Reactor control system upgrade for the McClellan Nuclear Radiation Center
Power, Michael A.
1999-01-01
a new reactor control system for the McClellan NuclearI REACTOR CONTROL SYSTEM UPGRADE FOR THE McCLELLAN NUCLEARReactor Control System Upgrade for the McClellan Nuclear
Vadose Zone Monitoring System Installation Report for McClellan AFB
Zawislanski, Peter
2010-01-01
neutron probe and relative lithologie log Vadose Zone Monitoring SystemMonitoring System Installation Report for McClellan AFB NeutronMonitoring System Installation Report for McClellan AFB 4.3 Neutron
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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4. Manufacturing Isovolumes Michael Bailey
Bailey, Mike
4. Manufacturing Isovolumes Michael Bailey 4.1 Introduction Displaying a single isosurface provides and then manufactures them, providing a non-volatile display of several isosurfaces. The inspiration for this idea, tetrahedralization produces more information than is necessary for prototype manufacturing. Prototype manufacturing
Field Mapping At Valles Caldera - Redondo Geothermal Area (Bailey...
based on surface mapping of the caldera. References Roy A. Bailey, Robert Leland Smith, Clarence Samuel Ross (1969) Stratigraphic Nomenclature of Volcanic Rocks in the Jemez...
Bailey County, Texas: Energy Resources | Open Energy Information
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Bailey's Crossroads, Virginia: Energy Resources | Open Energy Information
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Bailey County Elec Coop Assn | Open Energy Information
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Evaluating Homology Search Algorithms Timothy L. Bailey 1 Michael Gribskov 1
Bailey, Timothy L.
Evaluating Homology Search Algorithms Timothy L. Bailey 1 Michael Gribskov 1 tbailey, California 920930505 Keywords: accuracy comparison, homology algorithms, classification, pvalues 1 Introduction Both the users and developers of homology search algorithms have a natural interest in comparing
Using Layered Manufacturing for Scientific Visualization Mike Bailey, Oregon State University
Bailey, Mike
Manufacturing, on the other hand, is characterized by additive manufacturing processes. They start with nothing, but there are significant advantages to additive manufacturing for scientific visualization: · Extremely complex parts can1 Using Layered Manufacturing for Scientific Visualization Mike Bailey, Oregon State University
A Comparison of Methods for Sizing Energy Storage Devices in Renewable Energy Systems Thomas Bailey
Victoria, University of
A Comparison of Methods for Sizing Energy Storage Devices in Renewable Energy Systems by Thomas of Methods for Sizing Energy Storage Devices in Renewable Energy Systems by Thomas Bailey B.Eng, University, storage technologies are proposed as a means to increase the penetration of renewable energy, to minimize
B. Bruegmann
1993-12-02
The loop representation plays an important role in canonical quantum gravity because loop variables allow a natural treatment of the constraints. In these lectures we give an elementary introduction to (i) the relevant history of loops in knot theory and gauge theory, (ii) the loop representation of Maxwell theory, and (iii) the loop representation of canonical quantum gravity. (Based on lectures given at the 117. Heraeus Seminar, Bad Honnef, Sept. 1993)
COVERS FOR S-ACTS AND CONDITION (A) FOR A MONOID S ALEX BAILEY, VICTORIA GOULD, MIKLÂ´OS HARTMANNÂ´OS HARTMANN, JAMES RENSHAW, AND LUBNA SHAHEEN After some preliminaries, we give known equivalent
Atomic emission spectroscopy in high electric fields J. E. Bailey, A. B. Filuk, A. L. Carlson, D. J.76.50.6 On: Wed, 12 Mar 2014 07:27:49 #12;Atomic Emission Spectroscopyin HighElectricFields LE. Bailey, A, each driven with a high-power (~100 TW), ~30-nsec-duration pulse. Present experiments at the Particle
Baileys Hot Springs Pool & Spa Low Temperature Geothermal Facility | Open
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Gas Spring Losses in Linear Clearance Seal Compressors P.B. Bailey, M.W. Dadd, J.S. Reed*
1 Gas Spring Losses in Linear Clearance Seal Compressors P.B. Bailey, M.W. Dadd, J.S. Reed* , C, and the simplest demonstration of this can be observed in a gas spring. Our understanding of these gas spring with a clearance seal linear compressor attached to a plain gas spring volume. The static flow through
Environment Monitoring System (GEMS) of the United Nations Environment Programme, and the US Global Change173Bailey: Design ofEcologicalNetworksfor Monitoring Global Change Designof Ecological Networks for Monitoring Global Change World-wide monitoring of agricultural and other natural-resource ecosystems
Warne, Larry Kevin; Lucero, Larry Martin; Langston, William L.; Salazar, Robert Austin; Coleman, Phillip Dale; Basilio, Lorena I.; Bacon, Larry Donald
2012-05-01
This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.
Wright, Jonathan
2008-01-01
Gauvin Bailey?s account of how art was used and transformed by indigenous populations in Patagonian Chile, and Humberto Rodriguez-Camilloni?s chapter on the processions and festivals of coastal Peru. Perhaps most rewarding of all is Hiromitsu... of early Jesuit musical manuscripts by David Crook, a study of music in the Jesuits? German schools by Frank Korndle, insights into the Jesuit musical culture of colonial Chile by Victor Rondon, and detailed discussions by Bruna Filippi and Giovanna...
Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)
2002-09-10
A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.
Sparks, Donald L.
Relationship of Ammonium Nitrogen Distribution to Mineralogy in a Hapludalf Soil1 D. L. SPARKS, R. L. BLEVINS, H. H. BAILEY, AND R. I. BARNHISELZ ABSTRACT Distribution of fixed and exchangeable to the soil. Additional Index Words: silt mineralogy, clay mineralogy, exchangeable ammonium. Sparks, D. L., R
SPECIAL INITATIVE CONTACT: Stephanie McClellan
Firestone, Jeremy
@udel.edu Special Initiative on Offshore Wind (SIOW) at the University of Delaware The Atlantic coast offshore wind necessary to displace fossil fuels and address climate change. Atlantic offshore wind energy has several to large population centers that need the electricity. Additionally, unlike land-based wind, offshore wind
T. W. Brown
2008-05-07
We consider the one-loop two-point function for multi-trace operators in the U(2) sector of \\cN=4 supersymmetric Yang-Mills at finite N. We derive an expression for it in terms of U(N) and S_{n+1} group theory data, where n is the length of the operators. The Clebsch-Gordan operators constructed in 0711.0176, which are diagonal at tree level, only mix at one loop if you can reach the same (n+1)-box Young diagram by adding a single box to each of the n-box Young diagrams of their U(N) representations (which organise their multi-trace structure). Similar results are expected for higher loops and for other sectors of the global symmetry group.
NETL - Chemical Looping Reactor
2013-07-24
NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.
NETL - Chemical Looping Reactor
None
2014-06-26
NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.
Coupled dual loop absorption heat pump
Sarkisian, Paul H. (Watertown, MA); Reimann, Robert C. (Lafayette, NY); Biermann, Wendell J. (Fayetteville, NY)
1985-01-01
A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.
Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.; /Fermilab
2011-06-01
The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.
Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser
2010-04-12
We compute the three-loop corrections to the potential of two heavy quarks. In particular we consider in this Letter the purely gluonic contribution which provides in combination with the fermion corrections of Ref. \\cite{Smirnov:2008pn} the complete answer at three loops.
Shang, Jer-Yu (Fairfax, VA); Mei, Joseph S. (Morgantown, WV); Slagle, Frank D. (Kingwood, WV); Notestein, John E. (Morgantown, WV)
1984-01-01
The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.
Thermoelectric Power Generation System with Loop Thermosyphon...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Generation System with Loop Thermosyphon in Future High Efficiency Hybrid Vehicles Thermoelectric Power Generation System with Loop Thermosyphon in Future High Efficiency Hybrid...
Loop-deformed Poincaré algebra
Jakub Mielczarek
2013-04-08
In this essay we present evidence suggesting that loop quantum gravity leads to deformation of the local Poincar\\'e algebra within the limit of high energies. This deformation is a consequence of quantum modification of effective off-shell hypersurface deformation algebra. Surprisingly, the form of deformation suggests that the signature of space-time changes from Lorentzian to Euclidean at large curvatures. We construct particular realization of the loop-deformed Poincar\\'e algebra and find that it can be related to curved momentum space, which indicates the relationship with recently introduced notion of relative locality. The presented findings open a new way of testing loop quantum gravity effects.
Induction loop detector systems crosstalk
Bhagat, Victor
1994-01-01
traffic control systems are necessary to obtain maximum possible efficiency from our freeway systems. A major component of freeway management systems is the induction loop detector. This research effort evaluated the methods by which crosstalk could...
Measurability of Wilson loop operators
David Beckman; Daniel Gottesman; Alexei Kitaev; John Preskill
2001-10-22
We show that the nondemolition measurement of a spacelike Wilson loop operator W(C) is impossible in a relativistic non-Abelian gauge theory. In particular, if two spacelike-separated magnetic flux tubes both link with the loop C, then a nondemolition measurement of W(C) would cause electric charge to be transferred from one flux tube to the other, a violation of relativistic causality. A destructive measurement of W(C) is possible in a non-Abelian gauge theory with suitable matter content. In an Abelian gauge theory, many cooperating parties distributed along the loop C can perform a nondemolition measurement of the Wilson loop operator if they are equipped with a shared entangled ancilla that has been prepared in advance. We also note that Abelian electric charge (but not non-Abelian charge) can be transported superluminally, without any accompanying transmission of information.
Thermodynamics in Loop Quantum Cosmology
Li-Fang Li; Jian-Yang Zhu
2008-12-18
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but are actually also found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.
Chinese Magic in Loop Integrals
B. F. L. Ward
2011-06-02
We present an approach to higher point loop integrals using Chinese magic in the virtual loop integration variable. We show, using the five point function in the important e^+e^-\\to f\\bar{f}+\\gamma process for ISR as a pedagogical vehicle, that we get an expression for it directly reduced to one scalar 5-point function and 4-, 3-, and 2- point integrals, thereby avoiding the computation of the usual three tensor 5-pt Passarino-Veltman reduction. We argue that this offers potential for greater numerical stability.
Loop quantum gravity and observations
A. Barrau; J. Grain
2015-10-28
Quantum gravity has long been thought to be completely decoupled from experiments or observations. Although it is true that smoking guns are still missing, there are now serious hopes that quantum gravity phenomena might be tested. We review here some possible ways to observe loop quantum gravity effects either in the framework of cosmology or in astroparticle physics.
Detecting and escaping infinite loops using Bolt
Kling, Michael (Michael W.)
2012-01-01
In this thesis we present Bolt, a novel system for escaping infinite loops. If a user suspects that an executing program is stuck in an infinite loop, the user can use the Bolt user interface, which attaches to the running ...
ALTERNATIVE LOOP RINGS Kenneth Kunen \\Lambda
Kunen, Ken
ALTERNATIVE LOOP RINGS Kenneth Kunen \\Lambda University of Wisconsin, Madison, WI 53706, U.S.A. email: kunen@math.wisc.edu December 24, 1996 DRAFT Abstract The right alternative law implies the left alternative law in loop rings of characteristic other than 2. We also exhibit a loop which fails to be a right
McClellan, California: Energy Resources | Open Energy Information
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Calculating loops without loop calculations: NLO computation of pentaquark correlators
S. Groote; J. G. Körner; A. A. Pivovarov
2012-08-27
We compute next-to-leading order (NLO) perturbative QCD corrections to the correlators of interpolating pentaquark currents. We employ modular techniques in configuration space which saves us from the onus of having to do loop calculations. The modular technique is explained in some detail. We present explicit NLO results for several interpolating pentaquark currents that have been written down in the literature. Our modular approach is easily adapted to the case of NLO corrections to multiquark correlators with an arbitrary number of quarks/antiquarks.
Association schemes R. A. Bailey
Bailey, R. A.
top-secret message: SHOOT BORDS Should you SHOOT BORIS? SHOOT BIRDS? SHOOT LORDS? SHOOT BONDS? Coded
Bailey, R. A.
to display the proportions in the categories A and not-A was a pie-chart. 2/17 #12;Once upon a time in the categories A and not-A was a pie-chart. John disagreed rather strongly. 2/17 #12;From a conference poster
MARLON M. BAILEY Associate Professor
Indiana University
. GUTJAHR Professor Department of English The Book of Mormon: A Biography Princeton University, 2012 #12
Multiple randomizations R. A. Bailey
Bailey, R. A.
? For example, two-phase experiments, multistage reprocessing experiments, #12;Designing a simple experiment, multistage reprocessing experiments, superimposed experiments, #12;Designing a simple experiment: Fisher, multistage reprocessing experiments, superimposed experiments, ... #12;Plan of talk 1. Introduction #12;Plan
Marine Ecoregions Robert G. Bailey
influencing droughts, the interaction of marine-land systems in global climate change scenarios, and the Atlantic thermo-halide current and its potential role in starting and ending ice ages. [Note 6 Major ecosystems, or ecoregions · Result from predictable patterns of solar radiation and moisture
Chemical Looping | Open Energy Information
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Integration Rules for Loop Scattering Equations
Baadsgaard, Christian; Bourjaily, Jacob L; Damgaard, Poul H; Feng, Bo
2015-01-01
We formulate new integration rules for one-loop scattering equations analogous to those at tree-level, and test them in a number of non-trivial cases for amplitudes in scalar $\\phi^3$-theory. This formalism greatly facilitates the evaluation of amplitudes in the CHY representation at one-loop order, without the need to explicitly sum over the solutions to the loop-level scattering equations.
Polyakov loop renormalization with gradient flow
Peter Petreczky; Hans-Peter Schadler
2015-11-14
We propose to use the gradient flow for the renormalization of Polyakov loops in various representations. We study Polyakov loops in 2+1 flavor QCD using the HISQ action and lattices with temporal extents $N_\\tau$=6, 8, 10 and 12 in various representations, including fundamental, sextet, adjoint, decuplet, 15-plet and 27-plet. This alternative renormalization procedure allows for the renormalization over a large temperature range from $T$=100 MeV - 800 MeV, with small errors not only for the fundamental, but also for the higher representations of the Polyakov loop. We discuss the results of this procedure and Casimir scaling of the Polyakov loop.
Hard-thermal-loop QED thermodynamics
Nan Su; Jens O. Andersen; Michael Strickland
2009-11-24
The weak-coupling expansion for thermodynamic quantities in thermal field theories is poorly convergent unless the coupling constant is tiny. We discuss the calculation of the free energy for a hot gas of electrons and photons to three-loop order using hard-thermal-loop perturbation theory (HTLpt). We show that the hard-thermal-loop perturbation reorganization improves the convergence of the successive approximations to the QED free energy at large coupling, e ~ 2. The reorganization is gauge invariant by construction, and due to the cancellations among various contributions, we obtain a completely analytic result for the resummed thermodynamic potential at three loops.
Loop formation in polymers in crowded environment
K. Haydukivska; V. Blavatska
2015-11-12
We analyze the probability of a single loop formation in a long flexible polymer chain in disordered environment in $d$ dimensions. The structural defects are considered to be correlated on large distances $r$ according to a power law $\\sim r^{-a}$. Working within the frames of continuous chain model and applying the direct polymer renormalization scheme, we obtain the values of critical exponents governing the scaling of probabilities of loop formation with various positions along the chain as function of loops length. Our results quantitatively reveal that the presence of structural defects in environment decreases the probability of loop formation in polymer macromolecules.
UWB communication receiver feedback loop
Spiridon, Alex (Palo Alto, CA); Benzel, Dave (Livermore, CA); Dowla, Farid U. (Castro Valley, CA); Nekoogar, Faranak (San Ramon, CA); Rosenbury, Erwin T. (Castro Valley, CA)
2007-12-04
A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.
Closed loop steam cooled airfoil
Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.
2006-04-18
An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.
COCV'04 Preliminary Version Into the Loops
Goldberg, Benjamin
optimizations employed by Intel's ORC compiler. Tvoc, however, is somewhat limited when dealing with loop optimizations have been performed (in the case of the current ORC, this instrumentation is fortunately part transformations performed by the Intel ORC compiler. Key words: Translation validation, formal methods, loop
Ground Loops for Heat Pumps and Refrigeration
Braud, H. J.
1986-01-01
Ground loops are used for water source heat pumps. Refrigeration can be put on a ground loop. Water-cooled condensing units are more efficient than air-cooled, and they can be put indoors. Indoor location makes piping for desuperheater hot water...
Damped transverse oscillations of interacting coronal loops
Soler, Roberto
2015-01-01
Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations compared to those of an isolated loop. Here we theoretically investigate resonantly damped transverse oscillations of interacting non-uniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. ...
Detecting Neutrino Magnetic Moments with Conducting Loops
Apyan, Aram; Schmitt, Michael
2007-01-01
It is well established that neutrinos have mass, yet it is very difficult to measure those masses directly. Within the standard model of particle physics, neutrinos will have an intrinsic magnetic moment proportional to their mass. We examine the possibility of detecting the magnetic moment using a conducting loop. According to Faraday's Law of Induction, a magnetic dipole passing through a conducting loop induces an electromotive force, or EMF, in the loop. We compute this EMF for neutrinos in several cases, based on a fully covariant formulation of the problem. We discuss prospects for a real experiment, as well as the possibility to test the relativistic formulation of intrinsic magnetic moments.
Detecting Neutrino Magnetic Moments with Conducting Loops
Aram Apyan; Armen Apyan; Michael Schmitt
2007-09-23
It is well established that neutrinos have mass, yet it is very difficult to measure those masses directly. Within the standard model of particle physics, neutrinos will have an intrinsic magnetic moment proportional to their mass. We examine the possibility of detecting the magnetic moment using a conducting loop. According to Faraday's Law of Induction, a magnetic dipole passing through a conducting loop induces an electromotive force, or EMF, in the loop. We compute this EMF for neutrinos in several cases, based on a fully covariant formulation of the problem. We discuss prospects for a real experiment, as well as the possibility to test the relativistic formulation of intrinsic magnetic moments.
Quantum Loops in Non-Local Gravity
Talaganis, Spyridon
2015-01-01
In this proceedings, I will consider quantum aspects of a non-local, infinite-derivative scalar field theory - a ${\\it toy \\, model}$ depiction of a covariant infinite-derivative, non-local extension of Einstein's general relativity which has previously been shown to be free from ghosts around the Minkowski background. The graviton propagator in this theory gets an exponential suppression making it ${\\it asymptotically \\, free}$, thus providing strong prospects of resolving various classical and quantum divergences. In particular, I will find that at $1$-loop, the $2$-point function is still divergent, but once this amplitude is renormalized by adding appropriate counter terms, the ultraviolet (UV) behavior of all other $1$-loop diagrams as well as the $2$-loop, $2$-point function remains well under control. I will go on to discuss how one may be able to generalize our computations and arguments to arbitrary loops.
Loop spaces in motivic homotopy theory
Decker, Marvin Glen
2009-06-02
In topology loop spaces can be understood combinatorially using algebraic theories. This approach can be extended to work for certain model structures on categories of presheaves over a site with functorial unit interval objects, such as topological...
Energy release in driven twisted coronal loops
Bareford, M R; Browning, P K; Hood, A W
2015-01-01
In the present study we investigate magnetic reconnection in twisted magnetic fluxtubes with different initial configurations. In all considered cases, energy release is triggered by the ideal kink instability, which is itself the result of applying footpoint rotation to an initially potential field. The main goal of this work is to establish the influence of the field topology and various thermodynamic effects on the energy release process. Specifically, we investigate convergence of the magnetic field at the loop footpoints, atmospheric stratification, as well as thermal conduction. In all cases, the application of vortical driving at the footpoints of an initally potential field leads to an internal kink instability. With the exception of the curved loop with high footpoint convergence, the global geometry of the loop change little during the simulation. Footpoint convergence, curvature and atmospheric structure clearly influences the rapidity with which a loop achieves instability as well as the size of t...
Siphon flow in a cool magnetic loop
Bethge, C; Peter, H; Lagg, A
2011-01-01
We investigate the properties of a structure in the solar chromosphere in an active region to find out whether the feature is consistent with a siphon flow in a magnetic loop filled with chromospheric material.
The Three-Loop Lattice Free Energy
B. Alles; M. Campostrini; A. Feo; H. Panagopoulos
2005-08-15
We calculate the free energy of SU(N) gauge theories on the lattice, to three loops. Our result, combined with Monte Carlo data for the average plaquette, gives a more precise estimate of the gluonic condensate.
The Art of Computing Loop Integrals
Stefan Weinzierl
2006-04-07
A perturbative approach to quantum field theory involves the computation of loop integrals, as soon as one goes beyond the leading term in the perturbative expansion. First I review standard techniques for the computation of loop integrals. In a second part I discuss more advanced algorithms. For these algorithms algebraic methods play an important role. A special section is devoted to multiple polylogarithms. I tried to make these notes self-contained and accessible both to physicists and mathematicians.
Effective potential for SU(2) Polyakov loops and Wilson loop eigenvalues
Dominik Smith; Adrian Dumitru; Robert Pisarski; Lorenz von Smekal
2013-07-24
We simulate SU(2) gauge theory at temperatures ranging from slightly below $T_c$ to roughly $2T_c$ for two different values of the gauge coupling. Using a histogram method, we extract the effective potential for the Polyakov loop and for the phases of the eigenvalues of the thermal Wilson loop, in both the fundamental and adjoint representations. We show that the classical potential of the fundamental loop can be parametrized within a simple model which includes a Vandermonde potential and terms linear and quadratic in the Polyakov loop. We discuss how parametrizations for the other cases can be obtained from this model.
Hybrid Combustion-Gasification Chemical Looping
Herbert Andrus; Gregory Burns; John Chiu; Gregory Lijedahl; Peter Stromberg; Paul Thibeault
2009-01-07
For the past several years Alstom Power Inc. (Alstom), a leading world-wide power system manufacturer and supplier, has been in the initial stages of developing an entirely new, ultra-clean, low cost, high efficiency power plant for the global power market. This new power plant concept is based on a hybrid combustion-gasification process utilizing high temperature chemical and thermal looping technology The process consists of the oxidation, reduction, carbonation, and calcination of calcium-based compounds, which chemically react with coal, biomass, or opportunity fuels in two chemical loops and one thermal loop. The chemical and thermal looping technology can be alternatively configured as (i) a combustion-based steam power plant with CO{sub 2} capture, (ii) a hybrid combustion-gasification process producing a syngas for gas turbines or fuel cells, or (iii) an integrated hybrid combustion-gasification process producing hydrogen for gas turbines, fuel cells or other hydrogen based applications while also producing a separate stream of CO{sub 2} for use or sequestration. In its most advanced configuration, this new concept offers the promise to become the technology link from today's Rankine cycle steam power plants to tomorrow's advanced energy plants. The objective of this work is to develop and verify the high temperature chemical and thermal looping process concept at a small-scale pilot facility in order to enable AL to design, construct and demonstrate a pre-commercial, prototype version of this advanced system. In support of this objective, Alstom and DOE started a multi-year program, under this contract. Before the contract started, in a preliminary phase (Phase 0) Alstom funded and built the required small-scale pilot facility (Process Development Unit, PDU) at its Power Plant Laboratories in Windsor, Connecticut. Construction was completed in calendar year 2003. The objective for Phase I was to develop the indirect combustion loop with CO{sub 2} separation, and also syngas production from coal with the calcium sulfide (CaS)/calcium sulfate (CaSO{sub 4}) loop utilizing the PDU facility. The results of Phase I were reported in Reference 1, 'Hybrid Combustion-Gasification Chemical Looping Coal Power Development Technology Development Phase I Report' The objective for Phase II was to develop the carbonate loop--lime (CaO)/calcium carbonate (CaCO{sub 3}) loop, integrate it with the gasification loop from Phase I, and ultimately demonstrate the feasibility of hydrogen production from the combined loops. The results of this program were reported in Reference 3, 'Hybrid Combustion-Gasification Chemical Looping Coal Power Development Technology Development Phase II Report'. The objective of Phase III is to operate the pilot plant to obtain enough engineering information to design a prototype of the commercial Chemical Looping concept. The activities include modifications to the Phase II Chemical Looping PDU, solids transportation studies, control and instrumentation studies and additional cold flow modeling. The deliverable is a report making recommendations for preliminary design guidelines for the prototype plant, results from the pilot plant testing and an update of the commercial plant economic estimates.
Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated Wood
Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated Wood estimated that about 5 million tons of spent preservative treated wood istons of spent preservative treated wood is disposed of annually into landfills in thedisposed of annually into landfills in the United
Johansson, Karl Henrik
Wireless Networks: Fundamentals and Applications Karl H. Johansson Electrical Engineering, Royal Institute4/9/2008 1 Closing the Loop over Wireless Networks:Closing the Loop over Wireless Networks: Fundamentals and Applications Karl H. Johansson Electrical Engineering, Royal Institute of Technology Stockholm
Bootstrapping the Three-Loop Hexagon
Dixon, Lance J.; Drummond, James M.; Henn, Johannes M.; /Humboldt U., Berlin /Santa Barbara, KITP
2011-11-08
We consider the hexagonal Wilson loop dual to the six-point MHV amplitude in planar N = 4 super Yang-Mills theory. We apply constraints from the operator product expansion in the near-collinear limit to the symbol of the remainder function at three loops. Using these constraints, and assuming a natural ansatz for the symbol's entries, we determine the symbol up to just two undetermined constants. In the multi-Regge limit, both constants drop out from the symbol, enabling us to make a non-trivial confirmation of the BFKL prediction for the leading-log approximation. This result provides a strong consistency check of both our ansatz for the symbol and the duality between Wilson loops and MHV amplitudes. Furthermore, we predict the form of the full three-loop remainder function in the multi-Regge limit, beyond the leading-log approximation, up to a few constants representing terms not detected by the symbol. Our results confirm an all-loop prediction for the real part of the remainder function in multi-Regge 3 {yields} 3 scattering. In the multi-Regge limit, our result for the remainder function can be expressed entirely in terms of classical polylogarithms. For generic six-point kinematics other functions are required.
Entropic Motion in Loop Quantum Gravity
J. Manuel Garcia-Islas
2015-02-19
Entropic forces result from an increase of the entropy of a thermodynamical physical system. It has been proposed that gravity is such a phenomenon and many articles have appeared on the literature concerning this problem. Loop quantum gravity has also considered such possibility. We propose a new method in loop quantum gravity which reproduces an entropic force. By considering the interaction between a fixed gravity state space and a particle state in loop quantum gravity, we show that it leads to a mathematical description of a random walk of such particle. The random walk in special situations, can be seen as an entropic motion in such a way that the particle will move towards a location where entropy increases. This may prove that such theory can reproduce gravity as it is expected.
Automation of one-loop QCD corrections
Valentin Hirschi; Rikkert Frederix; Stefano Frixione; Maria Vittoria Garzelli; Fabio Maltoni; Roberto Pittau
2013-05-14
We present the complete automation of the computation of one-loop QCD corrections, including UV renormalization, to an arbitrary scattering process in the Standard Model. This is achieved by embedding the OPP integrand reduction technique, as implemented in CutTools, into the MadGraph framework. By interfacing the tool so constructed, which we dub MadLoop, with MadFKS, the fully automatic computation of any infrared-safe observable at the next-to-leading order in QCD is attained. We demonstrate the flexibility and the reach of our method by calculating the production rates for a variety of processes at the 7 TeV LHC.
Selective purge for hydrogenation reactor recycle loop
Baker, Richard W.; Lokhandwala, Kaaeid A.
2001-01-01
Processes and apparatus for providing improved contaminant removal and hydrogen recovery in hydrogenation reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the hydrogenation reactor recycle loop or purge stream across membranes selective in favor of the contaminant over hydrogen.
Loop expansion in Yang-Mills thermodynamics
Ralf Hofmann
2009-11-05
We argue that a selfconsistent spatial coarse-graining, which involves interacting (anti)calorons of unit topological charge modulus, implies that real-time loop expansions of thermodynamical quantities in the deconfining phase of SU(2) and SU(3) Yang-Mills thermodynamics are, modulo 1PI resummations, determined by a finite number of connected bubble diagrams.
Battery Hardware in the Loop | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Hardware in the Loop Battery Hardware in the Loop Presentation from the U.S. DOE Office of Vehicle Technologies "Mega" Merit Review 2008 on February 25, 2008 in Bethesda, Maryland....
Parametric Multi-Level Tiling of Imperfectly Nested Loops
Hartono, Albert; Baskaran, Muthu M.; Bastoul, Cedric; Cohen, Albert; Krishnamoorthy, Sriram; Norris, Boyana; Ramanujam, J.; Sadayappan, Ponnuswamy
2009-05-18
Tiling is a critical loop transformation for generating high-performance code on modern architectures. Efficient generation of multilevel tiled code is essential to exploit several levels of parallelism and/or to maximize data reuse in deep memory hierarchies. Tiled loops with parameterized tile sizes (not compile time constants) facilitate runtime feedback and dynamic optimizations used in iterative compilation and automatic tuning. The existing parametric multilevel tiling approach has focused on transformation for perfectly nested loops, where all assignment statements are contained inside the innermost loop of a loop nest. Previous solutions to tiling for imperfect loop nests are limited to the case where tile sizes are fixed. In this paper, we present an approach to parameterized multilevel tiling for imperfectly nested loops. Our tiling algorithm generates loops that iterate over full rectangular tiles that are amenable for potential compiler optimizations such as register tiling. Experimental results using a number of computational benchmarks demonstrate the effectiveness of our tiling approach.
Loop simulation capability for sodium-cooled systems
Adekugbe, Oluwole A.
1984-01-01
A one-dimensional loop simulation capability has been implemented in the thermal-hydraulic analysis code, THERMIT-4E. This code had been used to simulate and investigate flow in test sections of experimental sodium loops ...
Closed loop pulsating heat pipes Part A: parametric experimental investigations
Khandekar, Sameer
Closed loop pulsating heat pipes Part A: parametric experimental investigations Piyanun; accepted 1 May 2003 Abstract Closed loop pulsating heat pipes (CLPHPs) are complex heat transfer devices range of pulsating heat pipes is experimentally studied thereby providing vital information
ORC Closed Loop Control Systems for Transient and Steady State...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
ORC Closed Loop Control Systems for Transient and Steady State Duty Cycles ORC Closed Loop Control Systems for Transient and Steady State Duty Cycles System-level models using...
Violation of the Holographic Principle in the Loop Quantum Gravity
Ozan Sarg?n; Mir Faizal
2015-09-01
In this paper, we analyze the holographic principle using loop quantum gravity (LQG). This will be done by analysing a simple quantum mechanical system using polymeric quantization. As the polymeric quantization is the characteristic feature of loop quantum gravity, we will argue that this calculation will indicate the effect on the holographic principle from the loop quantum gravity. Thus, we will be able to explicitly demonstrate the violation of the holographic principle in the loop quantum gravity.
Six-loop divergences in the supersymmetric Kahler sigma model
I. Jack; D. R. T. Jones; J. Panvel
1993-11-19
The two-dimensional supersymmetric $\\s$-model on a K\\"ahler manifold has a non-vanishing $\\b$-function at four loops, but the $\\b$-function at five loops can be made to vanish by a specific choice of renormalisation scheme. We investigate whether this phenomenon persists at six loops, and conclude that it does not; there is a non-vanishing six-loop $\\b$-function irrespective of renormalisation scheme ambiguities.
On Termination of Integer Linear Loops Joel Ouaknine
Oxford, University of
On Termination of Integer Linear Loops JoÂ¨el Ouaknine Department of Computer Science Oxford con- cerns the termination of simple linear loops of the form: x u ; while Bx c do x Ax + a , where initial integer vectors u, such a loop terminates. The correctness of our algorithm relies
Managing Performance vs. Accuracy Trade-offs With Loop Perforation
Polz, Martin
Managing Performance vs. Accuracy Trade-offs With Loop Perforation Stelios Sidiroglou Sasa-hoc, domain-specific techniques developed specifically for the computation at hand. Loop perforation provides of their iterations. A criticality testing phase filters out critical loops (whose perforation produces unacceptable
A speech locked loop for cochlear implants and speech prostheses
Wee, Keng Hoong
We have previously described a feedback loop that combines an auditory processor with a low-power analog integrated-circuit vocal tract to create a speech-locked-loop. Here, we describe how the speech-locked loop can help ...
Fermion Doubling in Loop Quantum Gravity
Jacob Barnett; Lee Smolin
2015-07-05
In this paper, we show that the Hamiltonian approach to loop quantum gravity has a fermion doubling problem. To obtain this result, we couple loop quantum gravity to a free massless scalar and a chiral fermion field, gauge fixing the many fingered time gauge invariance by interpreting the scalar field as a physical clock. We expand around a quantum gravity state based on a regular lattice and consider the limit where the bare cosmological constant is large but the fermonic excitations have energies low in Planck units. We then make the case for identifying the energy spectrum in this approximation with that of a model of lattice fermion theory which is known to double.
