Type Ia Supernovae and the Hubble Constant
D. Branch
1998-01-08
The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant ($H_0$). SNe Ia are well suited for measuring $H_0$. A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than $\\sigma_{obs}(M_B) \\simeq \\sigma_{obs}(M_V) \\simeq 0.3$ mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways --- empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at $M_B \\simeq M_V \\simeq -19.4$ or -19.5. Various ways that have been used to match Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed out in the Hubble flow have given values of $H_0$ distributed throughout the range 54 to 67 km/s Mpc$^{-1}$. Astronomers who want a consensus value of $H_0$ from SNe Ia with conservative errors could, for now, use $60 \\pm 10$ km/s Mpc^{-1}$.
The Hubble Constant from Type Ia Supernovae in Early-Type Galaxies
Tom Richtler; Georg Drenkhahn
1999-09-07
Type Ia supernovae (SNe) are the best standard candles available today in spite of an appreciable intrinsic variation of their luminosities at maximum phase, and of probably non-uniform progenitors. For an unbiased use of type Ia SNe as distance indicators it is important to know accurately how the decline rate and colour at maximum phase correlate with the peak brightness. In order to calibrate the Hubble diagram of type Ia SNe, i.e. to derive the Hubble constant, one needs to determine the absolute brightness of nearby type Ia SNe. Globular cluster systems of early type Ia host galaxies provide suitable distance indicators. We discuss how Ia SNe can be calibrated and explain the method of Globular Cluster Luminosity Functions (GCLFs). At present, the distance to the Fornax galaxy cluster is most important for deriving the Hubble constant. Our present data indicate a Hubble constant of H_0=72+-4 km/s/Mpc. As an appendix, we summarise what is known about absolute magnitudes of Ia's in late-type galaxies.
Hardy–Sobolev Type Inequalities with Sharp Constants in Carnot ...
2010-06-22
We also obtain a sharp inequality of Hardy–Sobolev type. Keywords Hardy ... an inequality of Hardy type such as Eq. 1.1 be valid in the setting of Carnot groups.
Goobar, A.
2008-01-01
at z = 1. uncertainty for supernovae at z = 1. mR Adding theMass Density .Q Using Type Ia Supernovae A. Goobar and S.Density Q Using Type Ia Supernovae Ariel Goobar l and Saul
Staying Informed | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
like the Automobile Association of America and GasBuddy.com for information about gasoline and diesel fuel prices. Stay tuned to local media reports. Seek out information...
A Multilevel Model of RN Workgroup Intent to Stay
Miller, Peggy A.
2007-12-07
An understanding of how determinants of RN intent to stay on the unit vary by unit type is essential for developing the targeted retention strategies that are an important component of efforts to address the evolving nursing shortage. Relationships...
Design optimization of cable-stayed bridges
Bessas, Georgios
2006-01-01
The goal of this thesis is to achieve a basic understanding of cable-stayed systems. Issues to be treated are the diachronic evolution of cable-stayed bridges, including the advantages, the limitations and the basic design ...
Staying Informed | Department of Energy
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 APPENDIX E LIST OF APPLICABLEStatutory Authority for an SPR Drawdown Statutory AuthorityStaying
Timely PTS Applications Critical to Staying Navy
Timely PTS Applications Critical to Staying Navy Navy Personnel Command (NPC) is reminding commands and Sailors that submitting Perform to Serve (PTS) applications is the key to being able to stay Navy/10 explains how PTS is used to shape the Navy, and includes all business rules concerning. Commands must
Staying the Course | 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: Alternative FuelsofProgram: Report15 Meeting State Energy Advisory BoardStateFailures |Staying the
TEOS 02 La Selva soil and root dynamics: What happens in soil, stays in soil Team Members
Soatto, Stefano
TEOS 02 La Selva soil and root dynamics: What happens in soil, stays in soil Team Members · Michael. This includes clay soils, high precipitation, and relatively constant warm temperatures. Another importance flux network, and a large database on ecological dynamics. Approach Soil AMR units and sensor networks
Stay Above Water with an Efficient Swimming Pool | Department...
Office of Environmental Management (EM)
Above Water with an Efficient Swimming Pool Stay Above Water with an Efficient Swimming Pool August 10, 2009 - 10:38am Addthis Allison Casey Senior Communicator, NREL All eyes were...
Win-stay lose-shift strategy in formation changes in football
Tamura, Kohei
2015-01-01
Managerial decision making is likely to be a dominant determinant of performance of teams in team sports. Here we use Japanese and German football data to investigate correlates between temporal patterns of formation changes across matches and match results. We found that individual teams and managers both showed win-stay lose-shift behavior, a type of reinforcement learning. In other words, they tended to stick to the current formation after a win and switch to a different formation after a loss. In addition, formation changes did not affect the results of succeeding matches in most cases. The results indicate that a swift implementation of a new formation in the win-stay lose-shift manner may not be a successful managerial rule of thumb.
Stay Warm in Your Apartment | Department of Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And StatisticsProgram Manager Directory Small BusinessAgreements |Emissions Targets |StatesStay
Cosmology with Varying Constants
C. J. A. P. Martins
2000-08-18
I motivate and discuss some recent work on theories with varying constants, and consider some possible observational consequences and tests. Particular emphasis is given to models which can (almost) exactly mimic the predictions of standard inflationary models.
Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2007
Dr. Michael G. Finn
2010-01-04
Study of the stay rate in the United States of foreign nationals receiving their S/E doctorates from U.S. universities. This study has estimated stay rates in 2007 for persons receiving a doctorate one, two, five, and ten years previously. The two-year stay rate (for 2005 graduates) recovered from the decline experienced earlier in the decade. The five-year stay rate (for 2002 graduates) is lower; the ten-year stay rate (for 1997 graduates) reached a new high.
Chinese supercomputer stays No. 1, Titan at ORNL still No. 2...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Chinese supercomputer stays No. 1, Titan at ORNL still No. 2 November 18, 2014 For the fourth consecutive time, Tianhe-2, a supercomputer developed by China's National University...
R. L. Collins
2006-01-10
Hubble plots of the distance of stellar objects vs. recession velocity normally assume the red shift is wholly Doppler and ignore any gravitational contribution. This is unwarranted: gravity and Doppler velocity red shifts are found to be separable and contribute about equally. A recent data set, to Z=1.2, by Riess (1), was analyzed. Upon plotting distance vs. Doppler velocity, the slope of the Hubble plot increases. The Hubble plot is also curved, upwards, and this can be understood in terms of the relativistic metric changes of the space through which the light travels. On fitting the data to a simple model of a big bang of constant density, this finds the total mass of the big bang is M=21.1x10^52 kg. When present actual distance is plotted vs. Doppler velocity, the plot is linear and agrees with Hubble's concept, without acceleration. Time since the big bang is longer than the 14 billion years that had been thought, 23.5 billion years. The Hubble constant hence shrinks from Ho=71 to Ho=41.6. This is an independent affirmation of a recent CMB finding of a low Ho=35.
Unitaxial constant velocity microactuator
McIntyre, Timothy J. (Knoxville, TN)
1994-01-01
A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-manometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment.
Unitaxial constant velocity microactuator
McIntyre, T.J.
1994-06-07
A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment is disclosed. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-nanometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment. 10 figs.
Samuels, Fallon M. (Fallon Michele)
2007-01-01
A history and theory of cable-stayed bridges in the context of a cultural discourse on civil construction projects' value, this thesis studies the significance of cable-stayed bridge designs to 'value engineering' objectives ...
How Do You Stay Cool and Comfortable in Hot Weather? | Department...
- 5:25pm Addthis As you may have read on the blog over the past few weeks, the Stay Cool, Save Money site offers no-cost and low-cost tips for saving energy during the warm summer...
Stay on marked paths to avoid poison ivy. Watch young children carefully around river and creeks.
Shyy, Wei
Caution · Stay on marked paths to avoid poison ivy. · Watch young children carefully around river or outdoor cooking are not permitted. Poison Ivy Hours · Trails and gardens open 8 am to dusk. · Conservatory
Non-Destructive Evaluation of Bridge Stay Cable and External Post-Tensioning Systems
McCoy, Katlyn Mae
2014-10-09
, sounding, ultrasonic tomography, infrared thermography, and ground penetrating radar are evaluated for their applicability to identify selected conditions in a mock-up specimen representative of both a stay cable system and an external PT system. A...
Winter Weather Preparedness Have a Plan -Make a Kit -Stay Informed
Oklahoma, University of
Winter Weather Preparedness Have a Plan - Make a Kit - Stay Informed during winter weather. Move livestock to sheltered areas with non-frozen drinking. If necessary insulate walls and attic. Caulk and weather-strip doors and windowsills
Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2005
Mike Finn
2008-02-01
This is the latest in a series of studies conducted for the National Science Foundation to estimate the proportion of foreign science / engineering doctorate recipients from U.S. universities who stayed in the United States after graduation. Sixty-six percent of those who graduated in 2003 were still in the United States in 2005, a 5 percent decline since the last report. But the five-year stay rate continues to climb, now at 68 percent.
QCD coupling constants and VDM
Erkol, G.; Ozpineci, A.; Zamiralov, V. S.
2012-10-23
QCD sum rules for coupling constants of vector mesons with baryons are constructed. The corresponding QCD sum rules for electric charges and magnetic moments are also derived and with the use of vector-meson-dominance model related to the coupling constants. The VDM role as the criterium of reciprocal validity of the sum rules is considered.
Constant Volume During Combustion | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Constant Volume During Combustion Constant Volume During Combustion This presentation covers constant volume during combustion and discusses how it can alter the kinematics of...
How fundamental are fundamental constants?
M. J. Duff
2014-12-17
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, alpha. For example, the Standard Model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers, scales... they use to measure them. Dimensional constants, on the other hand, such as h, c, G, e, k..., are merely human constructs whose number and values differ from one choice of units to the next. In this sense only dimensionless constants are "fundamental". Similarly, the possible time variation of dimensionless fundamental "constants" of nature is operationally well-defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might disagree depending on their apparatus. All these confusions disappear if one asks only unit-independent questions. We provide a selection of opposing opinions in the literature and respond accordingly.
How fundamental are fundamental constants?
Duff, M J
2014-01-01
I argue that the laws of physics should be independent of one's choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, alpha. For example, the Standard Model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers, scales... they use to measure them. Dimensional constants, on the other hand, such as h, c, G, e, k..., are merely human constructs whose number and values differ from one choice of units to the next. In this sense only dimensionless constants are "fundamental". Similarly, the possible time variation of dimensionless fundamental "constants" of nature is operationally well-defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might...
Hardy–Sobolev Type Inequalities with Sharp Constants in Carnot ...
2011-03-02
Jun 24, 2010 ... To introduce our main result consider a system X = {X1, ..., Xm} of C ... (personal communication), where a similar construction was carried in ...
The Effects of Quantum Entropy on the Bag Constant
Miller, D E; Miller, David E.; Tawfik, Abdel-Nasser
2003-01-01
The effects of quantum entropy on the bag constant are studied at low temperatures and small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag constant without the quantum entropy almost does not change with the temperature and the quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant.
Stay protected when connected Visit security.duke.edu for more information.
McShea, Daniel W.
Stay protected when connected Visit security.duke.edu for more information. Follow these guidelines Visit security.duke.edu for more information. Follow these tips for securing mobile devices: iOS 6/software/. Windows Mac Another free option: Microsoft Security Essentials: http://windows.microsoft.com/en- US/windows/products/security
Evaluating Risk of Terrorist Attack on a Cable Stayed Bridge: A Probabilistic Structural
Bhattacharya, Baidurya
Evaluating Risk of Terrorist Attack on a Cable Stayed Bridge: A Probabilistic Structural Analysis and administrators are able to evaluate risks to infrastructure in their jurisdiction in a rational manner. This will enable them to take optimal actions to manage these risks given budgetary constraints. This paper
March 2012 BEE CULTURE 29 unlucky spider struggling to stay in
Delaplane, Keith S.
to waste venom on us. Each time a spider discharges venom, it can take up to two weeks for the venomMarch 2012 BEE CULTURE 29 unlucky spider struggling to stay in her web, that can send shivers up of the details may be a bit fuzzy. It was 1998 when he spoke to our department. Built back in 1929, the Geor
DAMAGE IDENTIFICATION IN A BENCHMARK CABLE-STAYED BRIDGE USING THE INTERPOLATION METHOD
Boyer, Edmond
DAMAGE IDENTIFICATION IN A BENCHMARK CABLE-STAYED BRIDGE USING THE INTERPOLATION METHOD Marco mariagiuseppina.limongelli@polimi.it ABSTRACT In this paper the damage localization algorithm based on Operational Deformed Shapes (ODS) and known as Interpolation Damage Detection Method (IDDM), is applied
Staying Competitive in the 90's: How to Make Public Involvement Work for Your Energy Project
Loveless, K. W.
1993-01-01
with development plans and to stay competitive, they must have broad-based public support for their projects. Today few energy projects are stopped because they lack the technical capability to produce clean and affordable energy, but because they lack the public...
Do birds from one population group stay together through their migration
Keeling, Patrick
and crossed the Gulf of Mexico. In the spring migration northward (b), coastal birds followed a similar returnDo birds from one population group stay together through their migration to the tropics and back the geolocators showed where the birds had been through their migration. Coastal birds followed the western coast
FROM CONSTANT TO NON-DEGENERATELY VANISHING MAGNETIC FIELDS IN SUPERCONDUCTIVITY
the distribution of superconductivity in a type II superconductor submitted to a vari- able magnetic fieldFROM CONSTANT TO NON-DEGENERATELY VANISHING MAGNETIC FIELDS IN SUPERCONDUCTIVITY BERNARD HELFFER- tivity in a type II superconductor subjected to a constant magnetic field. The second function describes
Renormalization of Newton's constant and Particle Physics
X. Calmet
2010-02-02
We report on particle physics applications of the renormalization group equation of Newton's constant.
Brown, Matt
2013-01-01
type T y[O]. The operator IsIs is self-applicative, in thatargument t is any of Is[O] or IsIs, and otherwise behavesproof constant introduced by IsIs proves that the type of t
An Issue to the Cosmological Constant Problem
R. Triay
2005-04-07
According to general relativity, the present analysis shows on geometrical grounds that the cosmological constant problem is an artifact due to the unfounded link of this fundamental constant to vacuum energy density of quantum fluctuations.
PHYSICS & ASTRONOMY DATA CARD Physical Constants
Greenaway, Alan
's constant h 6.626 x 10-34 J s Ñ= h/2 1.055 x 10-34 J s Avogadro's constant NA 6.022 x 1023 mol-1 Boltzmann
Johnson, Eric N.
A DISPLAY CONCEPT FOR STAYING AHEAD OF THE AIRPLANE Eric N. Johnson, Lockheed Martin Aeronautical Systems, Marietta, Georgia David C. Hansen, Lockheed Martin Aeronautical Systems, Marietta, Georgia manner required for many aerospace applications. Considerably more data fusion, data prediction, alerting
Stay Active this Summer (and Save Energy, Money, and the Environment too!)
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 RankADVANCED MANUFACTURINGEnergyPlan | Department of Energy 1 DOE| Department of Energy Stay Active
Staying on Track for a Career in R&D|GE Global Researh
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 AdministrationRobust,Field-effect Photovoltaics -7541C.3X-rays3 Prepared by: Michael G. Finn ScienceStaying on
Stay Up To Date on Hurricane Sandy Recovery Efforts | Department of Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LIST OF APPLICABLEStatutory Authority for an SPR Drawdown Statutory Authority forStay
The Hubble Constant from the Fornax Cluster Distance
Tom Richtler; Georg Drenkhahn; Matias Gomez; Wilhelm Seggewiss
1999-05-17
Type Ia supernovae are the best cosmological standard candles available. The intrinsic scatter of their decline-rate- and colour-corrected peak brightnesses in the Hubble diagram is within observational error limits, corresponding to an uncertainty of only 3km/s/Mpc of the Hubble constant. Any additional uncertainty, resulting from peak-brightness calibration, must be kept small by measuring distances to nearby host galaxies most precisely. A number of different distance determinations of the Fornax cluster of galaxies agree well on a distance modulus of 31.35+-0.04mag (18.6+-0.3Mpc). This leads to accurate absolute magnitudes of the well-observed Fornax type Ia SNe SN1980N, SN1981D, and SN1992A and finally to a Hubble constant of H_0=72+-6km/s/Mpc.
Emergent cosmological constant from colliding electromagnetic waves
Halilsoy, M.; Mazharimousavi, S. Habib; Gurtug, O. E-mail: habib.mazhari@emu.edu.tr
2014-11-01
In this study we advocate the view that the cosmological constant is of electromagnetic (em) origin, which can be generated from the collision of em shock waves coupled with gravitational shock waves. The wave profiles that participate in the collision have different amplitudes. It is shown that, circular polarization with equal amplitude waves does not generate cosmological constant. We also prove that the generation of the cosmological constant is related to the linear polarization. The addition of cross polarization generates no cosmological constant. Depending on the value of the wave amplitudes, the generated cosmological constant can be positive or negative. We show additionally that, the collision of nonlinear em waves in a particular class of Born-Infeld theory also yields a cosmological constant.
Constant voltage electro-slag remelting control
Schlienger, M.E.
1996-10-22
A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an electrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable. 1 fig.
Constant voltage electro-slag remelting control
Schlienger, Max E. (Albuquerque, NM)
1996-01-01
A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.
Berryman, J.G.; Nakagawa, S.
2009-11-20
Poroelastic analysis has traditionally focused on the relationship between dry or drained constants which are assumed known and the saturated or undrained constants which are assumed unknown. However, there are many applications in this field of study for which the main measurements can only be made on the saturated/undrained system, and then it is uncertain what the eects of the uids were on the system, since the drained constants remain a mystery. The work presented here shows how to deduce drained constants from undrained constants for anisotropic systems having symmetries ranging from isotropic to orthotropic. Laboratory ultrasound data are then inverted for the drained constants in three granular packings: one of glass beads, and two others for distinct types of more or less angular sand grain packings. Experiments were performed under uniaxial stress, which resulted in hexagonal (transversely isotropic) symmetry of the poroelastic response. One important conclusion from the general analysis is that the drained constants are uniquely related to the undrained constants, assuming that porosity, grain bulk modulus, and pore uid bulk modulus are already known. Since the resulting system of equations for all the drained constants is linear, measurement error in undrained constants also propagates linearly into the computed drained constants.
Vacuum Fluctuations and the Cosmological Constant
Shi Qi
2006-04-29
The hypothesis is proposed that under the approximation that the quantum equations of motion reduce to the classical ones, the quantum vacuum also reduces to the classical vacuum--the empty space. The vacuum energy of QED is studied under this hypothesis. A possible solution to the cosmological constant problem is provided and a kind of parameterization of the cosmological "constant" is derived.
Chemistry 365: Force Constant Calculations David Ronis
Ronis, David M.
cost energy, and hence, there will no force in thy y or z directions (thereby resulting in 4 zero eigenChemistry 365: Force Constant Calculations © David Ronis McGill University Here is an example of a force constant matrix calculation. We will consider a diatomic molecule, where the two atoms interact
Fundamental Physical Constants: Looking from Different Angles
Savely G. Karshenboim
2005-07-28
We consider fundamental physical constants which are among a few of the most important pieces of information we have learned about Nature after its intensive centuries-long studies. We discuss their multifunctional role in modern physics including problems related to the art of measurement, natural and practical units, origin of the constants, their possible calculability and variability etc.
Bubble Universes With Different Gravitational Constants
Yu-ichi Takamizu; Kei-ichi Maeda
2015-04-21
We argue a scenario motivated by the context of string landscape, where our universe is produced by a new vacuum bubble embedded in an old bubble and these bubble universes have not only different cosmological constants, but also their own different gravitational constants. We study these effects on the primordial curvature perturbations. In order to construct a model of varying gravitational constants, we use the Jordan-Brans-Dicke (JBD) theory where different expectation values of scalar fields produce difference of constants. In this system, we investigate the nucleation of bubble universe and dynamics of the wall separating two spacetimes. In particular, the primordial curvature perturbation on superhorizon scales can be affected by the wall trajectory as the boundary effect. We show the effect of gravitational constant in the exterior bubble universe can provide a peak like a bump feature at a large scale in a modulation of power spectrum.
Bubble Universes With Different Gravitational Constants
Takamizu, Yu-ichi
2015-01-01
We argue a scenario motivated by the context of string landscape, where our universe is produced by a new vacuum bubble embedded in an old bubble and these bubble universes have not only different cosmological constants, but also their own different gravitational constants. We study these effects on the primordial curvature perturbations. In order to construct a model of varying gravitational constants, we use the Jordan-Brans-Dicke (JBD) theory where different expectation values of scalar fields produce difference of constants. In this system, we investigate the nucleation of bubble universe and dynamics of the wall separating two spacetimes. In particular, the primordial curvature perturbation on superhorizon scales can be affected by the wall trajectory as the boundary effect. We show the effect of gravitational constant in the exterior bubble universe can provide a peak like a bump feature at a large scale in a modulation of power spectrum.
Hydrogen, Deuterium and Tritium in Palladium: An Elastic Constants Study
Bach, H.T.; Schwarz, R.B.; Tuggle, D.G.
2005-07-15
We have used resonant ultrasound spectroscopy to measure the three independent elastic constants of Pd-H, Pd-D, and Pd-T single crystal at 300K as a function of hydrogen, deuterium, and tritium concentration, respectively. The addition of interstitial H (D, or T) atoms, located at (0,1/2,0) in the fcc Pd lattice, affects all three elastic constants C', C{sub 44}, and B. In the mixed ({alpha}+{beta}) phase, and with increasing H isotope, the shear modulus C' shows an abnormal softening whereas C{sub 44} and B do not. This is explained in terms of Zener-type an elastic relaxations affecting the shape of the hydride phases in the coherent({alpha}+{beta}) two-phase mixture In the single {beta}-phase, C' shows a strong isotope dependence whereas C{sub 44} and B show none. This behavior is explained in terms of differences in the excitation of optical phonons. In Pd-T, {sup 3}He is produced by the radioactive decay of tritium. We have measured in situ the swelling and the change in the elastic constants in Pd-T as a function of aging time. Aging ({sup 3}He formation) affects all three elastic constants. These measurements are being used to understand the early stages of {sup 3}H-{sup 3}He cluster formation in aged Pd-T crystal.
Hydrogen, deuterium and tritium in palladium: An eleastic constants study
Bach, H. T.; Schwarz, R. B.; Tuggle, D. G.
2004-01-01
We have used resonant ultrasound spectroscopy to measure the three independent elastic constants of Pd-H, Pd-D, and Pd-T single crystal at 300K as a junction of hydrogen, deuterium, and tritium concentration, respectively. The addition of interstitial H (D, or T) atoms, located at (0, 1/2, 0) in the fcc Pd lattice, affects all three elastic constants C, C{sub 44}, and B. In the mixed (a+{beta}) phase, and with increasing H isotope, the shear modulus C' shows an abnormal softening whereas C{sub 44} and B do not. This is explained in terms of Zener-type anelastic relaxations affecting the shape of the hydride phases in the coherent ({alpha}+{beta}) two-phase mixture In the single {beta}-phase, C' shows a strong isotope dependence whereas C{sub 44} and B show none. This behavior is explained in terms of differences in the excitation of optical phonons. In Pd-T, {sup 3}He is produced by the radioactive decay of tritium. We have measured in situ the swelling and the change in the elastic constants in Pd-T as a function of aging time. Aging ({sup 3}He formation) affects all three elastic constants. These measurements are being used to understand the early stages of {sup 3}H-{sup 3}He clusterformation in aged Pd-T crystal.
Heun equation, Teukolsky equation, and type-D metrics
D. Batic; H. Schmid
2007-01-15
Starting with the whole class of type-D vacuum backgrounds with cosmological constant we show that the separated Teukolsky equation for zero rest-mass fields with spin $s=\\pm 2$ (gravitational waves), $s=\\pm 1$ (electromagnetic waves) and $s=\\pm 1/2$ (neutrinos) is an Heun equation in disguise.
The Meaning Of The Fine Structure Constant
R. L. Oldershaw
2009-02-21
A possible explanation is offered for the longstanding mystery surrounding the meaning of the fine structure constant. The reasoning is based on a discrete self-similar cosmological paradigm that has shown promise in explaining the general scaling properties of nature's global hierarchy. The discrete scale invariance of the paradigm implies that "strong gravity" governs gravitational interactions within atomic scale systems. Given the revised gravitational coupling constant and Planck mass, one can demonstrate that the fine structure constant is the ratio of the strengths of the unit electromagnetic interaction and the unit gravitational interaction within atomic scale systems. [Abridged
A Nuclear Data Approach for the Hubble Constant Measurements
Pritychenko, B
2015-01-01
An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP) codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.00(770) (km/sec)/Mpc. This recommended value is based on the last 25 years of experimental research and includes contributions from different types of measurements. The present result implies (14.6$\\pm$1.7)$\\times$10$^{9}$ years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.
Lovley, Derek
Planetsave Like this post? Subscribe to our RSS feed and stay up to date. Navy Develops Battery that Runs on Mud (http://planetsave.com/blog/2010/04/20/navy-develops-battery-that-runs-on- mud/) (http by Joshua S Hill Published on April 20th, 2010 in Energy & Fuel 1 Comment 5/4/2010 Navy Develops Battery
Kunkle, Tom
IN AN EMERGENCY, CALL PUBLIC SAFETY AT 843.953.5611 Stay informed. Be prepared. Visit emergency instructions from emergency personnel · Do not use elevators. · Take personal belongings (ID, keys, purses authorized to do so by emergency personnel. FIRES · Activate the nearest fire alarm pull station. · Call
McCalley, James D.
2010-01-01
of a cable-stayed bridge using smart sensor technology: deployment and evaluation Shinae Jang1*, Hongki Jo1 monitoring; wireless smart sensor network; cable-stayed bridge; deploy- ment; evaluation. 1. IntroductionSmart Structures and Systems, Vol. 6, No. 5-6 (2010) 439-459 439 Structural health monitoring
Will the Next Generation Stay or Go? Communications That Support Family Business Unity Steve Lytle Director, The Agnew Company & Principal, Clearpath Services Wednesday, April 15, 2015 Hayden's Lakefront the future of the family business can often mean the difference between whether successors stay or go
Gravitational Interactions and Fine-Structure Constant
U. D. Jentschura; J. H. Noble; I. Nandori
2015-02-01
Electromagnetic and gravitational central-field problems are studied with relativistic quantum mechanics on curved space-time backgrounds. Corrections to the transition current are identified. Analogies of the gravitational and electromagnetic spectra suggest the definition of a gravitational fine-structure constant. The electromagnetic and gravitational coupling constants enter the Einstein-Hilbert-Maxwell Lagrangian. We postulate that the variational principle holds with regard to a global dilation transformation of the space-time coordinates. The variation suggests is consistent with a functional relationship of the form alpha_QED being proportional to alpha_G^(1/2), where alpha_QED is the electrodynamic fine-structure constant, and alpha_G its gravitational analogue.
Our Universe from the cosmological constant
Barrau, Aurélien; Linsefors, Linda E-mail: linda.linsefors@lpsc.in2p3.fr
2014-12-01
The issue of the origin of the Universe and of its contents is addressed in the framework of bouncing cosmologies, as described for example by loop quantum gravity. If the current acceleration is due to a true cosmological constant, this constant is naturally conserved through the bounce and the Universe should also be in a (contracting) de Sitter phase in the remote past. We investigate here the possibility that the de Sitter temperature in the contracting branch fills the Universe with radiation that causes the bounce and the subsequent inflation and reheating. We also consider the possibility that this gives rise to a cyclic model of the Universe and suggest some possible tests.
The Vacuum and the Cosmological Constant Problem
Gerald E. Marsh
2008-06-20
It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the vacuum polarization tensor--must be eliminated either explicitly or by some form of regularization followed by renormalization. It has recently been shown that lack of gauge invariance is a result of the way the vacuum is defined, and redefining the vacuum so that the theory is gauge invariant may also offer a solution to the cosmological constant problem.
Electromagnetic corrections to pseudoscalar decay constants
Benjamin Glaessle; Gunnar S. Bali
2011-11-16
The effects of electromagnetic interactions on pseudoscalar decay constants are investigated. Using a compact QED and QCD action we are able to resolve differences of about 0.1 MeV. We obtain the preliminary results f_pi^0-f_pi^+/- =0.09(3) MeV and f_D^0-f_D^+/- =0.79(11) MeV for light and charmed pseudoscalar decay constants on a N_f=2 nonperturbatively improved Sheikholeslami-Wohlert ensemble.
Microfabricated microengine with constant rotation rate
Romero, Louis A. (Albuquerque, NM); Dickey, Fred M. (Albuquerque, NM)
1999-01-01
A microengine uses two synchronized linear actuators as a power source and converts oscillatory motion from the actuators into constant rotational motion via direct linkage connection to an output gear or wheel. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque at a constant rotation to a micromechanism. The output gear can have gear teeth on its outer perimeter for directly contacting a micromechanism requiring mechanical power. The gear is retained by a retaining means which allows said gear to rotate freely. The microengine is microfabricated of polysilicon on one wafer using surface micromachining batch fabrication.
Environmental Dependence of Masses and Coupling Constants
Keith A. Olive; Maxim Pospelov
2008-01-04
We construct a class of scalar field models coupled to matter that lead to the dependence of masses and coupling constants on the ambient matter density. Such models predict a deviation of couplings measured on the Earth from values determined in low-density astrophysical environments, but do not necessarily require the evolution of coupling constants with the redshift in the recent cosmological past. Additional laboratory and astrophysical tests of \\Delta \\alpha and \\Delta(m_p/m_e) as functions of the ambient matter density are warranted.
Matyushov, Dmitry
Thermodynamics and dynamics of a monoatomic glass former. Constant pressure and constant volume-pressure simulations of the thermodynamic and dynamic properties of the low-temperature liquid and crystalline phases the thermodynamics of the configurational manifold as an ensemble of excitations, each carrying an excitation entropy
Vacuum Fluctuations Cannot Mimic a Cosmological Constant
Robert D. Klauber
2007-11-05
When the vacuum fluctuation pressure is calculated directly from fundamental principles of quantum field theory, in the same manner as vacuum fluctuation energy density is commonly calculated, one finds it is not equal to the negative of the vacuum fluctuation energy density. Thus, vacuum fluctuations cannot manifest as a cosmological constant of any order.
Soil Moisture Constants and Physical Properties
, Kauai, and Oahu. These soils represent 10 great soil groups commonly found in the State of HawaiiSoil Moisture Constants and Physical Properties of Selected Soils in Hawaii Teruo Yamamoto U S is a geologist with the Pacific Southwest Sta- tion's watershed management research project in Honolulu, Hawaii
Variable energy constant current accelerator structure
Anderson, O.A.
1988-07-13
A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90/degree/ intervals with opposing electrodes maintained at the same potential. 12 figs., 3 tabs.
Cosmological Constant Problems and Renormalization Group
Ilya L. Shapiro; Joan Sola
2007-01-05
The Cosmological Constant Problem emerges when Quantum Field Theory is applied to the gravitational theory, due to the enormous magnitude of the induced energy of the vacuum. The unique known solution of this problem involves an extremely precise fine-tuning of the vacuum counterpart. We review a few of the existing approaches to this problem based on the account of the quantum (loop) effects and pay special attention to the ones involving the renormalization group.
Can Compactifications Solve the Cosmological Constant Problem?
Hertzberg, Mark P
2015-01-01
Recently, there have been claims in the literature that the cosmological constant problem can be dynamically solved by specific compactifications of gravity from higher-dimensional toy models. These models have the novel feature that in the four-dimensional theory, the cosmological constant $\\Lambda$ is much smaller than the Planck density and in fact accumulates at $\\Lambda=0$. Here we show that while these are very interesting models, they do not properly address the real cosmological constant problem. As we explain, the real problem is not simply to obtain $\\Lambda$ that is small in Planck units in a toy model, but to explain why $\\Lambda$ is much smaller than other mass scales (and combinations of scales) in the theory. Instead, in these toy models, all other particle mass scales have been either removed or sent to zero, thus ignoring the real problem. To this end, we provide a general argument that the included moduli masses are generically of order Hubble, so sending them to zero trivially sends the cos...
Which Fundamental Constants for CMB and BAO?
Rich, James
2015-01-01
We study the Cosmic Microwave Background using the three-scale framework of Hu et al. to derive the dependence of the CMB temperature anisotropy spectrum on the fundamental constants. We show that, as expected, the observed spectrum depends only on \\emph{dimensionless} combinations of the constants, and we emphasize the points that make this generally true for cosmological observations. Our analysis suggests that the CMB spectrum shape is mostly determined by $\\alpha^2m_e/m_p$ and the proton-CDM-particle mass ratio, $m_p/\\mchi$, with a sub-dominant dependence on $(G\\mchi m_e/\\hbar c)\\alpha^\\beta$ with $\\beta\\sim -7$. The distance to the last-scattering surface depends on $Gm_p\\mchi/\\hbar c$, so published CMB observational limits on time variations of the constants, besides making assumptions about the form of the dark-energy, implicitly assume the time-independence of this quantity. On the other hand, low-redshift $H_0$, BAO and large-scale structure data can be combined with the \\emph{shape} of the CMB spect...
Computing the dielectric constant of liquid water at constant dielectric displacement
Zhang, Chao
2015-01-01
The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement D. The method to constrain the electric displacement is the finite temperature classical variant of the constant-D method developed by Stengel, Spaldin and Vanderbilt (Nat. Phys. 2009, 5: 304). There is also a modification of this scheme imposing fixed values of the macroscopic field E. The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at D = 0 and E = 0 and two from the variation of polarization with finite D and E. It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies however, with constant D calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polar...
Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)] [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)
2014-01-21
Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.
On the D-anity of the ag variety in type B 2 Henning Haahr Andersen
Andersen, Henning Haahr
On the D-aÃ?nity of the ag variety in type B 2 #3; Henning Haahr Andersen Matematisk Institut of Mathematics, Osaka City University for a very pleasant stay there during the month of November 1999. 1 Ã? p-#12
On the local variation of the Hubble constant
Odderskov, Io; Hannestad, Steen [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Haugbølle, Troels, E-mail: isho07@phys.au.dk, E-mail: sth@phys.au.dk, E-mail: troels.haugboelle@snm.ku.dk [Centre for Star and Planet Formation, Natural History Museum of Denmark and Niels Bohr Institute University of Copenhagen, DK-1350 Copenhagen (Denmark)
2014-10-01
We have carefully studied how local measurements of the Hubble constant, H{sub 0}, can be influenced by a variety of different parameters related to survey depth, size, and fraction of the sky observed, as well as observer position in space. Our study is based on N-body simulations of structure in the standard ?CDM model and our conclusion is that the expected variance in measurements of H{sub 0} is far too small to explain the current discrepancy between the low value of H{sub 0} inferred from measurements of the cosmic microwave background (CMB) by the Planck collaboration and the value measured directly in the local universe by use of Type Ia supernovae. This conclusion is very robust and does not change with different assumptions about effective sky coverage and depth of the survey or observer position in space.
Self-gravitating scalar breathers with negative cosmological constant
Gyula Fodor; Péter Forgács; Philippe Grandclément
2015-07-10
Breather-type (time-periodic and spatially localized) solutions with spherical symmetry are investigated in a massless scalar field theory coupled to Einstein's gravity with cosmological constant in $d$ spatial dimensions imposing anti de Sitter (AdS) asymptotics on space-time. Using a code constructed with the Kadath library that enables the use of spectral methods, the phase space of breather solutions is explored in detail for $d=3$ and $d=4$. It is found that there are discrete families of solutions indexed by an integer and by their frequency. Using a time evolution code these AdS breathers are found to be stable for up to a critical central density, in analogy to boson stars. Using an analytical perturbative expansion small amplitude breathers are worked out for arbitrary dimensions $d$.
