Variable-Period Undulators For Synchrotron Radiation
Shenoy, Gopal (Naperville, IL); Lewellen, John (Plainfield, IL); Shu, Deming (Darien, IL); Vinokurov, Nikolai (Novosibirsk, RU)
2005-02-22
A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.
Short-Period RF Undulator for a SASE Nanometer source
Jay L. Hirshfield
2001-12-21
Analysis is described towards development of a RF undulator with a period < 1 cm, an undulator parameter K of the order of unity, and a gap greater than 2.25 mm. The application for the undulator is for a SASE source to produce 1 nm wavelength radiation using a low energy electron beam in the range 1-2 GeV. Particle orbit calculations in a conventional standing-wave resonator configuration show that the presence of a co-propagating component of RF field can cause deleterious motion for the undulating electrons that can seriously degrade their radiation spectrum. To obviate this problem, resonator designs were devised in which only the counter-propagating field components interact with the particles. Two resonator configurations with the same undulator parameter K = 0.4 have been devised and are described in this report.
Investigations on Important Properties of the 10 cm x 10 cm GEM Prototype
Saenboonruang, Kiadtisak; Kulasri, Kittipong; Ritthirong, Anawat
2015-01-01
The Gas Electron Multiplier (GEM) detector is one of promising particle and radiation detectors that has been improved greatly from previous gas detectors. The improvement includes better spatial resolutions, higher detection rate capabilities, and flexibilities in designs. In particular, the 10 cm x 10 cm GEM prototype is designed and provided by the Gas Detectors Development group (GDD) at CERN, Switzerland. With its simplicity in operations and designs, while still maintaining high qualities, the GEM prototype is suitable for both start-up and advanced researches. This article aims to report the investigations on some important properties of the 10 cm x 10 cm GEM detector using current measurement and signal counting. Results have shown that gains of the GEM prototype exponentially increase as voltage supplied to the detector increases, while the detector reaches full efficiency (plateau region) when the voltage is greater than 4100 V. In terms of signal sharing between X and Y strips of the readout, X str...
Investigations on Important Properties of the 10 cm x 10 cm GEM Prototype
Kiadtisak Saenboonruang; Piyakul Kumphiranon; Kittipong Kulasri; Anawat Ritthirong
2015-10-27
The Gas Electron Multiplier (GEM) detector is one of promising particle and radiation detectors that has been improved greatly from previous gas detectors. The improvement includes better spatial resolutions, higher detection rate capabilities, and flexibilities in designs. In particular, the 10 cm x 10 cm GEM prototype is designed and provided by the Gas Detectors Development group (GDD) at CERN, Switzerland. With its simplicity in operations and designs, while still maintaining high qualities, the GEM prototype is suitable for both start-up and advanced researches. This article aims to report the investigations on some important properties of the 10 cm x 10 cm GEM detector using current measurement and signal counting. Results have shown that gains of the GEM prototype exponentially increase as voltage supplied to the detector increases, while the detector reaches full efficiency (plateau region) when the voltage is greater than 4100 V. In terms of signal sharing between X and Y strips of the readout, X strips, which is on the top layer of the readout, collect ~57% of the total signal. For the uniformity test, the GEM prototype has slightly higher efficiencies at the center of the detector and decreases as positions are closer to edges.
Csonka, Paul L. (Eugene, OR); Tatchyn, Roman O. (Palo Alto, CA)
1989-01-24
Micropole undulators for use in the generation of x-rays from moving charged particles and methods for manufacturing such undulators are disclosed. One type of micropole undulator has two jaws containing rows of spaced apart poles arranged so that each pole produces a magnetic field aligned with all other similar fields. An external biasing field extends through the jaws so that an overall undulator field of substantially sinusoidal shape and substantially zero average value extends along the undulator axis. Preferably, the poles are bars formed of a magnetizable, but unmagnetized, material so that, after the jaws are assembled, all of the bars can be magnetized simultaneously in a uniform magnetic field of suitable strength. Another type of micropole undulator incorporates two parallel layers which have been magnetized to provide rows of alternating magnetic fields extending in opposite directions, the layers being positioned between the pole faces of a highly magnetically permeable material with the south poles of one layer opposite the north poles of the other. Poles in the layers are formed by subjecting successive regions of each layer to oppositely directed and suitably varied magnetizing forces.
Csonka, P.L.; Tatchyn, R.O.
1989-01-24
Micropole undulators for use in the generation of x-rays from moving charged particles and methods for manufacturing such undulators are disclosed. One type of micropole undulator has two jaws containing rows of spaced apart poles arranged so that each pole produces a magnetic field aligned with all other similar fields. An external biasing field extends through the jaws so that an overall undulator field of substantially sinusoidal shape and substantially zero average value extends along the undulator axis. Preferably, the poles are bars formed of a magnetizable, but unmagnetized, material so that, after the jaws are assembled, all of the bars can be magnetized simultaneously in a uniform magnetic field of suitable strength. Another type of micropole undulator incorporates two parallel layers which have been magnetized to provide rows of alternating magnetic fields extending in opposite directions, the layers being positioned between the pole faces of a highly magnetically permeable material with the south poles of one layer opposite the north poles of the other. Poles in the layers are formed by subjecting successive regions of each layer to oppositely directed and suitably varied magnetizing forces. 16 figs.
Gottschalk, Steven C. [STI, Washington, USA; Benson, Steven V. [JLAB; Moore, Steven Wesley [JLAB
2013-05-01
Recently the JLAB FEL has demonstrated 150 W at 400 nm and 200 W at 700 nm using a 33mm period undulator designed and built by STI Optronics. This paper describes the undulator design and performance. Two key requirements were low phase error, zero steering and offset end fields and small rms trajectory errors. We will describe a new genetic algorithm that allowed phase error minimization to 1.8 degrees while exceeding specifications. The mechanical design, control system and EPICS interface will also be summarized.
Tatchyn, Roman O. (Palo Alto, CA); Csonka, Paul L. (Eugene, OR); Cremer, Jay T. (Burlingame, CA)
1990-12-11
Micropole undulators for use in the generation of x-rays from moving charged particles are disclosed. Two rows of spaced apart poles are arranged so that each pole produces a magnetic field aligned with all other similar fields. The poles are the ends of "C"-shaped magnets. In each row, adjacent poles are separated by spacers made of a superconducting material.
Tatchyn, R.O.; Csonka, P.L.; Cremer, J.T.
1990-12-11
Micropole undulators for use in the generation of x-rays from moving charged particles are disclosed. Two rows of spaced apart poles are arranged so that each pole produces a magnetic field aligned with all other similar fields. The poles are the ends of C''-shaped magnets. In each row, adjacent poles are separated by spacers made of a superconducting material. 11 figs.
Plettner, T; Byer, R.L.; /Stanford U., Ginzton Lab.
2011-09-16
This article presents the concept of an all-dielectric laser-driven undulator for the generation of coherent X-rays. The proposed laser-driven undulator is expected to produce internal deflection forces equivalent to a several-Tesla magnetic field acting on a speed-of-light particle. The key idea for this laser-driven undulator is its ability to provide phase synchronicity between the deflection force and the electron beam for a distance that is much greater than the laser wavelength. The potential advantage of this undulator is illustrated with a possible design example that assumes a small laser accelerator which delivers a 2 GeV, 1 pC, 1 kHz electron bunch train to a 10 cm long, 1/2 mm period laser-driven undulator. Such an undulator could produce coherent X-ray pulses with {approx}10{sup 9} photons of 64 keV energy. The numerical modeling for the expected X-ray pulse shape was performed with GENESIS, which predicts X-ray pulse durations in the few-attosecond range. Possible applications for nonlinear electromagnetic effects from these X-ray pulses are briefly discussed.
Recent Progress in the Theory of the Crystalline Undulator
Kostyuk, Andriy
2013-01-01
If an ultrarelativistic charged particle channels inside a single crystal with periodically bent crystallographic planes, it emits hard electromagnetic radiation of the undulator type. Due to similarity of its physical principles to the ordinary (magnetic) undulator, such a device is termed as the crystalline undulator. Recent development of a new Monte Carlo code ChaS made possible a detailed simulation of particle channeling and radiation emission in periodically bent crystals. According to recent findings, energy of the electron beam below 1 GeV is sufficient to observe the undulator effect in a periodically bent crystal. Even more exciting results were obtained for a crystalline undulator whose bending period is shorter than the period of the channeling oscillations and the bending amplitude is smaller than the width of the planar channel. Such a crystalline undulator is far superior to what was proposed previously. It allows for a large effective number of undulator periods. Therefore, it is predicted to...
Transmission Grating Measurements of Undulator K
Bionta, R. M.
2010-12-01
This study was undertaken to understand the practicalities of determine K differences in the undulator modules by measuring single-shot x-ray spectra of the spontaneous radiation with a transmissive grating spectrometer under development to measure FEL spectra. Since the quality of the FEL is dependent on a uniform K value in all the undulator modules, being able to measure the relative undulator K values is important. Preliminary results were presented in a presentation, 'Use of FEL Off-Axis Zone Plate Spectrometer to Measure Relative K by the Pinhole/Centroid Method', at the 'LCLS Beam-Based Undulator K Measurements Workshop' on November 14, 2005 (UCRL-PRES-217281). This study applies equally well to reflective gratings of the appropriate period and inclinations.
Self-Stimulated Undulator Klystron
Bessonov, E G; Mikhailichenko, A A
2011-01-01
The Self Stimulated Undulator Klystron (SSUK) and its possible applications in the Particle Accelerator Physics, incoherent Self-Stimulated Undulator Radiation Sources (SSUR) and Free-Electron Lasers (FEL) are discussed.
The Properties of Undulator Radiation
Howells, M.R.
2011-01-01
Experiments with an Optical Klystron Installed on the VEPP-3the transverse optical klystron undulator at Brookhaven, BL
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-InspiredAtmosphericdevicesPPO Retirees withEnergy Special Effects59 Federal5
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-InspiredAtmosphericdevicesPPO Retirees withEnergy Special Effects59
Use of Dynamical Undulator Mechanism to Produce Short Wavelength Radiation in Volume FEL (VFEL)
V. G. Baryshevsky; K. G. Batrakov
2002-09-06
VFEL lasing in system with dynamical undulator is described. In this system radiation of long wavelength creates the undulator for lasing on shorter wavelength. Two diffraction gratings with different spatial periods form VFEL resonator. The grating with longer period pumps the resonator with long wavelength radiation to provide necessary amplitude of undulator field. The grating with shorter period makes mode selection for short wavelength radiation. Lasing of such a system in terahertz frequency range is discussed.
Flying radio frequency undulator
Kuzikov, S. V.; Vikharev, A. A. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)
2014-07-21
A concept for the room-temperature rf undulator, designed to produce coherent X-ray radiation by means of a relatively low-energy electron beam and pulsed mm-wavelength radiation, is proposed. The “flying” undulator is a high-power short rf pulse co-propagating together with a relativistic electron bunch in a helically corrugated waveguide. The electrons wiggle in the rf field of the ?1st spatial harmonic with the phase velocity directed in the opposite direction in respect to the bunch velocity, so that particles can irradiate high-frequency Compton's photons. A high group velocity (close to the speed of light) ensures long cooperative motion of the particles and the co-propagating rf pulse.
Soft x-ray undulator for the Siam Photon Source
Rugmai, S.; Dasri, T.; Prawanta, S.; Siriwattanapaitoon, S.; Kwankasem, A.; Sooksrimuang, V.; Chachai, W.; Suradet, N.; Juthong, N.; Tancharakorn, S.
2007-01-19
An undulator for production of intense soft x-rays has been designed for the Siam Photon Source. The construction of the undulator has been completed. It is now being characterized and prepared for installation. The device, named U60, is a pure permanent magnet planar undulator, consisting of 41 magnetic periods, with 60 mm period length. Utilization of the undulator radiation in the photon energy range of 30 - 900 eV is expected. The design studies of the magnetic structure, including investigation of perturbations arising from the magnetic field of the device, their effects on the SPS storage ring and compensation schemes are described. A magnetic measurement system has been constructed for magnetic characterization of the device. Partial results of magnetic measurements are presented.
Performance Evaluation of Undulator Radiation at CEBAF
Chuyu Liu, Geoffrey Krafft, Guimei Wang
2010-05-01
The performance of undulator radiation (UR) at CEBAF with a 3.5 m helical undulator is evaluated and compared with APS undulator-A radiation in terms of brilliance, peak brilliance, spectral flux, flux density and intensity distribution.
An Undulator Based Polarized Positron Source for CLIC
Liu, Wanming; /Argonne; Gai, Wei; /Argonne; Rinolfi, Louis; /CERN; Sheppard, John; /SLAC
2012-07-02
A viable positron source scheme is proposed that uses circularly polarized gamma rays generated from the main 250 GeV electron beam. The beam passes through a helical superconducting undulator with a magnetic field of {approx} 1 Tesla and a period of 1.15 cm. The gamma-rays produced in the undulator in the energy range between {approx} 3 MeV - 100 MeV will be directed to a titanium target and produce polarized positrons. The positrons are then captured, accelerated and transported to a Pre-Damping Ring (PDR). Detailed parameter studies of this scheme including positron yield, and undulator parameter dependence are presented. Effects on the 250 GeV CLIC main beam, including emittance growth and energy loss from the beam passing through the undulator are also discussed.
Conceptual Design for Superconducting Planar Helical Undulator
Sasaki, Shigemi
2004-05-12
A preliminary consideration was made on a short-period superconducting planar helical undulator (SCHU) for circularly polarized radiation. The SCHU consists of coils and iron poles/yokes. There is no magnetic structure in the horizontal plane of the electron orbit. The SCHU would provide the large horizontal aperture needed to allow injection into the storage ring. The expected field strength is at least 30% larger than that by an APPLE-type permanent-magnet device with the same gap and the same period.
Undulator-Based Production of Polarized Photons
Professor Kirk McDonald
2008-05-29
"Project Title: Undulator-Based Production of Polarized Photons" DOE Contract Number: FG02-04ER41355 Principal Investigator: Prof. Kirk McDonald Period of Performance: 09/10/2004 thru 08/31/2006 This award was to fund Princeton's activity on SLAC experiment E166, "Undulator-Based Production of Polarized Positrons" which was performed at SLAC during June and September 2005. Princeton U. fabricated a magnetic spectrometer for this experiment, and participated in the commissioning, operation, and analysis of the experiment, for which Prof. McDonald was a co-spokesperson. The experiment demonstrated that an intense positron beam with 80% longitudinal polarization could be generated by conversion of MeVenergy circularly polarized photons in a thin target, which photons were generated by passage of high-energy electrons through a helical undulator. This technique has since been adopted as the baseline for the polarized positron source of the proposed International Linear Collider. Results of the experiment have been published in Physical Review Letters, vol 100, p 210801 (2008) [see attached .pdf file], and a longer paper is in preparation.
Photon emission by ultra-relativistic positrons in crystalline undulators: the high-energy regime
Krause, W; Solov'yov, A V; Greiner, W
2015-01-01
This paper discusses the undulator radiation emitted by high-energy positrons during planar channeling in periodically bent crystals. We demonstrate that the construction of the undulator for positrons with energies of 10 GeV and above is only possible if one takes into account the radiative energy losses. The frequency of the undulator radiation depends on the energy of the particle. Thus the decrease of the particle's energy during the passage of the crystal should result in the destruction of the undulator radiation regime. However, we demonstrate that it is possible to avoid the destructive influence of the radiative losses on the frequency of the undulator radiation by the appropriate variation of the shape of the crystal channels. We also discuss a method by which, to our mind, it would be possible to prepare the crystal with the desired properties of its channels.
The U5. 0 Undulator for the ALS
Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.
1991-05-01
The U5.0 Undulator, an 89 period, 5 cm period length, 4.6 m long insertion device has been designed and is in fabrication. This undulator will be the first high brightness source, in the 50 to 1500 eV range, for the Advanced Light Source (ALS) and is scheduled for completion in 1992. A modular hybrid configuration utilizing Nd-Fe-B permanent magnet material and vanadium permendur is used that achieves 0.837 Tesla effective peak field. Correction of the vertical field integral is with permanent magnet rotors at the ends. Gap adjustment is with an arrangement of roller screws, chains drives, a gear reduction unit and a stepper motor driven by a closed loop control system. The vacuum chamber design is a two-piece, machined and welded 5083-H321 aluminum construction of 5.1 m length. Magnetic design, subsystem design and fabrication progress are presented. 12 refs., 4 figs., 2 tabs.
Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics
Jeff, A; Welsch, CP
2013-01-01
The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMA...
Fast pulsed excitation wiggler or undulator
van Steenbergen, Arie (Shoreham, NY)
1990-01-01
A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.
Positioning system for the LCLS undulator.
Trakhenberg, E. M.
2002-09-12
The Linac Coherent Light Source (LCLS) Project includes the undulator subsystem that has 33 undulator magnetic structures each 3.4 m long. Positioning of the LCLS undulators along the undulator line with an accuracy of 50 {micro}m in the vertical transverse direction is required. A prototype of the LCLS undulator has been built with a positioning system based on three stages with cam shafts. Each cam shaft produces reciprocating motion with a range of {+-}3 mm. A servomotor with integrated brake, incremental rotary encoder, servo amplifier, and controller is used with a 100:1 ratio gear box to drive each cam shaft. Resolution of the motion control is about 0.05 {micro}m. SmartMotors are connected in parallel through an RS-485 interface to the serial port of the computer. With this approach, the control system is easily expandable; up to 120 motors can be controlled with one serial port. Positioning accuracy of about 10 {micro}m for the LCLS undulator prototype is demonstrated.
Method of Linear Invariants for description of beam dynamics of FEL undulator
A. Angelow; D. Trifonov; V. Angelov; H. Hristov
2008-05-23
We propose a new model for description of electrons beam dynamics in Free Electron Laser (FEL) undulator, based on the method of linear time-dependent invariants of quantum-mechanical charge particle. The magnetic field has periodic structure along the undulator. For this problem, described by time-dependent quadratic Hamiltonian, we obtain exact solution. The time-evolutions of the tree quantum fluctuations: covariance cov(q,p), var(q) and var(p) for the charge particle in this case are also determined. This research will help to optimize the FEL undulator: for example, using a 2.5 GeV linear electron accelerator it will be possible to emit radiation at 1.5 nm and shorter length. This method could be applicable also to any device with periodic structure of applied field (e.g. Tokamak, cyclic accelerators) for the case of charge non-relativistic quantum particles.
Undulator Hall Air Temperature Fault Scenarios
Sevilla, J.; Welch, J.; ,
2010-11-17
Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about {+-}2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.
Coherent Radiation Effects in the LCLS Undulator
Reiche, S.; /UCLA; Huang, Z.; /SLAC
2010-12-14
For X-ray Free-Electron Lasers such as LCLS and TESLA FEL, a change in the electron energy while amplifying the FEL radiation can shift the resonance condition out of the bandwidth of the FEL. The largest sources of energy loss is the emission of incoherent undulator radiation. Because the loss per electron depends only on the undulator parameters and the beam energy, which are fixed for a given resonant wavelength, the average energy loss can be compensated for by a fixed taper of the undulator. Coherent radiation has a strong enhancement proportional to the number of electrons in the bunch for frequencies comparable to or longer than the bunch dimension. If the emitted coherent energy becomes comparable to that of the incoherent emission, it has to be included in the taper as well. However, the coherent loss depends on the bunch charge and the applied compression scheme and a change of these parameters would require a change of the taper. This imposes a limitation on the practical operation of Free-Electron Lasers, where the taper can only be adjusted manually. In this presentation we analyze the coherent emission of undulator radiation and transition undulator radiation for LCLS, and estimate whether the resulting energy losses are significant for the operation of LCLS.
Optical Fibre Dosimeter for SASE FEL Undulators
Körfer, M
2003-01-01
Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is ...
Planar Undulator Considerations(LCC-0085)
Sheppard, J
2003-10-07
This note consists of informal working notes that document an effort to understand the TESLA baseline, unpolarized, undulator based positron source. This is the first step in the design process of an undulator based positron system for the NLC. The expressions and methodologies developed herein are used in subsequent memos that reference this note. In regards to the TESLA design, it is found that a 135 m long (versus 100 m length) undulator is consistent with the performance descriptions in the TDR text. And while operation of the TESLA system with a 250 GeV drive beam energy provides a safety margin of a factor of {approx}2 in e{sup +} yield, operation of the same system at 160 GeV results in a yield of about 0.6.
Strong permanent magnet-assisted electromagnetic undulator
Halbach, Klaus (Berkeley, CA)
1988-01-01
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.
Undulator Radiation Damage Experience at LCLS
Nuhn, H. D.; Field, C.; Mao, S.; Levashov, Y.; Santana, M.; Welch, J. N.; Wolf, Z.
2015-01-06
The SLAC National Accelerator Laboratory has been running the Linac Coherent Light Source (LCLS), the first x-ray Free Electron Laser since 2009. Undulator magnet damage from radiation, produced by the electron beam traveling through the 133-m long straight vacuum tube, has been and is a concern. A damage measurement experiment has been performed in 2007 in order to obtain dose versus damage calibrations. Radiation reduction and detection devices have been integrated into the LCLS undulator system. The accumulated radiation dose rate was continuously monitored and recorded. In addition, undulator segments have been routinely removed from the beamline to be checked for magnetic (50 ppm, rms) and mechanic (about 0.25 µm, rms) changes. A reduction in strength of the undulator segments is being observed, at a level, which is now clearly above the noise. Recently, potential sources for the observed integrated radiation levels have been investigated. The paper discusses the results of these investigation as well as comparison between observed damage and measured dose accumulations and discusses, briefly, strategies for the new LCLS-II upgrade, which will be operating at more than 300 times larger beam rate.
MEMS multi-pole electromagnets: Compact electron optics and undulators
Harrison, Jere Charles
2014-01-01
laser system using MEMS optics . . . . . . . . . Heatattempt at MEMS undulators and focusing optics. . . . . .all published quadrupole optics by more than an order of
UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC
Bakeman, M.S.
2010-01-01
ACCELERATOR ELECTRON BEAM DIAGNOSTIC* M.S. Bakeman # , W.M.of an undulator-based electron beam diagnostic to be used in
Tapering studies for Terawatt level X-ray FELs with a superconducting undulator
Emma, Claudio; Emma, Paul; Huang, Zhirong; Pellegrini, Claudio
2015-01-01
We study the tapering optimization scheme for a short period, less than two cm, superconducting undulator, and show that it can generate 4 keV X-ray pulses with peak power in excess of 1 terawatt, using LCLS electron beam parameters. We study the e?ect of undulator module length relative to the FEL gain length for continous and step-wise taper pro?les. For the optimal section length of 1.5m we study the evolution of the FEL process for two di?erent superconducting technologies NbTi and Nb3Sn. We discuss the major factors limiting the maximum output power, particle detrapping around the saturation location and time dependent detrapping due to generation and ampli?cation of sideband modes.
Anania, M. P. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); INFN, Laboratori Nazionali di Frascati, I-00044 Frascati (Italy); Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A., E-mail: d.a.jaroszynski@strath.ac.uk [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Geer, S. B. van der; Loos, M. J. de [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands); Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A. [ASTeC, STFC, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Gillespie, W. A. [SUPA, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); MacLeod, A. M. [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee DD1 1HG (United Kingdom)
2014-06-30
Narrow band undulator radiation tuneable over the wavelength range of 150–260?nm has been produced by short electron bunches from a 2?mm long laser plasma wakefield accelerator based on a 20?TW femtosecond laser system. The number of photons measured is up to 9?×?10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1?×?10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130?MeV with the radiation pulse duration in the range of 50–100 fs.
The equivalence of inverse Compton scattering and the undulator concept
Ng, K.Y,; /Fermilab
2009-08-01
Inverse Compton scattering is a method to produce very high frequency photon beam. However, the production mechanism can also be viewed as a undulator emission. This is because the electron sees electric and magnetic fields of the incident laser beam and is driven into transverse oscillatory motion in exactly the same way when the electron passes through a undulator consisting of alternating magnetic field. This note gives a detailed examination of the similarity about the two views. Equivalent undulator parameters are derived for the incident laser beam, as well as the differential cross section of photon emission.
A Fixed Gap APPLE II Undulator for SLS
Schmidt, T.; Imhof, A.; Ingold, G.; Jakob, B.; Vollenweider, C.
2007-01-19
To vary the polarization vector of an APPLE II undulator continuously from 0 - 180 deg., all four magnet arrays need to be movable. Following the adjustable-phase undulator approach by R. Carr, a 3.4 m long fixed gap undulator for SLS with a gap of 11.6 mm has been constructed. It will be installed in fall 2006. The gap drive is replaced by a pair-wise shift of the magnet arrays to change the energy, while the polarization is changed by shifts of diagonal arrays. The high injection efficiency and standard operation top-up mode at the SLS allows this simplified undulator design. The design as well as the operational aspects will be discussed.
Modeling performance of horizontal, undulating, and multilateral wells
Kamkom, Rungtip
2009-05-15
Horizontal, undulating, and multilateral wells are relatively new alternatives in field development because they can increase the productivity per well and reduce the cost of field development. Because the feasibility of these wells may not be valid...
Virginia Tech
Heat Transfer - 1 Consider a composite pipe of inner diameter 10 cm and outer diameter 10.6 cm subjected to an external constant uniform heat flux of 100,000 W/m2 . The composite material of the pipe has/mK in the axial direction. Both ends of the pipe are insulated from any heat loss. The pipe is cooled by water
Solomon, L.
1998-05-01
Measurements of the multipole content of the Mini-Undulator magnet have been made with two different integrating wire techniques. Both measurements used 43 strand Litz wire stretched along the length of the magnet within the magnet gap. In the first technique, the wire motion was purely translational, while in the second technique the wire was moved along a circular path. The induced voltage in the Litz wire was input into a Walker integrator, and the integrator output was analyzed as a function of wire position for determination of the multipole content of the magnetic field. The mini-undulator magnet is a 10 period, 80 mm per period hybrid insertion device. For all the data contained herein the magnet gap was set at 49 mm. In the mini-undulator magnet, the iron poles are 18mm x 32mm x 86 mm, and the Samarium Cobalt permanent magnet blocks are 22mm x 21mm x 110mm. For this magnet, which is a shortened prototype for the NSLS Soft X-Ray Undulator Magnet, the undulator parameter K = 0.934 B (Tesla){lambda}(cm), and B(tesla) = 0.534/sinh({pi}Gap/{lambda}). At a gap of 49 mm, the magnetic field is 1590 Gauss.
Solomon, L.; Ingold, G.; Ben-Zvi, I.; Krinsky, S.; Yu, L.H.; Sampson, W.; Robins, K.
1993-07-01
An 18mm period, 0.54 Tesla, 8mm gap superconducting undulator with both horizontal and vertical focusing has been built and tested. This magnet, which is fabricated in 25 cm length sections, is being tested for use in the radiator section (total magnet length of 1.5 m) of the Harmonic Generation Free Electron Laser experiment at the National Synchrotron Light Source - Accelerator Test Facility at Brookhaven National Lab., in collaboration with Grumman Corp. The measurement system is outlined, sources and estimates of errors are described, and some magnetic field data are presented and discussed.
Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic
Bakeman, M.S.
2011-01-01
Accelerator, Undulator, Electron Beam Diagnostic PACS: 52 .of an undulator-based electron beam diagnostic to be used inElectron Beam Energy Spread and Emittance Diagnostic M.S.
Undulators for the BESSY SASE-FEL Project
Bahrdt, J.; Frentrup, W.; Gaupp, A.; Kuske, B.; Meseck, A.; Scheer, M.
2004-05-12
BESSY plans to build a SASE-FEL facility for the energy range from 20 eV to 1000 eV. The energy range will be covered by three APPLE II type undulators with a magnetic length of about 60 m each. This paper summarizes the basic parameters of the FEL-undulators. The magnetic design will be presented. A modified APPLE II design will be discussed which provides higher fields at the expense of reduced horizontal access. GENESIS simulations give an estimate on the tolerances for the beam wander and for gap errors.
A strong permanent magnet-assisted electromagnetic undulator
Halbach, K.
1987-01-30
This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.
Proposed dielectric-based microstructure laser-driven undulator T. Plettner and R. L. Byer
Byer, Robert L.
sources that feed into permanent-magnet undulators. The distinguish- ing feature of the undulator proposed a proposed all-dielectric laser-driven undulator for the generation of coherent short wavelengths and explore-electron radiation concepts for ultrashort coherent wavelength generation are being investigated. For example, active
Triggering for Magnetic Field Measurements of the LCLS Undulators
Hacker, Kirsten
2010-12-13
A triggering system for magnetic field measurements of the LCLS undulators has been built with a National Instruments PXI-1002 and a Xylinx FPGA board. The system generates single triggers at specified positions, regardless of encoder sensor jitter about a linear scale.
Elias, N; Dalexandro, N; Giloux, C; Bordini, B; Maccaferri, R
2010-01-01
The future run of the Large Hadron Collider with lead ions will require important modifications in the synchrotron radiation profile monitor system, which at present comprises two superconducting undulators wound from Nb-Ti conductor, delivering 5 T in a 60 mm gap, and with a period of 280 mm. Whilst the gap and the nominal field of the future undulators will remain the same, the period shall be 140 mm, which translates to a peak field of over 8 T in the coils and hence requires the use of Nb3Sn technology. In this paper the electromagnetic design of the undulator is summarized. We describe the fabrication of a race-track coil wound with a 0.8 mm diameter Nb3Sn strand with ceramic insulation. Finally, the results of successful tests made at 4.3 K and 1.9 K in a mirror configuration are presented. 10 T at 4.3 K and 11.5 T at 1.9 K were measured in the yoke gap, thus validating this concept for the future undulator.
Investigation of a 2-Colour Undulator FEL Using Puffin
Campbell, L T; Reiche, S
2013-01-01
Initial studies of a 2-colour FEL amplifier using one monoenergetic electron beam are presented. The interaction is modelled using the unaveraged, broadband FEL code Puffin. A series of undulator modules are tuned to generate two resonant frequencies along the FEL interaction and a self-consistent 2-colour FEL interaction at widely spaced non-harmonic wavelengths at 1nm and 2.4nm is demonstrated.
Undulator radiation simulation tools in view of proton beam diagnostics in LHC
Ponce, L; CERN. Geneva. SPS and LHC Division
2001-01-01
As a superconducting undulator is planned to be used for beam diagnostics in LHC, it appeared to be necessary to adapt the simulation tools. Hence, a new procedure UNDULATOR has been implemented in the ray-tracing code Zgoubi and is assessed in this paper. After a brief recall of the numerical methods of concern, some simulations with UNDULATOR are compared, first with classical analytical models and then with field map based methods using the procedure TOSCA.
Production of Ultrashort FEL XUV Pulses via a Reverse Undulator Taper
Fawley, William M.
2007-01-01
Production of Ultrashort FEL XUV Pulses via a Reverseof 2009. In recent years, FEL researchers have explored ara- diator undulators, the FEL emission will predomi- nately
Preparing the BESSY APPLE Undulators for Top-Up Operation
Bahrdt, J.; Frentrup, W.; Gaupp, A.; Scheer, M.
2007-01-19
BESSY plans to go to topping up operation in the near future. A high injection efficiency is essential to avoid particle losses inside the undulator magnets and to ensure a low radiation background in the beamlines. Dynamic and static multipoles of the insertion devices have to be minimized to accomplish this requirement. APPLE II devices show strong dynamic multipoles in the elliptical and vertical polarization mode. Measurements before and after shimming of these multipoles are presented. The static multipoles of the BESSY UE56-2 which are due to systematic block inhomgeneities have successfully been shimmed recovering the full dynamic aperture.
Radiological Considerations in the Operation of the Low-Energy Undulator Test Line (LEUTL)
Kemner, Ken
1 Radiological Considerations in the Operation of the Low-Energy Undulator Test Line (LEUTL) April 10, 1998 H. J. Moe 1. General The Low-Energy Undulator Test Line (LEUTL) is a facility that uses dump. This facility is about 51 m long and 3.66 m wide. Technical compo- nents and diagnostics
Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields
Reiche, S; Emma, P; Fawley, W M; Huang, Z; Nuhn, H D; Stupakov, G V
2005-01-01
Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields
Bane, K L F; Tu, J J
2006-01-01
Reflectivity Measurements for Copper and Aluminumin the Far Infrared and the Resistive Wall Impedance in the LCLS Undulator
Roper, Mark D.; Bird, Daniel T.
2004-05-12
The soft x-ray beamline 5U1 on the Daresbury Laboratory SRS currently uses a planar undulator, producing linearly polarized radiation in the range 100 to 1000 eV. The undulator is soon to be replaced by a variable-polarization device of the Apple II design. The aim is to produce circularly polarized light in the energy range 265 to 1000 eV, covering the K-edges of C, N and O, and the first row transition element L-edges. This will greatly enhance the provision of circularly polarized soft-x-rays on the SRS and open up new opportunities for experimenters. The device will also produce linear polarization with a selectable angle of polarization with respect to the orbit plane, which is currently unavailable on the SRS. In order to provide the coverage over this energy range, we are exploiting the relatively large emittance of the SRS to allow us to use the second and third harmonics even in circular polarization mode. This paper presents the expected beamline output in various polarization modes and the predicted degree of polarization.
Gap solitons in rocking optical lattices and waveguides with undulating gratings
Mayteevarunyoo, Thawatchai; Malomed, Boris A.
2009-07-15
We report results of a systematic analysis of the stability of one-dimensional solitons in a model including the self-repulsive or attractive cubic nonlinearity and a linear potential represented by a periodically shaking lattice, which was recently implemented in experiments with Bose-Einstein condensates. In optics, the same model applies to undulated waveguiding arrays, which are also available to the experiment. In the case of the repulsive nonlinearity, stability regions are presented, in relevant parameter planes, for fundamental gap solitons and their two-peak and three-peak bound complexes, in the first and second finite band gaps. In the model with the attractive nonlinearity, stability regions are produced for fundamental solitons and their bound states populating the semi-infinite gap. In the first finite and semi-infinite gaps, unstable solitons gradually decay into radiation, while, in the second finite band gap, they are transformed into more complex states, which may represent new species of solitons. For a large amplitude of the rocking-lattice drive, the model is tantamount to that with a 'flashing' lattice potential, which is controlled by periodic sequences of instantaneous kicks. Using this correspondence, we explain generic features of the stability diagrams for the solitons. We also derive a limit case of the latter system, in the form of coupled-mode equations with a 'flashing' linear coupling.
A possibility for using an APPLE undulator to generate a photon beam with transverse optical modes.
Sasaki, S.; McNulty, I.; Shimada, T.; JAEA
2008-01-01
We investigate use of an APPLE-type undulator for generating Laguerre-Gaussian (LG) and Hermite-Gaussian (HG) mode beams. We find that the second harmonic radiation in the circular mode corresponds to an LG beam with l=1, and the second harmonic in the linear mode corresponds to an HG beam with l=1. The combination of an APPLE undulator and conventional monochromator optics may provide an opportunity for a new type of experimental research in the synchrotron radiation community.