A new vacuum for Loop Quantum Gravity
Bianca Dittrich; Marc Geiller
2015-05-05
We construct a new vacuum for loop quantum gravity, which is dual to the Ashtekar-Lewandowski vacuum. Because it is based on BF theory, this new vacuum is physical for $(2+1)$-dimensional gravity, and much closer to the spirit of spin foam quantization in general. To construct this new vacuum and the associated representation of quantum observables, we introduce a modified holonomy-flux algebra which is cylindrically consistent with respect to the notion of refinement by time evolution suggested in [1]. This supports the proposal for a construction of a physical vacuum made in [1,2], also for $(3+1)$-dimensional gravity. We expect that the vacuum introduced here will facilitate the extraction of large scale physics and cosmological predictions from loop quantum gravity.
Loop Gas Model for Open Strings
V. Kazakov; I. Kostov
1992-05-18
The open string with one-dimensional target space is formulated in terms of an SOS, or loop gas, model on a random surface. We solve an integral equation for the loop amplitude with Dirichlet and Neumann boundary conditions imposed on different pieces of its boundary. The result is used to calculate the mean values of order and disorder operators, to construct the string propagator and find its spectrum of excitations. The latter is not sensible neither to the string tension $\\L$ nor to the mass $\\mu$ of the ``quarks'' at the ends of the string. As in the case of closed strings, the SOS formulation allows to construct a Feynman diagram technique for the string interaction amplitudes.
Closed-loop pulsed helium ionization detector
Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)
1987-01-01
A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.
FLOWS OF MASS, MOMENTUM AND ENERGY IN THE SOLAR ATMOSPHERE A SOHOORIENTED VIEW OF COLD LOOPS
siphon flow loop models leads to the conclusion that such loop cannot be in steady state; in particular
MAGNETIC LOOPS IN THE QUIET SUN
Wiegelmann, T.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Borrero, J. M.; Schmidt, W.; Pillet, V. MartInez; Bonet, J. A.; Domingo, V.; Knoelker, M.; Title, A. M.
2010-11-10
We investigate the fine structure of magnetic fields in the atmosphere of the quiet Sun. We use photospheric magnetic field measurements from SUNRISE/IMaX with unprecedented spatial resolution to extrapolate the photospheric magnetic field into higher layers of the solar atmosphere with the help of potential and force-free extrapolation techniques. We find that most magnetic loops that reach into the chromosphere or higher have one footpoint in relatively strong magnetic field regions in the photosphere. Ninety-one percent of the magnetic energy in the mid-chromosphere (at a height of 1 Mm) is in field lines, whose stronger footpoint has a strength of more than 300 G, i.e., above the equipartition field strength with convection. The loops reaching into the chromosphere and corona are also found to be asymmetric in the sense that the weaker footpoint has a strength B < 300 G and is located in the internetwork (IN). Such loops are expected to be strongly dynamic and have short lifetimes, as dictated by the properties of the IN fields.
Gas Test Loop Booster Fuel Hydraulic Testing
Gas Test Loop Hydraulic Testing Staff
2006-09-01
The Gas Test Loop (GTL) project is for the design of an adaptation to the Advanced Test Reactor (ATR) to create a fast-flux test space where fuels and materials for advanced reactor concepts can undergo irradiation testing. Incident to that design, it was found necessary to make use of special booster fuel to enhance the neutron flux in the reactor lobe in which the Gas Test Loop will be installed. Because the booster fuel is of a different composition and configuration from standard ATR fuel, it is necessary to qualify the booster fuel for use in the ATR. Part of that qualification is the determination that required thermal hydraulic criteria will be met under routine operation and under selected accident scenarios. The Hydraulic Testing task in the GTL project facilitates that determination by measuring flow coefficients (pressure drops) over various regions of the booster fuel over a range of primary coolant flow rates. A high-fidelity model of the NW lobe of the ATR with associated flow baffle, in-pile-tube, and below-core flow channels was designed, constructed and located in the Idaho State University Thermal Fluids Laboratory. A circulation loop was designed and constructed by the university to provide reactor-relevant water flow rates to the test system. Models of the four booster fuel elements required for GTL operation were fabricated from aluminum (no uranium or means of heating) and placed in the flow channel. One of these was instrumented with Pitot tubes to measure flow velocities in the channels between the three booster fuel plates and between the innermost and outermost plates and the side walls of the flow annulus. Flow coefficients in the range of 4 to 6.5 were determined from the measurements made for the upper and middle parts of the booster fuel elements. The flow coefficient for the lower end of the booster fuel and the sub-core flow channel was lower at 2.3.
Exact scheme independence at one loop
Stefano Arnone; Antonio Gatti; Tim R. Morris
2002-06-10
The requirement that the quantum partition function be invariant under a renormalization group transformation results in a wide class of exact renormalization group equations, differing in the form of the kernel. Physical quantities should not be sensitive to the particular choice of the kernel. We demonstrate this scheme independence in four dimensional scalar field theory by showing that, even with a general kernel, the one-loop beta function may be expressed only in terms of the effective action vertices, and thus, under very general conditions, the universal result is recovered.
Exact scheme independence at one loop
Arnone, S; Morris, T R; Arnone, Stefano; Gatti, Antonio; Morris, Tim R.
2002-01-01
The requirement that the quantum partition function be invariant under a renormalization group transformation results in a wide class of exact renormalization group equations, differing in the form of the kernel. Physical quantities should not be sensitive to the particular choice of the kernel. We demonstrate this scheme independence in four dimensional scalar field theory by showing that, even with a general kernel, the one-loop beta function may be expressed only in terms of the effective action vertices, and thus, under very general conditions, the universal result is recovered.
Loop Quantum Gravity: An Inside View
Thomas Thiemann
2006-08-29
This is a (relatively) non -- technical summary of the status of the quantum dynamics in Loop Quantum Gravity (LQG). We explain in detail the historical evolution of the subject and why the results obtained so far are non -- trivial. The present text can be viewed in part as a response to an article by Nicolai, Peeters and Zamaklar [hep-th/0501114]. We also explain why certain no go conclusions drawn from a mathematically correct calculation in a recent paper by Helling et al [hep-th/0409182] are physically incorrect.
Thermoelectric power generator with intermediate loop
Bell, Lon E; Crane, Douglas Todd
2013-05-21
A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.
Thermoelectric power generator with intermediate loop
Bel,; Lon E. (Altadena, CA); Crane, Douglas Todd (Pasadena, CA)
2009-10-27
A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.
Chemical Looping Combustion | netl.doe.gov
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 OutreachProductswsicloudwsiclouddenDVA N C E D BGene NetworkNuclear SecurityChattan ooga Eag leChemical Looping
Renormalization of the Polyakov loop with gradient flow
P. Petreczky; H. -P. Schadler
2015-11-24
We use the gradient flow for the renormalization of the Polyakov loop in various representations. Using 2+1 flavor QCD with highly improved staggered quarks and lattices with temporal extents of $N_\\tau=6$, $8$, $10$ and $12$ we calculate the renormalized Polyakov loop in many representations including fundamental, sextet, adjoint, decuplet, 15-plet, 24-plet and 27-plet. This approach allows for the calculations of the renormalized Polyakov loops over a large temperature range from $T=116$ MeV up to $T=815$ MeV, with small errors not only for the Polyakov loop in fundamental representation, but also for the Polyakov loops in higher representations. We compare our results with standard renormalization schemes and discuss the Casimir scaling of the Polyakov loops.
Quantum Corrections in Galileons from Matter Loops
Lavinia Heisenberg
2014-10-09
Galileon interactions represent a class of effective field theories that have received much attention since their inception. They can be treated in their own right as scalar field theories with a specific global shift and Galilean symmetry or as a descendant of a more fundamental theory like massive gravity. It is well known that the Galileon theories are stable under quantum corrections thanks to the non-renormalization theorem which is not due to the symmetry. We consider different covariant couplings of this Galileon scalar field with the matter field: the conformal coupling, the disformal coupling and the longitudinal coupling. We compute the one-loop quantum corrections to the Galileon interactions from the coupling to the external matter fields. In all the considered cases of covariant couplings we show that the terms generated by one-loop matter corrections not only renormalize the Galileon interactions but also give rise to higher order derivative ghost interactions. However, the renormalized version of the Galileon interactions as well as the new interactions come at a scale suppressed by the original classical coupling scale and hence are harmless within the regime of validity of the effective field theory.
Entropy mode loops and cosmological correlations during perturbative reheating
Kaya, Ali; Kutluk, Emine Seyma E-mail: seymakutluk@gmail.com
2015-01-01
Recently, it has been shown that during preheating the entropy modes circulating in the loops, which correspond to the inflaton decay products, meaningfully modify the cosmological correlation functions at superhorizon scales. In this paper, we determine the significance of the same effect when reheating occurs in the perturbative regime. In a typical two scalar field model, the magnitude of the loop corrections are shown to depend on several parameters like the background inflaton amplitude in the beginning of reheating, the inflaton decay rate and the inflaton mass. Although the loop contributions turn out to be small as compared to the preheating case, they still come out larger than the loop effects during inflation.
Evolution equation for 3-quark Wilson loop operator
R. E. Gerasimov; A. V. Grabovsky
2012-12-07
The evolution equation for the 3 quark Wilson loop operator has been derived in the leading logarithm approximation within Balitsky high energy operator expansion.
Finite-dimensional representations of twisted hyper loop algebras
Bianchi, Angelo
2012-01-01
We investigate the category of finite-dimensional representations of twisted hyper loop algebras, i.e., the hyperalgebras associated to twisted loop algebras over finite-dimensional simple Lie algebras. The main results are the classification of the irreducible modules, the definition of the universal highest-weight modules, called the Weyl modules, and, under a certain mild restriction on the characteristic of the ground field, a proof that the simple modules and the Weyl modules for the twisted hyper loop algebras are isomorphic to appropriate simple and Weyl modules for the non-twisted hyper loop algebras, respectively, via restriction of the action.
Static properties of nuclear matter within the Boson Loop Expansion
W. M. Alberico; R. Cenni; G. Garbarino; M. R. Quaglia
2007-10-24
The use of the Boson Loop Expansion is proposed for investigating the static properties of nuclear matter. We explicitly consider a schematic dynamical model in which nucleons interact with the scalar-isoscalar sigma meson. The suggested approximation scheme is examined in detail at the mean field level and at the one- and two-loop orders. The relevant formulas are provided to derive the binding energy per nucleon, the pressure and the compressibility of nuclear matter. Numerical results of the binding energy at the one-loop order are presented for Walecka's sigma-omega model in order to discuss the degree of convergence of the Boson Loop Expansion.
Desert dust suppressing precipitation: A possible desertification feedback loop
Daniel, Rosenfeld
Desert dust suppressing precipitation: A possible desertification feedback loop Daniel Rosenfeld of land use exposing the topsoil can initiate such a desertification feedback process. Satellite
DATE: December 9, 2011 TO: Bailey Residents
Janssen, Michel
floor or in the lobby. No questions asked! Turn off all lights. Lock your door and take your keys and disciplinary action may be taken. North Wing residents: Leave your heating unit fan on "low" and the temperature setting on "warm". Please remove all items from the top and front of the heating unit. INFORMATION
Jim Bailey | Y-12 National Security Complex
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Kay Bailey | Y-12 National Security Complex
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Ed Bailey | Y-12 National Security Complex
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Exact scheme independence at two loops
Stefano Arnone; Antonio Gatti; Tim R. Morris; Oliver J. Rosten
2003-11-11
We further develop an algorithmic and diagrammatic computational framework for very general exact renormalization groups, where the embedded regularisation scheme, parametrised by a general cutoff function and infinitely many higher point vertices, is left unspecified. Calculations proceed iteratively,by integrating by parts with respect to the effective cutoff, thus introducing effective propagators, and differentials of vertices that can be expanded using the flow equations; many cancellations occur on using the fact that the effective propagator is the inverse of the classical Wilsonian two-point vertex. We demonstrate the power of these methods by computing the beta function up to two loops in massless four dimensional scalar field theory, obtaining the expected universal coefficients, independent of the details of the regularisation scheme.
TeGrotenhuis, Ward Evan
2013-11-05
A drying apparatus is disclosed that includes a drum and an open-loop airflow pathway originating at an ambient air inlet, passing through the drum, and terminating at an exhaust outlet. A passive heat exchanger is included for passively transferring heat from air flowing from the drum toward the exhaust outlet to air flowing from the ambient air inlet toward the drum. A heat pump is also included for actively transferring heat from air flowing from the passive heat exchanger toward the exhaust outlet to air flowing from the passive heat exchanger toward the drum. A heating element is also included for further heating air flowing from the heat pump toward the drum.
Gas Test Loop Functional and Technical Requirements
Glen R. Longhurst; Soli T. Khericha; James L. Jones
2004-09-01
This document defines the technical and functional requirements for a gas test loop (GTL) to be constructed for the purpose of providing a high intensity fast-flux irradiation environment for developers of advanced concept nuclear reactors. This capability is needed to meet fuels and materials testing requirements of the designers of Generation IV (GEN IV) reactors and other programs within the purview of the Advanced Fuel Cycle Initiative (AFCI). Space nuclear power development programs may also benefit by the services the GTL will offer. The overall GTL technical objective is to provide developers with the means for investigating and qualifying fuels and materials needed for advanced reactor concepts. The testing environment includes a fast-flux neutron spectrum of sufficient intensity to perform accelerated irradiation testing. Appropriate irradiation temperature, gaseous environment, test volume, diagnostics, and access and handling features are also needed. This document serves to identify those requirements as well as generic requirements applicable to any system of this kind.
Electricity generation with looped transmission networks: Bidding to an ISO
Ferris, Michael C.
Electricity generation with looped transmission networks: Bidding to an ISO Xinmin Hu Daniel Ralph to model markets for delivery of electrical power on looped transmission networks. It analyzes, 2323 Audubon St, New Orleans, LA 70125-4117, USA; www.EKonomicsLLC.com ¶ Department of Economics
Analysis of heat transfer in unlooped and looped pulsating
Zhang, Yuwen
to the exchange of sensible heat. Higher surface tension results in a slight increase in the total heat transfer into turns. There are two types of PHPs: the looped pulsating heat pipe and the unlooped pulsating heat pipeAnalysis of heat transfer in unlooped and looped pulsating heat pipes M.B. Sha®i and A. Faghri
Supply Regulation Techniques for Phase-Locked Loops
Palermo, Sam
Supply Regulation Techniques for Phase-Locked Loops Vivekananth Gurumoorthy and Samuel Palermo-- Phase-locked loops (PLLs) which employ voltage regulators for low supply-noise sensitivity often rely. This paper compares various supply regulation techniques on the basis of their ability to reject noise from
The static quark potential to three loops in perturbation theory
Alexander V. Smirnov; Vladimir A. Smirnov; Matthias Steinhauser
2010-06-29
The static potential constitutes a fundamental quantity of Quantum Chromodynamics. It has recently been evaluated to three-loop accuracy. In this contribution we provide details on the calculation and present results for the 14 master integrals which contain a massless one-loop insertion.
Singlet Free Energies and Renormalized Polyakov Loop in full QCD
K. Petrov
2006-10-05
We calculate the free energy of a static quark anti-quark pair and the renormalized Polyakov loop in 2+1- and 3- flavor QCD using $16^3 \\times 4$ and $16^3 \\times 6$ lattices and improved staggered p4 action. We also compare the renormalized Polyakov loop with the results of our earlier studies.
Loop summarization and termination analysis Aliaksei Tsitovich1
KrÃ¶ning, Daniel
Loop summarization and termination analysis Aliaksei Tsitovich1 , Natasha Sharygina1 , Christoph M termination analysis based on loop summarization. The algorithm relies on a library of ab- stract domains Introduction The program termination problem has received increased interest in the recent past. In practice
Efficiently finding optimal winding-constrained loops in the plane
Vernaza, Paul
Efficiently finding optimal winding- constrained loops in the plane Paul Vernaza, Venkatraman winding- constrained loops in the plane that are optimal with respect to a minimum-cost objective times it winds around each obstacle, enabling us to reduce the problem of finding paths satisfying
Bolt: On-Demand Infinite Loop Escape in Unmodified Binaries
Rinard, Martin
. Bolt supports an on- demand usage model--a user can attach Bolt to a running application at any point the application has successfully escaped from the loop, Bolt detaches from the application. To support the onBolt: On-Demand Infinite Loop Escape in Unmodified Binaries Michael Kling Sasa Misailovic Michael
Control and optimization system and method for chemical looping processes
Lou, Xinsheng; Joshi, Abhinaya; Lei, Hao
2014-06-24
A control system for optimizing a chemical loop system includes one or more sensors for measuring one or more parameters in a chemical loop. The sensors are disposed on or in a conduit positioned in the chemical loop. The sensors generate one or more data signals representative of an amount of solids in the conduit. The control system includes a data acquisition system in communication with the sensors and a controller in communication with the data acquisition system. The data acquisition system receives the data signals and the controller generates the control signals. The controller is in communication with one or more valves positioned in the chemical loop. The valves are configured to regulate a flow of the solids through the chemical loop.
RECURRENT TWO-SIDED LOOP-TYPE JETS DUE TO A BIPOLE EMERGING BELOW TRANSEQUATORIAL LOOPS
Jiang, Yunchun; Bi, Yi; Yang, Jiayan; Li, Haidong; Yang, Bo; Zheng, Ruisheng
2013-10-01
We report four successive two-sided loop-type jets centered around a small bipole emerging below transequatorial interconnecting loops (TILs). They occurred at the very first emerging stage of the bipole in a short recurrent period of only 12 minutes. During this term, the emerging flux consisted of a main bipole, but showed a mixed-polarity field morphology with the appearance and then disappearance of a small magnetic feature in its interior. However, no associated cancellation of the bipole with the nearby flux was observed in this process. In multi-wavelength EUV images, the jets started nearly simultaneously and were similar in appearance. Each jet consisted of a pair of components that connected to two bright footpoints around the bipole and were ejected from the emergence location to opposite directions. While the two bright footpoints were separated by a gap and had consistent evolution with that of the bipole, the jet base region covering them accordingly showed four episodes of emission enhancement that peaked approximately at the jet start times. Compatible with the magnetic-reconnection jet mechanism, the recurrent two-sided loop-type jets are explained as a result of reconnection between the emerging bipole and the overlying TILs.
Closed-loop control of anesthesia in children 1 Robust closed-loop control of induction and
: During closed-loop control, a drug infusion is continually adjusted according to a measure of clinical. Remifentanil was administered as a bolus (0.5 g/kg), followed by continuous infusion (0.03 g/kg/min). The propofol infusion was closed-loop controlled throughout induction and maintenance of anesthesia, using
Three-loop Three-Linear Vertices and Four-Loop MOM beta functions in massless QCD
K. G. Chetyrkin; A. Retey
2000-07-10
In this paper we present a full set of 2- and 3-point functions for massless QCD at three-loop order in the MSbar scheme. The vertex functions are evaluated at the asymmetric point with one vanishing momentum. These results are used to relate the MSbar coupling constant to that of various momentum subtraction renormalization schemes at three-loop order. With the help of the known four-loop MS-bar beta-function we then determine the four-loop coefficients of the corresponding MOM beta-functions. As an application we consider the momentum dependence (running) of the three-gluon asymmetrical vertex recently computed within the lattice approach by Ph. Boucaud et al. (JHEP 04 006 (2000)). An account of the four-loop term in the corresponding beta-function leads to a significant (around 30%) decrease of the value of the non-perturbative power-suppressed correction to the running.
Chemical Looping Combustion Reactions and Systems
Sarofim, Adel; Lighty, JoAnn; Smith, Philip; Whitty, Kevin; Eyring, Edward; Sahir, Asad; Alvarez, Milo; Hradisky, Michael; Clayton, Chris; Konya, Gabor; Baracki, Richard; Kelly, Kerry
2014-03-01
Chemical Looping Combustion (CLC) is one promising fuel-combustion technology, which can facilitate economic CO{sub 2} capture in coal-fired power plants. It employs the oxidation/reduction characteristics of a metal, or oxygen carrier, and its oxide, the oxidizing gas (typically air) and the fuel source may be kept separate. This topical report discusses the results of four complementary efforts: (5.1) the development of process and economic models to optimize important design considerations, such as oxygen carrier circulation rate, temperature, residence time; (5.2) the development of high-performance simulation capabilities for fluidized beds and the collection, parameter identification, and preliminary verification/uncertainty quantification; (5.3) the exploration of operating characteristics in the laboratoryscale bubbling bed reactor, with a focus on the oxygen carrier performance, including reactivity, oxygen carrying capacity, attrition resistance, resistance to deactivation, cost and availability; and (5.4) the identification of kinetic data for copper-based oxygen carriers as well as the development and analysis of supported copper oxygen carrier material. Subtask 5.1 focused on the development of kinetic expressions for the Chemical Looping with Oxygen Uncoupling (CLOU) process and validating them with reported literature data. The kinetic expressions were incorporated into a process model for determination of reactor size and oxygen carrier circulation for the CLOU process using ASPEN PLUS. An ASPEN PLUS process model was also developed using literature data for the CLC process employing an iron-based oxygen carrier, and the results of the process model have been utilized to perform a relative economic comparison. In Subtask 5.2, the investigators studied the trade-off between modeling approaches and available simulations tools. They quantified uncertainty in the high-performance computing (HPC) simulation tools for CLC bed applications. Furthermore, they performed a sensitivity analysis for velocity, height and polydispersity and compared results against literature data for experimental studies of CLC beds with no reaction. Finally, they present an optimization space using simple non-reactive configurations. In Subtask 5.3, through a series of experimental studies, behavior of a variety of oxygen carriers with different loadings and manufacturing techniques was evaluated under both oxidizing and reducing conditions. The influences of temperature, degree of carrier conversion and thermodynamic driving force resulting from the difference between equilibrium and system O{sub 2} partial pressures were evaluated through several experimental campaigns, and generalized models accounting for these influences were developed to describe oxidation and oxygen release. Conversion of three solid fuels with widely ranging reactivities was studied in a small fluidized bed system, and all but the least reactive fuel (petcoke) were rapidly converted by oxygen liberated from the CLOU carrier. Attrition propensity of a variety of carriers was also studied, and the carriers produced by freeze granulation or impregnation of preformed substrates displayed the lowest rates of attrition. Subtask 5.4 focused on gathering kinetic data for a copper-based oxygen carrier to assist with modeling of a functioning chemical looping reactor. The kinetics team was also responsible for the development and analysis of supported copper oxygen carrier material.
Heating and cooling of coronal loops observed by SDO
Li, Leping; Chen, Feng; Zhang, Jun
2015-01-01
Context: One of the most prominent processes suggested to heat the corona to well above 10^6 K builds on nanoflares, short bursts of energy dissipation. Aims: We compare observations to model predictions to test the validity of the nanoflare process. Methods: Using extreme UV data from AIA/SDO and HMI/SDO line-of-sight magnetograms we study the spatial and temporal evolution of a set of loops in active region AR 11850. Results: We find a transient brightening of loops in emission from Fe xviii forming at about 7.2 MK while at the same time these loops dim in emission from lower temperatures. This points to a fast heating of the loop that goes along with evaporation of material that we observe as apparent upward motions in the image sequence. After this initial phases lasting for some 10 min, the loops brighten in a sequence of AIA channels showing cooler and cooler plasma, indicating the cooling of the loops over a time scale of about one hour. A comparison to the predictions from a 1D loop model shows that t...
Diesel Combustion Control with Closed-Loop Control of the Injection...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Combustion Control with Closed-Loop Control of the Injection Strategy Diesel Combustion Control with Closed-Loop Control of the Injection Strategy New control strategies are...
TS LOOP NON-POTABLE PUMP EVALUATION
S. Goodin
1999-05-14
This analysis evaluates the existing subsurface non-potable water system from the portal pump to the end of the water line in the South Ramp and determines if the pump size and spacing meets the system pressure and flow requirements for construction operations and incipient fire fighting capability as established in the Subsurface Fire Hazards Analysis (CRWMS M&O 1998b). This analysis does not address the non potable water system in the Cross Drift which is covered under a previous design analysis (CRWMS-M&O 1998a). The Subsurface Fire Hazards Analysis references sections of OSHA 29 CFR 1910 Subpart L for requirements applicable to the incipient fire fighting hose stations used underground. This analysis does not address mechanical system valves, fittings, risers and other components of the system piping. This system is not designed or intended to meet all National Fire Protection Association (NFPA) codes for a fire fighting system but is only considered a backup system to fire extinguishers that are installed throughout the Topopah Springs (TS) Loop and may be used to fight small incipient stage fires.
Fiber-bragg grating-loop ringdown method and apparatus
Wang, Chuji
2008-01-29
A device comprising a fiber grating loop ringdown (FGLRD) system of analysis is disclosed. A fiber Bragg grating (FBG) or Long-Period grating (LPG) written in a section of single mode fused silica fiber is incorporated into a fiber loop. By utilizing the wing areas of the gratings' bandwidth as a wavelength dependent attenuator of the light transmission, a fiber grating loop ringdown concept is formed. One aspect of the present invention is temperature sensing, which has been demonstrated using the disclosed device. Temperature measurements in the areas of accuracy, stability, high temperature, and dynamic range are also described.
ORNL/TM-2008/048 Uranyl Nitrate Flow Loop
Pennycook, Steve
ORNL/TM-2008/048 Uranyl Nitrate Flow Loop October 2008 Jennifer L. Ladd-Lively #12;DOCUMENT Government or any agency thereof. #12;ORNL/TM-2008/048 Nuclear Science and Technology Division URANYL NITRATE
HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA
Brooks, David H.; Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Winebarger, Amy R. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States)
2013-08-01
Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.
Closed-loop real-time control on distributed networks
Ambike, Ajit Dilip
2004-11-15
This thesis is an e?ort to develop closed-loop control strategies on computer networks and study their stability in the presence of network delays and packet losses. An algorithm using predictors was designed to ...
Standing Slow MHD Waves in Radiatively Cooling Coronal Loops
Al-Ghafri, Khalil Salim
2015-01-01
The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops namely thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function that ensures the temperature evolution of the background plasma due to radiation coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglect the magnetic field perturbation and eventually reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale much larger than the oscillation period that subsequently enables...
Experimental characterization and chemical kinetics study of chemical looping combustion
Chen, Tianjiao, S.M. Massachusetts Institute of Technology
2014-01-01
Chemical looping combustion (CLC) is one of the most promising technologies to achieve carbon capture in fossil fuel power generation plants. A novel rotary-bed reactor concept was proposed by Zhao et. al. [1] in 2013. It ...
Seismology of transversely oscillating coronal loops with siphon flows
Terradas, J; Verth, G; Goossens, M
2011-01-01
There are ubiquitous flows observed in the solar atmosphere of sub-Alfv\\'{e}nic speeds, however after flaring and coronal mass ejection events flows can become Alfv\\'{e}nic. In this Letter, we derive an expression for the standing kink mode frequency due to siphon flow in coronal loops, valid for both low and high speed regimes. It is found that siphon flow introduces a linear spatially dependent phase shift along coronal loops and asymmetric eigenfunctions. We demonstrate how this theory can be used to determine the kink and flow speed of oscillating coronal loops with reference to an observational case study. It is shown that the presence of siphon flow can cause the underestimation of magnetic field strength in coronal loops using the traditional seismological methods.
Enhanced Ultraviolet Cancellations in N = 5 Supergravity at Four Loop
Zvi Bern; Scott Davies; Tristan Dennen
2014-09-09
We show that the four-loop four-point amplitudes of N = 5 supergravity are ultraviolet finite in four dimensions, contrary to expectations based on supersymmetry and duality-symmetry arguments. We explain why the diagrams of any covariant local formalism cannot manifestly exhibit the necessary cancellations for finiteness but instead require a new type of nontrivial ultraviolet cancellation that we call "enhanced cancellations". We also show that the three-loop four-point amplitudes in N = 4 and N = 5 supergravity theories display enhanced cancellations. To construct the loop integrand, we use the duality between color and kinematics. We apply standard methods for extracting ultraviolet divergences in conjunction with the FIRE5 integral reduction program to arrive at the four-loop results.
Mechanisms Engineering Test Loop - Phase I Status Report - FY2015
Hvasta, M.; Grandy, C.; Lisowski, D.; Borowski, A.
2015-09-01
This report documents the current status of the Mechanisms Engineering Test Loop (METL) as of the end of FY2015. METL is currently in Phase I of its design and construction.
MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE
MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE HEAT PUMP SYSTEMS By CENK SOURCE HEAT PUMP SYSTEMS Thesis Approved: ___________________________________________ Thesis Adviser pump systems. For detailed analysis and accurate simulation of the transient heat transfer in vertical
Klystron "efficiency loop" for the ALS storage ring RF system
Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth
2002-01-01
to Mod, Feb. 7, 2002] SRRF Klystron Beam Current (A) [AfterTime (hrs) Figure 2: SRRF Klystron Efficiency Comparison forKLYSTRON “EFFICIENCY LOOP” FOR THE ALS STORAGE RING RF
Klystron 'efficiency loop' for the ALS storage ring RF system
Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth
2002-05-20
The recent energy crisis in California has led us to investigate the high power RF systems at the Advanced Light Source (ALS) in order to decrease the energy consumption and power costs. We found the Storage Ring Klystron Power Amplifier system operating as designed but with significant power waste. A simple proportional-integrator (PI) analog loop, which controls the klystron collector beam current, as a function of the output RF power, has been designed and installed. The design considerations, besides efficiency improvement, were to interface to the existing system without major expense. They were to also avoid the klystron cathode power supply filter's resonance in the loop's dynamics, and prevent a conflict with the existing Cavity RF Amplitude Loop dynamics. This efficiency loop will allow us to save up to 700 MW-hours of electrical energy per year and increase the lifetime of the klystron.
Three dimensional instability of flexible ferromagnetic filament loop
K. ?rglis; R. Livanovi?s; A. C?bers
2010-09-07
Dynamics of flexible ferromagnetic filaments in an external magnetic field is considered. We report the existence of a buckling instability of the ferromagnetic filament at the magnetic field reversion, which leads to the formation of a metastable loop. Its relaxation through three dimensional transformation of the configurations is observed experimentally and confirmed by numerical simulations. Bending modulus of the flexible ferromagnetic filaments synthesized by linking micron size core-shell ferromagnetic particles with DNA fragments is estimated by comparison of the parameters of the loops observed in the experiment with theoretical calculations. Formation of the loop and its relaxation are characterized by the numerically calculated writhe number. The relaxation time of the loop allows us to estimate the hydrodynamic drag of the filament.
Tachyon condensation in boundary string field theory at one loop
K. Bardakci; A. Konechny
2001-08-21
We compute the one-loop partition function for quadratic tachyon background in open string theory. Both closed and open string representations are developed. Using these representations we study the one-loop divergences in the partition function in the presence of the tachyon background. The divergences due to the open and closed string tachyons are treated by analytic continuation in the tachyon mass squared. We pay particular attention to the imaginary part of the analytically continued expressions. The last one gives the decay rate of the unstable vacuum. The dilaton tadpole is also given some partial consideration. The partition function is further used to study corrections to tachyon condensation processes describing brane descent relations. Assuming the boundary string field theory prescription for construction of the string field action via partition function holds at one loop level we study the one-loop corrections to the tachyon potential and to the tensions of lower-dimensional branes.
Quantum reduced loop gravity: extension to scalar field
Jakub Bilski; Emanuele Alesci; Francesco Cianfrani
2015-07-02
The quantization of the Hamiltonian for a scalar field is performed in the framework of Quantum Reduced Loop Gravity. We outline how the regularization can be performed by using the analogous tools adopted in full Loop Quantum Gravity and the matrix elements of the resulting operator between basis states are analytic coefficients. These achievements open the way for a consistent analysis of the Quantum Gravity corrections to the classical dynamics of gravity in the presence of a scalar field in a cosmological setting.
Entropy and Area of Black Holes in Loop Quantum Gravity
I. B. Khriplovich
2002-03-31
Simple arguments related to the entropy of black holes strongly constrain the spectrum of the area operator for a Schwarzschild black hole in loop quantum gravity. In particular, this spectrum is fixed completely by the assumption that the black hole entropy is maximum. Within the approach discussed, one arrives in loop quantum gravity at a quantization rule with integer quantum numbers $n$ for the entropy and area of a black hole.