Seismic pulse propagation with constant Q and stable probability distributions
Francesco Mainardi; Massimo Tomirotti
2010-08-07
The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type) in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with index of stability determined by the order of the fractional time derivative in the evolution equation.
From constant to non-degenerately vanishing magnetic fields in superconductivity
Bernard Helffer; Ayman Kachmar
2015-03-30
We explore the relationship between two reference functions arising in the analysis of the Ginzburg-Landau functional. The first function describes the distribution of superconductivity in a type II superconductor subjected to a constant magnetic field. The second function describes the distribution of superconductivity in a type II superconductor submitted to a variable magnetic field that vanishes non-degenerately along a smooth curve.
Transmission eigenvalues for operators with constant coefficients
Michael Hitrik; Katsiaryna Krupchyk; Petri Ola; Lassi Päivärinta
2010-04-28
In this paper we study the interior transmission problem and transmission eigenvalues for multiplicative perturbations of linear partial differential operator of order $\\ge 2$ with constant real coefficients. Under suitable growth conditions on the symbol of the operator and the perturbation, we show the discreteness of the set of transmission eigenvalues and derive sufficient conditions on the existence of transmission eigenvalues. We apply these techniques to the case of the biharmonic operator and the Dirac system. In the hypoelliptic case we present a connection to scattering theory.
Stability of adhesion clusters under constant force
T. Erdmann; U. S. Schwarz
2004-01-27
We solve the stochastic equations for a cluster of parallel bonds with shared constant loading, rebinding and the completely dissociated state as an absorbing boundary. In the small force regime, cluster lifetime grows only logarithmically with bond number for weak rebinding, but exponentially for strong rebinding. Therefore rebinding is essential to ensure physiological lifetimes. The number of bonds decays exponentially with time for most cases, but in the intermediate force regime, a small increase in loading can lead to much faster decay. This effect might be used by cell-matrix adhesions to induce signaling events through cytoskeletal loading.
Constant-mesh, multiple-shaft transmission
Rea, J.E.; Mills, D.D.; Sewell, J.S.
1992-04-21
This patent describes a multiple-shaft, constant-mesh transmission adapted to establish selectively a reverse torque delivery path and a forward drive torque delivery path and having a torque input means including a torque input shaft, a mainshaft aligned with the input shaft, a countershaft geared to the input shaft in spaced, parallel relationship with respect to the mainshaft, a torque output shaft joined to the mainshaft; multiple mainshaft gear elements journalled on the main airshaft, multiple cluster gear elements carried by the countershaft in meshing engagement with the mainshaft gear elements, one of the cluster gear elements being rotatably journalled on the countershaft; a reverse idle gear, a reverse gear journalled on the countershaft, the reverse idler gear being in constant mesh with the reverse gear and one of the mainshaft gear elements; first clutch means for connecting selectively the reverse gear and the countershaft; second synchronizer clutch means for connecting selectively the one of the mainshaft gear elements to the mainshaft; and third synchronizer clutch means for selectively connecting another of the mainshaft gear elements to the mainshaft; the first clutch means being a double-acting clutch with a first common axially movable clutch element adapted upon movement in one axial direction to drivably connected the reverse gear to the countershaft and adapted upon movement in the opposite axial direction to connect the one cluster gear element to the countershaft.
Gravitational collapse and the cosmological constant
Deshingkar, S. S.; Jhingan, S.; Chamorro, A.; Joshi, P. S.
2001-06-15
We consider here the effects of a nonvanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that, depending on the nature of the initial data from which the collapse evolves, and for a positive value of the cosmological constant, we can have a globally regular evolution where a bounce develops within the cloud. We characterize precisely the initial data causing such a bounce in terms of the initial density and velocity profiles for the collapsing cloud. In the cases otherwise, the result of collapse is either the formation of a black hole or a naked singularity resulting as the end state of collapse. We also show here that a positive cosmological term can cover a part of the singularity spectrum which is visible in the corresponding dust collapse models for the same initial data.
CMB constraints on the fine structure constant
Kazuhide Ichikawa; Toru Kanzaki; Masahiro Kawasaki
2006-05-25
We study constraints on time variation of the fine structure constant alpha from cosmic microwave background (CMB) taking into account simultaneous change in alpha and the electron mass m_e which might be implied in unification theories. We obtain the constraints -0.097 < Delta alpha/alpha < 0.034 at 95% C.L. using WMAP data only, and -0.042 < Delta alpha/alpha < 0.026 combining with the constraint on the Hubble parameter by the HST Hubble Key Project. These are improved by 15% compared with constraints assuming only alpha varies. We discuss other relations between variations in alpha and m_e but we do not find evidence for varying alpha.
Constant field gradient planar coupled cavity structure
Kang, Y.W.; Kustom, R.L.
1999-07-27
A cavity structure is disclosed having at least two opposing planar housing members spaced apart to accommodate the passage of a particle beam through the structure between the members. Each of the housing members have a plurality of serially aligned hollows defined therein, and also passages, formed in the members, which interconnect serially adjacent hollows to provide communication between the hollows. The opposing planar housing members are spaced and aligned such that the hollows in one member cooperate with corresponding hollows in the other member to form a plurality of resonant cavities aligned along the particle beam within the cavity structure. To facilitate the obtaining of a constant field gradient within the cavity structure, the passages are configured so as to be incrementally narrower in the direction of travel of the particle beam. In addition, the spacing distance between the opposing housing members is configured to be incrementally smaller in the direction of travel of the beam. 16 figs.
Dimensionless constants, cosmology and other dark matters
Max Tegmark; Anthony Aguirre; Martin J Rees; Frank Wilczek
2006-01-11
We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin. Axion cosmology provides an instructive example, in which these two kinds of arguments must both be taken into account, and work well together. If a Peccei-Quinn phase transition occurred before or during inflation, then the axion dark matter density will vary from place to place with a probability distribution. By calculating the net dark matter halo formation rate as a function of all four relevant cosmological parameters and assessing other constraints, we find that this probability distribution, computed at stable solar systems, is arguably peaked near the observed dark matter density. If cosmologically relevant WIMP dark matter is discovered, then one naturally expects comparable densities of WIMPs and axions, making it important to follow up with precision measurements to determine whether WIMPs account for all of the dark matter or merely part of it.
Supply Fan Control for Constant Air Volume Air Handling Units
Cho, Y.; Wang, G.; Liu, M.
2007-01-01
Since terminal boxes do not have a modulation damper in constant volume (CV) air handling unit (AHU) systems, zone reheat coils have to be modulated to maintain the space temperature with constant supply airflow. This conventional control sequence...
The Hubble constant from $^{56}$Co-powered Nebular Candles
Pilar Ruiz-Lapuente
1996-04-10
Type Ia supernovae (SNe Ia), produced by the thermonuclear explosion of white dwarf (WD) stars, are used here to derive extragalactic distances and an estimate of the Hubble constant from their emission signatures at late phases ({\\it Nebular SNe Ia Method}, NSM). The method, first developed in Ruiz--Lapuente \\& Lucy (1992), makes use here of an improved modeling of the forbidden line emission at late phases. Hydrodynamic models of the explosion of WDs of different masses, both sub--Chandrasekhar and Chandrasekhar, provide the basis for comparison with the observations. It is shown that it is possible to probe the overall density structure of the ejecta and the mass of the exploding WD by the effect that the electron density profile has in shaping the forbidden line emission of the iron ions, and that a robust diagnostic of the mass of the exploding WD can be obtained. Cosmic distance scale can thus be related to basic diagnostics of excitation of iron lines. Once the most adequate model is selected, comparison of the predicted line emission at these phases with the observed spectra gives an internal estimate of both the reddening and the distance to the SNe Ia. The results presented here favor denser models than those corresponding to sub--Chandrasekhar explosions. From a sample of seven SNe Ia in Leo, Virgo, Fornax and beyond, a value of the Hubble constant $H_{0} = 68 \\ \\pm 6\\ (stat) \\pm 7\\ (syst)\\ km\\ s^{-1}\\ Mpc^{-1}$ is derived. The depth of the Virgo cluster is found to be large, ranging from 13 to 23 Mpc at least. If NGC 4526 traces well the core of the Virgo Cluster, then the latter is located at $16\\pm 2 \\ Mpc$. The galaxy NGC 3267 in Leo appears to be located at 9.8 $\\pm$ 1.5 Mpc.
The variation of the fine structure constant: testing the dipole model with thermonuclear supernovae
Kraiselburd, Lucila; Negrelli, Carolina; Berro, Enrique García
2014-01-01
The large-number hypothesis conjectures that fundamental constants may vary. Accordingly, the spacetime variation of fundamental constants has been an active subject of research for decades. Recently, using data obtained with large telescopes a phenomenological model in which the fine structure constant might vary spatially has been proposed. We test whether this hypothetical spatial variation of {\\alpha}, which follows a dipole law, is compatible with the data of distant thermonuclear supernovae. Unlike previous works, in our calculations we consider not only the variation of the luminosity distance when a varying {\\alpha} is adopted, but we also take into account the variation of the peak luminosity of Type Ia supernovae resulting from a variation of {\\alpha}. This is done using an empirical relation for the peak bolometric magnitude of thermonuclear supernovae that correctly reproduces the results of detailed numerical simulations. We find that there is no significant difference between the several phenome...
Cosmic explosions, life in the Universe and the Cosmological Constant
Piran, Tsvi; Cuesta, Antonio J; Simpson, Fergus; Verde, Licia
2015-01-01
Galactic Gamma-Ray Bursts (GRBs) are copious sources of gamma-rays that can pose a threat to complex life. Using recent determinations of their rate and the probability of GRBs causing massive extinction, we explore what type of universes are most likely to harbour advanced forms of life. For this purpose we use cosmological N-body simulations to determine at what time and for what value of the cosmological constant ($\\Lambda$) the chances of life being unaffected by cosmic explosions are maximised. We find that $\\Lambda-$dominated universes favour the survival of life against GRBs. Within a $\\Lambda$CDM cosmology, the parameters that govern the likelihood of life survival to GRBs are dictated by the value of $\\Lambda$ and the age of the Universe. We find that we seem to live in a favorable point in this parameter phase space which minimises the exposure to cosmic explosions, yet maximises the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.
Hacker, Randi; Tsutsui, William
2007-03-14
Sox spent a hundred mil to acquire pitcher Daisuke Matsuzaka; they probably weren't even aware that he is a Type O and that they make the best bankers, politicians and... you guessed it... professional baseball players. #ceas #hacker #japan #tsutsuien...
Going and Coming: Why U.S.-Educated Turkish PhD Holders Stay in the U.S. or Return to Turkey?
ESEN, EYYUP ESEN
2014-12-31
Abstract This qualitative study explores the underlying reasons of the decisions of U.S. educated Turkish professors to stay in the United States or return to Turkey. To collect data, interviews were conducted with a total of 20 U.S. educated...
Artemov, Sergei N.
If you are on official New York State or federal government business and staying in a hotel Keep this completed Form ST-129, Exemption Certificate, as evidence of exempt occupancy by New York a representative of the department, agency, or instrumentality of New York State, the United States government
Experimental determination of the effective strong coupling constant
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2005-09-15
We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Initial data sets with ends of cylindrical type: I. The Lichnerowicz equation
Piotr T. Chru?ciel; Rafe Mazzeo
2014-10-07
We construct large classes of vacuum general relativistic initial data sets, possibly with a cosmological constant Lambda, containing ends of cylindrical type.
Supersymmetric Kähler oscillator in a constant magnetic field
Stefano Bellucci; Armen Nersessian
2004-01-30
We propose the notion of the oscillator on K\\"ahler space and consider its supersymmetrization in the presence of a constant magnetic field.
Determination of the strong coupling constant ({alpha}{sub s...
Office of Scientific and Technical Information (OSTI)
Dissertation: Determination of the strong coupling constant (alphasub s) and a test of perturbative QCD using W + jets processes in the D0 detector Citation Details...
Flavor dependence of normalization constant for an infrared renormalon
Taekoon Lee
2015-02-09
An ansatz is proposed for the flavor dependence of the normalization constant for the first IR renormalon in heavy quark pole mass.
Type-0 second order nonlinear interaction in monolithic waveguides of
Type-0 second order nonlinear interaction in monolithic waveguides of isotropic semiconductors, Handbook of Optical Constants of Solids (Academic Prsee, Orlando, Florida, 1985). 5. M. Ravaro, M. Le D
Derived Types What Are Derived Types?
Collett Jr., Jeffrey L.
Derived Types #12;What Are Derived Types? As usual, a hybrid of two, unrelated concepts C++, Python orientation comes in #12;Simple Derived Types TYPE Wheel INTEGER :: spokes REAL :: diameter, width CHARACTER(LEN=15) :: material END TYPE Wheel That defines a derived type Wheel Using derived types needs a special
Derived Types What Are Derived Types?
Collett Jr., Jeffrey L.
Derived Types #12;What Are Derived Types? As usual, a hybrid of two, unrelated concepts C object orientation comes in This course will only describe the former. #12;Simple Derived Types TYPE That defines a derived type Wheel Using derived types needs a special syntax TYPE(Wheel) :: w1 #12;More
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS
Zucker, Robert S.
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS AND NEURONS WILFRID RALL From electrophysiological experiments. It depends upon the several time con- stants present in passive decay of membrane membrane time constant, Tm = RmCm, observed in the decay of a uniform membrane potential, there exist many
Applications of nonlocal constants of motion in Lagrangian Dynamics
Gianluca Gorni; Gaetano Zampieri
2015-01-29
We give a recipe to generate "nonlocal" constants of motion for ODE Lagrangian systems and we apply the method to find useful constants of motion for dissipative system, for the Lane-Emden equation, and for the Maxwell-Bloch system with RWA.
Equilibrium surface distributions for constant energy ensembles B. I. Henry
Henry, Bruce Ian
Equilibrium surface distributions for constant energy ensembles B. I. Henry Department of Applied distributions are seen [11,12]. In this paper we shall discuss how one calculates the constant energy energy en semble are discussed. An equilibrium surface density is introduced and used to calculate
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 RankADVANCEDInstallers/ContractorsPhotovoltaicsStateof Energy TwoEvent at the Pu Facility,Type IV COPV1
Evolving Lorentzian wormholes supported by phantom matter and cosmological constant
Mauricio Cataldo; Sergio del Campo; Paul Minning; Patricio Salgado
2008-12-23
In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made of phantom energy in the presence of a cosmological constant. We derive analytical evolving wormhole geometries by supposing that the radial tension of the phantom matter, which is negative to the radial pressure, and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. In this case the presence of a cosmological constant ensures accelerated expansion of the wormhole configurations. More specifically, for positive cosmological constant we have wormholes which expand forever and, for negative cosmological constant we have wormholes which expand to a maximum value and then recolapse. At spatial infinity the energy density and the pressures of the anisotropic phantom matter threading the wormholes vanish; thus these evolving wormholes are asymptotically vacuum $\\Lambda$-Friedmann models with either open or closed or flat topologies.
Energy Science and Technology Software Center (OSTI)
002851IBMPC00 STAYSL PNNL Suite http://radiochemscieng.pnnl.gov/research_areas/research_area_description.asp?id=283
Methodology for extracting local constants from petroleum cracking flows
Chang, Shen-Lin (Woodridge, IL); Lottes, Steven A. (Naperville, IL); Zhou, Chenn Q. (Munster, IN)
2000-01-01
A methodology provides for the extraction of local chemical kinetic model constants for use in a reacting flow computational fluid dynamics (CFD) computer code with chemical kinetic computations to optimize the operating conditions or design of the system, including retrofit design improvements to existing systems. The coupled CFD and kinetic computer code are used in combination with data obtained from a matrix of experimental tests to extract the kinetic constants. Local fluid dynamic effects are implicitly included in the extracted local kinetic constants for each particular application system to which the methodology is applied. The extracted local kinetic model constants work well over a fairly broad range of operating conditions for specific and complex reaction sets in specific and complex reactor systems. While disclosed in terms of use in a Fluid Catalytic Cracking (FCC) riser, the inventive methodology has application in virtually any reaction set to extract constants for any particular application and reaction set formulation. The methodology includes the step of: (1) selecting the test data sets for various conditions; (2) establishing the general trend of the parametric effect on the measured product yields; (3) calculating product yields for the selected test conditions using coupled computational fluid dynamics and chemical kinetics; (4) adjusting the local kinetic constants to match calculated product yields with experimental data; and (5) validating the determined set of local kinetic constants by comparing the calculated results with experimental data from additional test runs at different operating conditions.
EVALUATION OF CONSTANT CURRENT WELD CONTROL FOR PINCH WELDING
Korinko, P; STANLEY, S; HOWARD, H
2005-10-11
Modern weld controllers typically use current to control the weld process. SRS uses a legacy voltage control method. This task was undertaken to determine if the improvements in the weld control equipment could be implemented to provide improvements to the process control. The constant current mode of operation will reduce weld variability by about a factor of 4. The constant voltage welds were slightly hotter than the constant current welds of the same nominal current. The control mode did not appear to adversely affect the weld quality, but appropriate current ranges need to be established and a qualification methodology for both welding and shunt calibrations needs to be developed and documented.
Van't Hoff law for temperature dependent Langmuir constants in clathrate hydrate nanocavities
Lakhlifi, Azzedine
2015-01-01
This work gives a van't Hoff law expression of Langmuir constants of different species for determining their occupancy in the nanocavities of clathrate hydrates. The van't Hoff law's parameters are derived from a fit with Langmuir constants calculated using a pairwise site-site interaction potential to model the anisotropic potential environment in the cavities, as a function of temperature. The parameters can be used for calculating clathrates compositions. Results are given for nineteen gas species trapped in the small and large cavities of structure types I and II [1]. The accuracy of this approach is based on a comparison with available experimental data for ethane and cyclo- propane clathrate hydrates. The numerical method applied in this work, was recently validated from a comparison with the spherical cell method based on analytical considerations [1
Compactifications of F-Theory on Calabi-Yau Threefolds at Constant Coupli ng
Changhyun Ahn; Soonkeon Nam
1997-03-03
Generalizing the work of Sen, we analyze special points in the moduli space of the compactification of the F-theory on elliptically fibered Calabi-Yau threefolds where the coupling remains constant. These contain points where they can be realized as orbifolds of six torus $T^6$ by $Z_m \\times Z_n (m, n=2, 3, 4, 6)$. At various types of intersection points of singularities, we find that the enhancement of gauge symmetries arises from the intersection of two kinds of singularities. We also argue that when we take the Hirzebruch surface as a base for the Calabi- Yau threefold, the condition for constant coupling corresponds to the case where the point like instantons coalesce, giving rise to enhanced gauge group of $Sp(k)$.
Lovley, Derek
|Archives| Charts| Companies/Links| Conferences| How A Fuel Cell Works | Patents| | Types of Fuel Cells | The Basics | Fuel Cell News | Basics on Hydrogen | Search| *Stay Updated every week With a Free Subscription To "Inside The Industry"As Well as a Weekly Updated Patents Page Gulliver's fuel cell travels
Lovley, Derek
. These "metal-reducing" bacteria are ideal for fuel cells, said microbiologist Derek Lovley of the University|Archives| Charts| Companies/Links| Conferences| How A Fuel Cell Works | Patents| | Types of Fuel Cells | The Basics | Fuel Cell News | Basics on Hydrogen | Search| *Stay Updated every week With a Free
Calculation of the Dimer Equilibrium Constant of Heavy Water Saturated Vapor
L. A. Bulavin; S. V. Khrapatiy; V. N. Makhlaichuk
2015-03-13
Water is the most common substance on Earth.The discovery of heavy water and its further study have shown that the change of hydrogen for deuterium leads to the significant differences in their properties.The triple point temperature of heavy water is higher,at the same time the critical temperature is lower.Experimental values of the second virial coefficient of the EOS for the vapor of normal and heavy water differ at all temperatures.This fact can influence the values of the dimerization constant for the heavy water vapor.The equilibrium properties of the dimerization process are described with the methods of chemical thermodynamics.The chemical potentials for monomers (m) and dimers (d)are the functions of their concentrations.The interactions of monomer-dimer and dimer-dimer types are taken into account within the solution of equation for chemical potentials.The obtained expression for the dimerization constant contains the contributions of these types.The averaged potentials are modeled by the Sutherland potential.Theoretical values of the dimerization constant for the heavy water vapor at different temperatures are compared to those for normal water.We see the exceeding of the values for the heavy water at all temperatures.This fact is in good agreement with all experimental data that is available.The excess is related to the differences in the character of the heat excitations of the dimers of normal and heavy water,their rotational constants and energy of their vibrational excitations.Significant role is also played by the monomer-dimer and dimer-dimer interactions.
Statistical Inference for Models with Intractable Normalizing Constants
Jin, Ick Hoon
2011-06-27
In this dissertation, we have proposed two new algorithms for statistical inference for models with intractable normalizing constants: the Monte Carlo Metropolis-Hastings algorithm and the Bayesian Stochastic Approximation Monte Carlo algorithm...
Optimization Online - Optimality gap of constant-order policies ...
Linwei Xin
2014-09-07
Sep 7, 2014 ... Optimality gap of constant-order policies decays exponentially in the lead time for ... For the special case of exponentially distributed demand, we further ... Category 1: Applications -- OR and Management Sciences (Supply ...
Specific heat at constant volume in the thermodynamic model
C. B. Das; S. Das Gupta; A. Z. Mekjian
2003-07-04
A thermodynamic model for multifragmentation which is frequently used appears to give very different values for specific heat at constant volume depending upon whether canonical or grand canonical ensemble is used. The cause for this discrepancy is analysed.
Constant displacement rate experiments and constitutive modeling of asphalt mixtures
Hariharakumar, Pradeep
2006-04-12
The focus of this dissertation is on constant displacment rate experiments on asphalt concrete and on developing continuum models in a general thermo-mechanical setting which will corroborate with the experimental results. Modeling asphalt concrete...
The Duffing Oscillator And Linearization Techniques For Its Motion Constants
Rashdan, Mouath
2014-01-16
Analyzing the characteristics of higher order nonlinear dynamic systems is really difficult. This can involve giving solutions with respect to time. Motion constants are another way of studying the behavior of the dynamic system. If the motion...
Quantumtheory of Wavefields in a Space of Constant Curvature
Gutzwiller, Martin C.
1953-01-01
KU ScholarWorks : Quantumtheory of Wavefields in a Space of Constant Curvature 1953 by Martin C. Gutzwiller This work has been made available by the University of Kansas Libraries’ Office of Scholarly Communication and Copyright. http...KU ScholarWorks : Quantumtheory of Wavefields in a Space of Constant Curvature 1953 by Martin C. Gutzwiller This work has been made available by the University of Kansas Libraries’ Office of Scholarly Communication and Copyright. http...
CODATA Recommended Values of the Fundamental Physical Constants: 2014
Mohr, Peter J; Taylor, Barry N
2015-01-01
This report gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. The recommended values may also be found on the World Wide Web at physics.nist.gov/constants.
Precision measurements of the Planck and Avogadro constants
Bettin, Horst; Man, John; Mana, Giovanni; Massa, Enrico; Picard, Alain
2013-01-01
Precision measurements of the fundamental constants are tour de force of basic metrology, where the useful information is usually beyond the last digit of the measured value. They challenge theoretical models and measurement technologies and set a network of measurement equations on which a universal system of units can be built, which stems from the most basic concepts of physics. Because of their connection with the mass unit, the Avogadro and Planck constants are on the spotlight.
Choi, Joon Ho
2007-04-25
of indoor daylight variables in type A from 8:00 AM to 6:00 PM. ...........................................................97 xiii TABLE Page 36 Summary of the average values of indoor... daylight variables in type B from 8:00 AM to 6:00 PM.............................................................98 37 Significant ALOS comparisons and average illuminance between SE and NW...
STUDY TYPES What is a "Study Type"?
Dorf, Martin E.
#12;STUDY TYPES What is a "Study Type"? A Study Type is a defined business process. Study Types work together to streamline workflow, track data & keep users informed. There are 2 Study Types in eCOMS: COMS and IACUC. The COMS Study: The COMS Study is an online form that a Principal Investigator fills
Y. V. Stadnik; V. V. Flambaum
2015-09-03
We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the induction of slow `drifts', oscillating variations and transient-in-time variations of the fundamental constants of Nature by dark matter, which offer a more natural means of producing a cosmological evolution of the fundamental constants compared with traditional dark energy-type theories, which invoke a (nearly) massless underlying field. Thus, measurements of variation of the fundamental constants gives us a new tool in dark matter searches.
Statistical theory of elastic constants of cholesteric liquid crystals
A. Kapanowski
2009-10-20
A statistical theory of cholesteric liquid crystals composed of short rigid biaxial molecules is presented. It is derived in the thermodynamic limit at a small density and a small twist. The uniaxial (biaxial) cholesteric phase is regarded as a distorted form of the uniaxial (biaxial) nematic phase. The chirality of the interactions and the implementation of the inversion to the rotation matrix elements are discussed in detail. General microscopic expressions for the elastic constants are derived. The expressions involve the one-particle distribution function and the potential energy of two-body short-range interactions. It is shown that the elastic constants determine the twist of the phase. The stability condition for the cholesteric and nematic phases is presented. The theory is used to study unary and binary systems. The temperature and concentration dependence of the order parameters, the elastic constants and the twist of the phase are obtained. The possibility of phase separation is not investigated.
Study of constant mode in charmonium correlators at finite temperature
Takashi Umeda
2007-10-01
Recent studies on the spectral function of charmonium in lattice QCD suggest survival of $J/\\psi$ state in the deconfinement phase till relatively high temperature. Based on the studies, different scenarios of $J/\\psi$ suppression are discussed to understand experimental results in the Heavy Ion Collision experiments. The scenarios require the information on the dissociation temperatures of $\\chi_c$ and $\\psi'$ as well as that of $J/\\psi$. In order to investigate these states in finite temperature lattice QCD, we have to consider an effect of a characteristic constant mode in the correlators. As a result of the study on the constant mode, we find that most drastic change in charmonium correlators for $\\chi_c$ states just above the deconfinement transition are caused by the constant mode. It may indicate the survival of $\\chi_c$ states after the deconfinement transition until, at least, $1.4T_c$.
Reaction Rate Constant for Radiative Association of CF$^+$
Öström, Jonatan; Nyman, Gunnar; Gustafsson, Magnus
2015-01-01
Reaction rate constants and cross sections are computed for the radiative association of carbon cations ($\\text{C}^+$) and fluorine atoms ($\\text{F}$) in their ground states. We consider reactions through the electronic transition $1^1\\Pi \\rightarrow X^1\\Sigma^+$ and rovibrational transitions on the $X^1\\Sigma^+$ and $a^3\\Pi$ potentials. Semiclassical and classical methods are used for the direct contribution and Breit--Wigner theory for the resonance contribution. Quantum mechanical perturbation theory is used for comparison. A modified formulation of the classical method applicable to permanent dipoles of unequally charged reactants is implemented. The total rate constant is fitted to the Arrhenius--Kooij formula in five temperature intervals with a relative difference of $10$ to $250\\:\\text{K}$, the rate constant is about $10^{-21}\\:\\text{cm}^3\\text{s}^{-1}$, rising toward $10^{-16}\\:\\text{cm}^3\\text{s}^{-1}$ fo...
Electromagnetic low-energy constants in ChPT
Christoph Haefeli; Mikhail A. Ivanov; Martin Schmid
2007-10-29
We investigate three-flavour chiral perturbation theory including virtual photons in a limit where the strange quark mass is much larger than the external momenta and the up and down quark masses, and where the external fields are those of two-flavour chiral perturbation theory. In particular we work out the strange quark mass dependence of the electromagnetic two-flavour low-energy constants C and k_i. We expect that these relations will be useful for a more precise determination of the electromagnetic low-energy constants.
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.
Proposal for new experimental schemes to realize the Avogadro constant
Biraben, F; Clad, P; Genevs, G; Gournay, P; Guellati-Khlifa, S; Julien, L; Juncar, P; De Mirandes, E; Nez, F
2006-01-01
We propose two experimental schemes to determine and so to realize the Avogadro constant $N\\_{A}$ at the level of 10$^{-7}$ or better with a watt balance experiment and a cold atom experiment measuring $h/m(X)$ (where $h$ is the Planck constant and $m(X)$ the mass of the atom $X$). We give some prospects about achievable uncertainties and we discuss the opportunity to test the existence of possible unknown correction factors for the Josephson effect and quantum Hall effect.
Low-Energy Constants from Resonance Chiral Theory
Antonio Pich
2008-12-14
I discuss the recent attempts to build an effective chiral Lagrangian incorporating massive resonance states. A useful approximation scheme to organize the resonance Lagrangian is provided by the large-Nc limit of QCD. Integrating out the resonance fields, one recovers the usual chiral perturbation theory Lagrangian with explicit values for the low-energy constants, parameterized in terms of resonance masses and couplings. The resonance chiral theory generates Green functions that interpolate between QCD and chiral perturbation theory. Analyzing these Green functions, both for large and small momenta, one gets QCD constraints on the resonance couplings and, therefore, information on the low-energy constants governing the Goldstone interactions.
Low-energy constants from ALEPH hadronic tau decay data
Boito, Diogo; Golterman, Maarten; Hudspith, Renwick; Lewis, Randy; Maltman, Kim; Peris, Santiago
2015-01-01
We determined the NLO chiral low-energy constant $L_{10}$, and various combinations of NNLO chiral low-energy constants employing recently revised ALEPH results for the non-strange vector (V) and axial-vector (A) hadronic tau decay distributions and recently updated RBC/UKQCD lattice data for the non-strange V-A two-point function. In this talk, we explain the ingredients of this determination. Our errors are at or below the level expected for contributions of yet higher order in the chiral expansion, suggesting that our results exhaust the possibilities of what can be meaningfully achieved in an NNLO analysis.
Evolving extrinsic curvature and the cosmological constant problem
Abraao J. S. Capistrano; Luiz A. Cabral
2015-12-09
The concept of smooth deformation of Riemannian manifolds associated with the extrinsic curvature is explained and applied to the FLRW cosmology. We show that such deformation can be derived from Einstein-Hilbert-like dynamical principle producing an observable effect in the sense of Noether. As a result, we notice on how the extrinsic curvature compensates both quantitative and qualitative difference between the cosmological constant $ \\Lambda$ and the vacuum energy $\\rho_{vac}$ obtaining the observed upper bound for the cosmological constant problem at electroweak scale. The topological characteristics of the extrinsic curvature are discussed showing that the produced extrinsic scalar curvature is an evolving dynamical quantity.
Calculation of the Dimer Equilibrium Constant of Heavy Water Saturated Vapor
Bulavin, L A; Makhlaichuk, V N
2015-01-01
Water is the most common substance on Earth.The discovery of heavy water and its further study have shown that the change of hydrogen for deuterium leads to the significant differences in their properties.The triple point temperature of heavy water is higher,at the same time the critical temperature is lower.Experimental values of the second virial coefficient of the EOS for the vapor of normal and heavy water differ at all temperatures.This fact can influence the values of the dimerization constant for the heavy water vapor.The equilibrium properties of the dimerization process are described with the methods of chemical thermodynamics.The chemical potentials for monomers (m) and dimers (d)are the functions of their concentrations.The interactions of monomer-dimer and dimer-dimer types are taken into account within the solution of equation for chemical potentials.The obtained expression for the dimerization constant contains the contributions of these types.The averaged potentials are modeled by the Sutherlan...
Harmonic Broadcasting Is Bandwidth-Optimal Assuming Constant Bit Rate
Sudan, Madhu
Harmonic Broadcasting Is Bandwidth-Optimal Assuming Constant Bit Rate Lars Engebretsen1, and Madhu Street Cambridge, Massachusetts 02139 USA E-mail: madhu@mit.edu November 2005 Abstract. Harmonic for video-on-demand broadcasting. In this paper, we note that harmonic broadcasting is actually a spe- cial
Constant Sustainable Consumption Rate in Optimal Growth with Exhaustible Resources*
Wan, Frederic Yui-Ming
;48 Frederic Y. M. Wan resources which are essential to the production of consumption goods. To those concernedConstant Sustainable Consumption Rate in Optimal Growth with Exhaustible Resources* By Frederic Y's criterion of maximum sustainable consumption rate, previously formulated as a minimum
Strategic Plan 2012 The Constant Pursuit of Discovery
Harms, Kyle E.
Strategic Plan 2012 1 The Constant Pursuit of Discovery 2012 Strategic Plan To support a holistic thrive and support the LSU Flagship 2020 Agenda. #12;Strategic Plan 2012 2 #12;Strategic Plan 2012 3, Sea and Space Grant university in the Nation. Thus the ORED strategic plan targets the areas
Codes of constant Lee or Euclidean weight Jay A. Wood
Wood, Jay
Codes of constant Lee or Euclidean weight Jay A. Wood Department of Mathematics, Computer Science & Statistics Purdue University Calumet Hammond, Indiana 46323--2094 USA wood@calumet.purdue.edu http://www.calumet.purdue.edu/public/math/wood Scholarly Research Awards. #12; JAY A. WOOD 1. Linear codes as modules Throughout this extended abstract
Efficient Constant-Velocity Reconfiguration of Crystalline Robots
O'Rourke, Joseph
Efficient Constant-Velocity Reconfiguration of Crystalline Robots Greg Aloupis S appeared at WAFR 2008 [Aloupis et al., 2008a], with title Realistic Reconfiguration of Crystalline (and in [Murata and Kurokawa, 2007, Yim et al., 2007]. In this paper we focus on the (modular) Crystalline [Rus
Secure and Constant Cost Public Cloud Storage Auditing with Deduplication
International Association for Cryptologic Research (IACR)
Secure and Constant Cost Public Cloud Storage Auditing with Deduplication Jiawei Yuan Department and secure data integrity auditing with storage deduplication for cloud storage. In this paper we solve and storage efficiency are two important requirements for cloud storage. Proof of Retriev- ability (POR
Two-component equations modelling water waves with constant vorticity
Joachim Escher; David Henry; Boris Kolev; Tony Lyons
2014-09-30
In this paper we derive a two-component system of nonlinear equations which model two-dimensional shallow water waves with constant vorticity. Then we prove well-posedness of this equation using a geometrical framework which allows us to recast this equation as a geodesic flow on an infinite dimensional manifold. Finally, we provide a criteria for global existence.
DATA SUMMARIES The measured values of fundamental constants become more
Boal, David
that a mole contains 6.022 x 1023 atoms, a number referred to as Avogadro's number. The usefulness of the mole mass] 1.6750 x 10-27 kg kB [Boltzmann's constant] 1.38 x 10-23 J/Ko No [Avogadro's number] 6.022 x 1023
Stability of Adhesion Clusters under Constant Force T. Erdmann1
Schwarz, Ulrich
Stability of Adhesion Clusters under Constant Force T. Erdmann1 and U. S. Schwarz1,2 1 Max Planck. This effect might be used by cell-matrix adhesions to induce signaling events through cytoskeletal loading matrix and to each other through clusters of adhesion molecules. The number of receptors in adhesion
Temperature and moisture dependence of dielectric constant for silica aerogels
Hrubesh, L.H., LLNL
1997-03-01
The dielectric constants of silica aerogels are among the lowest measured for any solid material. The silica aerogels also exhibit low thermal expansion and are thermally stable to temperatures exceeding 500{degrees}C. However, due to the open porosity and large surface areas for aerogels, their dielectric constants are strongly affected by moisture and temperature. This paper presents data for the dielectric constants of silica aerogels as a function of moisture content at 25{degrees}C, and as a function of temperature, for temperatures in the range from 25{degrees}C to 450{degrees}C. Dielectric constant data are also given for silica aerogels that are heat treated in dry nitrogen at 500{degrees}C, then cooled to 25{degrees}C for measurements in dry air. All measurements are made on bulk aerogel spheres at 22GHz microwave frequency, using a cavity perturbation method. The results of the dependence found here for bulk materials can be inferred to apply also to thin films of silica aerogels having similar nano-structures and densities.