SOLOMON, L.
1998-05-01
Measurements of the multipole content of the Mini-Undulator magnet have been made with two different integrating wire techniques. Both measurements used 43 strand Litz wire stretched along the length of the magnet within the magnet gap. In the first technique, the wire motion was purely translational, while in the second technique the wire was moved along a circular path. The induced voltage in the Litz wire was input into a Walker integrator, and the integrator output was analyzed as a function of wire position for determination of the multipole content of the magnetic field. The mini-undulator magnet is a 10 period, 80 mm per period hybrid insertion device. For all the data contained herein the magnet gap was set at 49 mm. In the mini-undulator magnet, the iron poles are 18mm x 32mm x 86mm, and the Samarium Cobalt permanent magnet blocks are 22mm x 21mm x 110mm. For this magnet, which is a shortened prototype for the NSLS Soft X-Ray Undulator Magnet, the undulator parameter K = 0.934 B(Tesla){lambda}(cm), and B(tesla) = 0.534/sinh({pi}Gap/{lambda}). At a gap of 49 mm, the magnetic field is 1590 Gauss. The 43 strand Litz wire is supported on motorized x-y stages at both ends of the magnet, which are controlled by stepping motors through a Labview program. One leg of the wire loop is within the magnet gap, and the other leg is in an essentially field free region. Only the leg of the wire loop within the magnet gap is moved during data acquisition. The Litz wire is tensioned with 11.5 pounds, and is wrapped with a supporting tape which is itself tensioned with 18 pounds through a spring and turnbuckle arrangement. With this setup the sag in the wire over the 72 inch span is less than 0.003 inches, as measured with survey instruments. Photographs of the setup are shown.
Fabrication of a Short-Period Nb3Sn Superconducting Undulator
Dietderich, Daniel
2008-01-01
Trans. on Applied Superconductivity, Vol. 13, No. 2, pp.Trans. on Applied Superconductivity, MT-19, June 2005. [7]Trans. on Applied Superconductivity, vol. 15, no. 2, 2005,
Undulation Amplitude of a Fluid Membrane Surrounded by Near-Critical Binary Fluid Mixtures
Youhei Fujitani
2015-10-10
We consider the thermal undulation, or shape fluctuation, of an almost planar fluid membrane surrounded by the same near-critical binary fluid mixtures on both sides. A weak preferential attraction is assumed between the membrane and one component of the mixture. We use the Gaussian free-energy functional to study the equilibrium average of the undulation amplitude within the linear approximation with respect to the amplitude. According to our result given by a simple analytic formula, the ambient near-criticality tends to suppress the undulation of a membrane, and this suppression effect can overwhelm that of the bending rigidity for small wave numbers. Thus, the ambient near-criticality is suggested to prevent a large membrane from becoming floppy even if the lateral tension vanishes at the equilibrium.
Undulation Amplitude of a Fluid Membrane Surrounded by Near-Critical Binary Fluid Mixtures
Youhei Fujitani
2014-12-22
We consider the thermal undulation, or shape fluctuation, of an almost planar fluid membrane surrounded by the same near-critical binary fluid mixtures on both sides. A weak preferential attraction is assumed between the membrane and one component of the mixture. We use the Gaussian free-energy functional to study the equilibrium average of the undulation amplitude within the linear approximation with respect to the amplitude. According to our result given by a simple analytic formula, the ambient near-criticality tends to suppress the undulation of a membrane without the lateral tension. This suppression effect can overwhelm that of the bending rigidity for small wave numbers. Thus, the ambient near-criticality can prevent a large membrane from becoming floppy even if it has no lateral tension.
Cyclotron-undulator cooling of a free-electron-laser beam
Bandurkin, I. V.; Kuzikov, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)
2014-08-18
We propose methods of fast cooling of an electron beam, which are based on wiggling of particles in an undulator in the presence of an axial magnetic field. We use a strong dependence of the axial electron velocity on the oscillatory velocity, when the electron cyclotron frequency is close to the frequency of electron wiggling in the undulator field. The abnormal character of this dependence (when the oscillatory velocity increases with the increase of the input axial velocity) can be a basis of various methods for fast cooling of moderately relativistic (several MeV) electron beams.
Knot undulator to generate linearly polarized photons with low on-axis power density
Qiao, S; Feng, Donglai; Hussain, Z; Shen, Z -X
2008-01-01
Heat load on beamline optics is a serious problem to generate pure linearly polarized photons in the third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by a figure-8 operating mode. But there is still no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel operating mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Also the available minimum photon energy of linearly polarized photons can be extended much by this method.
Polarization Analysis for Seeded FELs in a Crossed-Planar Undulator
Geng, Huiping; /SLAC; Ding, Yuantao; /SLAC; Huang, Zhirong; /SLAC; Bartolini, Riccardo; /Diamond Light Source; Dunning, David; /Daresbury; Thompson, Neil; /Daresbury
2012-06-25
The crossed-planar undulator is a promising scheme for full polarization control in x-ray FELs. For SASE FELs, it has been shown a maximum degree of circular polarization of about 80% is achievable at fundamental wavelength just before saturation. In this paper, we study the effectiveness of a crossed undulator for a seeded x-ray FEL. The degree of circular polarization for both the fundamental and the harmonic radiation are considered. Simulations with realistic beam distributions show that a degree of circular polarization of over 90% and 80% is obtainable at the fundamental and 2nd harmonic frequencies, respectively.
MEMS multi-pole electromagnets: Compact electron optics and undulators
Harrison, Jere Charles
2014-01-01
electron laser system using MEMS optics . . . . . . . . .power soft x-ray source based on a 400-µm period MEMS un-micrograph of a MEMS ‘racetrack’ transformer. . . . . . .
INTRODUCTION Locomotion using undulating dorsal or anal fins is a mode of fish
Curet, Oscar M.
823 INTRODUCTION Locomotion using undulating dorsal or anal fins is a mode of fish swimming that has evolved independently in a number of unrelated teleost fish clades. Fishes swimming in this manner (Gymnarchus niloticus), the bowfin (Amia calva), and several deep- sea fishes such as the oarfish (Regalecus
Roughness Tolerance Studies for the Undulator Beam Pipe Chamber of LCLS-II
Bane, K
2014-01-01
We investigate the effect of wall roughness on the wakefield-induced energy variation in the undulator beam pipe of LCLS-II. We find that a wall roughness equivalent to an rms surface slope of 30 mr increases the total induced energy variation within the bunch (due to the resistive wall wake) by a modest 20%.
Manufacturing Considerations of the Magnetic Structures for the Undulators for the X-FEL at TESLA
1 Manufacturing Considerations of the Magnetic Structures for the Undulators for the X-FEL at TESLA DESY / HASYLAB Notkestr. 85, 22607 Hamburg, Germany TESLA-FEL 2000-10 Abstract A study is presented FELs. The total magnetic length of the magnet structures is 1405m. It is proposed to produce these huge
Field Accuracy Requirements for the Undulator Systems of the X-ray FEL's at TESLA
Field Accuracy Requirements for the Undulator Systems of the X-ray FEL's at TESLA B. Faatz, J. 85, 22607 Hamburg, Germany Abstract In SASE FELs, the radiation power has to saturate in a single. The influence of the electron beam quality has been studied in detail in many papers. For the TESLA X-ray FEL
Energy Loss and Energy Spread Growth in a Planar Undulator(LCC-0086)
Sheppard, J
2003-10-07
The change in beam energy spread due to transmission through a long, planar undulator is calculated. This change is shown to be gaussian as expected from the central limit theorem and large number of photons emitted per electron. These results are compared with Saldin et al. [2] expressions. Numerical results for the case of the TESLA beam and for an NLC beam are given.
Radiation from multi-GeV electrons and positrons in periodically bent silicon crystal
Bezchastnov, Victor G; Solovyov, Andrey V
2015-01-01
A periodically bent Si crystal is shown to efficiently serve for producing highly monochromatic radiation in a gamma-ray energy spectral range. A short-period small-amplitude bending yields narrow undulator-type spectral peaks in radiation from multi-GeV electrons and positrons channeling through the crystal. Benchmark theoretical results on the undulator are obtained by simulations of the channeling with a full atomistic approach to the projectile-crystal interactions over the macroscopic propagation distances. The simulations are facilitated by employing the MBN Explorer package for molecular dynamics calculations on the meso- bio- and nano-scales. The radiation from the ultra-relativistic channeling projectiles is computed within the quasi-classical formalism. The effects due to the quantum recoil are shown to be significantly prominent in the gamma-ray undulator radiation.
Steiner, J.L.; Siebe, D.A.; Boyack, B.E.
1987-01-01
Los Alamos National Laboratory is a participant in the Integral System Test (IST) program initiated in June 1983 for the purpose of providing integral system test data on specific issues/phenomena relevant to post-small-break loss-of-coolant accidents (SBLOCAs), loss of feedwater and other transients in Babcock and Wilcox (B and W) plant designs. The Multi-Loop Integral System Test (MIST) facility is the largest single component in the IST program. MIST is a 2 x 4 (2 hot legs and steam generators, 4 cold legs and reactor-coolant pumps) representation of lowered-loop reactor systems of the B and W design. It is a full-height, full-pressure facility with 1/817 power and volume scaling. Two other experimental facilities are included in the IST program: test loops at the University of Maryland, College Park, and at Stanford Research Institute. The objective of the IST tests is to generate high-quality experimental data to be used for assessing thermal-hydraulic safety computer codes. Efforts are underway at Los Alamos to assess TRAC-PF1/MOD1 against data from each of the IST facilities. Calculations and data comparisons for TRAC-PF1/MOD1 assessment have been completed for two transients run in the MIST facility. These are the MIST nominal test. Test 3109AA, a scaled 10 cm/sup 2/ SBLOCA and Test 320201, a scaled 50 cm/sup 2/ SBLOCA. Only MIST assessment results are presented in this paper.
Canted Undulator Upgrade for GeoSoilEnviroCARS Sector 13 at the Advanced Photon Source
Sutton, Stephen
2013-02-02
Support for the beamline component of the canted undulator upgrade of Sector 13 (GeoSoilEnviroCARS; managed and operated by the University of Chicago) at the Advanced Photon Source (APS; Argonne National Laboratory) was received from three agencies (equally divided): NASA-SRLIDAP (now LARS), NSF-EAR-IF (ARRA) and DOE-Single Investigator Small Group (SISGR). The associated accelerator components (undulators, canted front end) were provided by the APS using DOE-ARRA funding. The intellectual merit of the research enabled by the upgrade lies in advancing our knowledge of the composition, structure and properties of earth materials; the processes they control; and the processes that produce them. The upgrade will facilitate scientific advances in the following areas: high pressure mineral physics and chemistry, non-crystalline and nano-crystalline materials at high pressure, chemistry of hydrothermal fluids, reactions at mineral-water interfaces, biogeochemistry, oxidation states of magmas, flow dynamics of fluids and solids, and cosmochemistry. The upgrade, allowing the microprobe to operate 100% of the time and the high pressure and surface scattering and spectroscopy instruments to receive beam time increases, will facilitate much more efficient use of the substantial investment in these instruments. The broad scientific community will benefit by the increase in the number of scientists who conduct cutting-edge research at GSECARS. The user program in stations 13ID-C (interface scattering) and 13ID-D (laser heated diamond anvil cell and large volume press) recommenced in June 2012. The operation of the 13ID-E microprobe station began in the Fall 2012 cycle (Oct.-Dec 2012). The upgraded canted beamlines double the amount of undulator beam time at Sector 13 and provide new capabilities including extended operations of the X-ray microprobe down to the sulfur K edge and enhanced brightness at high energy. The availability of the upgraded beamlines will advance the research being conducted at Sector 13.
Characterization of the Support and Drive System of the PETRA III APPLE Undulator
Bahrdt, J.; Baecker, H.-J.; Frentrup, W.; Gaupp, A.; Gottschlich, S.; Kuhn, C.; Scheer, M.; Schulz, B.; Gast, M.; Englisch, U.; Schoeps, A.; Tischer, M.
2010-06-23
Helmholtzzentrum Berlin has built an APPLE II undulator for the storage ring PETRA III. The device has a total length of 5m and a minimum gap of 11mm. The high magnetic forces in particular in the inclined mode have been analyzed by means of finite element methods (FEM). Specific mechanic components such as flexible joints have been optimized to cope with the gap- and shift-dependent 3D-forces and a sophisticated control and drive system has been implemented. After completion of the device, detailed laser interferometer measurements for all operation modes have been performed. The data are compared to the FEM simulations.
Single shot polarization characterization of XUV FEL pulses from crossed polarized undulators
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ferrari, E.; Allaria, E.; Buck, J.; De Ninno, G.; Diviacco, B.; Gauthier, D.; Giannessi, L.; Glaser, L.; Huang, Z.; Ilchen, M.; et al
2015-08-28
Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We research the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation.
Asgekar, V.; Lehnert, U.; Michel, P.
2012-01-15
A tapered undulator experiment was carried out at the ELBE far-infrared free electron laser (FEL). The oscillator FEL makes use of a hybrid optical resonator. The main motivation was to see whether the presence of a dispersive medium in the form of a waveguide in the resonator has any effect on the outcome. The FEL saturated power and the wavelength shifts have been measured as a function of both positive as well as negative undulator field amplitude tapering. In contrast to the typical high-gain FELs where positive tapering proves beneficial for the output power we observed an improvement of performance at negative taper. During the same experiments we studied the characteristics of the detuning curves. The width of the curves indicates a maximum small signal gain for zero taper while the output peak power increases with negative taper. The saturated power output, the detuning curve characteristics, and the wavelength shifts agrees with the theoretical predictions. Details of the experiment are presented.
sources of X-ray radiation. They constitute invaluable tools for a broad range of research1 ; however, their dependence on large- scale radiofrequency electron accelerators means that only a few of these sources exist-laboratory scale. Here, we demonstrate the generation of soft-X-ray undulator radiation with laser
Quantum effects in spontaneous emission by a relativistic, undulating electron beam
G. R. M. Robb; R. Bonifacio
2011-10-27
Current models of the effect of spontaneous emission on the electron beam dynamics neglect the discreteness of electron recoil associated with photon emission. We present a novel, one-dimensional model of the effect of spontaneous emission on the electron beam dynamics in an undulator both in the classical regime where discrete electron recoil is negligible, and the quantum regime where it is significant. It is shown that in the classical regime, continuous decrease of the average electron energy and diffusive growth of the electron energy spread occurs, in agreement with previous classical models. In the quantum regime, it is shown that the evolution of the electron momentum distribution occurs as discrete momentum groups according to a Poisson distribution. The narrow momentum features of the quantum regime may be useful for generation of coherent radiation, which relies on electron beams having sufficiently narrow momentum/energy distributions.
Folcia, C. L.; Etxebarria, J.; Ortega, J.
2007-07-15
X-ray diffraction diagrams of undulated smectic phases in bent-core liquid crystals have been theoretically studied. The intensities of the reflections have been obtained for different layer modulations, and a general expression has been deduced for orthogonal cells in terms of the different harmonics of the distortion. The case of sinusoidal modulation is especially simple and has been studied also in oblique cells. High-quality x-ray measurements of three compounds reported in the literature have been analyzed as examples. In all cases it has been deduced that the modulation is sinusoidal and its amplitude has been easily obtained by fitting the experimental intensities. Equatorial (h0) reflections have been also considered to obtain information about the structure of defects at the maxima and minima of the undulation.
Schneidmiller, E A
2015-01-01
We describe statistical and coherence properties of the radiation from x-ray free electron lasers (XFEL) operating in the post-saturation regime. We consider practical case of the SASE3 FEL at the European XFEL. We perform comparison of the main characteristics of the X-ray FEL operating in the post-saturation regime with and without undulator tapering: efficiency, coherence time and degree of transverse coherence.
Tatchyn, Roman; /SLAC
2011-09-09
Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.
Park, So Yeong; Hong, Chung Ki [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of)] [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Lim, Jun, E-mail: limjun@postech.ac.kr [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)] [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)
2014-04-15
We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 ?m (horizontal) × 50 ?m (vertical)
Beam Based Alignment of the TESLA X-ray FEL undulators B. Faatz Deutsches Elektronen the performance of the FEL is the overlap between electron beam and radiation field during the amplification The TESLA X-ray FEL laboratory is a proposed user facility in the wavelength range between ¼ Å and 6 nm
Experimental evidence of planar channeling in a periodically bent crystal
Bagli, E; Bellucci, V; Berra, E; Camattari, R; De Salvador, D; Germogli, G; Guidi, V; Lanzoni, L; Lietti, D; Mazzolari, A; Prest, M; Tikhomirov, V V; Vallazza, E
2014-01-01
The usage of a Crystalline Undulator (CU) has been identified as a promising solution for generating powerful and monochromatic $\\gamma$-rays. A CU was fabricated at SSL through the grooving method, i.e., by the manufacturing of a series of periodical grooves on the major surfaces of a crystal. The CU was extensively characterized both morphologically via optical interferometry at SSL and structurally via X-ray diffraction at ESRF. Then, it was finally tested for channeling with a 400 GeV/c proton beam at CERN. The experimental results were compared to Monte Carlo simulations. Evidence of planar channeling in the CU was firmly observed. Finally, the emission spectrum of the positron beam interacting with the CU was simulated for possible usage in currently existing facilities.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Individual Permit Storm Water Analytical Period Storm Water Analytical Period The Individual Permit authorizes the discharge of storm water associated with historical industrial...
De-Xing Kong; Kefeng Liu; Ming Shen
2008-08-30
In this letter we construct a new time-periodic solution of the vacuum Einstein's field equations whose Riemann curvature norm takes the infinity at some points. We show that this solution is intrinsically time-periodic and describes a time-periodic universe with the "black hole". New physical phenomena are investigated and new singularities are analyzed for this universal model.
Genealogy of periodic trajectories
de Adguiar, M.A.M.; Maldta, C.P.; de Passos, E.J.V.
1986-05-20
The periodic solutions of non-integrable classical Hamiltonian systems with two degrees of freedom are numerically investigated. Curves of periodic families are given in plots of energy vs. period. Results are presented for this Hamiltonian: H = 1/2(p/sub x//sup 2/ + p/sub y//sup 2/) + 1/2 x/sup 2/ + 3/2 y/sup 2/ - x/sup 2/y + 1/12 x/sup 4/. Properties of the families of curves are pointed out. (LEW)
Fourier series and periodicity
Donal F. Connon
2014-12-07
A large number of the classical texts dealing with Fourier series more or less state that the hypothesis of periodicity is required for pointwise convergence. In this paper, we highlight the fact that this condition is not necessary.
Broader source: Energy.gov [DOE]
DOE has published a Final Environmental Impact Statement (EIS), and the 30-day waiting period has ended. DOE is preparing a Record of Decision to announce and explain its chosen project alternative...
LYSING CELLS FOR NUCLEAR PROTEINS Wash 10 cm dish of cells with PBS.
Lamond, Angus I.
of shredding and syringing. Transfer the lysate to an Eppendorf tube when done, taking care to avoid any immediately to ice). Nuclear Lysis Buffer: Final Concentration Stock Solution Amount for 10 ml 50 mM Tris, p
Designs of SSRF Insertion Devices
Zhou, Q. G.; Chen, N.; Zhang, M.; Li, Y.; Su, W. L.
2007-01-19
Five IDs will be built for the Shanghai Synchrotron Radiation Facility (SSRF). Two identical mini-gap undulators with the period length 25mm and the minimum gap 6mm will use the in-vacuum technology and can operate in tapered mode. Two wigglers with the period lengths 7.9cm and 14cm and the same minimum gap 14mm will produce the peak fields of 1.2T and 1.94T. A variable polarization undulator of the APPLE-II type with 4.2m long and the period length 10cm can provide linearly, circularly and elliptically polarized radiation in a wide spectral range. This paper describes the magnet designs and the mechanical structure designs of these IDs.
Ball Packings with Periodic Constraints
Robert Connelly; Jeffrey D. Shen; Alexander D. Smith
2013-01-04
We call a periodic ball packing in d-dimensional Euclidean space periodically (strictly) jammed with respect to a period lattice if there are no nontrivial motions of the balls that preserve the period (that maintain some period with smaller or equal volume). In particular, we call a packing consistently periodically (strictly) jammed if it is periodically (strictly) jammed on every one of its periods. After extending a well-known bar framework and stress condition to strict jamming, we prove that a packing with period Lambda is consistently strictly jammed if and only if it is strictly jammed with respect to Lambda and consistently periodically jammed. We next extend a result about rigid unit mode spectra in crystallography to characterize periodic jamming on sublattices. After that, we prove that there are finitely many strictly jammed packings of m unit balls and other similar results. An interesting example shows that the size of the first sublattice on which a packing is first periodically unjammed is not bounded. Finally, we find an example of a consistently periodically jammed packing of low density \\delta = \\frac{4 \\pi}{6 \\sqrt{3} + 11} + \\epsilon ~ 0.59, where \\epsilon is an arbitrarily small positive number. Throughout the paper, the statements for the closely related notions of periodic infinitesimal rigidity and affine infinitesimal rigidity for tensegrity frameworks are also given.
G. R. M. Robb; R. Bonifacio
2012-03-12
In arXiv:1202.0691, Geloni et al. criticise our recent work describing the spontaneous emission by a relativistic, undulating electron beam. In particular they claim that our prediction of a quantum regime in which evolution of the electron momentum distribution occurs as a sequential population of discrete momentum groups rather than in terms of a drift-diffusion process is unphysical and artificial. We show that the criticism of our model contained in arXiv:1202.0691 is unfounded.
LCLS CDR Chapter 8 - Undulator
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResource and Job EventpopLA349226762Contributions toA14578
Representing Periodic Functions by Fourier
Vickers, James
Representing Periodic Functions by Fourier Series 23.2 Introduction In this Section we show how, then the Fourier series expansion takes the form: f(t) = a0 2 + n=1 (an cos nt + bn sin nt) Our main purpose here Fourier coefficients of a function of period 2 calculate Fourier coefficients of a function of general
Shortest recurrence periods of novae
Kato, Mariko [Department of Astronomy, Keio University, Hiyoshi, Yokohama 223-8521 (Japan); Saio, Hideyuki [Astronomical Institute, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Hachisu, Izumi [Department of Earth Science and Astronomy, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Nomoto, Ken'ichi, E-mail: mariko@educ.cc.keio.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)
2014-10-01
Stimulated by the recent discovery of the 1 yr recurrence period nova M31N 2008-12a, we examined the shortest recurrence periods of hydrogen shell flashes on mass-accreting white dwarfs (WDs). We discuss the mechanism that yields a finite minimum recurrence period for a given WD mass. Calculating the unstable flashes for various WD masses and mass accretion rates, we identified a shortest recurrence period of about two months for a non-rotating 1.38 M {sub ?} WD with a mass accretion rate of 3.6 × 10{sup –7} M {sub ?} yr{sup –1}. A 1 yr recurrence period is realized for very massive (? 1.3 M {sub ?}) WDs with very high accretion rates (? 1.5 × 10{sup –7} M {sub ?} yr{sup –1}). We revised our stability limit of hydrogen shell burning, which will be useful for binary evolution calculations toward Type Ia supernovae.
Analytic aspects of periodic instantons
Charbonneau, Benoit, 1976-
2004-01-01
The main result is a computation of the Nahm transform of a SU(2)-instanton over R x T³, called spatially-periodic instanton. It is a singular monopole over T³, a solution to the Bogomolny equation, whose rank is computed ...
Stratified Steady Periodic Water Waves
Samuel Walsh
2009-02-11
This paper considers two-dimensional stratified water waves propagating under the force of gravity over an impermeable flat bed and with a free surface. We prove the existence of a global continuum of classical solutions that are periodic and traveling. These waves, moreover, can exhibit large density variation, speed and amplitude.
ANDERSON LOCALIZATION FOR TIME PERIODIC
disorder, Anderson localization in Z d is stable un- der localized time-periodic perturbations by proving random Schrodinger operators at large disorder has been well known since the seminal work of Fr is approximated by the potential V . The equation governing the system is (1.5) i @ @t = (#1; + V ) on Z d #2
Advanced downhole periodic seismic generator
Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)
1991-07-16
An advanced downhole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.
Down hole periodic seismic generator
Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)
1989-01-01
A down hole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.
Frozen light in periodic metamaterials
A. Figotin; I. Vitebskiy
2006-09-16
Wave propagation in spatially periodic media, such as photonic crystals, can be qualitatively different from any uniform substance. The differences are particularly pronounced when the electromagnetic wavelength is comparable to the primitive translation of the periodic structure. In such a case, the periodic medium cannot be assigned any meaningful refractive index. Still, such features as negative refraction and/or opposite phase and group velocities for certain directions of light propagation can be found in almost any photonic crystal. The only reservation is that unlike hypothetical uniform left-handed media, photonic crystals are essentially anisotropic at frequency range of interest. Consider now a plane wave incident on a semi-infinite photonic crystal. One can assume, for instance, that in the case of positive refraction, the normal components of the group and the phase velocities of the transmitted Bloch wave have the same sign, while in the case of negative refraction, those components have opposite signs. What happens if the normal component of the transmitted wave group velocity vanishes? Let us call it a "zero-refraction" case. At first sight, zero normal component of the transmitted wave group velocity implies total reflection of the incident wave. But we demonstrate that total reflection is not the only possibility. Instead, the transmitted wave can appear in the form of an abnormal grazing mode with huge amplitude and nearly tangential group velocity. This spectacular phenomenon is extremely sensitive to the frequency and direction of propagation of the incident plane wave. These features can be very attractive in numerous applications, such as higher harmonic generation and wave mixing, light amplification and lasing, highly efficient superprizms, etc.
Long-period pulses Motivation Developed program Results Long-period disturbances in records of Swiss
Cerveny, Vlastislav
Long-period pulses Motivation Developed program Results Long-period disturbances in records 2014 #12;Long-period pulses Motivation Developed program Results Index 1 Long-period pulses in records 2 Motivation for the study 3 Developed program 4 Results #12;Long-period pulses Motivation Developed
A Periodic Solution to Impulsive Logistic Equation
Gyong-Chol Kim; Hyong-Chol O; Sang-Mun Kim; Chol Kim
2014-03-28
In this paper is provided a new representation of periodic solution to the impulsive Logistic equation considered in [7].
Periods Associated to Algebraic Cycles Spencer Bloch
Bloch, Spencer
K0(X) = CHp (X)Q Spencer Bloch () Periods Associated to Algebraic Cycles March 3, 2014 Albert) CHp(X, n) := H-n(Zp(X, ·)). Spencer Bloch () Periods Associated to Algebraic Cycles March 3, 2014 ) - Zp (X) CHp(X, n) := H-n(Zp(X, ·)). Spencer Bloch () Periods Associated to Algebraic Cycles March 3
Detection of superimposed periodic signals using wavelets
X. Otazu; M. Ribo; M. Peracaula; J. M. Paredes; J. Nunez
2002-02-05
In this paper we present a wavelet based algorithm that is able to detect superimposed periodic signals in data with low signal-noise ratio. In this context, the results given by classical period determination methods highly depend on the intrinsic characteristics of each periodic signal, like amplitude or profile. It is then difficult to detect the different periods present in the data set. The results given by the wavelet based method for period determination we present here are independent of the characteristics of the signals.
Seismic isolation of two dimensional periodic foundations
Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.
2014-07-28
Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5?Hz to 50?Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.
Do triatomic molecules echo atomic periodicity?
Hefferlin, R. Barrow, J.
2015-03-30
Demonstrations of periodicity among triatomic-molecular spectroscopic constants underscore the role of the periodic law as a foundation of chemistry. The objective of this work is to prepare for another test using vibration frequencies ?{sub 1} of free, ground-state, main-group triatomic molecules. Using data from four data bases and from computation, we have collected ?{sub 1} data for molecules formed from second period atoms.
Pricing Conspicuous Consumption Products in Recession Periods ...
2012-09-26
cally used in chemical engineering, e.g., to avoid irreversible reactions in ... Our basic problem is based on an economic setting with a recession period followed.
Inference and Visualization of Periodic Sequences
Sun, Ying
2011-10-21
are evenly spaced in time. The period is estimated by a "leave-out-one-cycle" version of cross-validation (CV) and complements the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes...
Periodic cellular automata and Bethe ansatz
Atsuo Kuniba; Akira Takenouchi
2006-01-07
We review and generalize the recent progress in a soliton cellular automaton known as the periodic box-ball system. It has the extended affine Weyl group symmetry and admits the commuting transfer matrix method and the Bethe ansatz at q=0. Explicit formulas are proposed for the dynamical period and the number of states characterized by conserved quantities.
Periodic Measurement of Advertising Effectiveness Using Multiple-Test-Period Geo Experiments
Cortes, Corinna
of ad effectiveness measurements across time. Additionally, the experimental units should rotate betweenPeriodic Measurement of Advertising Effectiveness Using Multiple-Test-Period Geo Experiments Jon experiments to the measurement of advertising effectiveness. One reason this method of measurement
New Science with the APS Superconducting Undulator
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of the Nature Materials News & Views article, "Quasicrystals: Model structures," by Marc de Boissieu, which can be read here; and the APS science and research highlight found...
Transverse Gradient Undulator Huang, Zhirong; Ding, Yuantao;...
Office of Scientific and Technical Information (OSTI)
B.; LBL, Berkeley 43 PARTICLE ACCELERATORS; ACCELERATORS; ELECTRON BEAMS; ELECTRONS; FREE ELECTRON LASERS; LASERS; PERFORMANCE; PLASMA GUNS; RADIATIONS; WIGGLER MAGNETS...
Dynamics of Periodically-kicked Oscillators
Kevin K. Lin; Lai-Sang Young
2010-04-21
We review some recent results surrounding a general mechanism for producing chaotic behavior in periodically-kicked oscillators. The key geometric ideas are illustrated via a simple linear shear model.
Impact of Motor Failures on Payback Periods
Cheek, K. F.; Pillay, P.; Dudley, K. J.
1995-01-01
This paper uses MotorMaster and Vaughen's Complete Price Guide to determine payback periods for different motor failure scenarios. Some scenarios considered are rewinds, reconditions, and replacement of bearings. Prices for these repairs...
University of Oregon Libraries Types of Periodicals
Lockery, Shawn
University of Oregon Libraries Types of Periodicals Scholarly Sources Popular Sources SCHOLARLY American Quarterly RN Automotive News Library Journal Restaurants & Institutions Chemical Engineering News & biographical information Statistics, including forecasts Some book reviews Commentary on political & social
QM/MM description of periodic systems
Doll, K
2015-01-01
A QM/MM implementation for periodic systems is reported. This is done for the case of molecules and for systems with two and three-dimensional periodicity, which is suitable to model electrolytes in contact with electrodes. Tests on different water-containing systems, ranging from the water dimer up to liquid water indicate the correctness of the scheme. Furthermore, molecular dynamics simulations are performed, as a possible direction to study realistic systems.
The periodicity of the eta Carinae events
A. Damineli; M. F. Corcoran; D. J. Hillier; O. Stahl; R. S. Levenhagen; N. V. Leister; J. H. Groh; M. Teodoro; J. F. Albacete Colombo; F. Gonzalez; J. Arias; H. Levato; M. Grosso; N. Morrell; R. Gamen; G. Wallerstein; V. Niemela
2007-11-27
Extensive spectral observations of eta Carinae over the last cycle, and particularly around the 2003.5 low excitation event, have been obtained. The variability of both narrow and broad lines, when combined with data taken from two earlier cycles, reveal a common and well defined period. We have combined the cycle lengths derived from the many lines in the optical spectrum with those from broad-band X-rays, optical and near-infrared observations, and obtained a period length of 2022.7+-1.3 d. Spectroscopic data collected during the last 60 years yield an average period of 2020+-4 d, consistent with the present day period. The period cannot have changed by more than $\\Delta$P/P=0.0007 since 1948. This confirms the previous claims of a true, stable periodicity, and gives strong support to the binary scenario. We have used the disappearance of the narrow component of HeI 6678 to define the epoch of the Cycle 11 minimum, T_0=JD 2,452,819.8. The next event is predicted to occur on 2009 January 11 (+-2 days). The dates for the start of the minimum in other spectral features and broad-bands is very close to this date, and have well determined time delays from the HeI epoch.
Kepler and the long-period variables
Hartig, Erich; Lebzelter, Thomas [University of Vienna, Department of Astrophysics, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Cash, Jennifer [Department of Biological and Physical Sciences, South Carolina State University, P.O. Box 7024, Orangeburg, SC 29117 (United States); Hinkle, Kenneth H.; Mighell, Kenneth J. [National Optical Astronomy Observatories, P.O. Box 26732, Tucson, AZ 85726 (United States); Walter, Donald K., E-mail: erich.hartig@univie.ac.at, E-mail: thomas.lebzelter@univie.ac.at, E-mail: jcash@physics.scsu.edu, E-mail: hinkle@noao.edu, E-mail: mighell@noao.edu, E-mail: dkw@physics.scsu.edu [Department of Biological and Physical Sciences, South Carolina State University, P.O. Box 7296, Orangeburg, SC 29117 (United States)
2014-12-01
High-precision Kepler photometry is used to explore the details of asymptotic giant branch (AGB) light curves. Since AGB variability has a typical timescale on the order of a year, we discuss at length the removal of long-term trends and quarterly changes in Kepler data. Photometry for a small sample of nine semi-regular (SR) AGB stars is examined using a 30 minute cadence over a period of 45 months. While undergoing long-period variations of many magnitudes, the light curves are shown to be smooth at the millimagnitude level over much shorter time intervals. No flares or other rapid events were detected on a sub-day timescale. The shortest AGB period detected is on the order of 100 days. All the SR variables in our sample are shown to have multiple modes. This is always the first overtone, typically combined with the fundamental. A second common characteristic of SR variables is shown to be the simultaneous excitation of multiple closely separated periods for the same overtone mode. Approximately half the sample had a much longer variation in the light curve, likely a long secondary period (LSP). The light curves were all well represented by a combination of sinusoids. However, the properties of the sinusoids are time variable, with irregular variations present at low levels. No non-radial pulsations were detected. It is argued that the LSP variation seen in many SR variables is intrinsic to the star and linked to multiple mode pulsation.
Periodic subsystem density-functional theory
Genova, Alessandro; Pavanello, Michele; Ceresoli, Davide
2014-11-07
By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn–Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn–Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.
Magnetomechanically induced long period fiber gratings
Causado-Buelvas, Jesus D.; Gomez-Cardona, Nelson D.; Torres, Pedro
2008-04-15
In this work, we report a simple, flexible method to create long period fiber gratings mechanically by controlling the repulsion/attraction force between two magnets that pressing a plate with a periodic array of small glass cylinders to a short length of optical fiber. Via the photoelastic effect, the pressure points induce the required periodic refractive index modulation to create the LPFG. We found that the induced device exhibits spectral characteristics similar to those of other types of LPFG. As the optical properties of LPFGs are directly related to the nature of the applied perturbations, we show, to our knowledge for the frrst time, how is the evolution of birefringence effects in mechanically induced LPFGs.
