: Agricultural Economics THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKETING SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Approved as to style...
Constants of geodesic motion in higher-dimensional black-hole spacetimes
Krtous, Pavel [Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Kubiznak, David [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Page, Don N. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Vasudevan, Muraari [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); JLR Engineering, 111 SE Everett Mall Way, E-201, Everett, Washington 98208-3236 (United States)
2007-10-15T23:59:59.000Z
In [Phys. Rev. Lett. 98, 061102 (2007)], we announced the complete integrability of geodesic motion in the general higher-dimensional rotating black-hole spacetimes. In the present paper we prove all the necessary steps leading to this conclusion. In particular, we demonstrate the independence of the constants of motion and the fact that they Poisson commute. The relation to a different set of constants of motion constructed in [J. High Energy Phys. 02 (2007) 004] is also briefly discussed.
On the distribution of estimators of diffusion constants for Brownian motion
Denis Boyer; David S. Dean
2011-07-26T23:59:59.000Z
We discuss the distribution of various estimators for extracting the diffusion constant of single Brownian trajectories obtained by fitting the squared displacement of the trajectory. The analysis of the problem can be framed in terms of quadratic functionals of Brownian motion that correspond to the Euclidean path integral for simple Harmonic oscillators with time dependent frequencies. Explicit analytical results are given for the distribution of the diffusion constant estimator in a number of cases and our results are confirmed by numerical simulations.
Variation of calibration constant of alpha track detectors with respect to altitude
Vasudevan, Latha
1991-01-01T23:59:59.000Z
and earthquake prediction (Fleischer et al. 1980). A number of methods for monitoring radon gas concentrations in air have been developed in recent years. They encompass a variety of experimental techniques with a wide range of sensitivities and time... of the calibration constant is essential for the reliable determination of indoor air concentration and other applications of the Alpha Track Detector (ATD) measurements. The calibration constant was derived from the observed track densities (tracks/cm') for each...
Millimet, Scott Alan
1982-01-01T23:59:59.000Z
THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKET NG SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Ma) or Subject: Agricultural Economics THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKETING SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Approved as to style...
Null-plane phenomenology for the pion decay constant and radius
Frederico, T.; Miller, G.A. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))
1992-06-01T23:59:59.000Z
The pion decay constant and the electromagnetic form factor are computed by using quark diagrams and projecting the bound-state wave function on the null plane. We show that the resulting formulas are the same as those of the Hamiltonian front-form scheme. The connection between the radius ({ital r}{sub {pi}}) and the pion decay constant ({ital f}{sub {pi}}) is studied using different models of confinement.
Optimal transport of two ions under slow spring-constant drifts
Xiao-Jing Lu; Mikel Palmero; Andreas Ruschhaupt; Xi Chen; Juan Gonzalo Muga
2015-02-05T23:59:59.000Z
We investigate the effect of slow spring-constant drifts of the trap used to shuttle two ions of different mass. We design transport protocols to suppress or mitigate the final excitation energy by applying invariant-based inverse engineering, perturbation theory, and a harmonic dynamical normal-mode approximation. A simple, explicit trigonometric protocol for the trap trajectory is found to be robust with respect to the spring-constant drifts.
Spinor Field with Polynomial Nonlinearity in LRS Bianchi type-I spacetime
Bijan Saha
2015-07-22T23:59:59.000Z
Within the scope of Bianchi type-I cosmological model the role of spinor field on the evolution of the Universe is investigated. In doing so we have considered a polynomial type of nonlinearity. It is found that depending on the sign of self-coupling constant the model allows either accelerated mode of expansion or oscillatory mode of evolution. Unlike general Bianchi type-I and Bianchi type $VI_0$ models in this case neither mass term nor the nonlinear term in the Lagrangian of spinor field vanish.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of WntSupportBRAP-focused topicsTwodimensional timeFuel Cells Â» Types
Hasinoff, M D; Azuelos, Georges; Bertl, W; Blecher, M; Chen, C Q; Depommier, P; Doyle, B; Von Egidy, T; Gorringe, T P; Gumplinger, P; Henderson, R; Jonkmans, G; Larabee, A J; MacDonald, J A; McDonald, S C; Munro, M H; Poutissou, J M; Poutissou, R; Robertson, B C; Sample, D G; Schott, W; Taylor, G N; Veillette, S; Wright, D H
1992-01-01T23:59:59.000Z
Determination of the semi-leptonic weak interaction pseudoscalar coupling constant , g$_{P}$, using the reaction $\\mu^{-}$p --> $\
Pluggable type-checking for custom type qualifiers in Java
Papi, Matthew M.
2007-09-17T23:59:59.000Z
We have created a framework for adding custom type qualifiers to the Javalanguage in a backward-compatible way. The type system designer definesthe qualifiers and creates a compiler plug-in that enforces theirsemantics. ...
Rappels: 4) Piles Types abstraits de donnes (Abstract Data Type)
Hamel, Sylvie
Rappels: 4) Piles Types abstraits de donnÃ©es (Abstract Data Type) IFT2015, A2009, Sylvie Hamel UniversitÃ© de MontrÃ©al 1Piles Type de donnÃ©es Un ensemble de valeurs Un ensemble d'opÃ©rations Structure de UniversitÃ© de MontrÃ©al 2Piles Type abstrait de donnÃ©es PILE (Â§4.2) Garde en mÃ©moire des objets arbitraires
Abstract Data Types 5 Algebraic Theory of Abstract Data Types
Berger, Ulrich
stack top: stack elts The following is an algebra for the signature STACK. Algebra SeqN Carriers N, N43 Part II Abstract Data Types #12;44 5 Algebraic Theory of Abstract Data Types An Abstract Data Type (ADT) is a collection of objects and functions, that is, an algebra, where one ignores how
Vail, III, William Banning (Bothell, WA)
2000-01-01T23:59:59.000Z
Methods of operation of different types of multiple electrode apparatus vertically disposed in a cased well to measure information related to the resistivity of adjacent geological formations from within the cased well are described. The multiple electrode apparatus has a minimum of two spaced apart voltage measurement electrodes that electrically engage a first portion of the interior of the cased well and that provide at least first voltage information. Current control means are used to control the magnitude of any selected current that flows along a second portion of the interior of the casing to be equal to a predetermined selected constant. The first portion of the interior of the cased well is spaced apart from the second portion of the interior of the cased well. The first voltage information and the predetermined selected constant value of any selected current flowing along the casing are used in part to determine a magnitude related to the formation resistivity adjacent to the first portion of the interior of the cased well. Methods and apparatus having a plurality of voltage measurement electrodes are disclosed that provide voltage related information in the presence of constant currents flowing along the casing which is used to provide formation resistivity.
Bonnen, C. A.
1960-01-01T23:59:59.000Z
.......... .......-.----------------------. 8 Labor -..-.....-----...------------------------------------------------. 9 Land Tenure .--.----....---....--------------------------------- 9 Number and Size of Farms ....----...----.-._--------- 10 Capital... -------------...-------.---------------------------- 21 Hogs -......-....--------------------------------------------------- 22 Poultry .-.---.-.....--.-..------.---------------------------------- 22 Horses and Mules ---..-....---..--..------------------------ 23 Types of Farming and Type-of-farming...
Predicting the Reactivity of Hydride Donors in Water: Thermodynamic Constants for Hydrogen
Connelly, Samantha J.; Wiedner, Eric S.; Appel, Aaron M.
2015-01-01T23:59:59.000Z
Chemical reactivity of hydride complexes can be predicted by comparing bond strengths for homolytic and heterolytic cleavage of bonds to hydrogen. To determine these bond strengths, thermodynamic constants for H+, H•, H–, and H2 are essential and need to be used uniformly to enable the prediction of reactivity and equilibria. One of the largest challenges is quantifying the stability of solvated H– in water, which is discussed. Due to discrepancies in the literature for the constants used in water, we propose the use of a set of self-consistent constants with convenient standard states. The work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.
Dynamical friction in constant density cores: a failure of the Chandrasekhar formula
J. I. Read; Tobias Goerdt; Ben Moore; A. P. Pontzen; Joachim Stadel; George Lake
2006-10-04T23:59:59.000Z
Using analytic calculations and N-body simulations we show that in constant density (harmonic) cores, sinking satellites undergo an initial phase of very rapid (super-Chandrasekhar) dynamical friction, after which they experience no dynamical friction at all. For density profiles with a central power law profile of log-slope, $-\\alpha$, the infalling satellite heats the background and causes $\\alpha$ to decrease. For $\\alpha < 0.5$ initially, the satellite generates a small central constant density core and stalls as in the $\\alpha = 0$ case. We discuss some astrophysical applications of our results to decaying satellite orbits, galactic bars and mergers of supermassive black hole binaries. In a companion paper we show that a central constant density core can provide a natural solution to the timing problem for Fornax's globular clusters.
Constant-intensity waves and their modulation instability in non-Hermitian potentials
Konstantinos G. Makris; Ziad H. Musslimani; Demetrios N. Christodoulides; Stefan Rotter
2015-03-31T23:59:59.000Z
In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole new class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study, for the first time, the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.
Type Ia Supernova Progenitors, Environmental Effects, and Cosmic Supernova Rates
Ken'ichi Nomoto; Hideyuki Umeda; Izumi Hachisu; Mariko Kato; Chiaki Kobayashi; Takuji Tsujimoto
1999-07-27T23:59:59.000Z
Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting white dwarfs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction $X$(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependence of SNe Ia brighness on the galaxy types. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies.
The runaway instability of thick discs around black holes. II. Non constant angular momentum discs
Frederic Daigne; Jose A. Font
2003-11-28T23:59:59.000Z
We present results from a comprehensive number of relativistic, time-dependent, axisymmetric simulations of the runaway instability of non-constant angular momentum thick discs around black holes. This second paper extends earlier results where only constant angular momentum discs were considered. All relevant aspects of the theory of stationary thick discs around rotating black holes, necessary to build the initial state in our simulations, are presented in great detail. The angular momentum of the discs is assumed to increase outwards with the radial distance according to a power law. The main simplifying assumptions of our approach are not to include magnetic fields and self-gravity in the discs. Furthermore, the dynamics of the spacetime is accounted for by computing the transfer of mass and angular momentum from the disc to the black hole through the event horizon : the evolution of the central black hole is assumed to follow a sequence of Kerr black holes of increasing mass and spin. In agreement with previous results based on stationary models we find that by allowing the mass and the spin of the black hole to grow, constant angular momentum discs rapidly become unstable on a dynamical timescale. The comparison with the results of paper I shows that the effect of the angular momentum transfer from the torus to the black hole is to make constant angular momentum discs less unstable, increasing the timescale of the instability. However, we find that non-constant angular momentum discs are dramatically stabilized for very small values of the angular momentum slope. Our time-dependent simulations confirm, thus, the predictions of stationary studies concerning the stabilizing effect of non-constant angular momentum distributions.
PROGRAMMING WITH TYPES A Dissertation
Weirich, Stephanie
WITH TYPES Stephanie Claudene Weirich, Ph.D. Cornell University 2002 Run-time type analysis, facilities to support type analysis often require complicated language semantics that allow little freedom to list. Steve's parents Arthur and Deborah Zdancewic have encouraged me as long as I have known them. I
Annotated Type Systems Program Analysis
Palsberg, Jens
Danish Summary xi 1 Introduction 1 1.1 The Standard Type System . . . . . . . . . . . . . . . . . 3 1 . . . . . . . . . . . . . . . . . . 36 2.1.3 The Conjunction Type System . . . . . . . . . . . . 37 2.2 The Power of tAnnotated Type Systems for Program Analysis Kirsten Lackner Solberg Computer Science Department
SU(2) chiral fits to light pseudoscalar masses and decay constants
A. Bazavov; C. Bernard; C. DeTar; X. Du; W. Freeman; Steven Gottlieb; Urs M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. B. Oktay; J. Osborn; R. Sugar; D. Toussaint; R. S. Van de Water
2009-11-03T23:59:59.000Z
We present the results of fits to recent asqtad data in the light pseudoscalar sector using SU(2) partially-quenched staggered chiral perturbation theory. Superfine (a~0.06 fm) and ultrafine (a~0.045 fm) ensembles are used, where light sea quark masses and taste splittings are small compared to the strange quark mass. Our fits include continuum NNLO chiral logarithms and analytic terms. We give preliminary results for the pion decay constant, SU(2) low-energy constants and the chiral condensate in the two-flavor chiral limit.
Is the zero-point energy a source of the cosmological constant?
Yasunori Fujii
2014-03-15T23:59:59.000Z
We discuss how we remove a huge discrepancy between the theory of a cosmological constant, due to the zero-point energies of matter fields, and the observation. The technique of dimensional regularization plays a decisive role. We eventually reach the desired behavior of the vacuum densities falling off like t^{-2}, allowing us to understand how an extremely small result comes about naturally. As a price, however, the zero-point energy vacuum fails to act as a true cosmological constant. Its expected role responsible for the observed accelerating universe is then to be inherited by the gravitational scalar field, dark energy, as we suggest in the scalar-tensor theory.
Singlet axial-vector coupling constant of the nucleon in QCD without instantons
Janardan P. Singh
2015-07-19T23:59:59.000Z
We have analyzed axial-vector current-current correlation functions between one-nucleon states to calculate the singlet axial-vector coupling constant of the nucleon. The octet-octet and the octet-singlet current correlators, investigated in this work, do not require any use of instanton effects. The QCD and hadronic parameters used for the evaluation of correlators have been varied by (10 - 20)%. The value of the singlet axial-vector coupling constant of the nucleon obtained from this analysis is consistent with its current determination from experiments and QCD theory.
Lattice study of the leptonic decay constant of the pion and its excitations
Mastropas, Ekaterina; Richard, David
2014-11-01T23:59:59.000Z
We present a calculation of the decay constant of the pion, and its lowest-lying three excitations, at three values of the pion mass between around 400 and 700 MeV, using anisotropic clover lattices. We use the variational method to determine an optimal interpolating operator for each of the states. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass.
Information content in $F(R)$ brane models with non-constant curvature
Correa, R A C; Dutra, A de Souza; da Rocha, Roldao; Menezes, R
2015-01-01T23:59:59.000Z
In this work we investigate the entropic information-measure in the context of braneworlds with non-constant curvature. The braneworld entropic information is studied for gravity modified by the squared of the Ricci scalar, besides the usual Einstein-Hilbert term. We showed that the minimum value of the brane configurational entropy provides a stricter bound on the parameter that is responsible for the $F(R)$ model to differ from the Einstein-Hilbert standard one. Our results are moreover consistent to a negative bulk cosmological constant.
Electronic constant current and current pulse signal generator for nuclear instrumentation testing
Brown, Roger A. (Amsterdam, NY)
1994-01-01T23:59:59.000Z
Circuitry for testing the ability of an intermediate range nuclear instrut to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on.
New Phantom and non-Phantom Wormhole Solutions with Generic Cosmological Constant
Heydarzade, Y; Moradpour, H
2014-01-01T23:59:59.000Z
There are a number of reasons to study wormholes with generic cosmological constant $\\Lambda$. Recent observations indicate that present accelerating expansion of the universe demands $\\Lambda>0$. On the other hand, some extended theories of gravitation such as supergravity and superstring theories posses vacuum states with $\\Lambdaenergy density and pressure profiles which support such a geometry are obtained. It is shown that for having such a geometry, the wormhole throat $r_0$, the cosmological constant $\\Lambda$ and the equation of state parameter $\\omega$ sh...
Electronic constant current and current pulse signal generator for nuclear instrumentation testing
Brown, R.A.
1994-04-19T23:59:59.000Z
Circuitry is described for testing the ability of an intermediate range nuclear instrument to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on. 1 figures.
On the Verdet constant and Faraday rotation for graphene-like materials
Mikkel H. Brynildsen; Horia D. Cornean
2013-02-21T23:59:59.000Z
We present a rigorous and rather self-contained analysis of the Verdet constant in graphene- like materials. We apply the gauge-invariant magnetic perturbation theory to a nearest- neighbour tight-binding model and obtain a relatively simple and exactly computable formula for the Verdet constant, at all temperatures and all frequencies of sufficiently large absolute value. Moreover, for the standard nearest neighbour tight-binding model of graphene we show that the transverse component of the conductivity tensor has an asymptotic Taylor expansion in the external magnetic field where all the coefficients of even powers are zero.