Optical constants of carbon dioxide ice Stephen G. Warren
Warren, Stephen
Optical constants of carbon dioxide ice Stephen G. Warren Laboratory measurements of the absorption. At pressures belowthe triple point (5.2atm), carbon dioxide exists only as a gas or solid. The sublimation in the ultraviolet (50-130-nm wavelength) due to elec- tronic transitions. It is relatively transparent
Lower Bounds on Interactive Compressibility by Constant-Depth Circuits
Edinburgh, University of
Lower Bounds on Interactive Compressibility by Constant-Depth Circuits Arkadev Chattopadhyay to prove the first lower bounds on general probabilistic multi-round instance compression. We show, and strengthens results of Dubrov and Ishai [DI06]. We also show that a similar lower bound holds for Majority. We
University of Technology, Sydney
Assignment Types UTS LIBRARY February 2013 Academic Writing Guide Part 2 Assignment Types: This section outlines the basic types of written assignments, providing structural elements and examples. #12;2 II. Assignment Types 1. Essay Writing
A Typed Operational Semantics for Type Theory
Goguen, Healfdene
Untyped reduction provides a natural operational semantics for type theory. Normalization results say that such a semantics is sound. However, this reduction does not take type information into account and gives no information ...
New process to avoid emissions: Constant pressure in coke ovens
Giertz, J.; Huhn, F. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). Inst. for Cokemaking and Fuel Technology; Hofherr, K. [Thyssen Stahl AG, Duisburg (Germany)
1995-12-01
A chamber pressure regulation (PROven), especially effective in regard to emission control problems of coke ovens is introduced for the first time. Because of the partial vacuum in the collecting main system, it is possible to keep the oven`s raw gas pressure constant on a low level over the full coking time. The individual pressure control for each chamber is assured directly as a function of the oven pressure by an immersion system controlling the flow resistance of the collecting main valve. The latter is a fixed-position design (system name ``FixCup``). By doing away with the interdependence of collecting main pressure and chamber pressure, a parameter seen as a coking constant could not be made variable. This opens a new way to reduce coke oven emissions and simultaneously to prevent the ovens from damage caused by air ingress into the oven.
Predicting Stability Constants for Uranyl Complexes Using Density Functional Theory
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vukovic, Sinisa; Hay, Benjamin P.; Bryantsev, Vyacheslav S.
2015-04-02
The ability to predict the equilibrium constants for the formation of 1:1 uranyl:ligand complexes (log K1 values) provides the essential foundation for the rational design of ligands with enhanced uranyl affinity and selectivity. We also use density functional theory (B3LYP) and the IEFPCM continuum solvation model to compute aqueous stability constants for UO22+ complexes with 18 donor ligands. Theoretical calculations permit reasonably good estimates of relative binding strengths, while the absolute log K1 values are significantly overestimated. Accurate predictions of the absolute log K1 values (root mean square deviation from experiment 1 values ranging from 0more »to 16.8) can be obtained by fitting the experimental data for two groups of mono and divalent negative oxygen donor ligands. The utility of correlations is demonstrated for amidoxime and imide dioxime ligands, providing a useful means of screening for new ligands with strong chelate capability to uranyl.« less
$\\hbar$ as a Physical Constant of Classical Optics and Electrodynamics
Tremblay, Real; Allen, Claudine Ni
2015-01-01
The Planck constant ($\\hbar$) plays a pivotal role in quantum physics. Historically, it has been proposed as postulate, part of a genius empirical relationship $E=\\hbar \\omega$ in order to explain the intensity spectrum of the blackbody radiation for which classical electrodynamic theory led to an unacceptable prediction: The ultraviolet catastrophe. While the usefulness of the Planck constant in various fields of physics is undisputed, its derivation (or lack of) remains unsatisfactory from a fundamental point of view. In this paper, the analysis of the blackbody problem is performed with a series expansion of the electromagnetic field in terms of TE, TM modes in a metallic cavity with small losses, that leads to developing the electromagnetic fields in a \\textit{complete set of orthonormal functions}. This expansion, based on coupled power theory, maintains both space and time together enabling modeling of the blackbody's evolution toward equilibrium. Reaching equilibrium with a multimodal waveguide analysi...
Spectral Properties and Dynamical Tunneling in Constant-Width Billiards
B. Dietz; T. Guhr; B. Gutkin; M. Miski-Oglu; A. Richter
2014-07-24
We determine with unprecedented accuracy the lowest 900 eigenvalues of two quantum constant-width billiards from resonance spectra measured with flat, superconducting microwave resonators. While the classical dynamics of the constant-width billiards is unidirectional, a change of the direction of motion is possible in the corresponding quantum system via dynamical tunneling. This becomes manifest in a splitting of the vast majority of resonances into doublets of nearly degenerate ones. The fluctuation properties of the two respective spectra are demonstrated to coincide with those of a random-matrix model for systems with violated time-reversal invariance and a mixed dynamics. Furthermore, we investigate tunneling in terms of the splittings of the doublet partners. On the basis of the random-matrix model we derive an analytical expression for the splitting distribution which is generally applicable to systems exhibiting dynamical tunneling between two regions with (predominantly) chaotic dynamics.
Is there further evidence for spatial variation of fundamental constants?
Berengut, J. C.; Flambaum, V. V.; King, J. A.; Curran, S. J.; Webb, J. K.
2011-06-15
Indications of spatial variation of the fine-structure constant, {alpha}, based on study of quasar absorption systems have recently been reported [J. K. Webb, J. A. King, M. T. Murphy, V. V. Flambaum, R. F. Carswell, and M. B. Bainbridge, arXiv:1008.3907.]. The physics that causes this {alpha}-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis and study existing measurements of deuterium abundance for a signal. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio {mu} and x={alpha}{sup 2{mu}}g{sub p} for spatial variation.
Constant-Optimized Quantum Circuits for Modular Multiplication and Exponentiation
Igor L. Markov; Mehdi Saeedi
2015-04-02
Reversible circuits for modular multiplication $Cx$%$M$ with $x
Defect density and dielectric constant in perovskite solar cells
Samiee, Mehran; Konduri, Siva; Abbas, Hisham A.; Joshi, Pranav; Zhang, Liang; Dalal, Vikram; Ganapathy, Balaji; Kottokkaran, Ranjith; Noack, Max; Kitahara, Andrew
2014-10-13
We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH{sub 3}NH{sub 3}PbI{sub x}Cl{sub 1?x} perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66?eV below the conduction band and one at 0.24?eV below the conduction band. The attempt to escape frequency is in the range of 2?×?10{sup 11}/s. Quantum efficiency data indicate a bandgap of 1.58?eV. Urbach energies of valence and conduction band are estimated to be ?16 and ?18?meV. Measurement of saturation capacitance indicates that the relative dielectric constant is ?18.
Sidestepping the Cosmological Constant with Football-Shaped Extra Dimensions
Sean M. Carroll; Monica M. Guica
2003-02-11
We present an exact solution for a factorizable brane-world spacetime with two extra dimensions and explicit brane sources. The compactification manifold has the topology of a two-sphere, and is stabilized by a bulk cosmological constant and magnetic flux. The geometry of the sphere is locally round except for conical singularities at the locations of two antipodal branes, deforming the sphere into an American-style football. The bulk magnetic flux needs to be fine-tuned to obtain flat geometry on the branes. Once this is done, the brane geometry is insensitive to the brane vacuum energy, which only affects the conical deficit angle of the extra dimensions. Solutions of this form provide a new arena in which to explore brane-world phenomenology and the effects of extra dimensions on the cosmological constant problem.
Mega-masers, Dark Energy and the Hubble Constant
Lo, Fred K. Y.
2007-10-15
Powerful water maser emission (water mega-masers) can be found in accretion disks in the nuclei of some galaxies. Besides providing a measure of the mass at the nucleus, such mega-masers can be used to determine the distance to the host galaxy, based on a kinematic model. We will explain the importance of determining the Hubble Constant to high accuracy for constraining the equation of state of Dark Energy and describe the Mega-maser Cosmology Project that has the goal of determining the Hubble Constant to better than 3%. Time permitting, we will also present the scientific capabilities of the current and future NRAO facilities: ALMA, EVLA, VLBA and GBT, for addressing key astrophysical problems
Thermodynamics of de Sitter Black Holes: Thermal Cosmological Constant
Yuichi Sekiwa
2006-04-10
We study the thermodynamic properties associated with the black hole event horizon and the cosmological horizon for black hole solutions in asymptotically de Sitter spacetimes. We examine thermodynamics of these horizons on the basis of the conserved charges according to Teitelboim's method. In particular, we have succeeded in deriving the generalized Smarr formula among thermodynamical quantities in a simple and natural way. We then show that cosmological constant must decrease when one takes into account the quantum effect. These observations have been obtained if and only if cosmological constant plays the role of a thermodynamical state variable. We also touch upon the relation between inflation of our universe and a phase transition of black holes.
Estimation of the effective distribution coefficient from the solubility constant
Wang, Yug-Yea; Yu, C.
1994-07-01
An updated version of RESRAD has been developed by Argonne National Laboratory for the US Department of Energy to derive site-specific soil guidelines for residual radioactive material. In this updated version, many new features have been added to the, RESRAD code. One of the options is that a user can input a solubility constant to limit the leaching of contaminants. The leaching model used in the code requires the input of an empirical distribution coefficient, K{sub d}, which represents the ratio of the solute concentration in soil to that in solution under equilibrium conditions. This paper describes the methodology developed to estimate an effective distribution coefficient, Kd, from the user-input solubility constant and the use of the effective K{sub d} for predicting the leaching of contaminants.
The Ds and D+ Leptonic Decay Constants from Lattice QCD
A. Bazavov; C. Bernard; C. DeTar; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. X. El-Khadra; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; M. Di Pierro; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water
2009-12-28
We present the leptonic decay constants fDs and fD+ computed on the MILC collaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks with the Fermilab interpretation and improved staggered light quarks. The simultaneous chiral and continuum extrapolation, which determines both decay constants, includes partially-quenched lattice results at lattice spacings a ~ 0:09, 0:12 and 0:15 fm. We have made several recent improvements in our analysis: a) we include terms in the fit describing leading order heavy-quark discretization effects, b) we have adopted a more precise input r1 value consistent with our other D and B meson studies, c) we have retuned the input bare charm masses based upon the new r1. Our preliminary results are fDs = 260 +/-10 MeV and fD+ = 217 +/-10 MeV.
Confined Dirac Particles in Constant and Tilted Magnetic Field
Abdulaziz D. Alhaidari; Hocine Bahlouli; Ahmed Jellal
2012-02-23
We study the confinement of charged Dirac particles in 3+1 space-time due to the presence of a constant and tilted magnetic field. We focus on the nature of the solutions of the Dirac equation and on how they depend on the choice of vector potential that gives rise to the magnetic field. In particular, we select a "Landau gauge" such that the momentum is conserved along the direction of the vector potential yielding spinor wavefunctions, which are localized in the plane containing the magnetic field and normal to the vector potential. These wave functions are expressed in terms of the Hermite polynomials. We point out the relevance of these findings to the relativistic quantum Hall effect and compare with the results obtained for a constant magnetic field normal to the plane in 2+1 dimensions.
The strong coupling constant at low Q^2
Alexandre Deur
2005-06-06
We extract an effective strong coupling constant using low-Q{sup 2} data and sum rules. Its behavior is established over the full Q{sup 2}-range and is compared to calculations based on lattice QCD, Schwinger-Dyson equations and a quark model. Although the connection between all these quantities is not known yet, the results are surprisingly alike. Such a similitude may be related to quark-hadron duality.
Turbine blade having a constant thickness airfoil skin
Marra, John J
2012-10-23
A turbine blade is provided for a gas turbine comprising: a support structure comprising a base defining a root of the blade and a framework extending radially outwardly from the base, and an outer skin coupled to the support structure framework. The skin has a generally constant thickness along substantially the entire radial extent thereof. The framework and the skin define an airfoil of the blade.
Apparatus producing constant cable tension for intermittent demand
Lauritzen, T.
1984-05-23
This invention relates to apparatus for producing constant tension in cable or the like when it is unreeled and reeled from a drum or spool under conditions of intermittent demand. The invention is particularly applicable to the handling of superconductive cable, but the invention is also applicable to the unreeling and reeling of other strands, such as electrical cable, wire, cord, other cables, fish line, wrapping paper and numerous other materials.
Constraining fundamental constant evolution with HI and OH lines
N. Kanekar; G. I. Langston; J. T. Stocke; C. L. Carilli; K. L. Menten
2012-01-16
We report deep Green Bank Telescope spectroscopy in the redshifted HI 21cm and OH 18cm lines from the $z = 0.765$ absorption system towards PMN J0134-0931. A comparison between the "satellite" OH 18cm line redshifts, or between the redshifts of the HI 21cm and "main" OH 18cm lines, is sensitive to changes in different combinations of three fundamental constants, the fine structure constant $\\alpha$, the proton-electron mass ratio $\\mu \\equiv m_p/m_e$ and the proton g-factor $g_p$. We find that the satellite OH 18cm lines are not perfectly conjugate, with both different line shapes and stronger 1612 MHz absorption than 1720 MHz emission. This implies that the satellite lines of this absorber are not suitable to probe fundamental constant evolution. A comparison between the redshifts of the HI 21cm and OH 18cm lines, via a multi-Gaussian fit, yields the strong constraint $[\\Delta F/F] = [-5.2 \\pm 4.3] \\times 10^{-6}$, where $F \\equiv g_p [\\mu \\alpha^2]^{1.57}$ and the error budget includes contributions from both statistical and systematic errors. We thus find no evidence for a change in the constants between $z = 0.765$ and the present epoch. Incorporating the constraint $[\\Delta \\mu/\\mu ] < 3.6 \\times 10^{-7}$ from another absorber at a similar redshift and assuming that fractional changes in $g_p$ are much smaller than those in $\\alpha$, we obtain $[\\Delta \\alpha/\\alpha ] = (-1.7 \\pm 1.4) \\times 10^{-6}$ over a lookback time of 6.7 Gyrs.
Numerical computation of constant mean curvature surfaces using finite elements
Jan Metzger
2004-08-18
This paper presents a method for computing two-dimensional constant mean curvature surfaces. The method in question uses the variational aspect of the problem to implement an efficient algorithm. In principle it is a flow like method in that it is linked to the gradient flow for the area functional, which gives reliable convergence properties. In the background a preconditioned conjugate gradient method works, that gives the speed of a direct elliptic multigrid method.
Determining coal permeabilities through constant pressure production interference testing
Schubarth, Stephen Kurt
1983-01-01
COMPUTER TEST NO. 2. . . Page 3 RESULTS OF COMPUTER SIMULATION TEST DATA ANALYSIS. . . . . . 16 4 GRID PATTERN BREAKUP USED IN RESERVOIR SIMULATOR TESTS 18 5 SIMULATOR INPUT PARAMETERS REMAINING CONSTANT. . . 6 FINE GRID BREAKUP USED IN MODEL... to the diffusivity equation. & A variety of both inner and outer boundary conditions were investigated. The diffusivity equation appeared in the following form. a r2 r 3 r at . 002637 Solutions to this equation were derived assuming that a slightly compressible...
Adams, Amy Lynn
2011-01-01
This thesis evaluates the constant rate of strain and constant head techniques for measurement of the hydraulic conductivity of fine grained soils. A laboratory program compares hydraulic conductivity measurements made ...
Stars In Other Universes: Stellar structure with different fundamental constants
Fred C. Adams
2008-07-23
Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem tractable, we develop a semi-analytical stellar structure model that allows for physical understanding of these stars with unconventional parameters, as well as a means to survey the relevant parameter space. In this work, the most important quantities that determine stellar properties -- and are allowed to vary -- are the gravitational constant $G$, the fine structure constant $\\alpha$, and a composite parameter $C$ that determines nuclear reaction rates. Working within this model, we delineate the portion of parameter space that allows for the existence of stars. Our main finding is that a sizable fraction of the parameter space (roughly one fourth) provides the values necessary for stellar objects to operate through sustained nuclear fusion. As a result, the set of parameters necessary to support stars are not particularly rare. In addition, we briefly consider the possibility that unconventional stars (e.g., black holes, dark matter stars) play the role filled by stars in our universe and constrain the allowed parameter space.
Electronic transport in two-dimensional high dielectric constant nanosystems
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ortuño, M.; Somoza, A. M.; Vinokur, V. M.; Baturina, T. I.
2015-04-10
There has been remarkable recent progress in engineering high-dielectric constant two dimensional (2D) materials, which are being actively pursued for applications in nanoelectronics in capacitor and memory devices, energy storage, and high-frequency modulation in communication devices. Yet many of the unique properties of these systems are poorly understood and remain unexplored. Here we report a numerical study of hopping conductivity of the lateral network of capacitors, which models two-dimensional insulators, and demonstrate that 2D long-range Coulomb interactions lead to peculiar size effects. We find that the characteristic energy governing electronic transport scales logarithmically with either system size or electrostatic screeningmore »length depending on which one is shorter. Our results are relevant well beyond their immediate context, explaining, for example, recent experimental observations of logarithmic size dependence of electric conductivity of thin superconducting films in the critical vicinity of superconductor-insulator transition where a giant dielectric constant develops. Our findings mark a radical departure from the orthodox view of conductivity in 2D systems as a local characteristic of materials and establish its macroscopic global character as a generic property of high-dielectric constant 2D nanomaterials.« less
Hydrogen Atom and Time Variation of Fine-Structure Constant
Mu-Lin Yan
2009-11-21
In this paper, we have solved the de Sitter special relativistic ($\\mathcal{SR}_{cR}$-) Dirac equation of hydrogen in the earth-QSO(quasar) framework reference by means of the adiabatic approach. The aspects of geometry effects of de Sitter space-time described by Beltrami metric are explored and taken into account. It is found that the $\\mathcal{SR}_{cR}$-Dirac equation of hydrogen is a time dependent quantum Hamiltonian system. We provide an explicit calculation to justify the adiabatic approach in dealing with this time-dependent system. Since the radius of de Sitter sphere $R$ is cosmologically large, the evolution of the system is very slow so that the adiabatic approximation legitimately works with high accuracy. We conclude that the electromagnetic fine-structure constant, the electron mass and the Planck constant are time variations. This prediction of fine-structure constant is consistent with the presently available observation data. For confirming it further, experiments/observations are required.
The Effective Fine Structure Constant at TESLA Energies
F. Jegerlehner
2001-05-27
We present a new estimate of the hadronic contribution to the shift in the fine structure constant at LEP and TESLA energies and calculate the effective fine structure constant. Substantial progress in a precise determination of this important parameter is a consequence of substantially improved total cross section measurements by the BES II collaboration and an improved theoretical understanding. In the standard approach which relies to a large extend on experimental data we find $\\Delta \\al_{\\rm hadrons}^{(5)}(\\mz) = 0.027896 \\pm 0.000395$ which yields $\\alpha^{-1}(\\mz) = 128.907 \\pm 0.054$. Another approach, using the Adler function as a tool to compare theory and experiment, allows us to to extend the applicability of perturbative QCD in a controlled manner. The result in this case reads $\\Delta\\alpha^{(5)}_{\\rm had}(M_Z^2) = 0.027730 \\pm 0.000209$ and hence $\\alpha^{-1}(\\mz) = 128.930 \\pm 0.029$. At TESLA energies a new problem shows up with the definition of an effective charge. A possible solution of the problem is presented. Prospects for further progress in a precise determination of the effective fine structure constant are discussed.
Simulations Data Simulation Type
Wang, Xiaorui "Ray"
, are unreliable because they have to constantly be calibrated to match actual energy usage data. Currently their Facebook accounts. This was utilized using a Drupal for Facebook module that integrates Facebook user
On the Definitions of Entanglement Spacing and Time Constants in the Tube R.G. Larson*
quantities, including the temperature T, Boltzmann's constant kB, and Avogadro's number NA, from which
The variation of the fine-structure constant from disformal couplings
van de Bruck, Carsten; Nunes, Nelson J
2015-01-01
We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, alpha. As a result, the theory we consider can explain the non-zero reported variation in the evolution of alpha by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of alpha. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical r...
Broader source: Energy.gov [DOE]
Several commissioning types exist to address the specific needs of equipment and systems across both new and existing buildings. The following commissioning types provide a good overview.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Appointment Types Postdoc Appointment Types Most postdocs will be offered a postdoctoral research associate appointment. Each year, approximately 30 Postdoctoral Fellow...
Critical behaviors of black hole in an asymptotically safe gravity with cosmological constant
Ma, Meng-Sen
2014-01-01
We study the $P-V/r_{+}$ criticality and phase transition of quantum-corrected black hole in asymptotic safety (AS) gravity in the extended phase space. For the black hole, the cosmological constant is dependent on the momentum cutoff or energy scale, therefore one can naturally treat it as a variable and connect it with the thermodynamic pressure. We find that for the quantum-corrected black hole there is a similar first-order phase transition to that of the van der Waals liquid/gas system. We also analyze the types of the phase transition at the critical points according to Ehrenfest's classification. It is shown that they are second-order phase transition.
Evaluation of the cosmological constant in inflation with a massive non-minimal scalar field
Jung-Jeng Huang
2015-09-29
In Schroedinger picture we study the possible effects of trans-Planckian physics on the quantum evolution of massive non-minimally coupled scalar field in de Sitter space. For the nonlinear Corley-Jacobson type dispersion relations with quartic or sextic correction, we obtain the time evolution of the vacuum state wave functional during slow-roll inflation, and calculate explicitly the corresponding expectation value of vacuum energy density. We find that the vacuum energy density is finite. For the usual dispersion parameter choice, the vacuum energy density for quartic correction to the dispersion relation is larger than for sextic correction, while for some other parameter choices, the vacuum energy density for quartic correction is smaller than for sextic correction. We also use the backreaction to constrain the magnitude of parameters in nonlinear dispersion relation, and show how the cosmological constant depends on the parameters and the energy scale during the inflation at the grand unification phase transition.
Evaluation of the cosmological constant in inflation with a massive non-minimal scalar field
Huang, Jung-Jeng
2015-01-01
In Schroedinger picture we study the possible effects of trans-Planckian physics on the quantum evolution of massive non-minimally coupled scalar field in de Sitter space. For the nonlinear Corley-Jacobson type dispersion relations with quartic or sextic correction, we obtain the time evolution of the vacuum state wave functional during slow-roll inflation, and calculate explicitly the corresponding expectation value of vacuum energy density. We find that the vacuum energy density is finite. For the usual dispersion parameter choice, the vacuum energy density for quartic correction to the dispersion relation is larger than for sextic correction, while for some other parameter choices, the vacuum energy density for quartic correction is smaller than for sextic correction. We also use the backreaction to constrain the magnitude of parameters in nonlinear dispersion relation, and show how the cosmological constant depends on the parameters and the energy scale during the inflation at the grand unification phase ...
Spectra of magnetic chain graphs: coupling constant perturbations
Pavel Exner; Stepan S. Manko
2014-12-18
We analyze spectral properties of a quantum graph in the form of a ring chain with a $\\delta$ coupling in the vertices exposed to a homogeneous magnetic field perpendicular to the graph plane. We find the band spectrum in the case when the chain exhibits a translational symmetry and study the discrete spectrum in the gaps resulting from changing a finite number of vertex coupling constants. In particular, we discuss in details some examples such as perturbations of one or two vertices, weak perturbation asymptotics, and a pair of distant perturbations.
Photon propagation in noncommutative QED with constant external field
R. Fresneda; D. M. Gitman; A. E. Shabad
2015-01-20
We find dispersion laws for the photon propagating in the presence of mutually orthogonal constant external electric and magnetic fields in the context of the $\\theta $-expanded noncommutative QED. We show that there is no birefringence to the first order in the noncommutativity parameter $% \\theta .$ By analyzing the group velocities of the photon eigenmodes we show that there occurs superluminal propagation for any direction. This phenomenon depends on the mutual orientation of the external electromagnetic fields and the noncommutativity vector. We argue that the propagation of signals with superluminal group velocity violates causality in spite of the fact that the noncommutative theory is not Lorentz-invariant and speculate about possible workarounds.
Big bang nucleosynthesis as a probe of fundamental "constants"
Thomas Dent; Steffen Stern
2007-10-25
Big Bang nucleosynthesis (BBN) is the earliest sensitive probe of the values of many fundamental particle physics parameters. We have found the leading linear dependences of primordial abundances on all relevant parameters of the standard BBN code, including binding energies and nuclear reaction rates. This enables us to set limits on possible variations of fundamental parameters. We find that 7Li is expected to be significantly more sensitive than other species to many fundamental parameters, a result which also holds for variations of coupling strengths in grand unified (GUT) models. Our work also indicates which areas of nuclear theory need further development if the values of ``constants'' are to be more accurately probed.
Confined System with Rashba Coupling in Constant Magnetic Field
Mohammed El Bouziani; Rachid Houca; Ahmed Jellal
2012-04-30
We study a two dimensional system of electrons with Rashba coupling in the constant magnetic field $B$ and confining potential. We algebraically diagonalize the corresponding Hamiltonian to end up with the solutions of the energy spectrum. In terms of two kinds of operator we construct two symmetries and discuss the filling of the shells with electrons for strong and weak $B$. Subsequently, we show that our system is sharing some common features with quantum optics where the exact operator solutions for the basics Jaynes-Cummings variables are derived from our results. An interesting limit is studied and the corresponding quantum dynamics is recovered.
Types of Lights Types of Lights
1 Types of Lights Types of Lights q So far we have studied point lights Radiate in all direc7ons q Other lights Direc7onal lights (posi7on-independent) Spotlights #12;2 Direc1onal Lights q Shine in a single, uniform direc7on q All rays
Higgs coupling constants as a probe of new physics
Kanemura, Shinya; Okada, Yasuhiro; Senaha, Eibun; Yuan, C.-P.
2004-12-01
We study new physics effects on the couplings of weak gauge bosons with the lightest CP-even Higgs boson (h), hZZ, and the trilinear coupling of the lightest Higgs boson, hhh, at the one-loop order, as predicted by the two Higgs doublet model. Those renormalized coupling constants can deviate from the standard model (SM) predictions due to two distinct origins: the tree level mixing effect of Higgs bosons and the quantum effect of additional particles in loop diagrams. The latter can be enhanced in the renormalized hhh coupling constant when the additional particles show the nondecoupling property. Therefore, even in the case where the hZZ coupling is close to the SM value, deviation in the hhh coupling from the SM value can become as large as plus 100%, while that in the hZZ coupling is at most minus 1% level. Such large quantum effect on the Higgs trilinear coupling is distinguishable from the tree level mixing effect, and is expected to be detectable at a future linear collider.
Energy Levels Of Hydrogen-Like Atomsand Fundamental Constants
Valeri V. Dvoeglazov; Rudolf N. Faustov; Yuri N. Tyukhtyaev
1994-03-27
The present review includes the description of theoretical methods for the investigations of the spectra of hydrogen-like systems. Various versions of the quasipotential approach and the method of the effective Dirac equation are considered. The new methods, which have been developed in the eighties, are described. These are the method for the investigation of the spectra by means of the quasipotential equation with the relativistic reduced mass and the method for a selection of the logarithmic corrections by means of the renormalization group equation. The special attention is given to the construction of a perturbation theory and the selection of graphs, whereof the contributions of different orders of $\\alpha$, the fine structure constant, to the energy of the fine and hyperfine splitting in a positronium, a muonium and a hydrogen atom could be calculated. In the second part of this article the comparison of the experimental results and the theoretical results concerning the wide range of topics is produced. They are the fine and hyperfine splitting in the hydrogenic systems, the Lamb shift and the anomalous magnetic moments of an electron and a muon. Also, the problem of the precision determination of a numerical value of the fine structure constant, connected with the above topics, is discussed.
Silica aerogel: An intrinsically low dielectric constant material
Hrubesh, L.W.
1995-04-01
Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.
Charmed and light pseudoscalar meson decay constants from HISQ simulations
A. Bazavov; C. Bernard; C. Bouchard; C. DeTar; D. Du; A. X. El-Khadra; J. Foley; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. Kim; J. Komijani; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; J. N. Simone; R. L. Sugar; D. Toussaint; R. S. Van de Water; R. Zhou
2014-11-10
We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$, and the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD. We use the MILC highly improved staggered quark (HISQ) ensembles with four dynamical quark flavors. Our primary results are $f_{D^+} = 212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} = 249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} = 1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total systematic, respectively. We also obtain $f_{K^+}/f_{\\pi^+} = 1.1956(10)({}^{+26}_{-18})$, updating our previous result, and determine the quark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and $m_c/m_s = 11.747(19)({}^{+59}_{-43})$. When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements $|V_{us}| = 0.22487(51) (29)(20)(5)$, $|V_{cd}|=0.217(1) (5)(1)$ and $|V_{cs}|= 1.010(5)(18)(6)$, where the errors are from this calculation of the decay constants, the uncertainty in the experimental decay rates, structure-dependent electromagnetic corrections, and, in the case of $|V_{us}|$, the uncertainty in $|V_{ud}|$, respectively.
Constant time worker thread allocation via configuration caching...
Office of Scientific and Technical Information (OSTI)
Date: 2014-11-04 OSTI Identifier: 1163186 Report Number(s): 8,881,159 13070,811 DOE Contract Number: B554331 Resource Type: Patent Research Org: International Business Machine...
Zero-Branes, Quantum Mechanics and the Cosmological Constant
Andrew Chamblin; Neil D. Lambert
2001-07-25
We analyse some dynamical issues in a modified type IIA supergravity, recently proposed as an extension of M-theory that admits de Sitter space. In particular we find that this theory has multiple zero-brane solutions. This suggests a microscopic quantum mechanical matrix description which yields a massive deformation of the usual M(atrix) formulation of M-theory and type IIA string theory.
Effect of lattice deformation on exchange coupling constants in Cr{sub 2}O{sub 3}
Kota, Yohei; Imamura, Hiroshi; Sasaki, Munetaka
2014-05-07
We studied lattice deformation effect on exchange interaction in the corundum-type Cr{sub 2}O{sub 3} theoretically. First-principles electronic structure calculations were performed to evaluate the total energy and exchange coupling constants of Cr{sub 2}O{sub 3} under lattice deformation. We found that a few percent elastic deformation is expected via misfit strain and that the first- and second-nearest neighbor exchange coupling constants of Cr{sub 2}O{sub 3} strongly depend on the lattice deformation. These results imply a possibility for improving the thermal stability of Cr{sub 2}O{sub 3} based magnetoelectric devices by lattice deformation.
Fluctuation of an ion beam extracted from an AC filament driven Bernas-type ion source
Miyamoto, N. Okajima, Y.; Wada, M.
2014-02-15
Argon ion beam fluctuation from an AC filament driven Bernas-type ion source is observed. The ion beam was measured by an 8 measurement elements beam profile monitor. The amplitude of the beam current fluctuation stayed in the same level from 100 Hz to 1 kHz of the filament heating frequency. The beam current fluctuation frequency measured by the beam profile monitor was equal to the frequency of the AC filament operation. The fluctuation amplitudes of the beam current by AC operation were less than 7% and were in the same level of the DC operation.
Zhang, WJ "Chris"
the dynamic model of the five-bar hybrid mechanism including its electric motors. Section 3 presents to which constraints are applied. In the planar five-bar mechanism (Fig. 1), the free system is two open the tracking performance of the hybrid system. A five-bar linkage with two degrees of freedom is used
Second Law Analysis of Constant Temperature Diesel Combustion
Druecke, Dr. Ben [University of Wisconsin; Foster, Prof. Dave [University of Wisconsin; Klein, Prof. Sandy [University of Wisconsin; Daw, C Stuart [ORNL; Chakravarthy, Veerathu K [ORNL; Graves, Ronald L [ORNL
2006-01-01
The results from a second law analysis of a constant temperature diesel combustion process are presented and show that this process is not significantly more reversible than conventional combustion. In addition to quantifying the total availability destruction in combustion, the magnitudes of the combustion irreversibilities attributable to each irreversible subprocess (mixing, oxidation and internal heat transfer) were determined. The primary contributor to combustion irreversibilities is the thermal interaction of reacting and non-reacting species during the oxidation and internal thermal energy transfer subprocesses. Increasing combustion temperature significantly decreases availability destruction by making the oxidation and internal thermal energy transfer processes more reversible. While increasing combustion temperature decreases combustion irreversibility, it also results in an increase in exhaust temperature. A tradeoff exists between large availability destruction at low combustion temperatures and large amounts of availability discarded in the exhaust at high combustion temperatures. The optimum amount of work was found to occur for a combustion temperature of approximately 1600 K.
Constant power speed range extension of surface mounted PM motors
Lawler, Jack Steward (Knoxville, TN); Bailey, John Milton (Knoxville, TN)
2001-01-01
A circuit and method for controlling a rotating machine (11) in the constant horsepower range above base speed uses an inverter (15) having SCR's (T1-T6) connected in series with the primary commutation switches (Q1-Q6) to control turn off of the primary commutation switches and to protect the primary commutation switches from faults. The primary commutation switches (Q1-Q6) are controlled by a controller (14), to fire in advance or after a time when the back emf equals the applied voltage, and then to turn off after a precise dwell time, such that suitable power is developed at speeds up to at least six times base speed.
Molecular Dynamics Simulations of Solutions at Constant Chemical Potential
Perego, Claudio; Parrinello, Michele
2015-01-01
Molecular Dynamics studies of chemical processes in solution are of great value in a wide spectrum of applications, that range from nano-technology to pharmaceutical chemistry. However, these calculations are affected by severe finite-size effects, such as the solution being depleted as the chemical process proceeds, that influence the outcome of the simulations. To overcome these limitations, one must allow the system to exchange molecules with a macroscopic reservoir, thus sampling a Grand-Canonical ensemble. Despite the fact that different remedies have been proposed, this still represents a key challenge in molecular simulations. In the present work we propose the C$\\mu$MD method, which introduces an external force that controls the environment of the chemical process of interest. This external force, drawing molecules from a finite reservoir, maintains the chemical potential constant in the region where the process takes place. We have applied the C$\\mu$MD method to the paradigmatic case of urea crystall...
Comment on "Mixing and Decay Constants of Pseudoscalar Mesons"
Kirchbach, M
1999-01-01
The key assumption used recently by Feldmann, Kroll and Stich [Phys.Rev. D58, 114006 (1998)] that the decay constants f_\\eta, and f_\\eta ' of the respective eta and eta ' mesons in the quark flavor basis follow the pattern of strange and non--strange quarkonia mixing in their wave functions, is reproduced in identifying the non-isotriplet part of the strong neutral axial current with the genuine axial hypercharge current J_{\\mu, 5}^Y =\\bar q \\gamma_\\mu\\gamma_5 Y/2 q, where Y=C+S+B is defined by the Gell-Mann-Nakano-Nishijima relation as the sum of charm (C), strangeness (S), and baryon (B) quark quantum numbers. The inequivalence between octet and hypercharge axial currents is pointed out.