Sequential conditions for fixed and periodic points
Peters, Burnis Charles
1970-01-01
) (Member) ~A (Month) 1970 (Year) ~04SQQ ABSTRACT Sec, uential Conditions fo. Fixed and Periodic Points (August 1970) Burnis C. Peter, Jr. , B. A. , Texas ASM University; M. S. , Texas A&M University Directed by: Jack Bryant and L. F. Guseman, Jr.... Let (X, d) be a metric space and f a selfmap of X. It is shown that a number of known theorems on the existence of fixed and periodic points are related through simple properties of the n sequence (f ) of iterates . ACMOVI. EDGEMENTS I wish...
Emergent hyperuniformity in periodically-driven emulsions
Joost H. Weijs; Raphaël Jeanneret; Rémi Dreyfus; Denis Bartolo
2015-04-28
We report the emergence of large-scale hyperuniformity in microfluidic emulsions. Upon periodic driving confined emulsions undergo a first-order transition from a reversible to an irreversible dynamics. We evidence that this dynamical transition is accompanied by structural changes at all scales yielding macroscopic yet finite hyperuniform structures. Numerical simulations are performed to single out the very ingredients responsible for the suppression of density fluctuations. We show that as opposed to equilibrium systems the long-range nature of the hydrodynamic interactions are not required for the formation of hyperuniform patterns, thereby suggesting a robust relation between reversibility and hyperuniformity which should hold in a broad class of periodically driven materials.
Localization length of nearly periodic layered metamaterials
del Barco, O
2015-01-01
We have analyzed numerically the localization length of light $\\xi$ for nearly periodic arrangements of homogeneous stacks (formed exclusively by right-handed materials) and mixed stacks (with alternating right and left-handed metamaterials). Layers with index of refraction $n_1$ and thickness $L_1$ alternate with layers of index of refraction $n_2$ and thickness $L_2$. Positional disorder has been considered by shifting randomly the positions of the layer boundaries with respect to periodic values. For homogeneous stacks, we have shown that the localization length is modulated by the corresponding bands and that $\\xi$ is enhanced at the center of each allowed band. In the limit of long-wavelengths $\\lambda$, the parabolic behavior previously found in purely disordered systems is recovered, whereas for $\\lambda \\ll L_1 + L_2$ a saturation is reached. In the case of nearly periodic mixed stacks with the condition $|n_1 L_1|=|n_2 L_2|$, instead of bands there is a periodic arrangement of Lorenztian resonances, ...
Utility Building Analysis Billing Period: NOV -2013
ELECTRICITY Consumption MUNICIPAL WATER Consumption 8 CCF STEAM Consumption CHILLED WATER Consumption GAS Building Analysis Billing Period: NOV - 2013 032 JACKSON HALL: 150,393 Square Feet ELECTRICITY Consumption,550 Square Feet ELECTRICITY Consumption 114,185 KWHRS MUNICIPAL WATER Consumption 1,423 CCF STEAM Consumption
Periodic Reward-Based Scheduling and Its
Aydin, Hakan
catastrophic. Examples of real-time systems can be found in control systems of nuclear power plants, air36 Periodic Reward-Based Scheduling and Its Application to Power-Aware Real-Time Systems Hakan ........................... 36-9 Modeling Real-Time Workload and Energy on a Variable Speed CPU · Correlating Real-Time Power
Quantum transport calculations using periodic boundaryconditions
Wang, Lin-Wang
2004-06-15
An efficient new method is presented to calculate the quantum transports using periodic boundary conditions. This method allows the use of conventional ground state ab initio programs without big changes. The computational effort is only a few times of a normal groundstate calculations, thus is makes accurate quantum transport calculations for large systems possible.
Elsevier Journal Specific Embargo Periods 2013 Journal Name Issn Embargo Period
Ayala-Rincón, Mauricio
Elsevier Journal Specific Embargo Periods 2013 Journal Name Issn Embargo Period ACADEMIC PEDIATRICS 18762859 12 ACADEMIC RADIOLOGY 10766332 12 ACC CARDIOSOURCE REVIEW JOURNAL 15568571 12 ACCIDENT ANALYSIS 18759637 24 AEROSPACE SCIENCE AND TECHNOLOGY 12709638 24 AESTHETIC SURGERY JOURNAL 1090820X 12 AESTHETISCHE
The Super Period Matrix With Ramond Punctures
Edward Witten
2015-01-11
We generalize the super period matrix of a super Riemann surface to the case that Ramond punctures are present. For a super Riemann surface of genus g with 2r Ramond punctures, we define, modulo certain choices that generalize those in the classical theory (and assuming a certain generic condition is satisfied), a g|r x g|r period matrix that is symmetric in the Z_2-graded sense. As an application, we analyze the genus 2 vacuum amplitude in string theory compactifications to four dimensions that are supersymmetric at tree level. We find an explanation for a result that has been found in orbifold examples in explicit computations by D'Hoker and Phong: with their integration procedure, the genus 2 vacuum amplitude always vanishes "pointwise" after summing over spin structures, and hence is given entirely by a boundary contribution.
Beat Cepheid Period Ratios from OPAL Opacities
S. M. Morgan; D. L. Welch
1997-06-26
The discovery of a large number of beat Cepheids in the Large Magellanic Cloud in the MACHO survey, provides an opportunity to compare the characteristics of such Cepheids over a range of metallicities. We produced a large grid of linear nonadiabatic pulsation models using the OPAL opacity tables and with compositions corresponding to those of the Milky Way, and the Large and Small Magellanic Clouds. Using the relationship between the period ratio and the main pulsation period, we are able to define a range of models which correspond to the observed beat Cepheids, and thereby constrain the physical characteristics of the LMC beat Cepheids. We are also able to make some predictions about the nature of the yet-to-be-discovered SMC beat Cepheids.
Policy Flash 2013-41 Contracts Periods of Performance Exceeding...
1 Contracts Periods of Performance Exceeding 5 Years Policy Flash 2013-41 Contracts Periods of Performance Exceeding 5 Years Attached is Policy Flash 2013-41 Contracts Periods of...
Emissions from Idling Trucks for Extended Time Periods | Department...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Idling Trucks for Extended Time Periods Emissions from Idling Trucks for Extended Time Periods 2002 DEER Conference Presentation: Oak Ridge National Laboratory 2002deerlewis.pdf...
Microsoft Word - Alcoa Extended Initial Period ROD - 2010-10...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Extended Initial Period... 6 b. Benefits to BPA will equal or exceed costs for the Extended Initial Period of the Block Contract. ......
DOE Extends Public Comment Period for the Draft Uranium Leasing...
Extends Public Comment Period for the Draft Uranium Leasing Program Programmatic Environmental Impact Statement DOE Extends Public Comment Period for the Draft Uranium Leasing...
Down-hole periodic seismic generator
Hardee, H.C.; Hills, R.G.; Striker, R.P.
1982-10-28
A down hole periodic seismic generator system is disclosed for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.
Property:TimePeriod | Open Energy Information
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 QA:QA J-E-1 SECTION JEnvironmental Jump to:EA EIS Report Url JumpTechnology Jump to: navigation, search ThisTimePeriod
Electromagnetic Siegert states for periodic dielectric structures
Friends R. Ndangali; Sergei V. Shabanov
2011-08-09
The formalism of Siegert states to describe the resonant scattering in quantum theory is extended to the resonant scattering of electromagnetic waves on periodic dielectric arrays. The excitation of electromagnetic Siegert states by an incident wave packet and their decay is studied. The formalism is applied to develop a theory of coupled electromagnetic resonances arising in the electromagnetic scattering problem for two such arrays separated by a distance 2h (or, generally, when the physical properties of the scattering array depend on a real coupling parameter h). Analytic properties of Siegert states as functions of the coupling parameter h are established by the Regular Perturbation Theorem which is an extension the Kato-Rellich theorem to the present case. By means of this theorem, it is proved that if the scattering structure admits a bound state in the radiation continuum at a certain value of the coupling parameter h, then there always exist regions within the structure in which the near field can be amplified as much as desired by adjusting the value of h. This establishes a rather general mechanism to control and amplify optical nonlinear effects in periodically structured planar structures possessing a nonlinear dielectric susceptibility.
Dynamical system theory of periodically collapsing bubbles
Yukalov, V I; Sornette, D
2015-01-01
We propose a reduced form set of two coupled continuous time equations linking the price of a representative asset and the price of a bond, the later quantifying the cost of borrowing. The feedbacks between asset prices and bonds are mediated by the dependence of their "fundamental values" on past asset prices and bond themselves. The obtained nonlinear self-referencing price dynamics can induce, in a completely objective deterministic way, the appearance of periodically exploding bubbles ending in crashes. Technically, the periodically explosive bubbles arise due to the proximity of two types of bifurcations as a function of the two key control parameters $b$ and $g$, which represent, respectively, the sensitivity of the fundamental asset price on past asset and bond prices and of the fundamental bond price on past asset prices. One is a Hopf bifurcation, when a stable focus transforms into an unstable focus and a limit cycle appears. The other is a rather unusual bifurcation, when a stable node and a saddle...
Quarterly Construction Status Report Period Ending: December 31, 2014
Alpay, S. Pamir
Cast Stone Replacement 901833 Quarterly Construction Status Report for Period Ending: December 31, 2014
A field expansions method for scattering by periodic multilayered media
Malcolm, Alison E.
2010-01-01
The interaction of acoustic and electromagnetic waves with periodic structures plays an important role
Xifeng Su; Lei Zhang; Rafael de la Llave
2015-03-11
We consider 1-D quasi-periodic Frenkel-Kontorova models (describing, for example, deposition of materials in a quasi-periodic substratum). We study the existence of equilibria whose frequency (i.e. the inverse of the density of deposited material) is resonant with the frequencies of the substratum. We study perturbation theory for small potential. We show that there are perturbative expansions to all orders for the quasi-periodic equilibria with resonant frequencies. Under very general conditions, we show that there are at least two such perturbative expansions for equilibria for small values of the parameter. We also develop a dynamical interpretation of the equilibria in these quasi-periodic media. We show that the dynamical system has very unusual properties. Using these, we obtain results on the Lyapunov exponents of the resonant quasi-periodic solutions. In a companion paper, we develop a rather unusual KAM theory (requiring new considerations) which establishes that the perturbative expansions converge when the perturbing potentials satisfy a one-dimensional constraint.
Single-periodic-film optical bandpass filter
Niraula, Manoj; Magnusson, Robert
2015-01-01
Resonant periodic surfaces and films enable new functionalities with wide applicability in practical optical systems. Their material sparsity, ease of fabrication, and minimal interface count provide environmental and thermal stability and robustness in applications. Here we report an experimental bandpass filter fashioned in a single patterned layer on a substrate. Its performance corresponds to bandpass filters requiring perhaps 30 traditional thin-film layers as shown by an example. We demonstrate an ultra-narrow, high-efficiency bandpass filter with extremely wide, flat, and low sidebands. This class of devices is designed with rigorous solutions of the Maxwell equations while engaging the physical principles of resonant waveguide gratings. The proposed technology is integration-friendly and opens doors for further development in various disciplines and spectral regions where thin-film solutions are traditionally applied.
Quasi-periodic oscillations of perturbed tori
Parthasarathy, Varadarajan; Kluzniak, Wlodek
2015-01-01
We performed axisymmetric hydrodynamic simulations of perturbed tori orbiting a black hole. The tori in equilibrium were constructed with a constant distribution of angular momentum in a pseudo-Newtonian potential (Klu{\\'z}niak-Lee). Epicyclic motions were triggered by adding sub-sonic velocity fields: radial, vertical and diagonal to the tori in equilibrium. As the perturbed tori evolved in time, we measured $L_{2}$ norm of density and obtained the power spectrum of $L_{2}$ norm which manifested eigenfrequencies of tori modes. We observe a pair of modes which occur in an approximate 3:2 ratio. Results from our simulations are relevant in the context of high-frequency quasi-periodic oscillations (HF QPOs) observed in stellar-mass black hole binaries.
Imtak Jeon; Neil Lambert; Paul Richmond
2012-11-29
We consider periodic arrays of M2-branes in the ABJM model in the spirit of a circle compactification to D2-branes in type IIA string theory. The result is a curious formulation of three-dimensional maximally supersymmetric Yang-Mills theory in terms of fermions, seven transverse scalars, a non-dynamical gauge field and an additional scalar `dual gluon'. Upon further T-duality on a transverse torus we obtain a non-manifest-Lorentz-invariant description of five-dimensional maximally supersymmetric Yang-Mills. Here the additional scalar field can be thought of as the components of a two-form along the torus. This action can be viewed as an M-theory description of M5-branes on ${\\mathbb T}^3$.
Periodic relativity: basic framework of the theory
Vikram H. Zaveri
2014-11-25
An alternative gravity theory is proposed which does not rely on Riemannian geometry and geodesic trajectories. The theory named periodic relativity (PR) does not use the weak field approximation and allows every two body system to deviate differently from the flat Minkowski metric. PR differs from general relativity (GR) in predictions of the proper time intervals of distant objects. PR proposes a definite connection between the proper time interval of an object and gravitational frequency shift of its constituent particles as the object travels through the gravitational field. PR is based on the dynamic weak equivalence principle which equates the gravitational mass with the relativistic mass. PR provides very accurate solutions for the Pioneer anomaly and the rotation curves of galaxies outside the framework of general relativity. PR satisfies Einstein's field equations with respect to the three major GR tests within the solar system and with respect to the derivation of Friedmann equation in cosmology. This article defines the underlying framework of the theory.
Lab 7: Fourier analysis and synthesis Fourier series (periodic phenomena)
Gustafsson, Torgny
Lab 7: Fourier analysis and synthesis · Fourier series (periodic phenomena) · Fourier transform (aperiodic phenomena) · Fast Fourier transform (FFT) The Fourier Transform and its Applications Brad G A powerful analytic tool that has many applications.... #12;Applications of Fourier analysis Periodic
Entrainment control of chaos near unstable periodic orbits
R. Mettin
1996-10-16
It is demonstrated that improved entrainment control of chaotic systems can maintain periodic goal dynamics near unstable periodic orbits without feedback. The method is based on the optimization of goal trajectories and leads to small open-loop control forces.
Classical Propagation of Light in Spatio-Temporal Periodic Media
Alexandrov, B S; Findikoglu, A T; Bishop, A R; Kostadinov, I Z
2006-01-01
We analyze the propagation of electromagnetic waves in media where the dielectric constants undergo rapid temporal periodic modulation. Both spatially homogeneous and periodic media are studied. Fast periodic temporal modulation of the dielectric constant of a homogeneous medium leads to existence of photonic band-gap like phenomena. In the presence of both spatial and tem- poral periodicity the electromagnetic spectrum is described in a four-dimensional cube, defining an effective Brillouin zone. In the case of incommensurability between space and time periodicities, completely dispersed point spectra exist.
Periodicals collection management using a decision support system
Compton, M.L.; Moser, E.C.
1993-12-31
Sandia National Laboratories is a multiprogram national laboratory established in 1949. The Library currently uses DOBIS for its automated system, including the Periodicals Control function for periodical check-in. DOBIS performs processing and control functions adequately, but could not meet our reporting needs. Therefore the Library`s Periodicals Decision Team decided that they needed another ``system`` for collection management. A Periodicals Decision Support System was created using information downloaded from DOBIS and uploaded into dBASE IV. The Periodical Decision Support System functions as an information-processing system that has aided us in making collection management decisions for periodicals. It certainly allows us to do interactive ad-hoc analysis; although there are no modeling tools currently incorporated in the system. We hope that these modeling tools will come later. We have been gathering information and developing needed reports to achieve this goal.
Multilevel interference lithography--fabricating sub-wavelength periodic nanostructures
Chang, Chih-Hao, 1980-
2008-01-01
Periodic nanostructures have many exciting applications, including high-energy spectroscopy, patterned magnetic media, photonic crystals, and templates for self-assembly. Interference lithography (IL) is an attractive ...
Department of Energy Announces Plans for Additional Comment Period...
Office of Environmental Management (EM)
Department of Energy Announces Plans for Additional Comment Period on National Interest Electric Transmission Corridors Department of Energy Announces Plans for Additional Comment...
Extension of Comment Period on the Draft Integrated, Interagency...
of Comment Period on the Draft Integrated, Interagency Pre-Application (IIP) Process for Electric Transmission Projects Requiring Federal Authorizations Extension of Comment...
Analysis of Periodic GrowthDisturbance Models Timothy C. Reluga
Reluga, Tim
and may include forest fires, volcanic eruptions, and hurricanes, occur quickly, perhaps over a period succession around disturbances like forest fires. Andrewartha and Birch (1978) proposed that disturbances
EIS-0431: Extension of Public Comment Period | Department of...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Comment Period Hydrogen Energy California's Integrated Gasification Combined Cycle and Carbon Capture and Sequestration Project, CA The U.S. Department of Energy (DOE) published...
Quality of monitoring of stochastic events by periodic and ...
David K. Y. Yau, Nung Kwan Yip, Chris Y. T. Ma, Nageswara S. V. Rao, Mallikarjun Shankar
2010-08-28
sensor monitoring a PoI may be periodically turned off to conserve energy, thereby ... In traditional public safety work, policemen or security guards are on.
Quality of Monitoring of Stochastic Events by Periodic & Proportional ...
2008-12-09
be periodically turned off to conserve energy, thereby .... ing resources to the different parts in proportion ... riodically turn off the sensor to conserve energy, so.
EIS-0431: Extension of public comment period; Notice of public...
EIS-0431: Extension of public comment period; Notice of public hearing; Correction Hydrogen Energy California's Integrated Gasification Combined Cycle and Carbon Capture and...
Pulse vaccination in the periodic infection rate SIR epidemic model
Zhen Jin; Mainul Haque; Quanxing Liu
2006-06-09
A pulse vaccination SIR model with periodic infection rate $\\beta (t)$ have been proposed and studied. The basic reproductive number $R_0$ is defined. The dynamical behaviors of the model are analyzed with the help of persistence, bifurcation and global stability. It has been shown that the infection-free periodic solution is globally stable provided $R_0 1$. Standard bifurcation theory have been used to show the existence of the positive periodic solution for the case of $R_0 \\to1^+$. Finally, the numerical simulations have been performed to show the uniqueness and the global stability of the positive periodic solution of the system.
CEQ Extends Comment Period on Revised Draft Guidance on Consideration...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
on Revised Draft Guidance on Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews CEQ Extends Comment Period on Revised Draft Guidance on...
DOE Extends Public Comment Period for Uranium Program Environmental...
Office of Environmental Management (EM)
Uranium Program Environmental Impact Statement DOE Extends Public Comment Period for Uranium Program Environmental Impact Statement April 18, 2013 - 1:08pm Addthis Contractor, Bob...
Guidance on the Required Period for Grantees to Obligate Funds...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
on the Required Period for Grantees to Obligate Funds and the Procedures for Reporting of Obligated Funds for the Energy Efficiency Conservation Block Grant (EECBG) Program...
Pressure-driven reconnection and quasi periodical oscillations in plasmas
Paccagnella, R., E-mail: roberto.paccagnella@igi.cnr.it [Consorzio RFX and Istituto Gas Ionizzati del Consiglio Nazionale delle Ricerche (CNR), Padova (Italy)
2014-03-15
This paper presents a model for an ohmically heated plasma in which a feedback exists between thermal conduction and transport, on one side, and the magneto-hydro-dynamical stability of the system, on the other side. In presence of a reconnection threshold for the magnetic field, a variety of periodical or quasi periodical oscillations for the physical quantities describing the system are evidenced. The model is employed to interpret the observed quasi periodical oscillations of electron temperature and perturbed magnetic field around the so called “Single Helical” state in the reversed field pinch, but its relevance for other periodical phenomena observed in magnetic confinement systems, especially in tokamaks, is suggested.
Dual periodicities in the rotational modulation of Saturn narrowband emissions
Gurnett, Donald A.
Dual periodicities in the rotational modulation of Saturn narrowband emissions S.Y. Ye,1 D. A emissions is examined, restricting the spacecraft location to either the northern or the southern hemisphere of Saturn. It is found that in both hemispheres, the modulation period of 5 kHz narrowband emissions has two
Homogenization of linear spatially periodic electronic Michel Lenczner
Homogenization of linear spatially periodic electronic circuits Michel Lenczner January 20, 2006 Abstract: In this paper we establish a simplified model of general spatially periodic linear electronic is reported. 1 Introduction It is well known that when the size of an analog electronic network increases too
Efficient Mining of Partial Periodic Patterns in Time Series Database
Dong, Guozhu
Efficient Mining of Partial Periodic Patterns in Time Series Database In ICDE 99 Jiawei Han \\Lambda peri odic patterns in timeseries databases, is an interesting data mining problem. Previous studies several algorithms for efficient mining of par tial periodic patterns, by exploring some interesting
Multivariate periodic wavelet analysis Dirk Langemann, Jurgen Prestin
Prestin, JÃ¼rgen
Multivariate periodic wavelet analysis Dirk Langemann, JÂ¨urgen Prestin University of LÂ¨ubeck, Institute of Mathematics, Wallstr. 40, D-23560 LÂ¨ubeck, Germany Abstract General multivariate periodic are generalized to multivariate shift invariant spaces on non-tensor-product pat- terns. In particular
Saving and Using Encountered Information: Implications for Electronic Periodicals
Marshall, Cathy
Saving and Using Encountered Information: Implications for Electronic Periodicals Catherine C of a focus on electronic publications, we undertook an exploratory study of how people saved and used study participants had examples of materials they had deliberately saved from periodicals, ranging from
Optical characterization of periodically-poled KTiOPO4
Exter, Martin van
Optical characterization of periodically-poled KTiOPO4 W. H. Peeters and M. P. van Exter Huygens-conversion(SPDC) give a direct visualization of the poling quality of a periodically-poled crystal. Identical Maker with small and slowly-varying deformations of the poling structure. Our theoretical model, based on a Fourier
Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities
Harrison; Neil (Santa Fe, NM), Singleton; John (Los Alamos, NM), Migliori; Albert (Santa Fe, NM)
2008-08-05
A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.
Unstable periodic orbits in a chaotic meandering jet flow
Uleysky, M Yu; Prants, S V; 10.1088/1751-8113/41/21/215102
2012-01-01
We study the origin and bifurcations of typical classes of unstable periodic orbits in a jet flow that was introduced before as a kinematic model of chaotic advection, transport and mixing of passive scalars in meandering oceanic and atmospheric currents. A method to detect and locate the unstable periodic orbits and classify them by the origin and bifurcations is developed. We consider in detail period-1 and period-4 orbits playing an important role in chaotic advection. We introduce five classes of period-4 orbits: western and eastern ballistic ones, whose origin is associated with ballistic resonances of the fourth order, rotational ones, associated with rotational resonances of the second and fourth orders, and rotational-ballistic ones associated with a rotational-ballistic resonance. It is a new kind of nonlinear resonances that may occur in chaotic flow with jets and/or circulation cells. Varying the perturbation amplitude, we track out the origin and bifurcations of the orbits for each class.
Unstable periodic orbits in a chaotic meandering jet flow
M. Yu. Uleysky; M. V. Budyansky; S. V. Prants
2007-12-25
We study the origin and bifurcations of typical classes of unstable periodic orbits in a jet flow that was introduced before as a kinematic model of chaotic advection, transport and mixing of passive scalars in meandering oceanic and atmospheric currents. A method to detect and locate the unstable periodic orbits and classify them by the origin and bifurcations is developed. We consider in detail period-1 and period-4 orbits playing an important role in chaotic advection. We introduce five classes of period-4 orbits: western and eastern ballistic ones, whose origin is associated with ballistic resonances of the fourth order, rotational ones, associated with rotational resonances of the second and fourth orders, and rotational-ballistic ones associated with a rotational-ballistic resonance. It is a new kind of nonlinear resonances that may occur in chaotic flow with jets and/or circulation cells. Varying the perturbation amplitude, we track out the origin and bifurcations of the orbits for each class.
Planar resonant periodic orbits in Kuiper belt dynamics
George Voyatzis; Thomas Kotoulas
2005-02-28
In the framework of the planar restricted three body problem we study a considerable number of resonances associated to the Kuiper Belt dynamics and located between 30 and 48 a.u. Our study is based on the computation of resonant periodic orbits and their stability. Stable periodic orbits are surrounded by regular librations in phase space and in such domains the capture of trans-Neptunian object is possible. All the periodic orbits found are symmetric and there is evidence for the existence of asymmetric ones only in few cases. In the present work first, second and third order resonances are under consideration. In the planar circular case we found that most of the periodic orbits are stable. The families of periodic orbits are temporarily interrupted by collisions but they continue up to relatively large values of the Jacobi constant and highly eccentric regular motion exists for all cases. In the elliptic problem and for a particular eccentricity value of the primary bodies the periodic orbits are isolated. The corresponding families, where they belong to, bifurcate from specific periodic orbits of the circular problem and seem to continue up to the rectilinear problem. Both stable and unstable orbits are obtained for each case. In the elliptic problem the unstable orbits found are associated with narrow chaotic domains in phase space. The evolution of the orbits, which are located in such chaotic domains, seems to be practically regular and bounded for long time intervals.
Enhanced entrainability of genetic oscillators by period mismatch
Yoshihiko Hasegawa; Masanori Arita
2013-01-12
Biological oscillators coordinate individual cellular components so that they function coherently and collectively. They are typically composed of multiple feedback loops, and period mismatch is unavoidable in biological implementations. We investigated the advantageous effect of this period mismatch in terms of a synchronization response to external stimuli. Specifically, we considered two fundamental models of genetic circuits: smooth- and relaxation oscillators. Using phase reduction and Floquet multipliers, we numerically analyzed their entrainability under different coupling strengths and period ratios. We found that a period mismatch induces better entrainment in both types of oscillator; the enhancement occurs in the vicinity of the bifurcation on their limit cycles. In the smooth oscillator, the optimal period ratio for the enhancement coincides with the experimentally observed ratio, which suggests biological exploitation of the period mismatch. Although the origin of multiple feedback loops is often explained as a passive mechanism to ensure robustness against perturbation, we study the active benefits of the period mismatch, which include increasing the efficiency of the genetic oscillators. Our findings show a qualitatively different perspective for both the inherent advantages of multiple loops and their essentiality.
Development of Seismic Isolation Systems Using Periodic Materials
Yan, Yiqun; Mo, Yi-Lung; Menq, Farn-Yuh; Stokoe, II, Kenneth H.; Perkins, Judy; Tang, Yu
2014-12-10
Advanced fast nuclear power plants and small modular fast reactors are composed of thin-walled structures such as pipes; as a result, they do not have sufficient inherent strength to resist seismic loads. Seismic isolation, therefore, is an effective solution for mitigating earthquake hazards for these types of structures. Base isolation, on which numerous studies have been conducted, is a well-defined structure protection system against earthquakes. In conventional isolators, such as high-damping rubber bearings, lead-rubber bearings, and friction pendulum bearings, large relative displacements occur between upper structures and foundations. Only isolation in a horizontal direction is provided; these features are not desirable for the piping systems. The concept of periodic materials, based on the theory of solid-state physics, can be applied to earthquake engineering. The periodic material is a material that possesses distinct characteristics that prevent waves with certain frequencies from being transmitted through it; therefore, this material can be used in structural foundations to block unwanted seismic waves with certain frequencies. The frequency band of periodic material that can filter out waves is called the band gap, and the structural foundation made of periodic material is referred to as the periodic foundation. The design of a nuclear power plant, therefore, can be unified around the desirable feature of a periodic foundation, while the continuous maintenance of the structure is not needed. In this research project, three different types of periodic foundations were studied: one-dimensional, two-dimensional, and three-dimensional. The basic theories of periodic foundations are introduced first to find the band gaps; then the finite element methods are used, to perform parametric analysis, and obtain attenuation zones; finally, experimental programs are conducted, and the test data are analyzed to verify the theory. This procedure shows that the periodic foundation is a promising and effective way to mitigate structural damage caused by earthquake excitation.
Evolution of the periodicities in 2S 0114+650
Ravi Sood; Sean Farrell; Paul O'Neill; Ravi Manchanda; N. M. Ashok
2006-03-01
We have analysed nine years of data from the All Sky Monitor on the Rossi X-ray Timing Explorer for 2S 0114+650 to study the evolution of its spin, binary and super-orbital periods. The spin history of the neutron star in this system exhibits torque reversals lasting ~1 yr. The newly discovered super-orbital period has remained stable over the 9-yr span, making 2S 0114+650 the fourth known system to exhibit stable super-orbital modulation. We compare its super-orbital period evolution with those of the other three such systems.
Fourier Analysis and Autocorrelation Function Applied to Periodical Nanostructures
Rockett, Angus
Fourier Analysis and Autocorrelation Function Applied to Periodical Nanostructures E. Cruz Microscopy (AFM) Image Fast Fourier Transformation Autocorrelation Function(AC) Angular Distribution] Fourier Analysis: analytical and geometrical aspects, Bray William O ed. New York: Marcel Dekker, 1994
Period tripling accumulation point for complexified Henon map
O. B. Isaeva; S. P. Kuznetsov
2005-09-06
Accumulation point of period-tripling bifurcations for complexified Henon map is found. Universal scaling properties of parameter space and Fourier spectrum intrinsic to this critical point is demonstrated.
Single-valued periods and multiple zeta values
Francis Brown
2013-09-20
The values at 1 of single-valued multiple polylogarithms span a certain subalgebra of multiple zeta values. In this paper, the properties of this algebra are studied from the point of view of motivic periods.
Competitive Multi-period Pricing with Fixed Inventories
Perakis, Georgia
This paper studies the problem of multi-period pricing for perishable products in a competitive (oligopolistic) market. We study non cooperative Nash equilibrium policies for sellers. At the beginning of the time horizon, ...
Generalized Cost Function Based Forecasting for Periodically Measured Nonstationary Traffic
Zeng, Yong - Department of Mathematics and Statistics, University of Missouri
1 Generalized Cost Function Based Forecasting for Periodically Measured Nonstationary Traffic true value. However, such a forecast- ing function is not directly applicable for applications potentially result in insufficient allocation of bandwidth leading to short term data loss. To facilitate
Neutron-Scattering Evidence for a Periodically Modulated Superconducti...
Office of Scientific and Technical Information (OSTI)
Neutron-Scattering Evidence for a Periodically Modulated Superconducting Phase in the Underdoped Cuprate La1.905Ba0.095CuO4 Citation Details In-Document Search Title:...
Dispersion extraction with near-field measurements in periodic waveguides
, R. D. Meade, and J. N. Winn, Photonic Crystals: Molding the Flow of Light (Princeton University. Joannopoulos, "Guided and defect modes in periodic dielectric wave-guides," J. Opt. Soc. Am. B 12, 1267
Linear Scaling Electronic Structure Methods with Periodic Boundary Conditions
Gustavo E. Scuseria
2008-02-08
The methodological development and computational implementation of linear scaling quantum chemistry methods for the accurate calculation of electronic structure and properties of periodic systems (solids, surfaces, and polymers) and their application to chemical problems of DOE relevance.
Real-time Multi-period truckload routing problems
Limpaitoon, Tanachai
2008-01-01
In this thesis we consider a multi-period truckload pick-up and delivery problem dealing with real-time requests over a finite time horizon. We introduce the notion of postponement of requests, whereby the company can ...
No more periods? Oral contraception and menstrual suppression
Gunson, Dr Jessie
Oral contraception, or ‘The Pill’, is widely used by women to control how often they have a period. In many countries using oral contraception in this way has remained unofficial practice. However, in 2003 the first FDA ...
Transport and Fractionation in Periodic Potential-Energy Landscapes
Kosta Ladavac; Matthew Pelton; David G. Grier
2004-04-09
Objects driven through periodically modulated potential-energy landscapes in two dimensions can become locked in to symmetry-selected directions that are independent of the driving force's orientation. We investigate this problem in the overdamped limit, and demonstrate that the crossover from free-flowing to locked-in transport can depend exponentially on an object's size, with this exceptional selectivity emerging from the periodicity of the environment.
Modal Approach to Casimir Forces in Periodic Structures
P. S. Davids; F. Intravaia; F. S. S. Rosa; D. A. R. Dalvit
2010-08-20
We present a modal approach to calculate finite temperature Casimir interactions between two periodically modulated surfaces. The scattering formula is used and the reflection matrices of the patterned surfaces are calculated decomposing the electromagnetic field into the natural modes of the structures. The Casimir force gradient from a deeply etched silicon grating is evaluated using the modal approach and compared to experiment for validation. The Casimir force from a two dimensional periodic structure is computed and deviations from the proximity force approximation examined.
Experimental continuation of periodic orbits through a fold
J. Sieber; A. Gonzalez-Buelga; S. A. Neild; D. J. Wagg; B. Krauskopf
2008-06-12
We present a continuation method that enables one to track or continue branches of periodic orbits directly in an experiment when a parameter is changed. A control-based setup in combination with Newton iterations ensures that the periodic orbit can be continued even when it is unstable. This is demonstrated with the continuation of initially stable rotations of a vertically forced pendulum experiment through a fold bifurcation to find the unstable part of the branch.
Time-Periodic Solutions of the Einstein's Field Equations II
De-Xing Kong; Kefeng Liu; Ming Shen
2008-07-31
In this paper, we construct several kinds of new time-periodic solutions of the vacuum Einstein's field equations whose Riemann curvature tensors vanish, keep finite or take the infinity at some points in these space-times, respectively. The singularities of these new time-periodic solutions are investigated and some new physical phenomena are found. The applications of these solutions in modern cosmology and general relativity can be expected.
An Autonomous Adaptive Scheduling Agent for Period Searching
Eric S. Saunders; Tim Naylor; Alasdair Allan
2008-01-24
We describe the design and implementation of an autonomous adaptive software agent that addresses the practical problem of observing undersampled, periodic, time-varying phenomena using a network of HTN-compliant robotic telescopes. The algorithm governing the behaviour of the agent uses an optimal geometric sampling technique to cover the period range of interest, but additionally implements proactive behaviour that maximises the optimality of the dataset in the face of an uncertain and changing operating environment.
Long period fiber gratings induced by mechanical resonance
Shahal, Shir; Duadi, Hamootal; Fridman, Moti
2015-01-01
We present a simple, and robust method for writing long period fiber gratings with low polarization dependent losses. Our method is based on utilizing mechanical vibrations of the tapered fiber while pooling it. Our method enables real-time tunability of the periodicity, efficiency and length of the grating. We also demonstrate complex grating by writing multiple gratings simultaneously. Finally, we utilized the formation of the gratings in different fiber diameters to investigate the Young's modulus of the fiber.