Lomboy, Gilson [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, Iowa 50011 (United States); Sundararajan, Sriram, E-mail: srirams@iastate.edu [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States); Wang Kejin [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, Iowa 50011 (United States); Subramaniam, Shankar [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)
2011-11-15T23:59:59.000Z
A method for determining Hamaker constant of cementitious materials is presented. The method involved sample preparation, measurement of adhesion force between the tested material and a silicon nitride probe using atomic force microscopy in dry air and in water, and calculating the Hamaker constant using appropriate contact mechanics models. The work of adhesion and Hamaker constant were computed from the pull-off forces using the Johnson-Kendall-Roberts and Derjagin-Muller-Toropov models. Reference materials with known Hamaker constants (mica, silica, calcite) and commercially available cementitious materials (Portland cement (PC), ground granulated blast furnace slag (GGBFS)) were studied. The Hamaker constants of the reference materials obtained are consistent with those published by previous researchers. The results indicate that PC has a higher Hamaker constant than GGBFS. The Hamaker constant of PC in water is close to the previously predicted value C{sub 3}S, which is attributed to short hydration time ({<=} 45 min) used in this study.
Hsu, Cheng-Ting (Ames, IA)
1984-01-01T23:59:59.000Z
A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.
Marginal evidence for cosmic acceleration from Type Ia supernovae
Nielsen, Jeppe Trøst; Sarkar, Subir
2015-01-01T23:59:59.000Z
The `standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these `standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.
Marginal evidence for cosmic acceleration from Type Ia supernovae
Jeppe Trøst Nielsen; Alberto Guffanti; Subir Sarkar
2015-06-09T23:59:59.000Z
The "standard" model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these "standardisable candles" indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.
A dependent nominal type theory
Cheney, James
2012-01-01T23:59:59.000Z
Nominal abstract syntax is an approach to representing names and binding pioneered by Gabbay and Pitts. So far nominal techniques have mostly been studied using classical logic or model theory, not type theory. Nominal extensions to simple, dependent and ML-like polymorphic languages have been studied, but decidability and normalization results have only been established for simple nominal type theories. We present a LF-style dependent type theory extended with name-abstraction types, prove soundness and decidability of beta-eta-equivalence checking, discuss adequacy and canonical forms via an example, and discuss extensions such as dependently-typed recursion and induction principles.
University of Alberta SafeType: Detecting Type Violations for Type-Based Alias
Amaral, José Nelson
University of Alberta SafeType: Detecting Type Violations for Type-Based Alias Analysis of C Edmonton, Alberta Permission is hereby granted to the University of Alberta Libraries to reproduce single, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other
Sivaramakrishnan, R.; Michael, J. V.; Chemical Sciences and Engineering Division
2009-04-30T23:59:59.000Z
High-temperature rate constant experiments on OH with the five large (C{sub 5}-C{sub 8}) saturated hydrocarbons n-heptane, 2,2,3,3-tetramethylbutane (2,2,3,3-TMB), n-pentane, n-hexane, and 2,3-dimethylbutane (2,3-DMB) were performed with the reflected-shock-tube technique using multipass absorption spectrometric detection of OH radicals at 308 nm. Single-point determinations at {approx}1200 K on n-heptane, 2,2,3,3-TMB, n-hexane, and 2,3-DMB were previously reported by Cohen and co-workers; however, the present work substantially extends the database to both lower and higher temperature. The present experiments span a wide temperature range, 789-1308 K, and represent the first direct measurements of rate constants at T > 800 K for n-pentane. The present work utilized 48 optical passes corresponding to a total path length of {approx}4.2 m. As a result of this increased path length, the high OH concentration detection sensitivity permitted pseudo-first-order analyses for unambiguously measuring rate constants. The experimental results can be expressed in Arrhenius form in units of cm{sup 3} molecule{sup -1} s{sup -1} as follows: K{sub OH+n-heptane} = (2.48 {+-} 0.17) x 10{sup -10} exp[(-1927 {+-} 69 K)/T] (838-1287 K); k{sub OH+2,2,3,3-TMB} = (8.26 {+-} 0.89) x 10{sup -11} exp[(-1337 {+-} 94 K)/T] (789-1061 K); K{sub OH+n-pentane} = (1.60 {+-} 0.25) x 10{sup -10} exp[(-1903 {+-} 146 K)/T] (823-1308 K); K{sub OH+n-hexane} = (2.79 {+-} 0.39) x 10{sup -10} exp[(-2301 {+-} 134 K)/T] (798-1299 K); and k{sub OH+2,3-DMB} = (1.27 {+-} 0.16) x 10{sup -10} exp[(-1617 {+-} 118 K)/T] (843-1292 K). The available experimental data, along with lower-T determinations, were used to obtain evaluations of the experimental rate constants over the temperature range from {approx}230 to 1300 K for most of the title reactions. These extended-temperature-range evaluations, given as three-parameter fits, are as follows: k{sub OH+n-heptane} = 2.059 x 10{sup -5}T{sup 1.401} exp(33 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (241-1287 K); k{sub OH+2,2,3,3-TMB} = 6.835 x 10{sup -17}T{sup 1.886} exp(-365 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (290-1180 K); k{sub OH+n-pentane} = 2.495 x 10{sup -16}T{sup 1.649} exp(80 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (224-1308 K); k{sub OH+n-hexane} = 3.959 x 10{sup -18}T{sup 2.218} exp(443 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (292-1299 K); and k{sub OH+2,3-DMB} = 2.287 x 10{sup -17}T{sup 1.958} exp(365 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (220-1292 K). The experimental data and the evaluations obtained for these five larger alkanes in the present work were used along with prior data/evaluations obtained in this laboratory for H abstractions by OH from a series of smaller alkanes (C{sub 3}?C{sub 5}) to devise rate rules for abstractions from various types of primary, secondary, and tertiary H atoms. Specifically, the current scheme was applied with good success to H abstractions by OH from a series of n-alkanes (n-octane through n-hexadecane). The total rate constants using this group scheme for reactions of OH with selected large alkanes are given as three-parameter fits in this article. The rate constants for the various abstraction channels in any large n-alkane can also be obtained using the groups listed in this article. The present group scheme serves to reduce the uncertainties in rate constants for OH + alkane reactions.
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological constant
Anderson, Michael
Non-trivial, static, geodesically complete, vacuum space-times with a negative solutions of the vacuum Einstein equations with a negative cosmological constant. The new families of this paper is to show that such rigidity is false in this last situation. More precisely, for
Letters to Analytical Chemistry Effects of Constant Voltage on Time Evolution of
Santiago, Juan G.
Letters to Analytical Chemistry Effects of Constant Voltage on Time Evolution of Propagating, California 94305 We extend the analytical theory of propagating concentra- tion polarization (CP) to describe which has a significant influence on analyte concentrations and electric fields in these devices.10
A Constant Gain Kalman Filter Approach to target tracking in Wireless Sensor Networks
Naik, Naren
A Constant Gain Kalman Filter Approach to target tracking in Wireless Sensor Networks Ashwin Yadav1 domains. One of the most fundamen- tal and widely used approaches to target tracking is the Kalman filter. In presence of unknown noise statistics there are difficulties in the Kalman filter yielding good results
Schlegel, H. Bernhard
of Chemistry, Wayne State University, Detroit, Michigan 48202, United States *S Supporting Information ABSTRACT, and cellular death.1-9 Among the canonical nucleobases, guanine is well-known to be the most susceptible at a constant pH of 7 (E7). Redox potentials were obtained by chemical oxidation and kinetic rate measurements
Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment
Unger, L.M.; Trubey, D.K.
1981-09-01T23:59:59.000Z
Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed.
Allouche, Jean-Paul
Algebraic irrational binary numbers cannot be fixed points of nonÂtrivial constant length irrational number in a given base? A common conjectured answer to this vague question is that these digits . A widely believed conjecture is that an algebraic irrational number is a normal number in each base k â?? 2
Spring Constants for Hockey Dan Russell and Linda Hunt, Kettering University, Flint, MI
Russell, Daniel A.
of Static Bending Hockey sticks are rated according to weight, shaft flex, and the amount of curvature- ing the effective spring constant of a hockey stick. The butt end of the shaft is clamped to a rigid bench and masses are hung from a hook at the other end of the shaft where the blade and shaft meet. We
Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen
Spaepen, Frans A.
Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen Division expansion. Viscous flow was measured by stress relaxation and was found to be Newtonian. The viscosity of the viscosity of sputter-deposited samples as a function of stress (to establish the Newtonian charac- ter
Nonholonomic Ricci Flows and Running Cosmological Constant: 3D Taub-NUT Metrics
Sergiu I. Vacaru; Mihai Visinescu
2007-10-11T23:59:59.000Z
The common assertion that the Ricci flows of Einstein spaces with cosmological constant can be modelled by certain classes of nonholonomic frame, metric and linear connection deformations resulting in nonhomogeneous Einstein spaces is examined in the light of the role played by topological three dimensional (3D) Taub-NUT-AdS/dS spacetimes.
Scaling of classical rate constants on scaled potential-energy surfaces Myung Soo Kim,a)
Kim, Myung Soo
or dynamical calculation of a rate constant is to use data from electronic structure calculation. Structure at moderately high levels of electronic structure calculation. © 2001 American Institute of Physics. DOI: 10 state theories and the methods based on classical or quantal dynamics calculation.47 When
Bell, Alexis T.
As ab initio electronic structure calculations become more accurate, inherent sources of error, facilitate reactive flux calculations. As an example we compute the dynamically corrected rate constant on which the reaction occurs. A large number of electronic structure theo- ries are available
Constant Proportion Debt Obligations, Zeno's Paradox, and the Spectacular Financial Crisis of 2008
Richards, Donald St. P.
Constant Proportion Debt Obligations, Zeno's Paradox, and the Spectacular Financial Crisis of 2008-going worldwide financial crisis are heightened by the existence of other financial derivatives more arcane than, to the beat of his dying heart, The Devil drum on the darkened pane: "You did it, but was it Art?" Rudyard
Reid, Scott A.
: Application to ozone formation Mikhail V. Ivanov and Dmitri Babikov Citation: J. Chem. Phys. 136, 184304 (2012 for computing thermal rate constant of recombination: Application to ozone formation Mikhail V. Ivanov of ozone. Comparison of the predicted rate vs. experimental result is presented. © 2012 American Institute
Molenaar, P.; Malta, E.
1986-04-01T23:59:59.000Z
In electrically driven guinea pig left atria, positive inotropic responses to (-)-isoprenaline and the selective beta 1-adrenoceptor agonist RO363 were obtained in the absence and in the presence of the functional antagonists adenosine, carbachol, gallopamil, nifedipine, and Ro 03-7894. Each of the functional antagonists reduced the maximum response to both agonists and produced nonparallel rightward shifts in the cumulative concentration effect curves. For both agonists, dissociation constants (KA) were calculated using the equation described by Furchgott (1966) for irreversible antagonism. For RO363, which is a partial agonist with high agonist activity, the equations outlined for functional interaction by Mackay (1981) were also employed to calculate KA values. The KA values obtained by each method were compared with the dissociation constants (KD) for the two agonists determined from their ability to displace the radioligand (-)-(/sup 125/I)iodocyanopindolol from beta 1-adrenoceptors in guinea pig left atrial membrane preparations. The estimates of KA varied substantially from KD values. The KD values were taken as more accurate estimates of the true values for the dissociation constants because a high degree of correlation exists between pKD and pD2 values for a number of other beta-adrenoceptor agonists that behave as partial agonists and between pKD and pKB values for a number of beta-adrenoceptor antagonists. Thus, it appears that there are serious limitations in the current theory for using functional antagonism as a means of obtaining agonist dissociation constants.
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS
Hauswirth, Laurent
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS L Alexandrov embedded cylinders is explicitly determined. We prove that all embedded cmc tori in the 3-sphere are surfaces of revolution using a combination of integrable systems methods and geometric analysis techniques
Logistic Growth: Quadratic, No Time Delay, K Constant b = [K -N(0)]/N(0)
Caraco, Thomas
Logistic Growth: Quadratic, No Time Delay, K Constant #12;b = [K - N(0)]/N(0) Logistic Population-Cummings Protozoan, small metazoan & large mammal: Logistic growth (app.), Increasing time to max dN/dt #12;Gause, sociology, technology How might logistic growth's assumptions fail biologically? #12;Density
Constant Propagation with Conditional MARK N. WEGMAN and F. KENNETH ZADECK
Cytron, Ron K.
Constant Propagation with Conditional Branches MARK N. WEGMAN and F. KENNETH ZADECK IBM T. J Symposium on Principles of Programming Languages, 1985. Authors' current addresses: Mark N. Wegman, IBM T. J on Programming Languages and Systems, Vol. 13, No. 2, April 1991, Pages 181-210. #12;182 . M. N. Wegman and F. K
Rezwanur Rahman; Douglas K. McCarty; Manika Prasad; John A. Scales
2015-02-13T23:59:59.000Z
We implement a technique to characterize electromagnetic properties at frequencies 100 to 165 GHz (3 cm$^{-1}$ to 4.95 cm$^{-1}$) of oriented montmorillionite samples using an open cavity resonator connected to a sub-millimeter wave VNA (Vector Network Analyzer). We measured dielectric constants perpendicular to the bedding plane on oriented Na$^{+}$ and Ca$^{++}$-ion stabilized montmorillionite samples deposited on a glass slide at ambient laboratory conditions (room temperature and room light). The clay layer is much thinner ($\\sim$ 30 $\\mu$m) than the glass substrate ($\\sim$ 2.18 mm). The real part of dielectric constant,$\\epsilon_{re}$, is essentially constant over this frequency range but is larger in Na$^{+}$- than in Ca$^{++}$-ioned clay. The total electrical conductivity (associated with the imaginary part of dielectric constant, $\\epsilon_{im}$) of both samples increases monotonically at lower frequencies ($$ 110 GHz. The dispersion of the samples display a dependence on the ionic strength in the clay interlayers, i.e., $\\zeta$-potential in the Stern layers.
Time Domain Reflectometry Surface Reflections for Dielectric Constant in Highly Conductive Soils
Nowack, Robert L.
Time Domain Reflectometry Surface Reflections for Dielectric Constant in Highly Conductive Soils reflectometry TDR mea- surement in highly conductive soils. It makes use of information contained in the TDR signal from the reflection at the surface of the soil rather than the reflection from the end
Evaluating the von Kármán Constant in Sediment-laden Air Flow
Li, Bailiang
2012-02-14T23:59:59.000Z
Shear velocity is a critical variable used in many hydrodynamic and aeolian applications. The Law of the Wall is commonly used to derive shear velocity as the product of the slope of a measured velocity profile and the von Kármán constant, ? = 0...
Rubloff, Gary W.
Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems A. J. Zambano,1, * H. Oguchi,1 I. Takeuchi,1 Y. Choi,2,3 J. S. Jiang,2 J. P. Liu,3 S. E December 2006; published 30 April 2007 To elucidate the dependence of exchange coupling behavior of hard/soft
Proofs of Retrievability with Public Verifiability and Constant Communication Cost in Cloud
International Association for Cryptologic Research (IACR)
Proofs of Retrievability with Public Verifiability and Constant Communication Cost in Cloud Jiawei, requires prior specific permission and/or a fee. CloudComputing'13, May 8, 2013, Hangzhou, China. Copyright 2013 ACM 978-1-4503-2067-2/13/05 ...$15.00. Keywords Proofs of Retrievability, Cloud Storage, Public
Overall Rate Constant Measurements of the Reaction of Chloroalkylperoxy Radicals with Nitric Oxide
Elrod, Matthew J.
abundant alkenessethene, propene, 1-butene, 2-butene, 2-methylpropene, 1,3-butadiene, and isoprene (2-methyl-1,3-butadiene)swere determined for the first time via the turbulent flow technique and pseudo, whereas the corresponding rate constants for 1,3-butadiene and isoprene were both 20% higher than
Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics
Jo, Moon-Ho
Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics Moon-Ho Jo aerogel film was characterized from its structural and chemical viewpoints. High porosity of material infrared spectroscopy (FT-IR) for their chemical states. The improved electrical properties of SiO2 aerogel
Determination of Binding Constants of Cyclodextrins in Room-Temperature Ionic Liquids
Reid, Scott A.
unique chemical and physical properties, including being air and moisture stable, a high solubility power with supercritical fluid CO2;9-11 (4) electrochemical reactions;12,13 and (5) as a medium for enzymatic reactions.14Determination of Binding Constants of Cyclodextrins in Room-Temperature Ionic Liquids by Near
Table A1 Molar mass, gas constant, and critical-point properties
Kostic, Milivoje M.
of carbon dioxide, CO2 Table A21 Ideal-gas properties of carbon monoxide, CO Table A22 Ideal Properties of the atmosphere at high altitude Table A17 Ideal-gas properties of air Table A18 Ideal-point properties Molar mass, constant, Temperature, Pressure, Volume, Substance Formula M kg/kmol R kJ/kg·K* K MPa
Miller, William H.