Brownian Dynamics of charged particles in a constant magnetic field
Hou, L J; Piel, A; Shukla, P K
2009-01-01
Numerical algorithms are proposed for simulating the Brownian dynamics of charged particles in an external magnetic field, taking into account the Brownian motion of charged particles, damping effect and the effect of magnetic field self-consistently. Performance of these algorithms is tested in terms of their accuracy and long-time stability by using a three-dimensional Brownian oscillator model with constant magnetic field. Step-by-step recipes for implementing these algorithms are given in detail. It is expected that these algorithms can be directly used to study particle dynamics in various dispersed systems in the presence of a magnetic field, including polymer solutions, colloidal suspensions and, particularly complex (dusty) plasmas. The proposed algorithms can also be used as thermostat in the usual molecular dynamics simulation in the presence of magnetic field.
Vacuum Energy and Cosmological Constant Problem in Krein Quantization Approach
Pejhan, H
2014-01-01
In this paper, we consider a new version of indefinite metric field quantization called "Krein" quantization approach, where the field operators are constructed by both positive and negative energy/frequency modes, or simply physical and un-physical states. Centering on the zero-point energy, fundamental subjects revolve around this concept will be discussed. In fact the presence of un-physical states in the theory performing as natural renormalizing tools, automatically removes the infinite terms in zero-point energy and expectation value of the energy-momentum tensor, so we are capable of defining absolute meaning for energy. Thus, the method presents an interesting property linked to the cosmological constant problem. Meanwhile, in order to ensure consistency of the theory, we have studied and made comparison essential issues such as unitarity of the theory, physical achievements of renormalizing process and the trace anomaly subject.
Does Quantum Cosmology Predict a Constant Dilatonic Field?
F. G. Alvarenga; A. B. Batista; J. C. Fabris
2004-04-07
Quantum cosmology may permit to determine the initial conditions of the Universe. In particular, it may select a specific model between many possible classical models. In this work, we study a quantum cosmological model based on the string effective action coupled to matter. The Schutz's formalism is employed in the description of the fluid. A radiation fluid is considered. In this way, a time coordinate may be identified and the Wheeler-DeWitt equation reduces in the minisuperspace to a Schr\\"odinger-like equation. It is shown that, under some quite natural assumptions, the expectation values indicate a null axionic field and a constant dilatonic field. At the same time the scale factor exhibits a bounce revealing a singularity-free cosmological model. In some cases, the mininum value of the scale factor can be related to the value of gravitational coupling.
Path Integral Confined Dirac Fermions in a Constant Magnetic Field
Abdeldjalil Merdaci; Ahmed Jellal; Lyazid Chetouani
2014-04-17
We consider Dirac fermion confined in harmonic potential and submitted to a constant magnetic field. The corresponding solutions of the energy spectrum are obtained by using the path integral techniques. For this, we begin by establishing a symmetric global projection, which provides a symmetric form for the Green function. Based on this, we show that it is possible to end up with the propagator of the harmonic oscillator for one charged particle. After some transformations, we derive the normalized wave functions and the eigenvalues in terms of different physical parameters and quantum numbers. By interchanging quantum numbers, we show that our solutions possed interesting properties. The density of current and the non-relativistic limit are analyzed where different conclusions are obtained.
Confined Dirac Fermions in a Constant Magnetic Field
Ahmed Jellal; Abdulaziz D. Alhaidari; Hocine Bahlouli
2009-04-03
We obtain an exact solution of the Dirac equation in (2+1)-dimensions in the presence of a constant magnetic field normal to the plane together with a two-dimensional Dirac-oscillator potential coupling. The solution space consists of a positive and negative energy solution, each of which splits into two disconnected subspaces depending on the sign of an azimuthal quantum number, k = 0, \\pm 1, \\pm 2,... and whether the cyclotron frequency is larger or smaller than the oscillator frequency. The spinor wavefunction is written in terms of the associated Laguerre polynomials. For negative k, the relativistic energy spectrum is infinitely degenerate due to the fact that it is independent of k. We compare our results with already published work and point out the relevance of these findings to a systematic formulation of the relativistic quantum Hall effect in a confining potential.
Lieb-Liniger gas in a constant-force potential
Jukic, D.; Galic, S.; Buljan, H.; Pezer, R.
2010-08-15
We use Gaudin's Fermi-Bose mapping operator to calculate exact solutions for the Lieb-Liniger model in a linear (constant-force) potential (the constructed exact stationary solutions are referred to as the Lieb-Liniger-Airy wave functions). The ground-state properties of the gas in the wedgelike trapping potential are calculated in the strongly interacting regime by using Girardeau's Fermi-Bose mapping and the pseudopotential approach in the 1/c approximation (c denotes the strength of the interaction). We point out that quantum dynamics of Lieb-Liniger wave packets in the linear potential can be calculated by employing an N-dimensional Fourier transform as in the case of free expansion.
The Arrow of Time Forbids a Positive Cosmological Constant $?$
Laura Mersini-Houghton
2007-04-20
Motivated by the mounting evidence for dark energy, here we explore the consequences of a fundamental cosmological constant $\\Lambda$ for our universe. We show that when the gravitational entropy of a pure DeSitter state ultimately wins over matter, then the thermodynamic arrow of time in our universe must reverse in scales of order a Hubble time. We find that due to the dynamics of gravity and nonlocal entanglement, a finite size system such as a DeSitter patch with horizon size $H_0^{-1}$ has a finite lifetime $\\Delta t$. This phenomenon arises from the dynamic gravitational instabilities that develop during a DeSitter epoch and turn catastrophic. A reversed arrow of time is clearly in disagreement with observations. Thus we are led to conclude: Nature forbids a fundamental $\\Lambda$. Or else general relativity must be modified in the IR regime when $\\Lambda$ dominates the expansion of the Universe.
How does pressure gravitate? Cosmological constant problem confronts observational cosmology
Narimani, Ali; Scott, Douglas; Afshordi, Niayesh E-mail: nafshordi@pitp.ca
2014-08-01
An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 ? level. However, including higher resolution CMB observations (''highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 ? level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ?{sub 4} = 0.105 ± 0.049 (+highL CMB), or ?{sub 4} = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ?CDM including tensors, with 0?{sub 4}=), and also among different data sets.
Nizkorodov, Sergey
# First name Last name Status Affiliation Poster? Stay after? Veg? Transport 1 Laxmi Ramya Addala PhD California State University, Fresno No Don't Know No not sure 2 Lars Ahlm Postdoc University of California, San Diego Yes Don't Know No carpool 3 Sukon Aimanant PhD University of California, Riverside Yes
Broader source: Energy.gov [DOE]
The following provides greater detail regarding the types of reuse pursued for LM sites. It should be noted that many actual reuses combine several types of the uses listed below.
Marcus Hutter -1 -Bayesian Regression of Piecewise Constant Functions Bayesian Regression of
Hutter, Marcus
Marcus Hutter - 1 - Bayesian Regression of Piecewise Constant Functions Bayesian Regression6 June 2006 #12;Marcus Hutter - 2 - Bayesian Regression of Piecewise Constant Functions Table of Contents · Bayesian Regression · Quantities of Interest · Efficient Solutions by Dynamic Programming · Determination
Design of large time constant switched-capacitor filters for biomedical applications
Tumati, Sanjay
2005-02-17
This thesis investigates the various techniques to achieve large time constants and the ultimate limitations therein. A novel circuit technique for the realization of large time constants for high pass corners in switched-capacitor filters is also...
G. L. Klimchitskaya; V. M. Mostepanenko
2015-04-09
We obtain improved constraints on the coupling constants of axion-like particles to nucleons from a recently performed Casimir-less experiment. For this purpose, the differential force between a Au-coated sphere and either Au or Si sectors of a rotating disc, arising due to two-axion exchange, is calculated. Over a wide region of axion masses from 1.7 meV to 0.9 eV the obtained constraints are stronger up to a factor of 60 than the previously known ones following from the Cavendish-type experiment and measurements of the effective Casimir pressure.
Klimchitskaya, G L
2015-01-01
We obtain stronger constraints on the coupling constants of axion-like particles to nucleons from a recently performed Casimir-less experiment. For this purpose, the differential force between a Au-coated sphe\\-re and either Au or Si sectors of a rotating disc, arising due to two-axion exchange, is calculated. Over a wide region of axion masses from 1.7 meV to 0.9 eV the obtained constraints are stronger up to a factor of 60 than the previously known ones following from the Cavendish-type experiment and measurements of the effective Casimir pressure.
Estimation of the optical constants and the thickness of thin lms using unconstrained
Martínez, José Mario
Estimation of the optical constants and the thickness of thin #12;lms using unconstrained, spectral gradient method, optical constants, thin #12;lms. 1 #12; Proposed running head: Estimation of optical constants of thin #12;lms using SGM Corresponding author: Jos#19;e Mario Mart#19;#16;nez
FOURTH-ORDER ELASTIC CONSTANTS: GENERAL METHOD FOR DETERMINATION AND APPLICATIONS X. Markenscoff
Paris-Sud XI, Université de
FOURTH-ORDER ELASTIC CONSTANTS: GENERAL METHOD FOR DETERMINATION AND APPLICATIONS X. Markenscoff.- A list of the independent fourth-order elastic constants (FOEC's) and the interpenden- cies among the non. The fourth-order elastic constants are related to the second-derivatives of the wave velocity with respect
Paris-Sud XI, Université de
New Variation of Constants Formula for Some Partial Functional Differential Equations with Infinite, Morocco ezzinbi@ucam.ac.ma Abstract In this work, we give a new variation of constants formula for some words and phrases: Hille-Yosida operator, integral solutions, variation of constants formula, uniform
Physics 250 -Measurements of the Fine Structure Constant Derek Kimball January 2000 1
Budker, Dmitry
Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 1 #12;Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 2 #12;Physics 250 - Measurements of the Fine Structure Constant Derek Kimball January 2000 3 #12;Physics 250 - Measurements
SAMPLE-PATH ANALYSIS OF THE PROPORTIONAL RELATION AND ITS CONSTANT FOR DISCRETE-TIME
Ishizaki, Fumio
SAMPLE-PATH ANALYSIS OF THE PROPORTIONAL RELATION AND ITS CONSTANT FOR DISCRETE-TIME SINGLE and c is a constant which is called proportional constant. We call such a relation the proportional relation. It has been shown that similar proportional relations also hold for some other queueing systems
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics
Takada, Shoji
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics Kengo,Myodaiji, Okazaki 444. Japan (Received 28 September 1993; accepted 8 December 1993) The constant centrifugal of such practically useful approxima- tions the constant centrifugal potential approximation (CCPA) (or the energy
On the nature of rapidly fading Type II supernovae
Moriya, Takashi J; Ergon, Mattias; Blinnikov, Sergei I
2015-01-01
It has been suggested that Type II supernovae with rapidly fading light curves (a.k.a. Type IIL supernovae) are explosions of progenitors with low-mass hydrogen-rich envelopes which are of the order of 1 Msun. We investigate light-curve properties of supernovae from such progenitors. We confirm that such progenitors lead to rapidly fading Type II supernovae. We find that the luminosity of supernovae from such progenitors with the canonical explosion energy of 1e51 erg and 56Ni mass of 0.05 Msun can increase temporarily shortly before all the hydrogen in the envelope recombines. As a result, a bump appears in their light curves. The bump appears because the heating from the nuclear decay of 56Ni can keep the bottom of hydrogen-rich layers in the ejecta ionized, and thus the photosphere can stay there for a while. We find that the light-curve bump becomes less significant when we make explosion energy larger (>~ 2e51 erg), 56Ni mass smaller (<~ 0.01 Msun), 56Ni mixed in the ejecta, or the progenitor radius l...
Toward a sub-ppm measurement of the Fermi constant
David M. Webber
2010-06-21
The Fermi constant, G_F, describes the strength of the weak force and is determined most precisely from the mean life of the positive muon, tau_mu. Advances in theory have reduced the theoretical uncertainty on G_F as calculated from tau_mu to a few tenths of a part per million (ppm). The remaining uncertainty on G_F is entirely experimental, and is dominated by the uncertainty on tau_mu. The MuLan experiment is designed to measure the muon lifetime to part-per-million precision, a better-than twenty-fold improvement over the previous generation of experiments. In 2007, we reported an intermediate result, tau_mu=2.197013(24) microseconds (11 ppm), which is in excellent agreement with the previous world average. This mean life was measured using a pulsed surface muon beam stopped in a ferromagnetic target, surrounded by a symmetric scintillator detector array. Since this intermediate measurement, the detector was instrumented with waveform digitizers, the muon beam rate and beam extinction were increased, and two data sets were acquired on different targets, each containing over 10^12 muon decays. These data will lead to a new determination of G_F to better than a part per million.
Varying fine structure 'constant' and charged black holes
Bekenstein, Jacob D.; Schiffer, Marcelo
2009-12-15
Speculation that the fine-structure constant {alpha} varies in spacetime has a long history. We derive, in 4-D general relativity and in isotropic coordinates, the solution for a charged spherical black hole according to the framework for dynamical {alpha} J. D. Bekenstein, Phys. Rev. D 25, 1527 (1982).. This solution coincides with a previously known one-parameter extension of the dilatonic black hole family. Among the notable properties of varying-{alpha} charged black holes are adherence to a 'no hair' principle, the absence of the inner (Cauchy) horizon of the Reissner-Nordstroem black holes, the nonexistence of precisely extremal black holes, and the appearance of naked singularities in an analytic extension of the relevant metric. The exteriors of almost extremal electrically (magnetically) charged black holes have simple structures which makes their influence on applied magnetic (electric) fields transparent. We rederive the thermodynamic functions of the modified black holes; the otherwise difficult calculation of the electric potential is done by a shortcut. We confirm that variability of {alpha} in the wake of expansion of the universe does not threaten the generalized second law.
NIHAO III: The constant disc gas mass conspiracy
Stinson, G S; Wang, L; Macciò, A V; Herpich, J; Bradford, J D; Quinn, T R; Wadsley, J; Keller, B
2015-01-01
We show that the cool gas masses of galactic discs reach a steady state that lasts many Gyr after their last major merger in cosmological hydrodynamic simulations. The mass of disc gas, M$_{\\rm gas}$, depends upon a galaxy halo's spin and virial mass, but not upon stellar feedback. Halos with low spin have high star formation efficiency and lower disc gas mass. Similarly, lower stellar feedback leads to more star formation so the gas mass ends up nearly the same irregardless of stellar feedback strength. Even considering spin, the M$_{\\rm gas}$ relation with halo mass, M$_{200}$ only shows a factor of 3 scatter. The M$_{\\rm gas}$--M$_{200}$ relation show a break at M$_{200}$=$2\\times10^{11}$ M$_\\odot$ that corresponds to an observed break in the M$_{\\rm gas}$--M$_\\star$ relation. The constant disc mass stems from a shared halo gas density profile in all the simulated galaxies. In their outer regions, the profiles are isothermal. Where the profile rises above $n=10^{-3}$ cm$^{-3}$, the gas readily cools and th...
TYPES OF NONIMMIGRANT VISAS Type Description
for pleasure and cannot receive any type of payments. C-1*, Aliens in travel status while travelling directly through the C-2*, United States. C-3* D-1 Alien crewman on shore leave or transferring to another vessel is grounds for deportation. E-1 Aliens who conduct trade or inventories between the United States
A Constant Spectral Index for Sagittarius A* During Infrared/X-ray Intensity Variations
S. D. Hornstein; K. Matthews; A. M. Ghez; J. R. Lu; M. Morris; E. E. Becklin; M. Rafelski; F. K. Baganoff
2007-06-12
We report the first time-series of broadband infrared (IR) color measurements of Sgr A*, the variable emission source associated with the supermassive black hole at the Galactic Center. Using the laser and natural guide star AO systems on the Keck II telescope, we imaged Sgr A* in multiple near-infrared broadband filters with a typical cycle time of ~3 min during 4 observing runs (2005-2006), two of which were simultaneous with Chandra X-ray measurements. In spite of the large range of dereddened flux densities for Sgr A* (2-30 mJy), all of our near-IR measurements are consistent with a constant spectral index of alpha = -0.6+-0.2. Furthermore, this value is consistent with the spectral indices observed at X-ray wavelengths during nearly all outbursts; which is consistent with the synchrotron self-Compton model for the production of the X-ray emission. During the coordinated observations, one IR outburst occurs 1 GeV is generated, and it is this high-energy tail that gives rise to the X-ray outbursts. One possible explanation for this type of variation is from the turbulence induced by a magnetorotational instability, in which the outer scale length of the turbulence varies and changes the high-energy cutoff.
Mavromatos, Nick E
2015-01-01
On the occasion of a century from the proposal of General relativity by Einstein, I attempt to tackle some open issues in modern cosmology, via a toy but non-trivial model. Specifically, I would like to link together: (i) the smallness of the cosmological constant today, (ii) the evolution of the universe from an inflationary era after the big-bang till now, and (iii) local supersymmetry in the gravitational sector (supergravity) with a broken spectrum at early eras, by making use of the concept of the "running vacuum" in the context of a simple toy model of four-dimensional N=1 supergravity. The model is characterised by dynamically broken local supersymmetry, induced by the formation of gravitino condensates in the early universe. As I will argue, there is a Starobinsky-type inflationary era characterising the broken supersymmetry phase in this model, which is compatible with the current cosmological data, provided a given constraint is satisfied among some tree-level parameters of the model and the renorma...
Elastic Constants of Ni-Mn-Ga Magnetic Shape Memory Alloys
Stipcich, M. [Universitat de Barcelona; Manosa, L. [Universitat de Barcelona; Planes, A. [Universitat de Barcelona; Morin, M. [INSA de Lyon; Zarestky, Jerel L [ORNL; Lograsso, Tom [Ames Laboratory; Stassis, C. [Ames Laboratory
2004-01-01
We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in any of the elastic constants has been observed at the Curie point. The temperature dependence of the shear elastic constant C' has been found to be very different for the two alloys. Such a different behavior is in agreement with recent theoretical predictions for systems undergoing multi-stage structural transitions.
Layered Copper-Based Electrode for High-Dielectric Constant Oxide...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Copper-Based Electrode for High-Dielectric Constant Oxide Thin-Film-Based Devices Technology available for licenisng: A multilayer thin-film device containing copper layers...
Flanagan, C
2006-01-01
O’Callahan and J. -D. Choi. Hybrid dynamic data race detec-subtyping is sound, the hybrid compilation algorithmHybrid Type Checking Cormac Flanagan Department of Computer
Mitroi, F C
2011-01-01
The aim of this paper is to present some new Fejer-type results for convex functions. Improvements of Young's inequality (the arithmetic-geometric mean inequality) and other applications to special means are pointed as well.
Performance of W4 theory for spectroscopic constants and electrical properties of small molecules
Martin, Jan M.L.
Performance of W4 theory for spectroscopic constants and electrical properties of small molecules Accurate spectroscopic constants and electrical properties of small molecules are determined by means of W4 and post-W4 theories. For a set of 28 first- and second-row diatomic molecules for which very accurate
Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy
Dynamics of kinematically constrained bimolecular reactions having constant product recoil energy reactions in which the product recoil energy is assumed constant (CPR approximation). It is further assumed-shaped, peaking at the vibrational level with an energy equal to the reaction exoergicity minus the product recoil
Direct Test of the Time-Independence of Fundamental Nuclear Constants Using the Oklo
Shlyakhter, Ilya
Direct Test of the Time-Independence of Fundamental Nuclear Constants Using the Oklo Natural Reactor #3; Alexander I. Shlyakhter November 18, 1982 1 Introduction The following eight quantities enter the important natural constants of cosmology and atomic theory are connected by simple mathematical relations
THE PROBABILITIES OF ABSOLUTE RUIN IN THE RENEWAL RISK MODEL WITH CONSTANT FORCE OF INTEREST
Tang, Qihe
THE PROBABILITIES OF ABSOLUTE RUIN IN THE RENEWAL RISK MODEL WITH CONSTANT FORCE OF INTEREST of ...nite- and in...nite-time absolute ruin in the renewal risk model with constant premium rate; Convolution equiva- lence; Heavy tails; Renewal risk model 1. Introduction In this paper we address
Statistics of Landscapes Based on Free Energies, Replication and Degradation Rate Constants of
Stadler, Peter F.
Statistics of Landscapes Based on Free Energies, Replication and Degradation Rate Constants of RNA are computed from primary sequences by means of a folding algorithm which uses a minimum free energy criterion. Free energies as well as replication and degradation rate constants are derived from secondary
A piecewise-constant congestion taxing policy for repeated routing games q,qq
Johansson, Karl Henrik
on the flow of the vehicles on each road prior to the beginning of the taxing window (and, henceA piecewise-constant congestion taxing policy for repeated routing games q,qq Farhad Farokhi a-constant congestion tax- ing in which a central planner sets and announces the congestion taxes for fixed windows
Sezgin, Metin
2006-01-01
in the binary expansions of Feigenbaum constants a and d for the logistic map. The analysis is carried out constants; Normal numbers; Random number generation; Statistical analysis In a recent article Karamanos their conclusions. For example in the first table the calculated w2 value is 1.421 as stated. But this value fails
Evolution of the coupling constant in SU(2) lattice gauge theory with two adjoint fermions
Ari J. Hietanen; Kari Rummukainen; Kimmo Tuominen
2009-11-24
We measure the evolution of the coupling constant using the Schroedinger functional method in the lattice formulation of SU(2) gauge theory with two massless Dirac fermions in the adjoint representation. We observe strong evidence for an infrared fixed point, where the theory becomes conformal. We measure the continuum beta-function and the coupling constant as a function of the energy scale.
Constant Time Queries for Energy Efficient Paths in Multi-Hop Wireless Networks
Matijevic, Domagoj
Constant Time Queries for Energy Efficient Paths in Multi-Hop Wireless Networks Stefan Funke stations in such a way that approximately energy optimal paths can be retrieved in constant time, i. Keywords: Ad-Hoc and Sensor Networks, Routing, Power Control, Wireless LANs I. INTRODUCTION Ad hoc radio
Truong, Thanh N.
of a focusing technique to minimize the number of electronic structure calculations, while still preservingA direct ab inifio dynamics approach for calculating thermal rate constants using variational dynamics, " for calculations of thermal rate constants and related properties from first principles
Securing Circuits Against Constant-Rate Tampering Dana Dachman-Soled and Yael Tauman Kalai
International Association for Cryptologic Research (IACR)
Securing Circuits Against Constant-Rate Tampering Dana Dachman-Soled and Yael Tauman Kalai that remains secure even if a constant fraction of its wires are tampered with. Following the seminal work that such adversaries, who continuously tamper with the circuit, can learn at most logarithmically many bits of secret
DETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME
Hart, Gus
deposition and characterization of reactively-sputtered uranium nitride thin films. I also report opticalDETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME ULTRAVIOLET (1.6-35 NM.1 Application 1 1.2 Optical Constants 2 1.3 Project Focus 7 2 Uranium Nitride Thin Films 8 2.1 Sputtering 8 2
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
in the bulk of chargestabilized colloidal suspensions when electrohydrodynamic forces due to constant appliedHierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier used [1, 2] to study interfacial col loidal electrokinetic phenomena. An aqueous suspension
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
in the bulk of charge-stabilized colloidal suspensions when electrohydrodynamic forces due to constant appliedHierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier used [1, 2] to study interfacial col- loidal electrokinetic phenomena. An aqueous suspension
Melting in an Enclosure with Discrete Heating at a Constant Rate
Zhang, Yuwen
- Melting in an Enclosure with Discrete Heating at a Constant Rate Yuwen Zhang Zhongqi Chen Qijie · The melting of n-octadecane that is discretely heated at a constant rate from one side of an enclosure- Experimental Thermal and Fluid Science 1993; 6:196-201 rate heating mode of the melting process
Slow convergence of the BEM with constant elements in solving beam bending problems
Liu, Yijun
beam bending problems. This paper presents some BEM results with large-scale 2D models of simple beamSlow convergence of the BEM with constant elements in solving beam bending problems Y.J. Liu n , Y online 13 November 2013 Keywords: Boundary element method Constant element Beam bending problem a b s t r
Skeel, Robert
integral method, instead of solving the equivalent partial differential equation by a discretization method Constant Calculation Gang Zou* and Robert D. Skeely *Renaissance Technologies, East Setauket, New York ABSTRACT A reaction probability is required to calculate the rate constant of a diffusion
THE PROPORTIONALITY CONSTANT FOR THE SIMPLICIAL VOLUME OF LOCALLY SYMMETRIC SPACES
Bucher-Karlsson, Michelle
THE PROPORTIONALITY CONSTANT FOR THE SIMPLICIAL VOLUME OF LOCALLY SYMMETRIC SPACES MICHELLE BUCHER-KARLSSON Abstract. We follow ideas going back to Gromov's seminal article [Gr82] to show that the proportionality of G. The proportionality constant thus becomes easier to com- pute. Furthermore, this method also
An accurate determination of the Avogadro constant by counting the atoms in a 28Si crystal
Andreas, B; Bartl, G; Becker, P; Bettin, H; Borys, M; Busch, I; Gray, M; Fuchs, P; Fujii, K; Fujimoto, H; Kessler, E; Krumrey, M; Kuetgens, U; Kuramoto, N; Mana, G; Manson, P; Massa, E; Mizushima, S; Nicolaus, A; Picard, A; Pramann, A; Rienitz, O; Schiel, D; Valkiers, S; Waseda, A
2010-01-01
The Avogadro constant links the atomic and the macroscopic properties of matter. Since the molar Planck constant is well known via the measurement of the Rydberg constant, it is also closely related to the Planck constant. In addition, its accurate determination is of paramount importance for a definition of the kilogram in terms of a fundamental constant. We describe a new approach for its determination by "counting" the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope. It enabled isotope dilution mass spectroscopy to determine the molar mass of the silicon crystal with unprecedented accuracy. The value obtained, 6.02214084(18) x 10^23 mol^-1, is the most accurate input datum for a new definition of the kilogram.
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-Inspired SolarAbout /Two Electron Holes in HematiteType Ia Supernovae Type Ia
National Nuclear Security Administration (NNSA)
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 of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReporteeo | National Nucleara min [Type the abstract of theType
Crenshaw, Michael
to nuclear fusion. · Novae radiate primarily in the UV to X-ray region. · Types: Classical Novae: only one is hot enough for explosive fusion. For classical novae, this happens on a time scale of 103 105 years. · Thermonuclear runaway (TNR): capture of protons by heavy elements (CNO cycle), happens in seconds #12;5 Novae
Katsuda, Satoru [RIKEN (The Institute of Physical and Chemical Research) Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nozawa, Takaya [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Pooley, David [Department of Physics, Sam Houston State University, Huntsville, TX 77341-2267 (United States); Immler, Stefan [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 2077 (United States)
2014-01-10
We report on the X-ray spectral evolution of the nearby Type IIn supernova (SN) 2005ip based on Chandra and Swift observations covering ?1-6 yr after explosion. X-ray spectra in all epochs are well fitted by a thermal emission model with kT ? 7 keV. The somewhat high temperature suggests that the X-ray emission mainly arises from the circumstellar medium (CSM) heated by the forward shock. We find that the spectra taken two to three years after the explosion are heavily absorbed (N {sub H} ? 5 × 10{sup 22} cm{sup –2}), but the absorption gradually decreases to the level of the Galactic absorption (N {sub H} ? 4 × 10{sup 20} cm{sup –2}) at the final epoch. This indicates that the SN went off in a dense CSM and that the forward shock has overtaken it. The intrinsic X-ray luminosity stays constant until the final epoch, when it drops by a factor of ?2. The intrinsic 0.2-10 keV luminosity during the plateau phase is measured to be ?1.5 × 10{sup 41} erg s{sup –1}, ranking SN 2005ip as one of the brightest X-ray SNe. Based on the column density, we derive a lower limit of a mass-loss rate to be M-dot ?1.5×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, which roughly agrees with that inferred from the X-ray luminosity, M-dot ?2×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, where V{sub w} is the circumstellar wind speed. Such a high mass-loss rate suggests that the progenitor star had eruptive mass ejections similar to a luminous blue variable star. The total mass ejected in the eruptive period is estimated to be ?15 M {sub ?}, indicating that the progenitor mass is ? 25 M {sub ?}.
Broader source: Energy.gov [DOE]
Learn about the standard page types available in the Energy.gov Drupal content management system. For information about other available page types, or to request a new kind of page type, contact...
Practical pluggable types for Java
Papi, Matthew M
2008-01-01
This paper introduces the Checker Framework, which supports adding pluggable type systems to the Java language in a backward-compatible way. A type system designer defines type qualifiers and their semantics, and a compiler ...
Window Types | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
aluminum or vinyl cladding reduces maintenance requirements. Types of Window Glazing or Glass In addition to choosing a frame type, you will need to consider what type of glazing...
Decay constants of the pion and its excitations on the lattice.
Mastropas, Ekaterina V. [William and Mary College, JLAB; Richards, David G. [JLAB
2014-07-01
We present a calculation using lattice QCD of the ratios of decay constants of the excited states of the pion, to that of the pion ground state, at three values of the pion mass between 400 and 700 MeV, using an anisotropic clover fermion action with three flavors of quarks. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass. The strong suppression of the decay constant of the second excited state is consistent with its interpretation as a predominantly hybrid state.
Wave functions and decay constants of $B$ and $D$ mesons in the relativistic potential model
Mao-Zhi Yang
2012-01-30
With the decay constants of $D$ and $D_s$ mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in $B$ and $D$ mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of $B$ and $D$ mesons are obtained. Both the masses and decay constants obtained here can be consistent with the experimental data. The wave functions can be used in the study of $B$ and $D$ meson decays.
Leptonic B- and D-meson decay constants with 2+1 flavors of asqtad fermions
Andreas S. Kronfeld; Ethan T. Neil; James N. Simone; Ruth S. Van de Water; for the Fermilab Lattice Collaboration; for the MILC Collaboration
2015-01-08
We present the status of our updated D- and B-meson decay-constant analysis, based on the MILC $N_f = 2+1$ asqtad gauge ensembles. Heavy quarks are incorporated using the Wilson clover action with the Fermilab interpretation. This analysis includes ensembles at five lattice spacings from a $\\approx$ 0.045 to 0.15 fm, and light sea-quark masses down to 1/20th of the strange-quark mass. Projected error budgets for ratios of decay constants, in particular between bottom- and charm-meson decay constants, are presented.
B and D meson decay constants from 2+1 flavor improved staggered simulations
E. T. Neil; Jon A. Bailey; A. Bazavov; C. Bernard; C. M. Bouchard; C. DeTar; M. Di Pierro; A. X. El-Khadra; R. T. Evans; E. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; R. Jain; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; for the Fermilab Lattice Collaboration; for the MILC Collaboration
2011-12-16
We give an update on simulation results for the decay constants f_B, f_{B_s}, f_D and f_{D_s}. These decay constants are important for precision tests of the standard model, in particular entering as inputs to the global CKM unitarity triangle fit. The results presented here make use of the MILC (2+1)-flavor asqtad ensembles, with heavy quarks incorporated using the clover action with the Fermilab method. Partially quenched, staggered chiral perturbation theory is used to extract the decay constants at the physical point. In addition, we give error projections for a new analysis in progress, based on an extended data set.
Towards a consistent estimate of the chiral low-energy constants
V. Cirigliano; G. Ecker; M. Eidemuller; R. Kaiser; A. Pich; J. Portoles
2006-07-17
Guided by the large-Nc limit of QCD, we construct the most general chiral resonance Lagrangian that can generate chiral low-energy constants up to O(p^6). By integrating out the resonance fields, the low-energy constants are parametrized in terms of resonance masses and couplings. Information on those couplings and on the low-energy constants can be extracted by analysing QCD Green functions of currents both for large and small momenta. The chiral resonance theory generates Green functions that interpolate between QCD and chiral perturbation theory. As specific examples we consider the VAP and SPP Green functions.
Dust around Type Ia supernovae
Wang, Lifan
2005-01-01
Dust around Type Ia supernovae Lifan Wang 1,2 LawrenceIa. Subject headings: Supernovae: General, Dust, Extinctionline) bands for Type Ia supernovae. (a), upper panel, shows
Three-dimensional metrics as deformations of a constant curvature metric
B. Coll; J. Llosa; D. Soler
2001-04-23
Any three-dimensional Riemannian metric can be locally obtained by deforming a constant curvature metric along one direction. The general interest of this result, both in geometry and physics, and related open problems are stressed.
UAV PATH FOLLOWING FOR CONSTANT LINE-OF-SIGHT Rolf Rysdyk,
UAV PATH FOLLOWING FOR CONSTANT LINE-OF-SIGHT Rolf Rysdyk, University of Washington, Seattle, WA to a method to model `helmsman behavior'. The UAV control problem typically involves: air- speed, aerodynamic
Ferraro, R. J.; Osborne, R.; Stephens, R.
2000-01-01
, Sizing Constant Voltage Transformers to Maximize Voltage Regulationfor Process Control Devices. 4. EPRl PEAC, 1997, PQTN Application Brochure #Io-Tutorial; Inrush Current Measurement 5. Basic Measuring Instruments, Inc., Alex McEachern, power...
A constant-mass fuel delivery system for use in underwater autonomous vehicles
Saxton-Fox, Theresa Ann
2012-01-01
This thesis describes the design and assembly of two constant-mass fuel tanks to be used in autonomous underwater vehicles (AUVs). The fuel tanks are part of a power supply designed to increase AUV endurance without limiting ...
Research on Fuzzy Regulation Strategies in the Constant Air Volume Air Conditioning System
Bai, T.; Zhang, J.; Ning, N.; Tong, K.; Wu, Y.; Wang, H.
2006-01-01
The energy consumption of the constant air volume (CAV) system largely depends on the regulation strategies. Although some air conditioning systems are equipped with automatic regulation devices, others lack effective regulation strategies. To avoid...
Determination of Heat Capacities at Constant Volume from Experimental (P-Rho-T) Data
Tibaduiza Rincon, Andrea
2015-07-27
This work examines the uncertainty in the determination of the heat capacity at constant volume from experimental volumetric data. The proposed methodology uses the experimental (P-?-T) data for a ternary mixture of methane, ethane and propane...
On Possible Causes of Divergencies in Experimental Values of Gravitational Constant
A. L. Dmitriev
2006-10-31
It is shown that discrepancies in the experimental values of the gravitational constant might be caused by the temperature dependence of the gravitational force and inequality of the absolute temperatures of sample masses used in various gravitational experiments.
Sack, Jean H. (Jean Hope)
2013-01-01
The purpose of this thesis was to construct and seal air and containment tanks and other parts for a constant buoyancy power supply for an Autonomous Underwater Vehicle, or AUV. While multiple materials and techniques were ...
Universe Decay, Inflation and the Large Eigenvalue of the Cosmological Constant Seesaw
Michael McGuigan
2007-02-22
We discuss implications of the large eigenvalue of the cosmological constant seesaw mechanism extending hep-th/0602112 and hep-th/0604108. While the previous papers focused on the small eigenvalue as a cosmological constant associated with the accelerating Universe, here we draw attention to the physical implications of the large eigenvalue. In particular we find that the large eigenvalue can give rise to a period of inflation terminated by Universe decay. The mechanism involves quantum tunneling and mixing and introduces parameters $\\Gamma$, the decay constant, and $\\theta$, the mixing angle. We discuss the cosmological constant seesaw mechanism in the context of various models of current interest including chain inflation, inflatonless inflation, string theory, Universe entanglement and different approaches to the hierarchy problem.
On the distribution of estimators of diffusion constants for Brownian motion
Denis Boyer; David S. Dean
2011-07-26
We discuss the distribution of various estimators for extracting the diffusion constant of single Brownian trajectories obtained by fitting the squared displacement of the trajectory. The analysis of the problem can be framed in terms of quadratic functionals of Brownian motion that correspond to the Euclidean path integral for simple Harmonic oscillators with time dependent frequencies. Explicit analytical results are given for the distribution of the diffusion constant estimator in a number of cases and our results are confirmed by numerical simulations.