Time-periodic solutions of the Benjamin-Ono equation
Ambrose , D.M.; Wilkening, Jon
2008-04-01
We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations.
1D periodic potentials with gaps vanishing at k=0
O. Zagordi; A. Michelangeli
2008-10-13
Appearance of energy bands and gaps in the dispersion relations of a periodic potential is a standard feature of Quantum Mechanics. We investigate the class of one-dimensional periodic potentials for which all gaps vanish at the center of the Brillouin zone. We characterize them through a necessary and sufficient condition. Potentials of the form we focus on arise in different fields of Physics, from supersymmetric Quantum Mechanics, to Korteweg-de Vries equation theory and classical diffusion problems. The O.D.E. counterpart to this problem is the characterisation of periodic potentials for which coexistence occur of linearly independent solutions of the corresponding Schroedinger equation (Hill's equation). This result is placed in perspective of the previous related results available in the literature.
National Weatherization Assistance Program Characterization Describing the Recovery Act Period
Tonn, Bruce Edward; Rose, Erin M.; Hawkins, Beth A.
2015-10-01
This report characterizes the U.S. Department of Energy s Weatherization Assistance Program (WAP) during the American Recovery and Reinvestment Act of 2009 (Recovery Act) period. This research was one component of the Recovery Act evaluation of WAP. The report presents the results of surveys administered to Grantees (i.e., state weatherization offices) and Subgrantees (i.e., local weatherization agencies). The report also documents the ramp up and ramp down of weatherization production and direct employment during the Recovery Act period and other challenges faced by the Grantees and Subgrantees during this period. Program operations during the Recovery Act (Program Year 2010) are compared to operations during the year previous to the Recovery Act (Program Year 2008).
Lyapunov functions for periodic matrix-valued Jacobi operators
Evgeny Korotyaev; Anton Kutsenko
2007-01-16
We consider periodic matrix-valued Jacobi operators. The spectrum of this operator is absolutely continuous and consists of intervals separated by gaps. We define the Lyapunov function, which is analytic on an associated Riemann surface. On each sheet the Lyapunov function has the standard properties of the Lyapunov function for the scalar case. We show that this function has (real or complex) branch points, which we call resonances. We prove that there exist two types of gaps: i) stable gaps, i.e., the endpoints are periodic and anti-periodic eigenvalues, ii) unstable (resonance) gaps, i.e., the endpoints are resonances (real branch points). We show that some spectral data determine the spectrum (counting multiplicity) of the Jacobi operator.
Periodic Discrete Energy for Long-Range Potentials
D. P. Hardin; E. B. Saff; Brian Simanek
2014-12-11
We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.
High Efficiency Electron-Laser Interactions in Tapered Helical Undulators
Duris, Joseph
2015-01-01
Demonstration of high-trapping efficiency and narrow energylaser accelerator for efficient production of high qualityand J. S. Wurtele. High-efficiency extraction of microwave
UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC
Bakeman, M.S.
2010-01-01
LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC* M.S.quasi-monoenergetic electron beams with energies up to 1high-peak- current, electron beams are ideal for driving a
Lateral undulation of a snake-like robot
Gupta, Amit
2007-01-01
Snake robots have been studied by many researchers but historically more on a theoretical basis. Recently, more and more robotic snakes have been realized in hardware. This thesis presents a design process for the electrical, ...
Undulator-based production of polarized positrons$ G. Alexander j
McDonald, Kirk
as the International Linear Collider, ILC [1] and the Compact Linear Collider, CLIC [2]) will require the development
Knot Undulator to Generate Linearly Polarized Photons with Low...
Office of Scientific and Technical Information (OSTI)
Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for pages...
Point Vortices: Finding Periodic Orbits and their Topological Classification
Spencer A. Smith
2015-10-22
The motion of point vortices constitutes an especially simple class of solutions to Euler's equation for two dimensional, inviscid, incompressible, and irrotational fluids. In addition to their intrinsic mathematical importance, these solutions are also physically relevant. Rotating superfluid helium can support rectilinear quantized line vortices, which in certain regimes are accurately modeled by point vortices. Depending on the number of vortices, it is possible to have either regular integrable motion or chaotic motion. Thus, the point vortex model is one of the simplest and most tractable fluid models which exhibits some of the attributes of weak turbulence. The primary aim of this work is to find and classify periodic orbits, a special class of solutions to the point vortex problem. To achieve this goal, we introduce a number of algorithms: Lie transforms which ensure that the equations of motion are accurately solved; constrained optimization which reduces close return orbits to true periodic orbits; object-oriented representations of the braid group which allow for the topological comparison of periodic orbits. By applying these ideas, we accumulate a large data set of periodic orbits and their associated attributes. To render this set tractable, we introduce a topological classification scheme based on a natural decomposition of mapping classes. Finally, we consider some of the intriguing patterns which emerge in the distribution of periodic orbits in phase space. Perhaps the most enduring theme which arises from this investigation is the interplay between topology and geometry. The topological properties of a periodic orbit will often force it to have certain geometric properties.
Periodic homogenization and material symmetry in linear elasticity
Mariya Ptashnyk; Brian Seguin
2015-05-07
Here homogenization theory is used to establish a connection between the symmetries of a periodic elastic structure associated with the microscopic properties of an elastic material and the material symmetries of the effective, macroscopic elasticity tensor. Previous results of this type exist but here more general symmetries on the microscale are considered. Using an explicit example, we show that it is possible for a material to be fully anisotropic on the microscale and yet have a nontrivial material symmetry group on the macroscale. Another example demonstrates that not all material symmetries of the macroscopic elastic tensor are generated by symmetries of the periodic elastic structure.
Self-organized periodicity of protein clusters in growing bacteria
Hui Wang; Ned S. Wingreen; Ranjan Mukhopadhyay
2008-08-06
Chemotaxis receptors in E. coli form clusters at the cell poles and also laterally along the cell body, and this clustering plays an important role in signal transduction. Recently, experiments using flourrescence imaging have shown that, during cell growth, lateral clusters form at positions approximately periodically spaced along the cell body. In this paper, we demonstrate within a lattice model that such spatial organization could arise spontaneously from a stochastic nucleation mechanism. The same mechanism may explain the recent observation of periodic aggregates of misfolded proteins in E. coli.
Periodic Photometric Variability in the Becklin-Neugebauer Object
Lynne A. Hillenbrand; John M. Carpenter; M. F. Skrutskie
2000-10-24
The Becklin-Neugebauer (BN) object in the Orion Nebula Cluster (ONC) is a well-studied optically invisible, infrared-bright young stellar object, thought to be an intermediate-mass protostar. We report here that BN exhibited nearly-sinusoidal periodic variability at the near-infrared H- and Ks-bands during a one month observing campaign in 2000 March/April. The period was 8.28 days and the peak-to-peak amplitude ~0.2 mag. Plausible mechanisms for producing the observed variability characteristics are explored.
Period doubling, information entropy, and estimates for Feigenbaum's constants
Reginald D. Smith
2013-08-03
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.
Producingapowerfullaserbeambyusing antimatter and `sequeezing' exotic
Uggerhøj, Ulrik I.
) Web: http://www.cordis.lu/nest PECU NEST ADVENTURE The micro-undulator is periodically `bent' crystalProducingapowerfullaserbeambyusing antimatter and `sequeezing' exotic crystals might sound like on the properties of a class of materials called crystaline undulators. These are periodically deformed crystals
Proton aurora related to intervals of pulsations of diminishing periods
California at Berkeley, University of
Proton aurora related to intervals of pulsations of diminishing periods A. G. Yahnin,1 T. A are generated because of a cyclotron instability of the anisotropic distribution of ring current ions. Proton precipitation produced by the cyclotron instability can be responsible for proton aurora. Indeed
Quasi-bound states in periodically driven scattering
H. Landa
2015-06-29
We present an approach for obtaining eigenfunctions of periodically driven time-dependent Hamiltonians. Assuming an approximate scale separation between two spatial regions where different potentials dominate, we derive an explicit expansion for scattering problems with mixed cylindrical and spherical symmetry, by matching wavefunctions of a periodic linear drive in the exterior region to solutions of an arbitrary interior potential expanded in spherical waves. Using this method we study quasi-bound states of a square-well potential in three dimensions subject to an axial driving force. In the nonperturbative regime we show how eigenfunctions develop an asymptotic dressing of different partial waves, accompanied by large periodic oscillations in the angular momentum and a nonmonotonous dependence of the decay rate on the drive strength. We extend these results to the strong driving regime near a resonant intersection of the quasi-energy surfaces of two bound states of different symmetry. Our approach can be applied to general quantum scattering problems of particles subject to periodic fields.
Emergence of spike correlations in periodically forced excitable systems
Jose A. Reinoso; M. C. Torrent; Cristina Masoller
2015-10-30
In sensory neurons the presence of noise can facilitate the detection of weak information-carrying signals, which are encoded and transmitted via correlated sequences of spikes. Here we investigate relative temporal order in spike sequences induced by a subthreshold periodic input, in the presence of white Gaussian noise. To simulate the spikes, we use the FitzHugh-Nagumo model, and to investigate the output sequence of inter-spike intervals (ISIs), we use the symbolic method of ordinal analysis. We find different types of relative temporal order, in the form of preferred ordinal patterns which depend on both, the strength of the noise and the period of the input signal. We also demonstrate a resonance-like behavior, as certain periods and noise levels enhance temporal ordering in the ISI sequence, maximizing the probability of the preferred patterns. Our findings could be relevant for understanding the mechanisms underlying temporal coding, by which single sensory neurons represent in spike sequences the information about weak periodic stimuli.
Periodic bedrock ridges on Mars David R. Montgomery,1
Montgomery, David R.
Periodic bedrock ridges on Mars David R. Montgomery,1 Joshua L. Bandfield,1 and Scott K. Becker1 to be widespread [Carr, 1981; Greeley et al., 1992; Malin and Edgett, 2001]. Although wind-streamlined yardangs interpreted as sedimentary forms [McCauley et al., 1972; Cutts and Smith, 1973; Carr, 1981; Greeley et al
Particle energization through time-periodic helical magnetic fields
Mitra, Dhrubaditya
We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show ...
Periodic fluctuations in deep water formation due to sea ice
Raj Saha
2015-02-21
During the last ice age several quasi-periodic abrupt warming events took place. Known as Dansgaard-Oeschger (DO) events their effects were felt globally, although the North Atlantic experienced the largest temperature anomalies. Paleoclimate data shows that the fluctuations often occurred right after massive glacial meltwater releases in the North Atlantic and in bursts of three or four with progressively decreasing strengths. In this study a simple dynamical model of an overturning circulation and sea ice is developed with the goal of understanding the fundamental mechanisms that could have caused the DO events. Interaction between sea ice and the overturning circulation in the model produces self-sustained oscillations. Analysis and numerical experiments reveal that the insulating effect of sea ice causes the ocean to periodically vent out accumulated heat in the deep ocean into the atmosphere. Subjecting the model to idealized freshwater forcing mimicking Heinrich events causes modulation of the natural periodicity and produces burst patterns very similar to what is observed in temperature proxy data. Numerical experiments with the model also suggests that the characteristic period of 1,500 years is due to the geometry, or the effective heat capacity, of the ocean that comes under sea ice cover.
Passive Tracer Dispersion with Random or Periodic Source \\Lambda
Passive Tracer Dispersion with Random or Periodic Source \\Lambda Jinqiao Duan Clemson University sources on the pattern formation and longÂtime behavior of concentration proÂ files of passive tracers Introduction The dispersion of passive tracers (or passive scalars) occur in various geoÂ physical
Passive Tracer Dispersion with Random or Periodic Source
Passive Tracer Dispersion with Random or Periodic Source Jinqiao Duan Clemson University sources on the pattern formation and long-time behavior of concentration pro- #12;les of passive tracers #12;1 Introduction The dispersion of passive tracers (or passive scalars) occur in various geo
Greedy Approaches to Static Stochastic Robust Resource Allocation for Periodic
Maciejewski, Anthony A.
Greedy Approaches to Static Stochastic Robust Resource Allocation for Periodic Sensor Driven@us.ibm.com Abstract-- This research investigates the problem of robust resource allocation for a large class. Such systems are expected to function in an environment replete with uncertainty where the workload is likely
lthough Earth has undergone many periods of significant environmen-
Horton, Tom
A lthough Earth has undergone many periods of significant environmen- tal change, the planet push the Earth system outside the stable environmental state of the Holocene, with consequences occurred naturally and Earth's regu- latory capacity maintained the conditions that enabled human
The Chinese Calendar of The Later Han Period
Aslaksen, Helmer
The Chinese Calendar of The Later Han Period Undergraduate Research Opportunities Programme would like to learn some basic knowledge in the Chinese calendar, which is an important part of the Chinese culture and Chinese history. However, by the time we decided to take this project, the deadline
Temperature-induced marine export production during glacial period
Chikamoto, Megumi O.
Temperature-induced marine export production during glacial period M. O. Chikamoto,1,2 A. Abe October 2012; published 8 November 2012. [1] Proxy records indicate that export production was enhanced at the onset of the last glaciation. We examine how glacial cooling affects marine export production through
Bifurcation and Stability Properties of Periodic Solutions to Two Nonlinear
Fiedler, Bernold
motions of suspension bridges. Though they were able to replicate the phenomena observed on the Tacoma in suspen- sion bridges. We contrast the multiplicity, bifurcation, and stability of periodic solutions-doubling and quadrupling) differs significantly. Keywords: suspension bridge, continuation, bifurcation, stability
Urban Water Demand with Periodic Error Correction David R. Bell
Griffin, Ronald
them. Econometric estimates of residential demand for water abound (Dalhuisen et al. 2003Urban Water Demand with Periodic Error Correction by David R. Bell and Ronald C. Griffin February, Department of Agricultural Economics, Texas A&M University. #12;Abstract Monthly demand for publicly supplied
RIEMANN SURFACES, PLANE ALGEBRAIC CURVES AND THEIR PERIOD MATRICES
numerically the canonical map. Therefore symmetric 1991 Mathematics Subject Classification. 14Q05, 14H55, 14P for computing a representation of a compact Riemann surface as an algebraic plane curve and to compute a numerical approximation for its period matrix. We will describe a program Cars ([3]) that can be used
Numerical Modeling of Periodic Composite Media for Electromagnetic Shielding Application
Koledintseva, Marina Y.
on a conventional mixing theory, have served as the fundamentals for these techniques. In these formulationsNumerical Modeling of Periodic Composite Media for Electromagnetic Shielding Application Dagang Wu-difference time-domain (FDTD) method. The results are compared with conventional mixing theories and 3D Fourier
Oscillations with uniquely long periods in a microfluidic bubble generator
Loss, Daniel
LETTERS Oscillations with uniquely long periods in a microfluidic bubble generator PIOTR GARSTECKI1 generator that shows stable oscillatory patterns (both in space and time) of unanticipated complexity to a single outlet channel. In this geometry, the pinch-off process that generates bubbles is regulated17
Marchenko-Ostrovski mappings for periodic Jacobi matrices
Evgeny Korotyaev; Anton Kutsenko
2007-10-15
We consider the 1D periodic Jacobi matrices. The spectrum of this operator is purely absolutely continuous and consists of intervals separated by gaps. We solve the inverse problem (including characterization) in terms of vertical slits on the quasimomentum domain . Furthermore, we obtain a priori two-sided estimates for vertical slits in terms of Jacoby matrices.
Local Lyapunov Functions for periodic and finite-time ODEs
Hafstein, Sigurður Freyr
Local Lyapunov Functions for periodic and finite-time ODEs Peter Giesl and Sigurdur Hafstein Abstract Lyapunov functions for general systems are difficult to construct. How- ever, for autonomous Lyapunov function by solving a matrix equa- tion. Consequently, the same function is a local Lyapunov
Strategic Sourcing Dashboard Reporting Period: January 2010 through December 2011
Minnesota, University of
We have accomplished $10.8 million in annual savings through our Strategic Sourcing efforts over below. Strategic Sourcing continues to have a significant emphasis for Purchasing Services, but savings/Activities/Risks for this Reporting Period Annual savings of over $200,000 was booked in the last quarter in the office and lab supply
NANO EXPRESS Fabrication of Large Area Periodic Nanostructures Using
Mohseni, Hooman
, such as photonic band-gap materials, high dense data storage, and photonic devices. We have developed a maskless areas, such as photonic band-gap materials [1], high dense data storage [2], and photonic devices [3NANO EXPRESS Fabrication of Large Area Periodic Nanostructures Using Nanosphere Photolithography
Total Estimated Contract Cost: Contract Option Period: Performance
Office of Environmental Management (EM)
Performance Period Fee Earned FY2000 thru 2008 102,622,325 FY2009 12,259,719 FY2010 35,789,418 FY2011 24,126,240 FY2012 24,995,209 FY2013 6,340,762 FY2014 16,285,867 FY2015...
EE 511 Solutions to Problem Set 8 1. E[Yt] = E[Xt] cos 2fct. E[Yt] is periodic with period 1/fc.
Bhashyam, Srikrishna
EE 511 Solutions to Problem Set 8 1. E[Yt] = E[Xt] cos 2fct. E[Yt] is periodic with period 1/fc. RY (t, t + ) = E[Xt+ cos 2fc(t + )Xt cos 2fct] = RX() 2 [cos 2fc + cos 2fc(2t + )] RY (t, t + ) is periodic with period 1/(2fc). Therefore, Yt is wide-sense cyclostationary with period 1/fc. E[Zt] = E[Xt]E[cos
IRC-10443: a multi-periodic SRa variable and the nature of long secondary periods in AGB stars
U. Munari; A. Siviero; P. Ochner; S. Dallaporta; C. Simoncelli
2008-10-08
We obtained BVIc photometry of IRC-10443 on 85 different nights distributed over two years, and in addition low resolution absolute spectro- photometry and high resolution Echelle spectroscopy. Our data show that IRC-10443, which was never studied before in any detail, is a SRa variable, characterized by Delta(B)=1.27, Delta(V)=1.14 and Delta(I)=0.70 mag amplitudes and mean values =13.75, =11.33 and =6.18 mag. Two strong periodicities are simultaneously present: a principal one of 85.5 (+/-0.2) days, and a secondary one of 620 (+/-15) days, both sinusoidal in shape, and with semi-amplitudes Delta(V)=0.41 and 0.20 mag, respectively. IRC-10443 turns out to be a M7III star, with a mean heliocentric radial velocity -28 km/s and reddened by E(B-V)=0.87, a third of which of circumstellar origin. The same 0.5 kpc distance is derived from application of the appropriate period-luminosity relations to both the principal and the secondary periods. The long secondary period causes a sinusoidal variation in color of 0.13 mag semi-amplitude in V-Ic, with IRC-10443 being bluest at maximum and reddest at minimum, and with associated changes in effective temperature and radius of 85 K and 6%, respectively. This behavior of colors argues in favor of a pulsation nature for the still mysterious long secondary periods in AGB stars.
Particle energization through time-periodic helical magnetic fields
Mitra, Dhrubaditya; Dasgupta, Brahmananda; Niklasson, Eyvind; Ram, Abhay
2013-01-01
We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with $A=B=C=1$ are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late time with positive Lyapunov exponent. We further show that in time-periodic (frequency $\\omega$) ABC fields the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with exponent $\\xi$ that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the PDF of kinetic energy is, at late time, close to a Gaussian but with steeper tails.
Particle energization through time-periodic helical magnetic fields
Dhrubaditya Mitra; Axel Brandenburg; Brahmananda Dasgupta; Eyvind Niklasson; Abhay Ram
2014-04-30
We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients $A=B=C=1$ are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late times with positive Lyapunov exponent. We further show that in time-periodic ABC fields, the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with an exponent that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the PDF of kinetic energy is, at late times, close to a Gaussian but with steeper tails.
Parameters of Integral Circulant Graphs and Periodic Quantum Dynamics
Nitin Saxena; Simone Severini; Igor Shparlinski
2007-03-26
The intention of the paper is to move a step towards a classification of network topologies that exhibit periodic quantum dynamics. We show that the evolution of a quantum system, whose hamiltonian is identical to the adjacency matrix of a circulant graph, is periodic if and only if all eigenvalues of the graph are integers (that is, the graph is integral). Motivated by this observation, we focus on relevant properties of integral circulant graphs. Specifically, we bound the number of vertices of integral circulant graphs in terms of their degree, characterize bipartiteness and give exact bounds for their diameter. Additionally, we prove that circulant graphs with odd order do not allow perfect state transfer.
Periodic fluctuations in deep water formation due to sea ice
Saha, Raj
2015-01-01
During the last ice age several quasi-periodic abrupt warming events took place. Known as Dansgaard-Oeschger (DO) events their effects were felt globally, although the North Atlantic experienced the largest temperature anomalies. Paleoclimate data shows that the fluctuations often occurred right after massive glacial meltwater releases in the North Atlantic and in bursts of three or four with progressively decreasing strengths. In this study a simple dynamical model of an overturning circulation and sea ice is developed with the goal of understanding the fundamental mechanisms that could have caused the DO events. Interaction between sea ice and the overturning circulation in the model produces self-sustained oscillations. Analysis and numerical experiments reveal that the insulating effect of sea ice causes the ocean to periodically vent out accumulated heat in the deep ocean into the atmosphere. Subjecting the model to idealized freshwater forcing mimicking Heinrich events causes modulation of the natural p...
Periodic Schrödinger operators with local defects and spectral pollution
Eric Cancès; Virginie Ehrlacher; Yvon Maday
2011-11-16
This article deals with the numerical calculation of eigenvalues of perturbed periodic Schr\\"odinger operators located in spectral gaps. Such operators are encountered in the modeling of the electronic structure of crystals with local defects, and of photonic crystals. The usual finite element Galerkin approximation is known to give rise to spectral pollution. In this article, we give a precise description of the corresponding spurious states. We then prove that the supercell model does not produce spectral pollution. Lastly, we extend results by Lewin and S\\'er\\'e on some no-pollution criteria. In particular, we prove that using approximate spectral projectors enables one to eliminate spectral pollution in a given spectral gap of the reference periodic Sch\\"odinger operator.
Inverse design of periodic metallic slits for extraordinary optical transmission
Deng, Yongbo; Liu, Zhenyu; Wu, Yihui
2016-01-01
The inverse design methodology of periodic metallic slits for extraordinary optical transmission is presented based on the topology optimization method. Several topological configurations of periodic metallic slits with typical subwavelength size are derived with transmission peaks at the prescribed incident wavelengths in the visible light region, where the transmissivity is enhanced by effective excitation of surface-plasmon-polariton at the inlet side of the slit, Fabry-P\\'erot resonance of surface-plasmon-polariton inside the slit and radiation of the electromagnetic energy at the outlet side of the slit. The transmission peaks of the derived metallic configurations are raised along with the red shift of the incident wavelength, because of the reduction of the energy absorption and increase of the propagation distance of surface-plasmon-polariton. And the shift of transmission peak is controlled by prescribing a different incident wavelength in the corresponding topology optimization problem. To reduce th...
Period change and stellar evolution of $\\beta$ Cephei stars
Neilson, Hilding R
2015-01-01
The $\\beta$ Cephei stars represent an important class of massive star pulsators probing the evolution of B-type stars and the transition from main sequence to hydrogen-shell burning evolution. By understanding $\\beta$ Cep stars, we gain insights into the detailed physics of massive star evolution such as rotational mixing, convective core overshooting, magnetic fields and stellar winds, all of which play important roles. Similarly, modeling their pulsation provides additional information into their interior structures. Furthermore, measurements of the rate of change of pulsation period offer a direct measure of $\\beta$ Cephei stellar evolution. In this work, we compute state-of-the-art stellar evolution models assuming different amounts of initial rotation and convective core overshoot and measure theoretical rates of period change for which we compare to rates previously measured for a sample of $\\beta$ Cephei stars. The results of this comparison are mixed. For three stars, the rates are too small to infer ...
Quasi-periodic quantum dot arrays produced by electrochemical synthesis
Bandyopadhyay, S.; Miller, A.E.; Yue, D.F.; Banerjee, G.; Ricker, R.E.; Jones, S.; Eastman, J.A.; Baugher, E.; Chandrasekhar, M.
1994-06-01
We discuss a ``gentle`` electrochemical technique for fabricating quasi-periodic quantum dot arrays. The technique exploits a self-organizing phenomenon to produce quasi-periodic arrangement of dots and provides excellent control over dot size and interdot spacing. Unlike conventional nanolithography, it does not cause radiation damage to the structures during exposure to pattern delineating beams (e-beam, ion-beam or x-ray). Moreover, it does not require harsh processing steps like reactive ion etching, offers a minimum feature size of {approximately}40 {angstrom}, allows the fabrication of structures on nonplanar surfaces (e.g. spherical or cylindrical substrates), is amenable to mass production (millions of wafers can be processed simultaneously) and is potentially orders of magnitude cheaper than conventional nanofabrication. In this paper, we describe our initial results and show the promise of this technique for low-cost and high-yield nanosynthesis.
Period tripling causes rotating spirals in agitated wet granular layers
Kai Huang; Ingo Rehberg
2011-07-07
Pattern formation of a thin layer of vertically agitated wet granular matter is investigated experimentally. Rotating spirals with three arms, which correspond to the kinks between regions with different colliding phases, are the dominating pattern. This preferred number of arms corresponds to period tripling of the agitated granular layer, unlike predominantly subharmonic Faraday crispations in dry granular matter. The chirality of the spatiotemporal pattern corresponds to the rotation direction of the spirals.
Sorting by Periodic Potential Energy Landscapes: Optical Fractionation
Kosta Ladavac; Karen Kasza; David G. Grier
2003-10-16
Viscously damped objects driven through a periodically modulated potential energy landscape can become kinetically locked in to commensurate directions through the landscape, and thus can be deflected away from the driving direction. We demonstrate that the threshold for an object to become kinetically locked in to an array can depend exponentially on its size. When implemented with an array of holographic optical tweezers, this provides the basis for a continuous and continuously optimized sorting technique for mesoscopic objects called ``optical fractionation''.
EIS-0391: Notice to Extend Scoping Period | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based|Department of5Department ofto Extend Scoping Period EIS-0391: Notice to
Enforcement Policy Statement: Compliance Period for Regional Standards
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12, 2015 Infographiclighbulbs - high-resolution JPG20,1LLC |Compliance Period for
Magnetic field gradients in solar wind plasma and geophysics periods
A. Bershadskii
2006-11-16
Using recent data obtained by Advanced Composition Explorer (ACE) the pumping scale of the magnetic field gradients of the solar wind plasma has been calculated. This pumping scale is found to be equal to 24h $\\pm$ 2h. The ACE spacecraft orbits at the L1 libration point which is a point of Earth-Sun gravitational equilibrium about 1.5 million km from Earth. Since the Earth's magnetosphere extends into the vacuum of space from approximately 80 to 60,000 kilometers on the side toward the Sun the pumping scale cannot be a consequence of the 24h-period of the Earth's rotation. Vise versa, a speculation is suggested that for the very long time of the coexistence of Earth and of the solar wind the weak interaction between the solar wind and Earth could lead to stochastic synchronization between the Earth's rotation and the pumping scale of the solar wind magnetic field gradients. This synchronization could transform an original period of the Earth's rotation to the period close to the pumping scale of the solar wind magnetic field gradients.
Non-Foster Circuit Loaded Periodic Structures for Broadband Fast and Slow Wave Propagation
Long, Jiang
2015-01-01
1.1 Periodic Structure, Fast and Slow Wave Propagation . 1.2for a periodic structure. . . . . . . Slow and fast waveA unit cell of a periodic structure . . . . .
NASA-TM-III642 Design of Inielligent Mesoscale Periodic Array
Asher, Sanford A.
i" /} , NASA-TM-III642 Design of Inielligent Mesoscale Periodic Array Structures Utilizing Smart *National Research Council hitrodoetion Mesoscale Periodic Arlay Structures (MPAS, also known as crystalline
Beyond periodic orbits: An example in nonhydrogenic atoms
Dando, P.A.; Monteiro, T.S.; Delande, D.; Taylor, K.T. (Department of Mathematics, Royal Holloway, University of London, Egham, Surrey, TW20 0EX (United Kingdom) Laboratoire Kastler-Brossel, Universite Pierre et Marie Curie, 4 place Jussieu, F-75005 Paris (France) Department of Applied Mathematics and Theoretical Physics, Queen's University Belfast, Belfast, BT7 1NN (United Kingdom))
1995-02-13
The spectrum of hydrogen in a magnetic field is a paradigm of quantum chaos and may be analyzed accurately by periodic-orbit-type theories. In nonhydrogenic atoms, the core induces pure quantum effects, especially additional spectral modulations, which cannot be analyzed reliably in terms of classical orbits and their stability parameters. Provided core-scattered waves are included consistently, core-scattered modulations as well as corrected amplitudes for primitive orbits are in excellent agreement with quantum results. We consider whether these systems correspond to quantum chaos.
Bott-Kitaev Periodic Table and the Diagonal Map
R. Kennedy; M. R. Zirnbauer
2014-12-15
Building on the 10-way symmetry classification of disordered fermions, the authors have recently given a homotopy-theoretic proof of Kitaev's "Periodic Table" for topological insulators and superconductors. The present paper offers an introduction to the physical setting and the mathematical model used. Basic to the proof is the so-called Diagonal Map, a natural transformation akin to the Bott map of algebraic topology, which increases by one unit both the momentum-space dimension and the symmetry index of translation-invariant ground states of gapped free-fermion systems. This mapping is illustrated here with a few examples of interest.
PARC Periodical: Volume 5, Issue 3 | Photosynthetic Antenna Research Center
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access toOctoberConsumptionPowered oscillator usingLowPeriodical-Volume
Property:Building/StartPeriod | Open Energy Information
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 QA:QA J-E-1 SECTION J APPENDIXsourceIIInformationEnergy InformationInformation Total Jump to:StartPeriod
PULSATION PERIOD VARIATIONS IN THE RRc LYRAE STAR KIC 5520878
Hippke, Michael; Learned, John G.; Zee, A.; Edmondson, William H.; Lindner, John F.; Kia, Behnam; Ditto, William L.; Stevens, Ian R. E-mail: jgl@phys.hawaii.edu E-mail: w.h.edmondson@bham.ac.uk E-mail: wditto@hawaii.edu E-mail: irs@star.sr.bham.ac.uk
2015-01-01
Learned et al. proposed that a sufficiently advanced extra-terrestrial civilization may tickle Cepheid and RR Lyrae variable stars with a neutrino beam at the right time, thus causing them to trigger early and jogging the otherwise very regular phase of their expansion and contraction. This would turn these stars into beacons to transmit information throughout the galaxy and beyond. The idea is to search for signs of phase modulation (in the regime of short pulse duration) and patterns, which could be indicative of intentional, omnidirectional signaling. We have performed such a search among variable stars using photometric data from the Kepler space telescope. In the RRc Lyrae star KIC 5520878, we have found two such regimes of long and short pulse durations. The sequence of period lengths, expressed as time series data, is strongly autocorrelated, with correlation coefficients of prime numbers being significantly higher (p = 99.8%). Our analysis of this candidate star shows that the prime number oddity originates from two simultaneous pulsation periods and is likely of natural origin. Simple physical models elucidate the frequency content and asymmetries of the KIC 5520878 light curve. Despite this SETI null result, we encourage testing of other archival and future time-series photometry for signs of modulated stars. This can be done as a by-product to the standard analysis, and can even be partly automated.
Periodicity of the solar full-disk magnetic fields
Xiang, N. B.; Qu, Z. N.; Zhai, Q. [National Astronomical Observatories/Yunnan Observatory, CAS, Kunming 650011 (China)
2014-07-01
A full-disk solar magnetogram has been measured each day since 1970 January 19, and the daily Magnetic Plage Strength Index (MPSI) and the daily Mount Wilson Sunspot Index (MWSI) were calculated for each magnetogram at the Mount Wilson Observatory. The MPSI and MWSI are used to investigate the periodicity of the solar full-disk magnetic activity through autocorrelation analyses. Just two periods, the solar cycle and the rotation cycle, are determined in both the MPSI (the solar full-disk weak magnetic field activity) and MWSI (the solar full-disk strong magnetic field activity) with no annual signal found. The solar cycle for MPSI (10.83 yr) is found to be obviously longer than that for MWSI (9.77 yr). The rotation cycle is determined to be 26.8 ± 0.63 sidereal days for MPSI and 27.4 ± 2.4 sidereal days for MWSI. The rotation cycle length for MPSI is found to fluctuate around 27 days within a very small amplitude, but for MWSI it obviously temporally varies with a rather large amplitude. The rotation cycle for MWSI seems longer near solar minimum than at solar maximum. Cross-correlation analyses of daily MPSI and MWSI are carried out, and it is inferred that the MPSI components partly come from relatively early MWSI measurements.
Ferromagnetism in the two-dimensional periodic Anderson model
Batista, C. D.; Bonca, J.; Gubernatis, J. E.
2001-05-01
Using the constrained-path Monte Carlo method, we studied the magnetic properties of the two-dimensional periodic Anderson model for electron fillings between 1/4 and 1/2. We also derived two effective low-energy theories to assist in interpreting the numerical results. For 1/4 filling, we found that the system can be a Mott or a charge-transfer insulator, depending on the relative values of the Coulomb interaction and the charge-transfer gap between the two noninteracting bands. The insulator may be a paramagnet or antiferromagnet. We concentrated on the effect of electron doping on these insulating phases. Upon doping we obtained a partially saturated ferromagnetic phase for low concentrations of conduction electrons. If the system were a charge-transfer insulator, we would find that the ferromagnetism is induced by the well-known Ruderman-Kittel-Kasuya-Yosida interaction. However, we found a novel correlated hopping mechanism inducing the ferromagnetism in the region where the nondoped system is a Mott insulator. Our regions of ferromagnetism spanned a much smaller doping range than suggested by recent slave boson and dynamical mean-field theory calculations, but they were consistent with that obtained by density-matrix renormalization group calculations of the one-dimensional periodic Anderson model.
Broader source: Energy.gov [DOE]
Energy Conservation Program for Consumer Products: Test Procedures for Furnaces and Boilers, Comment Period Extension
TESLA-FEL 2004-02 The Potential for the Development of the
TESLA-FEL 2004-02 The Potential for the Development of the X-Ray Free Electron Laser E.L. Saldin, E Abstract X-ray photon beam from a SASE FEL undulator is in principle a single user tool, just like the SASE FEL with three undulators which have different period and tunable gap. All electrons
Variable Selection and Inference for Multi-period Forecasting Problems
Pesaran, M Hashem; Pick, Andreas; Timmermann, Allan
?t,x?t)?. Multi-period forecasts of yt can then be obtained iteratively using a conventional VAR of the form zt = µz + ( Ap(L) Bq(L) Cr(L) Ds(L) ) zt?1 + ?t, (10) where p and q are the lag order of yt and xt in the equation for yt and r and s is the lag order... , i.e. Cr(L) and Bq(L) in particular. To deal with this issue, a conditional factor-augmentation approach can be used. In this approach, the large-dimensional xt-vector is condensed into a subset of factors, fˆ t, of dimension m < M , used to summarize...