Tree-Loop Duality Relation beyond simple poles
Isabella Bierenbaum; Sebastian Buchta; Petros Draggiotis; Ioannis Malamos; German Rodrigo
2012-11-21
We develop the Tree-Loop Duality Relation for two- and three-loop integrals with multiple identical propagators (multiple poles). This is the extension of the Duality Relation for single poles and multiloop integrals derived in previous publications. We prove a generalization of the formula for single poles to multiple poles and we develop a strategy for dealing with higher-order pole integrals by reducing them to single pole integrals using Integration By Parts.
Determination of the Coronal Magnetic Field by Hot Loop Oscillations
Tongjiang Wang; Davina E. Innes; Jiong Qiu
2006-12-20
We apply a new method to determine the magnetic field in coronal loops using observations of coronal loop oscillations. We analyze seven Doppler shift oscillation events detected by SUMER in the hot flare line Fe XIX to obtain oscillation periods of these events. The geometry, temperature, and electron density of the oscillating loops are measured from coordinated multi-channel soft X-ray imaging observations from SXT. All the oscillations are consistent with standing slow waves in their fundamental mode. The parameters are used to calculate the magnetic field of coronal loops based on MHD wave theory. For the seven events, the plasma $\\beta$ is in the range 0.15-0.91 with a mean of 0.33$\\pm$0.26, and the estimated magnetic field varies between 21-61 G with a mean of 34$\\pm$14 G. With background emission subtracted, the estimated magnetic field is reduced by 9%-35%. The maximum backgroud subtraction gives a mean of 22$\\pm$13 G in the range 12-51 G. We discuss measurement uncertainties and the prospect of determining coronal loop magnetic fields from future observations of coronal loops and Doppler shift oscillations.
Triple loop heat exchanger for an absorption refrigeration system
Reimann, Robert C. (Lafayette, NY)
1984-01-01
A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.
Antusch, Stefan
2015-01-01
The renormalization group (RG) running of the neutrino mass operator is required for comparing the predictions of neutrino models at high energy with the experimental data at low energies. In the type I seesaw scenario with n_G right-handed neutrinos, the RG running is also performed in the effective theories above and between the thresholds given by the masses of the right-handed neutrinos. At these thresholds, the effective theories are matched. When calculating the two-loop RG running, the matching has to be performed at the one-loop level. In this work, we calculate the one-loop matching formulae in the MSSM extended by n_G right-handed neutrinos using supergraph techniques. Moreover we present a general formula for one-loop matching of superpotential operators which can readily be applied to any supersymmetric theory where chiral superfields are integrated out.
Micro-Columnated Loop Heat Pipe: The Future of Electronic Substrates
Dhillon, Navdeep Singh
2012-01-01
Loop Heat Pipes . . . . . . . . . . . . . . . . . . . .Heat Pipes . . . . . . . . . . . . . . . . . . . . . . . .of operation of a heat pipe [13]. . . . . . . . . . . . . .
The Loop Current may not have protected South Florida this year Rejoined to
Meyers, Steven D.
this year. In fact, if the oil was spilling right now, the Loop Cur- rent would be doing just what experts complete Rejoined to loop current Site of oil spill The Loop Current, so-called because it loops through, to the heart of offshore oil fields. The Gulf of Mexico is not a flat body of water. Though the eye can
An Innovative Pressure Sensor Glow Plug Offers Improved Diesel Engine Closed-loop Control
Broader source: Energy.gov [DOE]
Describes glow plug with integrated pressure sensor for closed-loop control of diesel engine combustion
Ross, Joseph
frictionless coaster car. She is initially propelled with speed vo towards the loop, then she coasts around the circular track, of diameter 10.0 m. Freida and her car have total mass 120 kg. (a) If her initial speed (vo) is 20 m/s, determine the speed at the top of the loop. (b) Draw free-body diagrams for the coaster car
of high efficiency operational processes, interest in chemical looping technology has resurfaced for itsThe concept of chemical looping reactions has been widely applied in chemical industries. Fundamental research on chemical looping reactions has also been applied to energy systems. Fossil fuel
Haihua Zhao; Hongbin Zhang; Samuel E. Bays
2009-05-01
The sodium intermediate heat transfer loop is used in existing sodium cooled fast reactor (SFR) plant design as a necessary safety measure to separate the radioactive primary loop sodium from the water of the steam Rankine power cycle. However, the intermediate heat transfer loop significantly increases the SFR plant cost and decreases the plant reliability due to the relatively high possibility of sodium leakage. A previous study shows that helium Brayton cycles with multiple reheat and intercooling for SFRs with reactor outlet temperature in the range of 510°C to 650°C can achieve thermal efficiencies comparable to or higher than steam cycles or recently proposed supercritical CO2 cycles. Use of inert helium as the power conversion working fluid provides major advantages over steam or CO2 by removing the requirement for safety systems to prevent and mitigate the sodium-water or sodium-CO2 reactions. A helium Brayton cycle power conversion system therefore makes the elimination of the intermediate heat transfer loop possible. This paper presents a pre-conceptual design of multiple reheat helium Brayton cycle for an advanced loop type SFR. This design widely refers the new horizontal shaft distributed PBMR helium power conversion design features. For a loop type SFR with reactor outlet temperature 550°C, the design achieves 42.4% thermal efficiency with favorable power density comparing with high temperature gas cooled reactors.
Radiation Hardness Testing of Materials at the UC Davis/ McClellan Nuclear Radiation Center
Boussoufi, M.; Steingass, W.; Shiraki, R.; Liu, H. B.; Flocchini, R.
2006-01-01
shield Exposure vessel CONDITIONING WELL… • The conditioning well is installed adjacent to the annular graphite reflector inside the reactor tank. •
System design description for GCFR-core flow test loop
Huntley, W.R.; Grindell, A.G.
1980-12-01
The Core Flow Test Loop is a high-pressure, high-temperature, out-of-reactor helium circulation system that is being constructed to permit detailed study of the thermomechanical and thermal performance at prototypic steady-state and transient operating conditions of simulated segments of core assemblies for a GCFR Demonstration Plant, as designed by General Atomic Company. It will also permit the expermental verification of predictive analytical models of the GCFR core assemblies needed to reduce operational and safety uncertainties of the GCFR. Full-sized blanket assemblies and segments of fuel rod and control rod fuel assemblies will be simulated with test bundles of electrically powered fuel rod or blanket rod simulators. The loop will provide the steady-state and margin test requirements of bundle power and heat removal, and of helium coolant flow rate, pressure, and temperature for test bundles having up to 91 rods; these requirements set the maximum power, coolant helium flow, and thermal requirements for the loop. However, the size of the test vessel that contains the test bundles will be determined by the bundles that simulate a full-sized GCFR blanket assembly. The loop will also provide for power and coolant transients to simulate transient operation of GCFR core assemblies, including the capability for rapid helium depressurization to simulate the depressurization class of GCFR accidents. In addition, the loop can be used as an out-of-reactor test bed for characterizing in-reactor test bundle configurations.
The massless higher-loop two-point function
Francis Brown
2008-04-10
We introduce a new method for computing massless Feynman integrals analytically in parametric form. An analysis of the method yields a criterion for a primitive Feynman graph $G$ to evaluate to multiple zeta values. The criterion depends only on the topology of $G$, and can be checked algorithmically. As a corollary, we reprove the result, due to Bierenbaum and Weinzierl, that the massless 2-loop 2-point function is expressible in terms of multiple zeta values, and generalize this to the 3, 4, and 5-loop cases. We find that the coefficients in the Taylor expansion of planar graphs in this range evaluate to multiple zeta values, but the non-planar graphs with crossing number 1 may evaluate to multiple sums with $6^\\mathrm{th}$ roots of unity. Our method fails for the five loop graphs with crossing number 2 obtained by breaking open the bipartite graph $K_{3,4}$ at one edge.
Automated event generation for loop-induced processes
Hirschi, Valentin
2015-01-01
We present the first fully automated implementation of cross-section computation and event generation for loop-induced processes. This work is integrated in the MadGraph5_aMC@NLO framework. We describe the optimisations implemented at the level of the matrix element evaluation, phase space integration and event generation allowing for the simulation of large multiplicity loop-induced processes. Along with some selected differential observables, we illustrate our results with a table showing inclusive cross-sections for all loop-induced hadronic scattering processes with up to three final states in the SM as well as for some relevant two to four processes. Many of these are computed here for the first time.
Automated event generation for loop-induced processes
Valentin Hirschi; Olivier Mattelaer
2015-09-29
We present the first fully automated implementation of cross-section computation and event generation for loop-induced processes. This work is integrated in the MadGraph5_aMC@NLO framework. We describe the optimisations implemented at the level of the matrix element evaluation, phase space integration and event generation allowing for the simulation of large multiplicity loop-induced processes. Along with some selected differential observables, we illustrate our results with a table showing inclusive cross-sections for all loop-induced hadronic scattering processes with up to three final states in the SM as well as for some relevant two to four processes. Many of these are computed here for the first time.
Loop-induced Neutrino Masses: A Case Study
Geng, Chao-Qiang; Tsai, Lu-Hsing
2014-01-01
We study the cocktail model in which the Majorana neutrino masses are generated by the so-called "cocktail" three-loop diagrams with the dark matter particle running in the loops. In particular, we give the correct analytic expressions of the neutrino masses in the model by the detailed calculation of the cocktail diagrams. Based on the reliable numerical calculation of the loop integrals, we explore the parameter space which can give the correct orders of neutrino masses while satisfying other experimental constraints, such as those from the neutrinoless double beta decay, low-energy lepton flavor violation processes, electroweak precision tests, and collider searches. As a result, the large couplings and the large mass difference between the two singly-charged (neutral) scalars are required.
Expansion-loop enclosure resolves subsea line problems
Rich, S.K.; Alleyne, A.G.
1998-08-03
Recent design and construction of a Gulf of Mexico subsea pipeline illustrate the use of buried, enclosed expansion loops to resolve problems from expansion and upheaval buckling. Buried, subsea pipelines operating at high temperatures and pressures experience extreme compressive loads caused by the axial restraint of the soil. The high axial forces combined with imperfections in the seabed may overstress the pipeline or result in upheaval buckling. Typically, expansion loops, or doglegs, are installed to protect the pipeline risers from expansion and to alleviate axial forces. Buried expansion loops, however, are rendered virtually ineffective by the lateral restraint of the soil. Alternative methods to reduce expansion may increase the potential of upheaval buckling or overstressing the pipeline. Therefore, system design must consider expansion and upheaval buckling together. Discussed here are methods of prevention and control of expansion and upheaval buckling, evaluating the impact on the overall system.
From Classical To Quantum Gravity: Introduction to Loop Quantum Gravity
Kristina Giesel; Hanno Sahlmann
2013-01-02
We present an introduction to the canonical quantization of gravity performed in loop quantum gravity, based on lectures held at the 3rd quantum geometry and quantum gravity school in Zakopane in 2011. A special feature of this introduction is the inclusion of new proposals for coupling matter to gravity that can be used to deparametrize the theory, thus making its dynamics more tractable. The classical and quantum aspects of these new proposals are explained alongside the standard quantization of vacuum general relativity in loop quantum gravity.
Path Integral of Bianchi I models in Loop Quantum Cosmology
Xiao Liu; Fei Huang; Jian-Yang Zhu
2013-02-01
A path integral formulation of the Bianchi I models containing a massless scalar field in loop quantum cosmology is constructed. Following the strategy used in the homogenous and isotropic case, the calculation is extended to the simplest non-isotropic models according to the $\\bar{\\mu}$ and $\\bar{\\mu}^{\\prime}$ scheme. It is proved from the path integral angle that the quantum dynamic lacks the full invariance with respect to fiducial cell scaling in the $\\bar{\\mu}$ scheme, but it does not in the $\\bar{\\mu}^{\\prime}$ scheme. The investigation affirms the equivalence of the canonical approach and the path integral approach in loop quantum cosmology.
Loop formulation of supersymmetric Yang-Mills quantum mechanics
Kyle Steinhauer; Urs Wenger
2014-10-01
We derive the fermion loop formulation of N=4 supersymmetric SU(N) Yang-Mills quantum mechanics on the lattice. The loop formulation naturally separates the contributions to the partition function into its bosonic and fermionic parts with fixed fermion number and provides a way to control potential fermion sign problems arising in numerical simulations of the theory. Furthermore, we present a reduced fermion matrix determinant which allows the projection into the canonical sectors of the theory and hence constitutes an alternative approach to simulate the theory on the lattice.
String Loop Corrections to Stable Non-BPS Branes
N. D. Lambert; I. Sachs
2000-10-31
We calculate the string loop corrections to the tachyon potential for stable non-BPS Dp-branes on the orbifold T^4/Z_2. We find a non-trivial phase structure and we show that, after tachyon condensation, the non-BPS Dp-branes are attracted to each other for p=0,1,2. We then identify the corresponding closed string boundary states together with the massless long range fields they excite. For p=3,4 the string loop correction diverge. We identify the massless closed string fields responsible for these divergencies and regularise the partition function using a Fischler-Susskind mechanism.
One-Loop Soft Theorems via Dual Superconformal Symmetry
Brandhuber, Andreas; Spence, Bill; Travaglini, Gabriele
2015-01-01
We study soft theorems at one loop in planar N=4 super Yang-Mills theory through finite order in the infrared regulator and to subleading order in the soft parameter {\\delta}. In particular, we derive a universal constraint from dual superconformal symmetry, which we use to bootstrap subleading log {\\delta} behaviour. Moreover, we determine the complete infrared-finite subleading soft contribution of n-point MHV amplitudes using momentum twistors. Finally, we compute the subleading log {\\delta} behaviour of one-loop NMHV ratio functions at six and seven points, finding that universality holds within but not between helicity sectors.
Martinez-Guridi, G.; Samanta, P.; Chu, L.; Yang, J.
1998-08-01
A loss-of-coolant accident (LOCA) can cause a loss-of-offsite power (LOOP) wherein the LOOP is usually delayed by few seconds or longer. Such an accident is called LOCA with consequential LOOP, or LOCA with delayed LOOP (here, abbreviated as LOCA/LOOP). This paper analyzes the unique conditions that are associated with a LOCA/LOOP, presents a model, and quantifies its contribution to core damage frequency (CDF). The results show that the CDF contribution can be a dominant contributor to risk for certain plant designs, although boiling water reactors (BWRs) are less vulnerable than pressurized water reactors (PWRs).
G. Belanger; F. Boudjema; J. Fujimoto; T. Ishikawa; T. Kaneko; K. Kato; Y. Shimizu
2006-04-18
We describe the main building blocks of a generic automated package for the calculation of Feynman diagrams. These blocks include the generation and creation of a model file, the graph generation, the symbolic calculation at an intermediate level of the Dirac and tensor algebra, implementation of the loop integrals, the generation of the matrix elements or helicity amplitudes, methods for the phase space integrations and eventually the event generation. The report focuses on the fully automated systems for the calculation of physical processes based on the experience in developing GRACE-loop. As such, a detailed description of the renormalisation procedure in the Standard Model is given emphasizing the central role played by the non-linear gauge fixing conditions for the construction of such automated codes. The need for such gauges is better appreciated when it comes to devising efficient and powerful algorithms for the reduction of the tensorial structures of the loop integrals. A new technique for these reduction algorithms is described. Explicit formulae for all two-point functions in a generalised non-linear gauge are given, together with the complete set of counterterms. We also show how infrared divergences are dealt with in the system. We give a comprehensive presentation of some systematic test-runs which have been performed at the one-loop level for a wide variety of two-to-two processes to show the validity of the gauge check. These cover fermion-fermion scattering, gauge boson scattering into fermions, gauge bosons and Higgs bosons scattering processes. Comparisons with existing results on some one-loop computation in the Standard Model show excellent agreement. We also briefly recount some recent development concerning the calculation of mutli-leg one-loop corrections.
A Radiation Tolerant Phase Locked Loop Design for Digital Electronics
Kumar, Rajesh
2011-10-21
oscillator (VCO), the phase frequency detector (PFD) and the charge pump/loop filter-are designed in a radiation tolerant manner. Whenever possible, the circuit elements used in our PLL exploit the fact that if a gate is implemented using only PMOS (NMOS...
Closed-Loop Energy Management Control of Large Industrial Facilities
Childress, R. L.
2002-01-01
providing steam to the process. A Sell Advisor calculates Make-Buy decisions based on real-time electrical prices, fuel prices and boiler loads. Condensing turbines are coordinated with closed-loop control to provide the lowest energy cost to the plant. When...
Conformal Behavior at Four Loops and Scheme (In)Dependence
Thomas A. Ryttov
2014-10-01
We search for infrared zeros of the beta function and evaluate the anomalous dimension of the mass at the associated fixed point for asymptotically free vector-like fermionic gauge theories with gauge group SU(N). The fixed points of the beta function are studied at the two, three and four loop level in two different explicit schemes. These are the modified regularization invariant, RI', scheme and the minimal momentum subtraction, mMOM, scheme. The search is performed in Landau gauge where the beta function of the gauge parameter vanishes. We then compare our findings to earlier identical investigations performed in the modified minimal subtraction, $\\bar{\\text{MS}}$, scheme. It is found that the value of the anomalous dimension of the mass is smaller at three and four loops than at two loops. This seems to be a generic pattern that is observed in all three different schemes. We then estimate the value of the anomalous dimension to be $\\gamma \\sim 0.225-0.375$ for twelve fundamental flavors and three colors, $\\gamma \\sim 0.500 - 0.593$ for two adjoint flavors and two colors and finally $\\gamma \\sim 1.12-1.70$ for two two-indexed flavors and three colors with the lower and upper bound set by the minimum and maximum value respectively over all three schemes and at three and four loops. Our analysis suggests that the former two theories lie in the conformal window while the latter belongs to the chirally broken phase.
Combined Loop Transformation and Hierarchy Allocation for Data Reuse Optimization
Cong, Jason "Jingsheng"
transformation framework was established based on parametric integer linear programming [6-8]. Data dependenceCombined Loop Transformation and Hierarchy Allocation for Data Reuse Optimization Jason Cong, Peng Zhang, Yi Zou Computer Science Department University of California, Los Angeles Los Angeles, CA 90095
MODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE
exchanger model is crucial for analysis of hybrid ground source heat pump systems. Ground source heat pumps in a hybrid ground source heat pump application under different climate conditions. An actual office buildingMODELING OF VERTICAL GROUND LOOP HEAT EXCHANGERS FOR GROUND SOURCE HEAT PUMP SYSTEMS By CENK
FUSION OF HAMILTONIAN LOOP GROUP MANIFOLDS AND COBORDISM
Woodward, Christopher
FUSION OF HAMILTONIAN LOOP GROUP MANIFOLDS AND COBORDISM E. MEINRENKEN AND C. WOODWARD Abstract. We References 32 1. Introduction Let G be a compact, connected, simply connected, simple Lie group and \\Sigma. In a sequel [15] to this paper, we apply our method to compute the coefficients of the fusion ring (Verlinde
Automation of Multi-leg One-loop virtual Amplitudes
D. Maitre
2010-06-29
In the last few years, much progress has been made in the computation of one-loop virtual matrix elements for processes involving many external particles. In this contribution the methods that have enabled this recent progress are briefly reviewed with a focus on their computing and automation aspects.
EIS-0417: South Mountain Freeway (Loop 202); Phoenix, Arizona
Broader source: Energy.gov [DOE]
Federal Highway Administration and Arizona Department of Transportation, with Western Area Power Administration as a cooperating agency, prepared an EIS that analyzes the potential environmental impacts of the proposed South Mountain Freeway (Loop 202) project in the Greater Metropolitan Phoenix Area.
Bootstrapping Multi-Parton Loop Amplitudes in QCD
Bern, Zvi; /UCLA; Dixon, Lance J.; /SLAC; Kosower, David A.; /Saclay, SPhT
2005-07-06
The authors present a new method for computing complete one-loop amplitudes, including their rational parts, in non-supersymmetric gauge theory. This method merges the unitarity method with on-shell recursion relations. It systematizes a unitarity-factorization bootstrap approach previously applied by the authors to the one-loop amplitudes required for next-to-leading order QCD corrections to the processes e{sup +}e{sup -} {yields} Z, {gamma}* {yields} 4 jets and pp {yields} W + 2 jets. We illustrate the method by reproducing the one-loop color-ordered five-gluon helicity amplitudes in QCD that interfere with the tree amplitude, namely A{sub 5;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}) and A{sub 5;1}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup +}). Then we describe the construction of the six- and seven-gluon amplitudes with two adjacent negative-helicity gluons, A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}) and A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), which uses the previously-computed logarithmic parts of the amplitudes as input. They present a compact expression for the six-gluon amplitude. No loop integrals are required to obtain the rational parts.
ORIGINAL ARTICLE Comparative genomics-guided loop-mediated isothermal
Hsiang, Tom
ORIGINAL ARTICLE Comparative genomics-guided loop-mediated isothermal amplification sequencing and analytical techniques, genomic sequence data of prok- aryotes are accumulating at a very rapid pace. As of October 2008, there are 873 complete and pub- lished genome sequences, as well as 2025
Complete Two-Loop Corrections to H -> gamma gamma
Giampiero Passarino; Christian Sturm; Sandro Uccirati
2007-07-10
In this paper the complete two-loop corrections to the Higgs-boson decay, H -> gamma gamma, are presented. The evaluations of both QCD and electroweak corrections are based on a numerical approach. The results cover all kinematical regions, including the WW normal-threshold, by introducing complex masses in the relevant (gauge-invariant) parts of the LO and NLO amplitudes.
Complete three-loop QCD corrections to the decay H -> ??
P. Maierhöfer; P. Marquard
2012-12-26
We present the result for the three-loop singlet QCD corrections to the decay of a Higgs boson into two photons and improve the calculation for the non-singlet case. With the new result presented, the decay width Gamma(H -> \\gamma \\gamma) is completely known at O(G_F \\alpha ^2 \\alpha_s^2, G_F \\alpha ^3).
Into the Loops: Practical Issues in Translation Validation for
Barrett, Clark W.
optimizations employed by Intel's ORC compiler. Tvoc, however, is somewhat limited when dealing with loop ORC, this instrumentation is fortu- nately part of the compiler). This paper addresses all the issues by the Intel ORC compiler, describes a methodology for translation validation in the presence of combinations
DIFFUSION INDUCED CHAOS IN A CLOSED LOOP THERMOSYPHON
Van Vleck, Erik S.
VLECK SIAM J. APPL. MATH. c 1998 Society for Industrial and Applied Mathematics Vol. 58, No. 4, pp. 1072 a prescribed heat flux along the loop wall and the contribution of axial diffusion. The well, driven by gravity, natural convection, pumps, etc. These types of devices are called ther- mosyphons
Multiprotein DNA Looping Jose M. G. Vilar* and Leonor Saiz
Saiz, Leonor
symmetric counterpart on the other operator if DNA is looped. The typical way to obtain the statistical, and telomere maintenance. DOI: 10.1103/PhysRevLett.96.238103 PACS numbers: 87.14.Gg, 05.50.+q, 87.15.He, 87 [7], replication [4], and telomere maintenance [8]. Disruption or alteration of these processes often
Loop invariants on demand K. Rustan M. Leino0
Leino, K. Rustan M.
a dynamic and automatic form of value-based trace partitioning. Finally, the technique can be incorporated on the data (as is done in predicate abstraction [20]) and summaries of the effects of certain control paths (like loop invariants [18,24]). A trend that has emerged in the last decade is to start with coarse
On the q-quantum gravity loop algebra
Seth Major
2008-02-19
A class of deformations of the q-quantum gravity loop algebra is shown to be incompatible with the combinatorics of Temperley-Lieb recoupling theory with deformation parameter at a root of unity. This incompatibility appears to extend to more general deformation parameters.
Closing the Learning-Planning Loop with Predictive State Representations
Guestrin, Carlos
Closing the Learning-Planning Loop with Predictive State Representations Byron Boots Machine and sta- tistically consistent spectral algorithm for learning the pa- rameters of a Predictive State the essential features of the environment. This representation allows accurate prediction with a small number
Opening the Loops -Towards Semantic, Information-centric Networking
Opening the Loops - Towards Semantic, Information-centric Networking in the Internet of Things}@comsys.rwth-aachen.de Abstract--The advent of the Internet of Things (IoT) paradigm in increasing deployments promises and distributed implementation of the proposed infrastructure. I. INTRODUCTION The vision of an Internet of Things
Meson Decays with Isospin Breaking at Two Loops
Lunds Universitet,
-loop quantum cor- rections. The low energy constants of order p6 are estimated by means of a resonance chiral's notes Number of pages 137 Price Security class Distributor Karim Ghorbani Department of Theoretical Physics (IPM-LHP06), Tehran, Iran, 15-20 May 2006, pp 0009. i Johan Bijnens, Niclas Danielsson, Karim
An evaluation of inductance loop detector lead length and optimal speed trap distance
Hamm, Robert Alan
1994-01-01
component of freeway management systems is the inductance loop detector. This research effort evaluated the use of inductance loop detectors in a freeway management situation to determine maximum permissible lead lengths and an optimal speed trap distance...
SU(2) Lattice Gauge Theory- Local Dynamics on Non-intersecting Electric flux Loops
Ramesh Anishetty; Indrakshi Raychowdhury
2014-11-12
We use Schwinger Bosons as prepotentials for lattice gauge theory to de?ne local linking oper- ators and calculate their action on linking states for 2 + 1 dimensional SU(2) lattice gauge theory. We develop a diagrammatic technique and associate a set of (lattice Feynman) rules to compute the entire loop dynamics diagrammatically. The physical loop space is shown to contain only non- intersecting loop con?gurations after solving the Mandelstam constraint. The smallest plaquette loops are contained in the physical loop space and other con?gurations are generated by the action of a set of fusion operators on this basic loop states enabling one to charaterize any arbitrary loop by the basic plaquette together with the fusion variables. Consequently, the full Kogut-Susskind Hamiltonian and the dynamics of all possible non-intersecting physical loops are formulated in terms of these fusion variables.
SIMULATION AND VALIDATION OF HYBRID GROUND SOURCE AND WATER-LOOP HEAT PUMP
SIMULATION AND VALIDATION OF HYBRID GROUND SOURCE AND WATER-LOOP HEAT PUMP SYSTEMS By JASON EARL AND VALIDATION OF HYBRID GROUND SOURCE AND WATER-LOOP HEAT PUMP SYSTEMS Thesis Approved: Dr. Jeffrey D. Spitler
High Performance Loop Filter Design for Continuous-time Sigma-delta ADC
Gui, Fan
2014-11-12
Continuous-time (CT) sigma-delta (??) analog-to-digital converters (ADCs) are widely used in wireless transceiver. Loop filter becomes a critical component in the implementation of high resolution large bandwidth CT ?? ADC because it determines loop...
Development of a Water Loop Simulation at the Texas A&M University Main Campus
Xue, H.; Deng, S.; Claridge, D. E.; Liu, M.
2000-01-01
A computer simulation model is an economic and convenient tool to perform analysis of chilled water loop. The primary objective of this paper is developing procedure for simulating and optimizing chilled water loop with computer simulation model. A...
Why and how to use a differential equation method to calculate multi-loop integrals
M. Czachor; H. Czyz
2001-10-26
A short pedagogical introduction to a differential method used to calculate multi-loop scalar integrals is presented. As an example it is shown how to obtain, using the method, large mass expansion of the two loop sunrise master integrals.
Real Time (20 Second) Data Base Single Loop (Packed into 3 bytes)
) Data Base Single Loop (Packed into 3 bytes) ------------------------------------------- Data Element;------------------------------------------------------------------------- --- Real Time (20 Second) Data Base Station (Packed into 3 bytes Loops | 3 | [0]|Data Present, 0=No Data | |Scan Cnt| 11 | [0]|
Webb, Glenn Viktor
1995-01-01
and/or revolute joints. An open loop system consisting of n bars suspended vertically from a pivot is used to study (1) the effect of the number of degrees of freedom and the Schur complement on the convergence of the Lagrange multipliers...
RELAP-7: Demonstrating the integration of two-phase flow components for an ideal BWR loop
Hongbin Zhang; Haihua Zhao; Ling Zou; David Andrs; John Peterson; Ray Berry; Richard Martineua
2013-06-01
This is DOE Level 3 milestone report documenting RELAP-7's capability to simulate an ideal BWR loop.
Systems Using Hardware-in-the-Loop (Poster) Lundstrom, B.; Shirazi...
Office of Scientific and Technical Information (OSTI)
HARDWARE; LOOP; POSTER; Buildings; Electricity, Resources, and Buildings Systems; Solar Energy - Thermal ELECTRICITY; GRID; ICS; INTERCONNECTION; SYSTEM; EVALUATOR;...
Vanajakshi, Lelitha Devi
2005-11-01
., or from indirect methods such as loop detectors. Because of their wide spread deployment, travel time estimation from loop detector data is one of the most widely used methods. However, the major criticism about loop detector data is the high probability...
Effective SU(2) Polyakov Loop Theories with Heavy Quarks on the Lattice
Philipp Scior; David Scheffler; Dominik Smith; Lorenz von Smekal
2014-12-22
We compare SU(2) Polyakov loop models with different effective actions with data from full two-color QCD simulations around and above the critical temperature. We then apply the effective theories at finite temperature and density to extract quantities like Polyakov loop correlators, effective Polyakov loop potentials and baryon density.
The Astrophysical Journal Submitted, 2000 August 7 Modeling of Coronal EUV Loops Observed with TRACE
Hudson, Hugh
measure distribution peaks in the temperature range of 3Â5 MK, an overwhelming large number of EUV loops loops and transient brightenings. Subject headings: Sun: Corona --- Sun : Active Regions --- Sun : EUV to the interpretation of EUV loops, for which physical parameters such as density n e (s) and temperature T (s) along
Closed-Loop Compensation Method for Oscillations Caused by Control Valve Stiction
Wang, Jiandong
Closed-Loop Compensation Method for Oscillations Caused by Control Valve Stiction Jiandong Wang-loop compensation method to remove oscillations caused by control valve stiction. With the control loop operating movements for the control valve to arrive at a desired position. A systematic way to design the parameters
Planning for ClosedLoop Execution Using Partially Observable Markovian Decision Processes
Chrisman, Lonnie
Planning for ClosedLoop Execution Using Partially Observable Markovian Decision Processes Lonnie@cs.cmu.edu Abstract A distinction is drawn between openloop and closedloop plans, where the latter explicitly spec ifies how runtime feedback is to be acquired and used. It is argued that some planning problems
Laboratory simulations of astrophysical jets and solar coronal loops: new results
Bellan, Paul M.
Laboratory simulations of astrophysical jets and solar coronal loops: new results P. M. Bellan, D jets and in addition are intimately related to solar coronal loops. The jets are driven to solar coronal loops; the experimental layouts and images of typical plasmas are shown in Figs.1 and 2
Loops of Energy Bands for Bloch Waves in Optical Lattices By Matt Coles and Dmitry Pelinovsky
Pelinovsky, Dmitry
Loops of Energy Bands for Bloch Waves in Optical Lattices By Matt Coles and Dmitry Pelinovsky We in this context. These bifurcations generate loops in the energy bands of the Bloch waves near the ends is the possibility of loops in the energy bands associated with the nonlinear Bloch waves. This possibility was first
Hybrid Quantum Cosmology: Combining Loop and Fock Quantizations
Guillermo A. Mena Marugan; Mercedes Martin-Benito
2009-07-22
As a necessary step towards the extraction of realistic results from Loop Quantum Cosmology, we analyze the physical consequences of including inhomogeneities. We consider in detail the quantization of a gravitational model in vacuo which possesses local degrees of freedom, namely, the linearly polarized Gowdy cosmologies with the spatial topology of a three-torus. We carry out a hybrid quantization which combines loop and Fock techniques. We discuss the main aspects and results of this hybrid quantization, which include the resolution of the cosmological singularity, the polymeric quantization of the internal time, a rigorous definition of the quantum constraints and the construction of their solutions, the Hilbert structure of the physical states, and the recovery of a conventional Fock quantization for the inhomogeneities.
Magnetic and electric screening masses from Polyakov-loop correlations
Y. Maezawa; S. Aoki; S. Ejiri; T. Hatsuda; N. Ishii; K. Kanaya; N. Ukita; T. Umeda
2008-11-04
Screening properties of the quark gluon plasma are studied from Polyakov-loop correlation in lattice QCD simulations with two flavors of improved Wilson quarks at temperatures $T/\\Tpc \\simeq 1$--4 where $\\Tpc$ is the pseudocritical temperature. Using the Euclidean-time reflection symmetry and the charge conjugation symmetry, we introduce various types of Polyakov-loop correlation functions and extract screening masses in magnetic and electric sectors. We find that the temperature dependence of the screening masses are well described by the weak coupling expansion. We also find that a ratio of the screening masses in the electric sector to the magnetic sector shows qualitative agreement with a prediction from the dimensionally-reduced effective field theory and the N=4 supersymmetric Yang-Mills theory at $1.3 < T/\\Tpc < 3$.