Optimal transport of two ions under slow spring-constant drifts
Xiao-Jing Lu; Mikel Palmero; Andreas Ruschhaupt; Xi Chen; Juan Gonzalo Muga
2015-02-05
We investigate the effect of slow spring-constant drifts of the trap used to shuttle two ions of different mass. We design transport protocols to suppress or mitigate the final excitation energy by applying invariant-based inverse engineering, perturbation theory, and a harmonic dynamical normal-mode approximation. A simple, explicit trigonometric protocol for the trap trajectory is found to be robust with respect to the spring-constant drifts.
Solution of the Schrödinger equation making use of time-dependent constants of motion
G. F. Torres del Castillo
2015-03-18
It is shown that if a complete set of mutually commuting operators is formed by constants of motion, then, up to a factor that only depends on the time, each common eigenfunction of such operators is a solution of the Schr\\"odinger equation. In particular, the operators representing the initial values of the Cartesian coordinates of a particle are constants of motion that commute with each other and from their common eigenfunction one readily obtains the Green function.
Constants of geodesic motion in higher-dimensional black-hole spacetimes
Krtous, Pavel [Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Kubiznak, David [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Page, Don N. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Vasudevan, Muraari [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); JLR Engineering, 111 SE Everett Mall Way, E-201, Everett, Washington 98208-3236 (United States)
2007-10-15
In [Phys. Rev. Lett. 98, 061102 (2007)], we announced the complete integrability of geodesic motion in the general higher-dimensional rotating black-hole spacetimes. In the present paper we prove all the necessary steps leading to this conclusion. In particular, we demonstrate the independence of the constants of motion and the fact that they Poisson commute. The relation to a different set of constants of motion constructed in [J. High Energy Phys. 02 (2007) 004] is also briefly discussed.
Millimet, Scott Alan
1982-01-01
THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKET NG SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Ma) or Subject: Agricultural Economics THE EXPORT RESPONSIVENESS OF THE ARGENTINE GRAIN EXPORT MARKETING SYSTEM: A CONSTANT MARKET SHARE ANALYSIS A Thesis by SCOTT ALAN MILLIMET Approved as to style...
Spinor Field with Polynomial Nonlinearity in LRS Bianchi type-I spacetime
Bijan Saha
2015-07-22
Within the scope of Bianchi type-I cosmological model the role of spinor field on the evolution of the Universe is investigated. In doing so we have considered a polynomial type of nonlinearity. It is found that depending on the sign of self-coupling constant the model allows either accelerated mode of expansion or oscillatory mode of evolution. Unlike general Bianchi type-I and Bianchi type $VI_0$ models in this case neither mass term nor the nonlinear term in the Lagrangian of spinor field vanish.
Withers, Paul
344 APPENDIX B GENERATING CONSTANT ALTITUDE DATA FROM THE PDS PROFILES Whilst analysing the MGS an interesting complication in how the constant altitude data are generated. Although this is not of direct. The constant altitude data in the PDS archive are generated from the profile data in the same archive (Keating
Pluggable type-checking for custom type qualifiers in Java
Papi, Matthew M.
2007-09-17
We have created a framework for adding custom type qualifiers to the Javalanguage in a backward-compatible way. The type system designer definesthe qualifiers and creates a compiler plug-in that enforces theirsemantics. ...
PICTURE GROUPS OF FINITE TYPE AND COHOMOLOGY IN TYPE An
Igusa, Kiyoshi
PICTURE GROUPS OF FINITE TYPE AND COHOMOLOGY IN TYPE An KIYOSHI IGUSA, KENT ORR, GORDANA TODOROV a picture group. We construct a finite CW complex which is shown in another paper [10] to be a K(, 1) for this picture group. In [5] another independent proof was given for this fact in the special case of type
Abstract Data Types 5 Algebraic Theory of Abstract Data Types
Berger, Ulrich
stack top: stack elts The following is an algebra for the signature STACK. Algebra SeqN Carriers N, N43 Part II Abstract Data Types #12;44 5 Algebraic Theory of Abstract Data Types An Abstract Data Type (ADT) is a collection of objects and functions, that is, an algebra, where one ignores how
Constant-intensity waves and their modulation instability in non-Hermitian potentials
Konstantinos G. Makris; Ziad H. Musslimani; Demetrios N. Christodoulides; Stefan Rotter
2015-03-31
In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole new class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study, for the first time, the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.
Direct Test of the Time-Independence of Fundamental Nuclear Constants Using the Oklo Natural Reactor
Alexander I. Shlyakhter
2003-08-06
[NOTE: This 1983 preprint is being uploaded to arXiv.org after the death of its author, who supported online distribution of his work. Contact info of the submitter is at http://ilya.cc .] The positions of neutron resonances have been shown to be highly sensitive to the variation of fundamental nuclear constants. The analysis of the measured isotopic shifts in the natural fossil reactor at Oklo gives the following restrictions on the possible rates of the interaction constants variation: strong ~2x10^-19 yr^-1, electromagnetic ~5x10^-18 yr^-1, weak ~10^-12 yr^-1. These limits permit to exclude all the versions of nuclear constants contemporary variation discussed in the literature. URL: http://alexonline.info >. For more recent analyses see hep-ph/9606486, hep-ph/0205206 and astro-ph/0204069 .
Room-temperature elastic constants of Sc and ScD[sub 0. 18
Leisure, R.G. ); Schwarz, R.B.; Migliori, A.; Lei, M. )
1993-07-01
The complete set of elastic constants for Sc and ScD[sub 0.18] has been measured at room temperature. The results show that the addition of hydrogen to this rare-earth metal has a qualitatively different effect than the addition of hydrogen to transition metals such as palladium, vanadium, niobium, and tantalum. In the case of Sc all five elastic constants increase with the addition of hydrogen. The bulk modulus for ScD[sub 0.18] is 9.5% higher than that for Sc. The Debye temperature computed from the room-temperature elastic constants is 355 K for Sc and 371 K for ScD[sub 0.18].
Type Ia Supernova Progenitors, Environmental Effects, and Cosmic Supernova Rates
Ken'ichi Nomoto; Hideyuki Umeda; Izumi Hachisu; Mariko Kato; Chiaki Kobayashi; Takuji Tsujimoto
1999-07-27
Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting white dwarfs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction $X$(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependence of SNe Ia brighness on the galaxy types. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies.
Hsu, Cheng-Ting (Ames, IA)
1984-01-01
A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.
Annotated Type Systems Program Analysis
Palsberg, Jens
Danish Summary xi 1 Introduction 1 1.1 The Standard Type System . . . . . . . . . . . . . . . . . 3 1 . . . . . . . . . . . . . . . . . . 36 2.1.3 The Conjunction Type System . . . . . . . . . . . . 37 2.2 The Power of tAnnotated Type Systems for Program Analysis Kirsten Lackner Solberg Computer Science Department
PROGRAMMING WITH TYPES A Dissertation
Weirich, Stephanie
WITH TYPES Stephanie Claudene Weirich, Ph.D. Cornell University 2002 Run-time type analysis, facilities to support type analysis often require complicated language semantics that allow little freedom to list. Steve's parents Arthur and Deborah Zdancewic have encouraged me as long as I have known them. I
On the Verdet constant and Faraday rotation for graphene-like materials
Mikkel H. Brynildsen; Horia D. Cornean
2013-02-21
We present a rigorous and rather self-contained analysis of the Verdet constant in graphene- like materials. We apply the gauge-invariant magnetic perturbation theory to a nearest- neighbour tight-binding model and obtain a relatively simple and exactly computable formula for the Verdet constant, at all temperatures and all frequencies of sufficiently large absolute value. Moreover, for the standard nearest neighbour tight-binding model of graphene we show that the transverse component of the conductivity tensor has an asymptotic Taylor expansion in the external magnetic field where all the coefficients of even powers are zero.
Information content in $F(R)$ brane models with non-constant curvature
Correa, R A C; Dutra, A de Souza; da Rocha, Roldao; Menezes, R
2015-01-01
In this work we investigate the entropic information-measure in the context of braneworlds with non-constant curvature. The braneworld entropic information is studied for gravity modified by the squared of the Ricci scalar, besides the usual Einstein-Hilbert term. We showed that the minimum value of the brane configurational entropy provides a stricter bound on the parameter that is responsible for the $F(R)$ model to differ from the Einstein-Hilbert standard one. Our results are moreover consistent to a negative bulk cosmological constant.
Lattice study of the leptonic decay constant of the pion and its excitations
Mastropas, Ekaterina; Richard, David
2014-11-01
We present a calculation of the decay constant of the pion, and its lowest-lying three excitations, at three values of the pion mass between around 400 and 700 MeV, using anisotropic clover lattices. We use the variational method to determine an optimal interpolating operator for each of the states. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass.
Particle trajectories beneath small amplitude shallow water waves in constant vorticity flows
Delia Ionescu-Kruse
2011-06-20
We investigate the particle trajectories in a constant vorticity shallow water flow over a flat bed as periodic waves propagate on the water's free surface. Within the framework of small amplitude waves, we find the solutions of the nonlinear differential equations system which describes the particle motion in the considered case, and we describe the possible particle trajectories. Depending on the relation between the initial data and the constant vorticity, some particle trajectories are undulating curves to the right, or to the left, others are loops with forward drift, or with backward drift, others can follow some peculiar shapes.
Geometric Thermodynamics of Kerr-AdS black hole with a Cosmological Constant as State Variable
Alexis Larranaga; Sindi Mojica
2012-04-17
The thermodynamics of the Kerr-AdS black hole is reformulated within the context of the formalism of geometrothermodynamics (GTD) and the cosmological constant is considered as a new thermodynamical parameter. We conclude that the mass of the black hole corresponds to the total enthalpy of this system. Choosing appropriately the metric in the equilibrium states manifold, we study the phase transitions as a divergence of the thermodynamical curvature scalar. This approach reproduces the Hawking-Page transition and shows that considering the cosmological constant as a thermodynamical parameter does not contribute with new phase transitions.
Electronic constant current and current pulse signal generator for nuclear instrumentation testing
Brown, R.A.
1994-04-19
Circuitry is described for testing the ability of an intermediate range nuclear instrument to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on. 1 figures.
Electronic constant current and current pulse signal generator for nuclear instrumentation testing
Brown, Roger A. (Amsterdam, NY)
1994-01-01
Circuitry for testing the ability of an intermediate range nuclear instrut to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on.
Singlet axial-vector coupling constant of the nucleon in QCD without instantons
Janardan P. Singh
2015-07-19
We have analyzed axial-vector current-current correlation functions between one-nucleon states to calculate the singlet axial-vector coupling constant of the nucleon. The octet-octet and the octet-singlet current correlators, investigated in this work, do not require any use of instanton effects. The QCD and hadronic parameters used for the evaluation of correlators have been varied by (10 - 20)%. The value of the singlet axial-vector coupling constant of the nucleon obtained from this analysis is consistent with its current determination from experiments and QCD theory.
SU(2) chiral fits to light pseudoscalar masses and decay constants
A. Bazavov; C. Bernard; C. DeTar; X. Du; W. Freeman; Steven Gottlieb; Urs M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. B. Oktay; J. Osborn; R. Sugar; D. Toussaint; R. S. Van de Water
2009-11-03
We present the results of fits to recent asqtad data in the light pseudoscalar sector using SU(2) partially-quenched staggered chiral perturbation theory. Superfine (a~0.06 fm) and ultrafine (a~0.045 fm) ensembles are used, where light sea quark masses and taste splittings are small compared to the strange quark mass. Our fits include continuum NNLO chiral logarithms and analytic terms. We give preliminary results for the pion decay constant, SU(2) low-energy constants and the chiral condensate in the two-flavor chiral limit.
Lomboy, Gilson [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, Iowa 50011 (United States); Sundararajan, Sriram, E-mail: srirams@iastate.edu [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States); Wang Kejin [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, Iowa 50011 (United States); Subramaniam, Shankar [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)
2011-11-15
A method for determining Hamaker constant of cementitious materials is presented. The method involved sample preparation, measurement of adhesion force between the tested material and a silicon nitride probe using atomic force microscopy in dry air and in water, and calculating the Hamaker constant using appropriate contact mechanics models. The work of adhesion and Hamaker constant were computed from the pull-off forces using the Johnson-Kendall-Roberts and Derjagin-Muller-Toropov models. Reference materials with known Hamaker constants (mica, silica, calcite) and commercially available cementitious materials (Portland cement (PC), ground granulated blast furnace slag (GGBFS)) were studied. The Hamaker constants of the reference materials obtained are consistent with those published by previous researchers. The results indicate that PC has a higher Hamaker constant than GGBFS. The Hamaker constant of PC in water is close to the previously predicted value C{sub 3}S, which is attributed to short hydration time ({<=} 45 min) used in this study.
Bianchi Type-I Universe with Wet Dark Fluid
T. Singh; R. Chaubey
2010-07-08
The Bianchi type-I universe filled with dark energy from a wet dark fluid has been considered. A new equation of state for the dark energy component of the universe has been used. It is modeled on the equation of state $p=\\gamma (\\rho -\\rho_\\star)$ which can describe a liquid, for example water. The exact solutions to the corresponding field equations are obtained in quadrature form. The solution for constant deceleration parameter have been studied in detail for power-law and exponential forms both. The cases $\\gamma =1$ and $\\gamma =0$ have been also analysed.
Marginal evidence for cosmic acceleration from Type Ia supernovae
Jeppe Trøst Nielsen; Alberto Guffanti; Subir Sarkar
2015-06-09
The "standard" model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these "standardisable candles" indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.
Marginal evidence for cosmic acceleration from Type Ia supernovae
Nielsen, Jeppe Trøst; Sarkar, Subir
2015-01-01
The `standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these `standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.
University of Alberta SafeType: Detecting Type Violations for Type-Based Alias
Amaral, José Nelson
University of Alberta SafeType: Detecting Type Violations for Type-Based Alias Analysis of C Edmonton, Alberta Permission is hereby granted to the University of Alberta Libraries to reproduce single, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other
Sivaramakrishnan, R.; Michael, J. V.; Chemical Sciences and Engineering Division
2009-04-30
High-temperature rate constant experiments on OH with the five large (C{sub 5}-C{sub 8}) saturated hydrocarbons n-heptane, 2,2,3,3-tetramethylbutane (2,2,3,3-TMB), n-pentane, n-hexane, and 2,3-dimethylbutane (2,3-DMB) were performed with the reflected-shock-tube technique using multipass absorption spectrometric detection of OH radicals at 308 nm. Single-point determinations at {approx}1200 K on n-heptane, 2,2,3,3-TMB, n-hexane, and 2,3-DMB were previously reported by Cohen and co-workers; however, the present work substantially extends the database to both lower and higher temperature. The present experiments span a wide temperature range, 789-1308 K, and represent the first direct measurements of rate constants at T > 800 K for n-pentane. The present work utilized 48 optical passes corresponding to a total path length of {approx}4.2 m. As a result of this increased path length, the high OH concentration detection sensitivity permitted pseudo-first-order analyses for unambiguously measuring rate constants. The experimental results can be expressed in Arrhenius form in units of cm{sup 3} molecule{sup -1} s{sup -1} as follows: K{sub OH+n-heptane} = (2.48 {+-} 0.17) x 10{sup -10} exp[(-1927 {+-} 69 K)/T] (838-1287 K); k{sub OH+2,2,3,3-TMB} = (8.26 {+-} 0.89) x 10{sup -11} exp[(-1337 {+-} 94 K)/T] (789-1061 K); K{sub OH+n-pentane} = (1.60 {+-} 0.25) x 10{sup -10} exp[(-1903 {+-} 146 K)/T] (823-1308 K); K{sub OH+n-hexane} = (2.79 {+-} 0.39) x 10{sup -10} exp[(-2301 {+-} 134 K)/T] (798-1299 K); and k{sub OH+2,3-DMB} = (1.27 {+-} 0.16) x 10{sup -10} exp[(-1617 {+-} 118 K)/T] (843-1292 K). The available experimental data, along with lower-T determinations, were used to obtain evaluations of the experimental rate constants over the temperature range from {approx}230 to 1300 K for most of the title reactions. These extended-temperature-range evaluations, given as three-parameter fits, are as follows: k{sub OH+n-heptane} = 2.059 x 10{sup -5}T{sup 1.401} exp(33 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (241-1287 K); k{sub OH+2,2,3,3-TMB} = 6.835 x 10{sup -17}T{sup 1.886} exp(-365 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (290-1180 K); k{sub OH+n-pentane} = 2.495 x 10{sup -16}T{sup 1.649} exp(80 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (224-1308 K); k{sub OH+n-hexane} = 3.959 x 10{sup -18}T{sup 2.218} exp(443 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (292-1299 K); and k{sub OH+2,3-DMB} = 2.287 x 10{sup -17}T{sup 1.958} exp(365 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (220-1292 K). The experimental data and the evaluations obtained for these five larger alkanes in the present work were used along with prior data/evaluations obtained in this laboratory for H abstractions by OH from a series of smaller alkanes (C{sub 3}?C{sub 5}) to devise rate rules for abstractions from various types of primary, secondary, and tertiary H atoms. Specifically, the current scheme was applied with good success to H abstractions by OH from a series of n-alkanes (n-octane through n-hexadecane). The total rate constants using this group scheme for reactions of OH with selected large alkanes are given as three-parameter fits in this article. The rate constants for the various abstraction channels in any large n-alkane can also be obtained using the groups listed in this article. The present group scheme serves to reduce the uncertainties in rate constants for OH + alkane reactions.
Optical constants of ice from the ultraviolet to the microwave: A revised compilation
Warren, Stephen
only in the far infrared. Tables of the revised optical constants are available on a website. Citation not be significant. (The revised compilation is available as tables at http and Price [2001] reviewed experimental results from several publica- tions and concluded that the absorption
Constant magnetic field and 2d non-commutative inverted oscillator
Stefano Bellucci
2003-01-28
We consider a two-dimensional non-commutative inverted oscillator in the presence of a constant magnetic field, coupled to the system in a ``symplectic'' and ``Poisson'' way. We show that it has a discrete energy spectrum for some value of the magnetic field.
Logistic Growth: Quadratic, No Time Delay, K Constant b = [K -N(0)]/N(0)
Caraco, Thomas
Logistic Growth: Quadratic, No Time Delay, K Constant #12;b = [K - N(0)]/N(0) Logistic Population-Cummings Protozoan, small metazoan & large mammal: Logistic growth (app.), Increasing time to max dN/dt #12;Gause, sociology, technology How might logistic growth's assumptions fail biologically? #12;Density
Optimum Control for Interior Permanent Magnet Synchronous Motors (IPMSM) in Constant
Noé, Reinhold
Optimum Control for Interior Permanent Magnet Synchronous Motors (IPMSM) in Constant Torque and Electrical Drives, Paderborn, Germany Abstract--Interior Permanent Magnet Synchronous Motors (IPMSM) gain-power speed area. A widespread electrical machine used for this purpose is the Interior Permanent Magnet
Can Cosmological Constant be a Forbidden Zone (GAP) in Quantum Vacuum
Vladan Pankovic; Rade Glavatovic; Simo Ciganovic
2008-04-15
In this work we suggest, without detailed mathematical analysis, a hypothesis on the physical meaning of cosmological constant. It is primarily based on a conceptual analogy with energy characteristics of the crystal lattice structure, i.e. energy zones theory in solid state physics. Namely, according to some theories (holographic principle, emergent gravity etc.) it is supposed that empty space, i.e. quantum vacuum holds a structure like to crystal lattice. It implies a possibility of the existence of totally occupied zones consisting of many levels of the negative energies as well as at least one negative energy forbidden zone, i.e. negative energy gap without any (occupied or empty) level of the negative energy. We suppose that given negative energy forbidden zone in the quantum vacuum represents effectively a positive energy zone without quantum particles that corresponds to cosmological constant. Also we suggest some other (less extravagant) model of the cosmological constant. Here cosmological constant is usually considered as the effect of the quantum vacuum fluctuations where problem of the cut-off can be solved quite simply since here integration over unlimited domain of the quasi-momentums must be changed by integration over one, finite "Brillouin zone".
Andres Gomberoff; Marc Henneaux; Claudio Teitelboim
2005-01-19
We study the decay of the cosmological constant in two spacetime dimensions through production of pairs. We show that the same nucleation process looks as quantum mechanical tunneling (instanton) to one Killing observer and as thermal activation (thermalon) to another. Thus, we find another striking example of the deep interplay between gravity, thermodynamics and quantum mechanics which becomes apparent in presence of horizons.
Brane gravity, massless bulk scalar, and self-tuning of the cosmological constant
Kim, Jihn E.; Kyae, Bumseok; Shafi, Qaisar
2004-09-15
We show that a self-tuning mechanism of the cosmological constant could work in 5D noncompact space-time with a Z{sub 2} symmetry in the presence of a massless scalar field. The standard model matter fields live only on the 4D brane. The change of vacuum energy on the brane (brane cosmological constant) by, for instance, electroweak and QCD phase transitions, just gives rise to dynamical shifts of the profiles of the background metric and the scalar field in the extra dimension, keeping 4D space-time flat without any fine-tuning. To avoid naked singularities in the bulk, the brane cosmological constant should be negative. We introduce an additional brane-localized 4D Einstein-Hilbert term so as to provide the observed 4D gravity with the noncompact extra dimension. With a general form of the brane-localized gravity term allowed by the symmetries, the low energy Einstein gravity is successfully reproduced on the brane at long distances. We show this phenomenon explicitly for the case of vanishing bulk cosmological constant.
Relating the Newman-Penrose constants to the Geroch-Hansen multipole moments
Thomas Bäckdahl
2009-08-25
In this paper, we express the Newman--Penrose constants in terms of the Geroch--Hansen multipole moments for stationary spacetimes. These expressions are translation-invariant combinations of the multipole moments up to quadrupole order, which do not normally vanish.
Changing boreal methane sources and constant biomass burning during the last termination
Chappellaz, Jérôme
LETTERS Changing boreal methane sources and constant biomass burning during the last termination. Stocker3 Past atmospheric methane concentrations show strong fluctua- tions in parallel to rapid glacial climate changes in the Northern Hemisphere1,2 superimposed on a glacialinterglacial doubling of methane
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS
Hauswirth, Laurent
THE GEOMETRY OF EMBEDDED CONSTANT MEAN CURVATURE TORI IN THE 3-SPHERE VIA INTEGRABLE SYSTEMS L Alexandrov embedded cylinders is explicitly determined. We prove that all embedded cmc tori in the 3-sphere are surfaces of revolution using a combination of integrable systems methods and geometric analysis techniques
Switching Lemma for Bilinear Tests and Constant-size NIZK Proofs for Linear Subspaces
International Association for Cryptologic Research (IACR)
Switching Lemma for Bilinear Tests and Constant-size NIZK Proofs for Linear Subspaces Charanjit S of America Sunnyvale, CA 94085, USA October 7, 2014 Abstract We state a switching lemma for tests on adversarial responses involving bilinear pairings in hard groups, where the tester can effectively switch
Miller, William H.
Path integral evaluation of the quantum instanton rate constant for proton transfer in a polar developed by Azzouz and Borgis. Monte Carlo path integral methods are used to carry out the calculations evaluated for comparison using the present path integral approach. A technique is then introduced
Determinationof Propagation Constants of TransmissionLines using 1-port TDR measurements
Swaminathan, Madhavan
transmission line was extracted from DC to 1OG& Simulation of the lossy transmission line using the extractedDeterminationof Propagation Constants of TransmissionLines using 1-port TDR measurements Woopoung of transmission lines were measured from 1-port TDR measurements. Since the TDR measurement is a 1-port
Evolving Lorentzian wormholes supported by phantom matter with constant state parameters
Mauricio Cataldo; Pedro Labrana; Sergio del Campo; Juan Crisostomo; Patricio Salgado
2008-10-15
In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made out of phantom energy. We show that this exotic source can support the existence of evolving wormhole spacetimes. Explicitly, a family of evolving Lorentzian wormholes conformally related to another family of zero-tidal force static wormhole geometries is found in Einstein gravity. Contrary to the standard wormhole approach, where first a convenient geometry is fixed and then the matter distribution is derived, we follow the conventional approach for finding solutions in theoretical cosmology. We derive an analytical evolving wormhole geometry by supposing that the radial tension (which is negative to the radial pressure) and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. At spatial infinity this evolving wormhole, supported by this anisotropic matter, is asymptotically flat, and its slices $t=$ constant are spaces of constant curvature. During its evolution the shape of the wormhole expands with constant velocity, i.e without acceleration or deceleration, since the scale factor has strictly a linear evolution.
Thermal Effects on PCB Laminate Material Dielectric Constant and Dissipation Scott Hinaga
Koledintseva, Marina Y.
@cisco.com Marina Y. Koledintseva, James L. Drewniak, Amendra Koul, Fan Zhou EMC Laboratory, Missouri University constant (Dk) and dissipation factor (Df) used in circuit design and signal integrity (SI) modeling product [1-7]. During the production process at the material maker's factory, these components are exposed
ur solid Earth undergoes constant change from motions within its core
McLeod, Dennis
O ur solid Earth undergoes constant change from motions within its core to the surface. Solid Earth is the physical planet we live on, not the oceans or atmosphere. Motions near Earth's cen- ter affect the geodynamo, which generates the Earth's magnetic field. Convection within Earth's mantle drives plate
FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO
Le Roy, Robert J.
FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO Edward G. Lee-resolution FTIR emission spectroscopy measurements for the five common isoto- pomers of GeO are combined9), photoelectron spectroscopy (10), electronic absorption (1113), and emission (14) spectroscopy, and in matrix
Evaluating the von Kármán Constant in Sediment-laden Air Flow
Li, Bailiang
2012-02-14
Shear velocity is a critical variable used in many hydrodynamic and aeolian applications. The Law of the Wall is commonly used to derive shear velocity as the product of the slope of a measured velocity profile and the von Kármán constant, ? = 0...
Scaling of classical rate constants on scaled potential-energy surfaces Myung Soo Kim,a)
Kim, Myung Soo
or dynamical calculation of a rate constant is to use data from electronic structure calculation. Structure at moderately high levels of electronic structure calculation. © 2001 American Institute of Physics. DOI: 10 state theories and the methods based on classical or quantal dynamics calculation.47 When
Bell, Alexis T.
As ab initio electronic structure calculations become more accurate, inherent sources of error, facilitate reactive flux calculations. As an example we compute the dynamically corrected rate constant on which the reaction occurs. A large number of electronic structure theo- ries are available
Mechanics Systems on Para-Kaehlerian Manifolds of Constant J-Sectional Curvature
Mehmet Tekkoyun
2009-02-20
The goal of this paper is to present Euler-Lagrange and Hamiltonian equations on R2n which is a model of para-Kaehlerian manifolds of constant J-sectional curvature. In conclusion, some differential geometrical and physical results on the related mechanic systems have been given.
Photon emission in a constant magnetic field in 2+1 dimensional space-time
J. T. S. Amaral; S. I. Zlatev
2005-11-01
We calculate by the proper-time method the amplitude of the two-photon emission by a charged fermion in a constant magnetic field in (2+1)-dimensional space-time. The relevant dynamics reduces to that of a supesymmetric quantum-mechanical system with one bosonic and one fermionic degrees of freedom.
Time Domain Reflectometry Surface Reflections for Dielectric Constant in Highly Conductive Soils
Nowack, Robert L.
Time Domain Reflectometry Surface Reflections for Dielectric Constant in Highly Conductive Soils reflectometry TDR mea- surement in highly conductive soils. It makes use of information contained in the TDR signal from the reflection at the surface of the soil rather than the reflection from the end
Reid, Scott A.
: Application to ozone formation Mikhail V. Ivanov and Dmitri Babikov Citation: J. Chem. Phys. 136, 184304 (2012 for computing thermal rate constant of recombination: Application to ozone formation Mikhail V. Ivanov of ozone. Comparison of the predicted rate vs. experimental result is presented. © 2012 American Institute
HF Multiresonant Electronic Ballast for Fluorescent Lamps with Constant Filament Preheat Voltage
HF Multiresonant Electronic Ballast for Fluorescent Lamps with Constant Filament Preheat Voltage resonance arrangement that acts as a current source. During warm up the filaments are driven by a secondary the filament and shorts out the voltage across the lamp. Simulation and experimental results suggest
effects al- ter the differential and, perhaps much more surpris- ingly, the integral cross sectionsVolume 203, number 56 CHEMICAL PHYSICSLETTERS 5 March 1993 Integral rate constant measurements'= 1,j') rotational distributions are presented; at this time no corresponding theoretical calculations
Sub-THz complex dielectric constants of smectite clay thin samples with Na$^{+}$/Ca$^{++}$-ions
Rezwanur Rahman; Douglas K. McCarty; Manika Prasad
2015-07-28
We implement a technique to characterize the electromagnetic properties at frequencies 100 to 165 GHz (3 cm$^{-1}$ to 4.95 cm$^{-1}$) of oriented smectite samples using an open cavity resonator connected to a sub-millimeter wave VNA (Vector Network Analyzer). We measured dielectric constants perpendicular to the bedding plane on oriented Na$^{+}$ and Ca$^{++}$-ion stabilized smectite samples deposited on a glass slide at ambient laboratory conditions (room temperature and room light). The clay layer is much thinner ($\\sim$ 30 $\\mu$m) than the glass substrate ($\\sim$ 2.18 mm). The real part of dielectric constant, $\\epsilon_{re}$, is essentially constant over this frequency range but is larger in Na$^{+}$- than in Ca$^{++}$-ion infused clay. The total electrical conductivity (associated with the imaginary part of dielectric constant, $\\epsilon_{im}$) of both samples increases monotonically at lower frequencies ($$ 110 GHz. The dispersion of the samples display a dependence on the ionic strength in the clay interlayers, i.e., $\\zeta$-potential in the Stern layers.
Measurements of the complex dielectric constant of volcanic ash from 4 to 19 GHz
Perger, Warren F.
Measurements of the complex dielectric constant of volcanic ash from 4 to 19 GHz R. J. Adams,1 W. F. Perger,2 W. I. Rose,3 and A. Kostinski4 Abstract Dielectric data in volcanic ash at weather radar wavelengths (centimeter range) are extremely sparse and are crucial for radar sensing of ash clouds
Allouche, Jean-Paul
Algebraic irrational binary numbers cannot be fixed points of nonÂtrivial constant length irrational number in a given base? A common conjectured answer to this vague question is that these digits . A widely believed conjecture is that an algebraic irrational number is a normal number in each base k â?? 2
Lombardi, John R.
Transition Metal Dimer Internuclear Distances from Measured Force Constants Joseph L. Jules distances, have been extended to the transition metal dimers to test which one gives the most accurate fit's and Guggenheimer's for the transition metal dimers. Although Pauling's rule gives the best results, the remarkable
Table A1 Molar mass, gas constant, and critical-point properties
Kostic, Milivoje M.
of carbon dioxide, CO2 Table A21 Ideal-gas properties of carbon monoxide, CO Table A22 Ideal Properties of the atmosphere at high altitude Table A17 Ideal-gas properties of air Table A18 Ideal-point properties Molar mass, constant, Temperature, Pressure, Volume, Substance Formula M kg/kmol R kJ/kg·K* K MPa
The rho meson decay constant using a tadpole-improved action
Randy Lewis; R. M. Woloshyn
1996-07-25
The rho meson decay constant and the associated renormalization factor are computed in the quenched approximation on coarse lattices using a tadpole-improved action which is corrected at the classical level to O(a^2). The improvement is displayed by comparing to Wilson action calculations.
Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics
Jo, Moon-Ho
Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics Moon-Ho Jo aerogel film was characterized from its structural and chemical viewpoints. High porosity of material infrared spectroscopy (FT-IR) for their chemical states. The improved electrical properties of SiO2 aerogel
Shock wave propagation along constant sloped ocean bottoms Joseph T. Maestasa)
Shock wave propagation along constant sloped ocean bottoms Joseph T. Maestasa) Department wave equation (NPE) is a time-domain model used to calculate long- range shock propagation using a wave waves generated by explosives buried beneath mud line. VC 2014 Acoustical Society of America. [http
Control Humidity With Single-Duct, Single-Zone, Constant Air Volume System
Chen, H.; Deng, S.; Bruner, H. L.; Claridge, D. E.
2000-01-01
The lecture hall of the Richardson Petroleum Building at Texas A&M University is a large lecture hall, with a total floor area of approximately 2500 ft^2. The lecture hall was served by a constant air volume (CAV) air handling unit (AHU) which had...
Relaxation Time Constants and Apparent Diffusion Coefficients of Rat Retina at 7 Tesla
Duong, Timothy Q.
Relaxation Time Constants and Apparent Diffusion Coefficients of Rat Retina at 7 Tesla Govind Nair* and ADC of the rat eyes were measured at 50 3 50 3 800 lm at 7 Tesla. Profiles of T1, T2, T2* and ADC
The Price of Anarchy in Network Creation Games Is (Mostly) Constant
Fiat, Amos
The Price of Anarchy in Network Creation Games Is (Mostly) Constant Mat´us Mihal´ak and Jan the price of anarchy and the structure of equilibria in network creation games. A network creation game in the resulting graph of the game. In this paper we improve previously known bounds on the price of anarchy
Letters to Analytical Chemistry Effects of Constant Voltage on Time Evolution of
Santiago, Juan G.
Letters to Analytical Chemistry Effects of Constant Voltage on Time Evolution of Propagating, California 94305 We extend the analytical theory of propagating concentra- tion polarization (CP) to describe which has a significant influence on analyte concentrations and electric fields in these devices.10
680 Jones, Felderhof, Deutch Macromolecules If polymer chains are ruptured to a constant hydrody-
Deutch, John
of the Society of Polymer Science in Japan, October, 1974. References and Notes Y . Minonra, T. Kasuya, S680 Jones, Felderhof, Deutch Macromolecules If polymer chains are ruptured to a constant hydrody polymer bonds. Ac- cording to Harrington and Zimm,12polymers are considera- bly extended under a large
Overall Rate Constant Measurements of the Reaction of Chloroalkylperoxy Radicals with Nitric Oxide
Elrod, Matthew J.
abundant alkenessethene, propene, 1-butene, 2-butene, 2-methylpropene, 1,3-butadiene, and isoprene (2-methyl-1,3-butadiene)swere determined for the first time via the turbulent flow technique and pseudo, whereas the corresponding rate constants for 1,3-butadiene and isoprene were both 20% higher than
Proofs of Retrievability with Public Verifiability and Constant Communication Cost in Cloud
International Association for Cryptologic Research (IACR)
Proofs of Retrievability with Public Verifiability and Constant Communication Cost in Cloud Jiawei, requires prior specific permission and/or a fee. CloudComputing'13, May 8, 2013, Hangzhou, China. Copyright 2013 ACM 978-1-4503-2067-2/13/05 ...$15.00. Keywords Proofs of Retrievability, Cloud Storage, Public
TYPE OF OPERATION R Research & Development T& Facility Type
Office of Legacy Management (LM)
-- R Research & Development T& Facility Type 0 Production scale testing a Pilat scale Y-. Bench Scale Process i Theoretical Studies Sample & Analysis 0 Productian 0 Disposal...