Transverse commensurability effect for vortices on periodic pinning arrays
Reichhardt, Charles; Reichhardt, Cynthia J
2008-01-01
Using computer simulations, we demonstrate a type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.
Chaotic dynamics in a periodically driven spin-1 condensate
Cheng Jing [Department of Physics, South China University of Technology, Guangzhou 510640 (China); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China)
2010-02-15
We use periodically modulated magnetic fields to drive spin-1 Bose-Einstein condensates (BECs) and study the corresponding spin-mixing dynamics. Due to the time-dependent driving, this system permits chaotic dynamics depending on the drive parameters, which could not occur in previous studies. From the investigation of the Poincare sections, we find there exist complex trajectories in the phase space, leading to very complicated structures of the phase space with mixed regular and chaotic regions. By calculating the quasienergy levels of the corresponding Floquet operators, the signatures of quantum chaos are also found in this system. The level spacing distribution is very close to the Poisson distribution or Wigner distribution when the corresponding classical dynamics is regular or chaotic.
Quasi-periodic oscillations from relativistic hydrodynamical slender tori
Mishra, B; Manousakis, A; Fragile, P C; Paumard, T; Klu?niak, W
2015-01-01
We simulate an oscillating purely hydrodynamical torus with constant specific angular mo- mentum around a Schwarzschild black hole. The goal is to search for quasi-periodic oscil- lations (QPOs) in the light curve of the torus. The initial torus setup is subjected to radial, vertical and diagonal (combination of radial and vertical) velocity perturbations. The hydro- dynamical simulations are performed using the general relativistic magnetohydrodynamics code Cosmos++ and ray-traced using the GYOTO code. We found that a horizontal velocity perturbation triggers the radial and plus modes, while a vertical velocity perturbation trig- gers the vertical and X modes. The diagonal perturbation gives a combination of the modes triggered in the radial and vertical perturbations.
Instrumentation to Monitor Transient Developing Periodic Flow in Newtonian Slurries
Bamberger, Judith A.; Enderlin, Carl W.
2014-08-03
This paper describes measurement techniques developed and applied to characterize solids mobilization and mixing of Newtonian slurries that are subjected to transient, periodic, developing flows. Metrics to characterize mobilization and mixing are the just suspended velocity (UJS) and the cloud height (HC). Two ultrasonic instruments to characterize pulse jet mixing of slurries were developed and deployed to measure related metrics: the thickness of the settled bed (used to determine mobilization) and the concentration within the cloud as a function of elevation [C(Z)]. A second method, continuous sample extraction, characterization, and reinsertion was successfully used to measure average density and characterize the concentration within the cloud. Testing focused on mixing vessels using intermitent jet mixers oriented vertically downward. Descriptions of the instruments and instrument performance are presented. These techniques were an effective approach to characterize mixing phenomena, determine mixing energy required to fully mobilize vessel contents, and to determine mixing times for process evaluation.
Physics Division progress report for period ending September 30, 1984
Livingston, A.B. (ed.)
1985-01-01
The research activities of the Division are centered primarily in three areas: experimental nuclear physics, experimental atomic physics, and theoretical nuclear and atomic physics. The largest of these efforts, experimental nuclear physics, is dominated by the heavy ion research program. A major responsibility under this program is the operation of the Holifield Heavy Ion Research Facility as a national user facility. During the period of this report, the facility has begun routine operation for the experimental program. The experimental atomic physics program has two components: the accelerator-based studies of basic collisional phenomena and the studies in support of the controlled fusion program. Also associated with the fusion-related studies are a plasma diagnostics program and the operation of an atomic physics data center. The theoretical physics program, both nuclear and atomic, is covered. This program has benefited this year from the success of the VAX-AP computer system and from the increase in manpower provided by the ORNL/University of Tennessee Distinguished Scientist Program. Smaller programs in applications and high-energy physics are summarized. During the period of this report, we continued to explore possible future extensions of the Holifield Facility. We retain a strong interest in a relativistic heavy-ion collider in the 10 x 10 GeV/nuclear energy range. The ideas for such a facility, described in last year's report, have been modified to utilize the HHIRF 25 MV tandem accelerator as the first stage. Finally, the report concludes with some general information on publications, Division activities, and personnel changes.
IUPAC Periodic Table of Isotopes for the Educational Community
Holden N. E.; Holden,N.E.; Coplen,T.B.
2012-07-15
John Dalton first proposed the concept of atomic weights of the elements in the first decade of the nineteenth century. These atomic weights of the chemical elements were thought of as constants of nature, similar to the speed of light. Dmitri Mendeleev arranged the atomic weights of the elements in ascending order of value and used the systematic variation of their chemical properties to produce his Periodic Table of the Elements in 1869. Measurement of atomic weight values became an important chemical activity for a century and a half. Theodore Richards received a Noble Prize for his work in this area. In 1913, Fredrick Soddy found a species of radium, which had an atomic weight value of 228, compared to the familiar radium gas value of 226. Soddy coined the term 'isotope' (Greek for 'in the same place') to account for this second atomic weight value in the radium position of the Periodic Table. Both of these isotopes of radium are radioactive. Radioactive isotopes are energetically unstable and will decay (disintegrate) over time. The time it takes for one half of a sample of a given radioactive isotope to decay is the half-life of that isotope. In addition to having different atomic weight values, radium-226 and radium-228 also have different half-life values. Around the same time as Soddy's work, J.J. Thomson (discoverer of the electron) identified two stable (non-radioactive) isotopes of the same element, neon. Over the next 40 years, the majority of the known chemical elements were found to have two or more stable (or long-lived radioactive isotopes that contribute significantly to the determination of the atomic weights of the elements).
Nonlinear Dynamics, Magnitude-Period Formula and Forecasts on Earthquake
Yi-Fang Chang
2008-02-02
Based on the geodynamics, an earthquake does not take place until the momentum-energy excess a faulting threshold value of rock due to the movement of the fluid layer under the rock layer and the transport and accumulation of the momentum. From the nonlinear equations of fluid mechanics, a simplified nonlinear solution of momentum corresponding the accumulation of the energy could be derived. Otherwise, a chaos equation could be obtained, in which chaos corresponds to the earthquake, which shows complexity on seismology, and impossibility of exact prediction of earthquakes. But, combining the Carlson-Langer model and the Gutenberg-Richter relation, the magnitude-period formula of the earthquake may be derived approximately, and some results can be calculated quantitatively. For example, we forecast a series of earthquakes of 2004, 2009 and 2014, especially in 2019 in California. Combining the Lorenz model, we discuss the earthquake migration to and fro. Moreover, many external causes for earthquake are merely the initial conditions of this nonlinear system.
Lithospheric Thickness Modeled from Long Period Surface Wave Dispersion
Pasyanos, M E
2008-05-15
The behavior of surface waves at long periods is indicative of subcrustal velocity structure. Using recently published dispersion models, we invert surface wave group velocities for lithospheric structure, including lithospheric thickness, over much of the Eastern Hemisphere, encompassing Eurasia, Africa, and the Indian Ocean. Thicker lithosphere under Precambrian shields and platforms are clearly observed, not only under the large cratons (West Africa, Congo, Baltic, Russia, Siberia, India), but also under smaller blocks like the Tarim Basin and Yangtze craton. In contrast, it is found that remobilized Precambrian structures like the Saharan Shield and Sino-Korean Paraplatform do not have well-established lithospheric keels. The thinnest lithospheric thickness is found under oceanic and continental rifts, as well as along convergence zones. We compare our results to thermal models of continental lithosphere, lithospheric cooling models of oceanic lithosphere, lithosphere-asthenosphere boundary (LAB) estimates from S-wave receiver functions, and velocity variations of global tomography models. In addition to comparing results for the broad region, we examine in detail the regions of Central Africa, Siberia, and Tibet. While there are clear differences in the various estimates, overall the results are generally consistent. Inconsistencies between the estimates may be due to a variety of reasons including lateral and depth resolution differences and the comparison of what may be different lithospheric features.
Periodically-driven quantum matter: the case of resonant modulations
N. Goldman; J. Dalibard; M. Aidelsburger; N. R. Cooper
2015-03-06
Quantum systems can show qualitatively new forms of behavior when they are driven by fast time-periodic modulations. In the limit of large driving frequency, the long-time dynamics of such systems can often be described by a time-independent effective Hamiltonian, which is generally identified through a perturbative treatment. Here, we present a general formalism that describes time-modulated physical systems, in which the driving frequency is large, but resonant with respect to energy spacings inherent to the system at rest. Such a situation is currently exploited in optical-lattice setups, where superlattice (or Wannier-Stark-ladder) potentials are resonantly modulated so as to control the tunneling matrix elements between lattice sites, offering a powerful method to generate artificial fluxes for cold-atom systems. The formalism developed in this work identifies the basic ingredients needed to generate interesting flux patterns and band structures using resonant modulations. Additionally, our approach allows for a simple description of the micro-motion underlying the dynamics; we illustrate its characteristics based on diverse dynamic-lattice configurations. It is shown that the impact of the micro-motion on physical observables strongly depends on the implemented scheme, suggesting that a theoretical description in terms of the effective Hamiltonian alone is generally not sufficient to capture the full time-evolution of the system.
Physics division. Progress report for period ending September 30, 1996
Ball, S.J. [ed.
1997-04-01
This report covers the research and development activities of the Physics Division for the 1995 and 1996 fiscal years, beginning October 1, 1994, and ending September 30, 1996. The activities of the Division continue to be concentrated in the areas of experimental nuclear physics, experimental atomic physics, and theoretical nuclear and atomic physics. In addition, there are smaller programs in plasma diagnostics and data compilation and evaluation. During the period of this report, there has been considerable success in bringing the Holifield Radioactive Ion Beam Facility (HRIBF) into routine operation. The budgets of the nuclear physics portion of the Division have increased each year in nearly all areas, and several new members have been added to the Division research and development staff. On August 30, 1996, the HRIBF successfully accelerated its first radioactive ion beams, {sup 69}As and {sup 70}As. Prior to this, the heart of the facility, the RIB injector system, was completed, including installation of a remote handling system for the target/ion source assembly. Target and ion source development is likely to be the technical key to success of the HRIBF. We have expanded our efforts in those development areas. Of special note is the development of highly permeable composite targets which have now been shown to allow release of difficult-to-produce radioactive ions such as {sup 17,18}F. A summary of the HRIBF work is provided in Chapter 1, along with supporting activities of the Joint Institute for Heavy Ion Research.
Periodic Accretion Instabilities in the Protostar L1634 IRS 7
Hodapp, Klaus W
2015-01-01
The small molecular cloud Lynds 1634 contains at least three outflow sources. We found one of these, IRS 7, to be variable with a period of 37.14 +/- 0.04 days and an amplitude of approximately 2 mag in the Ks band. The light curve consists of a quiescent phase with little or no variation, and a rapid outburst phase. During the outburst phase, the rapid brightness variation generates light echoes that propagate into the surrounding molecular cloud, allowing a measurement of the distance to IRS 7 of 404 pc +/- 35 pc. We observed only a marginally significant change in the H - K color during the outburst phase. The K-band spectrum of IRS 7 shows CO bandhead emission but its equivalent width does not change significantly with the phase of the light curve. The H_2 1-0 S(1) line emission does not follow the variability of the continuum flux. We also used the imaging data for a proper motion study of the outflows originating from the IRS 7 and the FIR source IRAS 05173-0555, and confirm that these are indeed distin...
Large deviations for quasi-periodic cocycles with singularities
Pedro Duarte; Silvius Klein
2015-07-10
We derive large deviations type (LDT) estimates for linear cocycles over an ergodic multifrequency torus translation. These models are called quasi-periodic cocycles. We make the following assumptions on the model: the translation vector satisfies a generic Diophantine condition, and the fiber action is given by a matrix valued analytic function of several variables which is not identically singular. The LDT estimates obtained here depend on some uniform measurements on the cocycle. Our general results derived in [9] regarding the continuity properties of the Lyapunov exponents (LE) and of the Oseledets filtration and decompositions are then applicable, and we obtain local weak-Holder continuity of these quantities in the presence of gaps in the Lyapunov spectrum. The main new feature of this work is allowing a cocycle depending on several variables to have singularities, i.e. points of non invertibility. This requires a careful analysis of the set of zeros of certain analytic functions of several variables and of the singularities (i.e. negative infinity values) of pluri-subharmonic functions related to the iterates of the cocycle. A refinement of this method in the one variable case leads to a stronger LDT estimate and in turn to a stronger, nearly-Holder modulus of continuity of the LE, Oseledets filtration and Oseledets decomposition. This is a draft of a chapter in our forthcoming research monograph [9].
THE DECAYING LONG-PERIOD OSCILLATION OF A STELLAR MEGAFLARE
Anfinogentov, S.; Nakariakov, V. M.; Mathioudakis, M.; Van Doorsselaere, T.; Kowalski, A. F.
2013-08-20
We analyze and interpret the oscillatory signal in the decay phase of the U-band light curve of a stellar megaflare observed on 2009 January 16 on the dM4.5e star YZ CMi. The oscillation is well approximated by an exponentially decaying harmonic function. The period of the oscillation is found to be 32 minutes, the decay time about 46 minutes, and the relative amplitude 15%. As this observational signature is typical of the longitudinal oscillations observed in solar flares at extreme ultraviolet and radio wavelengths, associated with standing slow magnetoacoustic waves, we suggest that this megaflare may be of a similar nature. In this scenario, macroscopic variations of the plasma parameters in the oscillations modulate the ejection of non-thermal electrons. The phase speed of the longitudinal (slow magnetoacoustic) waves in the flaring loop or arcade, the tube speed, of about 230 km s{sup -1} would require a loop length of about 200 Mm. Other mechanisms, such as standing kink oscillations, are also considered.
A renewal theory approach to periodic copolymers with adsorption
Francesco Caravenna; Giambattista Giacomin; Lorenzo Zambotti
2007-10-24
We consider a general model of a heterogeneous polymer chain fluctuating in the proximity of an interface between two selective solvents. The heterogeneous character of the model comes from the fact that the monomer units interact with the solvents and with the interface according to some charges that they carry. The charges repeat themselves along the chain in a periodic fashion. The main question concerning this model is whether the polymer remains tightly close to the interface, a phenomenon called localization, or whether there is a marked preference for one of the two solvents, thus yielding a delocalization phenomenon. In this paper, we present an approach that yields sharp estimates for the partition function of the model in all regimes (localized, delocalized and critical). This, in turn, makes possible a precise pathwise description of the polymer measure, obtaining the full scaling limits of the model. A key point is the closeness of the polymer measure to suitable Markov renewal processes, Markov renewal theory being one of the central mathematical tools of our analysis.
The periodic standing-wave approximation: post-Minkowski computation
Christopher Beetle; Benjamin Bromley; Napoleón Hernández; Richard H. Price
2007-08-08
The periodic standing wave method studies circular orbits of compact objects coupled to helically symmetric standing wave gravitational fields. From this solution an approximation is extracted for the strong field, slowly inspiralling motion of black holes and binary stars. Previous work on this model has dealt with nonlinear scalar models, and with linearized general relativity. Here we present the results of the method for the post-Minkowski (PM) approximation to general relativity, the first step beyond linearized gravity. We compute the PM approximation in two ways: first, via the standard approach of computing linearized gravitational fields and constructing from them quadratic driving sources for second-order fields, and second, by solving the second-order equations as an ``exact'' nonlinear system. The results of these computations have two distinct applications: (i) The computational infrastructure for the ``exact'' PM solution will be directly applicable to full general relativity. (ii) The results will allow us to begin supplying initial data to collaborators running general relativistic evolution codes.
visible and invisible light from across the Cosmos SKA (Square Kilometre Array) SKA will be the world nuclear power ALMA E-ELT GAIAJWST XMM SKA sea level 690km 384,400km ALMA (Atacama Large Millimetre Array) ALMA is a giant array of 66 antennas observing at millimetre/submillimetre wavelengths. Location
A. UDALSKI; M. KUBIAK; M. SZYMANSKI; J. KALUZNY; M. MATEO; W. KRZEMINSKI
1995-01-09
This paper is the first part of the Catalog of Periodic Variable Stars in the Galactic bulge. The Catalog is based on observations collected during the OGLE microlensing search. 213 periodic variable stars brighter than I=18 mag: 31 pulsating, 116 eclipsing and 66 miscellaneous type variables from the Baade's Window BWC field are presented. Periodic variable stars from remaining 20 fields will be presented in similar form in the next parts of the Catalog. The Catalog as well as observations of all periodic variable objects are available to astronomical community over the Internet network.
EIS-0388: Extension of Scoping Period for the Notice of Intent...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Extension of Scoping Period for the Notice of Intent to Prepare an Environmental Impact Statement EIS-0388: Extension of Scoping Period for the Notice of Intent to Prepare an...
EIS-0380: Notice to Extend Comment Period on the Draft Site-Wide...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
to Extend Comment Period on the Draft Site-Wide Environmental Impact Statement EIS-0380: Notice to Extend Comment Period on the Draft Site-Wide Environmental Impact Statement...
The effect of periodic-unsteady wakes, curvature, and pressure gradient on boundary-layer transition
Radke, Robert Edward
1994-01-01
periodic-unsteady wakes. In addition, a turbomachinery cascade test facility with periodic-unsteady inlet flow was designed and manufactured for the next generation of research in this area....
Taxonomy of periodic nets and the design of materials Olaf Delgado-Friedrichs,a
Yaghi, Omar M.
Taxonomy of periodic nets and the design of materials Olaf Delgado-Friedrichs,a Michael O classification (taxonomy) of polyhedra and periodic nets that is appropriate for identifying the structures
Klages, Rainer
Lyapunov instability for a periodic Lorentz gas thermostated by deterministic scattering K assess the nonlinear properties of this dynamical system by numerically calculating its Lyapunov exponents. Based on a revised method for computing Lyapunov exponents, which employs periodic
Victoria, University of
A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical of Mechanical Engineering) ABSTRACT Within a wave energy converter's operational bandwidth, device operation
Outburst-related period changes of recurrent nova CI aquilae
Wilson, R. E.; Honeycutt, R. K., E-mail: honey@astro.indiana.edu, E-mail: rewilson@ufl.edu [Astronomy Department, Indiana University, Swain Hall West, Bloomington, IN 47405 (United States)
2014-11-01
Pre-outburst and post-outburst light curves and post-outburst eclipse timings are analyzed to measure any period (P) change related to nova CI Aql's outburst of early 2000 and a mean post-outburst dP/dt, which then lead to estimates of the accreting component's rate of mass (M) change and its overall outburst-related change of mass over roughly a decade of observations. We apply a recently developed procedure for unified analysis of three timing-related data types (light curves, radial velocities, and eclipse timings), although with only light curves and timings in this case. Fits to the data are reasonably good without need for a disk in the light-curve model, although the disk certainly exists and has an important role in our post-outburst mass flow computations. Initial experiments showed that, although there seems to be an accretion hot spot, it has essentially no effect on derived outburst-related ?P or on post-outburst dP/dt. Use of atomic time (HJED) in place of HJD also has essentially nil effect on ?P and dP/dt. We find ?P consistently negative in various types of solutions, although at best only marginally significant statistically in any one experiment. Pre-outburst HJD {sub 0} and P results are given, as are post-outburst HJD {sub 0}, P, and dP/dt, with light curves and eclipse times as joint input, and also with only eclipse time input. Post-outburst dP/dt is negative at about 2.4?. Explicit formulae for mass transfer rates and epoch-to-epoch mass change are developed and applied. A known offset in the magnitude zero point for 1991-1994 is corrected.
Steady-State Electrical Conduction in the Periodic Lorentz Gas
N. I. Chernov; G. L. Eyink; J. L. Lebowitz; Ya. G. Sinai
1993-02-08
We study nonequilibrium steady states in the Lorentz gas of periodic scatterers when an external field is applied and the particle kinetic energy is held fixed by a ``thermostat'' constructed according to Gauss' principle of least constraint (a model problem previously studied numerically by Moran and Hoover). The resulting dynamics is reversible and deterministic, but does not preserve Liouville measure. For a sufficiently small field, we prove the following results: (1) existence of a unique stationary, ergodic measure obtained by forward evolution of initial absolutely continuous distributions, for which the Pesin entropy formula and Young's expression for the fractal dimension are valid; (2) exact identity of the steady-state thermodyamic entropy production, the asymptotic decay of the Gibbs entropy for the time-evolved distribution, and minus the sum of the Lyapunov exponents; (3) an explicit expression for the full nonlinear current response (Kawasaki formula); and (4) validity of linear response theory and Ohm's transport law, including the Einstein relation between conductivity and diffusion matrices. Results (2) and (4) yield also a direct relation between Lyapunov exponents and zero-field transport (=diffusion) coefficients. Although we restrict ourselves here to dimension $d=2,$ the results carry over to higher dimensions and to some other physical situations: e.g. with additional external magnetic fields. The proofs use a well-developed theory of small perturbations of hyperbolic dynamical systems and the method of Markov sieves, an approximation of Markov partitions. In our context we discuss also the van Kampen objection to linear response theory, which, we point out, overlooks the ``structural stability'' of strongly hyperbolic flows.
Progress in Large Period Multilayer Coatings for High Harmonic and Solar Applications
Aquila, Andrew
2008-01-01
large period multilayer coatings for high harmonic and solarBerkeley, CA 94720 Multilayer coatings for normal incidence
DIRECT ENERGY CONVERSION FISSION REACTOR FOR THE PERIOD JUNE 1, 2001 THROUGH SEPTEMBER 30, 2001
L.C. BROWN
2001-09-30
OAK-B135 DIRECT ENERGY CONVERSION FISSION REACTOR FOR THE PERIOD JUNE 1, 2001 THROUGH SEPTEMBER 30, 2001
Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2013-06-15
Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage.
E ective boundary conditions for laminar ows over periodic rough boundaries
Achdou, Yves
E#27;ective boundary conditions for laminar #29;ows over periodic rough boundaries Yves Achdou #3 are proposed for a laminar #29;ow over a rough wall with periodic roughness elements. These e#27;ective is such an approach ? In this paper, we wish to answer these questions for laminar #29;ows over periodic rough walls
THE EFFECT OF A REFRACTORY PERIOD ON THE POWER SPECTRUM OF NEURONAL DISCHARGE
Bair, Wyeth
produce peaks in the power spectrum near 40 Hz. Key words. neuronal spike trains, refractory periodTHE EFFECT OF A REFRACTORY PERIOD ON THE POWER SPECTRUM OF NEURONAL DISCHARGE JOEL FRANKLIN neuron refractory period and a statistically independent interval due to a stationary external process
Holocene climate instability during the termination of the African Humid Period
Renssen, Hans
Holocene climate instability during the termination of the African Humid Period H. Renssen January 2003; published 25 February 2003. [1] The termination of the Holocene African Humid Period ($9. Goosse, Holocene climate instability during the termination of the African Humid Period, Geophys. Res
Detection and discrimination of the periodicity of prime numbers by discrete Fourier transform
Levente Csoka
2015-01-27
A novel representation of a quasi-periodic modified von Mangoldt function L(n) on prime numbers and its decomposition into Fourier series has been investigated. We focus on some particular quantities characterizing the modified von Mangoldt function. The results indicate that prime number progression can be decomposed into periodic sequences. The main approach is to decompose it into sin or cosine function. Basically, it is applied to extract hidden periodicities in seemingly quasi periodic prime function. Numerical evidences were provided to confirm the periodic distribution of primes.
Andrey Melnikov
2012-12-08
We prove the existence of solutions to the Sturm-Liouville (SL) equation -y"(x)+q(x)y(x) = s^2 y(x) with periodic and quasi-periodic potential q(x) using theory of SL vessels, implementing a Backlund transformation of SL equation. In this paper quasi-periodic means a finite sum of periodic integrable functions. The solutions for a general s are explicitly constructed in terms of the solutions zn(x), satisfying the SL equation with initial conditions zn(0)=0, zn'(0)=1 for a discrete Levinson set of numbers s=sn, n-natural number. The tau function tau(x) of the corresponding vessel realizes the given potential via the formula q(x)= - 2(ln(tau(x)))". We also prove an analogue of the inverse scattering theorem in this setting too. Using the notion of "KdV evolutionary vessel", we construct a solution of the Korteweg-de-Vries (KdV) equation q'_t = - 3/2 q q'_x + 1/4 q"'_{xxx}, which coincides for t=0 with a given (periodic or quasi-periodic) potential.
Property:OpenEI/UtilityRate/DemandChargePeriod7FAdj | Open Energy...
Jump to: navigation, search This is a property of type Number. Name: Demand Charge Period 7 Fuel Adj Retrieved from "http:en.openei.orgwindex.php?titleProper...
[2008, 23pp]---On certain period relations for cusp forms on GL_n.pdf
2008-07-24
International Mathematics Research Notices, Vol. 2008, Article ID rnn077, .... sponds to a Hilbert modular form of CM type, then our period relations are formally ...
EIS-0466: Re-opening of Public Scoping Period and Announcement...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Public Scoping Meetings Continued Operation of the Sandia National Laboratories, New Mexico Comment Period Ends: 9122011 Submit Comments to: Ms. Jeanette Norte NNSA Sandia Site...
EIS-0350-S1: Extension of the Public Review and Comment Period...
Broader source: Energy.gov (indexed) [DOE]
Period and Announcement of an Additional Public Hearing for the Draft Supplemental Environmental Impact Statement for the Nuclear Facility Portion of the Chemistry and Metallurgy...
Computer Assisted 'Proof' of the Global Existence of Periodic Orbits in the Rössler System
A. E. Botha; W. Dednam
2014-08-14
The numerical optimized shooting method for finding periodic orbits in nonlinear dynamical systems was employed to determine the existence of periodic orbits in the well-known R\\"ossler system. By optimizing the period $T$ and the three system parameters, $a$, $b$ and $c$, simultaneously, it was found that, for any initial condition $(x_0,y_0,z_0) \\in \\Re^3$, there exists at least one set of optimized parameters corresponding to a periodic orbit passing through $ (x_0,y_0,z_0)$. After a discussion of this result it was concluded that its analytical proof may present an interesting new mathematical challenge.
Measuring the rotation period distribution of field M-dwarfs with Kepler
McQuillan, Amy; Mazeh, Tsevi
2013-01-01
We have analysed 10 months of public data from the Kepler space mission to measure rotation periods of main-sequence stars with masses between 0.3 and 0.55 M_sun. To derive the rotational period we introduce the autocorrelation function and show that it is robust against phase and amplitude modulation and residual instrumental systematics. Of the 2483 stars examined, we detected rotation periods in 1570 (63.2%), representing an increase of a factor ~ 30 in the number of rotation period determination for field M-dwarfs. The periods range from 0.37-69.7 days, with amplitudes ranging from 1.0-140.8 mmags. The rotation period distribution is clearly bimodal, with peaks at ~ 19 and ~ 33 days, hinting at two distinct waves of star formation, a hypothesis that is supported by the fact that slower rotators tend to have larger proper motions. The two peaks of the rotation period distribution form two distinct sequences in period-temperature space, with the period decreasing with increasing temperature, reminiscent of ...
DOE Extends Comment Period on Notice of Inquiry Under the Energy...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Act of 2007, which implements the Convention on Supplementary Compensation for Nuclear Damage. The public comment period will be extended to October 27, 2010. The signed extension...
A Low-Cost, High-Efficiency Periodic Flow Gas Turbine for Distributed Energy Generation
Dr. Adam London
2008-06-20
The proposed effort served as a feasibility study for an innovative, low-cost periodic flow gas turbine capable of realizing efficiencies in the 39-48% range.
EIS-0250-S2 and EIS-0369: Notice of Public Comment Period Extension...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Notice of Public Comment Period Extension and Additional Public Meeting Supplemental Yucca Mountain Rail Corridor and Rail Alignment The Department of Energy announced an...
EIS-0299: Notice of Extension of Comment Period for the Environmental...
Broader source: Energy.gov (indexed) [DOE]
period on the environmental impact statement (EIS) for the Proposed Production of Plutonium-238 for Use in Advanced Radioisotope Power Systems for Future Space Missions from...
2Dimensional localization of acoustic waves in random perturbation of periodic media.
2ÂDimensional localization of acoustic waves in random perturbation of periodic media. Hatem NAJAR to the spectral properties of the relevant selfÂadjoint di#erential operator. As far as the acoustic waves, electromagnetic or acoustic) waves in a periodic meÂ dia perturbed by random impurities. See [7, 8, 9, 10
Guide to Library Resources for English 110 Finding Books, Periodicals, Microforms and Media
Cakoni, Fioralba
the Library of Congress Classification System. Each book (or bound volume of a periodical) is assigned a call1 Guide to Library Resources for English 110 Finding Books, Periodicals, Microforms and Media held by the University of Delaware Library, you may wish to start by searching DELCAT or WorldCat Local
Periodic Cooling of Bird Eggs Reduces Embryonic Growth Efficiency Christopher R. Olson*
Vleck, Carol
927 Periodic Cooling of Bird Eggs Reduces Embryonic Growth Efficiency Christopher R. Olson* Carol M, periodic cooling occurs when the in- cubating adult leaves the nest to forage, but the effects of pe- riodic cooling on embryo growth, yolk use, and metabolism are poorly known. To address this question, we
CONTROLLING ENERGY INTAKE IN THE PREPARTUM PERIOD TO IMPROVE TRANSITION COW HEALTH
Farrell, Anthony P.
CONTROLLING ENERGY INTAKE IN THE PREPARTUM PERIOD TO IMPROVE TRANSITION COW HEALTH by LORI ANN A common feeding practice during the dry period is to switch dairy cows to a low forage, energy dense diet 3 weeks prepartum, but this practice has been criticized as it may lead to the overconsumption
Interrogation of a long-period grating using a mechanically scannable arrayed waveguide grating
Yao, Jianping
); published July 16, 2008 A novel technique to interrogate a long-period grating (LPG) using a mechanically of the LPG is measured. An interrogation system with a resolution of 10 pm at a speed of 10 Hz-period-grating (LPG) sensors have found exten- sive applications ranging from temperature monitor- ing, mechanical
Characterization of LMS and DMR Beamformers in the Presence of Loud Periodic Interferers
George Mason University
Characterization of LMS and DMR Beamformers in the Presence of Loud Periodic Interferers Geoffrey C introduced loud impulsive periodic interferers into these systems. Standard LMS adaptive beamforming interference. 1. INTRODUCTION Adaptive Least Mean-Square (LMS) beamformers are efficient algorithms, providing
Efficient Solvers for Nonlinear Time-Periodic Eddy Current F. Bachinger
Schoeberl, Joachim
Efficient Solvers for Nonlinear Time-Periodic Eddy Current Problems F. Bachinger U. Langer J. Sch-periodic eddy current problems, ranging from the description of the nonlinearity to an efficient solution setup, the magnetic field and the thereby generated eddy currents hardly penetrate into conducting
Traveling Waves Solutions for Bistable Differential-Difference Equations with Periodic Diffusion
Elmer, Christopher E.; Van Vleck, Erik
2001-10-05
on the underlying lattice as well as on time. For the case of spatially periodic diffusion we obtain analytic solutions for the traveling wave problem using a piecewise linear nonlinearity. The formula for the wave forms is implicitly defined in the general periodic...
Trepanation in South-Central Peru During the Early Late Intermediate Period (ca. AD 10001250)
Cosmides, Leda
Trepanation in South-Central Peru During the Early Late Intermediate Period (ca. AD 1000-two individuals from Andahuaylas, AMS radiocarbon dated to the early Late Intermediate Period (ca. AD 1000 grooving, drilling and boring, and lin- ear cutting were far less successful. Evidence of perioperative
Comparison of quantization of charge transport in periodic and open pumps
Comparison of quantization of charge transport in periodic and open pumps G.M. Graf and G. Ortelli the charges transported in two systems, a spatially periodic and an open quantum pump, both depending physical situations become the same, i.e., that of a large open pump. 1 Introduction In this note we
Temporal evolution of long-timescale periodicities in ULX NGC 5408 X-1
An, Tao; Wang, Jun-Yi
2015-01-01
Context. NGC 5408 X-1 is one of the few ultraluminous X-ray sources with an extensive monitoring program in X-rays (a temporal baseline of 4.2 yr), making it one of the most suitable candidates to study the long-timescale quasi-periodic oscillations (QPOs). Aims. Previous timing analysis of the Swift data of NGC 5408 X-1 led to detection of multiple periodicities ranging from 2.6 d to 230 d. In this paper, we focus on the statistical significance and the temporal evolution of these periodicities. Methods. A time-series analysis technique in the time-frequency domain, the weighted wavelet Z-transform (WWZ), was employed to identify the periodicities and trace their variations with time. Results. Three periodic components were detected from the WWZ periodogram, corresponding to periods of 2.65$\\pm$0.01 d, 115.4$\\pm$14.4 d and 189.1$\\pm$15.2 d. All three have statistical significance higher than 99.74%. The 2.65-d periodicity is quite stable in the majority of the light curve. The 115-d periodicity is the most p...
Transport and Fractionation in Periodic Potential-Energy Landscapes Matthew Pelton and Kosta Ladavac
Grier, David
. Grier Dept. of Physics and Center for Soft Matter Research New York University, New York, NY 10003Transport and Fractionation in Periodic Potential-Energy Landscapes Matthew Pelton and Kosta (Dated: January 2, 2012) Objects driven through periodically modulated potential-energy landscapes in two
QUANTUM ENERGY EXPECTATION IN PERIODIC TIME-DEPENDENT HAMILTONIANS VIA GREEN
1. Introduction Consider a general periodically driven quantum hamiltonian system H(t) = H0 + V (t the system then Um F is this state at time m. Typically, the unper- turbed hamiltonian H0 is assumed to have accelerator in which a particle can acquire unbounded energy from collisions with a heavy periodically moving
Numerical implementation of static Field Dislocation Mechanics theory for periodic media
Acharya, Amit
Numerical implementation of static Field Dislocation Mechanics theory for periodic media R of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St., Urbana, IL investigates the implementation of Field Dislocation Mechanics theory for media with a periodic microstructure
Stable all-optical limiting in nonlinear periodic structures. I. Analysis
Pelinovsky, Dmitry
Stable all-optical limiting in nonlinear periodic structures. I. Analysis Dmitry Pelinovsky consider propagation of coherent light through a nonlinear periodic optical structure consisting of two al-dependent dy- namics. We find the domain for existence of true all-optical limiting when the input
Periodic migration in a physical model of cells on micropatterns Brian A. Camley,1, 2
Li, Bo
Periodic migration in a physical model of cells on micropatterns Brian A. Camley,1, 2 Yanxiang Zhao, bipedal motion, and periodic migration, in which the cell crawls persistently in one direction before-dimensional extracellular ma- trix (ECM). However, cells in ECM often exhibit qualitatively different modes of migration
Predicting short-period, wind-wave-generated seismic1 noise in coastal regions2
Tsai, Victor C.