Alternative quantization of the Hamiltonian in isotropic loop quantum cosmology
Jinsong Yang; You Ding; Yongge Ma
2009-04-28
Since there are quantization ambiguities in constructing the Hamiltonian constraint operator in isotropic loop quantum cosmology, it is crucial to check whether the key features of loop quantum cosmology, such as the quantum bounce and effective scenario, are robust against the ambiguities. In this paper, we consider a typical quantization ambiguity arising from the quantization of the field strength of the gravitational connection. An alternative Hamiltonian constraint operator is constructed, which is shown to have the correct classical limit by the semiclassical analysis. The effective Hamiltonian incorporating higher order quantum corrections is also obtained. In the spatially flat FRW model with a massless scalar field, the classical big bang is again replaced by a quantum bounce. Moreover, there are still great possibilities for the expanding universe to recollapse due to the quantum gravity effect. Thus, these key features are robust against this quantization ambiguity.
Higher curvature counter terms cause the bounce in loop cosmology
Helling, Robert C
2009-01-01
In the loop approach to the quantisation of gravity, one uses a Hilbert space which is too singular for some operators to be realised as derivatives. This is usually addressed by instead using finite difference operators at the Planck scale, a process known as ``polymerisation''. In the symmetry reduced example of loop cosmology, we study an ambiguity in the regularisation which we relate to the ambiguity of fixing the coefficients of infinitely many higher curvature counter terms augmenting the Einstein-Hilbert action. Thus the situation is comparable to he one in a naive perturbative treatment of quantum gravity with a cut-off where the necessary presence of infinitely many higher derivative terms compromises predictability. As a by-product, we demonstrate in an appendix that it is possible to have higher curvature actions for gravity which still lead to first order equations of motion like in the Friedmann case.
Higher curvature counter terms cause the bounce in loop cosmology
Robert C. Helling
2009-12-17
In the loop approach to the quantisation of gravity, one uses a Hilbert space which is too singular for some operators to be realised as derivatives. This is usually addressed by instead using finite difference operators at the Planck scale, a process known as ``polymerisation''. In the symmetry reduced example of loop cosmology, we study an ambiguity in the regularisation which we relate to the ambiguity of fixing the coefficients of infinitely many higher curvature counter terms augmenting the Einstein-Hilbert action. Thus the situation is comparable to he one in a naive perturbative treatment of quantum gravity with a cut-off where the necessary presence of infinitely many higher derivative terms compromises predictability. As a by-product, we demonstrate in an appendix that it is possible to have higher curvature actions for gravity which still lead to first order equations of motion like in the Friedmann case.
Evolution of reconnection along an arcade of magnetic loops
Paolo C. Grigis; Arnold O. Benz
2005-04-20
RHESSI observations of a solar flare showing continuous motions of double hard X-ray sources interpreted as footpoints of magnetic loops are presented. The temporal evolution shows many distinct emission peaks of duration of some tens of seconds ('elementary flare bursts'). Elementary flare bursts have been interpreted as instabilities or oscillations of the reconnection process leading to an unsteady release of magnetic energy. These interpretations based on two-dimensional concepts cannot explain these observations, showing that the flare elements are displaced in a third dimension along the arcade. Therefore, the observed flare elements are not a modulation of the reconnection process, but originate as this process progresses along an arcade of magnetic loops. Contrary to previous reports, we find no correlation between footpoint motion and hard X-ray flux. This flare apparently contradicts the predictions of the standard translation invariant 2.5D reconnection models.
Separable sequences in Bianchi I loop quantum cosmology
Cartin, Daniel; Khanna, Gaurav [Naval Academy Preparatory School, 197 Elliot Street, Newport, Rhode Island 02841 (United States); Physics Department, University of Massachusetts at Dartmouth, North Dartmouth, Massachusetts 02747 (United States)
2005-10-15
In this paper, we discuss the properties of one-parameter sequences that arise when solving the Hamiltonian constraint in Bianchi I loop quantum cosmology using a separation of variables method. In particular, we focus on finding an expression for the sequence for all real values of the parameter, and discuss the preclassicality of this function. We find that the behavior of these preclassical sequences imply time asymmetry on either side of the classical singularity in Bianchi I cosmology.
Independent Loop Invariants for 2+1 Gravity
R. Loll
1994-08-03
We identify an explicit set of complete and independent Wilson loop invariants for 2+1 gravity on a three-manifold $M=\\R\\times\\Sigma^g$, with $\\Sigma^g$ a compact oriented Riemann surface of arbitrary genus $g$. In the derivation we make use of a global cross section of the $PSU(1,1)$-principal bundle over Teichm\\"uller space given in terms of Fenchel-Nielsen coordinates.
Heliostat System with Wireless Closed-Loop Control
Broader source: Energy.gov [DOE]
This fact sheet summarizes a SunShot Initiative project led by Thermata to develop and demonstrate the first practical heliostat to use closed-loop tracking that can optically sense and control the reflected sunlight beam at the target. The expected benefits of this system include the reduction in the total installed cost of the heliostat field in a power tower concentrating solar power project.
Longitudinal magnetohydrodynamics oscillations in dissipative, cooling coronal loops
Al-Ghafri, K. S.; Ruderman, M. S.; Williamson, A.; Erdélyi, R., E-mail: app08ksa@sheffield.ac.uk, E-mail: m.s.ruderman@sheffield.ac.uk, E-mail: app09aw@sheffield.ac.uk, E-mail: robertus@sheffield.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
2014-05-01
This paper investigates the effect of cooling on standing slow magnetosonic waves in coronal magnetic loops. The damping mechanism taken into account is thermal conduction that is a viable candidate for dissipation of slow magnetosonic waves in coronal loops. In contrast to earlier studies, here we assume that the characteristic damping time due to thermal conduction is not small, but arbitrary, and can be of the order of the oscillation period, i.e., a temporally varying plasma is considered. The approximation of low-beta plasma enables us to neglect the magnetic field perturbation when studying longitudinal waves and consider, instead, a one-dimensional motion that allows a reliable first insight into the problem. The background plasma temperature is assumed to be decaying exponentially with time, with the characteristic cooling timescale much larger than the oscillation period. This assumption enables us to use the WKB method to study the evolution of the oscillation amplitude analytically. Using this method we obtain the equation governing the oscillation amplitude. The analytical expressions determining the wave properties are evaluated numerically to investigate the evolution of the oscillation frequency and amplitude with time. The results show that the oscillation period increases with time due to the effect of plasma cooling. The plasma cooling also amplifies the amplitude of oscillations in relatively cool coronal loops, whereas, for very hot coronal loop oscillations the damping rate is enhanced by the cooling. We find that the critical point for which the amplification becomes dominant over the damping is in the region of 4 MK. These theoretical results may serve as impetus for developing the tools of solar magneto-seismology in dynamic plasmas.
Closed-loop air cooling system for a turbine engine
North, William Edward (Winter Springs, FL)
2000-01-01
Method and apparatus are disclosed for providing a closed-loop air cooling system for a turbine engine. The method and apparatus provide for bleeding pressurized air from a gas turbine engine compressor for use in cooling the turbine components. The compressed air is cascaded through the various stages of the turbine. At each stage a portion of the compressed air is returned to the compressor where useful work is recovered.
NOT-SO-GOOD LOOP-DISPLAY SCHEME IN FLOWCHART
Kundu, Sukhamay
entry point. ·? What happens if box "1" is itself a do-while loop? How about the case if it is a while on the same horizontal line, we can associate with each subtree a box with an entry-point and these boxes-Node and Branch-node: width, height, leftTopDisplacement (LTD), and leftBottomDisplacement (LBD) unique entry
Strong cooperativity and inhibitory effects in DNA multi-looping processes
Artur Garcia-Saez; J. Miguel Rubi
2009-03-23
We show the existence of a high interrelation between the different loops that may appear in a DNA segment. Conformational changes in a chain segment caused by the formation of a particular loop may either promote or prevent the appearance of another. The underlying loop selection mechanism is analyzed by means of a Hamiltonian model from which the looping free energy and the corresponding repression level can be computed. We show significant differences between the probability of single and multiple loop formation. The consequences that these collective effects might have on gene regulation processes are outlined.
A solar active region loop compared with a 2D MHD model
Gontikakis, C; Dara, H C; Tsinganos, K
2005-01-01
We analyzed a coronal loop observed with the Normal Incidence Spectrometer (NIS), which is part of the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO). The measured Doppler shifts and proper motions along the selected loop strongly indicate unidirectional flows. Analysing the Emission Measure Curves of the observed spectral lines, we estimated that the temperature along the loop was about 380000 K. We adapted a solution of the ideal MHD steady equations to our set of measurements. The derived energy balance along the loop, as well as the advantages/disadvantages of this MHD model for understanding the characteristics of solar coronal loops are discussed.
A solar active region loop compared with a 2D MHD model
C. Gontikakis; G. J. D. Petrie; H. C. Dara; K. Tsinganos
2005-03-31
We analyzed a coronal loop observed with the Normal Incidence Spectrometer (NIS), which is part of the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO). The measured Doppler shifts and proper motions along the selected loop strongly indicate unidirectional flows. Analysing the Emission Measure Curves of the observed spectral lines, we estimated that the temperature along the loop was about 380000 K. We adapted a solution of the ideal MHD steady equations to our set of measurements. The derived energy balance along the loop, as well as the advantages/disadvantages of this MHD model for understanding the characteristics of solar coronal loops are discussed.
Onset of electron acceleration in a flare loop
Sharykin, Ivan; Liu, Siming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210008 (China); Fletcher, Lyndsay, E-mail: liusm@pmo.ac.cn [School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
2014-09-20
We carried out a detailed analysis of X-ray and radio observations of a simple flare loop that occurred on 2002 August 12, with the impulsive hard X-ray (HXR) light curves dominated by a single pulse. The emission spectra of the early impulsive phase are consistent with an isothermal model in the coronal loop with a temperature reaching several keV. A power-law high-energy spectral tail is evident near the HXR peak time, in accordance with the appearance of footpoints at high energies, and is well correlated with the radio emission. The energy content of the thermal component keeps increasing gradually after the disappearance of this nonthermal component. These results suggest that electron acceleration only covers the central period of a longer and more gradual energy dissipation process and that the electron transport within the loop plays a crucial role in the formation of the inferred power-law electron distribution. The spectral index of power-law photons shows a very gradual evolution, indicating that the electron accelerator is in a quasi-steady state, which is confirmed by radio observations. These results are consistent with the theory of stochastic electron acceleration from a thermal background. Advanced modeling with coupled electron acceleration and spatial transport processes is needed to explain these observations more quantitatively, which may reveal the dependence of the electron acceleration on the spatial structure of the acceleration region.
Lattice refining loop quantum cosmology, anisotropic models, and stability
Bojowald, Martin; Cartin, Daniel; Khanna, Gaurav [Institute for Gravitation and the Cosmos, Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania 16802 (United States); Naval Academy Preparatory School, 197 Elliot Street, Newport, Rhode Island 02841 (United States); Physics Department, University of Massachusetts at Dartmouth, North Dartmouth, Massachusetts 02747 (United States)
2007-09-15
A general class of loop quantizations for anisotropic models is introduced and discussed, which enhances loop quantum cosmology by relevant features seen in inhomogeneous situations. The main new effect is an underlying lattice which is being refined during dynamical changes of the volume. In general, this leads to a new feature of dynamical difference equations which may not have constant step-size, posing new mathematical problems. It is discussed how such models can be evaluated and what lattice refinements imply for semiclassical behavior. Two detailed examples illustrate that stability conditions can put strong constraints on suitable refinement models, even in the absence of a fundamental Hamiltonian which defines changes of the underlying lattice. Thus, a large class of consistency tests of loop quantum gravity becomes available. In this context, it will also be seen that quantum corrections due to inverse powers of metric components in a constraint are much larger than they appeared recently in more special treatments of isotropic, free scalar models where they were artificially suppressed.
Simulations of Solar Jets Confined by Coronal Loops
Wyper, P F
2015-01-01
Coronal jets are collimated, dynamic events that occur over a broad range of spatial scales in the solar corona. In the open magnetic field of coronal holes, jets form quasi-radial spires that can extend far out into the heliosphere, while in closed-field regions the jet outflows are confined to the corona. We explore the application of the embedded-bipole model to jets occurring in closed coronal loops. In this model, magnetic free energy is injected slowly by footpoint motions that introduce twist within the closed dome of the jet source region, and is released rapidly by the onset of an ideal kink-like instability. Two length scales characterize the system: the width (N) of the jet source region and the footpoint separation (L) of the coronal loop that envelops the jet source. We find that the jet characteristics are highly sensitive to the ratio L/N, in both the conditions for initiation and the subsequent dynamics. The longest-lasting and most energetic jets occur along long coronal loops with large L/N ...
Master integrals for the four-loop Sudakov form factor
Boels, Rutger; Yang, Gang
2015-01-01
The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally ($\\mathcal{N}=4$) supersymmetric Yang-Mills theory (SYM) in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. Probably the simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was obtained in integrand form in a previous work for $\\mathcal{N}=4$ SYM, up to a single parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP) identities using (a tweaked version of) Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. The appearing master integrals are cross-checked using algebraic techniques explored in the Mint package. The ...
Recipes and Ingredients for Neutrino Mass at Loop Level
Yasaman Farzan; Silvia Pascoli; Michael A. Schmidt
2013-03-25
The large hierarchy between the neutrino mass scale and that of the other fermions seems to be unnatural from a theoretical point of view. Various strategies have been devised in order to generate naturally small values of neutrino masses. One of these techniques is neutrino mass generation at the loop level which requires a mechanism, e.g., a symmetry, to forbid the lower order contributions. Here, we study in detail the conditions on this type of symmetries. We put special emphasis on the discrete Z_n symmetries as a simple example but our results can be also extended to more general groups. We find that regardless of the details of the symmetry, in certain cases the existence of a lower order contribution to neutrino masses can be determined by the topology of the diagrams with a given number of loops. We discuss the lepton flavor violating rare decays as well as (g-2)_\\mu in this class of models, which generically appear at the one loop level. Typically the imposed symmetry has important implications for dark matter, with the possibility of stabilizing one or even multiple dark matter candidates.
Soft X-ray emission in flaring coronal loops
Pinto, R F; Brun, A S
2014-01-01
Solar flares are associated with intense soft X-ray emission generated by the hot flaring plasma in coronal magnetic loops. Kink unstable twisted flux-ropes provide a source of magnetic energy which can be released impulsively and account for the heating of the plasma in flares. We investigate the temporal, spectral and spatial evolution of the properties of the thermal X-ray emission produced in such kink-unstable magnetic flux-ropes using a series of MHD simulations. We deduce emission diagnostics and their temporal evolution and discuss the results of the simulations with respect to observations. The numerical setup used consists of a highly twisted loop embedded in a region of uniform and untwisted background coronal magnetic field. We let the kink instability develop, compute the evolution of the plasma properties in the loop (density, temperature) and deduce the X-ray emission properties of the plasma during the whole flaring episode. During the initial phase of the instability plasma heating is mostly ...
Chandra Observations of the Northeastern Rim of the Cygnus Loop
Satoru Katsuda; Hiroshi Tsunemi; Masashi Kimura; Koji Mori
2008-06-25
We present results from spatially resolved spectral analyses of the northeastern (NE) rim of the Cygnus Loop supernova remnant (SNR) based on two Chandra observations. One pointing includes northern outermost abundance-enhanced regions discovered by recent Suzaku observations, while the other pointing is located on regions with "normal" abundances in the NE rim of the Cygnus Loop. The superior spatial resolving power of Chandra allows us to reveal that the abundance-enhanced region is concentrated in an about 200"-thickness region behind the shock front. We confirm absolute metal abundances (i.e., relative to H) as well as abundance ratios between metals are consistent with those of the solar values within a factor of about 2. Also, we find that the emission measure in the region gradually decreases toward the shock front. These features are in contrast with those of the ejecta fragments around the Vela SNR, which leads us to believe that the abundance enhancements are not likely due to metal-rich ejecta. We suggest that the origin of the plasma in this region is the interstellar medium (ISM). In the "normal" abundance regions, we confirm that abundances are depleted to the solar values by a factor of about 5 that is not expected in the ISM around the Cygnus Loop. Introduction of non-thermal emission in our model fitting can not naturally resolve the abundance-depletion problem. The origin of the depletion still remains as an open question.
The matter bounce scenario in loop quantum cosmology
Wilson-Ewing, Edward, E-mail: wilson-ewing@cpt.univ-mrs.fr [Aix-Marseille Université, CNRS UMR 7332, CPT, 13288 Marseille (France)
2013-03-01
In the matter bounce scenario, a dust-dominated contracting space-time generates scale-invariant perturbations that, assuming a nonsingular bouncing cosmology, propagate to the expanding branch and set appropriate initial conditions for the radiation-dominated era. Since this scenario depends on the presence of a bounce, it seems appropriate to consider it in the context of loop quantum cosmology where a bouncing universe naturally arises. For a pressureless collapsing universe in loop quantum cosmology, the predicted power spectrum of the scalar perturbations after the bounce is scale-invariant and the tensor to scalar ratio is negligibly small. A slight red tilt can be given to the scale-invariance of the scalar perturbations by a scalar field whose equation of state is P = ???, where ? is a small positive number. Then, the power spectrum for tensor perturbations is also almost scale-invariant with the same red tilt as the scalar perturbations, and the tensor to scalar ratio is expected to be r ? 9 × 10{sup ?4}. Finally, for the predicted amplitude of the scalar perturbations to agree with observations, the critical density in loop quantum cosmology must be of the order ?{sub c} ? 10{sup ?9}?{sub Pl}.
Observational evidence for return currents in solar flare loops
Marina Battaglia; Arnold O. Benz
2008-06-11
Context: The common flare scenario comprises an acceleration site in the corona and particle transport to the chromosphere. Using satellites available to date it has become possible to distinguish between the two processes of acceleration and transport, and study the particle propagation in flare loops in detail, as well as complete comparisons with theoretical predictions. Aims: We complete a quantitative comparison between flare hard X-ray spectra observed by RHESSI and theoretical predictions. This enables acceleration to be distinguished from transport and the nature of transport effects to be explored. Methods: Data acquired by the RHESSI satellite were analyzed using full sun spectroscopy as well as imaging spectroscopy methods. Coronal source and footpoint spectra of well observed limb events were analyzed and quantitatively compared to theoretical predictions. New concepts are introduced to existing models to resolve discrepancies between observations and predictions. Results: The standard thin-thick target solar flare model cannot explain the observations of all events. In the events presented here, propagation effects in the form of non-collisional energy loss are of importance to explain the observations. We demonstrate that those energy losses can be interpreted in terms of an electric field in the flare loop. One event seems consistent with particle propagation or acceleration in lower than average density in the coronal source. Conclusions: We find observational evidence for an electric field in flare loops caused by return currents.
A unified view of coronal loop contraction and oscillation in flares
Russell, Alexander J B; Fletcher, Lyndsay
2015-01-01
Context: Transverse loop oscillations and loop contractions are commonly associated with solar flares, but the two types of motion have traditionally been regarded as separate phenomena. Aims: We present an observation of coronal loops contracting and oscillating following onset of a flare. We aim to explain why both behaviours are seen together and why only some of the loops oscillate. Methods: A time sequence of SDO/AIA 171 \\r{A} images is analysed to identify positions of coronal loops following the onset of M6.4 flare SOL2012-03-09T03:53. We focus on five loops in particular, all of which contract during the flare, with three of them oscillating as well. A simple model is then developed for contraction and oscillation of a coronal loop. Results: We propose that coronal loop contractions and oscillations can occur in a single response to removal of magnetic energy from the corona. Our model reproduces the various types of loop motion observed and explains why the highest loops oscillate during their contra...
How current loops and solenoids curve space-time
A. Füzfa
2015-04-01
The curved space-time around current loops and solenoids carrying arbitrarily large steady electric currents is obtained from the numerical resolution of the coupled Einstein-Maxwell equations in cylindrical symmetry. The artificial gravitational field associated to the generation of a magnetic field produces gravitational redshift of photons and gravitational acceleration of neutral massive particles. The strength of the generated gravitational field is extremely weak from what can be obtained through present technology, although it might be detectable with high-precision measurements such as atom interferometry.
"Closed-loop" analysis of a thermo-charged capacitor
Germano D'Abramo
2015-05-04
In this Letter, an explicit application of conservation of energy and zero net work principle around a closed path ("closed-loop" analysis) is carried out on a thermo-charged capacitor at equilibrium with ambient heat at uniform temperature. This analysis corroborates the results of previous studies [Phys.Lett.A 374 (2010) 1801, Physica A 390 (2011) 481] that a potential drop $\\Delta V$ does actually occur at capacitor terminals. Finally, a conventional photoelectric emission experiment is proposed to indirectly text thermo-charged capacitor functioning.
Sinc function representation and three-loop master diagrams
Easther, Richard; Guralnik, Gerald; Hahn, Stephen
2001-04-15
We test the Sinc function representation, a novel method for numerically evaluating Feynman diagrams, by using it to evaluate the three-loop master diagrams. Analytical results have been obtained for all these diagrams, and we find excellent agreement between our calculations and the exact values. The Sinc function representation converges rapidly, and it is straightforward to obtain accuracies of 1 part in 10{sup 6} for these diagrams and with longer runs we found results better than 1 part in 10{sup 12}. Finally, this paper extends the Sinc function representation to diagrams containing massless propagators.
FINGERPRINTS OF GALACTIC LOOP I ON THE COSMIC MICROWAVE BACKGROUND
Liu, Hao [Niels Bohr Institute and Discovery Center, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen Ø (Denmark); Mertsch, Philipp [Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States); Sarkar, Subir, E-mail: liuhao@nbi.dk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)
2014-07-10
We investigate possible imprints of galactic foreground structures such as the ''radio loops'' in the derived maps of the cosmic microwave background. Surprisingly, there is evidence for these not only at radio frequencies through their synchrotron radiation, but also at microwave frequencies where emission by dust dominates. This suggests the mechanism is magnetic dipole radiation from dust grains enriched by metallic iron or ferrimagnetic molecules. This new foreground we have identified is present at high galactic latitudes, and potentially dominates over the expected B-mode polarization signal due to primordial gravitational waves from inflation.
Closed loop air cooling system for combustion turbines
Huber, David John (North Canton, OH); Briesch, Michael Scot (Orlando, FL)
1998-01-01
Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.
Hybrid Quantum Gowdy Cosmology: Combining Loop and Fock Quantizations
Mercedes Martin-Benito; Luis J. Garay; Guillermo A. Mena Marugan
2008-08-27
We quantize an inhomogeneous cosmological model using techniques that include polymeric quantization. More explicitly, we construct well defined operators to represent the constraints and find the physical Hilbert space formed by their solutions, which reproduces the conventional Fock quantization for the inhomogeneities. The initial singularity is resolved in this inhomogeneous model in an extremely simple way and without imposing special boundary conditions, thus ensuring the robustness and generality of this resolution. Furthermore this quantization constitutes a well founded step towards the extraction of physical results and consequences from loop quantum cosmology, given the central role of the inhomogeneities in modern cosmology.
Loop Quantum Theory Applied to Biology and Nonlinear Whole Biology
Yi-Fang Chang
2008-01-02
The loop quantum theory, which constitutes a very small discontinuous space, as new method is applied to biology. The model of protein folding and lungs is proposed. In the model, some known results are used, and four approximate conclusions are obtained: their structures are quantized, their space regions are finite, various singularities correspond to folding and crossed points, and different types of catastrophe exist. Further, based on the inseparability and correlativity of the biological systems, the nonlinear whole biology is proposed, and four basic hypotheses are formed. It may unify reductionism and holism, structuralism and functionalism. Finally, the medical meaning of the theory is discussed briefly.
Witten's loop in the flipped SU(5) unification
Malinský, Michal; Kolešová, Helena
2013-01-01
We study a very simple, yet potentially realistic renormalizable flipped SU(5) scenario in which the right-handed neutrino masses are generated at very high energies by means of a two-loop diagram similar to that identified by E. Witten in the early 1980's in the SO(10) GUT framework. This mechanism leaves its traces in the baryon number violating signals such as the proton decay, especially in the "clean" channels with a charged lepton and a neutral meson in the final state.
Witten's loop in the flipped SU(5) unification
Michal Malinský; Carolina Arbeláez Rodríguez; Helena Kolešová
2013-10-03
We study a very simple, yet potentially realistic renormalizable flipped SU(5) scenario in which the right-handed neutrino masses are generated at very high energies by means of a two-loop diagram similar to that identified by E. Witten in the early 1980's in the SO(10) GUT framework. This mechanism leaves its traces in the baryon number violating signals such as the proton decay, especially in the "clean" channels with a charged lepton and a neutral meson in the final state.
Emergence of General Relativity from Loop Quantum Gravity: A Summary
Chun-Yen Lin
2011-12-27
A model is proposed to demonstrate that classical general relativity can emerge from loop quantum gravity, in a relational description of gravitational field in terms of the coordinates given by matter. Local Dirac observables and coherent states are defined to explore physical content of the model. Expectation values of commutators between the observables for the coherent states recover the four-dimensional diffeomorphism algebra and the large-scale dynamics of the gravitational field relative to the matter coordinates. Both results conform with general relativity up to calculable corrections near singularities.
System having unmodulated flux locked loop for measuring magnetic fields
Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Blue Springs, MO)
2006-08-15
A system (10) for measuring magnetic fields, wherein the system (10) comprises an unmodulated or direct-feedback flux locked loop (12) connected by first and second unbalanced RF coaxial transmission lines (16a, 16b) to a superconducting quantum interference device (14). The FLL (12) operates for the most part in a room-temperature or non-cryogenic environment, while the SQUID (14) operates in a cryogenic environment, with the first and second lines (16a, 16b) extending between these two operating environments.
Loop quantization of the Gowdy model with local rotational symmetry
de Blas, Daniel Martín; Paw?owski, Tomasz
2015-01-01
We provide a full quantization of the vacuum Gowdy model with local rotational symmetry. We consider a redefinition of the constraints where the Hamiltonian Poisson-commutes with itself. We then apply of the canonical quantization program of loop quantum gravity within an improved dynamics scheme. We identify the exact solutions of the constraints and the physical observables, and we construct the physical Hilbert space. It is remarkable that quantum spacetimes are free of singularities. New quantum observables naturally arising in the treatment partially codify the discretization of the geometry. The preliminary analysis of the asymptotic future/past of the evolution indicates that the existing Abelianization technique needs further refinement.
Dirac Fields in Loop Quantum Gravity and Big Bang Nucleosynthesis
Martin Bojowald; Rupam Das; Robert J. Scherrer
2008-03-19
Big Bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of Big Bang nucleosynthesis, to place bounds on these corrections.
Loop quantum cosmology, non-Gaussianity, and CMB power asymmetry
Ivan Agullo
2015-07-16
We argue that the anomalous power asymmetry observed in the cosmic microwave background (CMB) may have originated in a cosmic bounce preceding inflation. In loop quantum cosmology (LQC) the big bang singularity is generically replaced by a bounce due to quantum gravitational effects. We compute the spectrum of inflationary non-Gaussianity and show that strong correlation between observable scales and modes with longer (super-horizon) wavelength arise as a consequence of the evolution of perturbations across the LQC bounce. These correlations are strongly scale dependent and induce a dipole-dominated modulation on large angular scales in the CMB, in agreement with observations.
Loop quantum cosmology, non-Gaussianity, and CMB power asymmetry
Agullo, Ivan
2015-01-01
We argue that the anomalous power asymmetry observed in the cosmic microwave background (CMB) may have originated in a cosmic bounce preceding inflation. In loop quantum cosmology (LQC) the big bang singularity is generically replaced by a bounce due to quantum gravitational effects. We compute the spectrum of inflationary non-Gaussianity and show that strong correlation between observable scales and modes with longer (super-horizon) wavelength arise as a consequence of the evolution of perturbations across the LQC bounce. These correlations are strongly scale dependent and induce a dipole-dominated modulation on large angular scales in the CMB, in agreement with observations.
Supersymmetric Wilson Loops in N=4 Super Chern-Simons-matter Theory
Ouyang, Hao; Zhang, Jia-ju
2015-01-01
We investigate the supersymmetric Wilson loops in d=3 N=4 super Chern-Simons-matter theory obtained from non-chiral orbifold of ABJM theory. We work in both the Minkowski spacetime and Euclidean space, and we construct the 1/4 and 1/2 BPS Wilson loops. We also give a complete proof that the difference between 1/4 and 1/2 Wilson loops are Q-exact with Q being some supercharge preserved by both the 1/4 and 1/2 Wilson loops. This is important in applying the localization techniques to compute the vacuum expectation values of Wilson loops. We also study the M-theory dual of the 1/2 BPS circular Wilson loop.
Supersymmetric Wilson loops in N=4 super Chern-Simons-matter theory
Hao Ouyang; Jun-Bao Wu; Jia-ju Zhang
2015-12-03
We investigate the supersymmetric Wilson loops in $d=3$ $\\mathcal{N}=4$ super Chern-Simons-matter theory obtained from non-chiral orbifold of ABJM theory. We work in both Minkowski spacetime and Euclidean space, and we construct 1/4 and 1/2 BPS Wilson loops. We also provide a complete proof that the difference between 1/4 and 1/2 Wilson loops is $Q$-exact with $Q$ being some supercharge that is preserved by both the 1/4 and 1/2 Wilson loops. This plays an important role in applying the localization techniques to compute the vacuum expectation values of Wilson loops. We also study the M-theory dual of the 1/2 BPS circular Wilson loop.
Rugh, J. P.
2013-07-01
Plug-in hybrid electric vehicles and electric vehicles have increased vehicle thermal management complexity, using separate coolant loop for advanced power electronics and electric motors. Additional thermal components result in higher costs. Multiple cooling loops lead to reduced range due to increased weight. Energy is required to meet thermal requirements. This presentation for the 2013 Annual Merit Review discusses integrated vehicle thermal management by combining fluid loops in electric drive vehicles.
Two-loop enhancement factor for 1/Q corrections to event shapes in deep inelastic scattering
Mrinal Dasgupta; Bryan R. Webber
2000-10-22
We compute the two-loop enhancement factors for our earlier one-loop calculations of leading (1/Q) power corrections to the mean values of some event shape variables in deep inelastic lepton scattering. The enhancement is found to be equal to the universal ``Milan factor'' for those shape variables considered, provided the one-loop calculation is performed in a particular way. As a result, the phenomenology of power corrections to DIS event shapes remains largely unaffected.
Secular effects on inflation from one-loop quantum gravity
J. A. Cabrer; D. Espriu
2007-10-03
In this paper we revisit and extend a previous analysis where the possible relevance of quantum gravity effects in a cosmological setup was studied. The object of interest are non-local (logarithmic) terms generated in the effective action of gravity due to the exchange in loops of massless modes (such as photons or the gravitons themselves). We correct one mistake existing in the previous work and discuss the issue in a more general setting in different cosmological scenarios. We obtain the one-loop quantum-corrected evolution equations for the cosmological scale factor up to a given order in a derivative expansion in two particular cases: a matter dominated universe with vanishing cosmological constant, and in a de Sitter universe. We show that the quantum corrections, albeit tiny, may have a secular effect that eventually modifies the expansion rate. For a de Sitter universe they tend to slow down the rate of the expansion, while the effect seems to have the opposite sign in a matter dominated universe. To partly understand these effects we provide a complementary newtonian analysis.
Environmental Impact on the Southeast Limb of the Cygnus Loop
N. A. Levenson; James R. Graham
2004-12-17
We analyze observations from the Chandra X-ray Observatory of the southeast knot of the Cygnus Loop supernova remnant. In this region, the blast wave propagates through an inhomogeneous environment. Extrinsic differences and subsequent multiple projections along the line of sight rather than intrinsic shock variations, such as fluid instabilities, account for the apparent complexity of the images. Interactions between the supernova blast wave and density enhancements of a large interstellar cloud can produce the morphological and spectral characteristics. Most of the X-ray flux arises in such interactions, not in the diffuse interior of the supernova remnant. Additional observations at optical and radio wavelengths support this account of the existing interstellar medium and its role in shaping the Cygnus Loop, and they demonstrate that the southeast knot is not a small cloud that the blast wave has engulfed. These data are consistent with rapid equilibration of electron and ion temperatures behind the shock front, and the current blast wave velocity v_{bw} approx 330 km/s. Most of this area does not show strong evidence for non-equilibrium ionization conditions, which may be a consequence of the high densities of the bright emission regions.