Path integral evaluation of the quantum instanton rate constant for proton transfer in a polar developed by Azzouz and Borgis. Monte Carlo path integral methods are used to carry out the calculations evaluated for comparison using the present path integral approach. A technique is then introduced
Attard, Phil
Calibration of the torsional spring constant and the lateral photodiode response of frictional simultaneously calibrates the photodiode response to the angular deflection of the cantilever. It does not rely and with an independent measurement of the angle calibration. This nondestructive calibration may be performed with any
Relaxation Time Constants and Apparent Diffusion Coefficients of Rat Retina at 7 Tesla
Duong, Timothy Q.
Relaxation Time Constants and Apparent Diffusion Coefficients of Rat Retina at 7 Tesla Govind Nair* and ADC of the rat eyes were measured at 50 3 50 3 800 lm at 7 Tesla. Profiles of T1, T2, T2* and ADC
Relating the Newman-Penrose constants to the Geroch-Hansen multipole moments
Thomas Bäckdahl
2009-08-25T23:59:59.000Z
In this paper, we express the Newman--Penrose constants in terms of the Geroch--Hansen multipole moments for stationary spacetimes. These expressions are translation-invariant combinations of the multipole moments up to quadrupole order, which do not normally vanish.
V. P. Neznamov
2015-02-02T23:59:59.000Z
The paper presents the representation of quantum field theory without introduction of infinity bare masses and coupling constants of fermions. Counter-terms, compensating for divergent quantities in self-energy diagrams of fermions and vacuum polarization diagrams at all orders of the perturbation theory, appear in the appropriate Hamiltonians under the special time-dependent unitary transformation.
CODATA recommended values of the fundamental physical constants: Peter J. Mohr,
and may also be found on the World Wide Web at physics.nist.gov/constants. DOI: 10.1103/RevModPhys.80 B. M. Wood, National Research Council, Canada Z. Zhang, National Institute of Metrology, China and Chemical Reference Data. mohr@nist.gov barry.taylor@nist.gov § dnewell@nist.gov REVIEWS OF MODERN PHYSICS
680 Jones, Felderhof, Deutch Macromolecules If polymer chains are ruptured to a constant hydrody-
Deutch, John
of the Society of Polymer Science in Japan, October, 1974. References and Notes Y . Minonra, T. Kasuya, S680 Jones, Felderhof, Deutch Macromolecules If polymer chains are ruptured to a constant hydrody polymer bonds. Ac- cording to Harrington and Zimm,12polymers are considera- bly extended under a large
Photon emission in a constant magnetic field in 2+1 dimensional space-time
J. T. S. Amaral; S. I. Zlatev
2005-11-01T23:59:59.000Z
We calculate by the proper-time method the amplitude of the two-photon emission by a charged fermion in a constant magnetic field in (2+1)-dimensional space-time. The relevant dynamics reduces to that of a supesymmetric quantum-mechanical system with one bosonic and one fermionic degrees of freedom.
FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO
Le Roy, Robert J.
FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO Edward G. Lee-resolution FTIR emission spectroscopy measurements for the five common isoto- pomers of GeO are combined9), photoelectron spectroscopy (10), electronic absorption (1113), and emission (14) spectroscopy, and in matrix
Can Cosmological Constant be a Forbidden Zone (GAP) in Quantum Vacuum
Vladan Pankovic; Rade Glavatovic; Simo Ciganovic
2008-04-15T23:59:59.000Z
In this work we suggest, without detailed mathematical analysis, a hypothesis on the physical meaning of cosmological constant. It is primarily based on a conceptual analogy with energy characteristics of the crystal lattice structure, i.e. energy zones theory in solid state physics. Namely, according to some theories (holographic principle, emergent gravity etc.) it is supposed that empty space, i.e. quantum vacuum holds a structure like to crystal lattice. It implies a possibility of the existence of totally occupied zones consisting of many levels of the negative energies as well as at least one negative energy forbidden zone, i.e. negative energy gap without any (occupied or empty) level of the negative energy. We suppose that given negative energy forbidden zone in the quantum vacuum represents effectively a positive energy zone without quantum particles that corresponds to cosmological constant. Also we suggest some other (less extravagant) model of the cosmological constant. Here cosmological constant is usually considered as the effect of the quantum vacuum fluctuations where problem of the cut-off can be solved quite simply since here integration over unlimited domain of the quasi-momentums must be changed by integration over one, finite "Brillouin zone".
Sub-THz complex dielectric constants of smectite clay thin samples with Na$^{+}$/Ca$^{++}$-ions
Rezwanur Rahman; Douglas K. McCarty; Manika Prasad
2015-07-28T23:59:59.000Z
We implement a technique to characterize the electromagnetic properties at frequencies 100 to 165 GHz (3 cm$^{-1}$ to 4.95 cm$^{-1}$) of oriented smectite samples using an open cavity resonator connected to a sub-millimeter wave VNA (Vector Network Analyzer). We measured dielectric constants perpendicular to the bedding plane on oriented Na$^{+}$ and Ca$^{++}$-ion stabilized smectite samples deposited on a glass slide at ambient laboratory conditions (room temperature and room light). The clay layer is much thinner ($\\sim$ 30 $\\mu$m) than the glass substrate ($\\sim$ 2.18 mm). The real part of dielectric constant, $\\epsilon_{re}$, is essentially constant over this frequency range but is larger in Na$^{+}$- than in Ca$^{++}$-ion infused clay. The total electrical conductivity (associated with the imaginary part of dielectric constant, $\\epsilon_{im}$) of both samples increases monotonically at lower frequencies ($$ 110 GHz. The dispersion of the samples display a dependence on the ionic strength in the clay interlayers, i.e., $\\zeta$-potential in the Stern layers.
ur solid Earth undergoes constant change from motions within its core
McLeod, Dennis
O ur solid Earth undergoes constant change from motions within its core to the surface. Solid Earth is the physical planet we live on, not the oceans or atmosphere. Motions near Earth's cen- ter affect the geodynamo, which generates the Earth's magnetic field. Convection within Earth's mantle drives plate
Optimum Control for Interior Permanent Magnet Synchronous Motors (IPMSM) in Constant
Noé, Reinhold
Optimum Control for Interior Permanent Magnet Synchronous Motors (IPMSM) in Constant Torque and Electrical Drives, Paderborn, Germany Abstract--Interior Permanent Magnet Synchronous Motors (IPMSM) gain-power speed area. A widespread electrical machine used for this purpose is the Interior Permanent Magnet
Mechanics Systems on Para-Kaehlerian Manifolds of Constant J-Sectional Curvature
Mehmet Tekkoyun
2009-02-20T23:59:59.000Z
The goal of this paper is to present Euler-Lagrange and Hamiltonian equations on R2n which is a model of para-Kaehlerian manifolds of constant J-sectional curvature. In conclusion, some differential geometrical and physical results on the related mechanic systems have been given.
Dark energy, QCD axion, BICEP2, and trans-Planckian decay constant
Jihn E. Kim
2014-10-19T23:59:59.000Z
Discrete symmetries allowed in string compactification are the mother of all global symmetries which are broken at some level. We discuss the resulting pseudo-Goldstone bosons, in particular the QCD axion and a temporary cosmological constant, and inflatons. We also comment on some implications of the recent BICEP2 data.
The structure of reflexive regular splicing languages via Schutzenberger constants \\Lambda
Bonizzoni, Paola
by Paun and Pixton respectively [16, 20]. The computational power of splicing systems has been thoroughlyThe structure of reflexive regular splicing languages via Sch¨utzenberger constants \\Lambda Paola generating) device, called a splicing system. Other variants of this original definition were also proposed
Constraints on the value of the fine structure constant from gravitational thermodynamics
P. C. W. Davies
2007-09-26T23:59:59.000Z
In this paper I show how the second law of thermodynamics, generalized to include event horizon area, places interesting constraints on the value of the fine structure constant. A simple analysis leads to the conclusion that classical Dirac and point-like magnetic monopoles could be used to violate the second law, and that GUT monopoles are inconsistent with minicharged particles.
On the variation of the fine-structure constant in Friedmann Universes
William Q. Sumner
2005-03-07T23:59:59.000Z
The fine-structure constant alpha does not vary as Friedmann Universes evolve, a conclusion based on assessments of quantum mechanics and electrodynamics. alpha = e^2/(4pi epsilon hbar c), where e is the charge of the electron, epsilon is vacuum permittivity, c is the speed of light, and hbar is Planck's constant divided by 2pi. This inquiry was motivated by Schrodinger's (1939) prediction that all quantum wave functions coevolve with Friedmann geometry and a similar prediction by Sumner (1994) for vacuum permittivity. The functional form of variations in quantum wave functions found by Schrodinger is enough to show that alpha does not vary. Electrodynamics also predicts that alpha does not vary. Evolutionary changes in c exactly cancel those in vacuum permittivity and other factors in alpha do not change. Since alpha appears in all first-order perturbation formulas for atomic energy levels, comparisons of the atomic spectra of distant atoms with those in laboratories provide an experimental measure of this prediction. Most experiments find changes in alpha that are either statistically zero or very small. These results and estimates of the Hubble constant and deceleration parameter from precision redshift/magnitude data support a major assumption of this paper that the Friedmann solution to Einstein's theory of general relativity without cosmological constant is an adequate approximation to spacetime geometry and its long term evolution at quantum scales.
Evolving Lorentzian wormholes supported by phantom matter with constant state parameters
Mauricio Cataldo; Pedro Labrana; Sergio del Campo; Juan Crisostomo; Patricio Salgado
2008-10-15T23:59:59.000Z
In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made out of phantom energy. We show that this exotic source can support the existence of evolving wormhole spacetimes. Explicitly, a family of evolving Lorentzian wormholes conformally related to another family of zero-tidal force static wormhole geometries is found in Einstein gravity. Contrary to the standard wormhole approach, where first a convenient geometry is fixed and then the matter distribution is derived, we follow the conventional approach for finding solutions in theoretical cosmology. We derive an analytical evolving wormhole geometry by supposing that the radial tension (which is negative to the radial pressure) and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. At spatial infinity this evolving wormhole, supported by this anisotropic matter, is asymptotically flat, and its slices $t=$ constant are spaces of constant curvature. During its evolution the shape of the wormhole expands with constant velocity, i.e without acceleration or deceleration, since the scale factor has strictly a linear evolution.
The Price of Anarchy in Network Creation Games Is (Mostly) Constant
Fiat, Amos
The Price of Anarchy in Network Creation Games Is (Mostly) Constant Mat´us Mihal´ak and Jan the price of anarchy and the structure of equilibria in network creation games. A network creation game in the resulting graph of the game. In this paper we improve previously known bounds on the price of anarchy
Optical constants of ice from the ultraviolet to the microwave: A revised compilation
Warren, Stephen
only in the far infrared. Tables of the revised optical constants are available on a website. Citation not be significant. (The revised compilation is available as tables at http and Price [2001] reviewed experimental results from several publica- tions and concluded that the absorption
On the asymptotic homotopy type of inductive limit
Let X, Y be compact, connected, metrisable spaces with base points Xo, Yo and ... algebras whose asymptotic homotopy type is determined by K-theoretical data.
The rate constant for radiative association of HF: Comparing quantum and classical dynamics
Gustafsson, Magnus, E-mail: magngu@chem.gu.se; Monge-Palacios, M.; Nyman, Gunnar [Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg (Sweden)] [Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg (Sweden)
2014-05-14T23:59:59.000Z
Radiative association for the formation of hydrogen fluoride through the A{sup 1}? ? X{sup 1}?{sup +} and X{sup 1}?{sup +} ? X{sup 1}?{sup +} transitions is studied using quantum and classical dynamics. The total thermal rate constant is obtained for temperatures from 10 K to 20 000 K. Agreement between semiclassical and quantum approaches is observed for the A{sup 1}? ? X{sup 1}?{sup +} rate constant above 2000 K. The agreement is explained by the fact that the corresponding cross section is free of resonances for this system. At temperatures below 2000 K we improve the agreement by implementing a simplified semiclassical expression for the rate constant, which includes a quantum corrected pair distribution. The rate coefficient for the X{sup 1}?{sup +} ? X{sup 1}?{sup +} transition is calculated using Breit–Wigner theory and a classical formula for the resonance and direct contributions, respectively. In comparison with quantum calculations the classical formula appears to overestimate the direct contribution to the rate constant by about 12% for this transition. Below about 450 K the resonance contribution is larger than the direct, and above that temperature the opposite holds. The biggest contribution from resonances is at the lowest temperature in the study, 10 K, where it is more than four times larger than the direct. Below 1800 K the radiative association rate constant due to X{sup 1}?{sup +} ? X{sup 1}?{sup +} transitions dominates over A{sup 1}? ? X{sup 1}?{sup +}, while above that temperature the situation is the opposite.
Jeremy R Mould; John P Huchra; Wendy L Freedman; Robert C Kennicutt Jr; Laura Ferrarese; Holland C Ford; Brad K Gibson; John A Graham; Shaun Hughes; Garth D Illingworth; Daniel D Kelson; Lucas M Macri; Barry F Madore; Shoko Sakai; Kim Sebo; Nancy A Silbermann; Peter B Stetson
1999-09-15T23:59:59.000Z
Since the launch of the Hubble Space Telescope nine years ago, Cepheid distances to 25 galaxies have been determined for the purpose of calibrating secondary distance indicators. A variety of these can now be calibrated, and the accompanying papers by Sakai, Kelson, Ferrarese, and Gibson employ the full set of 25 galaxies to consider the Tully-Fisher relation, the fundamental plane of elliptical galaxies, Type Ia supernovae, and surface brightness fluctuations. When calibrated with Cepheid distances, each of these methods yields a measurement of the Hubble constant and a corresponding measurement uncertainty. We combine these measurements in this paper, together with a model of the velocity field, to yield the best available estimate of the value of H_0 within the range of these secondary distance indicators and its uncertainty. The result is H_0 = 71 +/- 6 km/sec/Mpc. The largest contributor to the uncertainty of this 67% confidence level result is the distance of the Large Magellanic Cloud, which has been assumed to be 50 +/- 3 kpc.
C. J. A. P. Martins; A. M. M. Pinho; R. F. C. Alves; M. Pino; C. I. S. A. Rocha; M. von Wietersheim
2015-08-25T23:59:59.000Z
Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant $\\alpha$, are becoming an increasingly powerful probe of new physics. Here we discuss how these measurements, combined with local atomic clock tests and Type Ia supernova and Hubble parameter data, constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling, $\\zeta$, to the electromagnetic sector) the $\\alpha$ variation. Specifically, current data tightly constrains a combination of $\\zeta$ and the present dark energy equation of state $w_0$. Moreover, in these models the new degree of freedom inevitably couples to nucleons (through the $\\alpha$ dependence of their masses) and leads to violations of the Weak Equivalence Principle. We obtain indirect bounds on the E\\"otv\\"os parameter $\\eta$ that are typically stronger than the current direct ones. We discuss the model-dependence of our results and briefly comment on how the forthcoming generation of high-resolution ultra-stable spectrographs will enable significantly tighter constraints.