Predicting short-period, wind-wave-generated seismic1 noise in coastal regions2 Florent Gimberta recorded in this period range is mostly caused by local wind-waves, i.e. by wind-waves occurring within in nearly opposite directions is orders of magnitude smaller than previously suggested for wind-waves, does
Semi-automatic Construction of Cross-period Thesaurus Chaya Liebeskind, Ido Dagan, Jonathan Schler
Wintner, Shuly
Semi-automatic Construction of Cross-period Thesaurus Chaya Liebeskind, Ido Dagan, Jonathan Schler-period (Diachronic) Thesaurus Automatic generation of candidates Research objective Our task: · Support searches of cultural resources · High-quality diachronic thesaurus construction Semi-automatic setting Hardly explored
Emergence of unsteady dark solitary waves from coalescing spatially-periodic patterns
Bridges, Tom
Emergence of unsteady dark solitary waves from coalescing spatially-periodic patterns Thomas J of the defocussing nonlinear Schrödinger equation. In this paper the interest is in a mechanism for the emergence is on the periodic state at innity as the generator. It is shown that a natural mechanism for the emergence
Potsdam Thinkshop Poster Proceedings, p. 4345 Rotational periods of very young brown dwarfs in Cha I
Joergens, Viki
telescope at ESO. We performed aperture photometry and calculated differential magnitudes by means for unevenly spaced data as in our case. The algorithm phase folds the data with a trial period and calculates modulates the total brightness of the star and leads to periodic light vari- Correspondence to: viki@mpe.mpg
Local energy decay and Strichartz estimates for the wave equation with time-periodic
Petkov, Vesselin
Local energy decay and Strichartz estimates for the wave equation with time-periodic perturbations(z) = (U(T, 0) - z)-1 , (x) C 0 (Rn ), where U(t, s) is the propagator related to the wave equation) and T > 0 is the period. Assuming that R(z) has no poles z with |z| 1, we establish a local energy decay
Multi-Period Production Capacity Planning for Integrated Product and Production System Design*
Saitou, Kazuhiro "Kazu"
Multi-Period Production Capacity Planning for Integrated Product and Production System Design* Emre.ac.uk kazu@umich.edu .Abstract This paper presents a simulation-based method to aid multi-period production capacity planning by quantifying the trade-off between product quality and production cost. The product
Margaliot, Michael
1 Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several artificial biological systems that entrain to a common
Sontag, Eduardo
Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene to the solar day. In the terminology of systems theory, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several
Fejer, Martin M.
June 15, 1996 / Vol. 21, No. 12 / OPTICS LETTERS 857 Photorefractive effects in periodically poled-state photorefractive index perturbations caused by a given optical irradiance distribution in a periodically poled are reduced compared with those in a homogeneously poled crystal by approximately the square of the product
Mondrik, Nicholas; Marshall, Jennifer L
2015-01-01
We present a new method of extending the single band Analysis of Variance period estimation algorithm to multiple bands. We use SDSS Stripe 82 RR Lyrae to show that in the case of low number of observations per band and non-simultaneous observations, improvements in period recovery rates of up to $\\approx$60\\% are observed. We also investigate the effect of inter-band observing cadence on period recovery rates. We find that using non-simultaneous observation times between bands is ideal for the multiband method, and using simultaneous multiband data is only marginally better than using single band data. These results will be particularly useful in planning observing cadences for wide-field astronomical imaging surveys such as LSST. They also have the potential to improve the extraction of transient data from surveys with few ($\\lesssim 30$) observations per band across several bands, such as the Dark Energy Survey.
A survey for very short-period planets in the Kepler data
Jackson, Brian; Stark, Christopher C.; Chambers, John; Adams, Elisabeth R.; Deming, Drake
2013-12-20
We conducted a search for very short-period transiting objects in the publicly available Kepler data set. Our preliminary survey has revealed four planetary candidates, all with orbital periods less than 12 hr. We have analyzed the data for these candidates using photometric models that include transit light curves, ellipsoidal variations, and secondary eclipses to constrain the candidates' radii, masses, and effective temperatures. Even with masses of only a few Earth masses, the candidates' short periods mean that they may induce stellar radial velocity signals (a few m s{sup –1}) detectable by currently operating facilities. The origins of such short-period planets are unclear, but we discuss the possibility that they may be the remnants of disrupted hot Jupiters. Whatever their origins, if confirmed as planets, these candidates would be among the shortest-period planets ever discovered. Such planets would be particularly amenable to discovery by the planned TESS mission.
Name:______________ Period:_____________
Lega, Joceline
cup to balance the system again. Fill in the following table for when the system is balanced: Plot on the line and finding the ratio (expressed as a fraction) of the change in the y- coordinates to the change in the x- coordinates. slope= rise run = y2-y1 x2-x1 6: Label two points in the line and fill
Klotz, David
2015-01-01
the Great, Persia invaded Egypt twice and administered it asEl- Qeis) in Upper Egypt (BM 37496; Yoyotte 1972b: pl. 19a;sites are on the fringes of Egypt: Kharga Oasis to the west,
Williamson, Jacquelyn
2015-01-01
The city of Akhenaten I. London: Egypt Exploration Society.of Akhenaten III. London: Egypt Exploration Society. Petrie,the American Research Center in Egypt 25, pp. 117-121. 1991
Formation of laser-induced periodic surface structures on niobium by femtosecond laser irradiation
Pan, A.; Dias, A.; Gomez-Aranzadi, M.; Olaizola, S. M. [CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain); CEIT-IK4 and Tecnun, University of Navarra, Manuel Lardizábal 15, 20018 San Sebastián (Spain); Rodriguez, A. [CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain)
2014-05-07
The surface morphology of a Niobium sample, irradiated in air by a femtosecond laser with a wavelength of 800?nm and pulse duration of 100 fs, was examined. The period of the micro/nanostructures, parallel and perpendicularly oriented to the linearly polarized fs-laser beam, was studied by means of 2D Fast Fourier Transform analysis. The observed Laser-Induced Periodic Surface Structures (LIPSS) were classified as Low Spatial Frequency LIPSS (periods about 600?nm) and High Spatial Frequency LIPSS, showing a periodicity around 300?nm, both of them perpendicularly oriented to the polarization of the incident laser wave. Moreover, parallel high spatial frequency LIPSS were observed with periods around 100?nm located at the peripheral areas of the laser fingerprint and overwritten on the perpendicular periodic gratings. The results indicate that this method of micro/nanostructuring allows controlling the Niobium grating period by the number of pulses applied, so the scan speed and not the fluence is the key parameter of control. A discussion on the mechanism of the surface topology evolution was also introduced.
The Lyapunov function for Schrödinger operators with a periodic 2x2 matrix potential
Andrei Badanin; Jochen Brüning; Evgeny Korotyaev
2005-08-29
We consider the Schr\\"odinger operator on the real line with a 2x2 matrix valued 1-periodic potential. The spectrum of this operator is absolutely continuous and consists of intervals separated by gaps. We define a Lyapunov function which is analytic on a two sheeted Riemann surface. On each sheet, the Lyapunov function has the same properties as in the scalar case, but it has branch points, which we call resonances. We prove the existence of real as well as non-real resonances for specific potentials. We determine the asymptotics of the periodic and anti-periodic spectrum and of the resonances at high energy. We show that there exist two type of gaps: 1) stable gaps, where the endpoints are periodic and anti-periodic eigenvalues, 2) unstable (resonance) gaps, where the endpoints are resonances (i.e., real branch points of the Lyapunov function). We also show that periodic and anti-periodic spectrum together determine the spectrum of the matrix Hill operator.
Waszczak, Adam; Ofek, Eran O; Laher, Russ; Masci, Frank; Levitan, David; Surace, Jason; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke; Helou, George; Prince, Thomas A; Kulkarni, Shrinivas
2015-01-01
We fit 54,296 sparsely-sampled asteroid lightcurves in the Palomar Transient Factory to a combined rotation plus phase-function model. Each lightcurve consists of 20+ observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude and other attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining 53,000 fitted periods. By this method we find 9,033 of our lightcurves (of 8,300 unique asteroids) have reliable periods. Subsequent consideration of asteroids with multiple lightcurve fits indicate 4% contamination in these reliable periods. For 3,902 lightcurves with sufficient phase-angle coverage and either a reliably-fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimo...
Effective slip boundary conditions for arbitrary periodic surfaces: the surface mobility tensor
Kamrin, Kenneth N.
In a variety of applications, most notably microfluidics design, slip-based boundary conditions have been sought to characterize fluid flow over patterned surfaces. We focus on laminar shear flows over surfaces with periodic ...
Kaber, David B.
2009-01-01
Human Factors and Ergonomics in Manufacturing, Vol. 19 (6) 601621 (2009) C 2009 Wiley Periodicals. Correspondence to: David Kaber, The Ergonomics Laboratory, Edward P. Fitts Department of Industrial & Systems
CO2 Abatement in the UK Power Sector: Evidence from the EU ETS Trial Period
Ellerman, A. Denny
2008-01-01
This paper provides an empirical assessment of CO2 emissions abatement in the UK power sector during the trial period of the EU ETS. Using an econometrically estimated model of fuel switching, it separates the impacts of ...
Brolo, Alexandre G.
;evaluation as chemical sensors and a brief comparison of the pPeriodic Metallic Nanostructures as Plasmonic Chemical Sensors Chiara Valsecchi and Alexandre G generation of low- cost and efficient chemical sensors and biosensors. The extensive variety
Discrete Self-Similarity Of RR Lyrae Stars II. Period Spectrum For A Very Large Sample
R. L. Oldershaw
2006-06-06
A recent paper demonstrated a considerable degree of self-similarity between RR Lyrae stars and their atomic scale analogues: excited helium atoms undergoing single-level transition between n = 7 and n = 10. Discrete self-similarity between these fractal analogues was indentified in terms of their masses, radii, oscillation periods, basic morphologies and kinematics. In this second paper on the subject, an extremely large and carefully analyzed sample of RR Lyrae oscillation periods provides further evidence for a unique match between the predicted set of discrete periods, based exclusively on the known helium spectrum and the discrete scaling equations of a fractal cosmological paradigm, and the observed period spectra of RR Lyrae stars.
Glass, Leon
AND CHAOS IN A PERIODICALLY FORCED OSCILLATOR Rafael PEREZ Instituto de Fisica, Universidad Nacional de Mexico, Mexico City, Mexico and Leon GLASS Department of Physiology, McGill University, 3655 Drummond
Monteiro, Emily Anne Janda
2013-05-03
Women’s periodicals at the start of the twentieth-century were not just recorders but also producers of social and cultural change. They can be considered to both represent and construct gender codes, offering readers ...
Fabrication and applications of sub-micron 2D and 3D periodic...
Office of Scientific and Technical Information (OSTI)
Fabrication and applications of sub-micron 2D and 3D periodic carbon structures. Citation Details In-Document Search Title: Fabrication and applications of sub-micron 2D and 3D...
Timeline for HWMs and Above-RHWM Elections (2nd Purchase Period...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
31 st of a Rate Case year, for the upcoming Rate Period: 1. Provide updates to forced outage rating, and planned outages. 2. Chooses operating minimum amounts, if applicable....
EIS-0426: Notice of Extension of Public Comment Period for the...
Broader source: Energy.gov (indexed) [DOE]
Office is extending the public comment period for the Draft Site-wide Environmental Impact Statement for the Nevada National Security Site (NNSS) and Off-Site Locations in...
McLaren, Brian L. (Brian Lloyd), 1958-
2001-01-01
This dissertation examines the intersection of the modern and the colonial in architecture and culture during the period of Italian colonization of North Africa from 1911 to 1943. Rather than see the colonies as merely a ...
Use and Finance BiAnnual Reporting Form Reporting Period: July 2013 through December 2013
Papalambros, Panos
Use and Finance BiAnnual Reporting Form Reporting Period: July 2013 through December 2013 $ Other (Professional Fees, Telecommunications, Moving) 538,200$ Other (Finance resources services center will be established for finance and human resources transaction processing activities
Allen, Matthew S.
Identifying parameters of nonlinear structural dynamic systems using linear time- periodic nonlinearity. 1. Introduction Most dynamical systems behave nonlinearly in the most general scenario. This can point bifurcation [1], in rotor dynamic systems with bearing contact nonlinearities [2], in biomechanics
Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in 't Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)
2014-03-14
A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.
Theoretical and Computational Investigation of Periodically Focused Intense Charged-Particle Beams
Chen, Chiping [Massachusetts Institute of Technology
2013-06-26
The purpose of this report is to summarize results of theoretical and computational investigations of periodically focused intense charged-particle beams in parameter regimes relevant to the development of advanced high-brightness, high-power accelerators for high-energy physics research. The breakthroughs and highlights in our research in the period from April 1, 2010 to March 30, 2013 were: a) Theory and simulation of adiabatic thermal Child-Langmuir flow; b) Particle-in-cell simulations of adiabatic thermal beams in periodic solenoidal focusing field; c)Dynamics of charged particles in an adiabatic thermal beam equilibrium in a periodic solenoidal focusing field; d) Training of undergraduate researchers and graduate student in accelerator and beam physics. A brief introduction and summary is presented. Detailed descriptions of research results are provided in an appendix of publications at the end of the report.
Approximations to wave propagation through doubly-periodic arrays of scatterers
periodic media in many physical contexts that include acoustics, elasticity, electromagnetic theory fluid. The fundamental assumptions behind these approximations are that kL 1 and a/L 1 (and hence ka 1
Microsoft Word - BWCS Scorecard Third period FY 2014 Mar 9 2015...
Office of Environmental Management (EM)
by the material processed fee rate for the period, which happens to be 67Metric Ton. BWCS processed 22,596 MT of DUF 6 . The fee associated with this is 1,513,932. The Total...
Quasi-periodic wiggles of microwave zebra structures in a solar flare
Yu, Sijie; Selzer, L A; Tan, Baolin; Yan, Yihua
2013-01-01
Quasi-periodic wiggles of microwave zebra pattern structures with period range from about 0.5 s to 1.5 s are found in a X-class solar flare on 2006 December 13 at the 2.6-3.8 GHz with the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou). Periodogram and correlation analysis show that the wiggles have two-three significant periodicities and almost in phase between stripes at different frequency. The Alfven speed estimated from the zebra pattern structures is about 700 Km/s. We obtain the spatial size of the waveguiding plasma structure to be about 1 Mm with the detected period of about 1 s. It suggests the ZP wiggles can be associated with the fast mag- netoacoustic oscillations in the flaring active region. The lack of a significant phase shift between wiggles of different stripes suggests that the ZP wiggles are caused by a standing sausage oscillation.
1D, 2D, and 3D Periodic Structures: Electromagnetic Characterization, Design, and Measurement
Brockett, Timothy John
2013-01-01
such as solar cell efficiency and microwave absorber [4].very similar to solar cell arrays is microwave absorber usedsolar cell efficiency. mizing periodic electromagnetic structures at RF and microwave
Paleocene sea level movements with a 430,000 year quasi-periodic...
Office of Scientific and Technical Information (OSTI)
Sea level movements with quasi-periodicity of 430,000 years are identified in the marine sedimentary units of the Eastern Gulf Coastal Plain of Mississippi, Alabama and...
Comparison of quantization of charge transport in periodic and open pumps
Gian Michele Graf; Gregorio Ortelli
2007-09-19
We compare the charges transported in two systems, a spatially periodic and an open quantum pump, both depending periodically and adiabatically on time. The charge transported in a cycle was computed by Thouless, respectively by Buttiker et al. in the two cases. We show that the results agree in the limit where the two physical situations become the same, i.e., that of a large open pump.
Demonstration of sawtooth period control with EC waves in KSTAR plasma
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jeong, J. H.; Bae, Y. S.; Joung, M.; Kim, D.; Goodman, T. P.; Sauter, O.; Sakamoto, K.; Kajiwara, K.; Oda, Y.; Kwak, J. G.; et al
2015-03-12
The sawtooth period control in tokamak is important issue in recent years because the sawtooth crash can trigger TM/NTM instabilities and drive plasmas unstable. The control of sawtooth period by the modification of local current profile near the q=1 surface using ECCD has been demonstrated in a number of tokamaks [1, 2] including KSTAR. As a result, developing techniques to control the sawtooth period as a way of controlling the onset of NTM has been an important area of research in recent years [3]. In 2012 KSTAR plasma campaign, the sawtooth period control is carried out by the different depositionmore »position of EC waves across the q=1 surface. The sawtooth period is shortened by on-axis co-ECCD (destabilization), and the stabilization of the sawtooth is also observed by off-axis co-ECCD at outside q=1 surface. In 2013 KSTAR plasma campaign, the sawtooth locking experiment with periodic forcing of 170 GHz EC wave is carried out to control the sawtooth period. The optimal target position which lengthens the sawtooth period is investigated by performing a scan of EC beam deposition position nearby q=1 surface at the toroidal magnetic field of 2.9 T and plasma current of 0.7 MA. The sawtooth locking by the modulated EC beam is successfully demonstrated as in [3-5] with the scan of modulation-frequency and duty-ratio at the low beta (?N~0.5) plasma. In this paper, the sawteeth behavior by the location of EC beam and the preliminary result of the sawtooth locking experiments in KSTAR will be presented.« less
The discrete spectrum of Jacobi matrix related to recurrence relations with periodic coefficients
V. V. Borzov; E. V. Damaskinsky
2015-02-27
In this note we investigate the discrete spectrum of Jacobi matrix corresponding to polynomials defined by recurrence relations with periodic coefficients. As examples we consider a)the case when period $N$ of coefficients of recurrence relations equals three (as a particular case we consider "parametric" Chebyshev polynomials introduced by authors early); b)the elementary $N$-symmetrical Chebyshev polynomials ($N=3,4,5$), that was introduced by authors in the study of the "composite model of generalized oscillator".
On the spin period distribution in Be/X-ray binaries
Cheng, Z.-Q.; Shao, Y.; Li, X.-D., E-mail: lixd@nju.edu.cn [Department of Astronomy, Nanjing University, Nanjing 210093 (China)
2014-05-10
There is a remarkable correlation between the spin periods of the accreting neutron stars (NSs) in Be/X-ray binaries (BeXBs) and their orbital periods. Recently, Knigge et al. showed that the distribution of the spin periods contains two distinct subpopulations peaked at ?10 s and ?200 s, respectively, and suggested that they may be related to two types of supernovae for the formation of the NSs, i.e., core-collapse and electron-capture supernovae. Here we propose that the bimodal spin period distribution is likely to be ascribed to different accretion modes of the NSs in BeXBs. When the NS tends to capture material from the warped, outer part of the Be star disk and experiences giant outbursts, a radiatively cooling dominated disk is formed around the NS, which spins up the NS and is responsible for the short-period subpopulation. In BeXBs that are dominated by normal outbursts or are persistent, the accretion flow is advection-dominated or quasi-spherical. The spin-up process is accordingly inefficient, leading to longer periods of the neuron stars. The potential relation between the subpopulations and the supernova mechanism is also discussed.
MAGNETIC ROSSBY WAVES IN THE SOLAR TACHOCLINE AND RIEGER-TYPE PERIODICITIES
Zaqarashvili, Teimuraz V.; Carbonell, Marc; Oliver, Ramon; Ballester, Jose Luis E-mail: marc.carbonell@uib.e E-mail: joseluis.ballester@uib.e
2010-02-01
Apart from the eleven-year solar cycle, another periodicity around 155-160 days was discovered during solar cycle 21 in high-energy solar flares, and its presence in sunspot areas and strong magnetic flux has been also reported. This periodicity has an elusive and enigmatic character, since it usually appears only near the maxima of solar cycles, and seems to be related with a periodic emergence of strong magnetic flux at the solar surface. Therefore, it is probably connected with the tachocline, a thin layer located near the base of the solar convection zone, where a strong dynamo magnetic field is stored. We study the dynamics of Rossby waves in the tachocline in the presence of a toroidal magnetic field and latitudinal differential rotation. Our analysis shows that the magnetic Rossby waves are generally unstable and that the growth rates are sensitive to the magnetic field strength and to the latitudinal differential rotation parameters. Variation of the differential rotation and the magnetic field strength throughout the solar cycle enhance the growth rate of a particular harmonic in the upper part of the tachocline around the maximum of the solar cycle. This harmonic is symmetric with respect to the equator and has a period of 155-160 days. A rapid increase of the wave amplitude could give rise to a magnetic flux emergence leading to observed periodicities in solar activity indicators related to magnetic flux.
Dwarf Nova-like Outburst of Short Period Intermediate Polar HT Camelopardalis
Ryoko Ishioka; Taichi Kato; Makoto Uemura; Gary W. Billings; Koichi Morikawa; Ken'ichi Torii; Kenji Tanabe; Arto Oksanen; Harri Hyvonen; Hitoshi Itoh
2002-06-12
We report the first time-series observations of the short outburst of the proposed intermediate polar HT Cam (=RX J0757.0+6306). On 2001 December 29, we detected the object was undergoing a bright outburst at the magnitude of $m_{vis}=12.2$. Following this detection, we started international joint observations through VSNET. The light curve showed a gradual decline for the first 0.5 d. Following this short plateau phase, the rate of decline dramatically increased to more than 4 mag d$^{-1}$. Within 1.5 d from the outburst detection, the object almost declined to the quiescent level. During the rapidly declining phase, long-term modulations with a period of 86 min and strong pulses with a period of 8.6 min were observed. We concluded that 86 min and 8.6 min are the orbital period and the spin period of HT Cam, respectively. By the detection of the spin period, we confirmed the IP classification of HT Cam. However, its outburst behavior rather resembles that of dwarf novae. The discrepancy between the declining rates of the total flux and the pulse flux strongly suggests that the disk instabilities were taking place during the outburst.
Analysis of electromagnetic scattering by nearly periodic structures: an LDRD report.
Johnson, William Arthur; Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Wilton, Donald R. (University of Houston, Houston, TX); Basilio, Lorena I.; Peters, David William; Capolino, F. (University of Houston, Houston, TX)
2006-10-01
In this LDRD we examine techniques to analyze the electromagnetic scattering from structures that are nearly periodic. Nearly periodic could mean that one of the structure's unit cells is different from all the others--a defect. It could also mean that the structure is truncated, or butted up against another periodic structure to form a seam. Straightforward electromagnetic analysis of these nearly periodic structures requires us to grid the entire structure, which would overwhelm today's computers and the computers in the foreseeable future. In this report we will examine various approximations that allow us to continue to exploit some aspects of the structure's periodicity and thereby reduce the number of unknowns required for analysis. We will use the Green's Function Interpolation with a Fast Fourier Transform (GIFFT) to examine isolated defects both in the form of a source dipole over a meta-material slab and as a rotated dipole in a finite array of dipoles. We will look at the numerically exact solution of a one-dimensional seam. In order to solve a two-dimensional seam, we formulate an efficient way to calculate the Green's function of a 1d array of point sources. We next formulate ways of calculating the far-field due to a seam and due to array truncation based on both array theory and high-frequency asymptotic methods. We compare the high-frequency and GIFFT results. Finally, we use GIFFT to solve a simple, two-dimensional seam problem.
Discovery of four periodic methanol masers and updated light curve for a further one
Szymczak, M; Bartkiewicz, A
2015-01-01
We report the discovery of 6.7 GHz methanol maser periodic flares in four massive star forming regions and the updated light curve for the known periodic source G22.357+0.066. The observations were carried out with the Torun 32 m radio telescope between June 2009 and April 2014. Flux density variations with period of 120 to 245 d were detected for some or all spectral features. A variability pattern with a fast rise and relatively slow fall on time-scale of 30-60 d dominated. A reverse pattern was observed for some features of G22.357+0.066, while sinusoidal-like variations were detected in G25.411+0.105. A weak burst lasting ~520 d with the velocity drift of 0.24 km/s/yr occurred in G22.357+0.066. For three sources for which high resolution maps are available, we found that the features with periodic behaviour are separated by more than 500 au from those without any periodicity. This suggests that the maser flares are not triggered by large-scale homogeneous variations in either the background seed photon fl...
Study of multi-periodic coronal pulsations during an X-class solar flare
Chowdhury, Partha; Dwivedi, B N; Sych, Robert; Moon, Y -J
2015-01-01
We investigate quasi-periodic coronal pulsations during the decay phase of an X 3.2 class flare on 14 May 2013, using soft X-ray data from the RHESSI satellite. Periodogram analyses of soft X-ray light curves show that 53 s and 72 s periods co-exist in the 3-6, 6-12 and 12-25 KeV energy bands. Considering the typical length of the flaring loop system and observed periodicities, we find that they are associated with multiple (first two harmonics) of fast magnetoacoustic sausage waves. The phase relationship of soft X-ray emissions in different energy bands using cross-correlation technique show that these modes are standing in nature as we do not find the phase lag. Considering the period ratio, we diagnose the local plasma conditions of the flaring region by invoking MHD seismology. The period ratio P1/2P2 is found to be 0.65, which indicates that such oscillations are most likely excited in longitudinal density stratified loops.
Short-period X-ray oscillations in super-soft novae and persistent SSS
Ness, J -U; Osborne, J P; Kuulkers, E; Henze, M; Piro, A L; Drake, J J; Dobrotka, A; Schwarz, G; Starrfield, S; Kretschmar, P; Hirsch, M; Wilms, J
2015-01-01
Transient short-period <100s oscillations have been found in the X-ray light curves of three novae during their SSS phase and in one persistent SSS. We pursue an observational approach to determine possible driving mechanisms and relations to fundamental system parameters such as the white dwarf mass. We performed a systematic search for short-period oscillations in all available XMM-Newton and Chandra X-ray light curves of persistent SSS and novae during their SSS phase. To study time evolution, we divided each light curve into short time segments and computed power spectra. We then constructed dynamic power spectra from which we identified transient periodic signals even when only present for a short time. From all time segments of each system, we computed fractions of time when periodic signals were detected. In addition to the previously known systems with short-period oscillations, RS Oph (35s), KT Eri (35s), V339 Del (54s), and Cal 83 (67s), we found one additional system, LMC 2009a (33s), and also c...
Oscillatory convective modes in red giants: a possible explanation of the long secondary periods
Saio, Hideyuki; Takayama, Masaki; Ita, Yoshifusa
2015-01-01
We discuss properties of oscillatory convective modes in low-mass red giants, and compare them with observed properties of the long secondary periods (LSPs) of semi-regular red giant variables. Oscillatory convective modes are very nonadiabatic g$^{-}$ modes and they are present in luminous stars, such as red giants with $\\log L/{\\rm L}_\\odot \\ga 3$. Finite amplitudes for these modes are confined to the outermost nonadiabatic layers, where the radiative energy flux is more important than the convective energy flux. The periods of oscillatory convection modes increase with luminosity, and the growth times are comparable to the oscillation periods. The LSPs of red giants in the Large Magellanic Cloud (LMC) are observed to lie on a distinct period-luminosity sequence called sequence D. This sequence D period-luminosity relation is roughly consistent with the predictions for dipole oscillatory convective modes in AGB models if we adopt a mixing length of 1.2 pressure scale height ($\\alpha = 1.2$). However, the ef...
Modification of the Carbon and Beryllium Walls in JET by Erosion, Redeposition and Deuterium Trapping after the 1991 Discharge Period
Broader source: Energy.gov [DOE]
Energy Efficiency Program for Residential Products: Energy Conservation Standards for Residential Dishwashers, Reopening of the Comment Period
MAP3S precipitation chemistry network. Third periodic summary report, July 1978-December 1979
Not Available
1980-05-01
The MAP3S Precipitation Chemistry Network consists of eight collection sites in the northeastern United States. Precipitation event samples are collected by cooperating site operators, using specially developed sampling equipment. In this, the third periodic summary report, are listed field and concentration data for the period July 1, 1978 to December 31, 1979. Over three years' samples have been collected at most of the sites, which went into operation between September 1976 and October 1978. Samples are chemically analyzed at a central laboratory for 13 pollutant species. Weekly samples in addition to event samples were collected over a 1 1/2 year period at three sites. Analysis of one year's results indicates that there is little difference between the concentrations collected by the two methods in terms of seasonal precipitation-weighted means for all species except dissolved SO/sub 2/. Event samples tend to average about 25% higher in SO/sub 2/ than weekly samples.
A study on periodic solutions for the circular restricted three-body problem
Gao, F. B. [School of Mathematical Science, Yangzhou University, Yangzhou 225002 (China); Zhang, W., E-mail: gaofabao@sina.com, E-mail: gaofabao@gmail.com [College of Mechanical Engineering, Beijing University of Technology, Beijing 100124 China (China)
2014-12-01
For the circular restricted three-body problem (CR3BP) in the inertial frame, we interpret the fact that there is no non-trivial 2?-periodic solution of the problem's homogeneous system. Furthermore, based on Reissig's theory, the existence of periodic solutions for the CR3BP is proved rigorously by using the above fact in conjunction with an a priori estimate. It is significant that the existence of periodic solutions of the CR3BP is mainly influenced by factors such as initial values, primary masses, and selection of the problem's control function. In addition, it is notable that the analytic proof of Poincaré's first class solutions is addressed for all values of the mass parameter in the interval (0, 1), the value of which must be sufficiently small according to previously published literature.
Broadband asymmetric acoustic transmission by a plate with quasi-periodic surface ridges
Li, Chunhui; Ke, Manzhu Ye, Yangtao; Xu, Shengjun; Qiu, Chunyin; Liu, Zhengyou
2014-07-14
In this paper, an acoustic system with broadband asymmetric transmission is designed and fabricated, which consists of a water-immersed aluminum plate engraved with quasi-periodically-patterned ridges on single surface. It demonstrates that when the acoustic waves are launched into the system from the structured side, they can couple into the Lamb modes in the plate efficiently and attain a high transmission; on the contrary, when the waves are incident from the opposite flat side, the coupling is weak, and the transmission is low. Superior to systems with periodic patterning, this quasi-periodically-patterned system has a broad working frequency range due to the collective contributions from the multiple diffractions specific to the structure.
Tonn, Bruce Edward; Rose, Erin M; Schmoyer, Richard L; Eisenberg, Joel Fred; Ternes, Mark P; Schweitzer, Martin; Hendrick, Timothy P
2012-08-01
This report describes the third major evaluation of the Program, encompassing program years 2009 to 2011. In this report, this period of time is referred to as the ARRA Period. This is a special period of time for the Program because the American Recovery and Reinvestment Act (ARRA) of 2009 has allocated $5 billion of funding for the Program. In normal program years, WAP s annual appropriation is in the range of $200-250 million, supporting the weatherization of approximately 100,000 homes. With the addition of ARRA funding during these program years, the expectation is that weatherization activity will exceed 300,000 homes per year. In addition to saving energy and reducing low-income energy bills, expanded WAP funding is expected to stimulate the economy by providing new jobs in the weatherization field and allowing low-income households to spend more money on goods and services by spending less on energy.
Periods and damping rates of fast sausage oscillations in multi-shelled coronal loops
Chen, Shao-Xia; Xia, Li-Dong; Yu, Hui
2015-01-01
Standing sausage modes are important in interpreting quasi-periodic pulsations in the lightcurves of solar flares. Their periods and damping times play an important role in seismologically diagnosing key parameters like the magnetic field strength in regions where flare energy is released. Usually such applications are based on theoretical results neglecting unresolved fine structures in magnetized loops. However, the existence of fine structuring is suggested on both theoretical and observational grounds. Adopting the framework of cold magnetohydrodynamics (MHD), we model coronal loops as magnetized cylinders with a transverse equilibrium density profile comprising a monolithic part and a modulation due to fine structuring in the form of concentric shells. The equation governing the transverse velocity perturbation is solved with an initial-value-problem approach, and the effects of fine structuring on the periods $P$ and damping times $\\tau$ of global, leaky, standing sausage modes are examined. A parameter...
Analysis and Control of Period-Doubling Bifurcation in Buck Converters Using Harmonic Balance
Chung-Chieh Fang; Eyad H. Abed
2012-10-27
Period doubling bifurcation in buck converters is studied by using the harmonic balance method. A simple dynamic model of a buck converter in continuous conduction mode under voltage mode or current mode control is derived. This model consists of the feedback connection of a linear system and a nonlinear one. An exact harmonic balance analysis is used to obtain a necessary and sufficient condition for a period doubling bifurcation to occur. If such a bifurcation occurs, the analysis also provides information on its exact location. Using the condition for bifurcation, a feedforward control is designed to eliminate the period doubling bifurcation. This results in a wider range of allowed source voltage, and also in improved line regulation.
Controlled motion of Janus particles in periodically phase-separating binary fluids
Takeaki Araki; Shintaro Fukai
2015-04-03
We numerically investigate the propelled motions of a Janus particle in a periodically phase-separating binary fluid mixture. In this study, the surface of the particle tail prefers one of the binary fluid components and the particle head is neutral in the wettability. During the demixing period, the more wettable phase is selectively adsorbed to the particle tail. Growths of the adsorbed domains induce the hydrodynamic flow in the vicinity of the particle tail, and this asymmetric pumping flow drives the particle toward the particle head. During the mixing period, the particle motion almost ceases because the mixing primarily occurs via diffusion and the resulting hydrodynamic flow is negligibly small. Repeating this cycle unboundedly moves the Janus particle toward the head. The dependencies of the composition and the repeat frequency on the particle motion are discussed.
Chemical Technology Division progress report for the period April 1, 1985 to December 31, 1986
Not Available
1987-08-01
This progress report summarizes the research and development efforts conducted in the Chemical Technology Division (Chem Tech) during the period April 1, 1985, through December 31, 1986. The following major areas are covered in the discussion: nuclear and chemical waste management, environmental control technology, basic science and technology, biotechnology research, transuranium-element processing, Nuclear Regulatory Commission programs, radioactive materials production, computer/engineering applications, fission energy, environmental cleanup projects, and various other work activities. As an appendix, the Administrative Summary presents a comprehensive compilation of publications, oral presentations, awards and recognitions, and patents of Chem Tech staff members during this report period. An organization chart, a staffing level and financial summary, and lists of seminars and Chem Tech consultants for the period are also included to provide additional information. 78 figs., 40 tabs.
Christopher Beetle; Benjamin Bromley; Richard H. Price
2006-02-08
The periodic standing wave approach to binary inspiral assumes rigid rotation of gravitational fields and hence helically symmetric solutions. To exploit the symmetry, numerical computations must solve for ``helical scalars,'' fields that are functions only of corotating coordinates, the labels on the helical Killing trajectories. Here we present the formalism for describing linearized general relativity in terms of helical scalars and we present solutions to the mixed partial differential equations of the linearized gravity problem (and to a toy nonlinear problem) using the adapted coordinates and numerical techniques previously developed for scalar periodic standing wave computations. We argue that the formalism developed may suffice for periodic standing wave computations for post-Minkowskian computations and for full general relativity.