Black hole spectroscopy from Loop Quantum Gravity models
Aurelien Barrau; Xiangyu Cao; Karim Noui; Alejandro Perez
2015-04-21
Using Monte Carlo simulations, we compute the integrated emission spectra of black holes in the framework of Loop Quantum Gravity (LQG). The black hole emission rates are governed by the entropy whose value, in recent holographic loop quantum gravity models, was shown to agree at leading order with the Bekenstein-Hawking entropy. Quantum corrections depend on the Barbero-Immirzi parameter $\\gamma$. Starting with black holes of initial horizon area $A \\sim 10^2$ in Planck units, we present the spectra for different values of $\\gamma$. Each spectrum clearly decomposes in two distinct parts: a continuous background which corresponds to the semi-classical stages of the evaporation and a series of discrete peaks which constitutes a signature of the deep quantum structure of the black hole. We show that $\\gamma$ has an effect on both parts that we analyze in details. Finally, we estimate the number of black holes and the instrumental resolution required to experimentally distinguish between the considered models.
Testing Loop Quantum Gravity and Electromagnetic Dark Energy in Superconductors
Clovis Jacinto de Matos
2009-08-06
In 1989 Cabrera and Tate reported an anomalous excess of mass of the Cooper pairs in rotating thin Niobium rings. So far, this experimental result never received a proper theoretical explanation in the context of superconductor's physics. In the present work we argue that what Cabrera and Tate interpreted as an anomalous excess of mass can also be associated with a deviation from the classical gravitomagnetic Larmor theorem due to the presence of dark energy in the superconductor, as well as with the discrete structure of the area of the superconducting Niobium ring as predicted by Loop Quantum Gravity. From Cabrera and Tate measurements we deduce that the quantization of spacetime in superconducting circular rings occurs at the Planck-Einstein scale $l_{PE} = (\\hbar G/c^3 \\Lambda)^{1/4}\\sim 3.77\\times 10 ^{-5} m$, instead of the Planck scale $l_{P} =(\\hbar G / c^3)^{1/2}=1.61 \\times 10 ^{-35} m$, with an Immirzi parameter which depends on the specific critical temperature of the superconducting material and on the area of the ring. The stephan-Boltzmann law for quantized areas delimited by superconducting rings is predicted, and an experimental concept based on the electromagnetic black-body radiation emitted by this surfaces, is proposed to test loop quantum gravity and electromagnetic dark energy in superconductors.
Chandra Observations of the Northeastern Rim of the Cygnus Loop
Katsuda, Satoru; Kimura, Masashi; Mori, Koji
2008-01-01
We present results from spatially resolved spectral analyses of the northeastern (NE) rim of the Cygnus Loop supernova remnant (SNR) based on two Chandra observations. One pointing includes northern outermost abundance-enhanced regions discovered by recent Suzaku observations, while the other pointing is located on regions with "normal" abundances in the NE rim of the Cygnus Loop. The superior spatial resolving power of Chandra allows us to reveal that the abundance-enhanced region is concentrated in an about 200"-thickness region behind the shock front. We confirm absolute metal abundances (i.e., relative to H) as well as abundance ratios between metals are consistent with those of the solar values within a factor of about 2. Also, we find that the emission measure in the region gradually decreases toward the shock front. These features are in contrast with those of the ejecta fragments around the Vela SNR, which leads us to believe that the abundance enhancements are not likely due to metal-rich ejecta. We ...
12 loops and triple wrapping in ABJM theory from integrability
Anselmetti, Lorenzo; Cavaglià, Andrea; Tateo, Roberto
2015-01-01
Adapting a method recently proposed by C. Marboe and D. Volin for ${\\cal N}$=4 super-Yang-Mills, we develop an algorithm for a systematic weak coupling expansion for anomalous dimensions of operators in the $sl(2)$-like sector of planar $\\mathcal{N}$=6 super-Chern-Simons. The method relies on the Quantum Spectral Curve formulation of the problem and the expansion is written in terms of the interpolating function $h(\\lambda)$, with coefficients expressible as combinations of Euler-Zagier sums with alternating signs. We present explicit results up to 12 loops (six nontrivial orders) for various twist L=1 and L=2 operators, corresponding to triple and double wrapping terms, respectively, which are beyond the reach of the Asymptotic Bethe Ansatz as well as L\\"uscher's corrections. The algorithm works for generic values of L and S and in principle can be used to compute arbitrary orders of the weak coupling expansion. For the simplest operator with L=1 and spin S=1, the 12-loop computation matches very well with t...
The four-loop six-gluon NMHV ratio function
Dixon, Lance J; McLeod, Andrew J
2015-01-01
We use the hexagon function bootstrap to compute the ratio function which characterizes the next-to-maximally-helicity-violating (NMHV) six-point amplitude in planar $\\mathcal{N} = 4$ super-Yang-Mills theory at four loops. A powerful constraint comes from dual superconformal invariance, in the form of a $\\bar{Q}$ differential equation, which heavily constrains the first derivatives of the transcendental functions entering the ratio function. At four loops, it leaves only a 34-parameter space of functions. Constraints from the collinear limits, and from the multi-Regge limit at the leading-logarithmic (LL) and next-to-leading-logarithmic (NLL) order, suffice to fix these parameters and obtain a unique result. We test the result against multi-Regge predictions at NNLL and N$^3$LL, and against predictions from the operator product expansion involving one and two flux-tube excitations; all cross-checks are satisfied. We study the analytical and numerical behavior of the parity-even and parity-odd parts on various...
Loop quantum gravity, twistors, and some perspectives on the problem of time
Simone Speziale
2014-04-16
I give a brief introduction to the relation between loop quantum gravity and twistor theory, and comment on some perspectives on the problem of time.
Two-point functions for SU(3) Polyakov Loops near T_c
Adrian Dumitru; Robert D. Pisarski
2002-04-23
We discuss the behavior of two point functions for Polyakov loops in a SU(3) gauge theory about the critical temperature, T_c. From a Z(3) model, in mean field theory we obtain a prediction for the ratio of masses at T_c, extracted from correlation functions for the imaginary and real parts of the Polyakov loop. This ratio is m_i/m_r = 3 if the potential only includes terms up to quartic order in the Polyakov loop; its value changes as pentic and hexatic interactions become important. The Polyakov Loop Model then predicts how m_i/m_r changes above T_c.
Thomas L. Shaw, President LOOP LLC Before Public Meeting on the...
Broader source: Energy.gov (indexed) [DOE]
the Gulf Coast, primarily Corpus Christi, Texas. LOOP also receives crude oil through pipelines from the Mars and Thunder Horse offshore production platforms. These production...
Statistical evidence for the existence of Alfvénic turbulence in solar coronal loops
Liu, Jiajia [Earth and Space Science School, University of Science and Technology of China, No. 96, JinZhai Road, Hefei (China); McIntosh, Scott W.; Bethge, Christian [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); De Moortel, Ineke; Threlfall, James, E-mail: ljj128@mail.ustc.edu.cn [School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom)
2014-12-10
Recent observations have demonstrated that waves capable of carrying large amounts of energy are ubiquitous throughout the solar corona. However, the question of how this wave energy is dissipated (on which timescales and length scales) and released into the plasma remains largely unanswered. Both analytic and numerical models have previously shown that Alfvénic turbulence may play a key role not only in the generation of the fast solar wind, but in the heating of coronal loops. In an effort to bridge the gap between theory and observations, we expand on a recent study by analyzing 37 clearly isolated coronal loops using data from the Coronal Multi-channel Polarimeter instrument. We observe Alfvénic perturbations with phase speeds which range from 250 to 750 km s{sup –1} and periods from 140 to 270 s for the chosen loops. While excesses of high-frequency wave power are observed near the apex of some loops (tentatively supporting the onset of Alfvénic turbulence), we show that this excess depends on loop length and the wavelength of the observed oscillations. In deriving a proportional relationship between the loop length/wavelength ratio and the enhanced wave power at the loop apex, and from the analysis of the line widths associated with these loops, our findings are supportive of the existence of Alfvénic turbulence in coronal loops.
Canonical Transformations and Loop Formulation of SU(N) Lattice Gauge Theories
Manu Mathur; T. P. Sreeraj
2015-09-14
We construct canonical transformations to reformulate SU(N) Kogut-Susskind lattice gauge theory in terms of a set of fundamental loop & string flux operators along with their canonically conjugate loop & string electric fields. We show that as a consequence of SU(N) Gauss laws all SU(N) string degrees of freedom become cyclic and decouple from the physical Hilbert space ${\\cal H}^p$. The canonical relations between the initial SU(N) link operators and the final SU(N) loop & string operators over the entire lattice are worked out in a self consistent manner. The Kogut-Susskind Hamiltonian rewritten in terms of the fundamental physical loop operators has global SU(N) invariance. There are no gauge fields. We further show that the $(1/g^2)$ magnetic field terms on plaquettes create and annihilate the fundamental plaquette loop fluxes while the $(g^2)$ electric field terms describe all their interactions. In the weak coupling ($g^2 \\rightarrow 0$) continuum limit the SU(N) loop dynamics is described by SU(N) spin Hamiltonian with nearest neighbour interactions. In the simplest SU(2) case, where the canonical transformations map the SU(2) loop Hilbert space into the Hilbert spaces of hydrogen atoms, we analyze the special role of the hydrogen atom dynamical symmetry group $SO(4,2)$ in the loop dynamics and the spectrum. A simple tensor network ansatz in the SU(2) gauge invariant hydrogen atom loop basis is discussed.
PLASMOID EJECTIONS AND LOOP CONTRACTIONS IN AN ERUPTIVE M7.7...
Office of Scientific and Technical Information (OSTI)
PLASMOID EJECTIONS AND LOOP CONTRACTIONS IN AN ERUPTIVE M7.7 SOLAR FLARE: EVIDENCE OF PARTICLE ACCELERATION AND HEATING IN MAGNETIC RECONNECTION OUTFLOWS Citation Details...
ORC Closed Loop Control Systems for Transient and Steady State Duty Cycles
Broader source: Energy.gov [DOE]
System-level models using iterative concept analysis are being used on a closed loop controlled, waste heat recovery system running automatically over various drive cycles.
Geek-Up[08.27.10] -- Geothermal Stores, Graphene Loops, Nozzle...
Broader source: Energy.gov (indexed) [DOE]
at Oak Ridge National Laboratory (ORNL) have discovered how loops develop in graphene - an electrically conductive high-strength low-weight material (think of it as an...
Superbounce and Loop Quantum Cosmology Ekpyrosis from Modified Gravity
V. K. Oikonomou
2015-04-07
As is known, in modified cosmological theories of gravity many of the cosmologies which could not be generated by standard Einstein gravity, can be consistently described by $F(R)$ theories. Using known reconstruction techniques, we investigate which $F(R)$ theories can lead to a Hubble parameter describing two types of cosmological bounces, the superbounce model, related to supergravity and non-supersymmetric models of contracting ekpyrosis and also the Loop Quantum Cosmology modified ekpyrotic model. Since our method is an approximate method, we investigate the problem at large and small curvatures. As we evince, both models yield power law reconstructed $F(R)$ gravities, with the most interesting new feature being that both lead to accelerating cosmologies, in the large curvature approximation. The mathematical properties of the some Friedmann-Robertson-Walker spacetimes $M$, that describe superbounce-like cosmologies are also pointed out, with regards to the group of curvature collineations $CC(M)$.
Optical vortex driven charge current loop and optomagnetism in fullerenes
Wätzel, Jonas; Schäffer, Alexander; Berakdar, Jamal
2016-01-01
Endohedral molecular magnets, e.g. as realized in fullerenes containing $\\rm DySc_{2}N$, are promising candidates for molecular electronics and quantum information processing. For their functionalization an ultrafast local magnetization control is essential. Using full ab-initio quantum chemistry calculations we predict the emergence of charge current loops in fullerenes with an associated orbital magnetic moment upon irradiation with weak light vortex pulses that transfer orbital angular momentum. The generated current is controllable by the frequency, the vortex topological charge, and the intensity of the light. Numerical and analytical results show that an ultraviolet vortex femtosecond pulse with an intensity $\\sim10^{13}$ W/cm$^2$ generates non-invasively nA unidirectional surface current with an associated magnetic field of hundreds $\\mu$T at the center of the fullerene.
Path Integral and Effective Hamiltonian in Loop Quantum Cosmology
Haiyun Huang; Yongge Ma; Li Qin
2011-06-27
We study the path integral formulation of Friedmann universe filled with a massless scalar field in loop quantum cosmology. All the isotropic models of $k=0,+1,-1$ are considered. To construct the path integrals in the timeless framework, a multiple group-averaging approach is proposed. Meanwhile, since the transition amplitude in the deparameterized framework can be expressed in terms of group-averaging, the path integrals can be formulated for both deparameterized and timeless frameworks. Their relation is clarified. It turns out that the effective Hamiltonian derived from the path integral in deparameterized framework is equivalent to the effective Hamiltonian constraint derived from the path integral in timeless framework, since they lead to same equations of motion. Moreover, the effective Hamiltonian constraints of above models derived in canonical theory are confirmed by the path integral formulation.
NLO evolution of 3-quark Wilson loop operator
Balitsky, I. [Old Dominion Univ., Norfolk, VA (United States) Dept. of Physics; Grabovsky, A. V. [Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP)
2015-01-01
It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.
Hanford Tank Farms Waste Certification Flow Loop Test Plan
Bamberger, Judith A.; Meyer, Perry A.; Scott, Paul A.; Adkins, Harold E.; Wells, Beric E.; Blanchard, Jeremy; Denslow, Kayte M.; Greenwood, Margaret S.; Morgen, Gerald P.; Burns, Carolyn A.; Bontha, Jagannadha R.
2010-01-01
A future requirement of Hanford Tank Farm operations will involve transfer of wastes from double shell tanks to the Waste Treatment Plant. As the U.S. Department of Energy contractor for Tank Farm Operations, Washington River Protection Solutions anticipates the need to certify that waste transfers comply with contractual requirements. This test plan describes the approach for evaluating several instruments that have potential to detect the onset of flow stratification and critical suspension velocity. The testing will be conducted in an existing pipe loop in Pacific Northwest National Laboratory’s facility that is being modified to accommodate the testing of instruments over a range of simulated waste properties and flow conditions. The testing phases, test matrix and types of simulants needed and the range of testing conditions required to evaluate the instruments are described
Simplifying one-loop amplitudes in superstring theory
Massimo Bianchi; Dario Consoli
2015-08-03
We show that 4-point vector boson one-loop amplitudes, computed in ref.[1] in the RNS formalism, around vacuum configurations with open unoriented strings, preserving at least N=1 SUSY in D=4, satisfy the correct supersymmetry Ward identities, in that they vanish for non MHV configurations (++++) and (-+++). In the MHV case (--++) we drastically simplify their expressions. We then study factorisation and the limiting IR and UV behaviour and find some unexpected results. In particular no massless poles are exposed at generic values of the modular parameter. Relying on the supersymmetric properties of our bosonic amplitudes, we extend them to manifestly supersymmetric super-amplitudes and compare our results with those obtained in the D=4 hybrid formalism, pointing out difficulties in reconciling the two approaches for contributions from N=1,2 sectors.
NLO evolution of 3-quark Wilson loop operator
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Balitsky, I.; Grabovsky, A. V.
2015-01-07
It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in themore »next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. Thus we also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.« less
Bimetallic Fe-Ni Oxygen Carriers for Chemical Looping Combustion
Bhavsar, Saurabh; Veser, Goetz
2013-11-06
The relative abundance, low cost, and low toxicity of iron make Fe-based oxygen carriers of great interest for chemical looping combustion (CLC), an emerging technology for clean and efficient combustion of fossil and renewable fuels. However, Fe also shows much lower reactivity than other metals (such as Ni and Cu). Here, we demonstrate strong improvement of Fe-based carriers by alloying the metal phase with Ni. Through a combination of carrier synthesis and characterization with thermogravimetric and fixed-bed reactor studies, we demonstrate that the addition of Ni results in a significant enhancement in activity as well as an increase in selectivity for total oxidation. Furthermore, comparing alumina and ceria as support materials highlights the fact that reducible supports can result in a strong increase in oxygen carrier utilization.
Casting Loop Quantum Cosmology in the Spin Foam Paradigm
Abhay Ashtekar; Miguel Campiglia; Adam Henderson
2010-04-03
The goal of spin foam models is to provide a viable path integral formulation of quantum gravity. Because of background independence, their underlying framework has certain novel features that are not shared by path integral formulations of familiar field theories in Minkowski space. As a simple viability test, these features were recently examined through the lens of loop quantum cosmology (LQC). Results of that analysis, reported in a brief communication [1], turned out to provide concrete arguments in support of the spin foam paradigm. We now present detailed proofs of those results. Since the quantum theory of LQC models is well understood, this analysis also serves to shed new light on some long standing issues in the spin foam and group field theory literature. In particular, it suggests an intriguing possibility for addressing the question of why the cosmological constant is positive and small.
Renormalization of a two-loop neutrino mass model
Babu, K. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States); Julio, J. [Fisika LIPI, Kompleks Puspiptek Serpong, Tangerang 15310, Indonesia and Jožef Stefan Institute, Jamova Cesta 39, 1001 Ljubljana (Slovenia)
2014-01-01
We analyze the renormalization group structure of a radiative neutrino mass model consisting of a singly charged and a doubly charged scalar fields. Small Majorana neutrino masses are generated by the exchange of these scalars via two-loop diagrams. We derive boundedness conditions for the Higgs potential and show how they can be satisfied to energies up to the Planck scale. Combining boundedness and perturbativity constraints with neutrino oscillation phenomenology, new limits on the masses and couplings of the charged scalars are derived. These in turn lead to lower limits on the branching ratios for certain lepton flavor violating (LFV) processes such as ??e?, ??3e and ? – e conversion in nuclei. Improved LFV measurements could test the model, especially in the case of inverted neutrino mass hierarchy where these are more prominent.
Loop quantum cosmology and the fate of cosmological singularities
Singh, Parampreet
2015-01-01
Singularities in general relativity such as the big bang and big crunch, and exotic singularities such as the big rip are the boundaries of the classical spacetimes. These events are marked by a divergence in the curvature invariants and the breakdown of the geodesic evolution. Recent progress on implementing techniques of loop quantum gravity to cosmological models reveals that such singularities may be generically resolved because of the quantum gravitational effects. Due to the quantum geometry, which replaces the classical differential geometry at the Planck scale, the big bang is replaced by a big bounce without any assumptions on the matter content or any fine tuning. In this manuscript, we discuss some of the main features of this approach and the results on the generic resolution of singularities for the isotropic as well as anisotropic models. Using effective spacetime description of the quantum theory, we show the way quantum gravitational effects lead to the universal bounds on the energy density, ...
Simplifying one-loop amplitudes in superstring theory
Bianchi, Massimo
2015-01-01
We show that 4-point vector boson one-loop amplitudes, computed in ref.[1] in the RNS formalism, around vacuum configurations with open unoriented strings, preserving at least N=1 SUSY in D=4, satisfy the correct supersymmetry Ward identities, in that they vanish for non MHV configurations (++++) and (-+++). In the MHV case (--++) we drastically simplify their expressions. We then study factorisation and the limiting IR and UV behaviour and find some unexpected results. In particular no massless poles are exposed at generic values of the modular parameter. Relying on the supersymmetric properties of our bosonic amplitudes, we extend them to manifestly supersymmetric super-amplitudes and compare our results with those obtained in the D=4 hybrid formalism, pointing out difficulties in reconciling the two approaches for contributions from N=1,2 sectors.
Laser Safety Method For Duplex Open Loop Parallel Optical Link
Baumgartner, Steven John (Zumbro Falls, MN); Hedin, Daniel Scott (Rochester, MN); Paschal, Matthew James (Rochester, MN)
2003-12-02
A method and apparatus are provided to ensure that laser optical power does not exceed a "safe" level in an open loop parallel optical link in the event that a fiber optic ribbon cable is broken or otherwise severed. A duplex parallel optical link includes a transmitter and receiver pair and a fiber optic ribbon that includes a designated number of channels that cannot be split. The duplex transceiver includes a corresponding transmitter and receiver that are physically attached to each other and cannot be detached therefrom, so as to ensure safe, laser optical power in the event that the fiber optic ribbon cable is broken or severed. Safe optical power is ensured by redundant current and voltage safety checks.
Closed loop computer control for an automatic transmission
Patil, Prabhakar B. (Detroit, MI)
1989-01-01
In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determined from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.
Noise Analysis of ClosedLoop Vibratory Rate Gyros Dennis Kim and Robert M'Closkey
M'Closkey, Robert T.
Noise Analysis of ClosedLoop Vibratory Rate Gyros Dennis Kim and Robert M'Closkey Mechanical detailed noise analysis of closedloop MEMS vibratory gyros whose noise characteristics are dominated by the mechanicalthermal noise of the sensor's vibrating structure as well as the electrical noise associated
Evaluating the Health of California's Loop Sensor Network Ram Rajagopal1 and Pravin Varaiya
Varaiya, Pravin
Evaluating the Health of California's Loop Sensor Network Ram Rajagopal1 and Pravin Varaiya The California Department of Transportation (Caltrans) freeway sensor network has two compo- nents: the sensor system of 25,000 inductive loop sensors grouped into 8,000 vehicle detector sta- tions (VDS) and covering
Loop induced interference effects in Higgs Boson plus two jet production at the LHC.
Andersen, Jeppe R.; Binoth, T.; Heinrich, G.; Smillie, Jennifer M.
We calculate the order O(?2?3 s) interference effect between the gluon fusion and weak boson fusion processes allowed at the one-loop level in Higgs boson plus 2 jet production at the LHC. The corresponding one-loop amplitudes, which have...
Wang, Jiandong
Quantification of Valve Stiction for Control Loop Performance Assessment Guohua Wang and liandong, Beijing, P. R. China (*Email: jiandong@pku.edu.cn) Abstract - Control valves are extensively used in the process industry and valve stiction limits the performance of control loops. This study aims
Boyer, Edmond
Relativistic calculation of the pion loop correlation energy in nuclear matter in a theory of nuclear matter which contains the correlation energy. Pion loops are incorporated on top of a relativistic for the correlation energy is the Landau-Migdal parameter g governing the short-range part of the spin- isospin
Chronopoulos, Anthony T.
runs within this network of computing resources to allow for inter-process communication between the various resources by use of Message Passing Interface (MPI). Scientific applications usually consist of large loops (re- peated execution of a set of statements) inside them. These loops are one
On the Location of Energy Release and Temperature Pro les along Coronal Loops
Mackay, Duncan
temperature and the temperature distribution along the loop. In each case the ratio between the heat deposited and radiation provides a scaling for the summit temperature. Keywords: methods: Numerical - MHD - sun: corona;les of the energy release are then used to in- vestigate the temperature distribution along a loop.
2102, Page 1 Experimental Investigation of Closed Loop Oscillating Heat Pipe as the
Ghajar, Afshin J.
2102, Page 1 Experimental Investigation of Closed Loop Oscillating Heat Pipe as the Condenser The aim of this article is to experimentally investigate the application of a closed loop oscillating heat pipe (CLOHP) as the condenser for a vapor compression refrigeration system. Split type air conditioner
Roadmap to Realistic Modeling of Closed Loop Pulsating Heat Pipes Sameer Khandekar
Khandekar, Sameer
Roadmap to Realistic Modeling of Closed Loop Pulsating Heat Pipes Sameer Khandekar§ and Manfred modeling of pulsating heat pipes through `first' principles is a contemporary problem which remains quite is presented which is based on the fact that at high enough heat flux level, Closed Loop Pulsating Heat Pipes
Operational limit of closed loop pulsating heat pipes Honghai Yang a,*, S. Khandekar b
Khandekar, Sameer
Operational limit of closed loop pulsating heat pipes Honghai Yang a,*, S. Khandekar b , M. Groll c an experimental study on the operational limitation of closed loop pulsating heat pipes (CLPHPs), which consist pipes; Performance limit; Dry-out 1. Introduction Pulsating heat pipes (PHPs) or oscillating heat pipes
Closed loop pulsating heat pipes Part B: visualization and semi-empirical modeling
Khandekar, Sameer
Closed loop pulsating heat pipes Part B: visualization and semi-empirical modeling Sameer Khandekar May 2003 Abstract Pulsating heat pipes have received growing attention from experimental performance results of a fairly large matrix of closed loop pulsating heat pipes. This paper, which
Scaling of hybrid-electric vehicle powertrain components for Hardware-in-the-loop simulation
Brennan, Sean
Scaling of hybrid-electric vehicle powertrain components for Hardware-in-the-loop simulation: Hardware-in-the-loop Hybrid electric vehicle Buckingham Pi Theorem Battery model a b s t r a c t Hardware to correctly scale electric vehicle components, particularly the following subsystems: electric motor
Free energy for parameterized Polyakov loops in SU(2) and SU(3) lattice gauge theory
Rossak, Wilhelm R.
Free energy for parameterized Polyakov loops in SU(2) and SU(3) lattice gauge theory [arXiv:1205 by analyzing the free energy of static quarks in pure SU(2) and SU(3) lattice gauge theory. The Polyakov loop P is introduced as a parameterized source for the quarks. Calculation of the free energy F as a function
Structure and Stability of EUV Loops Originating from G. Peres and S. Orlando
SOHO and the relevant data interpretation. Neither hydrostatic, nor siphon flow loop plasma models hydrostatic or Â better Â undergoing a siphon flow. These results may be evidence of dynamic conditions in EUV as the left panel for for the siphon flow loop model of Orlando et al. (1995), in critical conditions
Models of stationary siphon flows in stratified, thermally conducting coronal loops: II Â Shocked to explore the conditions for the presence of stationary shocks in critical and supersonic siphon flows of stationary siphon flows in a semicircular solar coronal loop of constant cross section. The model was based
PROPERTIES OF THE ACCELERATION REGIONS IN SEVERAL LOOP-STRUCTURED SOLAR FLARES
Piana, Michele
PROPERTIES OF THE ACCELERATION REGIONS IN SEVERAL LOOP-STRUCTURED SOLAR FLARES Jingnan Guo1 , A-energy electrons accelerated in solar flares is the hard X-ray bremsstrahlung that they produce as they propagate et al. (2008) analyzed a set of extended coronal flare loops located near the solar limb, and were
Equivalence of Two-Loop Superstring Amplitudes in the Pure Spinor and RNS Formalisms
Nathan Berkovits; Carlos R. Mafra
2005-10-14
The pure spinor formalism for the superstring has recently been used to compute massless four-point two-loop amplitudes in a manifestly super-Poincare covariant manner. In this paper, we show that when all four external states are Neveu-Schwarz, the two-loop amplitude coincides with the RNS result.
Equivalence of Two-Loop Superstring Amplitudes in the Pure Spinor and RNS Formalisms
Berkovits, N; Berkovits, Nathan; Mafra, Carlos R.
2006-01-01
The pure spinor formalism for the superstring has recently been used to compute massless four-point two-loop amplitudes in a manifestly super-Poincare covariant manner. In this paper, we show that when all four external states are Neveu-Schwarz, the two-loop amplitude coincides with the RNS result.
The impact of a filament eruption on nearby high-lying cool loops
Harra, L. K.; Matthews, S. A.; Long, D. M.; Doschek, G. A.; De Pontieu, B.
2014-09-10
The first spectroscopic observations of cool Mg II loops above the solar limb observed by NASA's Interface Region Imaging Spectrograph (IRIS) are presented. During the observation period, IRIS is pointed off-limb, allowing the observation of high-lying loops, which reach over 70 Mm in height. Low-lying cool loops were observed by the IRIS slit-jaw camera for the entire four-hour observing window. There is no evidence of a central reversal in the line profiles, and the Mg II h/k ratio is approximately two. The Mg II spectral lines show evidence of complex dynamics in the loops with Doppler velocities reaching ±40 km s{sup –1}. The complex motions seen indicate the presence of multiple threads in the loops and separate blobs. Toward the end of the observing period, a filament eruption occurs that forms the core of a coronal mass ejection. As the filament erupts, it impacts these high-lying loops, temporarily impeding these complex flows, most likely due to compression. This causes the plasma motions in the loops to become blueshifted and then redshifted. The plasma motions are seen before the loops themselves start to oscillate as they reach equilibrium following the impact. The ratio of the Mg h/k lines also increases following the impact of the filament.
Assessment of Proportional-Integral Control Loop Performance for Input Load Disturbance Rejection
Wang, Jiandong
Assessment of Proportional-Integral Control Loop Performance for Input Load Disturbance Rejection: This paper studies the performance assessment of proportional-integral (PI) control loops in terms and to demonstrate the effectiveness of the proposed performance index. 1. INTRODUCTION Proportional
Process/Equipment Co-Simulation on Syngas Chemical Looping Process
Zeng, Liang; Zhou, Qiang; Fan, Liang-Shih
2012-09-30
The chemical looping strategy for fossil energy applications promises to achieve an efficient energy conversion system for electricity, liquid fuels, hydrogen and/or chemicals generation, while economically separate CO{sub 2} by looping reaction design in the process. Chemical looping particle performance, looping reactor engineering, and process design and applications are the key drivers to the success of chemical looping process development. In order to better understand and further scale up the chemical looping process, issues such as cost, time, measurement, safety, and other uncertainties need to be examined. To address these uncertainties, advanced reaction/reactor modeling and process simulation are highly desired and the modeling efforts can accelerate the chemical looping technology development, reduce the pilot-scale facility design time and operating campaigns, as well as reduce the cost and technical risks. The purpose of this work is thus to conduct multiscale modeling and simulations on the key aspects of chemical looping technology, including particle reaction kinetics, reactor design and operation, and process synthesis and optimization.
AUTOMATIC LOOP-SHAPING OF QFT CONTROLLERS VIA LINEAR PROGRAMMING1
Massachusetts at Amherst, University of
AUTOMATIC LOOP-SHAPING OF QFT CONTROLLERS VIA LINEAR PROGRAMMING1 Yossi Chait2 Qian Chen3 and C-time QFT users, there is a genuine need for an automatic loop-shaping tool to generate a first-cut solution. Clearly, such an automatic process must involve some sort of optimization, and, while recent results
Dynamic Magnetography of Solar Flaring Loops Gregory D. Fleishman1,2
) demonstrated that the mean magnetic field in a solar flare derived from the microwave spectrum yields resultsDynamic Magnetography of Solar Flaring Loops Gregory D. Fleishman1,2 , Gelu M. Nita1 , Dale E. Gary with shaking, which allows the derivation of the magnetic field and other parameters along a solar flaring loop
APPLICATION OF GENEALOGICAL DECISION TREES FOR OPEN-LOOP TRACKING CONTROL
Del Moral , Pierre
APPLICATION OF GENEALOGICAL DECISION TREES FOR OPEN-LOOP TRACKING CONTROL Enso Ikonen !,1 Kaddour on a genealogical decision tree is suggested for solving an open-loop tracking problem. The algorithm associates supported by UK EPSRC Research cluster project, grant nro GR/S63779/01 Genealogical decision trees belong
Asymptotic scaling corrections in QCD with Wilson fermions from the 3-loop average plaquette
B. Alles; A. Feo; H. Panagopoulos
1998-01-23
We calculate the 3-loop perturbative expansion of the average plaquette in lattice QCD with N_f massive Wilson fermions and gauge group SU(N). The corrections to asymptotic scaling in the corresponding energy scheme are also evaluated. We have also improved the accuracy of the already known pure gluonic results at 2 and 3 loops.
Thermal and non-thermal emission from reconnecting twisted coronal loops
Pinto, R; Browning, P K; Vilmer, N
2015-01-01
Twisted magnetic fields should be ubiquitous in the solar corona. The magnetic energy contained in such twisted fields can be released during solar flares and other explosive phenomena. Reconnection in helical magnetic coronal loops results in plasma heating and particle acceleration distributed within a large volume, including the lower coronal and chromospheric sections of the loops, and can be a viable alternative to the standard flare model, where particles are accelerated only in a small volume located in the upper corona. The goal of this study is to investigate the observational signatures of plasma heating and particle acceleration in kink-unstable twisted coronal loops using combination of MHD simulations and test-particle methods. The simulations describe the development of kink instability and magnetic reconnection in twisted coronal loops using resistive compressible MHD, and incorporate atmospheric stratification and large-scale loop curvature. The resulting distributions of hot plasma let us est...
Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate
Mittereder, Nick; Poerschke, Andrew
2013-11-01
This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season.