H. W. Peng
2004-01-27T23:59:59.000Z
Taking a hint from Dirac's large number hypothesis, we note the existence of cosmic combined conservation laws that work to cosmologically long time. We thus modify or generalize Einstein's theory of general relativity with fixed gravitation constant $G$ to a theory for varying $G$, which can be applied to cosmology without inconsistency, where a tensor arising from the variation of G takes the place of the cosmological constant term. We then develop on this basis a systematic theory of evolving natural constants $m_{e},m_{p},e,\\hslash ,k_{B}$ by finding out their cosmic combined counterparts involving factors of appropriate powers of $G$ that remain truly constant to cosmologically long time. As $G$ varies so little in recent centuries, so we take these natural constants to be constant.
Sivaramakrishnan, R.; Michael, J.V. [Chemical Sciences and Engineering Division, D-193, Bldg. 200, Argonne National Laboratory, Argonne, IL 60439 (United States)
2009-05-15T23:59:59.000Z
High temperature experiments were performed with the reflected shock tube technique using multi-pass absorption spectrometric detection of OH radicals at 308 nm. The present experiments span a wide T-range, 801-1347 K, and represent the first direct measurements of the title rate constants at T>500 K for cyclopentane and cyclohexane and the only high temperature measurements for the corresponding methyl derivatives. The present work utilized 48 optical passes corresponding to a total path length {proportional_to}4.2 m. As a result of this increased path length, the high [OH] detection sensitivity permitted unambiguous analyses for measuring the title rate constants. The experimental rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, can be expressed in Arrhenius form as k{sub OH+Cyclopentane}=(1.90{+-}0.30) x 10{sup -10}exp(-1705{+-}56 K/T) (813-1341 K), k{sub OH+Cyclohexane}=(1.86{+-}0.24) x 10{sup -10}exp(-1513{+-}123 K/T) (801-1347 K), k{sub OH+Methylcyclopentane}=(2.02{+-}0.19) x 10{sup -10}exp(-1799{+-}96 K/T) (859-1344 K), k{sub OH+Methylcyclohexane}=(2.55{+-}0.30) x 10{sup -10}exp(-1824{+-}114 K/T) (836-1273 K). These results and lower-T experimental data were used to obtain three parameter evaluations of the experimental rate constants for the title reactions over an even wider T-range. These experimental three parameter fits to the rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, are k{sub OH+Cyclopentane}=1.390 x 10{sup -16}T{sup 1.779}exp(97 K/T)cm{sup 3} molecule{sup -1}s{sup -1} (209-1341 K), k{sub OH+Cyclohexane}=3.169 x 10{sup -16}T{sup 1.679}exp(119 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (225-1347 K), k{sub OH+Methylcyclopentane}=6.903 x 10{sup -18}T{sup 2.148}exp(536 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (296-1344 K), k{sub OH+Methylcyclohexane}=2.341 x 10{sup -18}T{sup 2.325}exp(602 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (296-1273 K). High level electronic structure methods were used to characterize the first three reactions in order to provide reliable extrapolations of the rate constants from 250-2000 K. The results of the theoretical predictions for OH + cyclohexane and OH + methylcyclopentane were sufficient to make a theoretical prediction for OH + methylcyclohexane. The present recommended rate expressions for OH with cyclohexane, and methylcyclohexane, give rate constants that are 15-25% higher (over the T-range 800-1300 K) than the rate constants utilized in recent modeling efforts aimed at addressing the oxidation of cyclohexane and methylcyclohexane. The current measurements reduce the uncertainties in rate constants for the primary cycloalkane consumption channel in a high temperature oxidation environment. (author)
Sivaramakrishnan, R.; Michael, J. V.; Chemical Sciences and Engineering Division
2009-05-01T23:59:59.000Z
High temperature experiments were performed with the reflected shock tube technique using multi-pass absorption spectrometric detection of OH radicals at 308 nm. The present experiments span a wide T-range, 801-1347 K, and represent the first direct measurements of the title rate constants at T>500 K for cyclopentane and cyclohexane and the only high temperature measurements for the corresponding methyl derivatives. The present work utilized 48 optical passes corresponding to a total path length 4.2 m. As a result of this increased path length, the high [OH] detection sensitivity permitted unambiguous analyses for measuring the title rate constants. The experimental rate constants in units, cm3 molecule-1 s-1, can be expressed in Arrhenius form as k{sub OH+Cyclopentane} = (1.90 {+-} 0.30) x 10{sup -10} exp(-1705 {+-} 156 K/T) (813-1341 K), k{sub OH+Cyclohexane} = (1.86 {+-} 0.24) x 10{sup -10} exp(-1513 {+-} 123 K/T) (801-1347 K), k{sub OH+Methylcyclopentane} = (2.02 {+-} 0.19) x 10{sup -10} exp(-1799 {+-} 96 K/T) (859-1344 K), k{sub OH+Methylcyclohexane} = (2.55 {+-} 0.30) x 10{sup -10} exp(-1824 {+-} 114 K/T) (836-1273 K). These results and lower-T experimental data were used to obtain three parameter evaluations of the experimental rate constants for the title reactions over an even wider T-range. These experimental three parameter fits to the rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, are k{sub OH+Cyclopentane} = 1.390 x 10{sup -16}T{sup 1.779} exp(97 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (209-1341 K), k{sub OH+Cyclohexane} = 3.169 x 10{sup -16} T{sup 1.679} exp(119 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (225-1347 K), k{sub OH+Methylcyclopentane} = 6.903 x 10{sup -18}T{sup 2.148} exp(536 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (296-1344 K), k{sub OH+Methylcyclohexane} = 2.341 x 10{sup -18}T{sup 2.325} exp(602 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (296-1273 K). High level electronic structure methods were used to characterize the first three reactions in order to provide reliable extrapolations of the rate constants from 250-2000 K. The results of the theoretical predictions for OH + cyclohexane and OH + methylcyclopentane were sufficient to make a theoretical prediction for OH + methylcyclohexane. The present recommended rate expressions for OH with cyclohexane, and methylcyclohexane, give rate constants that are 15-25% higher (over the T-range 800-1300 K) than the rate constants utilized in recent modeling efforts aimed at addressing the oxidation of cyclohexane and methylcyclohexane. The current measurements reduce the uncertainties in rate constants for the primary cycloalkane consumption channel in a high temperature oxidation environment.
Type of Space Bulb Type #/House Fixture Style Greenhouse #
Pawlowski, Wojtek
Type of Space Bulb Type #/House Fixture Style Greenhouse # 1 Lu 430/Lu 400 24 White box style 2 Lu No bulbs 0 N/A Seed harvest room F32 T8/TL 841 90 bulbs VIGS Room F032 /741/ECO 60 bulbs Chamber Model Bulb
Portfolio Manager Space Type Discussion
Broader source: Energy.gov [DOE]
This presentation, given through the DOE's Technical Assitance Program (TAP), provides a discussion about space/type in regards to the Portfolio Manager Initiative.
Portfolio Manager Space Type Discussion
Broader source: Energy.gov [DOE]
This presentation, given through the DOE's Technical Assistance Program (TAP), provides a discussion about space/type in regards to the Portfolio Manager Initiative.
Maintenance Types | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
requirements of any physical asset within its operating context. Chapter 5 of the Federal Energy Management Program's O&M Best Practices Guide outlines these maintenance types in...
Archived Reference Building Type: Warehouse
Broader source: Energy.gov [DOE]
Here you will find past versions of the commercial reference building models for existing buildings constructed in or after 1980, organized by building type and location. A summary of building types and climate zones is available for reference. Current versions are also available.
Archived Reference Building Type: Warehouse
Broader source: Energy.gov [DOE]
Here you will find past versions of the commercial reference building models for existing buildings constructed before 1980, organized by building type and location. A summary ofbuilding types and climate zones is available for reference. Current versions are also available.
Light pseudoscalar meson masses and decay constants from mixed action lattice QCD
Christopher Aubin; Jack Laiho; Ruth S. Van de Water
2008-10-23T23:59:59.000Z
We calculate the light pseudoscalar decay constants, f_pi and f_K, and their ratio using domain wall valence quarks and 2+1 flavors of dynamical staggered quarks. Use of the MILC gauge configurations allows us to simulate at several sea quark masses and spatial volumes, and with two lattice spacings. We study how well our numerical lattice data for light decay constants and meson masses is described by next-to-leading order SU(3) mixed action chiral perturbation theory and explain our strategy for the chiral and continuum extrapolation. Combining our result for f_K/f_pi with experimental measurements of pion and kaon leptonic decays allows a model-independent determination of |V_us|/|V_ud|; we find a preliminary value of |V_us|/|V_ud| = 0.2315(45)(7).
Third- and fourth-order constants of incompressible soft solids and the acousto-elastic effect
Michel Destrade; Michael D. Gilchrist; G. Saccomandi
2013-01-29T23:59:59.000Z
Acousto-elasticity is concerned with the propagation of small-amplitude waves in deformed solids. Results previously established for the incremental elastodynamics of exact non-linear elasticity are useful for the determination of third- and fourth-order elastic constants, especially in the case of incompressible isotropic soft solids, where the expressions are particularly simple. Specifically, it is simply a matter of expanding the expression for $\\rho v^2$, where $\\rho$ is the mass density and v the wave speed, in terms of the elongation $e$ of a block subject to a uniaxial tension. The analysis shows that in the resulting expression: $\\rho v^2 = a + be + ce^2$, say, $a$ depends linearly on $\\mu$; $b$ on $\\mu$ and $A$; and $c$ on $\\mu$, $A$, and $D$, the respective second-, third, and fourth-order constants of incompressible elasticity, for bulk shear waves and for surface waves.
Low energy constants from the chirally improved Dirac operator D_CI
Christof Gattringer; Philipp Huber; C. B. Lang
2005-09-30T23:59:59.000Z
The leading order low energy parameters like the pion decay constant or the quark condensate are well-known from "classical" low energy theorems and experiments. It is a challenge, however, to find these parameters based exclusively on an ab-initio QCD calculation. We discuss results of a quenched lattice calculation of low energy constants using the chirally improved Dirac operator. Several lattice sizes at different lattice spacings are studied, using pseudoscalar and axial vector correlators. We find consistent results for f_\\pi = 96(2) MeV, f_K = 105(2) MeV, \\Sigma = -(286(4) MeV)^3, the average light quark mass m = 4.1(2.4) MeV and m_s = 101(8) MeV.
Heavy-light decay constants---MILC results with the Wilson action
MILC Collaboration; Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; Jim Hetrick; Craig McNeile; Kari Rummukainen; A. Soni; Bob Sugar; Doug Toussaint; Matthew Wingate
1997-07-15T23:59:59.000Z
We present the current status of our ongoing calculations of pseudoscalar meson decay constants for mesons that contain one light and one heavy quark (f_B, f_{B_s}, f_D, f_{D_s}). We are currently generating new gauge configurations that include dynamical quarks and calculating the decay constants. In addition, we have several new results for the static approximation. Those results, as well as several refinements to the analysis, are new since Lattice '96. Our current (still preliminary) value for f_B is 156 +- 11 +- 30 +- 14 MeV, where the first error is from statistical and fitting errors, the second error is an estimate of other systematic errors within the quenched approximation and the third error is an estimate of the quenching error. For the ratio f_{B_s}/f_B, we get 1.11 +- 0.02 +- 0.03 +- 0.07.
Measurement of the pure dissolution rate constant of a mineral in water
Colombani, Jean
2009-01-01T23:59:59.000Z
We present here a methodology, using holographic interferometry, enabling to measure the pure surface reaction rate constant of the dissolution of a mineral in water, unambiguously free from the influence of mass transport. We use that technique to access to this value for gypsum and we demonstrate that it was never measured before but could be deduced a posteriori from the literature results if hydrodynamics is taken into account with accuracy. It is found to be much smaller than expected. This method enables to provide reliable rate constants for the test of dissolution models and the interpretation of in situ measurements, and gives clues to explain the inconsistency between dissolution rates of calcite and aragonite, for instance, in the literature.
A Novel Active Bouncer System for Klystron Modulators with Constant AC Power Consumption
Cabaleiro Magallanes, F; Viarouge, P; Cros, J; De Almeida Martins, C
2014-01-01T23:59:59.000Z
This paper presents the principles and design methodologies of a novel active bouncer system, to be implemented in a transformer-based klystron modulator, which is able to meet two different objectives: 1. Regulate the output pulse voltage flattop, and 2. Attenuate the power fluctuation withdrawn from the AC network. This solution allows the utilization of a standard constant voltage / constant current power supply as a capacitor charger. The solution consists of a 4-quadrant switching converter placed in series with the main capacitor bank (forming a unique element in parallel with the capacitor charger), controlled with specific feed-back loops to achieve the two objectives. The complete design method, including a numerical optimization, of the whole system, is presented in the paper. Analyses of the compromises between the active bouncer specifications and the other modulator sub-components design is presented as well.
HQET at order 1/m: III. Decay constants in the quenched approximation
Benoît Blossier; Michele Della Morte; Nicolas Garron; Georg von Hippel; Tereza Mendes; Hubert Simma; Rainer Sommer
2010-10-25T23:59:59.000Z
We report on the computation of the $B_s$ meson decay constant in Heavy Quark Effective Theory on the lattice. The next to leading order corrections in the HQET expansion are included non-perturbatively. We estimate higher order contributions to be very small. The results are extrapolated to the continuum limit, the main systematic error affecting the computation is therefore the quenched approximation used here. The Generalized Eigenvalue Problem and the use of all-to-all propagators are important technical ingredients of our approach that allow to keep statistical and systematic errors under control. We also report on the decay constant $f_{B'_s}$ of the first radially excited state in the $B_s$ sector, computed in the static limit.
The Einstein-Hilbert action with cosmological constant as a functional of generic form
Tolksdorf Juergen
2014-07-14T23:59:59.000Z
The geometrical underpinnings of a specific class of Dirac operators is discussed. It is demonstrated how this class of Dirac operators allow to relate various geometrical functionals like, for example, the Yang-Mills action and the functional of non-linear $\\sigma-$models (i.e. of (Dirac) harmonic maps). These functionals are shown to be similar to the Einstein-Hilbert action with cosmological constant (EHC). The EHC may thus be regarded as a "generic functional". As a byproduct, the geometrical setup presented also allows to avoid the issue of "fermion doubling" as usually encountered, for instance, in the geometrical discussion of the Standard Model in terms of Dirac operators. Furthermore, it is demonstrated how the geometrical setup presented allows to derive the cosmological constant term of the EHC from the Einstein-Hilbert functional and the action of a purely gauge coupling Higgs field.
Darquié, Benoît; Sow, Papa Lat Tabara; Lemarchand, Cyril; Triki, Meriam; Tokunaga, Sean; Bordé, Christian J; Chardonnet, Christian; Daussy, Christophe
2015-01-01T23:59:59.000Z
Accurate molecular spectroscopy in the mid-infrared region allows precision measurements of fundamental constants. For instance, measuring the linewidth of an isolated Doppler-broadened absorption line of ammonia around 10 $\\mu$m enables a determination of the Boltzmann constant k B. We report on our latest measurements. By fitting this lineshape to several models which include Dicke narrowing or speed-dependent collisional effects, we find that a determination of k B with an uncertainty of a few ppm is reachable. This is comparable to the best current uncertainty obtained using acoustic methods and would make a significant contribution to any new value of k B determined by the CODATA. Furthermore, having multiple independent measurements at these accuracies opens the possibility of defining the kelvin by fixing k B, an exciting prospect considering the upcoming redefinition of the International System of Units.
Constants of the Motion in a Gravitational Field and the Hamilton-Jacobi Function
Paul O'Hara
2012-08-25T23:59:59.000Z
In most text books of mechanics, Newton's laws or Hamilton's equations of motion are first written down and then solved based on initial conditions to determine the constants of the motions and to describe the trajectories of the particles. In this essay, we take a different starting point. We begin with the metrics of general relativity and show how they can be used to construct by inspection constants of motion, which can then be used to write down the equations of the trajectories. This will be achieved by deriving a Hamiltonian-Jacobi function from the metric and showing that its existence requires all of the above mentioned properties. The article concludes with four applications, which includes a derivation of Kepler's First Law of Motion for planets, and a formula for describing the trajectories of galaxies moving in a space defined by the Robertson-Walker metric.
Production of natural gas from methane hydrate by a constant downhole pressure well
Ahmadi, G. (Clarkson Univ., Potsdam, NY); Ji, C. (Clarkson Univ., Potsdam, NY); Smith, D.H.