The rate constant for radiative association of HF: Comparing quantum and classical dynamics
Gustafsson, Magnus, E-mail: magngu@chem.gu.se; Monge-Palacios, M.; Nyman, Gunnar [Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg (Sweden)] [Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg (Sweden)
2014-05-14
Radiative association for the formation of hydrogen fluoride through the A{sup 1}? ? X{sup 1}?{sup +} and X{sup 1}?{sup +} ? X{sup 1}?{sup +} transitions is studied using quantum and classical dynamics. The total thermal rate constant is obtained for temperatures from 10 K to 20 000 K. Agreement between semiclassical and quantum approaches is observed for the A{sup 1}? ? X{sup 1}?{sup +} rate constant above 2000 K. The agreement is explained by the fact that the corresponding cross section is free of resonances for this system. At temperatures below 2000 K we improve the agreement by implementing a simplified semiclassical expression for the rate constant, which includes a quantum corrected pair distribution. The rate coefficient for the X{sup 1}?{sup +} ? X{sup 1}?{sup +} transition is calculated using Breit–Wigner theory and a classical formula for the resonance and direct contributions, respectively. In comparison with quantum calculations the classical formula appears to overestimate the direct contribution to the rate constant by about 12% for this transition. Below about 450 K the resonance contribution is larger than the direct, and above that temperature the opposite holds. The biggest contribution from resonances is at the lowest temperature in the study, 10 K, where it is more than four times larger than the direct. Below 1800 K the radiative association rate constant due to X{sup 1}?{sup +} ? X{sup 1}?{sup +} transitions dominates over A{sup 1}? ? X{sup 1}?{sup +}, while above that temperature the situation is the opposite.
C. J. A. P. Martins; A. M. M. Pinho; R. F. C. Alves; M. Pino; C. I. S. A. Rocha; M. von Wietersheim
2015-08-25
Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant $\\alpha$, are becoming an increasingly powerful probe of new physics. Here we discuss how these measurements, combined with local atomic clock tests and Type Ia supernova and Hubble parameter data, constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling, $\\zeta$, to the electromagnetic sector) the $\\alpha$ variation. Specifically, current data tightly constrains a combination of $\\zeta$ and the present dark energy equation of state $w_0$. Moreover, in these models the new degree of freedom inevitably couples to nucleons (through the $\\alpha$ dependence of their masses) and leads to violations of the Weak Equivalence Principle. We obtain indirect bounds on the E\\"otv\\"os parameter $\\eta$ that are typically stronger than the current direct ones. We discuss the model-dependence of our results and briefly comment on how the forthcoming generation of high-resolution ultra-stable spectrographs will enable significantly tighter constraints.
Sivaramakrishnan, R.; Michael, J.V. [Chemical Sciences and Engineering Division, D-193, Bldg. 200, Argonne National Laboratory, Argonne, IL 60439 (United States)
2009-05-15
High temperature experiments were performed with the reflected shock tube technique using multi-pass absorption spectrometric detection of OH radicals at 308 nm. The present experiments span a wide T-range, 801-1347 K, and represent the first direct measurements of the title rate constants at T>500 K for cyclopentane and cyclohexane and the only high temperature measurements for the corresponding methyl derivatives. The present work utilized 48 optical passes corresponding to a total path length {proportional_to}4.2 m. As a result of this increased path length, the high [OH] detection sensitivity permitted unambiguous analyses for measuring the title rate constants. The experimental rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, can be expressed in Arrhenius form as k{sub OH+Cyclopentane}=(1.90{+-}0.30) x 10{sup -10}exp(-1705{+-}56 K/T) (813-1341 K), k{sub OH+Cyclohexane}=(1.86{+-}0.24) x 10{sup -10}exp(-1513{+-}123 K/T) (801-1347 K), k{sub OH+Methylcyclopentane}=(2.02{+-}0.19) x 10{sup -10}exp(-1799{+-}96 K/T) (859-1344 K), k{sub OH+Methylcyclohexane}=(2.55{+-}0.30) x 10{sup -10}exp(-1824{+-}114 K/T) (836-1273 K). These results and lower-T experimental data were used to obtain three parameter evaluations of the experimental rate constants for the title reactions over an even wider T-range. These experimental three parameter fits to the rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, are k{sub OH+Cyclopentane}=1.390 x 10{sup -16}T{sup 1.779}exp(97 K/T)cm{sup 3} molecule{sup -1}s{sup -1} (209-1341 K), k{sub OH+Cyclohexane}=3.169 x 10{sup -16}T{sup 1.679}exp(119 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (225-1347 K), k{sub OH+Methylcyclopentane}=6.903 x 10{sup -18}T{sup 2.148}exp(536 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (296-1344 K), k{sub OH+Methylcyclohexane}=2.341 x 10{sup -18}T{sup 2.325}exp(602 K/T)cm{sup 3}molecule{sup -1}s{sup -1} (296-1273 K). High level electronic structure methods were used to characterize the first three reactions in order to provide reliable extrapolations of the rate constants from 250-2000 K. The results of the theoretical predictions for OH + cyclohexane and OH + methylcyclopentane were sufficient to make a theoretical prediction for OH + methylcyclohexane. The present recommended rate expressions for OH with cyclohexane, and methylcyclohexane, give rate constants that are 15-25% higher (over the T-range 800-1300 K) than the rate constants utilized in recent modeling efforts aimed at addressing the oxidation of cyclohexane and methylcyclohexane. The current measurements reduce the uncertainties in rate constants for the primary cycloalkane consumption channel in a high temperature oxidation environment. (author)
Sivaramakrishnan, R.; Michael, J. V.; Chemical Sciences and Engineering Division
2009-05-01
High temperature experiments were performed with the reflected shock tube technique using multi-pass absorption spectrometric detection of OH radicals at 308 nm. The present experiments span a wide T-range, 801-1347 K, and represent the first direct measurements of the title rate constants at T>500 K for cyclopentane and cyclohexane and the only high temperature measurements for the corresponding methyl derivatives. The present work utilized 48 optical passes corresponding to a total path length 4.2 m. As a result of this increased path length, the high [OH] detection sensitivity permitted unambiguous analyses for measuring the title rate constants. The experimental rate constants in units, cm3 molecule-1 s-1, can be expressed in Arrhenius form as k{sub OH+Cyclopentane} = (1.90 {+-} 0.30) x 10{sup -10} exp(-1705 {+-} 156 K/T) (813-1341 K), k{sub OH+Cyclohexane} = (1.86 {+-} 0.24) x 10{sup -10} exp(-1513 {+-} 123 K/T) (801-1347 K), k{sub OH+Methylcyclopentane} = (2.02 {+-} 0.19) x 10{sup -10} exp(-1799 {+-} 96 K/T) (859-1344 K), k{sub OH+Methylcyclohexane} = (2.55 {+-} 0.30) x 10{sup -10} exp(-1824 {+-} 114 K/T) (836-1273 K). These results and lower-T experimental data were used to obtain three parameter evaluations of the experimental rate constants for the title reactions over an even wider T-range. These experimental three parameter fits to the rate constants in units, cm{sup 3} molecule{sup -1} s{sup -1}, are k{sub OH+Cyclopentane} = 1.390 x 10{sup -16}T{sup 1.779} exp(97 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (209-1341 K), k{sub OH+Cyclohexane} = 3.169 x 10{sup -16} T{sup 1.679} exp(119 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (225-1347 K), k{sub OH+Methylcyclopentane} = 6.903 x 10{sup -18}T{sup 2.148} exp(536 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (296-1344 K), k{sub OH+Methylcyclohexane} = 2.341 x 10{sup -18}T{sup 2.325} exp(602 K/T) cm{sup 3} molecule{sup -1} s{sup -1} (296-1273 K). High level electronic structure methods were used to characterize the first three reactions in order to provide reliable extrapolations of the rate constants from 250-2000 K. The results of the theoretical predictions for OH + cyclohexane and OH + methylcyclopentane were sufficient to make a theoretical prediction for OH + methylcyclohexane. The present recommended rate expressions for OH with cyclohexane, and methylcyclohexane, give rate constants that are 15-25% higher (over the T-range 800-1300 K) than the rate constants utilized in recent modeling efforts aimed at addressing the oxidation of cyclohexane and methylcyclohexane. The current measurements reduce the uncertainties in rate constants for the primary cycloalkane consumption channel in a high temperature oxidation environment.
Maintenance Types | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
requirements of any physical asset within its operating context. Chapter 5 of the Federal Energy Management Program's O&M Best Practices Guide outlines these maintenance types in...
Portfolio Manager Space Type Discussion
Broader source: Energy.gov [DOE]
This presentation, given through the DOE's Technical Assistance Program (TAP), provides a discussion about space/type in regards to the Portfolio Manager Initiative.
Window Types | Department of Energy
Broader source: Energy.gov (indexed) [DOE]
its U-factor. There are advantages and disadvantages to all types of frame materials, but vinyl, wood, fiberglass, and some composite frame materials provide greater...
Portfolio Manager Space Type Discussion
Broader source: Energy.gov [DOE]
This presentation, given through the DOE's Technical Assitance Program (TAP), provides a discussion about space/type in regards to the Portfolio Manager Initiative.
Nominalization, Predication and Type Containment
Kamareddine, Fairouz
of Eindhoven, for their nancial support and hospitality during the academic year 1991{92. yKlein's work has by the uk Economic and Social Research Council. 1 #12;Abstract In an attempt to accommodate natural language, by assigning each expression a family of types. Another line of work has moved in the direction of type
Archived Reference Building Type: Warehouse
Broader source: Energy.gov [DOE]
Here you will find past versions of the commercial reference building models for existing buildings constructed in or after 1980, organized by building type and location. A summary of building types and climate zones is available for reference. Current versions are also available.
Archived Reference Building Type: Warehouse
Broader source: Energy.gov [DOE]
Here you will find past versions of the commercial reference building models for existing buildings constructed before 1980, organized by building type and location. A summary ofbuilding types and climate zones is available for reference. Current versions are also available.
Taylor, DeCarlos E., E-mail: decarlos.e.taylor.civ@mail.mil [U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)
2014-08-07
The elastic constants of the ? and ? polymorphs of cyclotrimethylene trinitramine (RDX) have been computed using dispersion corrected density functional theory (DFT). The DFT results validate the values obtained in several experiments using ultrasonic and impulsive stimulated thermal scattering techniques and disagree with those obtained using Brillouin scattering which, in general, exceed the other experimental and theoretical results. Compressibility diagrams at zero pressure are presented for the ab, ac, and bc crystallographic planes, and the anisotropic linear compressibility within the ac plane of ?-RDX at 0?GPa, observed using ultrasonic and impulsive stimulated thermal scattering measurements, is verified using DFT. The pressure dependence of the elastic constants of ?-RDX (0–4?GPa) and ?-RDX (4–8?GPa) is also presented.
Infinite slabs and other weird plane symmetric space-times with constant positive density
Ricardo E. Gamboa Saravi
2007-09-20
We present the exact solution of Einstein's equation corresponding to a static and plane symmetric distribution of matter with constant positive density located below $z=0$. This solution depends essentially on two constants: the density $\\rho$ and a parameter $\\kappa$. We show that this space-time finishes down below at an inner singularity at finite depth. We match this solution to the vacuum one and compute the external gravitational field in terms of slab's parameters. Depending on the value of $\\kappa$, these slabs can be attractive, repulsive or neutral. In the first case, the space-time also finishes up above at another singularity. In the other cases, they turn out to be semi-infinite and asymptotically flat when $z\\to\\infty$. We also find solutions consisting of joining an attractive slab and a repulsive one, and two neutral ones. We also discuss how to assemble a "gravitational capacitor" by inserting a slice of vacuum between two such slabs.
(Super)Oscillator on CP(N) and Constant Magnetic Field
Stefano Bellucci; Armen Nersessian
2005-03-12
We define the "maximally integrable" isotropic oscillator on CP(N) and discuss its various properties, in particular, the behaviour of the system with respect to a constant magnetic field. We show that the properties of the oscillator on CP(N) qualitatively differ in the N>1 and N=1 cases. In the former case we construct the ``axially symmetric'' system which is locally equivalent to the oscillator. We perform the Kustaanheimo-Stiefel transformation of the oscillator on CP(2) and construct some generalized MIC-Kepler problem. We also define a N=2 superextension of the oscillator on CP(N) and show that for N>1 the inclusion of a constant magnetic field preserves the supersymmetry of the system.
Third- and fourth-order constants of incompressible soft solids and the acousto-elastic effect
Michel Destrade; Michael D. Gilchrist; G. Saccomandi
2013-01-29
Acousto-elasticity is concerned with the propagation of small-amplitude waves in deformed solids. Results previously established for the incremental elastodynamics of exact non-linear elasticity are useful for the determination of third- and fourth-order elastic constants, especially in the case of incompressible isotropic soft solids, where the expressions are particularly simple. Specifically, it is simply a matter of expanding the expression for $\\rho v^2$, where $\\rho$ is the mass density and v the wave speed, in terms of the elongation $e$ of a block subject to a uniaxial tension. The analysis shows that in the resulting expression: $\\rho v^2 = a + be + ce^2$, say, $a$ depends linearly on $\\mu$; $b$ on $\\mu$ and $A$; and $c$ on $\\mu$, $A$, and $D$, the respective second-, third, and fourth-order constants of incompressible elasticity, for bulk shear waves and for surface waves.
Infrared Spectra and Optical Constants of Astronomical Ices: II. Ethane and Ethylene
Hudson, R L; Moore, M H
2015-01-01
Infrared spectroscopic observations have established the presence of hydrocarbon ices on Pluto and other TNOs, but the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. In this paper we present our recent measurements of near- and mid-infrared optical constants for ethane (C$_2$H$_6$) and ethylene (C$_2$H$_4$) in multiple ice phases and at multiple temperatures. As in our recent work on acetylene (C$_2$H$_2$), we also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible, and electronic versions of our new results are made available.
p=constant compression on loose Hostun sand: The case of an anisotropic response
P. Evesque
2005-07-08
Experimental data from axially symmetric compression test at constant mean pressure p on Hostun sand from Flavigny experiments on loose sands are used to study the validity of an "isotropic" modelling at different densities . It is found that the material response is not isotropic even at small deviatoric stress. As an "isotropic" behaviour is found for compression test at constant volume on the same sand, this new result questions the unicity of the trajectory in the classical phase space of soil mechanics (q,p,v), with q being thed deviatoric stress, v the specific volume. This asks whether the space shall be taken larger than 3d or not. Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn
Dynamic cancellation of a cosmological constant and approach to the Minkowski vacuum
Klinkhamer, F R
2016-01-01
The $q$-theory approach to the cosmological constant problem is reconsidered. The new observation is that the effective classical $q$-theory gets modified due to the backreaction of particle production by spacetime curvature, a well-established quantum effect. Also, an arbitrary cosmological constant can be added to the energy density $\\epsilon(q)$ of the action, in order to represent the effects from zero-point energies and phase transitions. The resulting dynamical equations of a spatially-flat Friedmann-Robertson-Walker universe are then found to give a steady approach to the Minkowski vacuum, with attractor behavior for a finite domain of initial boundary conditions on the fields. The approach to the Minkowski vacuum is slow and gives rise to an inflationary behavior of the particle horizon.
NLO and NNLO Low Energy Constants for $SU(2)$ Chiral Perturbation Theory
Mawhinney, R D
2015-01-01
We have performed global fits of $f_{\\pi}$ and $m_{\\pi}$, from a variety of RBC-UKQCD domain wall fermion ensembles, to $SU(2)$ partially quenched chiral perturbation theory at NNLO. We report values for 9 NLO and 8 linearly independent combinations of NNLO partially quenched low energy constants, which we compare to other lattice and phenomenological determinations. We discuss the convergence of the expansion and use our large set of low energy constants to make predictions for the pion mass splitting due to QCD isospin breaking effects and the s-wave $\\pi \\pi$ scattering lengths. We conclude that, for the range of pseudoscalar masses explored in this work, $115~\\mathrm{MeV} \\lesssim m_{\\rm PS} \\lesssim 430~\\mathrm{MeV}$, the NNLO $SU(2)$ expansion is quite robust and can fit lattice data with percent-scale accuracy.
The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature
Lamoreaux, Steve (LANL) [LANL
2005-11-07
Natural nuclear reactors? Changes in the speed of light? If either of these concepts seem implausible to you now they certainly won't once Dr. Steve Lamoreaux (LANL) delivers his SLAC Colloquium lecture in the Panofsky Auditorium on November 7th at 4:15 pm entitled The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature. This lecture is a rare opportunity to learn not only about Oklo's incredible natural nuclear reactors but also to gain understanding about how the present-day study of these sites may alter our understanding of fundamental constants such as the speed of light. This event is a must-see for the curious!
Darquié, Benoît; Sow, Papa Lat Tabara; Lemarchand, Cyril; Triki, Meriam; Tokunaga, Sean; Bordé, Christian J; Chardonnet, Christian; Daussy, Christophe
2015-01-01
Accurate molecular spectroscopy in the mid-infrared region allows precision measurements of fundamental constants. For instance, measuring the linewidth of an isolated Doppler-broadened absorption line of ammonia around 10 $\\mu$m enables a determination of the Boltzmann constant k B. We report on our latest measurements. By fitting this lineshape to several models which include Dicke narrowing or speed-dependent collisional effects, we find that a determination of k B with an uncertainty of a few ppm is reachable. This is comparable to the best current uncertainty obtained using acoustic methods and would make a significant contribution to any new value of k B determined by the CODATA. Furthermore, having multiple independent measurements at these accuracies opens the possibility of defining the kelvin by fixing k B, an exciting prospect considering the upcoming redefinition of the International System of Units.
Measurement of the pure dissolution rate constant of a mineral in water
Jean Colombani
2009-11-26
We present here a methodology, using holographic interferometry, enabling to measure the pure surface reaction rate constant of the dissolution of a mineral in water, unambiguously free from the influence of mass transport. We use that technique to access to this value for gypsum and we demonstrate that it was never measured before but could be deduced a posteriori from the literature results if hydrodynamics is taken into account with accuracy. It is found to be much smaller than expected. This method enables to provide reliable rate constants for the test of dissolution models and the interpretation of in situ measurements, and gives clues to explain the inconsistency between dissolution rates of calcite and aragonite, for instance, in the literature.
A Novel Active Bouncer System for Klystron Modulators with Constant AC Power Consumption
Cabaleiro Magallanes, F; Viarouge, P; Cros, J; De Almeida Martins, C
2014-01-01
This paper presents the principles and design methodologies of a novel active bouncer system, to be implemented in a transformer-based klystron modulator, which is able to meet two different objectives: 1. Regulate the output pulse voltage flattop, and 2. Attenuate the power fluctuation withdrawn from the AC network. This solution allows the utilization of a standard constant voltage / constant current power supply as a capacitor charger. The solution consists of a 4-quadrant switching converter placed in series with the main capacitor bank (forming a unique element in parallel with the capacitor charger), controlled with specific feed-back loops to achieve the two objectives. The complete design method, including a numerical optimization, of the whole system, is presented in the paper. Analyses of the compromises between the active bouncer specifications and the other modulator sub-components design is presented as well.
Constants of the Motion in a Gravitational Field and the Hamilton-Jacobi Function
Paul O'Hara
2012-08-25
In most text books of mechanics, Newton's laws or Hamilton's equations of motion are first written down and then solved based on initial conditions to determine the constants of the motions and to describe the trajectories of the particles. In this essay, we take a different starting point. We begin with the metrics of general relativity and show how they can be used to construct by inspection constants of motion, which can then be used to write down the equations of the trajectories. This will be achieved by deriving a Hamiltonian-Jacobi function from the metric and showing that its existence requires all of the above mentioned properties. The article concludes with four applications, which includes a derivation of Kepler's First Law of Motion for planets, and a formula for describing the trajectories of galaxies moving in a space defined by the Robertson-Walker metric.
Light pseudoscalar meson masses and decay constants from mixed action lattice QCD
Christopher Aubin; Jack Laiho; Ruth S. Van de Water
2008-10-23
We calculate the light pseudoscalar decay constants, f_pi and f_K, and their ratio using domain wall valence quarks and 2+1 flavors of dynamical staggered quarks. Use of the MILC gauge configurations allows us to simulate at several sea quark masses and spatial volumes, and with two lattice spacings. We study how well our numerical lattice data for light decay constants and meson masses is described by next-to-leading order SU(3) mixed action chiral perturbation theory and explain our strategy for the chiral and continuum extrapolation. Combining our result for f_K/f_pi with experimental measurements of pion and kaon leptonic decays allows a model-independent determination of |V_us|/|V_ud|; we find a preliminary value of |V_us|/|V_ud| = 0.2315(45)(7).
Heavy-light decay constants---MILC results with the Wilson action
MILC Collaboration; Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; Jim Hetrick; Craig McNeile; Kari Rummukainen; A. Soni; Bob Sugar; Doug Toussaint; Matthew Wingate
1997-07-15
We present the current status of our ongoing calculations of pseudoscalar meson decay constants for mesons that contain one light and one heavy quark (f_B, f_{B_s}, f_D, f_{D_s}). We are currently generating new gauge configurations that include dynamical quarks and calculating the decay constants. In addition, we have several new results for the static approximation. Those results, as well as several refinements to the analysis, are new since Lattice '96. Our current (still preliminary) value for f_B is 156 +- 11 +- 30 +- 14 MeV, where the first error is from statistical and fitting errors, the second error is an estimate of other systematic errors within the quenched approximation and the third error is an estimate of the quenching error. For the ratio f_{B_s}/f_B, we get 1.11 +- 0.02 +- 0.03 +- 0.07.
Measurement of the pure dissolution rate constant of a mineral in water
Colombani, Jean
2009-01-01
We present here a methodology, using holographic interferometry, enabling to measure the pure surface reaction rate constant of the dissolution of a mineral in water, unambiguously free from the influence of mass transport. We use that technique to access to this value for gypsum and we demonstrate that it was never measured before but could be deduced a posteriori from the literature results if hydrodynamics is taken into account with accuracy. It is found to be much smaller than expected. This method enables to provide reliable rate constants for the test of dissolution models and the interpretation of in situ measurements, and gives clues to explain the inconsistency between dissolution rates of calcite and aragonite, for instance, in the literature.
HQET at order 1/m: III. Decay constants in the quenched approximation
Benoît Blossier; Michele Della Morte; Nicolas Garron; Georg von Hippel; Tereza Mendes; Hubert Simma; Rainer Sommer
2010-10-25
We report on the computation of the $B_s$ meson decay constant in Heavy Quark Effective Theory on the lattice. The next to leading order corrections in the HQET expansion are included non-perturbatively. We estimate higher order contributions to be very small. The results are extrapolated to the continuum limit, the main systematic error affecting the computation is therefore the quenched approximation used here. The Generalized Eigenvalue Problem and the use of all-to-all propagators are important technical ingredients of our approach that allow to keep statistical and systematic errors under control. We also report on the decay constant $f_{B'_s}$ of the first radially excited state in the $B_s$ sector, computed in the static limit.
Tsunami and acoustic-gravity waves in water of constant depth
Hendin, Gali; Stiassnie, Michael
2013-08-15
A study of wave radiation by a rather general bottom displacement, in a compressible ocean of otherwise constant depth, is carried out within the framework of a three-dimensional linear theory. Simple analytic expressions for the flow field, at large distance from the disturbance, are derived. Realistic numerical examples indicate that the Acoustic-Gravity waves, which significantly precede the Tsunami, are expected to leave a measurable signature on bottom-pressure records that should be considered for early detection of Tsunami.
Exact solution to the Landau-Lifshitz equation in a constant electromagnetic field
Yurij Yaremko
2014-12-04
We are interested in the motion of a classical charge acted upon an external constant electromagnetic field where the back reaction of the particle's own field is taken into account. The Landau-Lifshitz approximation to the Lorentz-Abraham-Dirac equation is solved exactly and in closed form. It is shown that the ultrarelativistic limit of the Landau-Lifshitz equation for a radiating charge is the equation for eigenvalues and eigenvectors of the external electromagnetic field tensor.
Masses, decay constants and electromagnetic form-factors with twisted boundary conditions
Bijnens, Johan
2015-01-01
We discuss some of the effects of twisted boundary conditions in finite volume using continuum SU(3) Chiral Perturbation Theory. We point out how broken cubic symmetry affects the definitions of quantities such as form-factors. Using the $\\pi^+$ as an example, we give one loop results for the mass, decay constants and electromagnetic form-factor and illustrate how the relevant Ward identities are satisfied.
Masses, decay constants and electromagnetic form-factors with twisted boundary conditions
Johan Bijnens; Johan Relefors
2015-09-24
We discuss some of the effects of twisted boundary conditions in finite volume using continuum SU(3) Chiral Perturbation Theory. We point out how broken cubic symmetry affects the definitions of quantities such as form-factors. Using the $\\pi^+$ as an example, we give one loop results for the mass, decay constants and electromagnetic form-factor and illustrate how the relevant Ward identities are satisfied.
Strong coupling constants of heavy baryons with light mesons in QCD
Aliev, T. M.; Azizi, K.; Savci, M.
2012-10-23
The strong coupling constants of the heavy spin-1/2 and spin-3/2 baryons with light pseudoscalar and vector mesons are calculated in the framework of the light cone QCD sum rules. Using the symmetry arguments, some structure independent relations among different correlation functions are obtained. It is shown that all possible transitions are described by only one invariant function, whose explicit expression is structure dependent.
Delay Time ConstantAnalysis for5 Optimization in RF Si/SiGeBipolar Devices
Ng, Wai Tung
Delay Time ConstantAnalysis for5 Optimization in RF Si/SiGeBipolar Devices I-S.M. Sun,H. E. Xu, R, the optimization of the SiGe epitaxial base, intrinsic collector and base doping profiles, and extrinsic collector restrict the degrees of freedom in device optimization. Furthermore, T S . M. Sun, H.E. Xu, R Tam and W. T
Variation of calibration constant of alpha track detectors with respect to altitude
Vasudevan, Latha
1991-01-01
. Cellulose nitrate LR 115 II alpha track detectors were exposed in two different configurations (open and closed) in a known radon atmosphere to obtain an appropriate calibration constant (tracks cm '/kBq-h-m') for the LR 115 II film. The establishment... detector film and its corresponding integrated radon exposure. The fundamental limitation on the accuracy and precision of ATD measurements is dependent on the Poisson counting statistics associated with the total number of tracks counted (Alter...
Computation of the O(p^6) order low-energy constants: an update
Shao-Zhou Jiang; Zhen-Long Wei; Qing-Sen Chen; Qing Wang
2015-02-17
We update our original low-energy constants to the O(p6) order, including two and three flavours, the normal and anomalous ones. Following a comparative analysis, the O(p4) results are considered better. In the O(p6) order, most of our results are consistent or better with those we have found in the literature, although several are worse.
Future stability of the FLRW fluid solutions in the presence of a positive cosmological constant
Todd A. Oliynyk
2015-05-05
We introduce a new method for establishing the future non-linear stability of perturbations of FLRW solutions to the Einstein-Euler equations with a positive cosmological constant and a linear equation of state of the form $\\rho = K p$. The method is based on a conformal transformation of the Einstein-Euler equations that compactifies the time domain and can handle the equation of state parameter values $0future.
PROPERTY TABLES AND CHARTS (SI UNITS) Table A1 Molar mass, gas constant, and
Kostic, Milivoje M.
Table A20 Ideal-gas properties of carbon dioxide, CO2 Table A21 Ideal-gas properties of carbon.1355 n-Butane C4H10 58.124 0.1430 425.2 3.80 0.2547 Carbon dioxide CO2 44.01 0.1889 304.2 7.39 0Appendix 1 PROPERTY TABLES AND CHARTS (SI UNITS) Table A1 Molar mass, gas constant, and critical
Quantization of a particle on a two-dimensional manifold of constant curvature
Bracken, Paul [Department of Mathematics, University of Texas, Edinburg, Texas 78540 (United States)
2014-10-15
The formulation of quantum mechanics on spaces of constant curvature is studied. It is shown how a transition from a classical system to the quantum case can be accomplished by the quantization of the Noether momenta. These can be determined by means of Lie differentiation of the metric which defines the manifold. For the metric examined here, it is found that the resulting Schrödinger equation is separable and the spectrum and eigenfunctions can be investigated in detail.
Limiting electron beam current for cyclic induction acceleration in a constant guide field
Kanunnikov, V.N.
1982-09-01
Theoretical relations are derived for the limiting beam current in a cyclic induction accelerator (CIA) with a constant guide field. The calculations are in agreement with the available experimental data. It is shown that the limiting average beam current in a CIA is of the order of 100 microamperes, i.e., the level attained in microtrons and linear accelerators. The CIA may find industrial applications.
Decay constants of heavy-light vector mesons from QCD sum rules
Patrick Gelhausen; Alexander Khodjamirian; Alexei A. Pivovarov; Denis Rosenthal
2015-03-27
We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons B^*_(s) and D^*_(s) we improve the accuracy of OPE, taking into account the O(alpha_s^2) terms in the perturbative part and calculating the O(alpha_s) corrections to the quark-condensate contribution. With this accuracy, we obtain the ratios of decay constants: f_B^*/f_B=1.02 +0.07 -0.03, f_D^*/f_D=1.20 +0.10 -0.07. The sum rule predictions for the decay constants of pseudoscalar mesons are updated with the results f_B=(207 +17 -9) MeV, f_B_s=(242 +17 -12) MeV, f_D=(201 +12 -13) MeV, f_D_s=(238 +13 -23) MeV. In order to assess the sensitivity of our calculation to the form of the sum rule, we consider alternative versions such as the power moments and Borel sum rules with different weights of the spectral density. We also investigated the heavy quark limit of the sum rules for vector and pseudoscalar mesons, estimating the violations of the heavy-quark spin and flavour symmetry.
HYPERFINE STRUCTURE CONSTANTS OF ENERGETICALLY HIGH-LYING LEVELS OF ODD PARITY OF ATOMIC VANADIUM
Güzelçimen, F.; Yap?c?, B.; Demir, G.; Er, A.; Öztürk, I. K.; Ba?ar, Gö.; Kröger, S.; Tamanis, M.; Ferber, R.; Docenko, D.; Ba?ar, Gü. E-mail: sophie.kroeger@htw-berlin.de
2014-09-01
High-resolution Fourier transform spectra of a vanadium-argon plasma have been recorded in the wavelength range of 365-670 nm (15,000-27,400 cm{sup –1}). Optical bandpass filters were used in the experimental setup to enhance the sensitivity of the Fourier transform spectrometer. In total, 138 atomic vanadium spectral lines showing resolved or partially resolved hyperfine structure have been analyzed to determine the magnetic dipole hyperfine structure constants A of the involved energy levels. One of the investigated lines has not been previously classified. As a result, the magnetic dipole hyperfine structure constants A for 90 energy levels are presented: 35 of them belong to the configuration 3d {sup 3}4s4p and 55 to the configuration 3d {sup 4}4p. Of these 90 constants, 67 have been determined for the first time, with 23 corresponding to the configuration 3d {sup 3}4s4p and 44 to 3d {sup 4}4p.
An explanation for the tiny value of the cosmological constant and the low vacuum energy density
Nassif, Cláudio
2015-01-01
The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in space-time by means of the elimination of the classical idea of rest, by including an invariant minimum limit of speed in the subatomic world. Such a minimum speed, unattainable by particles, represents a preferred reference frame associated with a background field that breaks down the Lorentz symmetry. The metric of the flat space-time shall include the presence of a uniform vacuum energy density, which leads to a negative pressure at cosmological length scales. Thus, the equation of state for the cosmological constant [$p$(pressure)$=- \\epsilon$ (energy density)] naturally emerges from such a space-time with an energy barrier of a minimum speed. The tiny values of the cosmological constant and the vacuum energy density will be successfully obtained, being in agreement with the obs...
Discrete accidental symmetry for a particle in a constant magnetic field on a torus
Al-Hashimi, M.H. Wiese, U.-J.
2009-02-15
A classical particle in a constant magnetic field undergoes cyclotron motion on a circular orbit. At the quantum level, the fact that all classical orbits are closed gives rise to degeneracies in the spectrum. It is well-known that the spectrum of a charged particle in a constant magnetic field consists of infinitely degenerate Landau levels. Just as for the 1/r and r{sup 2} potentials, one thus expects some hidden accidental symmetry, in this case with infinite-dimensional representations. Indeed, the position of the center of the cyclotron circle plays the role of a Runge-Lenz vector. After identifying the corresponding accidental symmetry algebra, we re-analyze the system in a finite periodic volume. Interestingly, similar to the quantum mechanical breaking of CP invariance due to the {theta}-vacuum angle in non-Abelian gauge theories, quantum effects due to two self-adjoint extension parameters {theta}{sub x} and {theta}{sub y} explicitly break the continuous translation invariance of the classical theory. This reduces the symmetry to a discrete magnetic translation group and leads to finite degeneracy. Similar to a particle moving on a cone, a particle in a constant magnetic field shows a very peculiar realization of accidental symmetry in quantum mechanics.
An explanation for the tiny value of the cosmological constant and the low vacuum energy density
Cláudio Nassif
2015-09-28
The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in space-time by means of the elimination of the classical idea of rest, by including an invariant minimum limit of speed in the subatomic world. Such a minimum speed, unattainable by particles, represents a preferred reference frame associated with a background field that breaks down the Lorentz symmetry. The metric of the flat space-time shall include the presence of a uniform vacuum energy density, which leads to a negative pressure at cosmological length scales. Thus, the equation of state for the cosmological constant [$p$(pressure)$=- \\epsilon$ (energy density)] naturally emerges from such a space-time with an energy barrier of a minimum speed. The tiny values of the cosmological constant and the vacuum energy density will be successfully obtained, being in agreement with the observational results of Perlmutter, Schmidt and Riess.
New approaches for modeling type Ia supernovae
Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan
2007-01-01
runaway in Type Ia supernovae: How to run away? oIgnition in Type Ia Supernovae. II. A Three- dimensionalnumber modeling of type Ia supernovae. I. hydrodynamics.
Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)
1997-01-01
Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.
Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.
1997-08-12
Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.
Truong, Thanh N.
-flux correlation function for calculating the thermal rate constants of chemical reactions in solution in this study would provide a complete tool for studying the quantum dynamics of chemical reactions the thermal chemical reaction rate constants. Furthermore, we also employ an efficient and accurate quantum
Renata Kallosh; Masoud Soroush
2007-06-09
Moduli stabilization in the type IIA massive string theory so far was achieved only in the AdS vacua. The uplifting to dS vacua has not been performed as yet: neither the analogs of type IIB anti-D3 brane at the tip of the conifold, nor the appropriate D-terms have been identified. The hope was recently expressed that the F-term uplifting may work. We investigate this possibility in the context of a simplified version of the type IIA model developed in hep-th/0505160 and find that the F-term does not uplift the AdS vacua to dS vacua with positive CC. Thus it remains a challenging task to find phenomenologically acceptable vacua in the type IIA string theory.
On the vacuum fluctuations and the cosmological constant: Comment on the paper by T.Padmanabhan
V. G. Gurzadyan; S. -S. Xue
2006-03-05
The formula for the dark energy, derived by Padmanabhan in a recent Letter to Editor (Class.Quantum Grav. September 2005, the formula given in its Abstract), was actually derived 4 years earlier ourselves in astro-ph/0105245; Mod.Phys.Lett. A18, 561, 2003. Among dozens of references in that Letter, no quotation to our paper. Based on the same Zeldovich idea on vacuum fluctuations, Padmanabhan derives it from scaling considerations, while we had gone into more details and shown that the formula fits the observed value of the cosmological constant if l=0 modes are relevant.
From the Cosmological Constant: Higgs Boson, Dark Matter, and Quantum Gravity Scales
James R. Bogan
2010-11-08
We suggest discovery targets for the Higgs boson, dark matter, and quantum gravity mass scales, motivated by the Dirac equation for the electron in deSitter space, and a sixth-order constraint between the electron QED parameters and the cosmological constant. We go on to show that this constraint can be viewed as a structural parameter of the electron, and leads naturally to a new cosmic horizon. A dual fourth-order constraint implies a second-order one, from which the electron neutrino mass is derived.
Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant
MuLan Collaboration; D. B. Chitwood; T. I. Banks; M. J. Barnes; S. Battu; R. M. Carey; S. Cheekatmalla; S. M. Clayton; J. Crnkovic; K. M. Crowe; P. T. Debevec; S. Dhamija; W. Earle; A. Gafarov; K. Giovanetti; T. P. Gorringe; F. E. Gray; M. Hance; D. W. Hertzog; M. F. Hare; P. Kammel; B. Kiburg; J. Kunkle; B. Lauss; I. Logashenko; K. R. Lynch; R. McNabb; J. P. Miller; F. Mulhauser; C. J. G. Onderwater; C. S. Ozben; Q. Peng; C. C. Polly; S. Rath; B. L. Roberts; V. Tishchenko; G. D. Wait; J. Wasserman; D. M. Webber; P. Winter; P. A. Zolnierczuk
2008-02-08
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.
Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field
Casada, Donald A. (Knoxville, TN); Haynes, Howard D. (Knoxville, TN)
1993-01-01
One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.
Quintessential inflation from a variable cosmological constant in a 5D vacuum
Agustin Membiela; Mauricio Bellini
2007-05-16
We explore an effective 4D cosmological model for the universe where the variable cosmological constant governs its evolution and the pressure remains negative along all the expansion. This model is introduced from a 5D vacuum state where the (space-like) extra coordinate is considered as noncompact. The expansion is produced by the inflaton field, which is considered as nonminimally coupled to gravity. We conclude from experiental data that the coupling of the inflaton with gravity should be weak, but variable in different epochs of the evolution of the universe.
Testing of Dark Energy and a Solution of the Cosmological Constant Problem
Vladimir Burdyuzha
2014-01-19
A probable solution of the cosmological constant problem was recently found. We propose that dark energy of the Universe is vacuum energy. Our Universe during its expansion is spending its vacuum energy for creation of new quantum states, but in the quantum regime phase transitions were more effective in reducing the vacuum energy than creation of new quantum states. Here we show how the 123 crisis orders of the vacuum energy are reduced by conventional physical processes in both the quantum and classical regimes of the Universe evolution. Numeral estimates of dark energy evolution are also presented.
Light vector meson decay constants and the renormalization factor from a tadpole-improved action
Randy Lewis; R. M. Woloshyn
1996-10-18
The rho, K* and phi decay constants and the vector current renormalization factor are studied by using an O(a^2) classically-improved, tadpole-improved action. Tree-level calculations are used to show how the classical improvement of the action, involving next-nearest-neighbour timesteps, is transferred to the matrix elements. Simulations are performed on coarse lattices and compared to Wilson results from both coarse and fine lattices. The improved action data are found to resemble Wilson data obtained at 1/3 of the lattice spacing, which is the same degree of improvement that is seen by comparing the mass spectra.
Non-perturbative computation of the strong coupling constant on the lattice
Sommer, Rainer
2015-01-01
We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically carry out the required multiscale non-perturbative calculation with our special emphasis on the control of systematic errors are summarized. The complete results in the two dynamical flavor approximation are reviewed and an outlook is given on the ongoing three flavor extension of the programme with improved target precision.
Non-perturbative computation of the strong coupling constant on the lattice
Rainer Sommer; Ulli Wolff
2015-01-08
We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically carry out the required multiscale non-perturbative calculation with our special emphasis on the control of systematic errors are summarized. The complete results in the two dynamical flavor approximation are reviewed and an outlook is given on the ongoing three flavor extension of the programme with improved target precision.
Jamie M. Foster; Dmitry E. Pelinovsky
2015-06-16
We consider the slow nonlinear diffusion equation subject to a constant absorption rate and construct local self-similar solutions for reversing (and anti-reversing) interfaces, where an initially advancing (receding) interface gives way to a receding (advancing) one. We use an approach based on invariant manifolds, which allows us to determine the required asymptotic behaviour for small and large values of the concentration. We then `connect' the requisite asymptotic behaviours using a robust and accurate numerical scheme. By doing so, we are able to furnish a rich set of self-similar solutions for both reversing and anti-reversing interfaces.
Reduction of iron-oxide-carbon composites: part I. Estimation of the rate constants
Halder, S.; Fruehan, R.J. [Praxair Inc., Tonawanda, NY (United States). Technological Center
2008-12-15
A new ironmaking concept using iron-oxide-carbon composite pellets has been proposed, which involves the combination of a rotary hearth furnace (RHF) and an iron bath smelter. This part of the research focuses on studying the two primary chemical kinetic steps. Efforts have been made to experimentally measure the kinetics of the carbon gasification by CO{sub 2} and wustite reduction by CO by isolating them from the influence of heat- and mass-transport steps. A combined reaction model was used to interpret the experimental data and determine the rate constants. Results showed that the reduction is likely to be influenced by the chemical kinetics of both carbon oxidation and wustite reduction at the temperatures of interest. Devolatilized wood-charcoal was observed to be a far more reactive form of carbon in comparison to coal-char. Sintering of the iron-oxide at the high temperatures of interest was found to exert a considerable influence on the reactivity of wustite by virtue of altering the internal pore surface area available for the reaction. Sintering was found to be predominant for highly porous oxides and less of an influence on the denser ores. It was found using an indirect measurement technique that the rate constants for wustite reduction were higher for the porous iron-oxide than dense hematite ore at higher temperatures (> 1423 K). Such an indirect mode of measurement was used to minimize the influence of sintering of the porous oxide at these temperatures.
Asymptotically (anti)-de Sitter solutions in Gauss-Bonnet gravity without a cosmological constant
Dehghani, M.H.
2004-09-15
In this paper I show that one can have asymptotically de Sitter, anti-de Sitter (AdS), and flat solutions in Gauss-Bonnet gravity without a cosmological constant term in field equations. First, I introduce static solutions whose three surfaces at fixed r and t have constant positive (k=1), negative (k=-1), or zero (k=0) curvature. I show that for k={+-}1 one can have asymptotically de Sitter, AdS, and flat spacetimes, while for the case of k=0, one has only asymptotically AdS solutions. Some of these solutions present naked singularities, while some others are black hole or topological black hole solutions. I also find that the geometrical mass of these five-dimensional spacetimes is m+2{alpha}|k|, which is different from the geometrical mass m of the solutions of Einstein gravity. This feature occurs only for the five-dimensional solutions, and is not repeated for the solutions of Gauss-Bonnet gravity in higher dimensions. Second, I add angular momentum to the static solutions with k=0, and introduce the asymptotically AdS charged rotating solutions of Gauss-Bonnet gravity. Finally, I introduce a class of solutions which yields an asymptotically AdS spacetime with a longitudinal magnetic field, which presents a naked singularity, and generalize it to the case of magnetic rotating solutions with two rotation parameters.
The hierarchy problem and the cosmological constant problem in the Standard Model
Fred Jegerlehner
2015-03-03
We argue that the SM in the Higgs phase does not suffer form a "hierarchy problem" and that similarly the "cosmological constant problem" resolves itself if we understand the SM as a low energy effective theory emerging from a cut-off medium at the Planck scale. We discuss these issues under the condition of a stable Higgs vacuum, which allows to extend the SM up to the Planck length. The bare Higgs boson mass then changes sign below the Planck scale, such the the SM in the early universe is in the symmetric phase. The cut-off enhanced Higgs mass term as well as the quartically enhanced cosmological constant term trigger the inflation of the early universe. The coefficients of the shift between bare and renormalized Higgs mass as well as of the shift between bare and renormalized vacuum energy density exhibit close-by zeros at some point below the Planck scale. The zeros are matching points between short distance and the renormalized low energy quantities. Since inflation tunes the total energy density to take the critical value of a flat universe Omega_tot=rho_tot/rho_crit=Omega_Lambda+Omega_matter+Omega_radiation}=1 it is obvious that Omega_Lambda today is of order Omega_tot given that 1>Omega_matter, Omega_radiation>0, which saturate the total density to about 26 % only, the dominant part being dark matter(21 %).
Christopher G. Jesudason
2011-01-26
The primary emphasis of this work on kinetics is to illustrate the a posteriori approach to applications, where focus on data leads to novel outcomes, rather than the a priori tendencies of applied analysis which imposes constructs on the nature of the observable. The secondary intention is the development of appropriate methods consonant with experimental definitions. By focusing on gradients, it is possible to determine both the average and instantaneous rate constants that can monitor changes in the rate constant with concentration changes as suggested by this theory. Here, methods are developed and discussed utilizing nonlinear analysis which does not require exact knowledge of initial concentrations. These methods are compared with those derived from standard methodology. These gradient methods are shown to be consistent with the ones from standard methods and could readily serve as alternatives for studies where there are limits or unknowns in the initial conditions, such as in the burgeoning fields of astrophysics and astrochemistry, forensics, archeology and biology . All four reactions studied exhibited semi sinusoidal-like change with reactant concentration change which standard methods cannot detect, which seems to constitute the observation of a new effect that is not predicted by current formulations, where the possibility that the observations are due to artifacts from instrumental errors or the optimization method is reasoned as unlikely since the experiments were conducted by different groups at very different times with different classes of reactions.
Equation of State in Relativistic Magnetohydrodynamics: variable versus constant adiabatic index
A. Mignone; Jonathan C. McKinney
2007-04-13
The role of the equation of state for a perfectly conducting, relativistic magnetized fluid is the main subject of this work. The ideal constant $\\Gamma$-law equation of state, commonly adopted in a wide range of astrophysical applications, is compared with a more realistic equation of state that better approximates the single-specie relativistic gas. The paper focus on three different topics. First, the influence of a more realistic equation of state on the propagation of fast magneto-sonic shocks is investigated. This calls into question the validity of the constant $\\Gamma$-law equation of state in problems where the temperature of the gas substantially changes across hydromagnetic waves. Second, we present a new inversion scheme to recover primitive variables (such as rest-mass density and pressure) from conservative ones that allows for a general equation of state and avoids catastrophic numerical cancellations in the non-relativistic and ultrarelativistic limits. Finally, selected numerical tests of astrophysical relevance (including magnetized accretion flows around Kerr black holes) are compared using different equations of state. Our main conclusion is that the choice of a realistic equation of state can considerably bear upon the solution when transitions from cold to hot gas (or viceversa) are present. Under these circumstances, a polytropic equation of state can significantly endanger the solution.
Lumen mass transfer in hollow-fiber membrane processes with constant external resistances
Qin, Y.; Cabral, J.M.S.
1997-08-01
Membrane processes have recently become an accepted unit operation for a wide variety of separations in industry and in environmental applications. Hollow-fiber membrane processes with a constant external resistance having a constant or variable shell concentration resulting from an operational mode of cocurrent or countercurrent are studied. By solving numerically the continuity mass-conservation equation with the corresponding boundary conditions, the lumen laminar mass-transfer coefficients for both cases are correlated. The correlations greatly improve the calculating accuracy of the overall mass-transfer coefficient and can be used to obtain the lumen mixed-cup concentration by an algebraic equation substituting the partial differential equation. A separation factor m{prime} is introduced to characterize the effect of the operational mode. Calculation results demonstrate that the lumen mass-transfer coefficient is independent of the real lumen and shell concentrations, but it is greatly influenced by m{prime}. The countercurrent mode, compared to the cocurrent mode, provides not only a higher mean driving force, but a higher lumen mass-transfer coefficient. This conclusion is novel and valid for the tube-shell heat or mass-transfer processes and is supported by the experimental data in the literature and the authors` gas membrane separation experiments.
de Baubigny, Julien Dupré; Fabié, Laure; Delmas, Mathieu; Aimé, Jean-Pierre; Legros, Marc; Ondarçuhu, Thierry
2015-01-01
We investigate the shape and mechanical properties of liquid interfaces down to nanometer scale by atomic force microscopy (AFM) and scanning electron microscopy (SEM) combined with in situ micromanipulation techniques. In both cases, the interface is probed with a cylindrical nanofiber with radius R of the order of 25-100 nm. The effective spring constant of the nanomeniscus oscillated around its equilibrium position is determined by static and frequency-modulation (FM) AFM modes. In the case of an unbounded meniscus, we find that the effective spring constant k is proportional to the surface tension {\\gamma} of the liquid through k = (0.51 +- 0.06) {\\gamma}, regardless of the excitation frequency from quasistatic up to 450 kHz. A model based on the equilibrium shape of the meniscus reproduces well the experimental data. Electron microscopy allowed to visualize the meniscus profile around the fiber with a lateral resolution of the order of 10 nm and confirmed its catenary shape. The influence of a lateral co...
stay healthy, my friends PREVENT THE SPREAD
Akhmedov, Azer
secretions by close personal contact, such as coughing, sharing drinks, and kissing, or being in close NOT cough into anyone's face. Cough into your sleeve or tissue. Wash or sanitize hands frequently. drinking
Security system helps utility stay competitive
NONE
1995-04-01
Atlantic Electric is saving more than $750,000 annually in security costs by using an innovative closed-circuit television (CCTV) system to guard its remote sites electronically. Today, a single guard in the central security control room at Atlantic Electric`s headquarters electronically surveys and controls some 20 remote sites such as combustion turbine sites, material storage, administrative facilities and operating centers. Protecting these sites are CCTV cameras mounted around each yard, floodlighting, and a motion detection and signal transmission system called Adpro SiteWatch by vsion Systems Inc. The SiteWatch system automatically displays to the central guard any intrusion at a site, and captures and replays the intrusion events similar to an instant replay in a televised sporting event. Over the five year transition, Atlantic Electric saved nearly $2 million in security costs.
Staying Current: Changes & Updates September 4, 2013
Kay, Mark A.
Self-Inspection Expectations · SC County Hazardous Waste Updates and Expectations · EHS Updates deficiencies üSeparate form for areas requiring a monthly inspection http://www.stanford Hazardous Materials Compliance Division(HMCD) 1555 Berger Drive, Suite 300, San Jose, CA 95112-2716 Phone
Energy Audit Helps Small Company Stay Competitive
Broader source: Energy.gov [DOE]
The recommended improvements are saving the West Linn Paper Company in Oregon an annual cost of about $380,000.
Microsoft Word - Final stay rate 03.doc
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal CERTIFIED MAIL OctoberÂ«Customer Service11
STAY CONNECTED: In This Issue Electricity Infrastructure
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 AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV6STAT 12293GG STATESTAY CONNECTED: In This
Pramod Kumar Singh; Amreesh Chandra
2003-04-21
The dispersal of high dielectric constant ferroelectric ceramic material Ba(0.7)Sr(0.3)TiO(3) (Tc~30 C) and Ba(0.88)Sr(0.12)TiO(3) (Tc~90 C) in an ion conducting polymer electrolyte (PEO:NH4I) is reported to result in an increase in the room temperature ionic conductivity by two orders of magnitude. The conductivity enhancememt "peaks" as we approach the dielectric phase transition of the dispersed ferroelectric material where the dielectric constant changes from ~ 2000 to 4000. This establishes the role of dielectric constant of the dispersoid in enhancing the ionic conductivity of the polymeric composites.
Alberto A. Garcia Diaz
2014-12-17
Under the hydrodynamic equilibrium Buchdahl's conditions on the behavior of the density and the pressure, for regular fluid static circularly symmetric star in (2 + 1) dimensions in the presence of a cosmological constant, is established that there are no bounds from below on the pressure and also on the mass, except for their positiveness. The metric for a constant density distribution is derived and its matching with the external static solution with a negative cosmological constant is accomplished. Some mistakes of previous works on the topic are pointed out.
Type Checking Type Classes Tobias Nipkow and Christian Prehofer
. The judgement : fC1 ::: Cng is a compact form of the conjunction : C1 ^ ::: ^ : Cn. Alternatively we may think of fC1 ::: Cng as a notation for C1 \\ :::\\ Cn, the intersection of the types belonging to the classes C
The goal of Team Constant Contact is to design and construct the most efficient
Wood, Stephen L.
of attack of a Darieus type turbine. Studies indicate that this turbine is currently the most efficient low head turbine in the world. Superstructure with Darieus Blade Attachment Cover: Superstructure
Type Ia Supernova Explosion Models
W. Hillebrandt; J. C. Niemeyer
2000-06-21
Because calibrated light curves of Type Ia supernovae have become a major tool to determine the local expansion rate of the Universe and also its geometrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe that perhaps most Type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling Type Ia supernovae as well as several of the still open questions are addressed in this review. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.
Hydrogen and helium traces in type Ib-c supernovae
A. Elmhamdi; I. J. Danziger; D. Branch; B. Leibundgut; E. Baron; R. P. Kirshner
2006-04-04
The spectroscopic properties of a selected optical photospheric spectra of core collapse supernovae (CCSNe) are investigated.Special attention is devoted to traces of hydrogen at early phases. The generated spectra are found to match the observed ones reasonably well, including a list of only 23 candidate ions. Guided by SN Ib 1990I, the observed trough near 6300\\AA is attributed to H$\\alpha$ in almost all Type Ib events, although in some objects it becomes too weak to be discernible, especially at later phases. Alternative line identifications are discussed. Differences in the way hydrogen manifests its presence within CCSNe are highlighted. In Type Ib SNe, the H$\\alpha$ contrast velocity (i.e. line velocity minus the photospheric velocity) seems to increase with time at early epochs, reaching values as high as 8000 km s$^{-1}$ around 15-20 days after maximum and then remains almost constant. The derived photospheric velocities, indicate a lower velocity for Type II SNe 1987A and 1999em as compared to SN Ic 1994I and SN IIb 1993J, while Type Ib events display a somewhat larger variation. The scatter, around day 20, is measured to be $\\sim$5000 km s$^{-1}$. Following two simple approaches, rough estimates of ejecta and hydrogen masses are given. A mass of hydrogen of approximately 0.02 $M_\\odot$ is obtained for SN 1990I, while SNe 1983N and 2000H ejected $\\sim$0.008 $M_\\odot$ and $\\sim$0.08 $M_\\odot$ of hydrogen, respectively. SN 1993J has a higher hydrogen mass, $\\sim 0.7$ $M_\\odot$ with a large uncertainty. A low mass and thin hydrogen layer with very high ejection velocities above the helium shell, is thus the most likely scenario for Type Ib SNe. Some interesting and curious issues relating to oxygen lines suggest future investigations.
On Measuring the Metallicity of Supernovae Type Ia Progenitors
Miles, Broxton J; Townsley, Dean M; Timmes, F X; Jackson, Aaron P; Calder, Alan C; Brown, Edward F
2015-01-01
In Type Ia Supernovae (\\sneia), the relative abundances of chemical elements are affected by the neutron excess in the composition of the progenitor white dwarf. Since these products leave signatures in the spectra near maximum light, spectral features may be used to constrain the composition of the progenitor. We calculate the nucleosynthetic yields for three \\snia simulations for a wide range of progenitor metallicities, and calculate synthetic light curves and spectra to explore correlations between progenitor metallicity and the strength of spectral features. We use two 2D simulations of the deflagration-detonation-transition scenario with different $^{56}$Ni yields and the W7 simulation to control for differences between explosion models and total yields. While the overall yields of intermediate mass elements (16 $<$ A $\\leq$ 40) differ between the three cases, trends in the yields are similar. With increasing metallicity, $^{28}$Si yields remain nearly constant, $^{40}$Ca yields decline, and Ti and $...
Dark fleshed varieties (Bing type) in regular type, light fleshed varieties (Rainier type and Royalton. For more information about these and other varieties, visit our web site at www
Wei, G.; Turner, W. D.; Claridge, D.; Liu, M.
2002-01-01
The supply air temperature set point for a singleduct constant air volume air handling unit (AHU) system is often reset based on either return air temperature or outside air temperature in order to reduce simultaneous cooling and heating energy...
Mellegard, K.D.; Pfeifle, T.W.
1999-07-01
A computerized, servohydraulic test system has been used in the laboratory to perform axisymmetric, triaxial compression tests on natural rock salt using a load path that maintains constant mean stress. The constant mean stress test protocol illustrates that modern test systems allow a nonstandard load path which can focus on a particular aspect of rock characterization; namely, the onset of dilation. Included are discussions of how the constant mean stress test could be used to investigate material anisotropy and determine elastic moduli. The results from the constant mean stress tests are compared to test results from a traditional test method. The paper also addresses system calibration concerns and the effects of pressure changes on the direct-contact extensometers used to measure strain.
Varghese, Joshua
2011-08-02
constant (TC) have been developed. The axial strain TC is a parameter that is related to the viscoelastic and poroelastic behavior of tissues. Estimation of this parameter can be done using curve fitting methods. However, the effect of temporal...
Browne, Michael
2010-07-14
. ................................................................... 26 Fig. 6. a)Entire Driveshaft Assembly, b) Constant Velocity Joint at PTU/Transaxle End of Driveshaft, c) Center Bearing Assembly with Non=Constant Velocity Joint, and d) Axle End of Driveshaft.... .......................................................... 36 Fig. 13. Order Comparison for a) 2nd Order, b) 4th Order, c) 6th Order, and d) 8th Order with Misalignment Angles of 0 (blue), 2(red), and 4 Degrees (magenta...
How precisely can we determine the pion-nucleon coupling constant from the isovector GMO sum rule?
B. Loiseau; T. E. O. Ericson; A. W. Thomas
2000-02-04
The isovector GMO sum rule for zero energy forward pion-nucleon scattering is critically studied to obtain the charged pion-nucleon coupling constant using the precise negatively charged pion-proton and pion-deuteron scattering lengths deduced recently from pionic atom experiments. This direct determination leads to a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09 (statistic) +- 0.17 (systematic). We obtain also accurate values for the pion-nucleon scattering lengths.
How Precisely can we Determine the $\\piNN$ Coupling Constant from the Isovector GMO Sum Rule?
Loiseau, B; Thomas, A W
1999-01-01
The isovector GMO sum rule for zero energy forward pion-nucleon scattering iscritically studied to obtain the charged pion-nucleon coupling constant usingthe precise negatively charged pion-proton and pion-deuteron scattering lengthsdeduced recently from pionic atom experiments. This direct determination leadsto a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09(statistic) +- 0.17 (systematic). We obtain also accurate values for thepion-nucleon scattering lengths.
Quantum Oscillator on $\\DC P^n$ in a constant magnetic field
Stefano Bellucci; Armen Nersessian; Armen Yeranyan
2004-06-22
We construct the quantum oscillator interacting with a constant magnetic field on complex projective spaces $\\DC P^N$, as well as on their non-compact counterparts, i. e. the $N-$dimensional Lobachewski spaces ${\\cal L}_N$. We find the spectrum of this system and the complete basis of wavefunctions. Surprisingly, the inclusion of a magnetic field does not yield any qualitative change in the energy spectrum. For $N>1$ the magnetic field does not break the superintegrability of the system, whereas for N=1 it preserves the exact solvability of the system. We extend this results to the cones constructed over $\\DC P^N$ and ${\\cal L}_N$, and perform the (Kustaanheimo-Stiefel) transformation of these systems to the three-dimensional Coulomb-like systems.
T. Thiemann
1999-10-04
We present here the canonical treatment of spherically symmetric (quantum) gravity coupled to spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate momenta, whose geometrical interpretation is explored. The dimension of the reduced phase space depends on the topology chosen, quite similar to the case of pure (2+1) gravity. We also compare the reduced phase space quantization to the algebraic quantization. Altogether, we observe that the present model serves as an interesting testing ground for full (3+1) gravity. We use the new canonical variables introduced by Ashtekar which simplifies the analysis tremendously.
T. Thiemann
1999-10-04
We extend here the canonical treatment of spherically symmetric (quantum) gravity to the most simple matter coupling, namely spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate momenta, whose geometrical interpretation is explored. The dimension of the reduced phase space depends on the topology chosen, quite similar to the case of pure (2+1) gravity. We investigate several conceptual and technical details that might be of interest for full (3+1) gravity. We use the new canonical variables introduced by Ashtekar, which simplifies the analysis tremendously.
Fundamental constants and their variability in theories of High Energy Physics
Thomas Dent
2008-02-12
The Standard Model of particle physics and the theory of General Relativity (GR) currently provide a good description of almost all phenomena of particle physics and gravitation that have received controlled experimental tests. However, the Standard Model contains many a priori variable parameters whose values, and whose apparent (near-)constancy, have yet to receive a convincing theoretical explanation. At the same time, GR may now require to be extended or altered at the largest length scales, to account for the recent apparent accelerated cosmological expansion. In this introductory review I present theoretical aspects of the search for explanations of the values and possible variations of fundamental ``constants'', focusing on the possibility of unification of interactions. I also relate cosmological variations to modifications of gravity both locally and cosmologically.
Cosmological constant in SUGRA models with Planck scale SUSY breaking and degenerate vacua
C. D. Froggatt; R. Nevzorov; H. B. Nielsen; A. W. Thomas
2014-10-08
The empirical mass of the Higgs boson suggests small to vanishing values of the quartic Higgs self--coupling and the corresponding beta function at the Planck scale, leading to degenerate vacua. This leads us to suggest that the measured value of the cosmological constant can originate from supergravity (SUGRA) models with degenerate vacua. This scenario is realised if there are at least three exactly degenerate vacua. In the first vacuum, associated with the physical one, local supersymmetry (SUSY) is broken near the Planck scale while the breakdown of the SU(2)_W\\times U(1)_Y symmetry takes place at the electroweak (EW) scale. In the second vacuum local SUSY breaking is induced by gaugino condensation at a scale which is just slightly lower than \\Lambda_{QCD} in the physical vacuum. Finally, in the third vacuum local SUSY and EW symmetry are broken near the Planck scale.
Decay constants $f_B$ and $f_{B_s}$ from HISQ simulations
Fermilab Lattice; MILC Collaborations; :; A. Bazavov; C. Bernard; C. Bouchard; N. Brown; C. DeTar; D. Du; A. X. El-Khadra; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. Komijani; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; C. Monahan; T. Primer; Heechang Na; E. T. Neil; J. N. Simone; R. L. Sugar; D. Toussaint; R. S. Van de Water; R. Zhou
2015-11-07
We give a progress report on a project aimed at a high-precision calculation of the decay constants $f_B$ and $f_{B_s}$ from simulations with HISQ heavy and light valence and sea quarks. Calculations are carried out with several heavy valence-quark masses on ensembles with 2+1+1 flavors of HISQ sea quarks at five lattice spacings and several light sea-quark mass ratios $m_{ud}/m_s$, including approximately physical sea-quark masses. This range of parameters provides excellent control of the continuum limit and of heavy-quark discretization errors. We present a preliminary error budget with projected uncertainties of 2.2~MeV and 1.5~MeV for $f_B$ and $f_{B_s}$, respectively.
Decay constants $f_B$ and $f_{B_s}$ from HISQ simulations
Lattice, Fermilab; Bazavov, A; Bernard, C; Bouchard, C; Brown, N; DeTar, C; Du, D; El-Khadra, A X; Freeland, E D; Gámiz, E; Gottlieb, Steven; Heller, U M; Komijani, J; Kronfeld, A S; Laiho, J; Levkova, L; Mackenzie, P B; Monahan, C; Primer, T; Na, Heechang; Neil, E T; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R
2015-01-01
We give a progress report on a project aimed at a high-precision calculation of the decay constants $f_B$ and $f_{B_s}$ from simulations with HISQ heavy and light valence and sea quarks. Calculations are carried out with several heavy valence-quark masses on ensembles with 2+1+1 flavors of HISQ sea quarks at five lattice spacings and several light sea-quark mass ratios $m_{ud}/m_s$, including approximately physical sea-quark masses. This range of parameters provides excellent control of the continuum limit and of heavy-quark discretization errors. We present a preliminary error budget with projected uncertainties of 2.2~MeV and 1.5~MeV for $f_B$ and $f_{B_s}$, respectively.
R. Yarmukhamedov; D. Baye
2011-02-08
Explicit relations between the effective-range expansion and the nuclear vertex constant or asymptotic normalization coefficient (ANC) for the virtual decay $B\\to A+a$ are derived for an arbitrary orbital momentum together with the corresponding location condition for the ($A+a$) bound-state energy. They are valid both for the charged case and for the neutral case. Combining these relations with the standard effective-range function up to order six makes it possible to reduce to two the number of free effective-range parameters if an ANC value is known from experiment. Values for the scattering length, effective range, and form parameter are determined in this way for the $^{16}$O+$p$, $\\alpha+t$ and $\\alpha+^3$He collisions in partial waves where a bound state exists by using available ANCs deduced from experiments. The resulting effective-range expansions for these collisions are valid up to energies larger 5 MeV.
Running coupling constant from lattice studies of gluon and ghost propagators
Cucchieri, A.; Mendes, T.
2004-12-02
We present a numerical study of the running coupling constant in four-dimensional pure-SU(2) lattice gauge theory. The running coupling is evaluated by fitting data for the gluon and ghost propagators in minimal Landau gauge. Following Refs. [1, 2], the fitting formulae are obtained by a simultaneous integration of the {beta} function and of a function coinciding with the anomalous dimension of the propagator in the momentum subtraction scheme. We consider these formulae at three and four loops. The fitting method works well, especially for the ghost case, for which statistical error and hyper-cubic effects are very small. Our present result for {lambda}MS is 200{sub -40}{sup +60} MeV, where the error is purely systematic. We are currently extending this analysis to five loops in order to reduce this systematic error.
On solutions of the 2D Navier-Stokes equations with constant energy and enstrophy
Jing Tian; Bingsheng Zhang
2015-07-04
It is not yet known if the global attractor of the space periodic 2D Navier-Stokes equations contains nonstationary solutions $u(x,t)$ such that their energy and enstrophy per unit mass are constant for every $t \\in (-\\infty, \\infty)$. The study of the properties of such solutions was initiated in \\cite{CMM13}, where, due to the hypothetical existence of such solutions, they were called "ghost solutions". In this work, we introduce and study geometric structures shared by all ghost solutions. This study led us to consider a subclass of ghost solutions for which those geometric structures have a supplementary stability property. In particular, we show that the wave vectors of the active modes of this subclass of ghost solutions must satisfy certain supplementary constraints. We also found a computational way to check for the existence of these ghost solutions.
Stochastic dynamics of adhesion clusters under shared constant force and with rebinding
T. Erdmann; U. S. Schwarz
2004-05-12
Single receptor-ligand bonds have finite lifetimes, so that biological systems can dynamically react to changes in their environment. In cell adhesion, adhesion bonds usually act cooperatively in adhesion clusters. Outside the cellular context, adhesion clusters can be probed quantitatively by attaching receptors and ligands to opposing surfaces. Here we present a detailed theoretical analysis of the stochastic dynamics of a cluster of parallel bonds under shared constant loading and with rebinding. Analytical solutions for the appropriate one-step master equation are presented for special cases, while the general case is treated with exact stochastic simulations. If the completely dissociated state is modeled as an absorbing boundary, mean cluster lifetime is finite and can be calculated exactly. We also present a detailed analysis of fluctuation effects and discuss various approximations to the full stochastic description.
Soil damping constants related to common soil properties in sands and clays
Gibson, Gary Clive
1968-01-01
SOIL D'c~. 'I'IIIG COESTAlxI. S PI', IslTED TO CO!~i'iOI& SOII. PRO& ERTIES J3I SAE1)S AND CL?"S A Thesis by Gary Olive G'boon Sr b':I' te'I to tho Gra=lu. . te Col lope of Texas Afxl Univcrsi ty in pert'al fulfillsent of the requirenent... for the Je;, ree of YiASTER Ol" SCIEI!CE August ISSS II. ';or Subject: Civil I:nSin er. nb SOIL DAMPING CONSTANTS REIATED TO COMMON SOIL PROPERTIES IN SANDS AND CLAYS A Thesis by Gary Clive Gibson Approved as to style and content by: (Head...
Measured dose rate constant from oncology patients administered 18F for positron emission tomography
Quinn, Brian; Holahan, Brian; Aime, Jean; Humm, John; St Germain, Jean; Dauer, Lawrence T.
2012-10-15
Purpose: Patient exposure rate measurements verify published patient dose rate data and characterize dose rates near 2-18-fluorodeoxyglucose ({sup 18}F-FDG) patients. A specific dose rate constant based on patient exposure rate measurements is a convenient quantity that can be applied to the desired distance, injection activity, and time postinjection to obtain an accurate calculation of cumulative external radiation dose. This study reports exposure rates measured at various locations near positron emission tomography (PET) {sup 18}F-FDG patients prior to PET scanning. These measurements are normalized for the amount of administered activity, measurement distance, and time postinjection and are compared with other published data. Methods: Exposure rates were measured using a calibrated ionization chamber at various body locations from 152 adult oncology patients postvoid after a mean uptake time of 76 min following injection with a mean activity of 490 MBq {sup 18}F-FDG. Data were obtained at nine measurement locations for each patient: three near the head, four near the chest, and two near the feet. Results: On contact with, 30 cm superior to and 30 cm lateral to the head, the mean (75th percentile) dose rates per unit injected activity at 60 min postinjection were 0.482 (0.511), 0.135 (0.155), and 0.193 (0.223) {mu}Sv/MBq h, respectively. On contact with, 30 cm anterior to, 30 cm lateral to and 1 m anterior to the chest, the mean (75th percentile) dose rates per unit injected activity at 60 min postinjection were 0.623 (0.709), 0.254 (0.283), 0.190 (0.218), and 0.067 (0.081) {mu}Sv/MBq h respectively. 30 cm inferior and 30 cm lateral to the feet, the mean (75th percentile) dose rates per unit injected activity at 60 min postinjection were 0.024 (0.022) and 0.039 (0.044) {mu}Sv/MBq h, respectively. Conclusions: The measurements for this study support the use of 0.092 {mu}Sv m{sup 2}/MBq h as a reasonable representation of the dose rate anterior from the chest of patients immediately following injection. This value can then be reliably scaled to the desired time and distance for planning and staff dose evaluation purposes. At distances closer than 1 m, a distance-specific dose rate constant of 0.367 {mu}Sv/MBq h at 30 cm is recommended for accurate calculations. An accurate patient-specific dose rate constant that accounts for patient-specific variables (e.g., distribution and attenuation) will allow an accurate evaluation of the dose rate from a patient injected with an isotope rather than simply utilizing a physical constant.
Cosmological Non-Constant Problem: Cosmological bounds on TeV-scale physics and beyond
Niayesh Afshordi; Elliot Nelson
2015-07-04
We study the influence of the fluctuations of a Lorentz invariant and conserved vacuum on cosmological metric perturbations, and show that they generically blow up in the IR. We compute this effect using the K\\"all\\'en-Lehmann spectral representation of stress correlators in generic quantum field theories, as well as the holographic bound on their entanglement entropy, both leading to an IR cut-off that scales as the fifth power of the highest UV scale (in Planck units). One may view this as analogous to the Heisenberg uncertainty principle, which is imposed on the phase space of gravitational theories by the Einstein constraint equations. The leading effect on cosmological observables come from anisotropic vacuum stresses which imply: i) any extension of the standard model of particle physics can only have masses (or resonances) $\\lesssim$ 35 TeV, and ii) perturbative quantum field theory or quantum gravity becomes strongly coupled beyond a cut-off scale of $\\Lambda\\lesssim1$ PeV. Such a low cut-off is independently motivated by the Higgs hierarchy problem. This result, which we dub the cosmological non-constant problem, can be viewed as an extension of the cosmological constant (CC) problem, demonstrating the non-trivial UV-IR coupling and (yet another) limitation of effective field theory in gravity. However, it is more severe than the old CC problem, as vacuum fluctuations cannot be tuned to cancel due to the positivity of spectral densities or entropy. We thus predict that future advances in cosmological observations and collider technology will sandwich from above and below, and eventually discover, new (non-perturbative) physics beyond the Standard Model within the TeV-PeV energy range.