Coupling of pion condensate, chiral condensate and Polyakov loop in an extended NJL model
Zhao Zhang; Yu-Xin Liu
2007-05-09
The Nambu Jona-Lasinio model with a Polyakov loop is extended to finite isospin chemical potential case, which is characterized by simultaneous coupling of pion condensate, chiral condensate and Polyakov loop. The pion condensate, chiral condensate and the Polyakov loop as functions of temperature and isospin chemical potential are investigated by minimizing the thermodynamic potential of the system. The resulting $(T,\\mu_I)$ phase diagram is studied with emphasis on the critical point and Polyakov loop dynamics. The tricritical point for the pion superfluidity phase transition is confirmed and the phase transition for isospin symmetry restoration in high isospin chemical potential region perfectly coincides with the crossover phase transition for Polyakov loop. These results are in agreement with the Lattice QCD data.
Modeling solar coronal bright point oscillations with multiple nanoflare heated loops
Chandrashekhar, K
2015-01-01
Intensity oscillations of coronal bright points (BPs) have been studied for past several years. It has been known for a while that these BPs are closed magnetic loop like structures. However, initiation of such intensity oscillations is still an enigma. There have been many suggestions to explain these oscillations, but modeling of such BPs have not been explored so far. Using a multithreaded nanoflare heated loop model we study the behavior of such BPs in this work. We compute typical loop lengths of BPs using potential field line extrapolation of available data (Chandrashekhar et al. 2013), and set this as the length of our simulated loops. We produce intensity like observables through forward modeling and analyze the intensity time series using wavelet analysis, as was done by previous observers. The result reveals similar intensity oscillation periods reported in past observations. It is suggested these oscillations are actually shock wave propagations along the loop. We also show that if one considers di...
Farahania, N Darestani
2015-01-01
A formulation of a multi-input single-output closed-loop subspace system identification method is employed for the purpose of obtaining control-relevant model of the vacuum-plasma response in Damavand tokamak. Such a model is particularly well suited for robust controller design. The accuracy of the estimate of the plant dynamics is estimated by different experiments. The method described in this paper is a worst-case identification technique, in that it aims to minimize the error between the identified model and the true plant. The identified model fitness around defined operating point is more than 90% and with comparison by physical-based model it has better root mean square measure of the goodness of the fit.
DEEPER BY THE DOZEN: UNDERSTANDING THE CROSS-FIELD TEMPERATURE DISTRIBUTIONS OF CORONAL LOOPS
Schmelz, J. T.; Pathak, S.; Jenkins, B. S.; Worley, B. T., E-mail: jschmelz@memphis.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)
2013-02-10
Spectroscopic analysis of coronal loops has revealed a variety of cross-field temperature distributions. Some loops appear to be isothermal while others require multithermal plasma. The EUV Imaging Spectrometer on Hinode has the spatial resolution and temperature coverage required for differential emission measure (DEM) analysis of coronal loops. Our results also use data from the X-Ray Telescope on Hinode as a high-temperature constraint. Of our 12 loops, two were post-flare loops with broad temperature distributions, two were narrow but not quite isothermal, and the remaining eight were in the mid range. We consider our DEM methods to be a significant advance over previous work, and it is also reassuring to learn that our findings are consistent with results available in the literature. For the quiescent loops analyzed here, 10 MK plasma, a signature of nanoflares, appears to be absent at a level of approximately two orders of magnitude down from the DEM peak. We find some evidence that warmer loops require broader DEMs. The cross-field temperatures obtained here cannot be modeled as single flux tubes. Rather, the observed loop must be composed of several or many unresolved strands. The plasma contained in each of these strands could be cooling at different rates, contributing to the multithermal nature of the observed loop pixels. An important implication of our DEM results involves observations from future instruments. Once solar telescopes can truly resolve X-ray and EUV coronal structures, these images would have to reveal the loop substructure implied by our multithermal results.
Unresolved fine-scale structure in solar coronal loop-tops
Scullion, E.; Van der Voort, L. Rouppe; Wedemeyer, S.; Antolin, P.
2014-12-10
New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal loop substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric H? 656.28 nm spectral line core and wings can, under certain circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal loops, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in H?) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal loop-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from loop-top to footpoint. We discover that coronal loop fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal loop cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal loops, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal loops.
Ozcan, Dursun Can
2014-11-27
The first detailed systematic investigation of a cement plant with various carbon capture technologies has been performed. The calcium looping (Ca-looping) process has emerged as a leading option for this purpose, since ...
Vallino, Joseph J.
the flow of energy and mass to higher trophic levels via the postulated microbial loop. In orderMicrobial Grazing Lab The microbial loop is responsible for the cycling of nutrients as well
Optimization of the GB/SA Solvation Model for Predicting the Structure of Surface Loops in Proteins
Meirovitch, Hagai
to the training group as well as to a "test" group of seven loops, and the energy gaps and the corresponding RMSD parameter, (programmed in the TINKER package) are reoptimized for a "training" group of nine loops
Green, Michael
2014-01-01
Limitations on a Thermal Siphon 4 K Helium Loop for Cooling-using a Hydrogen Thermal Siphon Loop and Coolers operatingdescribes the kind of thermal siphon cooling loop that can
An Apparent Relation between ELM Occurrence Times and the Prior Phase Evolution of Divertor Flux Loop Measurements in JET
Holland, Marika; Bailey, David A 54 ENVIRONMENTAL SCIENCES The...
Office of Scientific and Technical Information (OSTI)
states. This document provides the agenda and list of participants for the conference. Web materials for all lectures and practical sessions available from: http:...
Trusted Virtual Containers on Demand Katelin A. Bailey
Smith, Sean W.
An Analysis of Chaining Protocols for Video-on-Demand Jehan-François Pâris Department of Computer@ucu.edu.uy Abstract--Chaining protocols for video-on-demand require each client to forward the video data it receives on demand by involving clients in the video distribution process. Chaining organizes all clients watching
Weakly neighbour-balanced designs R. A. Bailey
Bailey, R. A.
1 ... 0 6 5 4 3 2 1 2/11 #12;Small example: each treatment comes "once" per block Wind 6 ... 0 1 2 upwind of j 2/11 #12;Small example: each treatment comes "once" per block Wind 6 ... 0 1 2 3 4 5 6 5 2/11 #12;Small example: each treatment comes "once" per block Wind 6 ... 0 1 2 3 4 5 6 5 ... 0 2 4
In uence-Based Model Decomposition Christopher Bailey-Kellogg
Bailey-Kellogg, Chris
building temperature (smart buildings) to ve- hicle on-board diagnostic and control systems that in- cessing technology have enabled a new generation of AI robotic systems | so-called Smart Matter systems of these Smart Matter systems is to synthesize optimal control policies using data rich models for the systems
Seating Final Exam, Fall 2011, Bailey classes, Lambert Fieldhouse
Bailey, Charlotte M
2011-12-07
Seating Final Exam, Fall 2011, KLOSTER classes, Lambert. Fieldhouse. NAME. ROW. SEAT NUMBER. Arrington, Brook L. 1. 1. Blevins, Sash M. 2. 1. Brown ...
The HPC Challenge (HPCC) Benchmark Suite Piotr Luszczek, David Bailey,
Tennessee, University of
flops on each list per vendor Use external metrics: price, ownership cost, power, ... Focus System Design ReviewIndustry Milestones Productivity Assessment (MIT LL, DOE, DoD, NASA, NSF) MP Peta Mission Partners Mission Partner Peta-Scale Application Dev 11 Final Demo SW Rel 1 SCR SW Rel 2 SW Rel 3
Randomization 50 years after Fisher R. A. Bailey
Bailey, R. A.
of the different points of view. 2/36 #12;A lady tasting tea " A lady declares that by tasting a cup of tea made with milk she can discriminate whether the milk or the tea infusion was first added to the cup." (Fisher, Design of Experiments, 1935) 3/36 #12;A lady tasting tea " A lady declares that by tasting a cup of tea
University of Alaska Jason Bailey Home 907 746 5117
Mock, Kenrick
from a single drilling pad. Allowing oil companies to cut production costs and pipeline expenses while ...........................................................................15 Page 2 #12;Introduction Modern oil well drilling techniques involve a process known as directional drilling, which is a method of deviating the well from a vertical inclination and steering it towards
Field Mapping At Valles Caldera - Sulphur Springs Geothermal Area (Bailey,
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 SECTIONRobertsdale, AlabamaETEC GmbHFarinello GeothermalFideris Inc formerly1-2003)Emidio Desert1969)Et
Microsoft PowerPoint - Continued Storage Rule_Marissa Bailey
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 GasAdministration Medal01 Sandia4) AugustA. -71-3OverviewAustralian NuclearContinued
Bailey Bay Hot Springs Geothermal Area | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowaWisconsin: EnergyYorkColorado State Office
Benmei, Chen
Design and implementation of a hardware-in-the-loop simulation system for small-scale UAV: Hardware-in-the-loop simulation UAV Helicopter Flight control a b s t r a c t We present in the paper constructed unmanned-aerial-vehicle (UAV) helicopter systems. Real-time hardware-in-the-loop simulation is one
Page 1 of 31 Why does the Loop Current tend to shed more eddies in summer and winter?1
Page 1 of 31 Why does the Loop Current tend to shed more eddies in summer and winter?1 Y.-L. Chang seasonal preferences of Loop Current eddy shedding, more in summer and5 winter and less in fall and spring in virtually any21 month of the year. That the Loop Current can intrude into the Gulf and eddies can separate
Effects of winds and Caribbean eddies on the frequency of Loop Current eddy shedding: A numerical of Mexico, Caribbean Current, Loop Current, eddy shedding, winds and eddies, numerical ocean model Citation of Loop Current eddy shedding: A numerical model study, J. Geophys. Res., 108(C10), 3324, doi:10
Non-Destructive Testing with Neutron Radiography at the UC Davis/ McClellan Nuclear Radiation Center
Boussoufi, M.; Steingass, W.; Egbert, H.; Liu, H. B.; Flocchini, R.
2006-01-01
level corrosion and hidden defects in aircraft structurescastings for aircraft. # Looking for corrosion/corrosion
Non-Destructive Testing with Neutron Radiography at the UC Davis/ McClellan Nuclear Radiation Center
Boussoufi, M.; Steingass, W.; Egbert, H.; Liu, H. B.; Flocchini, R.
2006-01-01
personnel shield) and a separate * The tank-wall sectionin-tank section • Each beam tube ends with a bulk shield (
Non-Destructive Testing with Neutron Radiography at the UC Davis/ McClellan Nuclear Radiation Center
Boussoufi, M.; Steingass, W.; Egbert, H.; Liu, H. B.; Flocchini, R.
2006-01-01
for research and non-destructive testing projects. • OurNon-Destructive Testing with Neutron Radiography M.
Cool transition region loops observed by the Interface Region Imaging Spectrograph
Huang, Zhenghua; Li, Bo; Madjarska, Maria S
2015-01-01
We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops. This class of loops has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si IV 1402.8 \\AA\\ spectral raster and 1400 \\AA\\ slit-jaw (SJ) images. We divide the loops into three groups and study their dynamics and interaction. The first group comprises relatively stable loops, with 382--626\\,km cross-sections. Observed Doppler velocities are suggestive of siphon flows, gradually changing from -10 km/s at one end to 20 km/s at the other end of the loops. Nonthermal velocities from 15 to 25 km/s were determined. These physical properties suggest that these loops are impulsively heated by magnetic reconnection occurring at the blue-shifted footpoints where magnetic cancellation with a rate of $10^{15}$ Mx/s is found. The released magnetic energy is redistributed by the siphon flows. The second group corresponds to two footpoin...
DETECTING NANOFLARE HEATING EVENTS IN SUBARCSECOND INTER-MOSS LOOPS USING Hi-C
Winebarger, Amy R.; Moore, Ronald; Cirtain, Jonathan; Walsh, Robert W.; De Pontieu, Bart; Title, Alan; Hansteen, Viggo; Golub, Leon; Korreck, Kelly; Weber, Mark; Kobayashi, Ken; DeForest, Craig; Kuzin, Sergey
2013-07-01
The High-resolution Coronal Imager (Hi-C) flew aboard a NASA sounding rocket on 2012 July 11 and captured roughly 345 s of high-spatial and temporal resolution images of the solar corona in a narrowband 193 A channel. In this paper, we analyze a set of rapidly evolving loops that appear in an inter-moss region. We select six loops that both appear in and fade out of the Hi-C images during the short flight. From the Hi-C data, we determine the size and lifetimes of the loops and characterize whether these loops appear simultaneously along their length or first appear at one footpoint before appearing at the other. Using co-aligned, co-temporal data from multiple channels of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory, we determine the temperature and density of the loops. We find the loops consist of cool ({approx}10{sup 5} K), dense ({approx}10{sup 10} cm{sup -3}) plasma. Their required thermal energy and their observed evolution suggest they result from impulsive heating similar in magnitude to nanoflares. Comparisons with advanced numerical simulations indicate that such dense, cold and short-lived loops are a natural consequence of impulsive magnetic energy release by reconnection of braided magnetic field at low heights in the solar atmosphere.
More on loops in reheating: non-gaussianities and tensor power spectrum
Katirci, Nihan; Kaya, Ali; Tarman, Merve E-mail: ali.kaya@boun.edu.tr
2014-06-01
We consider the single field chaotic m{sup 2}?{sup 2} inflationary model with a period of preheating, where the inflaton decays to another scalar field ? in the parametric resonance regime. In a recent work, one of us has shown that the ? modes circulating in the loops during preheating notably modify the (??) correlation function. We first rederive this result using a different gauge condition hence reconfirm that superhorizon ? modes are affected by the loops in preheating. Further, we examine how ? loops give rise to non-gaussianity and affect the tensor perturbations. For that, all cubic and some higher order interactions involving two ? fields are determined and their contribution to the non-gaussianity parameter f{sub NL} and the tensor power spectrum are calculated at one loop. Our estimates for these corrections show that while a large amount of non-gaussianity can be produced during reheating, the tensor power spectrum receive moderate corrections. We observe that the loop quantum effects increase with more ? fields circulating in the loops indicating that the perturbation theory might be broken down. These findings demonstrate that the loop corrections during reheating are significant and they must be taken into account for precision inflationary cosmology.
Testing a Riemannian twisted solar loop model from EUV data and magnetic topology
Garcia de Andrade
2008-01-12
Compact Riemannian solar twisted magnetic flux tube surfaces model are tested against solar extreme ultraviolet (EUV) lines observations, allowing us to compute the diameter and height of solar plasma loops. The relation between magnetic and torsion energies is found for a nonplanar solar twisted (torsioned) loop to be $10^{9}$, which shows that the contribution of torsion energy to the solar loop is extremely weaker than the magnetic energy contribution. In this case solar loops of up $5000 km$ in diameter can be reached. The height of $220.000 km$ is used to obtain an estimate for torsion based on the Riemannian flux tube surface, which yields ${\\tau}_{0}=0.9{\\times} 10^{-8} m^{-1}$ which coincides with one of the data of $(0.9{\\pm}0.4){\\times}10^{-8}m^{-1}$ obtained by Lopez-Fuentes et al (2003). This result tells us that the Riemannian flux tube model for plasma solar loops is consistent with experimental results in solar physics. These results are obtained for a homogeneous twisted solar loop. By making use of Moffatt-Ricca theorem for the bounds on torsional energy of unknotted vortex filaments, applied to magnetic topology, one places bounds on the lengths of EUV solar loops. New results as the vorticity of the plasma flow along the tube is also computed in terms of the flux tube twist.
Loop quantum cosmology and the fate of cosmological singularities
Parampreet Singh
2015-09-30
Singularities in general relativity such as the big bang and big crunch, and exotic singularities such as the big rip are the boundaries of the classical spacetimes. These events are marked by a divergence in the curvature invariants and the breakdown of the geodesic evolution. Recent progress on implementing techniques of loop quantum gravity to cosmological models reveals that such singularities may be generically resolved because of the quantum gravitational effects. Due to the quantum geometry, which replaces the classical differential geometry at the Planck scale, the big bang is replaced by a big bounce without any assumptions on the matter content or any fine tuning. In this manuscript, we discuss some of the main features of this approach and the results on the generic resolution of singularities for the isotropic as well as anisotropic models. Using effective spacetime description of the quantum theory, we show the way quantum gravitational effects lead to the universal bounds on the energy density, the Hubble rate and the anisotropic shear. We discuss the geodesic completeness in the effective spacetime and the resolution of all of the strong singularities. It turns out that despite the bounds on energy density and the Hubble rate, there can be divergences in the curvature invariants. However such events are geodesically extendible, with tidal forces not strong enough to cause inevitable destruction of the in-falling objects.
Natural Ores as Oxygen Carriers in Chemical Looping Combustion
Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James
2013-08-01
Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).
Study of Two-Loop Neutrino Mass Generation Models
Geng, Chao-Qiang
2015-01-01
We study the models with the Majorana neutrino masses generated radiatively by two-loop diagrams due to the Yukawa $\\rho \\bar \\ell_R^c \\ell_R$ and effective $\\rho^{\\pm\\pm} W^\\mp W^\\mp$ couplings along with a scalar triplet $\\Delta$, where $\\rho$ is a doubly charged singlet scalar, $\\ell_R$ the charged lepton and $W$ the charged gauge boson. A generic feature in these types of models is that the neutrino mass spectrum has to be a normal hierarchy. Furthermore, by using the neutrino oscillation data and comparing with the global fitting result in the literature, we find a unique neutrino mass matrix and predict the Dirac and two Majorana CP phases to be $1.40\\pi$, $1.11\\pi$ and $1.47\\pi$, respectively. We also discuss the model parameters constrained by the lepton flavor violating processes and electroweak oblique parameters. In addition, we show that the rate of the neutrinoless double beta decay $(0\
Holographic Wilson loops, Hamilton-Jacobi equation and regularizations
Pontello, Diego
2015-01-01
The minimal area for surfaces whose border are rectangular and circular loops are calculated using the Hamilton-Jacobi (HJ) equation. This amounts to solve the HJ equation for the value of the minimal area, without calculating the shape of the corresponding surface. This is done for bulk geometries that are asymptotically AdS. For the rectangular countour, the HJ equation, which is separable, can be solved exactly. For the circular countour an expansion in powers of the radius is implemented. The HJ approach naturally leads to a regularization which consists in locating the countour away from the border. The results are compared with other regularization which leaves the countour at the border and calculates the area of the corresponding minimal surface up to a diameter smaller than the one of the countour at the border. The results do not coincide, this is traced back to the fact that in the former case the area of a minimal surface is calculated and in the second the computed area corresponds to a fraction ...
Holographic Wilson loops, Hamilton-Jacobi equation and regularizations
Diego Pontello; Roberto Trinchero
2015-09-21
The minimal area for surfaces whose border are rectangular and circular loops are calculated using the Hamilton-Jacobi (HJ) equation. This amounts to solve the HJ equation for the value of the minimal area, without calculating the shape of the corresponding surface. This is done for bulk geometries that are asymptotically AdS. For the rectangular countour, the HJ equation, which is separable, can be solved exactly. For the circular countour an expansion in powers of the radius is implemented. The HJ approach naturally leads to a regularization which consists in locating the countour away from the border. The results are compared with other regularization which leaves the countour at the border and calculates the area of the corresponding minimal surface up to a diameter smaller than the one of the countour at the border. The results do not coincide, this is traced back to the fact that in the former case the area of a minimal surface is calculated and in the second the computed area corresponds to a fraction of a different minimal surface whose countour lies at the boundary.
The Phoenix Project: Master Constraint Programme for Loop Quantum Gravity
Thomas Thiemann
2003-05-21
The Hamiltonian constraint remains the major unsolved problem in Loop Quantum Gravity (LQG). Seven years ago a mathematically consistent candidate Hamiltonian constraint has been proposed but there are still several unsettled questions which concern the algebra of commutators among smeared Hamiltonian constraints which must be faced in order to make progress. In this paper we propose a solution to this set of problems based on the so-called {\\bf Master Constraint} which combines the smeared Hamiltonian constraints for all smearing functions into a single constraint. If certain mathematical conditions, which still have to be proved, hold, then not only the problems with the commutator algebra could disappear, also chances are good that one can control the solution space and the (quantum) Dirac observables of LQG. Even a decision on whether the theory has the correct classical limit and a connection with the path integral (or spin foam) formulation could be in reach. While these are exciting possibilities, we should warn the reader from the outset that, since the proposal is, to the best of our knowledge, completely new and has been barely tested in solvable models, there might be caveats which we are presently unaware of and render the whole {\\bf Master Constraint Programme} obsolete. Thus, this paper should really be viewed as a proposal only, rather than a presentation of hard results, which however we intend to supply in future submissions.
Hot B violation, the lattice, and hard thermal loops
Peter Arnold
1997-01-28
It has recently been argued that the rate per unit volume of baryon number violation (topological transitions) in the hot, symmetric phase of electroweak theory is of the form $\\eta \\alpha_w^5 T^4$ in the weak-coupling limit, where $\\eta$ is a non-perturbative numerical coefficient. Over the past several years, there have been attempts to extract the rate of baryon number violation from real-time simulations of classical thermal field theory on a spatial lattice. Unfortunately, the coefficient $\\eta$ will not be the same for classical lattice theories and the real quantum theory. However, by analyzing the appropriate effective theory on the lattice using the method of hard thermal loops, I show that the only obstruction to precisely relating the rates in the real and lattice theories is the fact that the long-distance physics on the lattice is not rotationally invariant. (This is unlike Euclidean-time measurements, where rotational invariance is always recovered in the continuum limit.) I then propose how this violation of rotational invariance can be eliminated - and the real B violation rate measured - by choosing an appropriate lattice Hamiltonian. I also propose a rough measure of the systematic error to be expected from using simpler, unimproved Hamiltonians. As a byproduct of my investigation, the plasma frequency and Debye mass are computed for classical thermal field theory on the lattice.
Two-loop massive scalar three-point function in a dispersive approach
Vladyslav Pauk; Marc Vanderhaeghen
2014-11-12
We present a dispersion relation formalism to calculate a massive scalar two-loop vertex function. Such calculation is of direct relevance in the evaluation of the hadronic light-by-light contribution to the muon's anomalous magnetic moment due to meson poles. The discontinuity of the two-loop diagram is obtained by a sum of two- and three-particle cut contributions, which involve a phase space integration over the physical intermediate states. The real part of the vertex function is subsequently reconstructed through evaluation of a dispersion integral. We explicitly demonstrate that the dispersive formalism yields exactly the same result as the direct two-loop calculation.
Dual quark condensate in the Polyakov-loop extended Nambu--Jona-Lasinio model
Kouji Kashiwa; Hiroaki Kouno; Masanobu Yahiro
2009-12-09
The dual quark condensate $\\Sigma^{(n)}$ proposed recently as a new order parameter of the spontaneous breaking of the ${\\mathbb Z}_3$ symmetry are evaluated by the Polyakov-loop extended Nambu--Jona-Lasinio model, where $n$ are winding numbers. The Polyakov-loop extended Nambu--Jona-Lasinio model well reproduces lattice QCD data on $\\Sigma^{(1)}$ measured very lately. The dual quark condensate $\\Sigma^{(n)}$ at higher temperatures is sensitive to the strength of the vector-type four-quark interaction in the Polyakov-loop extended Nambu--Jona-Lasinio model and hence a good quantity to determine the strength.
Two Loop Renormalization of Massive (p,q) Supersymmetric Sigma Models
N. D. Lambert
1995-10-18
We calculate the beta-functions of the general massive (p,q) supersymmetric sigma model to two loop order using (1,0) superfields. The conditions for finiteness are discussed in relation to (p,q) supersymmetry. We also calculate the effective potential using component fields to one loop order and consider the possibility of perturbative breaking of supersymmetry. The effect of one loop finite local counter terms and the ultra-violet behaviour of the off-shell (p,q) models to all orders in perturbation theory are also addressed.
Higher Rank Wilson Loops in N = 2* Super-Yang-Mills Theory
Xinyi Chen-Lin; Konstantin Zarembo
2015-02-13
The N=2* Super-Yang-Mills theory (SYM*) undergoes an infinite sequence of large-N quantum phase transitions. We compute expectation values of Wilson loops in k-symmetric and antisymmetric representations of the SU(N) gauge group in this theory and show that the same phenomenon that causes the phase transitions at finite coupling leads to a non-analytic dependence of Wilson loops on k/N when the coupling is strictly infinite, thus making the higher-representation Wilson loops ideal holographic probes of the non-trivial phase structure of SYM*.
On secondary loops in LAOS via self-intersection of Lissajous–Bowditch curves
Ewoldt, Randy H.
When the shear stress measured in large amplitude oscillatory shear (LAOS) deformation is represented as a 2-D Lissajous–Bowditch curve, the corresponding trajectory can appear to self-intersect and form secondary loops. ...
Development of a compensation chamber for use in a multiple condenser loop heat pipe
Roche, Nicholas Albert
2013-01-01
The performance of many electronic devices is presently limited by heat dissipation rates. One potential solution lies in high-performance air-cooled heat exchangers like PHUMP, the multiple condenser loop heat pipe presented ...
Design, fabrication, and characterization of a multi-condenser loop heat pipe
Hanks, Daniel Frank
2012-01-01
A condenser design was characterized for a multi-condenser loop heat pipe (LHP) capable of dissipating 1000 W. The LHP was designed for integration into a high performance aircooled heat sink to address thermal management ...
Shin, J; Kim, W K; Metzler, R
2015-01-01
We study the dynamics of polymer chains in a bath of self-propelled particles (SPP) by extensive Langevin dynamics simulations in a two dimensional system. Specifically, we analyse the polymer looping properties versus the SPP activity and investigate how the presence of the active particles alters the chain conformational statistics. We find that SPPs tend to extend flexible polymer chains while they rather compactify stiffer semiflexible polymers, in agreement with previous results. Here we show that larger activities of SPPs yield a higher effective temperature of the bath and thus facilitate looping kinetics of a passive polymer chain. We explicitly compute the looping probability and looping time in a wide range of the model parameters. We also analyse the motion of a monomeric tracer particle and the polymer's centre of mass in the presence of the active particles in terms of the time averaged mean squared displacement, revealing a giant diffusivity enhancement for the polymer chain via SPP pooling. Our...
ICFT- An Initial Closed-Loop Flow Test of the Fenton Hill Phase...
ICFT- An Initial Closed-Loop Flow Test of the Fenton Hill Phase II HDR Reservoir Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: ICFT- An Initial...
Testing of a loop heat pipe experimental apparatus under varied acceleration
Kurwitz, Richard Cable
1997-01-01
An experimental apparatus was designed and fabricated to test a Loop Heat Pipe under varied acceleration. The experiment consisted of both flight and ground testing as well as comparisons to a model developed from models ...
Jester-Weinstein, Jack (Jack L.)
2013-01-01
The design process for an experimental platform measuring reaction kinetics in a chemical looping combustion (CLC) process is documented and justified. To enable an experiment designed to characterize the reaction kinetics ...
Rotary bed reactor for chemical-looping combustion with carbon capture
Zhao, Zhenlong
2012-01-01
Chemical-looping combustion (CLC) is a novel and promising technology for power generation with inherent CO2 capture. Currently almost all the research has been focused on developing CLC based inter-connected fluidized bed ...
Joshi, Abhinaya; Lou, Xinsheng; Neuschaefer, Carl; Chaudry, Majid; Quinn, Joseph
2012-07-31
This document provides the results of the project through September 2009. The Phase I project has recently been extended from September 2009 to March 2011. The project extension will begin work on Chemical Looping (CL) Prototype modeling and advanced control design exploration in preparation for a scale-up phase. The results to date include: successful development of dual loop chemical looping process models and dynamic simulation software tools, development and test of several advanced control concepts and applications for Chemical Looping transport control and investigation of several sensor concepts and establishment of two feasible sensor candidates recommended for further prototype development and controls integration. There are three sections in this summary and conclusions. Section 1 presents the project scope and objectives. Section 2 highlights the detailed accomplishments by project task area. Section 3 provides conclusions to date and recommendations for future work.
1/2-BPS Wilson Loops and Vortices in ABJM Model
Lee, Ki-Myeong
2010-01-01
We explore the low-energy dynamics of 1/2-BPS heavy particles coupled to the ABJM model via the Higgsing of M2-branes, with focus on physical understanding of the recently discovered 1/2-BPS Wilson loop operators. The low-energy theory of 1/2-BPS heavy particles turns out to have the U(N|N) supergauge symmetry, which explains the novel structure of the 1/2-BPS Wilson loop operator as a holonomy of a U(N|N) superconnection. We show that the supersymmetric transformation of the Wilson loop operator can be identified as a fermionic supergauge transformation, which leads to their invariance under half of the supersymmetry. We also argue that 1/2-BPS Wilson loop operators appear as 1/2-BPS vortices with vorticity 1/k. Such a vortex can be naturally interpreted as a membrane wrapping the Z_k cycle once, or type IIA fundamental string.
1/2-BPS Wilson Loops and Vortices in ABJM Model
Ki-Myeong Lee; Sungjay Lee
2010-06-29
We explore the low-energy dynamics of 1/2-BPS heavy particles coupled to the ABJM model via the Higgsing of M2-branes, with focus on physical understanding of the recently discovered 1/2-BPS Wilson loop operators. The low-energy theory of 1/2-BPS heavy particles turns out to have the U(N|N) supergauge symmetry, which explains the novel structure of the 1/2-BPS Wilson loop operator as a holonomy of a U(N|N) superconnection. We show that the supersymmetric transformation of the Wilson loop operator can be identified as a fermionic supergauge transformation, which leads to their invariance under half of the supersymmetry. We also argue that 1/2-BPS Wilson loop operators appear as 1/2-BPS vortices with vorticity 1/k. Such a vortex can be naturally interpreted as a membrane wrapping the Z_k cycle once, or type IIA fundamental string.
Exotic twisted equivariant cohomology of loop spaces, twisted Bismut-Chern character and T-duality
Fei Han; Varghese Mathai
2015-01-20
We define exotic twisted $S^1$-equivariant cohomology for the loop space $LZ$ of a smooth manifold $Z$ via the invariant differential forms on $LZ$ with coefficients in the (typically non-flat) holonomy line bundle of a gerbe, with differential an equivariantly flat superconnection. We introduce the twisted Bismut-Chern character form, a loop space refinement of the twisted Chern character form, which represent classes in the completed periodic exotic twisted $S^1$-equivariant cohomology of $LZ$. We establish a localisation theorem for the completed periodic exotic twisted $S^1$-equivariant cohomology for loop spaces and apply it to establish T-duality in a background flux in type II String Theory from a loop space perspective.
Loop formation in graphitic nanoribbon edges using furnace heating or Joule heating
Jia, Xiaoting
Here the authors report the use of either furnace heating or Joule heating to pacify the exposed graphene edges by loop formation in a novel graphitic nanoribbonmaterial, grown by chemical vapor deposition. The edge energy ...
New Developments in Closed Loop Combustion Control Using Flue Gas Analysis
Nelson, R. L.
1981-01-01
New developments in closed loop combustion control are causing radical changes in the way combustion control systems are implemented. The recent availability of in line flue gas analyzers and microprocessor technology are teaming up to produce...
Christine Hartmann; Michael Trott
2015-08-20
We calculate one loop contributions to $\\Gamma(h \\rightarrow \\gamma \\, \\gamma)$ from higher dimensional operators, in the Standard Model Effective Field Theory (SMEFT). Some technical challenges related to determining Electroweak one loop "finite terms" are discussed and overcome. Although we restrict our attention to $\\Gamma(h \\rightarrow \\gamma \\, \\gamma)$, several developments we report have broad implications. Firstly, the running of the vacuum expectation value modifies the $\\log(\\mu)$ dependence of processes in a manner that is not captured in some past SMEFT Renormalization Group (RG) calculations. Secondly, higher dimensional operators can source ghost interactions in $R_\\xi$ gauges due to a modified gauge fixing procedure. Lastly, higher dimensional operators can contribute with pure finite terms at one loop in a manner that is not anticipated in a RG analysis. These results cast recent speculation on the nature of one loop corrections in the SMEFT in an entirely new light.
Galle, G.; Degert, J.; Freysz, E.; Etrillard, C.; Letard, J.-F.; Guillaume, F.
2013-02-11
We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal hysteresis loop of the [Fe(Htrz){sub 2} trz](BF{sub 4}){sub 2}-H{sub 2}O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the hysteresis loop, the photo-induced high spin state remains up to 100 {mu}s and then relaxes. Within the thermal hysteresis loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.
Dickey, James Todd
1993-01-01
An experimental investigation was conducted on a relatively new and unique type of capillary pumped loop (CPL) at various power inputs and adverse tilts in order to verify the operational parameters and measure the performance limits. A...