2007-07-01T23:59:59.000Z
Natural gas production from the dissociation of methane hydrate in a confined reservoir by a depressurizing downhole well was studied. The case that the well pressure was kept constant was treated, and two different linearization schemes in an axisymmetric configuration were used in the analysis. For different fixed well pressures and reservoir temperatures, approximate self similar solutions were obtained. Distributions of temperature, pressure and gas velocity field across the reservoir were evaluated. The distance of the decomposition front from the well and the natural gas production rate as functions of time were also computed. Time evolutions of the resulting profiles were presented in graphical forms, and their differences with the constant well output results were studied. It was shown that the gas production rate was a sensitive function of well pressure and reservoir temperature. The sensitivity of the results to the linearization scheme used was also studied.
Decay b{yields}s{gamma} in the presence of a constant antisymmetric tensor field
Ahuatzin, G. [Instituto de Fisica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, Zona Centro, San Luis Potosi, S.L.P. 78000 (Mexico); Bautista, I. [IGFAE and Departamento de Fisica de Particulas, Univ. of Santiago de Compostela, 15706, Santiago de Compostela (Spain); Hernandez-Lopez, J. A.; Toscano, J. J. [Facultad de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla, Apartado Postal 1152, Puebla, Puebla (Mexico); Ramirez-Zavaleta, F. [Facultad de Ciencias Fisico Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Avenida Francisco J. Mujica S/N, 58060, Morelia, Michoacan (Mexico)
2010-09-01T23:59:59.000Z
A constant antisymmetric 2-tensor can arise in general relativity with spontaneous symmetry breaking or in field theories formulated in a noncommutative space-time. In this work, the one-loop contribution of a nonstandard WW{gamma} vertex on the flavor violating quark transition q{sub i}{yields}q{sub j}{gamma} is studied in the context of the electroweak Yang-Mills sector extended with a Lorentz-violating constant 2-tensor. An exact analytical expression for the on-shell case is presented. It is found that the loop amplitude is gauge independent, electromagnetic gauge invariant, and free of ultraviolet divergences. The dipolar contribution to the b{yields}s{gamma} transition together with the experimental data on the B{yields}X{sub s{gamma}} decay is used to derive the constraint {Lambda}{sub LV}>1.96 TeV on the Lorentz-violating scale.
Taylor, DeCarlos E., E-mail: decarlos.e.taylor.civ@mail.mil [U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)
2014-08-07T23:59:59.000Z
The elastic constants of the ? and ? polymorphs of cyclotrimethylene trinitramine (RDX) have been computed using dispersion corrected density functional theory (DFT). The DFT results validate the values obtained in several experiments using ultrasonic and impulsive stimulated thermal scattering techniques and disagree with those obtained using Brillouin scattering which, in general, exceed the other experimental and theoretical results. Compressibility diagrams at zero pressure are presented for the ab, ac, and bc crystallographic planes, and the anisotropic linear compressibility within the ac plane of ?-RDX at 0?GPa, observed using ultrasonic and impulsive stimulated thermal scattering measurements, is verified using DFT. The pressure dependence of the elastic constants of ?-RDX (0–4?GPa) and ?-RDX (4–8?GPa) is also presented.
Measurement of the pure dissolution rate constant of a mineral in water
Jean Colombani
2009-11-26T23:59:59.000Z
We present here a methodology, using holographic interferometry, enabling to measure the pure surface reaction rate constant of the dissolution of a mineral in water, unambiguously free from the influence of mass transport. We use that technique to access to this value for gypsum and we demonstrate that it was never measured before but could be deduced a posteriori from the literature results if hydrodynamics is taken into account with accuracy. It is found to be much smaller than expected. This method enables to provide reliable rate constants for the test of dissolution models and the interpretation of in situ measurements, and gives clues to explain the inconsistency between dissolution rates of calcite and aragonite, for instance, in the literature.
The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature
Lamoreaux, Steve (LANL) [LANL
2005-11-07T23:59:59.000Z
Natural nuclear reactors? Changes in the speed of light? If either of these concepts seem implausible to you now they certainly won't once Dr. Steve Lamoreaux (LANL) delivers his SLAC Colloquium lecture in the Panofsky Auditorium on November 7th at 4:15 pm entitled The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature. This lecture is a rare opportunity to learn not only about Oklo's incredible natural nuclear reactors but also to gain understanding about how the present-day study of these sites may alter our understanding of fundamental constants such as the speed of light. This event is a must-see for the curious!
p=constant compression on loose Hostun sand: The case of an anisotropic response
P. Evesque
2005-07-08T23:59:59.000Z
Experimental data from axially symmetric compression test at constant mean pressure p on Hostun sand from Flavigny experiments on loose sands are used to study the validity of an "isotropic" modelling at different densities . It is found that the material response is not isotropic even at small deviatoric stress. As an "isotropic" behaviour is found for compression test at constant volume on the same sand, this new result questions the unicity of the trajectory in the classical phase space of soil mechanics (q,p,v), with q being thed deviatoric stress, v the specific volume. This asks whether the space shall be taken larger than 3d or not. Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn
Exact solution to the Landau-Lifshitz equation in a constant electromagnetic field
Yurij Yaremko
2014-12-04T23:59:59.000Z
We are interested in the motion of a classical charge acted upon an external constant electromagnetic field where the back reaction of the particle's own field is taken into account. The Landau-Lifshitz approximation to the Lorentz-Abraham-Dirac equation is solved exactly and in closed form. It is shown that the ultrarelativistic limit of the Landau-Lifshitz equation for a radiating charge is the equation for eigenvalues and eigenvectors of the external electromagnetic field tensor.
Quantization of a particle on a two-dimensional manifold of constant curvature
Bracken, Paul [Department of Mathematics, University of Texas, Edinburg, Texas 78540 (United States)
2014-10-15T23:59:59.000Z
The formulation of quantum mechanics on spaces of constant curvature is studied. It is shown how a transition from a classical system to the quantum case can be accomplished by the quantization of the Noether momenta. These can be determined by means of Lie differentiation of the metric which defines the manifold. For the metric examined here, it is found that the resulting Schrödinger equation is separable and the spectrum and eigenfunctions can be investigated in detail.
The theory of Multiverse, multiplicity of physical objects and physical constants
Alexander K. Gouts
2002-10-22T23:59:59.000Z
The Multiverse is collection of parallel universes. In this article a formal theory and a topos-theoretic models of the multiverse are given. For this the Lawvere-Kock Synthetic Differential Geometry and topos models for smooth infinitesimal analysis are used. Physical properties of multi-variant and many-dimensional parallel universes are discussed. The source of multiplicity of physical objects is set of physical constants.
Tsunami and acoustic-gravity waves in water of constant depth
Hendin, Gali; Stiassnie, Michael [Faculty of Civil and Environmental Engineering, Technion – Israel institute of technology, Haifa 32000 (Israel)] [Faculty of Civil and Environmental Engineering, Technion – Israel institute of technology, Haifa 32000 (Israel)
2013-08-15T23:59:59.000Z
A study of wave radiation by a rather general bottom displacement, in a compressible ocean of otherwise constant depth, is carried out within the framework of a three-dimensional linear theory. Simple analytic expressions for the flow field, at large distance from the disturbance, are derived. Realistic numerical examples indicate that the Acoustic-Gravity waves, which significantly precede the Tsunami, are expected to leave a measurable signature on bottom-pressure records that should be considered for early detection of Tsunami.
Masses, decay constants and electromagnetic form-factors with twisted boundary conditions
Bijnens, Johan
2015-01-01T23:59:59.000Z
We discuss some of the effects of twisted boundary conditions in finite volume using continuum SU(3) Chiral Perturbation Theory. We point out how broken cubic symmetry affects the definitions of quantities such as form-factors. Using the $\\pi^+$ as an example, we give one loop results for the mass, decay constants and electromagnetic form-factor and illustrate how the relevant Ward identities are satisfied.
Masses, decay constants and electromagnetic form-factors with twisted boundary conditions
Johan Bijnens; Johan Relefors
2015-09-24T23:59:59.000Z
We discuss some of the effects of twisted boundary conditions in finite volume using continuum SU(3) Chiral Perturbation Theory. We point out how broken cubic symmetry affects the definitions of quantities such as form-factors. Using the $\\pi^+$ as an example, we give one loop results for the mass, decay constants and electromagnetic form-factor and illustrate how the relevant Ward identities are satisfied.
Energy Loss of Heavy Quarks in a QGP with a Running Coupling Constant Approach
Pol B. Gossiaux; Joerg Aichelin
2009-09-23T23:59:59.000Z
We show that the effective running coupling constant, $\\alpha_{\\rm eff}$, and the effective regulator, $\\kappa \\tilde{m}_{D}^2$, which we used recently to calculate the energy loss, $\\frac{dE}{dx}$, and the elliptic flow, $v_2$, of heavy quarks in an expanding quark gluon plasma plasma (QGP) are compatible with lattice results and with recently advanced analytical pQCD calculation.
Variation of calibration constant of alpha track detectors with respect to altitude
Vasudevan, Latha
1991-01-01T23:59:59.000Z
solutions, has been found useful in determining the degree of etch. The study reported here is not only limited to finding out the calibration constant of LR 115 II films at ambient atmospheric pressure, but also under various air pressure conditions... Chamber Detector System Lucas Cell Efficiency Calibration of the Lucas Cell Etching Bath Etching Vial Image Processing System Calibration of the Optical System 24 24 25 26 27 30 34 35 36 36 Particle Track Counting Spectrophotometry...
Computation of the O(p^6) order low-energy constants: an update
Shao-Zhou Jiang; Zhen-Long Wei; Qing-Sen Chen; Qing Wang
2015-02-17T23:59:59.000Z
We update our original low-energy constants to the O(p6) order, including two and three flavours, the normal and anomalous ones. Following a comparative analysis, the O(p4) results are considered better. In the O(p6) order, most of our results are consistent or better with those we have found in the literature, although several are worse.
Future stability of the FLRW fluid solutions in the presence of a positive cosmological constant
Todd A. Oliynyk
2015-05-05T23:59:59.000Z
We introduce a new method for establishing the future non-linear stability of perturbations of FLRW solutions to the Einstein-Euler equations with a positive cosmological constant and a linear equation of state of the form $\\rho = K p$. The method is based on a conformal transformation of the Einstein-Euler equations that compactifies the time domain and can handle the equation of state parameter values $0future.
Strong coupling constants of heavy baryons with light mesons in QCD
Aliev, T. M.; Azizi, K.; Savci, M. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey); Physics Department, Faculty of Arts and Sciences, Dogus University, Ac Latin-Small-Letter-Dotless-I badem-Kad Latin-Small-Letter-Dotless-I koey, 34722 Istanbul (Turkey); Physics Department, Middle East Technical University, 06531 Ankara (Turkey)
2012-10-23T23:59:59.000Z
The strong coupling constants of the heavy spin-1/2 and spin-3/2 baryons with light pseudoscalar and vector mesons are calculated in the framework of the light cone QCD sum rules. Using the symmetry arguments, some structure independent relations among different correlation functions are obtained. It is shown that all possible transitions are described by only one invariant function, whose explicit expression is structure dependent.
The theory of Multiverse, multiplicity of physical objects and physical constants
Gouts, A K
2003-01-01T23:59:59.000Z
The Multiverse is collection of parallel universes. In this article a formal theory and a topos-theoretic models of the multiverse are given. For this the Lawvere-Kock Synthetic Differential Geometry and topos models for smooth infinitesimal analysis are used. Physical properties of multi-variant and many-dimensional parallel universes are discussed. The source of multiplicity of physical objects is set of physical constants.
PROPERTY TABLES AND CHARTS (SI UNITS) Table A1 Molar mass, gas constant, and
Kostic, Milivoje M.
Table A20 Ideal-gas properties of carbon dioxide, CO2 Table A21 Ideal-gas properties of carbon.1355 n-Butane C4H10 58.124 0.1430 425.2 3.80 0.2547 Carbon dioxide CO2 44.01 0.1889 304.2 7.39 0Appendix 1 PROPERTY TABLES AND CHARTS (SI UNITS) Table A1 Molar mass, gas constant, and critical
A definition of the running coupling constant in a twisted SU(2) lattice gauge theory
G. M. de Divitiis; R. Frezzotti; M. Guagnelli; R. Petronzio
1993-12-28T23:59:59.000Z
We propose a definition of the running coupling constant in a SU(2) lattice gauge theory with twisted boundary conditions. It is based on the correlation of Polyakov loops extended in a twisted direction at a distance which is a fixed fraction of the totale lattice size. We make the perturbative calculation which connects this definition to standard regularization schemes. We find Lambda_Twisted-Polyakov/Lambda_MSbar = 1.6136(2).
Recent advances in the measurement of high temperature bimolecular rate constants
Michael, J.V.
1995-07-01T23:59:59.000Z
Recent advances in the measurement of high temperature reaction rate constants are discussed. The studies carried out by shock tube methods are particularly considered because these results are important not only in theoretical chemical kinetics but also in practical applications. The work on 5 chemical reactions are reviewed in detail. These are: D + H{sub 2}, Cl + H{sub 2}, H + O{sub 2}, CH{sub 3} + CH{sub 3}, and H + NO{sub 2}.
A Time Varying Strong Coupling Constant as a Model of Inflationary Universe
N. Chamoun; S. J. Landau; H. Vucetich
2004-09-17T23:59:59.000Z
We consider a scenario where the strong coupling constant was changing in the early universe. We attribute this change to a variation in the colour charge within a Bekenstein-like model. Treating the vacuum gluon condensate $$ as a free paramete r, we could generate inflation with the required properties to solve the fluctuation and other standard cosmology problems. A possible approach to end the inflation is suggested.
Liu, M.; Athar, A.; Reddy, A.; Claridge, D. E.; Haberl, J. S.; White, E.
1994-01-01T23:59:59.000Z
Study on Energy Eficiency in Buildings. Vol. 3, pp. 3.12 1-3.129. 4. Tamblyn. B. 1992. "Commissioning: An Operation and Maintenance Perspective". ASHRAE Journal. Vol. 7, NO. 10, pp. 22-26. - 5. Szydlowski. R. et al. 1992. "Measured Energy Savings...REDUCING BUILDING ENERGY COSTS USING OPTIMIZED OPERATION STRATEGIES FOR CONSTANT VOLUME AIR HANDLING SYSTEMS Mingsheng Liu, her Atha, Agarni Reddy Ed White David Claridge and Jeff Haberl Department of Physical Plant Texas A&M University...
HYPERFINE STRUCTURE CONSTANTS OF ENERGETICALLY HIGH-LYING LEVELS OF ODD PARITY OF ATOMIC VANADIUM
Güzelçimen, F.; Yap?c?, B.; Demir, G.; Er, A.; Öztürk, I. K.; Ba?ar, Gö. [Faculty of Science, Physics Department, Istanbul University, Tr-34134 Vezneciler, Istanbul (Turkey); Kröger, S. [Hochschule für Technik und Wirtschaft Berlin, Wilhelminenhofstrasse 75A, D-12459 Berlin (Germany); Tamanis, M.; Ferber, R.; Docenko, D. [Laser Centre and Institute of Astronomy, The University of Latvia, Rainis Boulevard 19, LV-1586 Riga (Latvia); Ba?ar, Gü., E-mail: gbasar@istanbul.edu.tr, E-mail: sophie.kroeger@htw-berlin.de [Faculty of Science and Letters, Physics Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey)
2014-09-01T23:59:59.000Z
High-resolution Fourier transform spectra of a vanadium-argon plasma have been recorded in the wavelength range of 365-670 nm (15,000-27,400 cm{sup –1}). Optical bandpass filters were used in the experimental setup to enhance the sensitivity of the Fourier transform spectrometer. In total, 138 atomic vanadium spectral lines showing resolved or partially resolved hyperfine structure have been analyzed to determine the magnetic dipole hyperfine structure constants A of the involved energy levels. One of the investigated lines has not been previously classified. As a result, the magnetic dipole hyperfine structure constants A for 90 energy levels are presented: 35 of them belong to the configuration 3d {sup 3}4s4p and 55 to the configuration 3d {sup 4}4p. Of these 90 constants, 67 have been determined for the first time, with 23 corresponding to the configuration 3d {sup 3}4s4p and 44 to 3d {sup 4}4p.