Oscar P. Bruno; Stephen P. Shipman; Catalin Turc; Stephanos Venakides
2013-07-04
We present efficient methods for computing wave scattering by diffraction gratings that exhibit two-dimensional periodicity in three dimensional (3D) space. Applications include scattering in acoustics, electromagnetics and elasticity. Our approach uses boundary-integral equations. The quasi-periodic Green function is a doubly infinite sum of scaled 3D free-space outgoing Helmholtz Green functions. Their source points are located at the nodes of a periodicity lattice of the grating. For efficient numerical computation of the lattice sum, we employ a smooth truncation. Super-algebraic convergence to the Green function is achieved as the truncation radius increases, except at frequency-wavenumber pairs at which a Rayleigh wave is at exactly grazing incidence to the grating. At these "Wood frequencies", the term in the Fourier series representation of the Green function that corresponds to the grazing Rayleigh wave acquires an infinite coefficient and the lattice sum blows up. At Wood frequencies, we modify the Green function by adding two types of terms to it. The first type adds weighted spatial shifts of the Green function to itself with singularities below the grating; this yields algebraic convergence. The second-type terms are quasi-periodic plane wave solutions of the Helmholtz equation. They reinstate (with controlled coefficients) the grazing modes, effectively eliminated by the terms of first type. These modes are needed in the Green function for guaranteeing the well-posedness of the boundary-integral equation that yields the scattered field. We apply this approach to acoustic scattering by a doubly periodic 2D grating near and at Wood frequencies and scattering by a doubly periodic array of scatterers away from Wood frequencies.
B. Subash; V. K. Chandrasekar; M. Lakshmanan
2013-04-03
Considering an array of spin torque transfer nano oscillators (STNOs), we have investigated the synchronization property of the system under the action of a common periodically driven applied external magnetic field by numerically analyzing the underlying system of Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equations for the macro-spin variables. We find the novel result that the applied external magnetic field can act as a medium to induce synchronization of periodic oscillations, both in-phase and anti-phase, even without coupling through spin current, thereby leading to the exciting possibility of enhancement of microwave power in a straightforward way.
Quantum spatial-periodic harmonic model for daily price-limited stock markets
Meng, Xiangyi; Xu, Jingjing; Guo, Hong
2015-01-01
We investigate the behavior of stocks in daily price-limited stock markets by purposing a quantum spatial-periodic harmonic model. The stock price is presumed to oscillate and damp in a quantum spatial-periodic harmonic oscillator potential well. Complicated non-linear relations including inter-band positive correlation and intra-band negative correlation between the volatility and the trading volume of stocks are derived by considering the energy band structure of the model. The validity of price limitation is then examined and abnormal phenomena of a price-limited stock market (Shanghai Stock Exchange) of China are studied by applying our quantum model.
Periodic magnetic structures generated by spin–polarized currents in nanostripes
Volkov, Oleksii M. Sheka, Denis D.; Kravchuk, Volodymyr P.; Gaididei, Yuri; Mertens, Franz G.
2013-11-25
The influence of a transverse spin–polarized current on long ferromagnetic nanostripes is studied numerically. The magnetization behavior is analyzed for all range of the applied currents, up to the saturation. It is shown that the saturation current is a nonmonotonic function of the stripe width. A number of stable periodic magnetization structures are observed below the saturation. Type of the periodical structure depends on the stripe width. Besides the one–dimensional domain structure, typical for narrow wires, and the two–dimensional vortex–antivortex lattice, typical for wide films, a number of intermediate structures are observed, e.g., cross–tie and diamond state.
Oceanography of Accreting Neutron Stars: Non-Radial Oscillations and Periodic X-Ray Variability
Lars Bildsten; Andrew Cumming; Greg Ushomirsky; Curt Cutler
1997-12-31
Observations of quasi-periodic oscillations (QPOs) in the luminosity from many accreting neutron stars (NS) have led us to investigate a source of periodicity prevalent in other stars: non-radial oscillations. After summarizing the structure of the atmosphere and ocean of an accreting NS, we discuss the various low l g-modes with frequencies in the 1-100 Hz range. Successful identification of a non-radial mode with an observed frequency would yield new information about the thermal and compositional makeup of the NS, as well as its radius. We close by discussing how rapid rotation changes the g-mode frequencies.
QUASI-PERIODICITIES OF THE BL LACERTAE OBJECT PKS 2155–304
Sandrinelli, A.; Treves, A. [Università degli Studi dell' Insubria, Via Valleggio 11, I-22100 Como (Italy); Covino, S., E-mail: asandrinelli@yahoo.it [INAF-Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, I-23807 Merate (Italy)
2014-09-20
We have searched for periodicities in our VRIJHK photometry of PKS 2155–304, which covers the years 2005-2012. A peak of the Fourier spectrum with high significance is found at T ? 315 days, confirming the recent findings by Zhang et al. The examination of the gamma-ray light curves from the Fermi archives yields a significant signal at ?2T, which, while nominally significant, involves data spanning only ?6T. Assuming a black hole mass of 10{sup 9} M {sub ?}, the Keplerian distance corresponding to the quasi-period T is ?10{sup 16} cm, about 50 Schwarzschild radii.
The quasi-periodic nature of wall slip for molten plastics in large amplitude oscillatory shear
Adrian, David Warren
1992-01-01
is not to be confused with a quasi-periodic spectrum like Figure 15 because of its strong continuous component. 0. 01 X 0. 001 0. 0001 0. 2 0. 4 0. 6 f (Hz) Figure 14. Chaotic amplitude spectrum of Duffing's equation. 0. 1 0. 01 X 0. 001 0. 0001 1E-05 0... amplitude spectrum for a viscoelastic melt in LAOS 6. Pipkin diagram, adapted from Dealy and Wissbrun (1990), 14 showing the regimes of oscillatory shear for a viscoelastic melt . . . . 15 7. Time domain plot of the quasi-periodic forced van der Pol...
Shi, Xuesong; Jiang, Lan; Li, Xin, E-mail: lixin02@bit.edu.cn; Zhang, Kaihu; Yu, Dong; Yu, Yanwu [NanoManufacturing Fundamental Research Joint Laboratory of National Science Foundation of China, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Lu, Yongfeng [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States)
2014-07-21
The dependence of periodic structures and ablated areas on temporal pulse shaping is studied upon irradiation of fused silica by femtosecond laser triple-pulse trains. Three types of periodic structures can be obtained by using pulse trains with designed pulse delays, in which the three-dimensional nanopillar arrays with ?100–150?nm diameters and ?200?nm heights are first fabricated in one step. These nanopillars arise from the break of the ridges of ripples in the upper portion, which is caused by the split of orthogonal ripples in the bottom part. The localized transient electron dynamics and corresponding material properties are considered for the morphological observations.
Complete Chaotic Mixing in an Electro-osmotic Flow by Destabilization of Key Periodic Pathlines
R. Chabreyrie; C. Chandre; P. Singh; N. Aubry
2011-02-07
The ability to generate complete, or almost complete, chaotic mixing is of great interest in numerous applications, particularly for microfluidics. For this purpose, we propose a strategy that allows us to quickly target the parameter values at which complete mixing occurs. The technique is applied to a time periodic, two-dimensional electro-osmotic flow with spatially and temporally varying Helmoltz-Smoluchowski slip boundary conditions. The strategy consists of following the linear stability of some key periodic pathlines in parameter space (i.e., amplitude and frequency of the forcing), particularly through the bifurcation points at which such pathlines become unstable.
Los Alamos National Laboratory's Chemistry Division Presents Periodic Table of the Elements
Hochberg, Michael
144.2 61 Pm (147) 62 Sm 150.4 63 Eu 152.0 64 Gd 157.3 65 Tb 158.9 66 Dy 162.5 67 Ho 164.9 68 Er 167.lanl.gov/periodic/ (1 of 3) [5/17/2001 4:06:20 PM] #12;Lanthanide Series* 58 Ce 140.1 59 Pr 140.9 60 Nd) [5/17/2001 4:06:20 PM] #12;about this resource A Periodic Table of the Elements at Los Alamos
Periodic striations on beryllium and tungsten surfaces by indirect femtosecond laser irradiation
Lungu, C. P.; Tico?, C. M., E-mail: catalin.ticos@inflpr.ro; Poro?nicu, C.; Jepu, I.; Lungu, M.; Marcu, A.; Luculescu, C.; Cojocaru, G.; Ursescu, D.; B?nici, R.; Ungureanu, G. R. [National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest (Romania)] [National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest (Romania)
2014-03-10
Femtosecond laser pulses with ??=?800?nm were focused in air at one atmosphere and in deuterium (D) at low pressure. Submicron periodic structures were observed on surfaces made of Be, W and a mixture of Be-W immersed in these gases and placed nearly parallel with the laser beam, at 300??m from the focal spot. In air, no structures were observed on Be. For the Be-W mixture, the periodic structures were uniform and parallel when formed in D but irregular in air. In this last case the striations were organized into small patches of 1 to 2 ?m in size.
Joseph M. Starobin; Vivek Varadarajan
2011-06-02
We analyze the effects of spatially extended periodic forcing on the dynamics of one-dimensional excitation waves. Entrainment of unstable primary waves has been studied numerically for different amplitudes and frequencies of additional sub-threshold stimuli. We determined entrainment regimes under which excitation blocks were transformed into consistent 1:1 responses. These responses were spatially homogeneous and synchronized in the entire excitable medium. Compared to primary pulses, pulses entrained by secondary stimulations were stable at considerably shorter periods which decreased at higher amplitudes and greater number of secondary stimuli. Our results suggest a practical methodology for stabilization of excitation in reaction-diffusion media with regions of reduced excitability.
Three New Long Period X-ray Pulsars Discovered in the Small Magellanic Cloud
D. J. Macomb; D. W. Fox; R. C. Lamb; T. A. Prince
2003-01-04
The Small Magellanic Cloud is increasingly an invaluable laboratory for studying accreting and isolated X-ray pulsars. We add to the class of compact SMC objects by reporting the discovery of three new long period X-ray pulsars detected with the {\\it Chandra X-ray Observatory}. The pulsars, with periods of 152, 304 and 565 seconds, all show hard X-ray spectra over the range from 0.6 - 7.5 keV. The source positions of the three pulsars are consistent with known H-alpha emission sources, indicating they are likely to be Be type X-ray binary star systems.
JOURNAL DE PHYSIQUE IV Colloque C9, supplCmentau Journal de Physique III, Volume 4, novembre 1994
Boyer, Edmond
beamline (ID6) whose source is a high beta undulator (px=27m, Pz=13m). 2. SINGLELENS EXPERIMENTS 2.1 Setup. 3. HIGH ENERGY X-RAY TELESCOPE We used a 42mm-period undulator on the first harmonic (gap=45mm). The high energy x-ray telescope setup based on two circular BFL is presented in Fig.2. We used Si-444
Broader source: Energy.gov [DOE]
This report provides the results of a review conducted by the Office of Nuclear Safety (AU-30) of the implementation of periodic Natural Phenomena Hazards (NPH) assessment reviews by sites reporting to the National Nuclear Security Administration (NNSA), and the Offices of Environmental Management, Nuclear Energy, and Science.
Battery Aware Dynamic Scheduling For Periodic Task Graphs Venkat Rao1
Navet, Nicolas
Battery Aware Dynamic Scheduling For Periodic Task Graphs Venkat Rao1 , Nicolas Navet1 , Gaurav Of Technology, Delhi 4 Indian Institute Of Technology, Delhi Dept. of Computer Science and Engineering Dept. of Electrical Engineering anshul@cse.iitd.ernet.in gswaran@ee.iitd.ernet.in Abstract Battery lifetime, a primary
Performance Analysis of Periodic Busy Tones Protecting a ZigBee Network from Wi-Fi
Bahk, Saewoong
Performance Analysis of Periodic Busy Tones Protecting a ZigBee Network from Wi-Fi Interruption--Generating a busy tone is known as a good solution that enables a ZigBee network to coexist with any Wi-Fi network in the same ISM band. To generate a busy tone, ZigBee networks need to deploy a signaler that transmits
Climate effects on the flight period of Lycaenid butterflies in Massachusetts
Williams, Ernest H.
Climate effects on the flight period of Lycaenid butterflies in Massachusetts Caroline A. Polgar a 2012 Accepted 16 December 2012 Keywords: Phenology Butterflies Climate change Museum records Citizen science a b s t r a c t The effect of climate change on the phenology of plants and birds of eastern North
Hopf bifurcations to quasi-periodic solutions for the two-dimensional plane Poiseuille flow
Barcelona, Universitat de
the branch of periodic flows which are born at the Hopf bifurcation of the laminar flow. It is known that topics in fluid mechanics. Poiseuille as well as Taylor Couette flow are test problems where of their geometry. The dynamics of plane Poiseuille flow departs from the laminar flow. The stability of the laminar
Copyright 2009 by ASME Laminar fully developed flow in streamwise-periodic
Bahrami, Majid
1 Copyright ©2009 by ASME ABSTRACT Laminar fully developed flow in streamwise-sections [1-5]. It has been experimentally and numerically observed that the entrance lengths of fluid flow theoretical works for such ducts often focus on the periodically fully-developed fluid flow and heat transfer
Modeling the Coastal Ocean over a Time Period of Several April 8, 2008
Frénod, Emmanuel
, lost objects or oil spill over long periods of time in near coastal ocean areas. Such methods would. The final target of this program is to develop methods to forecast the drift of things like con- tainers be of interest for services in charge of maritime safety, environmental studies or pollution impact assessment
Periodicity detection and localization using spike timing from the AER EAR
Liu, Shih-Chii
Periodicity detection and localization using spike timing from the AER EAR Theodore Yu1 , Andrew Event Representation (AER) where each spike carries the identity of the sender. There are a handful of silicon cochleae with an Address Event type representation [4][5][6][7]. The AER EAR chip that we use
POSSIBLE DISINTEGRATING SHORT-PERIOD SUPER-MERCURY ORBITING KIC 12557548
Chiang, E.
We report on the discovery of stellar occultations, observed with Kepler, which recur periodically at 15.685 hr intervals, but which vary in depth from a maximum of 1.3% to a minimum that can be less than 0.2%. The star ...
Spatial periodicity in growth plate shear mechanical properties is disrupted by vitamin D deficiency
Cohen, Itai
Spatial periodicity in growth plate shear mechanical properties is disrupted by vitamin D modulus Vitamin D a b s t r a c t The growth plate is a highly organized section of cartilage in the long disruption caused by a dietary deficiency of vitamin D. The shear mechanical properties of the proximal
Weekly Security Incident Log Period of Aug 12 -Aug 18, 2013
2013-001248 THOMPSON ROAD Gas leak Security , Toronto Fire, Toronto Police, and Occupational Health and Safety responded to a report of a natural gas leak in the area of the Life Science BuildingWeekly Security Incident Log Period of Aug 12 - Aug 18, 2013 Incident No. Reported Date Building
Weekly Security Incident Log Period of Feb 6 -Feb 12, 2012
Gas leak Security and Toronto Fire responded to a report of a natural gas odour in B-wing. TorontoWeekly Security Incident Log Period of Feb 6 - Feb 12, 2012 Incident No. Reported Date Building\\Const. Security, York Fire Prevention and Toronto Fire responded to a fire alarm. The cause of the alarm
Weekly Security Incident Log Period of Jul 9 -Jul 15, 2012
and Safety responded to a report of a natural gas odour in the building. The building was checked and no natural gas was found. Toronto Fire determined that all was in order. 7/12/2012 07:31 AM HazardousWeekly Security Incident Log Period of Jul 9 - Jul 15, 2012 Incident No. Reported Date Building
Weekly Security Incident Log Period of Apr 29 -May 5, 2013
2013-000845 YORK LANES RETAIL Gas leak Security, Toronto Fire and Enbridge Gas responded to a report of a natural gas odour in the building. The source of the odour was located in a restaurant kitchen. EnbridgeWeekly Security Incident Log Period of Apr 29 - May 5, 2013 Incident No. Reported Date Building
Lisbon, University of
Regeneration · Shape Optimization · Topology Optimization · Auxetic Materials 1 Introduction The main of the effective material are optimized by minimizing a cost functional (6) under a volume constraintShape and Topology Optimization for Periodic Problems Part II: Optimization algorithm and numerical
Sound transmission through a periodic cascade with application to drill pipes
Rienstra, Sjoerd W.
Sound transmission through a periodic cascade with application to drill pipes Niels J. C. Lous Acoustical data transmission through the wall of drill pipes is considered. Drill pipes are known to behave the frequency domain drill pipe models presented by Barnes and Kirkwood J. Acoust. Soc. Am. 51, 16061608 1972
An analytic approximation to the Diffusion Coefficient for the periodic Lorentz Gas
C. Angstmann; G. P. Morriss
2012-02-14
An approximate stochastic model for the topological dynamics of the periodic triangular Lorentz gas is constructed. The model, together with an extremum principle, is used to find a closed form approximation to the diffusion coefficient as a function of the lattice spacing. This approximation is superior to the popular Machta and Zwanzig result and agrees well with a range of numerical estimates.
Distributed Multi-Period Optimal Power Flow for Demand Response in Microgrids
Yeoh, William
Distributed Multi-Period Optimal Power Flow for Demand Response in Microgrids Paul Scott1 direction method of multipliers (ADMM), can be adapted to remain practical in this challenging microgrid discrete decisions. Our experiments on a suburb-sized microgrid show that the AC power flows and a simple
South Carolina graduates are getting jobs. Even in a period that the American Bar Association
Almor, Amit
South Carolina graduates are getting jobs. Even in a period that the American Bar Association paths in the law, sponsor a yearly"Career Week" with South Carolina law alumni each spring, offer a mock/non-profit 3 Business 37 $32,000-$105,000 Academic 2 not available 2012 South Carolina Bar Passage Rate 153
Real-time Scheduling of periodic tasks in a monoprocessor system with rechargeable energy storage
Paris-Sud XI, Université de
Real-time Scheduling of periodic tasks in a monoprocessor system with rechargeable energy storage-time computing system that is powered through a renewable energy storage device. In this context, two constraints for the properties of the energy source, capacity of the energy storage as well as energy consumption of the tasks
Periodic Communication Logics for the Decentralized Control of Multi-Agent Systems
Lemmon, Michael
Periodic Communication Logics for the Decentralized Control of Multi-Agent Systems Yashan Sun decision is not related to the current state of the system. We say the communication logic is closed and Michael D. Lemmon Abstract-- This paper studies a system consisting of several dynamical subsystems
Almost Periodic Passive Tracer Dispersion \\Lambda Hongjun Gao 1 , Jinqiao Duan 2 and Xinchu Fu 3
Almost Periodic Passive Tracer Dispersion \\Lambda Hongjun Gao 1 , Jinqiao Duan 2 and Xinchu Fu 3 1 the impact of external sources on the patÂ tern formation of concentration profiles of passive tracers Science Foundation Grant DMSÂ 9704345 and the UK EPSRC Grant GR/M36335. 1 #12; Key words: Passive tracer
SPECTRAL DISTRIBUTIONS OF DIFFUSE AND GLOBAL IRRADIANCE FOR CLEAR AND CLOUDY PERIODS
Oregon, University of
SPECTRAL DISTRIBUTIONS OF DIFFUSE AND GLOBAL IRRADIANCE FOR CLEAR AND CLOUDY PERIODS Gina@uoregon.edu ABSTRACT An LI1800 Portable Spectroradiometer is used to measure solar spectral irradiance for solar showing global horizontal and diffuse irradiance for clear and cloudy days, and then used
Periodic equivalence ratio modulation method and apparatus for controlling combustion instability
Richards, George A. (Morgantown, WV); Janus, Michael C. (Baltimore, MD); Griffith, Richard A. (Morgantown, WV)
2000-01-01
The periodic equivalence ratio modulation (PERM) method and apparatus significantly reduces and/or eliminates unstable conditions within a combustion chamber. The method involves modulating the equivalence ratio for the combustion device, such that the combustion device periodically operates outside of an identified unstable oscillation region. The equivalence ratio is modulated between preselected reference points, according to the shape of the oscillation region and operating parameters of the system. Preferably, the equivalence ratio is modulated from a first stable condition to a second stable condition, and, alternatively, the equivalence ratio is modulated from a stable condition to an unstable condition. The method is further applicable to multi-nozzle combustor designs, whereby individual nozzles are alternately modulated from stable to unstable conditions. Periodic equivalence ratio modulation (PERM) is accomplished by active control involving periodic, low frequency fuel modulation, whereby low frequency fuel pulses are injected into the main fuel delivery. Importantly, the fuel pulses are injected at a rate so as not to affect the desired time-average equivalence ratio for the combustion device.
A Novel Global Op-miza-on Approach to the Mul-period Blending Problem
Grossmann, Ignacio E.
Overall Flows Individual Components (Blending) · Flow/Inventory Bounds · OperaA Novel Global Op-miza-on Approach to the Mul-period Blending Problem Sco · Minimize total cost of blending opera-on Fs3,t Cs3 Fs2,t Cs2 Fd1,t CL d1-CU d1
Risk neutral valuation of options in multi-period discrete-time markets
Risk neutral valuation of options in multi- period discrete-time markets In this lecture we study is the discounted expectation of its payoff under a martingale measure and use it to price call and put options Let F be an algebra of subsets of the finite sample space . Definition. A real-valued function (or
Solid State Division progress report for period ending March 31, 1992
Green, P.H.; Hinton, L.W. [eds.
1992-09-01
During this period, the division conducted a broad, interdisciplinary materials research program with emphasis on theoretical solid state physics, superconductivity, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. The High Flux Isotope Reactor was returned to full operation.
Wright, Angela Shanna
2004-01-01
/Lo), linseed oil (Hi/Lo), low (Lo/Mod) or high (Lo/Hi) menhaden fish oil. Plasma was collected on days 0, 3, 7, 14, 28, 42, and 56 of gestation, days 10 and 28 of lactation, and days 4, 10, 16, 28, 70, and 84 of the neonatal period. Electrophoresis was run...
Solid State Division progress report for period ending September 30, 1990
Green, P.H.; Hinton, L.W.
1991-03-01
This report covers research progress in the Solid State Division from April 1, 1989, to September 30, 1990. During this period, division research programs were significantly enhanced by the restart of the High-Flux Isotope Reactor (HFIR) and by new initiatives in processing and characterization of materials.
Tunable optical fiber devices based on broadband long-period gratings and pumped microfluidics
Rogers, John A.
Tunable optical fiber devices based on broadband long-period gratings and pumped microfluidics; accepted 8 October 2003 This letter describes classes of tunable microfluidic fiber FF devices that use spectral range. Dynamic tuning is achieved by electrowetting-based pumping of microfluidic plugs back
Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana, E-mail: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)
2014-09-21
In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C?H?OH) and water (H?O) using linearly polarized Ti:sapphire fs laser pulses of ~110 fs pulse duration and ~800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.
LARGE TORSIONAL OSCILLATIONS IN A SUSPENSION BRIDGE: MULTIPLE PERIODIC SOLUTIONS TO A NONLINEAR
Moore, Kristen
of the Tacoma Narrows Bridge, we solve the damped equation numerically and observe that multiple periodic the dramatic and finally destructive torsional oscillations of the Tacoma Narrows Bridge that preceded its observed on the Tacoma Narrows and other suspension bridges. Theoretical and numerical evidence to support
Periodic equivalence ratio modulation method and apparatus for controlling combustion instability
Richards, G.A.; Janus, M.C.; Griffith, R.A.
2000-05-09
The periodic equivalence ratio modulation (PERM) method and apparatus significantly reduces and/or eliminates unstable conditions within a combustion chamber. The method involves modulating the equivalence ratio for the combustion device, such that the combustion device periodically operates outside of an identified unstable oscillation region. The equivalence ratio is modulated between preselected reference points, according to the shape of the oscillation region and operating parameters of the system. Preferably, the equivalence ratio is modulated from a first stable condition to a second stable condition, and, alternatively, the equivalence ratio is modulated from a stable condition to an unstable condition. The method is further applicable to multi-nozzle combustor designs, whereby individual nozzles are alternately modulated from stable to unstable conditions. Periodic equivalence ratio modulation (PERM) is accomplished by active control involving periodic, low frequency fuel modulation, whereby low frequency fuel pulses are injected into the main fuel delivery. Importantly, the fuel pulses are injected at a rate so as not to affect the desired time-average equivalence ratio for the combustion device.
Modeling Alveolar Volume Changes During Periodic Breathing in Heterogeneously Ventilated Lungs
Jeavons, Peter
Modeling Alveolar Volume Changes During Periodic Breathing in Heterogeneously Ventilated Lungs SARA-uniform breathing pattern for a lung with an inhomogeneous gas distribution, such as that observed in some subjects of irregular breathing caused by small, poorly ventilated regions of the lung. Presented here is an extension
Multi-period Optimal Procurement and Demand Responses in the Presence of Uncertain Supply
Wierman, Adam
Multi-period Optimal Procurement and Demand Responses in the Presence of Uncertain Supply Libin markets, uncertainty in renewable generation, and real-time dynamic demand response. A load-serving entity day-ahead decision, propose real-time demand response algorithm, and study the effect of volume
Distributed Multi-Period Optimal Power Flow for Demand Response in Microgrids
Trumpf, Jochen
Distributed Multi-Period Optimal Power Flow for Demand Response in Microgrids Paul Scott Methodologies]: Artificial Intelligence Keywords OPF; ADMM; demand response; distributed control; micro- grid-coupled behaviours. In this new regime demand response (DR) techniques will play a central role in providing
A Periodic Portfolio Scheduler for Scientific Computing in the Data Center
Feitelson, Dror
A Periodic Portfolio Scheduler for Scientific Computing in the Data Center Kefeng Deng1,2 , Ruben.S.Verboon@student.tudelft.nl, A.Iosup@tudelft.nl Abstract. The popularity of data centers in scientific computing has led to new of efficient scheduling algorithms for the data center is an increasingly costlier and more difficult challenge
Boyer, Edmond
Generation of polarization-entangled photons using type-II doubly periodically poled lithium the issue of the generation of non-degenerate cross-polarization-entangled photon pairs using type-conversion processes, namely ordinary pump photon down- conversion to either extraordinary signal and ordinary idler
A Low-Power Acoustic Periodicity Detector Chip for Voice and Engine Detection
Horiuchi, Timothy K.
designed a simple, low-power (1.5 Wµ ) analog VLSI circuit that detects periodicity in the time. This algorithm rejects impulse events, wind noise, and is intensity- independent. Clearly, as this type into the chip to a peak-detector/spike-generator circuit. The `spike generator' generates a voltage spike
THE INCREASING ROTATION PERIOD OF COMET 10P/TEMPEL 2
Knight, Matthew M.; Schleicher, David G. [Lowell Observatory, 1400 W. Mars Hill Rd, Flagstaff, AZ 86001 (United States); Farnham, Tony L. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Schwieterman, Edward W., E-mail: knight@lowell.ed [Physics and Space Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901 (United States)
2011-01-15
We imaged comet 10P/Tempel 2 on 32 nights from 1999 April through 2000 March. R-band light curves were obtained on 11 of these nights from 1999 April through 1999 June, prior to both the onset of significant coma activity and perihelion. Phasing of the data yields a double-peaked light curve and indicates a nucleus rotational period of 8.941 {+-} 0.002 hr with a peak-to-peak amplitude of {approx}0.75 mag. Our data are sufficient to rule out all other possible double-peaked solutions as well as the single- and triple-peaked solutions. This rotation period agrees with one of five possible solutions found in post-perihelion data from 1994 by Mueller and Ferrin (Icarus, 123, 463-477) and unambiguously eliminates their remaining four solutions. We applied our same techniques to published light curves from 1988 which were obtained at an equivalent orbital position and viewing geometry as in 1999. We found a rotation period of 8.932 {+-} 0.001 hr in 1988, consistent with the findings of previous authors and incompatible with our 1999 solution. This reveals that Tempel 2 spun-down by {approx}32 s between 1988 and 1999 (two intervening perihelion passages). If the spin-down is due to a systematic torque, then the rotation period prior to perihelion during the 2010 apparition is expected to be an additional 32 s longer than in 1999.
the past 150-year period of reported global Second, historical information on solar
compared with the radia- tive relaxation time of layers storing the heat blocked by sunspots. This timethe past 150-year period of reported global warming. Second, historical information on solar increase in solar activity beyond present levels might make the sun dimmer, decreasing its average out- put
A PERIOD-BASED GROUP MEMBERSHIP STRATEGY FOR NODES OF TDMA NETWORKS
Koopman, Philip
In automotive embedded systems, all nodes are not created equal. Automotive embedded systems generally have different periods. Current automotive buses such as the Controller Area Network (CAN) use a priority in order to provide a more predictable platform for safety assurance. Time Division Multiple Access (TDMA
Covariation of coastal water temperature and microbial pollution at interannual to tidal periods
Winant, Clinton D.
Covariation of coastal water temperature and microbial pollution at interannual to tidal periods. G. Monismith (2004), Covariation of coastal water temperature and microbial pollution at interannual the relationship between water temperature and fecal pollution in the surf zone at Huntington and Newport Beach
Lynch-Stieglitz, Jean
as freely meandering jet in the open ocean. On a basin- wide scale, the Gulf Stream separation latitudePersistence of Gulf Stream separation during the Last Glacial Period: Implications for current at which the Gulf Stream separated from the western boundary of the Atlantic Ocean in the past. The modern
A biped static balance control and torque pattern learning under unknown periodic external forces
Ito, Satoshi
A biped static balance control and torque pattern learning under unknown periodic external forces balancing task in which an unknown external force is exerted, using so-called `ankle strategy' model. When an external force is pe- riodic, a human adaptively maintains the balance, next learns how much force should
Proceedings Published 2007 by the American Chemical Society Double Direct Templating of Periodically
Braun, Paul
and sacrificial core etching. 3a, 4 Significant efforts are similarly focused on the synthesis of inorganic of Periodically Nanostructured Inorganic Hollow Microspheres Paul V. Braun, Alejandro Wolosiuk, Dongyeon Son, Dara V. Gough University of Illinois, Department of Materials Science and Engineering, Beckman Institute
Autophagic response of higher plant cells to a prolonged period of sucrose deprivation
Paris-Sud XI, Université de
, sudden temperature drop, water stress or the decrease of the circadian light period diminishes the rates in 3! P nuclear magnetic resonance (NMR) experi- ments. Cells harvested from the culture medium were acid (PCA) extraction (Roby et aL, 1987), sucrose and starch determi- nations (Journet et al., 1986
FILAMENT DISAPPEARANCES DURING THE PERIOD OF SEPTEMBER 1991 THROUGH SEPTEMBER 1994
FILAMENT DISAPPEARANCES DURING THE PERIOD OF SEPTEMBER 1991 THROUGH SEPTEMBER 1994 HAIMIN WANG1 of the disappearing solar filaments based on this set of data are made: (1) The disk latitude distribution of all larger disappearing filaments with a minimum length of 70 arc sec, including the time
Capacity Planning in a General Supply Chain with Multiple Contract Types Single Period Model
Graves, Stephen C.
and sufficient capacity to meet market demands. However, capacity planning is a very challenging task for manyCapacity Planning in a General Supply Chain with Multiple Contract Types Single Period Model Xin Huang · Stephen C. Graves Department of Electrical Engineering and Computer Science, Massachusetts
STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1
Volinsky, Alex A.
STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1 , Neville R. Moody2 applied stresses in thin films can cause film fracture. In the case of compressive stress thin film stress a network of through- thickness cracks forms in thin films. Excessive biaxial residual stress
Spectral theory for a class of periodically perturbed unbounded Jacobi matrices: elementary methods
Spectral theory for a class of periodically perturbed unbounded Jacobi matrices: elementary methods of his 80th birthday Abstract We use elementary methods to give a full characterization of the spectral properties of unbounded Jacobi matrices with zero diagonal and o#Âdiagonal entries of the type # n = n # + c
Dunin-Borkowski, Rafal E.
Nanotubes Vincent Jourdain,*,, Edward T. Simpson,§ Matthieu Paillet, Takeshi Kasama,§,| Rafal E. Dunin Form: April 22, 2006 We demonstrate the use of sequential catalytic growth to encapsulate iron, nickel-iron, and iron-cobalt phosphide catalyst nanoparticles periodically along the entire lengths of carbon nanotubes
Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
Barsotti, Lisa
This paper presents results of an all-sky search for periodic gravitational waves in the frequency range [50,1?190]??Hz and with frequency derivative range of ?[-20,1.1]×10[superscript -10]??Hz?s[superscript -1] for the ...
Quarterly RCRA Groundwater Monitoring Data for the Period April Through June 2006
Hartman, Mary J.
2006-11-01
This report provides information about RCRA groundwater monitoring for the period April through June 2006. Seventeen RCRA sites were sampled during the reporting quarter. Sampled sites include seven monitored under groundwater indicator evaluation (''detection'') programs, eight monitored under groundwater quality assessment programs, and two monitored under final-status programs.
Investigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses
Nikogosyan, David N.
efficiency with that for other existing meth- ods of recording. We studied the temperature sensing properties changes in the fiber core induced by thermal heating, were developed. They include the use of a CO2 laserInvestigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses
Small angle neutron scattering on periodically deformed polymers A. R. Rennie
Boyer, Edmond
765 Small angle neutron scattering on periodically deformed polymers A. R. Rennie Institut für Phys-768 SEPTEMBRE 1984, 1. Introduction. Neutron scattering has proved a useful tool for the investigation of a wide time for a small angle neutron scattering spectrum is several minutes. Obser- vation on rapidly
An analysis of tomb reliefs depicting boat construction from the Old Kingdom period in Egypt
Rogers, Edward Morgan
1996-01-01
Among the aspects of daily life represented on the walls of private tombs during the Old Kingdom in Egypt are reliefs depicting the construction of boat hulls. Examination of the twenty known reliefs and relief fragments which date to this period...
Linares, M.
We present a comprehensive study of the thermonuclear bursts and millihertz quasi-periodic oscillations (mHz QPOs) from the neutron star (NS) transient and 11 Hz X-ray pulsar IGR J17480–2446, located in the globular cluster ...