TRACKING THE LIFE CYCLE OF CONSTRUCTION STEEL: THE DEVELOPMENT OF A RESOURCE LOOP
Liu, Lanfang
2009-12-17
-to-grave, integrate energy and materials in different processes, such as extract, manufacture, transport, install, deconstruct, demolish and dispose of materials. This thesis developed a "resource loop" which represents both the cradle-to-cradle and cradle...
Two-loop self-energy correction in high-Z hydrogen-like ions
V. A. Yerokhin; P. Indelicato; V. M. Shabaev
2003-02-28
A complete evaluation of the two-loop self-energy diagrams to all orders in Z\\alpha is presented for the ground state of H-like ions with Z\\ge 40.
Putting the Scientist in the Loop -Accelerating Scientific Progress with Interactive
Brostow, Gabriel
. The standard machine learning pipeline consists of data label- ing, feature extraction, trainingPutting the Scientist in the Loop - Accelerating Scientific Progress with Interactive Machine Science, University of Waterloo 3Center for Biodiversity and Environment Research, University College
Dynamics of end to end loop formation for an isolated chain in viscoelastic fluid
Rajarshi Chakrabarti
2012-04-04
We theoretically investigate the looping dynamics of a linear polymer immersed in a viscoelastic fluid. The dynamics of the chain is governed by a Rouse model with a fractional memory kernel recently proposed by Weber et al. (S. C. Weber, J. A. Theriot, and A. J. Spakowitz, Phys. Rev. E 82, 011913 (2010)). Using the Wilemski-Fixman (G. Wilemski and M. Fixman, J. Chem. Phys. 60, 866 (1974)) formalism we calculate the looping time for a chain in a viscoelastic fluid where the mean square displacement of the center of mass of the chain scales as t^(1/2). We observe that the looping time is faster for the chain in viscoelastic fluid than for a Rouse chain in Newtonian fluid up to a chain length and above this chain length the trend is reversed. Also no scaling of the looping time with the length of the chain seems to exist for the chain in viscoelastic fluid.
The picture of the Bianchi I model via gauge fixing in Loop Quantum Gravity
Francesco Cianfrani; Andrea Marchini; Giovanni Montani
2012-01-12
The implications of the SU(2) gauge fixing associated with the choice of invariant triads in Loop Quantum Cosmology are discussed for a Bianchi I model. In particular, via the analysis of Dirac brackets, it is outlined how the holonomy-flux algebra coincides with the one of Loop Quantum Gravity if paths are parallel to fiducial vectors only. This way the quantization procedure for the Bianchi I model is performed by applying the techniques developed in Loop Quantum Gravity but restricting the admissible paths. Furthermore, the local character retained by the reduced variables provides a relic diffeomorphisms constraint, whose imposition implies homogeneity on a quantum level. The resulting picture for the fundamental spatial manifold is that of a cubical knot with attached SU(2) irreducible representations. The discretization of geometric operators is outlined and a new perspective for the super-Hamiltonian regularization in Loop Quantum Cosmology is proposed.
Simulations of Gyrosynchrotron Microwave Emission from an Oscillating 3D Magnetic Loop
Kuznetsov, Alexey; Reznikova, Veronika
2015-01-01
Radio observations of solar flares often reveal various periodic or quasi-periodic oscillations. Most likely, these oscillations are caused by magnetohydrodynamic (MHD) oscillations of flaring loops which modulate the emission. Interpretation of the observations requires comparing them with simulations. We simulate the gyrosynchrotron radio emission from a semi-circular (toroidal-shaped) magnetic loop containing sausage-mode MHD oscillations. The aim is to detect the observable signatures specific to the considered MHD mode and to study their dependence on the various source parameters. The MHD waves are simulated using a linear three-dimensional model of a magnetized plasma cylinder; both standing and propagating waves are considered. The curved loop is formed by replicating the MHD solutions along the plasma cylinder and bending the cylinder; this model allows us to study the effect of varying the viewing angle along the loop. The radio emission is simulated using a three-dimensional model and its spatial a...
Lessons for Loop Quantum Gravity from Parametrised Field Theory
Thomas Thiemann
2010-10-12
In a series of seminal papers, Laddha and Varadarajan have developed in depth the quantisation of Parametrised Field Theory (PFT) in the kind of discontinuous representations that are employed in Loop Quantum Gravity (LQG). In one spatial dimension (circle) PFT is very similar to the closed bosonic string and the constraint algebra is isomorphic to two mutually commuting Witt algebras. Its quantisation is therefore straightforward in LQG like representations which by design lead to non anomalous, unitary, albeit discontinuous representations of the spatial diffeomorphism group. In particular, the complete set of (distributional) solutions to the quantum constraints, a preferred and complete algebra of Dirac observables and the associated physical inner product has been constructed. On the other hand, the two copies of Witt algebras are classically isomorphic to the Dirac or hypersurface deformation algebra of General Relativity (although without structure functions). The question we address in this paper, also raised by Laddha and Varadarajan in their paper, is whether we can quantise the Dirac algebra in such a way that its space of distributional solutions coincides with the one just described. This potentially teaches us something about LQG where a classically equivalent formulation of the Dirac algebra in terms of spatial diffeomorphism Lie algebras is not at our disposal. We find that, in order to achieve this, the Hamiltonian constraint has to be quantised by methods that extend those previously considered. The amount of quantisation ambiguities is somewhat reduced but not eliminated. We also show that the algebra of Hamiltonian constraints closes in a precise sense, with soft anomalies, that is, anomalies that do not cause inconsistencies. We elaborate on the relevance of these findings for full LQG.
Molten Salt Test Loop (MSTL) system customer interface document.
Gill, David Dennis; Kolb, William J.; Briggs, Ronald D.
2013-09-01
The National Solar Thermal Test Facility at Sandia National Laboratories has a unique test capability called the Molten Salt Test Loop (MSTL) system. MSTL is a test capability that allows customers and researchers to test components in flowing, molten nitrate salt. The components tested can range from materials samples, to individual components such as flex hoses, ball joints, and valves, up to full solar collecting systems such as central receiver panels, parabolic troughs, or linear Fresnel systems. MSTL provides realistic conditions similar to a portion of a concentrating solar power facility. The facility currently uses 60/40 nitrate %E2%80%9Csolar salt%E2%80%9D and can circulate the salt at pressure up to 40 bar (600psi), temperature to 585%C2%B0C, and flow rate of 44-50kg/s(400-600GPM) depending on temperature. The purpose of this document is to provide a basis for customers to evaluate the applicability to their testing needs, and to provide an outline of expectations for conducting testing on MSTL. The document can serve as the basis for testing agreements including Work for Others (WFO) and Cooperative Research and Development Agreements (CRADA). While this document provides the basis for these agreements and describes some of the requirements for testing using MSTL and on the site at Sandia, the document is not sufficient by itself as a test agreement. The document, however, does provide customers with a uniform set of information to begin the test planning process.
An investigation of synthetic fuel production via chemical looping
Frank Zeman; Marco Castaldi
2008-04-15
Producing liquid hydrocarbon fuels with a reduced greenhouse gas emissions profile would ease the transition to a carbon-neutral energy sector with the transportation industry being the immediate beneficiary followed by the power industry. Revolutionary solutions in transportation, such as electricity and hydrogen, depend on the deployment of carbon capture and storage technologies and/or renewable energy systems. Additionally, high oil prices may increase the development of unconventional sources, such as tar sands, that have a higher emissions profile. One process that is gaining interest is a system for producing reduced carbon fuels though chemical looping technologies. An investigation of the implications of such a process using methane and carbon dioxide that is reformed to yield methanol has been done. An important aspect of the investigation is the use of off-the-shelf technologies to achieve the results. The ability of the process to yield reduced emissions fuels depends on the source for the feed and process heat. For the range of conditions considered, the emissions profile of methanol produced in this method varies from 0.475 to 1.645 moles carbon dioxide per mole methanol. The thermal load can be provided by methane, coal or carbon neutral (biogas). The upper bound can be lowered to 0.750 by applying CCS and/or using nonfossil heat sources for the reforming. The process provides an initial pathway to incorporate CO{sub 2} into fuels independent of electrolytic hydrogen or developments in other sectors of the economy. 22 refs., 1 fig., 3 tabs.
The Tetrahedron algebra, the Onsager algebra, and the $\\mathfrak{sl}_2$ loop algebra
Brian Hartwig; Paul Terwilliger
2005-11-02
Let $K$ denote a field with characteristic 0 and let $T$ denote an indeterminate. We give a presentation for the three-point loop algebra $\\mathfrak{sl}_2 \\otimes K\\lbrack T, T^{-1},(T-1)^{-1}\\rbrack$ via generators and relations. This presentation displays $S_4$-symmetry. Using this presentation we obtain a decomposition of the above loop algebra into a direct sum of three subalgebras, each of which is isomorphic to the Onsager algebra.
Finite-dimensional irreducible modules for the three-point $\\mathfrak{sl}_2$ loop algebra
Ito, Tatsuro
2007-01-01
Recently Brian Hartwig and the second author found a presentation for the three-point $sl_2$ loop algebra by generators and relations. To obtain this presentation they defined a Lie algebra $\\boxtimes$ by generators and relations, and displayed an isomorphism from $\\boxtimes$ to the three-point $sl_2$ loop algebra. In this paper we describe the finite-dimensional irreducible $\\boxtimes$-modules from multiple points of view.
Poisoned Feedback: The Impact of Malicious Users in Closed-Loop Multiuser MIMO Systems
Mukherjee, Amitav
2010-01-01
Accurate channel state information (CSI) at the transmitter is critical for maximizing spectral efficiency on the downlink of multi-antenna networks. In this work we analyze a novel form of physical layer attacks on such closed-loop wireless networks. Specifically, this paper considers the impact of deliberately inaccurate feedback by malicious users in a multiuser multicast system. Numerical results demonstrate the significant degradation in performance of closed-loop transmission schemes due to intentional feedback of false CSI by adversarial users.
Modelling solar low-lying cool loops with optically thick radiative losses
Sasso, C; Spadaro, D
2015-01-01
We investigate the increase of the DEM (differential emission measure) towards the chromosphere due to small and cool magnetic loops (height $\\lesssim8$~Mm, $T\\lesssim10^5$~K). In a previous paper we analysed the conditions of existence and stability of these loops through hydrodynamic simulations, focusing on their dependence on the details of the optically thin radiative loss function used. In this paper, we extend those hydrodynamic simulations to verify if this class of loops exists and it is stable when using an optically thick radiative loss function. We study two cases: constant background heating and a heating depending on the density. The contribution to the transition region EUV output of these loops is also calculated and presented. We find that stable, quasi-static cool loops can be obtained by using an optically thick radiative loss function and a background heating depending on the density. The DEMs of these loops, however, fail to reproduce the observed DEM for temperatures between $4.6<\\log...
Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate
Mittereder, N.; Poerschke, A.
2013-11-01
This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.
Observational Tests of Damping by Resonant Absorption in Coronal Loop Oscillations
Markus J. Aschwanden; Richard W. Nightingale; Jesse Andries; Marcel Goossens; Tom Van Doorsselaere
2003-09-17
One of the proposed damping mechanisms of coronal (transverse) loop oscillations in the kink-mode is resonant absorption as a result of the Alfven speed variation at the outer boundary of coronal loops. Analytical expressions for the period and damping time exist for loop models with thin non-uniform boundaries. Here we measure the thickness of the non-uniform layer in oscillating loops for 11 events, by forward-fitting of the cross-sectional density profile and line-of-sight integration to the cross-sectional fluxes observed with TRACE 171 A. This way we model the internal and external electron density of the coronal plasma in oscillating loops. This allows us to test the theoretically predicted damping rates for thin boundaries as function of the density ratio. We find that the density ratio predicted by the damping time is higher than the density ratio estimated from the background fluxes. The lower densities modeled from the background fluxes are likely to be a consequence of the neglected hotter plasma that is not detected with the TRACE 171 A filter. Taking these correction into account, resonant absorption predicts damping times of kink-mode oscillations that are commensurable with the observed ones and provides a new diagnostic of the density contrast of oscillating loops.
The three-loop cusp anomalous dimension in QCD and its supersymmetric extensions
Andrey Grozin; Johannes M. Henn; Gregory P. Korchemsky; Peter Marquard
2015-11-27
We present the details of the analytic calculation of the three-loop angle-dependent cusp anomalous dimension in QCD and its supersymmetric extensions, including the maximally supersymmetric $\\mathcal{N}=4$ super Yang-Mills theory. The three-loop result in the latter theory is new and confirms a conjecture made in our previous paper. We study various physical limits of the cusp anomalous dimension and discuss its relation to the quark-antiquark potential including the effects of broken conformal symmetry in QCD. We find that the cusp anomalous dimension viewed as a function of the cusp angle and the new effective coupling given by light-like cusp anomalous dimension reveals a remarkable universality property -- it takes the same form in QCD and its supersymmetric extensions, to three loops at least. We exploit this universality property and make use of the known result for the three-loop quark-antiquark potential to predict the special class of nonplanar corrections to the cusp anomalous dimensions at four loops. Finally, we also discuss in detail the computation of all necessary Wilson line integrals up to three loops using the method of leading singularities and differential equations.
Canonical Transformations and Loop Formulation of SU(N) Lattice Gauge Theories
Mathur, Manu
2015-01-01
We construct canonical transformations to reformulate SU(N) Kogut-Susskind lattice gauge theory in terms of a set of fundamental loop & string flux operators along with their canonically conjugate loop & string electric fields. We show that as a consequence of SU(N) Gauss laws all SU(N) string degrees of freedom become cyclic and decouple from the physical Hilbert space ${\\cal H}^p$. The canonical relations between the initial SU(N) link operators and the final SU(N) loop & string operators over the entire lattice are worked out in a self consistent manner. The Kogut-Susskind Hamiltonian rewritten in terms of the fundamental physical loop operators has global SU(N) invariance. There are no gauge fields. We further show that the $(1/g^2)$ magnetic field terms on plaquettes create and annihilate the fundamental plaquette loop fluxes while the $(g^2)$ electric field terms describe all their interactions. In the weak coupling ($g^2 \\rightarrow 0$) continuum limit the SU(N) loop dynamics is described b...
Probing Wilson loops in ${\\cal N}=4$ Chern-Simons-matter theories at weak coupling
Griguolo, Luca; Mauri, Andrea; Penati, Silvia; Seminara, Domenico
2015-01-01
For three-dimensional ${\\cal N}=4$ super Chern-Simons-matter theories associated to necklace quivers $U(N_0) \\times U(N_1) \\times \\cdots U(N_{2r-1}) $, we study at quantum level the two kinds of 1/2 BPS Wilson loop operators recently introduced in arXiv:1506.07614. We perform a two-loop evaluation and find the same result for the two kinds of operators, so moving to higher loops a possible quantum uplift of the classical degeneracy. We also compute the 1/4 BPS bosonic Wilson loop and discuss the quantum version of the cohomological equivalence between fermionic and bosonic Wilson loops. We compare the perturbative result with the Matrix Model prediction and find perfect matching, after identification and remotion of a suitable framing factor. Finally, we discuss the potential appearance of three-loop contributions that might break the classical degeneracy and briefly analyse possible implications on the BPS nature of these operators.
McFarlane, Joanna; Bell, Jason R; Felde, David K; Joseph III, Robert Anthony; Qualls, A L; Weaver, Samuel P
2014-01-01
Polyaromatic hydrocarbon thermal fluids showing thermally stability to 600 C have been tested for solar thermal-power applications. Although static thermal tests showed promising results for 1-phenylnaphthalene, loop testing at temperatures to 450 C indicated that the fluid isomerized and degraded at a slow rate. In a loop with a temperature high enough to drive the isomerization, the higher melting point byproducts tended to condense onto cooler surfaces. So, as experienced in loop operation, eventually the internal channels of cooler components in trough solar electric generating systems, such as the waste heat rejection exchanger, may become coated or clogged affecting loop performance. Thus, pure 1-phenylnaphthalene, without addition of stabilizers, does not appear to be a fluid that would have a sufficiently long lifetime (years to decades) to be used in a loop at the temperatures greater than 500 C. The performance of a concentrating solar loop using high temperature fluids was modeled based on the National Renewable Laboratory Solar Advisory Model. It was determined that a solar-to-electricity efficiency of up to 30% and a capacity factor of near 60% could be achieved using a high efficiency collector and 12 h thermal energy storage.
arXiv:0709.3636v1[hep-ex]23Sep2007 Detecting Neutrino Magnetic Moments with Conducting Loops
arXiv:0709.3636v1[hep-ex]23Sep2007 Detecting Neutrino Magnetic Moments with Conducting Loops Aram the possibility of detecting the magnetic moment using a conducting loop. According to Faraday's Law of Induction, a magnetic dipole passing through a conducting loop induces an electromotive force, or EMF, in the loop. We
Relationship of edge localized mode burst times with divertor flux loop signal phase in JET
Chapman, S. C., E-mail: S.C.Chapman@warwick.ac.uk [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry (United Kingdom); Max Planck Institute for the Physics of Complex Systems, Dresden (Germany); Dendy, R. O. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry (United Kingdom); Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon, Oxfordshire (United Kingdom); Todd, T. N.; Webster, A. J.; Morris, J. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon, Oxfordshire (United Kingdom); Watkins, N. W. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry (United Kingdom); Max Planck Institute for the Physics of Complex Systems, Dresden (Germany); Centre for the Analysis of Time Series, London School of Economics, London (United Kingdom); Department of Engineering and Innovation, Open University, Milton Keynes (United Kingdom); Calderon, F. A. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon, Oxfordshire (United Kingdom)
2014-06-15
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM.
Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics
Lowe, K.T.
2005-10-07
The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.
Conceptual Design of Forced Convection Molten Salt Heat Transfer Testing Loop
Manohar S. Sohal; Piyush Sabharwall; Pattrick Calderoni; Alan K. Wertsching; S. Brandon Grover
2010-09-01
This report develops a proposal to design and construct a forced convection test loop. A detailed test plan will then be conducted to obtain data on heat transfer, thermodynamic, and corrosion characteristics of the molten salts and fluid-solid interaction. In particular, this report outlines an experimental research and development test plan. The most important initial requirement for heat transfer test of molten salt systems is the establishment of reference coolant materials to use in the experiments. An earlier report produced within the same project highlighted how thermophysical properties of the materials that directly impact the heat transfer behavior are strongly correlated to the composition and impurities concentration of the melt. It is therefore essential to establish laboratory techniques that can measure the melt composition, and to develop purification methods that would allow the production of large quantities of coolant with the desired purity. A companion report describes the options available to reach such objectives. In particular, that report outlines an experimental research and development test plan that would include following steps: •Molten Salts: The candidate molten salts for investigation will be selected. •Materials of Construction: Materials of construction for the test loop, heat exchangers, and fluid-solid corrosion tests in the test loop will also be selected. •Scaling Analysis: Scaling analysis to design the test loop will be performed. •Test Plan: A comprehensive test plan to include all the tests that are being planned in the short and long term time frame will be developed. •Design the Test Loop: The forced convection test loop will be designed including extensive mechanical design, instrument selection, data acquisition system, safety requirements, and related precautionary measures. •Fabricate the Test Loop. •Perform the Tests. •Uncertainty Analysis: As a part of the data collection, uncertainty analysis will be performed to develop probability of confidence in what is measured in the test loop. Overall, the testing loop will allow development of needed heat transfer related thermophysical parameters for all the salts, validate existing correlations, validate measuring instruments under harsh environment, and have extensive corrosion testing of materials of construction.
Gontikakis, C.; Efthymiopoulos, C.; Georgoulis, M. K.; Patsourakos, S.; Anastasiadis, A.
2013-07-10
We model nanoflare heating of extrapolated active-region coronal loops via the acceleration of electrons and protons in Harris-type current sheets. The kinetic energy of the accelerated particles is estimated using semi-analytical and test-particle-tracing approaches. Vector magnetograms and photospheric Doppler velocity maps of NOAA active region 09114, recorded by the Imaging Vector Magnetograph, were used for this analysis. A current-free field extrapolation of the active-region corona was first constructed. The corresponding Poynting fluxes at the footpoints of 5000 extrapolated coronal loops were then calculated. Assuming that reconnecting current sheets develop along these loops, we utilized previous results to estimate the kinetic energy gain of the accelerated particles. We related this energy to nanoflare heating and macroscopic loop characteristics. Kinetic energies of 0.1-8 keV (for electrons) and 0.3-470 keV (for protons) were found to cause heating rates ranging from 10{sup -6} to 1 erg s{sup -1} cm{sup -3}. Hydrodynamic simulations show that such heating rates can sustain plasma in coronal conditions inside the loops and generate plasma thermal distributions that are consistent with active-region observations. We concluded the analysis by computing the form of X-ray spectra generated by the accelerated electrons using the thick-target approach. These spectra were found to be in agreement with observed X-ray spectra, thus supporting the plausibility of our nanoflare-heating scenario.
ENTHALPY-BASED THERMAL EVOLUTION OF LOOPS. II. IMPROVEMENTS TO THE MODEL
Cargill, P. J.; Bradshaw, S. J.; Klimchuk, J. A.
2012-06-20
This paper develops the zero-dimensional (0D) hydrodynamic coronal loop model 'Enthalpy-based Thermal Evolution of Loops' (EBTEL) proposed by Klimchuk et al., which studies the plasma response to evolving coronal heating, especially impulsive heating events. The basis of EBTEL is the modeling of mass exchange between the corona and transition region (TR) and chromosphere in response to heating variations, with the key parameter being the ratio of the TR to coronal radiation. We develop new models for this parameter that now include gravitational stratification and a physically motivated approach to radiative cooling. A number of examples are presented, including nanoflares in short and long loops, and a small flare. The new features in EBTEL are important for accurate tracking of, in particular, the density. The 0D results are compared to a 1D hydro code (Hydrad) with generally good agreement. EBTEL is suitable for general use as a tool for (1) quick-look results of loop evolution in response to a given heating function, (2) extensive parameter surveys, and (3) situations where the modeling of hundreds or thousands of elemental loops is needed. A single run takes a few seconds on a contemporary laptop.
Arens, Edward; Brown, Karl
2012-01-01
Prevent Good Building Energy Performance—Integrated Prevent Good Building Energy Performance—Integrated Loops Prevent Good Building Energy Performance—Integrated
Effect of the Gribov horizon on the Polyakov loop and vice versa
Canfora, F E; Justo, I F; Pais, P; Rosa, L; Vercauteren, D
2015-01-01
We consider finite temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanzig...
One-loop calculations in quantum field theory: from Feynman diagrams to unitarity cuts
Ellis, R. Keith [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Kunszt, Zoltan [Institute for Theoretical Physics (Switzerland); Melnikov, Kirill [Johns Hopkins Univ., Baltimore, MD (United States); Zanderighi, Giulia [Rudolf Peierls Centre for Theoretical Physics (United Kingdom)
2012-09-01
The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of one-loop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.
Multilevel Deconstruction of the In Vivo Behavior of Looped DNA-Protein Complexes
Leonor Saiz; Jose M. G. Vilar
2007-04-18
Protein-DNA complexes with loops play a fundamental role in a wide variety of cellular processes, ranging from the regulation of DNA transcription to telomere maintenance. As ubiquitous as they are, their precise in vivo properties and their integration into the cellular function still remain largely unexplored. Here, we present a multilevel approach that efficiently connects in both directions molecular properties with cell physiology and use it to characterize the molecular properties of the looped DNA-lac repressor complex while functioning in vivo. The properties we uncover include the presence of two representative conformations of the complex, the stabilization of one conformation by DNA architectural proteins, and precise values of the underlying twisting elastic constants and bending free energies. Incorporation of all this molecular information into gene-regulation models reveals an unprecedented versatility of looped DNA-protein complexes at shaping the properties of gene expression.
Modelling of Reflective Propagating Slow-mode Wave in a Flaring Loop
Fang, X; Van Doorsselaere, T; Keppens, R; Xia, C
2015-01-01
Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association with persistent coronal upflows, making this interpretation debatable. We perform a 2.5D magnetohydrodynamic simulation to imitate the chromospheric evaporation and the following reflected patterns in a flare loop. Our model encompasses the corona, transition region, and chromosphere. We demonstrate that the quasi periodic propagating intensity variations captured by the synthesized \\textit{Solar Dynamics Observatory}/Atmospheric Imaging Assembly (AIA) 131, 94~\\AA~emission images match the previous observations well. With particle tracers in the simulation, we confirm that these quasi periodic propagating intensity variations consist of reflected slow mode waves and mass flows with an average speed of 310 km/s in an 80 Mm length loop with an average temperatu...
Ultra-high-frequency piecewise-linear chaos using delayed feedback loops
Seth D. Cohen; Damien Rontani; Daniel J. Gauthier
2012-08-14
We report on an ultra-high-frequency (> 1 GHz), piecewise-linear chaotic system designed from low-cost, commercially available electronic components. The system is composed of two electronic time-delayed feedback loops: A primary analog loop with a variable gain that produces multi-mode oscillations centered around 2 GHz and a secondary loop that switches the variable gain between two different values by means of a digital-like signal. We demonstrate experimentally and numerically that such an approach allows for the simultaneous generation of analog and digital chaos, where the digital chaos can be used to partition the system's attractor, forming the foundation for a symbolic dynamics with potential applications in noise-resilient communications and radar.
Sensitivity of the blue loops of intermediate-mass stars to nuclear reactions
Halabi, Ghina M.; El Eid, Mounib
2012-11-20
We investigate the effects of a modification of the {sup 14}N(p,{gamma}){sup 15}O reaction rate, as suggested by recent evaluations, on the formation and extension of the blue loops encountered during the evolution of the stars in the mass range 5M{sub Circled-Dot-Operator} to 12M{sub Circled-Dot-Operator }. We show that the blue loops of stars in the mass range 5M{sub Circled-Dot-Operator} to 8M{sub Circled-Dot-Operator }, that is the range of super ABG stars, are severely affected by a modification of the important {sup 14}N(p,{gamma}){sup 15}O reaction rate. We also show that the blue loops can be restored if envelope overshooting is included, which is necessary to explain the observations of the Cepheid stars.
Solid oxide fuel cell power plant with an anode recycle loop turbocharger
Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.
2015-07-14
An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).
Numerical Study of a Propagating Non-Thermal Microwave Feature in a Solar Flare Loop
T. Minoshima; T. Yokoyama
2008-06-24
We analytically and numerically study the motion of electrons along a magnetic loop, to compare with the observation of the propagating feature of the non-thermal microwave source in the 1999 August 28 solar flare reported by Yokoyama et al. (2002). We model the electron motion with the Fokker-Planck equation and calculate the spatial distribution of the gyrosynchrotron radiation. We find that the microwave propagating feature does not correspond to the motion of electrons with a specific initial pitch angle. This apparent propagating feature is a consequence of the motion of an ensemble of electrons with different initial pitch angles, which have different time and position to produce strong radiation in the loop. We conclude that the non-thermal electrons in the 1999 August 28 flare were isotropically accelerated and then are injected into the loop.
The Lattice Free Energy of QCD with Clover Fermions, up to Three-Loops
A. Athenodorou; H. Panagopoulos; A. Tsapalis
2007-10-20
We calculate the perturbative value of the free energy in Lattice QCD, up to three loops. Our calculation is performed using Wilson gluons and the Sheikholeslami - Wolhert (clover) improved action for fermions. The free energy is directly related to the average plaquette. To carry out the calculation, we compute all relevant Feynman diagrams up to 3 loops, using a set of automated procedures in Mathematica; numerical evaluation of the resulting loop integrals is performed on finite lattice, with subsequent extrapolation to infinite size. The results are presented as a function of the fermion mass m, for any SU(N_c) gauge group, and for an arbitrary number of fermion flavors. In order to enable independent comparisons, we also provide the results on a per diagram basis, for a specific mass value.
A Proposal for a Standard Interface Between Monte Carlo Tools And One-Loop Programs
Binoth, T.; Boudjema, F.; Dissertori, G.; Lazopoulos, A.; Denner, A.; Dittmaier, S.; Frederix, R.; Greiner, N.; Hoeche, Stefan; Giele, W.; Skands, P.; Winter, J.; Gleisberg, T.; Archibald, J.; Heinrich, G.; Krauss, F.; Maitre, D.; Huber, M.; Huston, J.; Kauer, N.; Maltoni, F.; /Louvain U., CP3 /Milan Bicocca U. /INFN, Turin /Turin U. /Granada U., Theor. Phys. Astrophys. /CERN /NIKHEF, Amsterdam /Heidelberg U. /Oxford U., Theor. Phys.
2011-11-11
Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarises the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV Colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.
String loops in the field of braneworld spherically symmetric black holes and naked singularities
Stuchlík, Z.; Kološ, M. E-mail: martin.kolos@fpf.slu.cz
2012-10-01
We study motion of current-carrying string loops in the field of braneworld spherically symmetric black holes and naked singularities. The spacetime is described by the Reissner-Nordström geometry with tidal charge b reflecting the non-local tidal effects coming from the external dimension; both positive and negative values of the spacetime parameter b are considered. We restrict attention to the axisymmetric motion of string loops when the motion can be fully governed by an appropriately defined effective potential related to the energy and angular momentum of the string loops. In dependence on these two constants of the motion, the string loops can be captured, trapped, or can escape to infinity. In close vicinity of stable equilibrium points at the centre of trapped states the motion is regular. We describe how it is transformed to chaotic motion with growing energy of the string loop. In the field of naked singularities the trapped states located off the equatorial plane of the system exist and trajectories unable to cross the equatorial plane occur, contrary to the trajectories in the field of black holes where crossing the equatorial plane is always admitted. We concentrate our attention to the so called transmutation effect when the string loops are accelerated in the deep gravitational field near the black hole or naked singularity by transforming the oscillatory energy to the energy of the transitional motion. We demonstrate that the influence of the tidal charge can be substantial especially in the naked singularity spacetimes with b > 1 where the acceleration to ultrarelativistic velocities with Lorentz factor ? ? 100 can be reached, being more than one order higher in comparison with those obtained in the black hole spacetimes.
Heating mechanisms for intermittent loops in active region cores from AIA/SDO EUV observations
Cadavid, A. C.; Lawrence, J. K.; Christian, D. J.; Jess, D. B.; Nigro, G.
2014-11-01
We investigate intensity variations and energy deposition in five coronal loops in active region cores. These were selected for their strong variability in the AIA/SDO 94 Å intensity channel. We isolate the hot Fe XVIII and Fe XXI components of the 94 Å and 131 Å by modeling and subtracting the 'warm' contributions to the emission. HMI/SDO data allow us to focus on 'inter-moss' regions in the loops. The detailed evolution of the inter-moss intensity time series reveals loops that are impulsively heated in a mode compatible with a nanoflare storm, with a spike in the hot 131 Å signals leading and the other five EUV emission channels following in progressive cooling order. A sharp increase in electron temperature tends to follow closely after the hot 131 Å signal confirming the impulsive nature of the process. A cooler process of growing emission measure follows more slowly. The Fourier power spectra of the hot 131 Å signals, when averaged over the five loops, present three scaling regimes with break frequencies near 0.1 min{sup –1} and 0.7 min{sup –1}. The low frequency regime corresponds to 1/f noise; the intermediate indicates a persistent scaling process and the high frequencies show white noise. Very similar results are found for the energy dissipation in a 2D 'hybrid' shell model of loop magneto-turbulence, based on reduced magnetohydrodynamics, that is compatible with nanoflare statistics. We suggest that such turbulent dissipation is the energy source for our loops.
Speed of sound in quark gluon plasma with one loop correction in mean field potential
Singh, S Somorendro
2015-01-01
We study thermodynamic properties and speed of sound in a free en- ergy evolution of quark-gluon plasma (QGP) with one loop correction factor in the mean-field potential. The values of the thermodynamic prop- erties like pressure, entropy and specific heat are calculated for a range of temperatures. The results agree with the recent lattice results. The speed of sound is found to be C2 s = 0.3 independent of parameters used in the loop correction which matches almost with lattice calculations.
Hardware In The Loop Simulator in UAV Rapid Development Life Cycle
Adiprawita, Widyawardana; Semibiring, Jaka
2008-01-01
Field trial is very critical and high risk in autonomous UAV development life cycle. Hardware in the loop (HIL) simulation is a computer simulation that has the ability to simulate UAV flight characteristic, sensor modeling and actuator modeling while communicating in real time with the UAV autopilot hardware. HIL simulation can be used to test the UAV autopilot hardware reliability, test the closed loop performance of the overall system and tuning the control parameter. By rigorous testing in the HIL simulator, the risk in the field trial can be minimized.
Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant
Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN
2006-02-07
A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.