Decay constants of heavy-light vector mesons from QCD sum rules
Patrick Gelhausen; Alexander Khodjamirian; Alexei A. Pivovarov; Denis Rosenthal
2015-03-27T23:59:59.000Z
We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons B^*_(s) and D^*_(s) we improve the accuracy of OPE, taking into account the O(alpha_s^2) terms in the perturbative part and calculating the O(alpha_s) corrections to the quark-condensate contribution. With this accuracy, we obtain the ratios of decay constants: f_B^*/f_B=1.02 +0.07 -0.03, f_D^*/f_D=1.20 +0.10 -0.07. The sum rule predictions for the decay constants of pseudoscalar mesons are updated with the results f_B=(207 +17 -9) MeV, f_B_s=(242 +17 -12) MeV, f_D=(201 +12 -13) MeV, f_D_s=(238 +13 -23) MeV. In order to assess the sensitivity of our calculation to the form of the sum rule, we consider alternative versions such as the power moments and Borel sum rules with different weights of the spectral density. We also investigated the heavy quark limit of the sum rules for vector and pseudoscalar mesons, estimating the violations of the heavy-quark spin and flavour symmetry.
New approaches for modeling type Ia supernovae
Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan
2007-01-01T23:59:59.000Z
runaway in Type Ia supernovae: How to run away? oIgnition in Type Ia Supernovae. II. A Three- dimensionalnumber modeling of type Ia supernovae. I. hydrodynamics.
see Type I decision error see Type II decision error
-1, 12, 22; 4-11; 5-46 to 51; 7-7; 8-1, 2, 15, 16, 22, 24, 27; A-5; N-16 areas 2-5 HSA/scoping 2 INDEX see Type I decision error see Type II decision error 91b material 3-5 Amin area-25; 8-11, 17 area evaluation & HSA 3-11 classification 2-4, 5, 17, 28; 4-11 contaminated 2-3 land
Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)
1997-01-01T23:59:59.000Z
Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.
Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.
1997-08-12T23:59:59.000Z
Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.
Dettmann, Carl
T and the adiabatic transforma- tions are at constant S. Thus a Carnot cycle is simply a rectangle in (S, T) space. 2 raising of temperature by an infinite number of heat baths is a reversible process; reversible processes this reversibly, and obtain the maximum amount of work. 6. We have (from the first law at constant N) dS = d
Truong, Thanh N.
-flux correlation function for calculating the thermal rate constants of chemical reactions in solution in this study would provide a complete tool for studying the quantum dynamics of chemical reactions the thermal chemical reaction rate constants. Furthermore, we also employ an efficient and accurate quantum
INDIVIDUAL STAY CONTRACT SUMMER HOUSING 2014
Latiolais, M. Paul
. #210, Portland, OR 97201 Ph:(503)725-4336 Fax:(503)725-4394 shc@pdx.edu 1 OFFICE USE ONLY Date)725-4336 Fax:(503)725-4394 shc@pdx.edu 2 5. GENERAL PREFERENCES The Summer Housing and Conferencing contract
Security system helps utility stay competitive
NONE
1995-04-01T23:59:59.000Z
Atlantic Electric is saving more than $750,000 annually in security costs by using an innovative closed-circuit television (CCTV) system to guard its remote sites electronically. Today, a single guard in the central security control room at Atlantic Electric`s headquarters electronically surveys and controls some 20 remote sites such as combustion turbine sites, material storage, administrative facilities and operating centers. Protecting these sites are CCTV cameras mounted around each yard, floodlighting, and a motion detection and signal transmission system called Adpro SiteWatch by vsion Systems Inc. The SiteWatch system automatically displays to the central guard any intrusion at a site, and captures and replays the intrusion events similar to an instant replay in a televised sporting event. Over the five year transition, Atlantic Electric saved nearly $2 million in security costs.
Microsoft Word - Final stay rate 03.doc
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville PowerTariff Pages default SignEnergy Michigan:RECORD OFNews Media April 13, Hanford1495Â«Customer11
Staying Current: Changes & Updates September 4, 2013
Kay, Mark A.
Self-Inspection Expectations · SC County Hazardous Waste Updates and Expectations · EHS Updates deficiencies üSeparate form for areas requiring a monthly inspection http://www.stanford Hazardous Materials Compliance Division(HMCD) 1555 Berger Drive, Suite 300, San Jose, CA 95112-2716 Phone
stay healthy, my friends PREVENT THE SPREAD
Akhmedov, Azer
secretions by close personal contact, such as coughing, sharing drinks, and kissing, or being in close NOT cough into anyone's face. Cough into your sleeve or tissue. Wash or sanitize hands frequently. drinking
Leading hadronic contributions to the running of the electroweak coupling constants from lattice QCD
Burger, Florian; Petschlies, Marcus; Pientka, Grit
2015-01-01T23:59:59.000Z
The quark-connected leading-order hadronic contributions to the running of the electromagnetic fine structure constant, $\\alpha_{\\rm QED}$, and the weak mixing angle, $\\theta_W$, are determined by a four-flavour lattice QCD computation with twisted mass fermions. Full agreement of the results with a phenomenological analysis is observed with an even comparable statistical uncertainty. We show that the uncertainty of the lattice calculation is dominated by systematic effects which then leads to significantly larger errors than obtained by the phenomenological analysis.
Leading hadronic contributions to the running of the electroweak coupling constants from lattice QCD
Florian Burger; Karl Jansen; Marcus Petschlies; Grit Pientka
2015-05-13T23:59:59.000Z
The quark-connected leading-order hadronic contributions to the running of the electromagnetic fine structure constant, $\\alpha_{\\rm QED}$, and the weak mixing angle, $\\theta_W$, are determined by a four-flavour lattice QCD computation with twisted mass fermions. Full agreement of the results with a phenomenological analysis is observed with an even comparable statistical uncertainty. We show that the uncertainty of the lattice calculation is dominated by systematic effects which then leads to significantly larger errors than obtained by the phenomenological analysis.
From the Cosmological Constant: Higgs Boson, Dark Matter, and Quantum Gravity Scales
James R. Bogan
2010-11-08T23:59:59.000Z
We suggest discovery targets for the Higgs boson, dark matter, and quantum gravity mass scales, motivated by the Dirac equation for the electron in deSitter space, and a sixth-order constraint between the electron QED parameters and the cosmological constant. We go on to show that this constraint can be viewed as a structural parameter of the electron, and leads naturally to a new cosmic horizon. A dual fourth-order constraint implies a second-order one, from which the electron neutrino mass is derived.
Non-perturbative computation of the strong coupling constant on the lattice
Rainer Sommer; Ulli Wolff
2015-01-08T23:59:59.000Z
We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically carry out the required multiscale non-perturbative calculation with our special emphasis on the control of systematic errors are summarized. The complete results in the two dynamical flavor approximation are reviewed and an outlook is given on the ongoing three flavor extension of the programme with improved target precision.
ODEs, Homework #3 1. Suppose A, B are constant square matrices such that etA
Karageorgis, Paschalis
ODEs, Homework #3 Solutions 1. Suppose A, B are constant square matrices such that etA etB = et identity with respect to t, we find that etA etB = et(A+B) = AetA etB + etA BetB = (A + B)et(A+B) . Differentiating once again, we now get A2 etA etB + AetA BetB + AetA BetB + etA B2 etB = (A + B)2 et(A+B) so we
Jamie M. Foster; Dmitry E. Pelinovsky
2015-06-16T23:59:59.000Z
We consider the slow nonlinear diffusion equation subject to a constant absorption rate and construct local self-similar solutions for reversing (and anti-reversing) interfaces, where an initially advancing (receding) interface gives way to a receding (advancing) one. We use an approach based on invariant manifolds, which allows us to determine the required asymptotic behaviour for small and large values of the concentration. We then `connect' the requisite asymptotic behaviours using a robust and accurate numerical scheme. By doing so, we are able to furnish a rich set of self-similar solutions for both reversing and anti-reversing interfaces.
Identification of Bulk coupling constant in Higher Spin/ABJ correspondence
Honda, Masazumi
2015-01-01T23:59:59.000Z
We study the conjectured duality between the $\\mathcal{N}=6$ Vasiliev higher spin theory on $AdS_4$ and 3d $\\mathcal{N}=6$ superconformal Chern-Simons matter theory known as the ABJ theory. We discuss how the parameters in the ABJ theory should be related to the bulk coupling constant in the Vasiliev theory. For this purpose, we compute two-point function of stress tensor in the ABJ theory by using supersymmmetry localization. Our result justifies the proposal by arXiv:1504.00365 and determine the unknown coefficient in the previous work.
Identification of Bulk coupling constant in Higher Spin/ABJ correspondence
Masazumi Honda
2015-06-16T23:59:59.000Z
We study the conjectured duality between the $\\mathcal{N}=6$ Vasiliev higher spin theory on $AdS_4$ and 3d $\\mathcal{N}=6$ superconformal Chern-Simons matter theory known as the ABJ theory. We discuss how the parameters in the ABJ theory should be related to the bulk coupling constant in the Vasiliev theory. For this purpose, we compute two-point function of stress tensor in the ABJ theory by using supersymmmetry localization. Our result justifies the proposal by arXiv:1504.00365 and determine the unknown coefficient in the previous work.
Testing of Dark Energy and a Solution of the Cosmological Constant Problem
Vladimir Burdyuzha
2014-01-19T23:59:59.000Z
A probable solution of the cosmological constant problem was recently found. We propose that dark energy of the Universe is vacuum energy. Our Universe during its expansion is spending its vacuum energy for creation of new quantum states, but in the quantum regime phase transitions were more effective in reducing the vacuum energy than creation of new quantum states. Here we show how the 123 crisis orders of the vacuum energy are reduced by conventional physical processes in both the quantum and classical regimes of the Universe evolution. Numeral estimates of dark energy evolution are also presented.
On the vacuum fluctuations and the cosmological constant: Comment on the paper by T.Padmanabhan
V. G. Gurzadyan; S. -S. Xue
2006-03-05T23:59:59.000Z
The formula for the dark energy, derived by Padmanabhan in a recent Letter to Editor (Class.Quantum Grav. September 2005, the formula given in its Abstract), was actually derived 4 years earlier ourselves in astro-ph/0105245; Mod.Phys.Lett. A18, 561, 2003. Among dozens of references in that Letter, no quotation to our paper. Based on the same Zeldovich idea on vacuum fluctuations, Padmanabhan derives it from scaling considerations, while we had gone into more details and shown that the formula fits the observed value of the cosmological constant if l=0 modes are relevant.
Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field
Casada, Donald A. (Knoxville, TN); Haynes, Howard D. (Knoxville, TN)
1993-01-01T23:59:59.000Z
One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.
Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant
MuLan Collaboration; D. B. Chitwood; T. I. Banks; M. J. Barnes; S. Battu; R. M. Carey; S. Cheekatmalla; S. M. Clayton; J. Crnkovic; K. M. Crowe; P. T. Debevec; S. Dhamija; W. Earle; A. Gafarov; K. Giovanetti; T. P. Gorringe; F. E. Gray; M. Hance; D. W. Hertzog; M. F. Hare; P. Kammel; B. Kiburg; J. Kunkle; B. Lauss; I. Logashenko; K. R. Lynch; R. McNabb; J. P. Miller; F. Mulhauser; C. J. G. Onderwater; C. S. Ozben; Q. Peng; C. C. Polly; S. Rath; B. L. Roberts; V. Tishchenko; G. D. Wait; J. Wasserman; D. M. Webber; P. Winter; P. A. Zolnierczuk
2008-02-08T23:59:59.000Z
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.
Majumdar, AK; Khatua, PK; Rathnayaka, KDD; Naugle, Donald G.
2004-01-01T23:59:59.000Z
. INTRODUCTION The Hall resistivity srHd in a crystalline ferromagnet is, for T!Tc, given by1 rH = R0B + m0RsMs, s1d where B is the magnetic induction and m0 is the permeability of free space. The Lorentz force acting on the charge carriers is responsible... as the ?extraordinary? or the ?spontaneous? Hall constant. In Eq. (1) R0 and Rs have the same units of Vm/T in SI. Two different mechanisms are responsible for Rs. A. Nonclassical transport It has been shown1 that whenever the dimensionless pa- rameter " /t...
Quintessential inflation from a variable cosmological constant in a 5D vacuum
Agustin Membiela; Mauricio Bellini
2007-05-16T23:59:59.000Z
We explore an effective 4D cosmological model for the universe where the variable cosmological constant governs its evolution and the pressure remains negative along all the expansion. This model is introduced from a 5D vacuum state where the (space-like) extra coordinate is considered as noncompact. The expansion is produced by the inflaton field, which is considered as nonminimally coupled to gravity. We conclude from experiental data that the coupling of the inflaton with gravity should be weak, but variable in different epochs of the evolution of the universe.
Running couplings and operator mixing in the gravitational corrections to coupling constants
Anber, Mohamed M. [Department of Physics, University of Toronto, Toronto, Ontario, M5S1A7 (Canada); Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Donoghue, John F. [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); El-Houssieny, Mohamed [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Mathematics Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo (Egypt)
2011-06-15T23:59:59.000Z
The use of a running coupling constant in renormalizable theories is well known, but the implementation of this idea for effective field theories with a dimensional coupling constant is, in general, less useful. Nevertheless, there are multiple attempts to define running couplings, including the effects of gravity, with varying conclusions. We sort through many of the issues involved, most particularly the idea of operator mixing and also the kinematics of crossing, using calculations in Yukawa and {lambda}{phi}{sup 4} theories as illustrative examples. We remain in the perturbative regime. In some theories with a high permutation symmetry, such as {lambda}{phi}{sup 4}, a reasonable running coupling can be defined. However, in most cases, such as Yukawa and gauge theories, a running coupling fails to correctly account for the energy dependence of the interaction strength. As a by-product we also contrast on-shell and off-shell renormalization schemes and show that operators which are normally discarded, such as those that vanish by the equations of motion, are required for off-shell renormalization of effective field theories. Our results suggest that the inclusion of gravity in the running of couplings is not useful or universal in the description of physical processes.
Pseudoscalar Mass and Decay Constant in Lattice QCD with Exact Chiral Symmetry
Chiu, T W; Lee, J Y; Liu, P H; Chang, H J; Chiu, Ting-Wai; Hsieh, Tung-Han; Lee, Jon-Yu; Liu, Pei-Hua; Chang, Hsiu-Ju
2005-01-01T23:59:59.000Z
The masses and decay constants of pseudoscalar mesons $ D $, $ D_s $, and $ K $ are determined in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with single-plaquette action at $ \\beta = 6.1 $ on the $ 20^3 \\times 40 $ lattice, we compute point-to-point quark propagators for 30 quark masses in the range $ 0.03 \\le m_q a \\le 0.80 $, and measure the time-correlation functions of pseudoscalar and vector mesons. The inverse lattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\\pi $, while the strange quark bare mass ($ m_s a = 0.08 $), and the charm quark bare mass ($ m_c a = 0.80 $) are fixed such that the masses of the corresponding vector mesons are in good agreement with $ \\phi(1020) $ and $ J/\\psi(3097) $ respectively. Our results of pseudoscalar-meson decay constant are: $ f_K = 152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} = 266(10)(18) $ MeV [hep-ph/0506266]. The latest experimental result of $ f_{D^+} $ from CLEO [hep-ex/0508057] ...
Dependence of the dielectric constant of electrolyte solutions on ionic concentration
Gavish, Nir
2012-01-01T23:59:59.000Z
We study the dependence of the static dielectric constant of aqueous electrolyte solutions upon the concentration of salt in the solution and temperature. The model takes into account the orientation of the solvent dipoles due to the electric field created by ions, the ionic response to an applied field, and the effect of thermal fluctuations. The analysis suggests that the formation of ion pairs by a small fraction of disassociated ions can have a significant effect on the static dielectric constant. The model predicts the dielectric has the functional dependence $\\varepsilon(c)=\\varepsilon_w-\\beta L(3\\alpha c/\\beta)$ where $L$ is the Langevin function, $c$ is the salt concentration, $\\varepsilon_w$ is the dielectric of the pure water, $\\alpha$ is the total excess polarization of the ions and $\\beta$ is the relative difference between the water dipole moment and the effective dipole moment of ion pairs as weighted by the density of ion pairs and their structural rigidity. The functional form gives an extreme...