Effects of swirl-flow on flame propagation in a constant-volume vessel
Cai, P.; Watanabe, Kazunori; Obara, Tetsuro; Yoshihashi, Teruo; Ohyagi, Shigeharu
1999-07-01
Flame propagation in a closed vessel is one of the fundamental topics in the combustion science and technology. This problem has been studied mostly for application to engine combustion because the combustion processes in a premixed spark ignition engine are well simulated by those processes in a constant-volume combustion chamber. One of the most important objective to study this phenomena is to elucidate the combustion phenomena to increase the thermal efficiency of engine by enhancing the combustion process. In real engines, a number of technical methods such as swirl, tumble, squish and jet flows ere developed to shorten a burning time. All of these methods make use of flows in the combustion chamber. The fundamental problem is then to elucidate a mechanism of reduction of the burning time by the flows and their turbulence. In the present work, experiments were conducted to investigate the effects of swirl-flow on the flame propagation in a disc-shaped constant-volume vessel of 100 mm in diameter and 30 mm in depth. Figure A-1 shows a schematic of the apparatus. Gaseous mixtures used were methane diluted with air at an atmospheric pressure, and their equivalence ratios were varied as a parameter. Ignition timing was varied to change the velocity of swirling flow before the flame propagation. As results, a burning time was found to be decreased as the swirling flow increased and a maximum pressure was increased as the velocity increased as a total heat loss decreased. Flame front structures were clearly observed by the instantaneous schlieren photography.
Types of JavaO Types: Types A, B, C are
Börger, Egon
.Meth(Exps) | super.Meth(Exps) Copyright c 2002 Robert F. St¨ark, Computer Science Department, ETH Z[ ] Serializable. If A B and A, B are reference types, then A[ ] B[ ]. Copyright c 2002 Robert F. St¨ark, Computer not equal (references) Copyright c 2002 Robert F. St¨ark, Computer Science Department, ETH Z
Operational Semantics and Polymorphic Type Inference
Tofte, Mads
1988-01-01
Three languages with polymorphic type disciplines are discussed, namely the ?-calculus with Milner's polymorphic type discipline; a language with imperative features (polymorphic references); and a skeletal module language ...
Tridiagonal pairs of Krawtchouk type
Ito, Tatsuro
2007-01-01
Let $K$ denote an algebraically closed field with characteristic 0 and let $V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$ denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has Krawtchouk type whenever the sequence $\\lbrace d-2i\\rbrace_{i=0}^d$ is a standard ordering of the eigenvalues of $A$ and a standard ordering of the eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there exists a nondegenerate symmetric bilinear form $$ on $V$ such that $= $ and $= $ for $u,v\\in V$. We show that the following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii) $A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.
Improved source design for p-type tunnel field-effect transistors: Towards truly complementary logic
Verreck, Devin Groeseneken, Guido; Verhulst, Anne S.; Collaert, Nadine; Mocuta, Anda; Thean, Aaron; Sorée, Bart
2014-12-15
Complementary logic based on tunnel field-effect transistors (TFETs) would drastically reduce power consumption thanks to the TFET's potential to obtain a sub-60?mV/dec subthreshold swing (SS). However, p-type TFETs typically do not meet the performance of n-TFETs for direct bandgap III-V configurations. The p-TFET SS stays well above 60?mV/dec, due to the low density of states in the conduction band. We therefore propose a source configuration in which a highly doped region is maintained only near the tunnel junction. In the remaining part of the source, the hot carriers in the exponential tail of the Fermi-Dirac distribution are blocked by reducing the doping degeneracy, either with a source section with a lower doping concentration or with a heterostructure. We apply this concept to n-p-i-p configurations consisting of In{sub 0.53}Ga{sub 0.47}As and an InP-InAs heterostructure. 15-band quantum mechanical simulations predict that the configurations with our source design can obtain sub-60?mV/dec SS, with an on-current comparable to the conventional source design.
Type Ia Supernovae: Spectroscopic Surprises
David Branch
2003-10-23
Recent observations have extended the range of diversity among spectra of Type Ia supernovae. I briefly discuss SN Ia explosion models in the spectroscopic context, the observed diversity, and some recent results from direct analysis with the Synow code for one normal and two peculiar SNe Ia. Relating the observational manifestations of diversity to their physical causes is looking like an ever more challenging problem.
Measuring Boltzmann's constant with a low-cost atomic force microscope: An undergraduate experiment
Manalis, Scott
to directly control it. Its pedagogical advantage is that students interact with a complete instrument system measurements, students learn to apply numerous concepts such as digital sampling, Fourier-domain analysis designed and built an inexpen- sive atomic force microscope AFM system that enables this type of hands
Fact #586: August 31, 2009 New Vehicle Fuel Economies by Vehicle Type
Broader source: Energy.gov [DOE]
The average fuel economy for new cars climbed to over 30 miles per gallon (mpg) in 2008 while the average for new pickup trucks stayed around 20 mpg. For new vans and sport utility vehicles (SUVs)...
Kim, B.R.; Kalis, E.M.; DeWulf, T.; Andrews, K.M.
2000-02-01
This paper describes experimental results of equilibrium partitioning of several significant paint solvents and formaldehyde between air and water to quantify the potential for capturing and retaining the constituents in spraybooth scrubber water during automotive painting. The compounds studied are toluene, n-butanol, methyl ethyl ketone methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, and n-methyl-2-pyrrolidinone. A set of field data collected at a Ford Motor Company assembly plant was also analyzed to determine whether data were consistent with the equilibrium phenomenon. The primary findings include: (a) There were more than six orders of magnitude difference in the Henry's law constants among the solvents studied. A solvent with a smaller constant is less easily stripped from water. The Henry's law constants decrease in the following order: toluene and xylenes > methyl ethyl ketone > n-butanol > butyl cellosolve acetate > butyl cellosolve > formaldehyde > butyl carbitol > n-methyl-2-pyrrolidinone. (b) Field data showed accumulation of n-methyl-2-pyrrolidinone and stable concentrations of butyl carbitol, butyl cellosolve, and n-butanol in the paint-sludge pit water during a 2-month period. Stable concentrations indicate a continuous, balanced capture and stripping of the solvents. Data were consistent with measured Henry's law constants. (c) The low Henry's law constant for formaldehyde is the result of the fact that it is hydrated when dissolved in water.
Wheel-type magnetic refrigerator
Barclay, J.A.
1982-01-20
The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.
Wheel-type magnetic refrigerator
Barclay, J.A.
1983-10-11
The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.
Window Types | Department of Energy
Office of Environmental Management (EM)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann Jackson About1996HowFOAShowingFuelWeatherize Â» AirareAbout Key ActivitiesWindow Types
Window Types | 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: Alternative FuelsofProgram: Report1538-1950DepartmentWaveWind Program R&DResearchWindow Types
NASA's astonishing evidence that c is not constant: The pioneer anomaly
E. D. Greaves
2007-01-11
For over 20 years NASA has struggled to find an explanation to the Pioneer anomaly. Now it becomes clear the solution to the riddle is that they have uncovered evidence that c, the speed of light, is not quite a universal constant. Using J. C. Cure s hypothesis that the index of refraction is a function of the gravitational energy density of space and straightforward Newtonian mechanics, NASA s measurements provide compelling evidence that the speed of light depends on the inverse of the square root of the gravitational energy density of space. The magnitude of the Pioneer anomalous acceleration leads to the value of the primordial energy density of space due to faraway stars and galaxies: 1.0838. x 10^15 Joule/m3. A value which almost miraculously coincides with the same quantity: 1.09429 x 10^15 Joule/m3 derived by J. C. Cure from a completely different phenomenon: the bending of starlight during solar eclipses.
Krajina, Brad A.; Kocherlakota, Lakshmi S.; Overney, René M., E-mail: roverney@u.washington.edu [Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750 (United States)
2014-10-28
The energetics involved in the bonding fluctuations between nanometer-sized silicon dioxide (SiO{sub 2}) probes and highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS{sub 2}) could be quantified directly and locally on the submicron scale via a time-temperature superposition analysis of the lateral forces between scanning force microscopy silicon dioxide probes and inorganic sample surfaces. The so-called “intrinsic friction analysis” (IFA) provided direct access to the Hamaker constants for HOPG and MoS{sub 2}, as well as the control sample, calcium fluoride (CaF{sub 2}). The use of scanning probe enables nanoscopic analysis of bonding fluctuations, thereby overcoming challenges associated with larger scale inhomogeneity and surface roughness common to conventional techniques used to determine surface free energies and dielectric properties. A complementary numerical analysis based on optical and electron energy loss spectroscopy and the Lifshitz quantum electrodynamic theory of van der Waals interactions is provided and confirms quantitatively the IFA results.
Diffraction Profiles of Elasticity Bent Single Crystals with Constant Strain Gradients
Yan,H.; Kalenci, O.; Noyan, I.
2007-01-01
This work presents a set of equations that can be used to predict the dynamical diffraction profile from a non-transparent single crystal with a constant strain gradient examined in Bragg reflection geometry with a spherical incident X-ray beam. In agreement with previous work, the present analysis predicts two peaks: a primary diffraction peak, which would have still been observed in the absence of the strain gradient and which exits the specimen surface at the intersection point of the incident beam with the sample surface, and a secondary (mirage) peak, caused by the deflection of the wavefield within the material, which exits the specimen surface further from this intersection point. The integrated intensity of the mirage peak increases with increasing strain gradient, while its separation from the primary reflection peak decreases. The directions of the rays forming the mirage peak are parallel to those forming the primary diffraction peak. However, their spatial displacement might cause (fictitious) angular shifts in diffractometers equipped with area detectors or slit optics. The analysis results are compared with experimental data from an Si single-crystal strip bent in cantilever configuration, and the implications of the mirage peak for Laue analysis and high-precision diffraction measurements are discussed.
Impact of instrumental systematic errors on fine-structure constant measurements with quasar spectra
J. B. Whitmore; M. T. Murphy
2014-11-18
We present a new `supercalibration' technique for measuring systematic distortions in the wavelength scales of high resolution spectrographs. By comparing spectra of `solar twin' stars or asteroids with a reference laboratory solar spectrum, distortions in the standard thorium--argon calibration can be tracked with $\\sim$10 m s$^{-1}$ precision over the entire optical wavelength range on scales of both echelle orders ($\\sim$50--100 \\AA) and entire spectrographs arms ($\\sim$1000--3000 \\AA). Using archival spectra from the past 20 years we have probed the supercalibration history of the VLT--UVES and Keck--HIRES spectrographs. We find that systematic errors in their wavelength scales are ubiquitous and substantial, with long-range distortions varying between typically $\\pm$200 m s$^{-1}$ per 1000 \\AA. We apply a simple model of these distortions to simulated spectra that characterize the large UVES and HIRES quasar samples which previously indicated possible evidence for cosmological variations in the fine-structure constant, $\\alpha$. The spurious deviations in $\\alpha$ produced by the model closely match important aspects of the VLT--UVES quasar results at all redshifts and partially explain the HIRES results, though not self-consistently at all redshifts. That is, the apparent ubiquity, size and general characteristics of the distortions are capable of significantly weakening the evidence for variations in $\\alpha$ from quasar absorption lines.
Limits on Variations in Fundamental Constants from 21-cm and Ultraviolet Quasar Absorption Lines
Tzanavaris, P.; Webb, J.K.; Flambaum, V.V.; Curran, S.J.; Murphy, M.T.
2005-07-22
Quasar absorption spectra at 21-cm and UV rest wavelengths are used to estimate the time variation of x{identical_to}{alpha}{sup 2}g{sub p}{mu}, where {alpha} is the fine structure constant, g{sub p} the proton g factor, and m{sub e}/m{sub p}{identical_to}{mu} the electron/proton mass ratio. Over a redshift range 0.24 < or approx. z{sub abs} < or approx. 2.04, <{delta}x/x>{sub total}{sup weighted}=(1.17{+-}1.01)x10{sup -5}. A linear fit gives x/x=(-1.43{+-}1.27)x10{sup -15} yr{sup -1}. Two previous results on varying {alpha} yield the strong limits {delta}{mu}/{mu}=(2.31{+-}1.03)x10{sup -5} and {delta}{mu}/{mu}=(1.29{+-}1.01)x10{sup -5}. Our sample, 8x larger than any previous, provides the first direct estimate of the intrinsic 21-cm and UV velocity differences {approx}6 km s{sup -1}.
Emerging the dark sector from thermodynamics of cosmological systems with constant pressure
Alejandro Aviles; Norman Cruz; Jaime Klapp; Orlando Luongo
2014-12-13
We investigate the thermodynamics of general fluids that have the constriction that their pressure is constant. For example, this happens in the case of pure dust matter, for which the pressure vanishes and also in the case of standard dark matter phenomenology. Assuming a finite non-zero pressure, the corresponding dynamics is richer than one naively would expect. In particular, it can be considered as a unified description of dark energy and dark matter. We first consider the more general thermodynamic properties of this class of fluids finding the important result that for them adiabatic and isothermal processes should coincide. We therefore study their behaviors in curved space-times where local thermal equilibrium can be appealed. Thus, we show that this dark fluid degenerates with the dark sector of the LCDM model only in the case of adiabatic evolution. We demonstrate that, adding dissipative processes, a phantom behavior can occur and finally we further highlight that an arbitrary decomposition of the dark sector, into ad hoc dark matter and dark energy terms, may give rise to phantom dark energy, whereas the whole dark sector remains non-phantom.
Bound on the variation in the fine structure constant implied by Oklo data
Hamdan, Leila
2015-01-01
Dynamical models of dark energy can imply that the fine structure constant $\\alpha$ varies over cosmological time scales. Data on shifts in resonance energies $E_r$ from the Oklo natural fission reactor have been used to place restrictive bounds on the change in $\\alpha$ over the last 1.8 billion years. We review the uncertainties in these analyses, focussing on corrections to the standard estimate of $k_\\alpha\\!=\\!\\alpha\\,dE_r/d\\alpha$ due to Damour and Dyson. Guided, in part, by the best practice for assessing systematic errors in theoretical estimates spelt out by Dobaczewski et al. [in J. Phys. G: Nucl. Part. Phys. 41, 074001 (2014)], we compute these corrections in a variety of models tuned to reproduce existing nuclear data. Although the net correction is uncertain to within a factor of 2 or 3, it constitutes at most no more than 25% of the Damour-Dyson estimate of $k_\\alpha$. Making similar allowances for the uncertainties in the modeling of the operation of the Oklo reactors, we conclude that the rela...
Bohr - Planck quantum theory, (Tesla) magnetic monopoles and fine structure constant
Vladan Pankovic; Darko V. Kapor; Stevica Djurovic; Miodrag Krmar
2014-10-17
In this work we apply Bohr-Planck (Old quantum atomic and radiation) theory, i.e. and quasi-classical methods for analysis of the magnetic monopoles and other problems. We reproduce exactly some basic elements of the Dirac magnetic monopoles theory, especially Dirac electric/magnetic charge quantization condition. Also, we suggest a new, effective, simply called Tesla model (for analogy with positions of the solenoids by Tesla inductive motor) of the magnetic monopole instead of usual effective Dirac model (half-infinite, very tinny solenoid) of the magnetic monopole. In our, i.e. Tesla model we use three equivalent tiny solenoids connected in series with a voltage source. One end of any solenoid is placed at the circumference of a circle and solenoids are directed radial toward circle center. Length of any solenoid is a bit smaller than finite circle radius so that other end of any solenoid is very close to the circle center. Angles between neighboring solenoids equal $120^{\\circ}$. All this implies that, practically, there is no magnetic field, or, magnetic pole, e.g. $S$, in the circle center, and that whole system holds only other, $N$ magnetic pole, at the ends of the solenoids at circle circumference. Finally, we reproduce relatively satisfactory value of the fine structure constant using Planck, i.e. Bose-Einstein statistics and Wien displacement law.
Perspective: Tipping the scales: Search for drifting constants from molecular spectra
Jansen, Paul; Bethlem, Hendrick L.; Ubachs, Wim [Department of Physics and Astronomy, LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)] [Department of Physics and Astronomy, LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)
2014-01-07
Transitions in atoms and molecules provide an ideal test ground for constraining or detecting a possible variation of the fundamental constants of nature. In this perspective, we review molecular species that are of specific interest in the search for a drifting proton-to-electron mass ratio ?. In particular, we outline the procedures that are used to calculate the sensitivity coefficients for transitions in these molecules and discuss current searches. These methods have led to a rate of change in ? bounded to 6 × 10{sup ?14}/yr from a laboratory experiment performed in the present epoch. On a cosmological time scale, the variation is limited to |??/?| < 10{sup ?5} for look-back times of 10–12× 10{sup 9} years and to |??/?| < 10{sup ?7} for look-back times of 7× 10{sup 9} years. The last result, obtained from high-redshift observation of methanol, translates into ?{sup .}/?=(1.4±1.4)×10{sup ?17}/yr if a linear rate of change is assumed.
The Constant-Sound-Speed parameterization for NJL models of quark matter in hybrid stars
Ranea-Sandoval, Ignacio F; Orsaria, Milva G; Contrera, Gustavo A; Weber, Fridolin; Alford, Mark G
2016-01-01
The discovery of pulsars as heavy as 2 solar masses has led astrophysicists to rethink the core compositions of neutron stars, ruling out many models for the nuclear equations of state (EoS). We explore the hybrid stars that occur when hadronic matter is treated in a relativistic mean-field approximation and quark matter is modeled by three-flavor local and non-local Nambu Jona-Lasinio (NJL) models with repulsive vector interactions. The NJL models typically yield equations of state that feature a first order transition to quark matter. Assuming that the quark-hadron surface tension is high enough to disfavour mixed phases, and restricting to EoSes that allow stars to reach 2 solar masses, we find that the appearance of the quark matter core either destabilizes the star immediately (this is typical for non-local NJL models) or leads to a very short hybrid star branch in the mass-radius relation (this is typical for local NJL models). Using the Constant-Sound-Speed parametrization we can see that the reason fo...
Peter K. Relich; Mark J. Olah; Patrick J. Cutler; Keith A. Lidke
2015-08-21
The movement of a particle described by Brownian motion is quantified by a single parameter, $D$, the diffusion constant. The estimation of $D$ from a discrete sequence of noisy observations is a fundamental problem in biological single particle tracking experiments since it can report on the environment and/or the state of the particle itself via hydrodynamic radius. Here we present a method to estimate $D$ that takes into account several effects that occur in practice, that are important for correct estimation of $D$, and that have hitherto not been combined together for estimation of $D$. These effects are motion blur from finite integration time of the camera, intermittent trajectories, and time-dependent localization uncertainty. Our estimation procedure, a maximum likelihood estimation, follows directly from the likelihood expression for a discretely observed Brownian trajectory that explicitly includes these effects. The manuscript begins with the formulation of the likelihood expression and then presents three methods to find the exact solution. Each method has its own advantages in either computational robustness, theoretical insight, or the estimation of hidden variables. We then compare our estimator to previously published estimators using a squared log loss function to demonstrate the benefit of including these effects.
Fractal universe and the speed of light: Revision of the universal constants
Antonio Alfonso-Faus
2009-05-25
We apply the property of selfsimilarity that corresponds to the concept of a fractal universe, to the dimension of time. It follows that any interval of time, given by any tick of any clock, is proportional to the age of the universe. The fractality of time gives the fractality of space and mass. First consequence is that the speed of light decreases inversely proportional to time, same as the Hubble parameter. We then revise the universal constants and, at the cosmological scale, they are all of order one, as Dirac proposed. We find three different scales, each one separated by a factor of about 5x10^60: the universe, the Planck scale and what we call the sub Planck scale. Integration of the Einstein cosmological equations, for this fractal universe, gives the solution of a non-expanding universe with the present value of the observed numerical parameters. The red shift measured from the distant galaxies is interpreted here as due to the decreasing speed of light in a fractal universe.
Subodha Mishra
2007-06-13
Considering our expanding universe as made up of gravitationally interacting particles which describe particles of luminous matter and dark matter and dark energy which is described by a repulsive harmonic potential among the points in the flat 3-space, we derive a quantum mechanical relation connecting, temperature of the cosmic microwave background radiation, age, and cosmological constant of the universe. When the cosmological constant is zero, we get back the Gamow's relation with a much better coefficient. Otherwise, our theory predicts a value of the cosmological constant $2.0 10^{-56} {\\rm {cm^{-2}}}$ when the present values of cosmic microwave background temperature of 2.728 K and age of the universe 14 billion years are taken as input.
The Bianchi type-V Dark Energy Cosmology in Self Interacting Brans Dicke Theory of Gravity
Singh, J K
2016-01-01
This paper deals with a spatially homogeneous and totally anisotropic Bianchi type-V cosmological model within the framework of self interacting Brans Dicke theory of gravity in the background of anisotropic dark energy (DE) with variable equation of state (EoS) parameter and constant deceleration parameter. Constant deceleration parameter leads to two models of universe, i.e. power law model and exponential model. EoS parameter {\\omega} and its existing range for the models is in good agreement with the most recent observational data. We notice that {\\omega} given by (37) i.e {\\omega}(t) = log(k1t) is more suitable in explaining the evolution of the universe. The physical behaviors of the solutions have also been discussed using some physical quantities. Finally, we observe that despite having several prominent features, both of the DE models discussed fail in details.
H. -G. Ludwig; F. Allard; P. H. Hauschildt
2006-08-12
We constructed hydrodynamical model atmospheres for mid M-type main-, as well as pre-main-sequence (PMS) objects. Despite the complex chemistry encountered in these cool atmospheres a reasonably accurate representation of the radiative transfer is possible, even in the context of time-dependent and three-dimensional models. The models provide detailed information about the morphology of M-type granulation and statistical properties of the convective surface flows. In particular, we determined the efficiency of the convective energy transport, and the efficiency of mixing by convective overshoot. The convective transport efficiency was expressed in terms of an equivalent mixing-length parameter alpha in the formulation of mixing-length theory (MLT) given by Mihalas (1978). Alpha amounts to values around 2 for matching the entropy of the deep, adiabatically stratified regions of the convective envelope, and lies between 2.5 and 3.0 for matching the thermal structure of the deep photosphere. For current spectral analysis of PMS objects this implies that MLT models based on alpha=2.0 overestimate the effective temperature by 100 K and surface gravities by 0.25 dex. The average thermal structure of the formally convectively stable layers is little affected by convective overshoot and wave heating, i.e., stays close to radiative equilibrium conditions. Our models suggest that the rate of mixing by convective overshoot declines exponentially with geometrical distance to the Schwarzschild stability boundary. It increases at given effective temperature with decreasing gravitational acceleration.
Deflagrations in hybrid CONe white dwarfs: a route to explain the faint Type Iax supernova 2008ha
Kromer, M; Pakmor, R; Ruiter, A J; Hillebrandt, W; Marquardt, K S; Roepke, F K; Seitenzahl, I R; Sim, S A; Taubenberger, S
2015-01-01
Stellar evolution models predict the existence of hybrid white dwarfs (WDs) with a carbon-oxygen core surrounded by an oxygen-neon mantle. Being born with masses ~1.1 Msun, hybrid WDs in a binary system may easily approach the Chandrasekhar mass (MCh) by accretion and give rise to a thermonuclear explosion. Here, we investigate an off-centre deflagration in a near-MCh hybrid WD under the assumption that nuclear burning only occurs in carbon-rich material. Performing hydrodynamics simulations of the explosion and detailed nucleosynthesis post-processing calculations, we find that only 0.014 Msun of material is ejected while the remainder of the mass stays bound. The ejecta consist predominantly of iron-group elements, O, C, Si and S. We also calculate synthetic observables for our model and find reasonable agreement with the faint Type Iax SN 2008ha. This shows for the first time that deflagrations in near-MCh WDs can in principle explain the observed diversity of Type Iax supernovae. Leaving behind a near-MCh...
Hydrogen in Type Ic Supernovae?
David Branch; David J. Jeffery; Timothy R. Young; E. Baron
2006-05-09
By definition, a Type Ic supernova (SN Ic) does not have conspicuous lines of hydrogen or helium in its optical spectrum. SNe Ic usually are modelled in terms of the gravitational collapse of bare carbon-oxygen cores. We consider the possibility that the spectra of ordinary (SN 1994I-like) SNe Ic have been misinterpreted, and that SNe Ic eject hydrogen. An absorption feature usually attributed to a blend of Si II 6355 and C II 6580 may be produced by H-alpha. If SN 1994I-like SNe Ic eject hydrogen, the possibility that hypernova (SN 1998bw-like) SNe Ic, some of which are associated with gamma-ray bursts, also eject hydrogen should be considered. The implications of hydrogen for SN Ic progenitors and explosion models are briefly discussed.
Michael, Scott; Steiman-Cameron, Thomas Y.; Durisen, Richard H. [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Boley, Aaron C., E-mail: scamicha@astro.indiana.edu, E-mail: tomsc@astro.indiana.edu, E-mail: durisen@astro.indiana.edu, E-mail: aaron.boley@gmail.com [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
2012-02-10
We conduct a convergence study of a protostellar disk, subject to a constant global cooling time and susceptible to gravitational instabilities (GIs), at a time when heating and cooling are roughly balanced. Our goal is to determine the gravitational torques produced by GIs, the level to which transport can be represented by a simple {alpha}-disk formulation, and to examine fragmentation criteria. Four simulations are conducted, identical except for the number of azimuthal computational grid points used. A Fourier decomposition of non-axisymmetric density structures in cos (m{phi}), sin (m{phi}) is performed to evaluate the amplitudes A{sub m} of these structures. The A{sub m} , gravitational torques, and the effective Shakura and Sunyaev {alpha} arising from gravitational stresses are determined for each resolution. We find nonzero A{sub m} for all m-values and that A{sub m} summed over all m is essentially independent of resolution. Because the number of measurable m-values is limited to half the number of azimuthal grid points, higher-resolution simulations have a larger fraction of their total amplitude in higher-order structures. These structures act more locally than lower-order structures. Therefore, as the resolution increases the total gravitational stress decreases as well, leading higher-resolution simulations to experience weaker average gravitational torques than lower-resolution simulations. The effective {alpha} also depends upon the magnitude of the stresses, thus {alpha}{sub eff} also decreases with increasing resolution. Our converged {alpha}{sub eff} is consistent with predictions from an analytic local theory for thin disks by Gammie, but only over many dynamic times when averaged over a substantial volume of the disk.
Translational Symmetry Breaking in Higgs & Gauge Theory, and the Cosmological Constant
Nick Evans; Tim R. Morris; Marc Scott
2015-07-10
We argue, at a very basic effective field theory level, that higher dimension operators in scalar theories that break symmetries at scales close to their ultraviolet completion cutoff, include terms that favour the breaking of translation (Lorentz) invariance, potentially resulting in striped, chequered board or general crystal-like phases. Such descriptions can be thought of as the effective low energy description of QCD-like gauge theories near their strong coupling scale where terms involving higher dimension operators are generated. Our low energy theory consists of scalar fields describing operators such as $\\bar{q} q$ and $\\bar{q} F^{(2n)} q$. Such scalars can have kinetic mixing terms that generate effective momentum dependent contributions to the mass matrix. We show that these can destabilize the translationally invariant vacuum. It is possible that in some real gauge theory such operators could become sufficiently dominant to realize such phases and it would be interesting to look for them in lattice simulations. We present a holographic model of the same phenomena which includes RG running. A key phenomenological motive to look at such states is recent work that shows that the non-linear response in $R^2$ gravity to such short range fluctuations can mimic a cosmological constant. Intriguingly in a cosmology with such a Starobinsky inflation term, to generate the observed value of the present day acceleration would require stripes at the electroweak scale. Unfortunately, low energy phenomenological constraints on Lorentz violation in the electron-photon system appear to strongly rule out any such possibility outside of a disconnected dark sector.
Lunt, A. J. G. Xie, M. Y.; Baimpas, N.; Korsunsky, A. M.; Zhang, S. Y.; Kabra, S.; Kelleher, J.; Neo, T. K.
2014-08-07
Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11?=?451, C33?=?302, C44?=?39, C66?=?82, C12?=?240, and C13?=?50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.
Disk Accretion Flow Driven by Large-Scale Magnetic Fields: Solutions with Constant Specific Energy
Li-Xin Li
2003-05-29
(Abridged) We study the dynamical evolution of a stationary, axisymmetric, and perfectly conducting cold accretion disk containing a large-scale magnetic field around a Kerr black hole, trying to understand the relation between accretion and the transportation of angular momentum and energy. We solve the radial momentum equation for solutions corresponding to an accretion flow that starts from a subsonic state at infinity, smoothly passes the fast critical point, then supersonically falls into the horizon of the black hole. The solutions always have the following features: 1) The specific energy of fluid particles remains constant but the specific angular momentum is effectively removed by the magnetic field. 2) At large radii, where the disk motion is dominantly rotational, the energy density of the magnetic field is equipartitioned with the rotational energy density of the disk. 3) Inside the fast critical point, where radial motion becomes important, the ratio of the electromagnetic energy density to the kinetic energy density drops quickly. The results indicate that: 1) Disk accretion does not necessarily imply energy dissipation since magnetic fields do not have to transport or dissipate a lot of energy as they effectively transport angular momentum. 2) When resistivity is small, the large-scale magnetic field is amplified by the shearing rotation of the disk until the magnetic energy density is equipartitioned with the rotational energy density, ending up with a geometrically thick disk. This is in contrast with the evolution of small-scale magnetic fields where if the resistivity is nonzero the magnetic energy density is likely to be equipartitioned with the kinetic energy density associated with local random motions (e.g., turbulence), making a thin Keplerian disk possible.
Cosmological variation of the MOND constant: secular effects on galactic systems
Mordehai Milgrom
2015-02-18
The proximity of the MOND acceleration constant with cosmological accelerations -- for example, a0 cH0/2pi -- points to its possibly decreasing with cosmic time. I begin to consider the secular changes induced in galactic systems by such presumed variations, assumed adiabatic. It is important to understand these effects, in isolation from other evolutionary influences, in order to identify or constrain a0 variations by detection of induced effects, or lack thereof. I find that as long as the system is fully in the deep-MOND regime -- as applies to many galactic systems -- the adiabatic response of the system obeys simple scaling laws. For example, in a system that would be stationary for fixed a0, the system expands homologously as a0^{-1/4}, while internal velocities decrease uniformly as a0^{1/4}. If a0 is proportional to cH at all relevant times, this change amounts to a factor of ~ 2.5 since redshift 10. For a system stationary in a rotating frame, the angular frequency decreases as a0^{1/2}. The accelerations increase relative to a0 as a0^{-1/4}, pushing the system towards the Newtonian regime. All this follows from the appearance of a0 in MOND and the scale invariance of the deep-MOND limit -- two basic tenets of MOND. More complicated evolution ensues when parts of the system become Newtonian, or are so from inception. For example, these parts may become unstable, not being protected by MOND's stabilizing effects. The existence of such regions also modifies the MONDian regime, since they affect the potential everywhere, and since constituents might migrate between the Newtonian and MONDian regimes. Studying these last effects would require detailed numerical calculations.
Type Ia Supernovae: Progenitors and Evolution with Redshift
Ken'ichi Nomoto; Hideyuki Umeda; Chiaki Kobayashi; Izumi Hachisu; Mariko Kato; Takuji Tsujimoto
2000-03-09
Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting WDs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction $X$(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependences of SNe Ia brightness on the galaxy types and the distance from the galactic center. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies.
Raskach, K. F., E-mail: raskachkf@mail.ru [Obninsk Institute for Physics and Power Engineering (Russian Federation)
2012-12-15
In multigroup calculations of reactivity and sensitivity coefficients, methodical errors can appear if the interdependence of multigroup constants is not taken into account. For this effect to be taken into account, so-called implicit components of the aforementioned values are introduced. A simple technique for computing these values is proposed. It is based on the use of subgroup parameters.
Swaminathan, Madhavan
transmission line, while the low state of the output data draws much less current. Thus, the DC dropMinimizing Simultaneous Switching Noise at Reduced Power with Constant-Voltage Power Transmission plane structure with a power transmission line (PTL). In this paper, a new power delivery scheme called
Andrei Vieru
2015-11-24
We believe that Euler constant is not just the "renormalized" value of the Riemann zeta function in 1. In a sense that we shall clarify it is in fact the normal and natural value of zeta of 1. In this paper we first propose a limit definition of a function whose values coincide everywhere with those of the Riemann zeta function, save in 1, where our limit definition yields the Euler constant. Since in the literature one can find more than one way to regularize the value of the zeta function at s=1, we give asymptotic expansions where, by dint of some extended analogies, Euler constant appears to be the true "renormalized" value. As a striking example of such analogies, we propose an expansion of the logarithm function based on Euler constant and on all values of the zeta function at odd positive integers, in which all these presumably irrational numbers are accompanied by Harmonic numbers of corresponding orders. The other aim of this paper is to show how sequences of rationals, often the same, arise in computations related to Dirichlet L-functions. Here, a connection with the Liouville lambda function appears to have been found. Thus we raise the question about the possible usefulness of an extension of the Liouville lambda function to rationals. .
V. M. Villalba; R. Pino
2001-01-23
We compute, via a variational mixed-base method, the energy spectrum of a two dimensional relativistic atom in the presence of a constant magnetic field of arbitrary strength. The results are compared to those obtained in the non-relativistic and spinless case. We find that the relativistic spectrum does not present $s$ states.
McCalley, James D.
of synchronous machines · Chapters 7-8: Excitation systems and Effect of excitation on stability · Chapter 9 performance of the generators. One advantage to using the constant Z-model is that it allows us to easily reduce the network to generator nodes as all loads are represented in the Y-bus. We obtain the impedance
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n 5
Anderson, Michael
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n that the recent work of Lee [24] implies existence of a large class of new singularity-free strictly static in all space-time dimensions greater than or equal to four, and leads both to strictly static solutions
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n 5
Delay, Erwann
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n [24] implies existence of a large class of new singularity-free strictly static Lorentzian vacuum-time dimensions greater than or equal to four, and leads both to strictly static solutions and to black hole
K. M. Pitman; A. M. Hofmeister; A. B. Corman; A. K. Speck
2008-03-10
Silicon Carbide (SiC) optical constants are fundamental inputs for radiative transfer models of astrophysical dust environments. However, previously published values contain errors and do not adequately represent the bulk physical properties of the cubic (beta) SiC polytype usually found around carbon stars. We provide new, uncompromised optical constants for beta- and alpha-SiC derived from single-crystal reflectance spectra and investigate quantitatively whether there is any difference between alpha- and beta-SiC that can be seen in infrared spectra and optical functions. Previous optical constants for SiC do not reflect the true bulk properties, and they are only valid for a narrow grain size range. The new optical constants presented here will allow narrow constraints to be placed on the grain size and shape distribution that dominate in astrophysical environments. In addition, our calculated absorption coefficients are much higher than laboratory measurements, which has an impact on the use of previous data to constrain abundances of these dust grains.
International Association for Cryptologic Research (IACR)
high expan- sion rate generators based on assumptions related to factoring [GR00,HSS93], we note). In return, we get a simpler generator where no hashing is necessary to extract the output (in contrastAn Efficient Pseudo-Random Generator with Applications to Public-Key Encryption and Constant
Zhao, Xiaopeng
the way the human brain operates [13]. ANNs are suited to problems of signal processing and reconstructionAbstract--Constant monitoring of a variety of physiological signals is vitally important in numerous clinical care settings. This signals are not perfect, however, and can be corrupted or lost
Paris-Sud XI, Université de
-wise linear costs Ay³e Akbal#25;k (1) and Christophe Rapine (2) (1) LTM #21; CNRS #21; UJF, 17, ave. des (CLSP). We consider a constant batch size production with a #28;xed cost associated to each batch, additionally to the production setup cost and a unit holding cost. The production cost can then be considered