Barua, Rajeev
, and chemical content to enable precise application of agents such as water, fertilizer, and pesticideContention-Free Periodic Message Scheduler Medium Access Control in Wireless Sensor / Actuator implemented with a contention-free message scheduler. A message scheduler is used to determine which message
Barcelona, Universitat de
Periodic orbits and stability islands in chaotic seas created by separatrix crossings in slowÂfast systems Anatoly Neishtadt 1 , Carles Simâ??o 2 , Dmitri Treschev 3 , and Alexei Vasiliev 1 1 Space Research, Gubkina 8, Moscow 119991, Russia. Abstract We consider a 2 d.o.f. natural Hamiltonian system with one
Lithographically induced self-assembly of periodic polymer micropillar Stephen Y. Choua)
importance to science and technology. Technologi- cally, self-assembly promises not only low cost and highLithographically induced self-assembly of periodic polymer micropillar arrays Stephen Y. Choua by placing a second plate called a mask a distance above the polymer film. The pillars, formed by rising
Subsidence in the Michigan basin produced ~5 km of sedimentation over a period of more
other cra- tonic settings, such as the Illinois, Paris, and North Sea basins (Heidlauf et al., 1986ABSTRACT Subsidence in the Michigan basin produced ~5 km of sedimentation over a period of more corrections and estimates of paleo- bathymetry, we recognize four different styles of subsidence in the basin
MULTI-PERIOD CAPACITY PLANNING FOR INTEGRATED PRODUCT-PROCESS DESIGN
Saitou, Kazuhiro "Kazu"
MULTI-PERIOD CAPACITY PLANNING FOR INTEGRATED PRODUCT-PROCESS DESIGN Emre Kazancioglu Department-process design, robust design, capacity plan- ning, discrete event simulation, Monte Carlo simula- tion, multi increas- ing product quality by investing on higher quality machinery drives the price of the product up
A Numerical Method for Computing Time-Periodic Solutions in Dissipative Wave Systems
Yang, Jianke
. Then this equation is computed in the combined spatiotemporal domain as a boundary value problem by Newton:420455 C 2015 Wiley Periodicals, Inc., A Wiley Company. #12;A Numerical Method for Computing Time gain or loss), these coherent structures generally exist as continuous families, parameterized
Mean-field analysis of quantum phase transitions in a periodic optical superlattice
Dhar, Arya; Singh, Manpreet; Pai, Ramesh V.; Das, B. P.
2011-09-15
We analyze the various phases exhibited by a system of ultracold bosons in a periodic optical superlattice using the mean-field decoupling approximation. We investigate for a wide range of commensurate and incommensurate densities. We find the gapless superfluid phase, the gapped Mott insulator phase, and gapped insulator phases with distinct density wave orders.
B 2004 Wiley Periodicals, Inc. The Opportunity of Stem Cell Bioengineering
Zandstra, Peter W.
B 2004 Wiley Periodicals, Inc. EDITORIAL The Opportunity of Stem Cell Bioengineering Stem cells Bioengineering''--an endeavor focused on quantita- tive description of stem cell fate processes and the use. For the bioengineering com- munity, stem cells represent an ideal focus (and natural evolution) for our mammalian cell
Shechter, Guy; Resar, Jon R.; McVeigh, Elliot R. [Lab of Cardiac Energetics, NHLBI, NIH Building 10, Room B1D-412, msc-1061, Bethesda, Maryland 20892-1061 (United States); Division of Cardiology, Department of Medicine, Johns Hopkins University, 600 North Wolfe Street, Blalock 524B, Baltimore, Maryland 21287 (United States); Lab of Cardiac Energetics, NHLBI, NIH Building 10, Room B1D-412, msc-1061, Bethesda, Maryland 20892-1061 (United States)
2005-01-01
Magnetic resonance (MR) and computed tomography coronary imaging is susceptible to artifacts caused by motion of the heart. The presence of rest periods during the cardiac and respiratory cycles suggests that images free of motion artifacts could be acquired. In this paper, we studied the rest period (RP) duration of the coronary arteries during a cardiac contraction and a tidal respiratory cycle. We also studied whether three MR motion correction methods could be used to increase the respiratory RP duration. Free breathing x-ray coronary angiograms were acquired in ten patients. The three-dimensional (3D) structure of the coronary arteries was reconstructed from a biplane acquisition using stereo reconstruction methods. The 3D motion of the arterial model was then recovered using an automatic motion tracking algorithm. The motion field was then decomposed into separate cardiac and respiratory components using a cardiac respiratory parametric model. For the proximal-to-middle segments of the right coronary artery (RCA), a cardiac RP (<1 mm 3D displacement) of 76{+-}34 ms was measured at end systole (ES), and 65{+-}42 ms in mid-diastole (MD). The cardiac RP was 80{+-}25 ms at ES and 112{+-}42 ms at MD for the proximal 5 cm of the left coronary tree. At end expiration, the respiratory RP (in percent of the respiratory period) was 26{+-}8% for the RCA and 27{+-}17% for the left coronary tree. Left coronary respiratory RP (<0.5 mm 3D displacement) increased with translation (32% of the respiratory period), rigid body (51%), and affine (79%) motion correction. The RCA respiratory RP using translational (27%) and rigid body (33%) motion correction were not statistically different from each other. Measurements of the cardiac and respiratory rest periods will improve our understanding of the temporal and spatial resolution constraints for coronary imaging.
PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637-752
Godfrey, L. E. H.; Ekers, R.; Lovell, J. E. J.; Burke-Spolaor, S.; Bicknell, G. V.; Jauncey, D. L.; Birkinshaw, M.; Worrall, D. M.; Schwartz, D. A.; Marshall, H. L.; Gelbord, J.; Perlman, E. S.; Georganopoulos, M.
2012-10-20
We present 18 GHz Australia Telescope Compact Array imaging of the megaparsec-scale quasar jet PKS 0637-752 with angular resolution {approx}0.''58. We draw attention to a spectacular train of quasi-periodic knots along the inner 11'' of the jet, with average separation {approx}1.1 arcsec (7.6 kpc projected). We consider two classes of model to explain the periodic knots: those that involve a static pattern through which the jet plasma travels (e.g., stationary shocks) and those that involve modulation of the jet engine. Interpreting the knots as re-confinement shocks implies the jet kinetic power Q{sub jet} {approx} 10{sup 46} erg s{sup -1}, but the constant knot separation along the jet is not expected in a realistic external density profile. For models involving modulation of the jet engine, we find that the required modulation period is 2 Multiplication-Sign 10{sup 3} yr < {tau} < 3 Multiplication-Sign 10{sup 5} yr. The lower end of this range is applicable if the jet remains highly relativistic on kiloparsec scales, as implied by the IC/CMB model of jet X-ray emission. We suggest that the periodic jet structure in PKS 0637-752 may be analogous to the quasi-periodic jet modulation seen in the microquasar GRS 1915+105, believed to result from limit cycle behavior in an unstable accretion disk. If variations in the accretion rate are driven by a binary black hole, the predicted orbital radius is 0.7 pc {approx}< a {approx}< 30 pc, which corresponds to a maximum angular separation of {approx}0.1-5 mas.
Prototyping of the ILC Baseline Positron Target
Gronberg, J; Brooksby, C; Piggott, T; Abbott, R; Javedani, J; Cook, E
2012-02-29
The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototyping effort on this system.
Prototyping of the ILC Baseline Positron Target
Gronberg, Jeff; Piggott, Tom; Abbott, Ryan; Javedani, Jay; Cook, Ed
2012-01-01
The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototyping effort on this system.
Tracking multiple generation and suppression of secondary electrons on periodic triangular surface
Li, S.; Wang, J. G.; Zhu, M.; Peng, J. C.; Xie, J. L.; Wu, X. L.; Guo, L. T.; Chang, C.; Xiong, Z. F.; Department of Engineering Physics, Tsinghua University, Beijing 10084
2013-12-15
To research the dynamic course of multipactor suppression on the periodically patterned surface, tens of electron collision processes are tracked by numerical calculation. The influences of microwave frequency, amplitude of RF electric field, slope angle, the local field enhancement, and the tilted incident electric field on the multipactor suppression are studied by tracking multi-generation electrons' trajectories, hopping and flight time, collision energy, and secondary emission yield. Meanwhile, the dynamic processes of secondary electrons on the periodic surface are analyzed by particle-in-cell (PIC) simulation. The PIC results are consistent with the analytical results in which the electrons fly reciprocatingly between the slopes and impact on the slopes; the methods of increasing the slope angle, enlarging the RF field, and lowering the frequency in a certain range are helpful to enhance the multipactor suppression steadily and persistently.
Quasi-periodic events in crystal plasticity and the self-organized avalanche oscillator
Stefanos Papanikolaou; Dennis M. Dimiduk; Woosong Choi; James P. Sethna; Michael D. Uchic; Chris F. Woodward; Stefano Zapperi
2013-05-11
When external stresses in a system - physical, social or virtual - are relieved through impulsive events, it is natural to focus on the attributes of these avalanches. However, during the quiescent periods in between, stresses may be relieved through competing processes, such as slowly flowing water between earthquakes or thermally activated dislocation flow between plastic bursts. Such unassuming, smooth responses can have dramatic effects on the avalanche properties. Here we report a thorough experimental investigation of slowly compressed Ni microcrystals, covering three orders of magnitude in nominal strain rate, that exhibits unconventional quasi-periodic avalanche bursts and higher critical exponents as the strain rate is decreased. Our analytic and computational study naturally extends dislocation avalanche modeling to incorporate dislocation relaxations and reveals the emergence of the self-organized avalanche oscillator, a novel critical state exhibiting oscillatory approaches toward a depinning critical point. We demonstrate that the predictions of our theory are faithfully exhibited in our experiments.
Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2014-06-09
Laser-induced periodic surface structures (LIPSS) are formed near 110?nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vector influencing LIPSS formation on bulk surfaces.
Geometrical investigation of the kinetic evolution of the magnetic field in a periodic flux rope
Restante, A. L.; Lapenta, G. [Afdeling Plasma-astrofysica, Departement Wiskunde, KULeuven, University of Leuven, Leuven (Belgium)] [Afdeling Plasma-astrofysica, Departement Wiskunde, KULeuven, University of Leuven, Leuven (Belgium); Markidis, S. [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)] [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden); Intrator, T. [Los Alamos National Laboratory, M.S. E526, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, M.S. E526, Los Alamos, New Mexico 87545 (United States)
2013-08-15
Flux ropes are bundles of magnetic field wrapped around an axis. Many laboratory, space, and astrophysics processes can be represented using this idealized concept. Here, a massively parallel 3D kinetic simulation of a periodic flux rope undergoing the kink instability is studied. The focus is on the topology of the magnetic field and its geometric structures. The analysis considers various techniques such as Poincaré maps and the quasi-separatrix layer (QSL). These are used to highlight regions with expansion or compression and changes in the connectivity of magnetic field lines and consequently to outline regions where heating and current may be generated due to magnetic reconnection. The present study is, to our knowledge, the first QSL analysis of a fully kinetic 3D particle in cell simulation and focuses the existing QSL method of analysis to periodic systems.
Optimized shooting method for finding periodic orbits of nonlinear dynamical systems
W. Dednam; A. E. Botha
2014-08-14
An alternative numerical method is developed to find stable and unstable periodic orbits of nonlinear dynamical systems. The method exploits the high-efficiency of the Levenberg-Marquardt algorithm for medium-sized problems and has the additional advantage of being relatively simple to implement. It is also applicable to both autonomous and non-autonomous systems. As an example of its use, it is employed to find periodic orbits in the R\\"ossler system, a coupled R\\"ossler system, as well as an eight-dimensional model of a flexible rotor-bearing; problems which have been treated previously via two related methods. The results agree with the previous methods and are seen to be more accurate in some cases. A simple implementation of the method, written in the Python programming language, is provided as an Appendix.
Homogenization of a thin plate reinforced with periodic families of rigid rods
Nazarov, Sergei A; Sweers, Guido H; Slutskij, Andrey S
2011-08-31
The asymptotics of the solution to the elastic bending problem for a thin plate reinforced with several periodic families of closely spaced but disjoint rods are constructed and justified, the result of homogenization being substantially different from the case when the rods are welded together into a single periodic mesh. The material in the rods is assumed to be appreciably more rigid than that in the plate. An averaged fourth-order differential operator is obtained from summing the nonelliptic operators generated by each of the families of the rods. This operator is shown to be elliptic if and only if the rods from at least two families are nonparallel. As a simplified example, the paper examines a similar stationary heat conduction problem. Bibliography: 24 titles.
Quasi-Periodic Formaldehyde Maser Flares in the Massive Protostellar Object IRAS18566+0408
Araya, E D; Goss, W M; Kurtz, S; Richards, A M S; Linz, H; Olmi, L; Sewilo, M
2010-01-01
We report results of an extensive observational campaign of the 6 cm formaldehyde maser in the young massive stellar object IRAS18566+0408 (G37.55+0.20) conducted from 2002 to 2009. Using Arecibo, VLA, and GBT, we discovered quasi-periodic formaldehyde flares (P ~ 237 days). Based on Arecibo observations, we also discovered correlated variability between formaldehyde (H2CO) and methanol (CH3OH) masers. The H2CO and CH3OH masers are not spatially coincident, as demonstrated by different line velocities and high angular resolution MERLIN observations. The flares could be caused by variations in the infrared radiation field, possibly modulated by periodic accretion onto a young binary system.
Entangled three-particle states in magnetic field: Periodic correlations and density matrices
Amitabha Chakrabarti; Anirban Chakraborti
2010-04-28
We present a novel study of the time evolutions of entangled states of three spin-1/2 particles in the presence of a constant external magnetic field, which causes the individual spins to precess and leads to remarkable periodicities in the correlations and density matrices. The emerging patterns of periodicity are studied explicitly for different entangled states and in detail for a particular initial configuration of the velocities. Contributions to precession of anomalous magnetic moments are analysed and general results are also obtained. We then introduce an electric field orthogonal to the magnetic field, linking to the preceding case via a suitable Lorentz transformation, and obtain the corresponding Wigner rotations of the spin states. Finally, we point out for the first time that the entangled states corresponding to well-known ones in the study of 3-particle entanglements, may be classified systematically using a particular coupling of three angular momenta.
Long Term Simulations Of Astrophysical Jets; Energy Structure and Quasi-Periodic Ejection
Ahmed Ibrahim; Kazunari Shibata
2007-04-23
We have performed self-consistent 2.5-dimensional nonsteady MHD numerical simulations of jet formation as long as possible, including the dynamics of accretion disks. Although the previous nonsteady MHD simulations for astrophysical jets revealed that the characteristics of nonsteady jets are similar to those of steady jets, the calculation time of these simulations is very short compared with the time scale of observed jets. Thus we have investigated long term evolutions of mass accretion rate, mass outflow rate, jet velocity, and various energy flux. We found that the ejection of jet is quasi-periodic. The period of the ejection is related to the time needed for the initial magnetic filed to be twisted to generate toroidal filed. We compare our results with both the steady state theory and previous 2.5-dimensional nonsteady MHD simulations.
Analytical Chemistry Division. Annual progress report for period ending December 31, 1981
Lyon, W.S. (ed.)
1982-04-01
The functions of the Analytical Chemistry Division fall into three general categories: (1) analytical research, development, and implementation; (2) programmatic research, development and utilization; (3) technical support. The Division is organized into five major sections each of which may carry out any type of work falling into the thre categories mentioned above. Chapters 1 through 5 of this report highlight progress within the five sections which are: analytical methodology; mass and emission spectrometry; analytical technical support; bio/organic analysis section; and nuclear and radiochemical analysis. A short summary introduces each chapter to indicate work scope. Information about quality assurance and safety programs is presented in Chapter 6, along with a tabulation of analyses rendered. Chapter 7 covers supplementary activities. Chapter 8 is on presentation of research results (publications, articles reviewed or referred for periodicals). Approximately 56 articles, 31 proceedings publications and 33 reports have been published, and 119 oral presentations given during this reporting period.
Glann Seaborg's Contributions to Heavy Element Science and the Periodic Table
Hobart, David E.
2012-08-17
In celebrating the centennial anniversary of the birth of Glenn T. Seaborg it is fitting that we recount and pay tribute to his legacy. Many know of the scientific accomplishments of this man who became a legend and anyone who has attended his lectures can attest to how informative, educational, and entertaining he was. He had a beguiling and whimsical sense of humor and used this to drive home his points and share his passion and quest for discovery. The periodic table is a fundamental cornerstone of science and remains a central unifying principal. Seaborg was the architect of the actinide series of elements and their proper placement in the periodic table and co-discoverer of ten transuranium elements - one of which bears his name, element 106, seaborgium. The work and achievements of this Nobel laureate have touched the lives of many and his legacy will continue for generations to come.
Dissociation of nitrogen in a pulse-periodic dielectric barrier discharge at atmospheric pressure
Popov, N. A., E-mail: npopov@mics.msu.su [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)
2013-05-15
Nitrogen molecule dissociation in a pulse-periodic atmospheric-pressure dielectric barrier discharge is numerically analyzed. It is shown that the quenching rate of predissociation states at atmospheric pressure is relatively low and the production of nitrogen atoms in this case can be adequately described using the cross section for electron-impact dissociation of N{sub 2} molecules taken from the paper by P.C. Cosby [J. Chem. Phys. 98, 9544 (1993)].
Nonlinear periodic waves solutions of the nonlinear self-dual network equations
Laptev, Denis V. Bogdan, Mikhail M.
2014-04-15
The new classes of periodic solutions of nonlinear self-dual network equations describing the breather and soliton lattices, expressed in terms of the Jacobi elliptic functions have been obtained. The dependences of the frequencies on energy have been found. Numerical simulations of soliton lattice demonstrate their stability in the ideal lattice and the breather lattice instability in the dissipative lattice. However, the lifetime of such structures in the dissipative lattice can be extended through the application of ac driving terms.
Pouya Partovi-Azar; T. D. Kühne
2015-04-17
We extend the method of Silvestrelli [P. L. Silvestrelli, J. Chem. Phys. 139, 054106 (2013)] to approximate long-range van der Waals interactions at the density functional theory level based on maximally localized Wannier functions combined with the quantum harmonic oscillator model, to periodic systems. Applying this scheme to study London dispersion forces between graphene and water layers, we demonstrate that collective many-body effects beyond simple additive pair-wise interactions are essential to accurately describe van der Waals forces.
Sub-GeV Electron and Positron Channeling in Straight, Bent and Periodically Bent Silicon Crystals
Sushko, G B; Greiner, Walter; Solov'yov, A V
2013-01-01
Preliminary results of numerical simulations of electron and positron channeling and emission spectra are reported for straight, uniformly bent and periodically bent silicon crystal. The projectile trajectories are computed using the newly developed module [1] of the MBN Explorer package [2,3]. The electron and positron channeling along Si(110) and Si(111) crystallographic planes are studied for the projectile energies 195--855 MeV.
Engineering Physics and Mathematics Division progress report for period ending December 31, 1992
Ward, R.C.
1993-05-01
In this report, our research is described through abstracts of journal articles, technical reports, and presentations organized into sections following the five major operating units in the division: Mathematical Sciences, Intelligent Systems, Nuclear Data and Measurement Analysis, Nuclear Analysis and Shielding, and the Engineering Physics Information Centers. Each section begins with an introduction highlighting honors, awards, and significant research accomplishments in that unit during the reporting period.
Dental analysis of Classic period population variability in the Maya area
Scherer, Andrew Kenneth
2005-02-17
is still debated. Some researchers believe Teotihuacan exhibited direct control of select Maya sites (Adams 1986; Coggins 1983). Others see the relationship between Teotihuacan and the Maya as one of mutual trade and respect (Demarest and Foias 1993... by distance model. I collected dental nonmetric and metric traits on 977 skeletons, from 18 Classic period sites, representing seven different archaeological zones. I corrected the data for intraobserver error. For the dental nonmetric data, I developed...
Partovi-Azar, Pouya
2015-01-01
We extend the method of Silvestrelli [P. L. Silvestrelli, J. Chem. Phys. 139, 054106 (2013)] to approximate long-range van der Waals interactions at the density functional theory level based on maximally localized Wannier functions combined with the quantum harmonic oscillator model, to periodic systems. Applying this scheme to study London dispersion forces between graphene and water layers, we demonstrate that collective many-body effects beyond simple additive pair-wise interactions are essential to accurately describe van der Waals forces.
Schmuck, Markus
2012-01-01
We formally derive an effective catalyst layer model comprising the reduction of oxygen for periodically distributed pore geometries. By assumption, the pores are completely filled with water and the surrounding walls consist of catalyst particles which are attached to an electron conducting microstructure. The macroscopic transport equations are established by a multi-scale approach, based on microscopic phenomena at the pore level, and serve as a first step toward future optimization of catalyst layer designs.
Markus Schmuck; Peter Berg
2012-04-30
We formally derive an effective catalyst layer model comprising the reduction of oxygen for periodically distributed pore geometries. By assumption, the pores are completely filled with water and the surrounding walls consist of catalyst particles which are attached to an electron conducting microstructure. The macroscopic transport equations are established by a multi-scale approach, based on microscopic phenomena at the pore level, and serve as a first step toward future optimization of catalyst layer designs.
Piezoelectrics by Design: A Route through Short-period Perovskite Superlattices
Das, Hena; Saha-Dasgupta, T
2010-01-01
Using first-principles density functional theory, we study piezoelectricity in short-period superlattices made with combination of ferroelectric and paraelectric components and exhibiting polar discontinuities. We show that piezoelectric response of such a superlattice can be tuned both in terms of sign and magnitude with a choice of its components. As these superlattices with nonswitchable polarization do not undergo ferroelectric transitions, we predict them to exhibit a robust piezoelectric response with weaker temperature dependence compared to their bulk counterparts.
Solid State Division progress report for period ending March 31, 1997
Green, P.H.; Hinton, L.W.
1997-12-01
This report covers research progress in the Solid State Division from April 1, 1995, through March 31, 1997. During this period, the division conducted a broad, interdisciplinary materials research program in support of Department of Energy science and technology missions. The report includes brief summaries of research activities in condensed matter theory, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. An addendum includes listings of division publications and professional activities.
P. A. Patsis; E. M. Xilouris
2005-12-09
The vertical profiles of disc galaxies are built by the material trapped around stable periodic orbits, which form their "skeletons". According to this, the knowledge of the stability of the main families of periodic orbits in appropriate 3D models, can predict possible morphologies for edge-on disc galaxies. In a pilot survey we compare the orbital structures which lead to the appearance of "peanuts" and "X"-like features with the edge-on profiles of three disc galaxies (IC 2531, NGC 4013 and UGC 2048). The subtraction from the images of a model representing the axisymmetric component of the galaxies reveals the contribution of the non-axisymmetric terms. We find a direct correspondence between the orbital profiles of 3D bars in models and the observed main morphological features of the residuals. We also apply a simple unsharp masking technique in order to study the sharpest features of the images. Our basic conclusion is that the morphology of the boxy "bulges" of these galaxies can be explained by considering disc material trapped around stable 3D periodic orbits. In most models these building-blocks periodic orbits are bifurcated from the planar central family of a non-axisymmetric component, usually a bar, at low order vertical resonances. In such a case the boxy "bulges" are parts of bars seen edge-on. For the three galaxies we study the families associated with the "peanut" or "X"-shape morphology are most probably bifurcations at the vertical 2/1 or 4/1 resonance.
Stevens, Fred J. (Naperville, IL)
1992-01-01
A novel method of electric field flow fractionation for separating solute molecules from a carrier solution is disclosed. The method of the invention utilizes an electric field that is periodically reversed in polarity, in a time-dependent, wave-like manner. The parameters of the waveform, including amplitude, frequency and wave shape may be varied to optimize separation of solute species. The waveform may further include discontinuities to enhance separation.
Quantum Energy Expectation in Periodic Time-Dependent hamiltonians via Green Functions
Cesar R. de Oliveira; Mariza S. Simsen
2009-07-31
Let $U_F$ be the Floquet operator of a time periodic hamiltonian $H(t)$. For each positive and discrete observable $A$ (which we call a {\\em probe energy}), we derive a formula for the Laplace time average of its expectation value up to time $T$ in terms of its eigenvalues and Green functions at the circle of radius $e^{1/T}$. Some simple applications are provided which support its usefulness.
Solid State Division progress report for period ending September 30, 1984
Green, P.H.; Watson, D.M.
1985-03-01
During the reporting period, relatively minor changes have occurred in the research areas of interest to the Division. Nearly all the research of the Division can be classified broadly as mission-oriented basic research. Topics covered include: theoretical solid state physics; surface and near-surface properties of solids; defects in solids; transport properties of solids; neutron scattering; and preparation and characterization of research materials. (GHT)
MAXI J1659-152: the shortest orbital period black-hole binary
Kuulkers, E; van der Horst, A J; Belloni, T; Chenevez, J; Ibarra, A; Munoz-Darias, T; Bazzano, A; Bel, M Cadolle; De Cesare, G; Trigo, M Diaz; Jourdain, E; Lubinski, P; Natalucci, L; Ness, J -U; Parmar, A; Pollock, A M T; Rodriguez, J; Roques, J -P; Sanchez-Fernandez, C; Ubertini, P; Winkler, C
2011-01-01
Following the detection of a bright new X-ray source, MAXI J1659-152, a series of observations was triggered with almost all currently flying high-energy missions. We report here on XMM-Newton, INTEGRAL and RXTE observations during the early phase of the X-ray outburst of this transient black-hole candidate. We confirm the dipping nature in the X-ray light curves. We find that the dips recur on a period of 2.4139+/-0.0005 hrs, and interpret this as the orbital period of the system. It is thus the shortest period black-hole X-ray binary known to date. Using the various observables, we derive the properties of the source. The inclination of the accretion disk with respect to the line of sight is estimated to be 60-75 degrees. The companion star to the black hole is possibly a M5 dwarf star, with a mass and radius of about 0.15 M_sun and 0.23 R_sun, respectively. The system is rather compact (orbital separation is about 1.35 R_sun) and is located at a distance of roughly 7 kpc. In quiescence, MAXI J1659-152 is e...
The continuous period search method and its application to the young solar analogue HD 116956
Lehtinen, J; Hackman, T; Henry, P Kajatkari G W
2010-01-01
Aims: We formulate an improved time series analysis method for the analysis of photometry of active stars. This new Continuous Period Search (CPS) method is applied to 12 years of V band photometry of the young solar analogue HD 116956 (NQ UMa). Methods: The new method is developed from the previous Three Stage Period Analysis (TSPA) method. Our improvements are the use of a sliding window in choosing the modelled datasets, a criterion applied to select the best model for each dataset and the computation of the time scale of change of the light curve. We test the performance of CPS with simulated and real data. Results: The CPS has a much improved time resolution which allows us to better investigate fast evolution of stellar light curves. We can also separate between the cases when the data is best described by periodic (i.e. rotational modulation of brightness) and aperiodic (e.g. constant brightness) models. We find, however, that the performance of the CPS has certain limitations. It does not determine th...
Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds
Mikhail M. Labushev
2013-03-20
The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. Beta-packet of oxides and hydroxides minerals includes 88 known minerals and five chemical compounds - N2O5, CO2, CO, SO3 and SO2. Two minerals of the packet have not been determined yet. Besides, beta-packet of minerals with sulfur, selenium or arsenic is composed, with one mineral not defined yet. The results of the calculations can be used for further development of the Periodic Table of Chemical Elements and Chemical Compounds and their properties investigation.
Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds
Labushev, Mikhail M
2013-01-01
The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. Beta-packet of oxides and hydroxides minerals includes 88 known minerals and five chemical compounds - N2O5, CO2, CO, SO3 and SO2. Two minerals of the packet have not been determined yet. Besides, beta-packet of minerals with sulfur, selenium or arsenic is composed, with one mineral not defined yet. The results of the calculations can be used for further development of the Periodic Table of Chemical Elements and Chemical Compounds and their properties investigation.
THE FREQUENCY OF LOW-MASS EXOPLANETS. III. TOWARD {eta}{sub +} AT SHORT PERIODS
Wittenmyer, Robert A.; Tinney, C. G.; Bailey, J.; Horner, J.; Butler, R. P.; O'Toole, Simon J.; Jones, H. R. A.; Carter, B. D.
2011-09-01
Determining the occurrence rate of 'super-Earth' planets (m sin i < 10 M{sub +}) is a critically important step on the path toward determining the frequency of Earth-like planets ({eta}{sub +}), and hence the uniqueness of our solar system. Current radial-velocity surveys, achieving precisions of 1 m s{sup -1}, are now able to detect super-Earths and provide meaningful estimates of their occurrence rate. We present an analysis of 67 solar-type stars from the Anglo-Australian Planet Search specifically targeted for very high precision observations. When corrected for incompleteness, we find that the planet occurrence rate increases sharply with decreasing planetary mass. Our results are consistent with those from other surveys: in periods shorter than 50 days, we find that 3.0% of stars host a giant (msin i > 100 M{sub +}) planet, and that 17.4% of stars host a planet with msin i < 10 M{sub +}. The preponderance of low-mass planets in short-period orbits is in conflict with formation simulations in which the majority of super-Earths reside at larger orbital distances. This work gives a hint as to the size of {eta}{sub +}, but to make meaningful predictions on the frequency of terrestrial planets in longer, potentially habitable orbits, low-mass terrestrial planet searches at periods of 100-200 days must be made an urgent priority for ground-based Doppler planet searches in the years ahead.
Vector Riemann-Hilbert problem with almost periodic and meromorphic coefficients and applications
Yuri A. Antipov
2015-04-21
The vector Riemann-Hilbert problem is analyzed when the entries of its matrix coefficient are meromorphic and almost periodic functions. Three cases for the meromorphic functions, when they have (i) a finite number of poles and zeros (rational functions), (ii) periodic poles and zeros, and (iii) an infinite number of non periodic zeros and poles, are considered. The first case is illustrated by the heat equation for a composite rod with a finite number of discontinuities and a system of convolution equations; both problems are solved explicitly. In the second case, a Wiener-Hopf factorization is found in terms of the hypergeometric functions, and the exact solution of a mixed boundary value problem for the Laplace equation in wedge is derived. In the last case, the Riemann-Hilbert problem reduces to an infinite system of linear algebraic equations with the exponential rate of convergence. As an example, the Neumann boundary value problem for the Helmholtz equation in a strip with a slit is analyzed.
Periodicities in the X-ray emission from the solar corona
Chowdhury, Partha; Jain, Rajmal; Awasthi, Arun K. E-mail: parthares@gmail.com E-mail: awasthi@prl.res.in
2013-11-20
We have studied the time series of full disk integrated soft and hard X-ray emission from the solar corona during 2004 January to 2008 December, covering the entire descending phase of solar cycle 23 from a global point of view. We employ the daily X-ray index derived from 1 s cadence X-ray observations from the Si and CZT detectors of the 'Solar X-ray Spectrometer' mission in seven different energy bands ranging between 6 and 56 keV. X-ray data in the energy bands 6-7, 7-10, 10-20, and 4-25 keV from the Si detector are considered, while 10-20, 20-30, and 30-56 keV high energy observations are taken from the CZT detector. The daily time series is subjected to power spectrum analysis after appropriate correction for noise. The Lomb-Scargle periodogram technique has shown prominent periods of ?13.5 days, ?27 days, and a near-Rieger period of ?181 days and ?1.24 yr in all energy bands. In addition to this, other periods like ?31, ?48, ?57, ?76, ?96, ?130, ?227, and ?303 days are also detected in different energy bands. We discuss our results in light of previous observations and existing numerical models.
QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS
Huppenkothen, Daniela; Watts, Anna L.; Uttley, Phil; Van der Horst, Alexander J.; Van der Klis, Michiel; Kouveliotou, Chryssa; Goegues, Ersin; Granot, Jonathan; Vaughan, Simon; Finger, Mark H.
2013-05-01
The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and QPOs at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ruling out false positives. We illustrate our Bayesian method by applying it to a sample of 27 bursts from the magnetar SGR J0501+4516 observed by the Fermi Gamma-ray Burst Monitor, and we find no evidence for the presence of QPOs in any of the bursts in the unbinned spectra, but do find a candidate detection in the binned spectra of one burst. However, whether this signal is due to a genuine quasi-periodic process, or can be attributed to unmodeled effects in the noise is at this point a matter of interpretation.
A search for periodicities from a ULX in the LINER galaxy NGC 4736
Avdan, H; Akyuz, A; Balman, S
2014-01-01
We report our findings on a new quasi-periodic oscillation (QPO) and a long period from the ultraluminous X-ray source (ULX) X-2 in nearby galaxy NGC 4736 based on the Chandra and XMM-Newton archival data. To examine the timing properties, power density spectra of the source have been obtained using Fast Fourier Transform. Also the spectral parameters of the source have been calculated by obtaining and fitting the energy spectra. Power density spectrum of this source reveals a QPO peak at $0.73_{-0.14}^{+0.16}$ mHz with an fractional rms variability of 16% using the Chandra data (in the year 2000-lower state of the source). The XMM-Newton data analysis indicates a peak at $0.53_{-0.35}^{+0.09}$ mHz with a fractional rms variation of 5% (in the year 2006-higher state of the source). These recovered QPOs overlap within errors and may be the same oscillation. In addition, we detect a long periodicity or a QPO in the Chandra data of about $(5.2\\pm2.0)\\times10^{-5}$ Hz ($\\sim$ 5.4 hrs) over 3 $\\sigma$ confidence l...
Edge effects in propagation of terahertz radiation in subwavelength periodic structures
Gelmont, B. Parthasarathy, R.; Globus, T.
2008-08-15
Improving detection sensitivity of biological molecules with low absorption characteristics in the terahertz gap still remains an important issue in terahertz vibrational resonance spectroscopy. One possible way to increase coupling of incident terahertz radiation to molecules is to exploit local enhancement of electromagnetic field in periodic slot arrays. In this work, we show that periodic arrays of rectangular slots with subwavelength widths provide for local electromagnetic field enhancements due to edge effects in our low frequency range of interest, 10-25 cm{sup -1}. Periodic structures of Au doped Si and InSb were studied. The half power enhancement width is {approx}500 nm or less around the slot, edges in all cases, thereby possibly bringing terahertz sensing to the nanoscale. InSb is confirmed to offer the highest results with local power enhancements on the order of 1100 at frequency 14 cm{sup -1}. InSb and Si have large skin depths in our frequency range of interest and so the analysis of their structures was done through the Fourier expansion method of field diffracted from gratings. Surface impedance boundary conditions were employed to model the Au structure. The applications possibly include development of novel biosensors, and monitoring biophysical processes such as DNA denaturation.
Classification of Floquet Statistical Distribution for Time-Periodic Open Systems
Dong E. Liu
2015-04-07
How to understand the order of Floquet stationary states in the presence of external bath coupling and their statistical mechanics is challenging; the answers are important for preparations and control of those Floquet states. Here, we propose a scheme to classify the statistical distribution of Floquet states for time-periodic systems which couple to an external heat bath. If an effective Hamiltonian and a system-bath coupling operator, which are all time-independent, can be simultaneously obtained via a time-periodic unitary transformation, the statistical mechanics of the Floquet states is equivalent to the equilibrium statistical mechanics of the effective Hamiltonian. In the large driving frequency cases, we also show that the conditions of this theorem can be weakened to: the time-period part in the system Hamiltonian commutes with the system-bath coupling operator. A Floquet-Markov approach is applied to numerically compute the Floquet state occupation distribution of a bosonic chain, and the results agree with the theoretical predictions.