Christopher G. Jesudason
2011-01-26T23:59:59.000Z
The primary emphasis of this work on kinetics is to illustrate the a posteriori approach to applications, where focus on data leads to novel outcomes, rather than the a priori tendencies of applied analysis which imposes constructs on the nature of the observable. The secondary intention is the development of appropriate methods consonant with experimental definitions. By focusing on gradients, it is possible to determine both the average and instantaneous rate constants that can monitor changes in the rate constant with concentration changes as suggested by this theory. Here, methods are developed and discussed utilizing nonlinear analysis which does not require exact knowledge of initial concentrations. These methods are compared with those derived from standard methodology. These gradient methods are shown to be consistent with the ones from standard methods and could readily serve as alternatives for studies where there are limits or unknowns in the initial conditions, such as in the burgeoning fields of astrophysics and astrochemistry, forensics, archeology and biology . All four reactions studied exhibited semi sinusoidal-like change with reactant concentration change which standard methods cannot detect, which seems to constitute the observation of a new effect that is not predicted by current formulations, where the possibility that the observations are due to artifacts from instrumental errors or the optimization method is reasoned as unlikely since the experiments were conducted by different groups at very different times with different classes of reactions.
The hierarchy problem and the cosmological constant problem in the Standard Model
Fred Jegerlehner
2015-03-03T23:59:59.000Z
We argue that the SM in the Higgs phase does not suffer form a "hierarchy problem" and that similarly the "cosmological constant problem" resolves itself if we understand the SM as a low energy effective theory emerging from a cut-off medium at the Planck scale. We discuss these issues under the condition of a stable Higgs vacuum, which allows to extend the SM up to the Planck length. The bare Higgs boson mass then changes sign below the Planck scale, such the the SM in the early universe is in the symmetric phase. The cut-off enhanced Higgs mass term as well as the quartically enhanced cosmological constant term trigger the inflation of the early universe. The coefficients of the shift between bare and renormalized Higgs mass as well as of the shift between bare and renormalized vacuum energy density exhibit close-by zeros at some point below the Planck scale. The zeros are matching points between short distance and the renormalized low energy quantities. Since inflation tunes the total energy density to take the critical value of a flat universe Omega_tot=rho_tot/rho_crit=Omega_Lambda+Omega_matter+Omega_radiation}=1 it is obvious that Omega_Lambda today is of order Omega_tot given that 1>Omega_matter, Omega_radiation>0, which saturate the total density to about 26 % only, the dominant part being dark matter(21 %).
de Baubigny, Julien Dupré; Fabié, Laure; Delmas, Mathieu; Aimé, Jean-Pierre; Legros, Marc; Ondarçuhu, Thierry
2015-01-01T23:59:59.000Z
We investigate the shape and mechanical properties of liquid interfaces down to nanometer scale by atomic force microscopy (AFM) and scanning electron microscopy (SEM) combined with in situ micromanipulation techniques. In both cases, the interface is probed with a cylindrical nanofiber with radius R of the order of 25-100 nm. The effective spring constant of the nanomeniscus oscillated around its equilibrium position is determined by static and frequency-modulation (FM) AFM modes. In the case of an unbounded meniscus, we find that the effective spring constant k is proportional to the surface tension {\\gamma} of the liquid through k = (0.51 +- 0.06) {\\gamma}, regardless of the excitation frequency from quasistatic up to 450 kHz. A model based on the equilibrium shape of the meniscus reproduces well the experimental data. Electron microscopy allowed to visualize the meniscus profile around the fiber with a lateral resolution of the order of 10 nm and confirmed its catenary shape. The influence of a lateral co...
Variation of lattice constant and cluster formation in GaAsBi
Puustinen, J.; Schramm, A.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland); Wu, M.; Luna, E. [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)] [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Laukkanen, P. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Laitinen, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)] [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)
2013-12-28T23:59:59.000Z
We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220–315 °C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 °C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out of the layer during annealing. However, dark-field and Z-contrast transmission electron microscopy analyses revealed the formation of GaAsBi clusters with a Bi content higher than in the surrounding matrix, as well as the presence of metallic As clusters. The apparent reduction of the lattice constant can be explained by a two-fold process: the diffusion of the excess As incorporated within As{sub Ga} antisites to As clusters, and the reduction of the Bi content in the GaAs matrix due to diffusion of Bi to GaAsBi clusters. Diffusion of both As and Bi are believed to be assisted by the native point defects, which are present in the low-temperature as-grown material.
Predicting the cosmological constant with the scale-factor cutoff measure
De Simone, Andrea; Guth, Alan H. [Center for Theoretical Physics, Laboratory for Nuclear Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Salem, Michael P.; Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)
2008-09-15T23:59:59.000Z
It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant {lambda} gives a reasonable fit to observation. However, a realistic model of the multiverse has a physical volume that diverges with time, and the predicted distribution of {lambda} depends on how the spacetime volume is regulated. A very promising method of regulation uses a scale-factor cutoff, which avoids a number of serious problems that arise in other approaches. In particular, the scale-factor cutoff avoids the 'youngness problem' (high probability of living in a much younger universe) and the 'Q and G catastrophes' (high probability for the primordial density contrast Q and gravitational constant G to have extremely large or small values). We apply the scale-factor cutoff measure to the probability distribution of {lambda}, considering both positive and negative values. The results are in good agreement with observation. In particular, the scale-factor cutoff strongly suppresses the probability for values of {lambda} that are more than about 10 times the observed value. We also discuss qualitatively the prediction for the density parameter {omega}, indicating that with this measure there is a possibility of detectable negative curvature.
Reduction of iron-oxide-carbon composites: part I. Estimation of the rate constants
Halder, S.; Fruehan, R.J. [Praxair Inc., Tonawanda, NY (United States). Technological Center
2008-12-15T23:59:59.000Z
A new ironmaking concept using iron-oxide-carbon composite pellets has been proposed, which involves the combination of a rotary hearth furnace (RHF) and an iron bath smelter. This part of the research focuses on studying the two primary chemical kinetic steps. Efforts have been made to experimentally measure the kinetics of the carbon gasification by CO{sub 2} and wustite reduction by CO by isolating them from the influence of heat- and mass-transport steps. A combined reaction model was used to interpret the experimental data and determine the rate constants. Results showed that the reduction is likely to be influenced by the chemical kinetics of both carbon oxidation and wustite reduction at the temperatures of interest. Devolatilized wood-charcoal was observed to be a far more reactive form of carbon in comparison to coal-char. Sintering of the iron-oxide at the high temperatures of interest was found to exert a considerable influence on the reactivity of wustite by virtue of altering the internal pore surface area available for the reaction. Sintering was found to be predominant for highly porous oxides and less of an influence on the denser ores. It was found using an indirect measurement technique that the rate constants for wustite reduction were higher for the porous iron-oxide than dense hematite ore at higher temperatures (> 1423 K). Such an indirect mode of measurement was used to minimize the influence of sintering of the porous oxide at these temperatures.
Alberto A. Garcia Diaz
2014-12-17T23:59:59.000Z
Under the hydrodynamic equilibrium Buchdahl's conditions on the behavior of the density and the pressure, for regular fluid static circularly symmetric star in (2 + 1) dimensions in the presence of a cosmological constant, is established that there are no bounds from below on the pressure and also on the mass, except for their positiveness. The metric for a constant density distribution is derived and its matching with the external static solution with a negative cosmological constant is accomplished. Some mistakes of previous works on the topic are pointed out.
Pramod Kumar Singh; Amreesh Chandra
2003-04-21T23:59:59.000Z
The dispersal of high dielectric constant ferroelectric ceramic material Ba(0.7)Sr(0.3)TiO(3) (Tc~30 C) and Ba(0.88)Sr(0.12)TiO(3) (Tc~90 C) in an ion conducting polymer electrolyte (PEO:NH4I) is reported to result in an increase in the room temperature ionic conductivity by two orders of magnitude. The conductivity enhancememt "peaks" as we approach the dielectric phase transition of the dispersed ferroelectric material where the dielectric constant changes from ~ 2000 to 4000. This establishes the role of dielectric constant of the dispersoid in enhancing the ionic conductivity of the polymeric composites.
Type Checking Type Classes Tobias Nipkow and Christian Prehofer
. The judgement : fC1 ::: Cng is a compact form of the conjunction : C1 ^ ::: ^ : Cn. Alternatively we may think of fC1 ::: Cng as a notation for C1 \\ :::\\ Cn, the intersection of the types belonging to the classes C
Type Ia Supernova Explosion Models
W. Hillebrandt; J. C. Niemeyer
2000-06-21T23:59:59.000Z
Because calibrated light curves of Type Ia supernovae have become a major tool to determine the local expansion rate of the Universe and also its geometrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe that perhaps most Type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling Type Ia supernovae as well as several of the still open questions are addressed in this review. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.
Hydrogen and helium traces in type Ib-c supernovae
A. Elmhamdi; I. J. Danziger; D. Branch; B. Leibundgut; E. Baron; R. P. Kirshner
2006-04-04T23:59:59.000Z
The spectroscopic properties of a selected optical photospheric spectra of core collapse supernovae (CCSNe) are investigated.Special attention is devoted to traces of hydrogen at early phases. The generated spectra are found to match the observed ones reasonably well, including a list of only 23 candidate ions. Guided by SN Ib 1990I, the observed trough near 6300\\AA is attributed to H$\\alpha$ in almost all Type Ib events, although in some objects it becomes too weak to be discernible, especially at later phases. Alternative line identifications are discussed. Differences in the way hydrogen manifests its presence within CCSNe are highlighted. In Type Ib SNe, the H$\\alpha$ contrast velocity (i.e. line velocity minus the photospheric velocity) seems to increase with time at early epochs, reaching values as high as 8000 km s$^{-1}$ around 15-20 days after maximum and then remains almost constant. The derived photospheric velocities, indicate a lower velocity for Type II SNe 1987A and 1999em as compared to SN Ic 1994I and SN IIb 1993J, while Type Ib events display a somewhat larger variation. The scatter, around day 20, is measured to be $\\sim$5000 km s$^{-1}$. Following two simple approaches, rough estimates of ejecta and hydrogen masses are given. A mass of hydrogen of approximately 0.02 $M_\\odot$ is obtained for SN 1990I, while SNe 1983N and 2000H ejected $\\sim$0.008 $M_\\odot$ and $\\sim$0.08 $M_\\odot$ of hydrogen, respectively. SN 1993J has a higher hydrogen mass, $\\sim 0.7$ $M_\\odot$ with a large uncertainty. A low mass and thin hydrogen layer with very high ejection velocities above the helium shell, is thus the most likely scenario for Type Ib SNe. Some interesting and curious issues relating to oxygen lines suggest future investigations.
On Measuring the Metallicity of Supernovae Type Ia Progenitors
Miles, Broxton J; Townsley, Dean M; Timmes, F X; Jackson, Aaron P; Calder, Alan C; Brown, Edward F
2015-01-01T23:59:59.000Z
In Type Ia Supernovae (\\sneia), the relative abundances of chemical elements are affected by the neutron excess in the composition of the progenitor white dwarf. Since these products leave signatures in the spectra near maximum light, spectral features may be used to constrain the composition of the progenitor. We calculate the nucleosynthetic yields for three \\snia simulations for a wide range of progenitor metallicities, and calculate synthetic light curves and spectra to explore correlations between progenitor metallicity and the strength of spectral features. We use two 2D simulations of the deflagration-detonation-transition scenario with different $^{56}$Ni yields and the W7 simulation to control for differences between explosion models and total yields. While the overall yields of intermediate mass elements (16 $<$ A $\\leq$ 40) differ between the three cases, trends in the yields are similar. With increasing metallicity, $^{28}$Si yields remain nearly constant, $^{40}$Ca yields decline, and Ti and $...
Varghese, Joshua
2011-08-02T23:59:59.000Z
constant (TC) have been developed. The axial strain TC is a parameter that is related to the viscoelastic and poroelastic behavior of tissues. Estimation of this parameter can be done using curve fitting methods. However, the effect of temporal...
Varghese, Joshua
2011-08-02T23:59:59.000Z
constant (TC) have been developed. The axial strain TC is a parameter that is related to the viscoelastic and poroelastic behavior of tissues. Estimation of this parameter can be done using curve fitting methods. However, the effect of temporal...
Furr, Howard L.
1948-01-01T23:59:59.000Z
, k-15 eguivalent lane loading was used in the analysis. Girder design wms confined to interior girders, end the design was based on bending moment analyses only. Continuous girders of standard constant section and of rein" orced section were...
How precisely can we determine the pion-nucleon coupling constant from the isovector GMO sum rule?
B. Loiseau; T. E. O. Ericson; A. W. Thomas
2000-02-04T23:59:59.000Z
The isovector GMO sum rule for zero energy forward pion-nucleon scattering is critically studied to obtain the charged pion-nucleon coupling constant using the precise negatively charged pion-proton and pion-deuteron scattering lengths deduced recently from pionic atom experiments. This direct determination leads to a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09 (statistic) +- 0.17 (systematic). We obtain also accurate values for the pion-nucleon scattering lengths.
How Precisely can we Determine the $\\piNN$ Coupling Constant from the Isovector GMO Sum Rule?
Loiseau, B; Thomas, A W
1999-01-01T23:59:59.000Z
The isovector GMO sum rule for zero energy forward pion-nucleon scattering iscritically studied to obtain the charged pion-nucleon coupling constant usingthe precise negatively charged pion-proton and pion-deuteron scattering lengthsdeduced recently from pionic atom experiments. This direct determination leadsto a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09(statistic) +- 0.17 (systematic). We obtain also accurate values for thepion-nucleon scattering lengths.
Browne, Michael
2010-07-14T23:59:59.000Z
. ................................................................... 26 Fig. 6. a)Entire Driveshaft Assembly, b) Constant Velocity Joint at PTU/Transaxle End of Driveshaft, c) Center Bearing Assembly with Non=Constant Velocity Joint, and d) Axle End of Driveshaft.... .......................................................... 36 Fig. 13. Order Comparison for a) 2nd Order, b) 4th Order, c) 6th Order, and d) 8th Order with Misalignment Angles of 0 (blue), 2(red), and 4 Degrees (magenta...
Krein Quantization Approach to the Vacuum Energy and Cosmological Constant Problem
H. Pejhan; S. Rahbardehghan
2014-12-30T23:59:59.000Z
In this paper, we consider a new version of indefinite metric field quantization called "Krein" quantization approach. Centering on the vacuum energy, fundamental subjects revolve around this concept will be discussed. In this approach, vacuum expectation value of the energy-momentum tensor can be defined properly and uniquely. Actually, no infinite term appears and the vacuum energy of the free field vanishes. These properties allow us to propose a discussion which creates an interesting link to cosmological constant problem. Achieving this goal, however, necessitates consistency of the theory with conventional ones, so we have studied and made comparison essential issues such as unitarity of the theory and the trace anomaly subject. It is specifically debated that Krein construction does not destroy black holes thermodynamics.
Measuring the Boltzmann constant by mid-infrared laser spectroscopy of ammonia
Mejri, S; Kozlova, O; Ayari, C; Tokunaga, Sean; Chardonnet, C; Briaudeau, S; Darquié, B; Rohart, F; Daussy, C
2015-01-01T23:59:59.000Z
We report on our ongoing effort to measure the Boltzmann constant, $k_B,$ using the Doppler broadening technique on ammonia. This paper presents some of the improvements made to the mid-infrared spectrometer including the use of a phase-stabilized quantum cascade laser, a lineshape analysis based on a refined physical model and an improved fitting program 2 increasing the confidence in our estimates of the relevant molecular parameters, and a first evaluation of the saturation parameter and its impact on the measurement of k B. A summary of the systematic effects contributing to the measurement is given and the optimal experimental conditions for mitigating those effects in order to reach a competitive measurement of $k_B$ at a part per million accuracy level are outlined.
Measuring the Boltzmann constant by mid-infrared laser spectroscopy of ammonia
S. Mejri; Papa Sow; O. Kozlova; C. Ayari; Sean Tokunaga; C. Chardonnet; S. Briaudeau; B. Darquié; F. Rohart; C. Daussy
2015-06-05T23:59:59.000Z
We report on our ongoing effort to measure the Boltzmann constant, $k_B,$ using the Doppler broadening technique on ammonia. This paper presents some of the improvements made to the mid-infrared spectrometer including the use of a phase-stabilized quantum cascade laser, a lineshape analysis based on a refined physical model and an improved fitting program 2 increasing the confidence in our estimates of the relevant molecular parameters, and a first evaluation of the saturation parameter and its impact on the measurement of k B. A summary of the systematic effects contributing to the measurement is given and the optimal experimental conditions for mitigating those effects in order to reach a competitive measurement of $k_B$ at a part per million accuracy level are outlined.
Cosmological constant in SUGRA models with Planck scale SUSY breaking and degenerate vacua
C. D. Froggatt; R. Nevzorov; H. B. Nielsen; A. W. Thomas
2014-10-08T23:59:59.000Z
The empirical mass of the Higgs boson suggests small to vanishing values of the quartic Higgs self--coupling and the corresponding beta function at the Planck scale, leading to degenerate vacua. This leads us to suggest that the measured value of the cosmological constant can originate from supergravity (SUGRA) models with degenerate vacua. This scenario is realised if there are at least three exactly degenerate vacua. In the first vacuum, associated with the physical one, local supersymmetry (SUSY) is broken near the Planck scale while the breakdown of the SU(2)_W\\times U(1)_Y symmetry takes place at the electroweak (EW) scale. In the second vacuum local SUSY breaking is induced by gaugino condensation at a scale which is just slightly lower than \\Lambda_{QCD} in the physical vacuum. Finally, in the third vacuum local SUSY and EW symmetry are broken near the Planck scale.
Performance Analysis of Dual-Fan, Dual-Duct Constant Volume Air-Handling Units
Joo, I. S.; Liu, M.
2001-01-01T23:59:59.000Z
(23) The total fan power for the DFDD system is the sum of the hot air and cold air fan powers. Ge7 Ge7 Ge8 Ge6 Gf7Gf7Gf8 Gf6 Ge7Ge7Ge8 Ge6-+= 2, min )( d o c m mHHmHmCE G26 G26G26G26 eta Gf7Gf7 Gf8 Gf6 Gf7Gf7Gf8 Gf6 Ge7Ge7Ge8 Ge6-++ 2... (28) gives the potential fan power savings. ()Gfa Gfb Gf9 GeaGeb Ge9 -+Gf7 Gf8 Gf6Ge7 Ge8 Ge6 -+ +-= 3 3 )1(1 11 )1 oof gammagammaalpha alphaphi1 (29) SIMULATION RESULTS AND ANALYSES The simulation was conducted on a constant air volume system...
Stochastic dynamics of adhesion clusters under shared constant force and with rebinding
T. Erdmann; U. S. Schwarz
2004-05-12T23:59:59.000Z
Single receptor-ligand bonds have finite lifetimes, so that biological systems can dynamically react to changes in their environment. In cell adhesion, adhesion bonds usually act cooperatively in adhesion clusters. Outside the cellular context, adhesion clusters can be probed quantitatively by attaching receptors and ligands to opposing surfaces. Here we present a detailed theoretical analysis of the stochastic dynamics of a cluster of parallel bonds under shared constant loading and with rebinding. Analytical solutions for the appropriate one-step master equation are presented for special cases, while the general case is treated with exact stochastic simulations. If the completely dissociated state is modeled as an absorbing boundary, mean cluster lifetime is finite and can be calculated exactly. We also present a detailed analysis of fluctuation effects and discuss various approximations to the full stochastic description.
Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants
Savely G. Karshenboim
2005-09-01T23:59:59.000Z
Quantum electrodynamics is the first successful and still the most successful quantum field theory. Simple atoms, being essentially QED systems, allow highly accurate theoretical predictions. Because of their simple spectra, such atoms have been also efficiently studied experimentally frequently offering the most precisely measured quantities. Our review is devoted to comparison of theory and experiment in the field of precision physics of light simple atoms. In particular, we consider the Lamb shift in the hydrogen atom, the hyperfine structure in hydrogen, deuterium, helium-3 ion, muonium and positronium, as well as a number of other transitions in positronium. Additionally to a spectrum of unperturbed atoms, we consider annihilation decay of positronium and the g factor of bound particles in various two-body atoms. Special attention is paid to the uncertainty of the QED calculations due to the uncalculated higher-order corrections and effects of the nuclear structure. We also discuss applications of simple atoms to determination of several fundamental constants.
Soil damping constants related to common soil properties in sands and clays
Gibson, Gary Clive
1968-01-01T23:59:59.000Z
SOIL D'c~. 'I'IIIG COESTAlxI. S PI', IslTED TO CO!~i'iOI& SOII. PRO& ERTIES J3I SAE1)S AND CL?"S A Thesis by Gary Olive G'boon Sr b':I' te'I to tho Gra=lu. . te Col lope of Texas Afxl Univcrsi ty in pert'al fulfillsent of the requirenent... for the Je;, ree of YiASTER Ol" SCIEI!CE August ISSS II. ';or Subject: Civil I:nSin er. nb SOIL DAMPING CONSTANTS REIATED TO COMMON SOIL PROPERTIES IN SANDS AND CLAYS A Thesis by Gary Clive Gibson Approved as to style and content by: (Head...
Scale-invariance in gravity and implications for the cosmological constant
Bryan Kelleher
2004-04-26T23:59:59.000Z
Recently a scale invariant theory of gravity was constructed by imposing a conformal symmetry on general relativity. The imposition of this symmetry changed the configuration space from superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms - to conformal superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms and conformal transformations. However, despite numerous attractive features, the theory suffers from at least one major problem: the volume of the universe is no longer a dynamical variable. In attempting to resolve this problem a new theory is found which has several surprising and atractive features from both quantisation and cosmological perspectives. Furthermore, it is an extremely restrictive theory and thus may provide testable predictions quickly and easily. One particularly interesting feature of the theory is the resolution of the cosmological constant problem.
Can a variable gravitational constant resolve the Faint Young Sun Paradox ?
Varun Sahni; Yuri Shtanov
2014-11-05T23:59:59.000Z
Solar models suggest that four billion years ago the young Sun was about 25% fainter than it is today, rendering Earth's oceans frozen and lifeless. However, there is ample geophysical evidence that Earth had a liquid ocean teeming with life 4 Gyr ago. Since ${\\cal L_\\odot} \\propto G^7M_\\odot^5$, the Sun's luminosity ${\\cal L_\\odot}$ is exceedingly sensitive to small changes in the gravitational constant $G$. We show that a percent-level increase in $G$ in the past would have prevented Earth's oceans from freezing, resolving the faint young Sun paradox. Such small changes in $G$ are consistent with observational bounds on ${\\Delta G}/G$. Since ${\\cal L}_{\\rm SNIa} \\propto G^{-3/2}$, an increase in $G$ leads to fainter supernovae, creating tension between standard candle and standard ruler probes of dark energy. Precisely such a tension has recently been reported by the Planck team.
T. Thiemann
1999-10-04T23:59:59.000Z
We present here the canonical treatment of spherically symmetric (quantum) gravity coupled to spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate momenta, whose geometrical interpretation is explored. The dimension of the reduced phase space depends on the topology chosen, quite similar to the case of pure (2+1) gravity. We also compare the reduced phase space quantization to the algebraic quantization. Altogether, we observe that the present model serves as an interesting testing ground for full (3+1) gravity. We use the new canonical variables introduced by Ashtekar which simplifies the analysis tremendously.
T. Thiemann
1999-10-04T23:59:59.000Z
We extend here the canonical treatment of spherically symmetric (quantum) gravity to the most simple matter coupling, namely spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate momenta, whose geometrical interpretation is explored. The dimension of the reduced phase space depends on the topology chosen, quite similar to the case of pure (2+1) gravity. We investigate several conceptual and technical details that might be of interest for full (3+1) gravity. We use the new canonical variables introduced by Ashtekar, which simplifies the analysis tremendously.
Fundamental constants and their variability in theories of High Energy Physics
Thomas Dent
2008-02-12T23:59:59.000Z
The Standard Model of particle physics and the theory of General Relativity (GR) currently provide a good description of almost all phenomena of particle physics and gravitation that have received controlled experimental tests. However, the Standard Model contains many a priori variable parameters whose values, and whose apparent (near-)constancy, have yet to receive a convincing theoretical explanation. At the same time, GR may now require to be extended or altered at the largest length scales, to account for the recent apparent accelerated cosmological expansion. In this introductory review I present theoretical aspects of the search for explanations of the values and possible variations of fundamental ``constants'', focusing on the possibility of unification of interactions. I also relate cosmological variations to modifications of gravity both locally and cosmologically.
Cosmological Non-Constant Problem: Cosmological bounds on TeV-scale physics and beyond
Niayesh Afshordi; Elliot Nelson
2015-07-04T23:59:59.000Z
We study the influence of the fluctuations of a Lorentz invariant and conserved vacuum on cosmological metric perturbations, and show that they generically blow up in the IR. We compute this effect using the K\\"all\\'en-Lehmann spectral representation of stress correlators in generic quantum field theories, as well as the holographic bound on their entanglement entropy, both leading to an IR cut-off that scales as the fifth power of the highest UV scale (in Planck units). One may view this as analogous to the Heisenberg uncertainty principle, which is imposed on the phase space of gravitational theories by the Einstein constraint equations. The leading effect on cosmological observables come from anisotropic vacuum stresses which imply: i) any extension of the standard model of particle physics can only have masses (or resonances) $\\lesssim$ 35 TeV, and ii) perturbative quantum field theory or quantum gravity becomes strongly coupled beyond a cut-off scale of $\\Lambda\\lesssim1$ PeV. Such a low cut-off is independently motivated by the Higgs hierarchy problem. This result, which we dub the cosmological non-constant problem, can be viewed as an extension of the cosmological constant (CC) problem, demonstrating the non-trivial UV-IR coupling and (yet another) limitation of effective field theory in gravity. However, it is more severe than the old CC problem, as vacuum fluctuations cannot be tuned to cancel due to the positivity of spectral densities or entropy. We thus predict that future advances in cosmological observations and collider technology will sandwich from above and below, and eventually discover, new (non-perturbative) physics beyond the Standard Model within the TeV-PeV energy range.
Diederik Aerts; Marek Czachor
2005-12-22T23:59:59.000Z
An abstract DNA-type system is defined by a set of nonlinear kinetic equations with polynomial nonlinearities that admit soliton solutions associated with helical geometry. The set of equations allows for two different Lax representations: A von Neumann form and a Darboux-covariant Lax pair. We explain why non-Kolmogorovian probability models occurring in soliton kinetics are naturally associated with chemical reactions. The most general known characterization of soliton kinetic equations is given and a class of explicit soliton solutions is discussed. Switching between open and closed states is a generic behaviour of the helices. The effect does not crucially depend on the order of nonlinearity (i.e. types of reactions), a fact that may explain why simplified models possess properties occuring in realistic systems. We explain also why fluctuations based on Darboux transformations will not destroy the dynamics but only switch between a finite number of helical structures.
Tridiagonal pairs of Krawtchouk type
Ito, Tatsuro
2007-01-01T23:59:59.000Z
Let $K$ denote an algebraically closed field with characteristic 0 and let $V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$ denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has Krawtchouk type whenever the sequence $\\lbrace d-2i\\rbrace_{i=0}^d$ is a standard ordering of the eigenvalues of $A$ and a standard ordering of the eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there exists a nondegenerate symmetric bilinear form $$ on $V$ such that $= $ and $= $ for $u,v\\in V$. We show that the following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii) $A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.
Type Ia Supernovae: Spectroscopic Surprises
David Branch
2003-10-23T23:59:59.000Z
Recent observations have extended the range of diversity among spectra of Type Ia supernovae. I briefly discuss SN Ia explosion models in the spectroscopic context, the observed diversity, and some recent results from direct analysis with the Synow code for one normal and two peculiar SNe Ia. Relating the observational manifestations of diversity to their physical causes is looking like an ever more challenging problem.
Niger Delta play types, Nigeria
Akinpelu, A.O. [Chevron Nigeria Limited, Lagos (Nigeria)
1995-08-01T23:59:59.000Z
Exploration databases can be more valuable when sorted by play type. Play specific databases provide a system to organize E & P data used in evaluating the range of values of parameters for reserve estimation and risk assessment. It is important both in focusing the knowledge base and in orienting research effort. A play in this context is any unique combination of trap, reservoir and source properties with the right dynamics of migration and preservation that results in hydrocarbon accumulation. This definitions helps us to discriminate the subtle differences found with these accumulation settings. About 20 play types were identified around the Niger Delta oil province in Nigeria. These are grouped into three parts: (1) The proven plays-constituting the bulk of exploration prospects in Nigeria today. (2) The unproven or semi-proven plays usually with some successes recorded in a few tries but where knowledge is still inadequate. (3) The unproven or analogous play concept. These are untested but geologically sound ideas which may or may not have been tried elsewhere. With classification and sub grouping of these play types into specific databases, intrinsic attributes and uniqueness of each of them with respect to the four major risk elements and the eight parameters for reserve estimation can be better understood.
Measuring Boltzmann's constant with a low-cost atomic force microscope: An undergraduate experiment
Manalis, Scott
to directly control it. Its pedagogical advantage is that students interact with a complete instrument system measurements, students learn to apply numerous concepts such as digital sampling, Fourier-domain analysis designed and built an inexpen- sive atomic force microscope AFM system that enables this type of hands
Wheel-type magnetic refrigerator
Barclay, John A. (Los Alamos, NM)
1983-01-01T23:59:59.000Z
The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.
Wheel-type magnetic refrigerator
Barclay, J.A.
1982-01-20T23:59:59.000Z
The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.
Wheel-type magnetic refrigerator
Barclay, J.A.
1983-10-11T23:59:59.000Z
The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.
A. W. Beckwith
2004-08-10T23:59:59.000Z
The tunneling Hamiltonian has proven to be a useful method in many body physics to treat particle tunneling between different states represented as wavefunctions. Here we apply a generalization of the way we formed appropriate wave functionals for charge density waves to how to present nucleation of an inflationary universe. This allows us to make a first order phase transition to initiate nucleation of an inflationary universe, in which tunneling between states which are wave functionals of a scalar quantum field are considered. Our prior article showed us how we can have particle - anti particle pairs as a model of how nucleation occurs and construct a potential which may permit formation of dark matter, using Sherrers k essence model construction. This same construction permits a definitive analysis of when conditions for pure cosmological constant behavior but no growth of density pertubations occur, largely as a matter of change of slope of a soliton-anti soliton pair during the nucleation process of a new universe.
Bohr - Planck quantum theory, (Tesla) magnetic monopoles and fine structure constant
Vladan Pankovic; Darko V. Kapor; Stevica Djurovic; Miodrag Krmar
2014-10-17T23:59:59.000Z
In this work we apply Bohr-Planck (Old quantum atomic and radiation) theory, i.e. and quasi-classical methods for analysis of the magnetic monopoles and other problems. We reproduce exactly some basic elements of the Dirac magnetic monopoles theory, especially Dirac electric/magnetic charge quantization condition. Also, we suggest a new, effective, simply called Tesla model (for analogy with positions of the solenoids by Tesla inductive motor) of the magnetic monopole instead of usual effective Dirac model (half-infinite, very tinny solenoid) of the magnetic monopole. In our, i.e. Tesla model we use three equivalent tiny solenoids connected in series with a voltage source. One end of any solenoid is placed at the circumference of a circle and solenoids are directed radial toward circle center. Length of any solenoid is a bit smaller than finite circle radius so that other end of any solenoid is very close to the circle center. Angles between neighboring solenoids equal $120^{\\circ}$. All this implies that, practically, there is no magnetic field, or, magnetic pole, e.g. $S$, in the circle center, and that whole system holds only other, $N$ magnetic pole, at the ends of the solenoids at circle circumference. Finally, we reproduce relatively satisfactory value of the fine structure constant using Planck, i.e. Bose-Einstein statistics and Wien displacement law.