Automation of One-Loop Calculations with GoSam: Present Status and Future Outlook
Gavin Cullen; Nicolas Greiner; Gudrun Heinrich; Gionata Luisoni; Pierpaolo Mastrolia; Giovanni Ossola; Thomas Reiter; Francesco Tramontano
2011-11-14
In this presentation, we describe the GoSam (Golem/Samurai) framework for the automated computation of multi-particle scattering amplitudes at the one-loop level. The amplitudes are generated analytically in terms of Feynman diagrams, and can be evaluated using either D-dimensional integrand reduction or tensor decomposition. GoSam can be used to compute one-loop corrections to Standard Model (QCD and EW) processes, and it is ready to link generic model files for theories Beyond SM. We show the main features of GoSam through its application to several examples of different complexity.
Intermediate Heat Transfer Loop Study for High Temperature Gas-Cooled Reactor
C. H. Oh; C. Davis; S. Sherman
2008-08-01
A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed to perform thermal-hydraulic and cycleefficiency evaluations of the different configurations and coolants. The thermal-hydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. This paper also includes a portion of stress analyses performed on pipe configurations.
Speed of sound in quark gluon plasma with one loop correction in mean field potential
S. Somorendro Singh; R. Ramanathan
2015-05-14
We study thermodynamic properties and speed of sound in a free en- ergy evolution of quark-gluon plasma (QGP) with one loop correction factor in the mean-field potential. The values of the thermodynamic prop- erties like pressure, entropy and specific heat are calculated for a range of temperatures. The results agree with the recent lattice results. The speed of sound is found to be C2 s = 0.3 independent of parameters used in the loop correction which matches almost with lattice calculations.
Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal-term behavior of ground loop heat exchangers (GLHE) is critical to the design and energy analysis of ground in the tube to guarantee a low convective heat transfer resistance. However, for some antifreeze types
Vallino, Joseph J.
Microbial Grazing Lab The microbial loop is responsible for the cycling of nutrients as well) and nanoplankton (eg. Flagellates 2-20 m) grazing of picoplankton (eg. Bacteria 0.2-2 m) provide the flow of energy and mass to higher trophic levels via the postulated microbial loop. In order to determine the grazing
source heat pump (GSHP) systems. Thermal load profiles vary significantly from building to buildingModeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal-term behavior of ground loop heat exchangers (GLHE) is critical to the design and energy analysis of ground
A Pipelined Execution of Tiled Nested Loops onto a Cluster of PCs using PCI-SCI NICs
Koziris, Nectarios G.
A Pipelined Execution of Tiled Nested Loops onto a Cluster of PCs using PCI-SCI NICs Aristidis of executing tiled nested loop based programs onto clus- ters of PCs using PCI-SCI Network Interface Cards zero-copy mes- saging through pinned-down physical memory regions for DMA (PCI exported segments to SCI
Scharnhorst, Klaus
lattice with a bending rigidity 1/2. The present paper applies two approximate analytical methods precisely which also can be understood as a self-avoiding loop model on the square lattice with a bending31 . Somewhat less attention has been paid so far to the self-avoiding loop model with a variable bending
Meirovitch, Hagai
Absolute Free Energy and Entropy of a Mobile Loop of the Enzyme Acetylcholinesterase Mihail dissociation measurements suggest that the free-energy (F) penalty for the loop displacement is F ) Ffree contribution of water to the total free energy. Namely, for water densities close to the experimental value
Steinbock, Oliver
Stationary Vortex Loops Induced by Filament Interaction and Local Pinning in a Chemical Reaction rings are three-dimensional excitation waves rotating around one-dimensional filament loops but curved filaments. The absence of filament motion can be explained by repulsive interaction
Zhang, Jun; Yang, Shuhong; Li, Ting; Zhang, Yuzong; Li, Leping [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Jiang, Chaowei, E-mail: zjun@nao.cas.cn, E-mail: shuhongyang@nao.cas.cn, E-mail: liting@nao.cas.cn, E-mail: yuzong@nao.cas.cn, E-mail: lepingli@nao.cas.cn, E-mail: cwjiang@spaceweather.ac.cn [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)
2013-10-10
We employ Solar Dynamics Observatory observations and select three well-observed events including two flares and one extreme-ultraviolet (EUV) brightening. During the three events, the EUV loops clearly changed. One event was related to a major solar flare that took place on 2012 July 12 in active region NOAA AR 11520. 'Open' EUV loops rooted in a facula of the AR deflected to the post-flare loops and then merged with them while the flare ribbon approached the facula. Meanwhile, 'open' EUV loops rooted in a pore disappeared from top to bottom as the flare ribbon swept over the pore. The loop evolution was similar in the low-temperature channels (e.g., 171 Å) and the high-temperature channels (e.g., 94 Å). The coronal magnetic fields extrapolated from the photospheric vector magnetograms also show that the fields apparently 'open' prior to the flare become closed after it. The other two events were associated with a B1.1 flare on 2010 May 24 and an EUV brightening on 2013 January 03, respectively. During both of these two events, some 'open' loops either disappeared or darkened before the formation of new closed loops. We suggest that the observations reproduce the picture predicted by the standard magnetic reconnection model: 'open' magnetic fields become closed due to reconnection, manifesting as a transformation from 'open' EUV loops to closed post-flare ones.
Thirumalai, Devarajan
,§ and D. Thirumalai*,¶,# Biophysics Program, Institute for Physical Science and Technology, UniKinetics of Loop Formation in Polymer Chains Ngo Minh Toan,¶, Greg Morrison,¶,£ Changbong Hyeon, 2007 We investigate the kinetics of loop formation in ideal flexible polymer chains (the Rouse model
Harmonic tori in symmetric spaces and commuting Hamiltonian systems on loop algebras
Harmonic tori in symmetric spaces and commuting Hamiltonian systems on loop algebras F. E. Burstall, D. Ferus, F. Pedit, and U. Pinkall Introduction Background The study of harmonic maps of compact and Physics: For example, minimal surfaces are (conformal) harmonic maps while constant mean curvature
On the Optimality of Allen and Kennedy's Algorithm for Parallelism Extraction in Nested Loops
Vivien, Frédéric
On the Optimality of Allen and Kennedy's Algorithm for Parallelism Extraction in Nested Loops Alain is that Allen and Kennedy's algorithm is optimal when dependences are approximated by dependence levels and Kennedy's algorithm, as long as dependence level is the only information available. 1 Introduction Many
On the optimality of Allen and Kennedy's algorithm for parallelism extraction in nested loops
Vivien, Frédéric
On the optimality of Allen and Kennedy's algorithm for parallelism extraction in nested loops Alain. The result of this paper is that Allen and Kennedy's algorithm is optimal when dependences are approximated found by Allen and Kennedy's algorithm, as long as dependence level is the only information available
FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING
Ollivier, FranÃ§ois
FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING PROCESS Ch. Fleck #,1 Th. Paulus, Steinbachstr. 54, DÂ52074 Aachen, Germany Abstract: Strip casting technology is the most recent innovative steel casting technology that integrates casting and rolling into a single production step. The strip
FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING
Ollivier, FranÃ§ois
FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING PROCESS Ch. Fleck ,1 Th. Paulus ,2, D-52074 Aachen, Germany Abstract: Strip casting technology is the most recent innovative steel casting technology that integrates casting and rolling into a single production step. The strip thickness
On One Master Integral for Three-loop On-shell HQET Propagator Diagrams with Mass
Grozin, A.G.; Huber, T.; Maitre, D.; /SLAC
2007-06-26
An exact expression for the master integral I{sub 2} [1] arising in three-loop on-shell HQET propagator diagrams with mass is derived and its analytical expansion in the dimensional regularization parameter {var_epsilon} is given.
Limitations, performance and instrumentation of closed-loop feedback based distributed adaptive
Beigl, Michael
Limitations, performance and instrumentation of closed-loop feedback based distributed adaptive performance. Finally, we present measure- ments from an instrumentation using USRP software radios at various. This is especially useful in large scale sensor networks since the number of potentially available nodes
Cool transition region loops observed by the Interface Region Imaging Spectrograph
by magnetic reconnection occurring at the blue-shifted footpoints where magnetic cancellation with a rate is reflected in the line profiles of explosive events, and a magnetic cancellation rate of 3 × 1015 Mx s-1 ob to 25 km s-1 were determined. These physical properties suggest that these loops are impulsively heated
A low phase noise ring oscillator phase-locked loop for wireless applications
Weltin-Wu, Colin
2005-01-01
This thesis describes the circuit level design of a 900MHz [Sigma][Detta] ring oscillator based phase-locked loop using 0.35[mu]m technology. Multiple phase noise theories are considered giving insight into low phase-noise ...
Evaluation of Novel Ceria-Supported Metal Oxides As Oxygen Carriers for Chemical-Looping Combustion
Azad, Abdul-Majeed
for copper-based materials, and at 950 °C for iron- and manganese-based materials. Methane or syngas (50% COEvaluation of Novel Ceria-Supported Metal Oxides As Oxygen Carriers for Chemical-Looping Combustion of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Goteborg, Sweden
New Loops! MiTeGen* 50MicroMountsTM consist of a thin microfabricated
Meagher, Mary
New Loops! MiTeGen* 50µMicroMountsTM consist of a thin microfabricated polyimide film attached to a solid non-magnetic stainless steel pin. The film is polyimide, which is used in Kapton® tape and is employed for X- ray transparent windows on X-ray beam lines. The film is curved by wrapping polyimide film
The Universal Central Extension of the Three-point sl_2 Loop Algebra
Georgia Benkart; Paul Terwilliger
2005-12-17
We give a presentation of the universal central extension of the three-point loop algebra L over sl_2 by generators and relations. Our presentation arises from the realization of L as the tetrahedron Lie algebra and leads to connections between the universal central extension and the Onsager Lie algebra. Symmetry under the alternating group A_4 features prominently in this work.
Helicoids, Wrinkles, and Loops in Twisted Ribbons Julien Chopin* and Arshad Kudrolli
Kudrolli, Arshad
subject to twist under tension and develop an integrated phase diagram of the observed shapes and transitions. We find that the primary buckling mode switches from being localized longitudinally along loop formation has been shown using numerical simulations [1315]. In the case where the rib- bon
Point particles in 2+1 dimensions: general relativity and loop gravity descriptions
Jonathan Ziprick
2014-09-26
We develop a Hamiltonian description of point particles in (2+1)-dimensions using connection and frame-field variables for general relativity. The topology of each spatial hypersurface is that of a punctured two-sphere with particles residing at the punctures. We describe this topology with a CW complex (a collection of two-cells glued together along edges), and use this to fix a gauge and reduce the Hamiltonian. The equations of motion for the fields describe a dynamical triangulation where each vertex moves according to the equation of motion for a free relativistic particle. The evolution is continuous except for when triangles collapse (i.e. the edges become parallel) causing discrete, topological changes in the underlying CW complex. We then introduce the loop gravity phase space parameterized by holonomy-flux variables on a graph (a network of one-dimensional links). By embedding a graph within the CW complex, we find a description of this system in terms of loop variables. The resulting equations of motion describe the same dynamical triangulation as the connection and frame-field variables. In this framework, the collapse of a triangle causes a discrete change in the underlying graph, giving a concrete realization of the graph-changing moves that many expect to feature in full loop quantum gravity. The main result is a dynamical model of loop gravity which agrees with general relativity and is well-suited for quantization using existing methods.
Modelling Rates of Gasification of a Char Particle in Chemical Looping Combustion
Saucedo, Marco A.; Dennis, John S.; Scott, Stuart A.
2014-07-15
Rates of gasification of lignite char were compared when gasification with CO2 was undertaken in a fluidised bed of either (i) an active Fe-based oxygen carrier used for chemical looping or (ii) inert sand. The kinetics of the gasification were...
Fractal Structure of Isothermal Lines and Loops on the Cosmic Microwave Background
Chiang, Lung-Yih
of isothermal lines and loops of the cosmic microwave background (CMB) radiation on the sky map is studied and the fractal structure is confirmed in the radiation temperature fluctuation. We estimate the fractal exponents of Hurst exponents, He for the profile of the CMB radiation temperature, and Hc for a single isothermal
CHIRON: a package for ChPT numerical results at two loops
Johan Bijnens
2014-12-02
This document describes the package CHIRON which includes two libraries, chiron itself and jbnumlib. CHIRON is a set of routines useful for two-loop numerical results in Chiral Perturbation Theory (ChPT). It includes programs for the needed one- and two-loop integrals as well as routines to deal with the ChPT parameters. The present version includes everything needed for the masses, decay constants and quark-antiquark vacuum-expectation-values. An added routine calculates consistent values for the masses and decay constants when the pion and kaon masses are varied. In addition a number of finite volume results are included: one-loop tadpole integrals, two-loop sunset integrals and the results for masses and decay constants. The numerical routine library jbnumlib contains the numerical routines used in chiron. Many are to a large extent simple C++ versions of routines in the CERNLIB numerical library. Notable exceptions are the dilogarithm and the Jacobi theta function implementations. This paper describes what is included in CHIRON v0.50.
Eddy currents in a gradient coil, modelled as circular loops of strips
Eindhoven, Technische Universiteit
Eddy currents in a gradient coil, modelled as circular loops of strips J.M.B. Kroot, S.J.L. van. Due to induction eddy currents occur which lead to the so-called edge-effect. The edge- effect depends the gradient coils themselves. Eddy currents occur, causing perturbations on the expected gradient field
Eddy currents in a gradient coil, modeled as circular loops of strips
Eindhoven, Technische Universiteit
Eddy currents in a gradient coil, modeled as circular loops of strips J.M.B. Kroot, S.J.L. van to induction, eddy currents occur, resulting in a so-called edge-effect. Higher frequencies cause stronger edge by a gradient coil induces eddy currents in the conducting structures. The eddy currents cause perturbations
Dynamically Feasible Trajectory and Open-Loop Control Design for Unmanned Airships
Papadopoulos, Evangelos
Dynamically Feasible Trajectory and Open-Loop Control Design for Unmanned Airships Filoktimon--This paper describes a method for planning six DOF trajectories for an underactuated unmanned airship the requirements of tracking the specific trajectory. I. INTRODUCTION Unmanned, robotic (autonomous) airships, see
Stem-loop Structure in the 5H Region of Potato Virus X
Brown, James W.
Stem-loop Structure in the 5H Region of Potato Virus X Genome Required for Plus-strand RNA 27695, USA Computer-generated thermodynamic predictions and solution structure probing indicated two nt of potato virus X (PVX) RNA. Because the existence of SL1 was further supported by co- variation
Motor Modeling and Position Control Lab Week 3: Closed Loop Control
Krovi, Venkat
Motor Modeling and Position Control Lab Week 3: Closed Loop Control 1. Review In the first week of motor modeling lab, a mathematical model of a DC motor from first principles was derived to obtain specifically for this motor model. In the second week, a physical DC motor (Quanser SRV-02) was used for open
Higgs decay to two photons at one-loop in the SMEFT
Christine Hartmann; Michael Trott
2015-10-29
We present the calculation of the $\\rm CP$ conserving contributions to $\\Gamma(h \\rightarrow \\gamma \\gamma)$, from dimension six operators at one-loop order, in the linear Standard Model Effective Field Theory. We discuss the impact of these corrections on interpreting current and future experimental bounds on this decay.
Fourier analysis and systems identification of the p53 feedback loop
to a circuit, measures its output at different frequencies, and describes this by linear models of the dynamicsFourier analysis and systems identification of the p53 feedback loop Naama Geva-Zatorskya,1 , Erez (received for review January 31, 2010) A key circuit in the response of cells to damage is the p53mdm2
Transverse oscillations in solar coronal loops induced by propagating Alfvenic pulses
Luca Del Zanna; Eveline Schaekens; Marco Velli
2004-11-24
The propagation and the evolution of Alfvenic pulses in the solar coronal arcades is investigated by means of MHD numerical simulations. Significant transverse oscillations in coronal loops, triggered by nearby flare events, are often measured in EUV lines and are generally interpreted as standing kink modes. However, the damping times of these oscillations are typically very short (from one to a few periods) and the physical mechanism responsible for the decay is still a matter of debate. Moreover, the majority of the observed cases actually appears to be better modeled by propagating, rather than standing, modes. Here we perform 2.5-D compressible MHD simulations of impulsively generated Alfven waves propagating in a potential magnetic arcade (assumed as a simplified 2-D loop model), taking into account the stratification of the solar atmosphere with height from the photosphere to the corona. The results show a strong spreading of the initially localized pulses along the loop, due to the variations in the Alfven velocity with height, and correspondingly an efficient damping of the amplitude of the oscillations. We believe that simple explanations based on the effects of wave propagation in highly inhomogeneous media may apply to the majority of the reported cases, and that variations of the background density and Alfven speed along the loop should be considered as key ingredients in future models.
2-Loop Functional Renormalization Group Theory of the Depinning Transition Pierre Le Doussal1
Wiese, Kay Jörg
simulations. The high value of 0.5 found in experiments both on the contact line depinning of liquid Helium2-Loop Functional Renormalization Group Theory of the Depinning Transition Pierre Le Doussal1 , Kay and elastic periodic systems at zero temperature, taking properly into account the non- analytic form
Two-loop functional renormalization group theory of the depinning transition Pierre Le Doussal,1
Wiese, Kay Jörg
with simulations. The high value of 0.5 in experiments both on Helium contact line depinning and on slow crackTwo-loop functional renormalization group theory of the depinning transition Pierre Le Doussal,1 at zero temperature, taking properly into account the nonanalytic form of the dynamical action. This cures
Understanding operational regimes of closed loop pulsating heat pipes: an experimental study
Khandekar, Sameer
Understanding operational regimes of closed loop pulsating heat pipes: an experimental study Sameer are proven solutions for modern microelectronics thermal management. In this context, heat pipe research is being continuously pursued evolving newer solutions to suit present requirements. Pulsating heat pipes
LONG EXPOSURE POINT SPREAD FUNCTION ESTIMATION FROM SOLAR ADAPTIVE OPTICS LOOP DATA
Astronomer, National Solar Observatory, New Mexico, USA Dr. Haimin Wang, Dissertation Co-Advisor DateABSTRACT LONG EXPOSURE POINT SPREAD FUNCTION ESTIMATION FROM SOLAR ADAPTIVE OPTICS LOOP DATA during solar observations due to the lack of point sources in the field-of-view. Moreover, the highly
Closing the Learning-Planning Loop with PSRs Byron Boots beb@cs.cmu.edu
Gordon, Geoffrey J.
Closing the Learning-Planning Loop with PSRs Byron Boots beb@cs.cmu.edu Sajid M. Siddiqi* siddiqi under grant number 4400161514, and a project with MobileFusion/TTC. BEB was supported by the NSF under grant number EEEC-0540865. BEB and GJG were both supported by ONR MURI grant number N00014
Electric-Magnetic duality and the "Loop Representation" in Abelian Gauge Theories
Lorenzo Leal
1996-03-01
Abelian Gauge Theories are quantized in a geometric representation that generalizes the Loop Representation and treates electric and magnetic operators on the same footing. The usual canonical algebra is turned into a topological algebra of non local operators that resembles the order-disorder dual algebra of 't Hooft. These dual operators provide a complete description of the physical phase space of the theories.
Structural properties of the histidine-containing loop in HIV-1RNase H
Kern, G.; Pelton, J.; Marqusee, S.; Kern, D.
2001-01-02
The isolated HIV-1 RNase H domain is inactive. This inactivity has been linked to the lack of structure in the C-terminus of the isolated domain. His539 residing in a loop preceding the C-terminal Helix was studies by NMR to determine the stability and conformational properties of this region.
Hydrogen-bond driven loop-closure kinetics in unfolded polypeptide chains
Daidone, Isabella [University of Heidelberg; Neuweiler, H [University of Heidelberg; Doose, S [University of Heidelberg; Sauer, M [University of Heidelberg; Smith, Jeremy C [ORNL
2010-12-01
Characterization of the length dependence of end-to-end loop-closure kinetics in unfolded polypeptide chains provides an understanding of early steps in protein folding. Here, loop-closure in poly-glycine-serine peptides is investigated by combining single-molecule fluorescence spectroscopy with molecular dynamics simulation. For chains containing more than 10 peptide bonds loop-closing rate constants on the 20-100 nanosecond time range exhibit a power-law length dependence. However, this scaling breaks down for shorter peptides, which exhibit slower kinetics arising from a perturbation induced by the dye reporter system used in the experimental setup. The loop-closure kinetics in the longer peptides is found to be determined by the formation of intra-peptide hydrogen bonds and transient beta-sheet structure, that accelerate the search for contacts among residues distant in sequence relative to the case of a polypeptide chain in which hydrogen bonds cannot form. Hydrogen-bond-driven polypeptide-chain collapse in unfolded peptides under physiological conditions found here is not only consistent with hierarchical models of protein folding, that highlights the importance of secondary structure formation early in the folding process, but is also shown to speed up the search for productive folding events.
One-loop fluctuations of semi-local self-dual vortices
A. Alonso Izquierdo; W. Garcia Fuertes; M. de la Torre Mayado; J. Mateos Guilarte
2008-01-22
Mass shifts induced by one-loop fluctuations of semi-local self-dual vortices are computed. The procedure is based on canonical quantization and heat kernel/ zeta function regularization methods. The issue of the survival of the classical degeneracy in the semi-classical regime is explored.
Design of CMOS integrated phase-locked loops for multi-gigabits serial data links
Cheng, Shanfeng
2007-04-25
links are able to achieve higher data rate and longer transfer distance. This dissertation is focused on the design of CMOS integrated phase-locked loops (PLLs) and relevant building blocks used in multi-gigabits serial data link transceivers. Firstly...
Hardware-in-the-loop testing of wireless systems in realistic environments.
Burkholder, R. J. (Ohio State University ElectroScience Laboratory); Mariano, Robert J.; Gupta, I. J. (Ohio State University ElectroScience Laboratory); Schniter, P. (Ohio State University ElectroScience Laboratory)
2006-06-01
This document describes an approach for testing of wireless systems in realistic environments that include intentional as well as unintentional radio frequency interference. In the approach, signal generators along with radio channel simulators are used to carry out hardware-in-the-loop testing. The channel parameters are obtained independently via channel sounding measurements and/or EM simulations.
Computational fluid dynamic simulations of chemical looping fuel reactors utilizing gaseous fuels
Mahalatkar, K.; Kuhlman, J.; Huckaby, E.D.; O'Brien, T.
2011-01-01
A computational fluid dynamic(CFD) model for the fuel reactor of chemical looping combustion technology has been developed,withspecialfocusonaccuratelyrepresentingtheheterogeneous chemicalreactions.Acontinuumtwo-fluidmodelwasusedtodescribeboththegasandsolidphases. Detailedsub-modelstoaccountforfluid–particleandparticle–particleinteractionforceswerealso incorporated.Twoexperimentalcaseswereanalyzedinthisstudy(Son andKim,2006; Mattisonetal., 2001). SimulationswerecarriedouttotestthecapabilityoftheCFDmodeltocapturechangesinoutletgas concentrationswithchangesinnumberofparameterssuchassuperficialvelocity,metaloxide concentration,reactortemperature,etc.Fortheexperimentsof Mattissonetal.(2001), detailedtime varyingoutletconcentrationvalueswerecompared,anditwasfoundthatCFDsimulationsprovideda reasonablematchwiththisdata.
Effects on UV line observations of stationary plasma flows confined in coronal loops
hosting a siphon flow as a diagnostic tool to interpret solar UV and X--ray observations in selected bands be different at the two footpoints and could drive a significant plasma flow (siphon flow) along the loop case, the detection of possible asymmetries may be the key to show or to exclude evidence of a siphon
Higgs decay to two photons at one-loop in the SMEFT
Hartmann, Christine
2015-01-01
We present the calculation of the $\\rm CP$ conserving contributions to $\\Gamma(h \\rightarrow \\gamma \\gamma)$, from dimension six operators at one-loop order, in the linear Standard Model Effective Field Theory. We discuss the impact of these corrections on interpreting current and future experimental bounds on this decay.
The Energy Impact of Aggressive Loop Fusion YongKang Zhu , Grigorios Magklis
Scott, Michael L.
The Energy Impact of Aggressive Loop Fusion YongKang Zhu , Grigorios Magklis , Michael L. Scott effect on energy. By merging program phases, fusion tends to increase the uniformity, or balance to increase IPC, and thus dynamic power, so that fusion-induced improvements in program energy are slightly
Closing the Loop on Big Data Rob Nowak www.ece.wisc.edu/~nowak
Qiu, Robert Caiming
Closing the Loop on Big Data data Rob Nowak www.ece.wisc.edu/~nowak NSF Big Data Workshop March 21, 2013 #12;model space questions /queries "training data" BIG DATA: A Marriage of Machine and Man Human Judgements labeling, annotation, comparisons #12;model space questions /queries "training data" BIG DATA
Guan, W.; Liu, M.; Wang, J.
1998-01-01
The impacts of the water loop management on the heating and cooling energy consumption are investigated by using model simulation. The simulation results show that the total thermal energy consumption can be increased by 24% for a typical AHU in San...
Schrijver, Karel
Martin Advanced Technology Center, Solar and Astrophysics Laboratory, Department L9-41, Bld.252., 3251 (half) length L and orientation of the loop plane, based on a best-fit of a circular geometry. Then we of kink eigen-mode oscillations, but rather manifest flare-induced impulsively generated MHD waves, which
POISONED FEEDBACK: THE IMPACT OF MALICIOUS USERS IN CLOSED-LOOP MULTIUSER MIMO SYSTEMS
Swindlehurst, A. Lee
POISONED FEEDBACK: THE IMPACT OF MALICIOUS USERS IN CLOSED-LOOP MULTIUSER MIMO SYSTEMS Amitav systems based on malicious feedback of CSI. In particular, we examine malicious or poisoned feedback of the trans- mitter are listed in Sec. 3. Numerical results that depict the impact of poisoned feedback
Numerical evaluation of one-loop diagrams near exceptional momentum configurations
Walter T Giele; Giulia Zanderighi; E.W.N. Glover
2004-07-06
One problem which plagues the numerical evaluation of one-loop Feynman diagrams using recursive integration by part relations is a numerical instability near exceptional momentum configurations. In this contribution we will discuss a generic solution to this problem. As an example we consider the case of forward light-by-light scattering.
Two-loop Master Integrals with the Simplified Differential Equations approach
Costas G. Papadopoulos; Damiano Tommasini; Christopher Wever
2015-07-21
We calculate the complete set of two-loop Master Integrals with two off mass-shell legs with massless internal propagators, that contribute to amplitudes of diboson $V_1V_2$ production at the LHC. This is done with the Simplified Differential Equations approach to Master Integrals, which was recently proposed by one of the authors.
One-loop pentagon integral in $d$ dimensions from differential equations in $?$-form
Mikhail G. Kozlov; Roman N. Lee
2015-12-16
We apply the differential equation technique to the calculation of the one-loop massless diagram with five onshell legs. Using the reduction to $\\epsilon$-form, we manage to obtain a simple one-fold integral representation exact in space-time dimensionality. The expansion of the obtained result in $\\epsilon$ and the analytical continuation to physical regions are discussed.
Towards Understanding Architectural Tradeoffs in MEMS Closed-Loop Feedback Control
Sherwood, Tim
Towards Understanding Architectural Tradeoffs in MEMS Closed-Loop Feedback Control Greg Hoover, California 93106 sherwood@cs.ucsb.edu ABSTRACT Micro-Electro-Mechanical Systems (MEMS) combine litho on the scale of microns. However, the physical scale of MEMS devices can make controlling them computationally
Tuning of MEMS devices using Evolutionary Computation and Open-Loop Frequency Response.
Arizona, University of
1 Tuning of MEMS devices using Evolutionary Computation and Open-Loop Frequency Response. Didier.keymeulen@jpl.nasa.gov Abstract-- 12 We propose a tuning method for MEMS gyroscopes based on evolutionary computation that has the capacity to efficiently increase the sensitivity of MEMS gyroscopes through tuning and, furthermore
Hammock, Bruce D.
microorganisms,10,11 genetically modified ingredients,12,13 tumor detection,14,15 and embryo sex identification 95616, United States Guangdong Provincial Key Laboratory of Food Quality and Safety, South China pesticides and their residues in food and the environment. Loop-mediated isothermal amplification (LAMP
Polymers in poor solvents : loop expansion of irreducible diagrams (II) J. des Cloizeaux
Boyer, Edmond
761 Polymers in poor solvents : loop expansion of irreducible diagrams (II) J. des Cloizeaux polydispersion. Abstract. 2014 Properties of polymers in poor solvent are found by calculating irreducible. Expressions are given for the osmotic pressure, the size of a polymer in a solution and the density
An enumerative stepwise ansatz enables atomic-accuracy RNA loop modeling
Das, Rhiju
demonstrate that the predictive power of computational algo- rithms remains limited, especially if atomicAn enumerative stepwise ansatz enables atomic-accuracy RNA loop modeling Parin Sripakdeevonga September 27, 2011 (received for review May 17, 2011) Atomic-accuracy structure prediction of macromolecules
Complete electroweak one-loop radiative corrections to top-pair production at TESLA -- a comparison
J. Fleischer; T. Hahn; W. Hollik; T. Riemann; C. Schappacher; A. Werthenbach
2002-09-19
Electroweak one-loop radiative corrections to the process e^+ e^- -> t tbar are revisited. Two groups from Karlsruhe and Bielefeld/Zeuthen performed independent calculations of both (virtual and soft) QED contributions and weak virtual corrections. For the angular distribution an agreement of at least eight digits for the weak corrections and of at least seven digits for additional photonic corrections is established.
A Numerical Approach to the Kinematic Analysis of Deployable Structures forming a Closed Loop
Pellegrino, Sergio
A Numerical Approach to the Kinematic Analysis of Deployable Structures forming a Closed Loop W This paper is concerned with the kinematics of deployable structures, based on the concept of a mechanical, CB2 1PZ, UK. pellegrino@eng.cam.ac.uk March 20, 2006 Keywords: Deployable structures, kinematic
Sampling-Based Motion Planning under Kinematic Loop-Closure Constraints
Cortés, Juan
). Complex articulated mechanisms with closed kinematic chains appear in all the domains where motion- ple closed kinematic chains. biology for the structural analysis of protein loops. All. Basically, motion constraints are due to the kinematic structure of the mechanism and to collision avoid
Verifiable Active Safety for Automotive Cyber-Physical Systems with Humans in the Loop
Rajkumar, Ragunathan "Raj"
Verifiable Active Safety for Automotive Cyber-Physical Systems with Humans in the Loop Francesco-6925 A recent trend in the automotive industry is the rapid inclusion of electronics, computers and controls that focus entirely on improved functionality and overall system robustness. This makes the automotive sector
Akihiro Shibata; Kei-Ichi Kondo; Seikou Kato; Shoichi Ito; Toru Shinohara; Nobuyui Fukui
2009-11-24
We have given a new description of the lattice Yang-Mills theory a la Cho-Faddeev-Niemi-Shabanov, which has enabled us to confirm in a gauge-independent manner "Abelian"-dominance and magnetic-monopole dominance in the Wilson loop average, yielding a gauge-independent dual superconductor picture for quark confinement. In particular, we have given a new procedure (called reduction) for obtaining a gauge-independent magnetic monopole from a given Yang-Mills field. In this talk, we demonstrate how some of known topological configurations in the SU(2) Yang-Mills theory such as merons and instantons generate closed loops of magnetic-monopole current as the quark confiner, both of which are characterized by the gauge-invariant topological index, topological charge (density) and magnetic charge (density), respectively. We also try to detect which type of topological configurations exist in the lattice data involving magnetic-monopole loops generated by Monte Carlo simulation. Here we apply a new geometrical algorithm based on "computational homology" to discriminating each closed loop from clusters of magnetic-monopole current, since the magnetic-monopole current on a lattice is integer valued.
Positive Cross-Regulatory Loop Ties GATA-3 to Estrogen Receptor A Expression in Breast Cancer
Brown, Myles
Positive Cross-Regulatory Loop Ties GATA-3 to Estrogen Receptor A Expression in Breast Cancer Je, the functional role of GATA-3 in ERA- positive breast cancers is yet to be established. Here, we show that GATA-3 is required for estradiol stimulation of cell cycle progression in breast cancer cells. The role of GATA-3
Enhancement of the LFV Higgs decay rates from SUSY loops in the Inverse Seesaw Model
Arganda, E; Marcano, X; Weiland, C
2015-01-01
In this letter we study the full one-loop SUSY contributions to the lepton flavor violating Higgs decay $h \\to \\tau \\bar \\mu $, within the context of the Supersymmetric Inverse Seesaw Model. We assume that both the right-handed neutrino masses, $M_R$, and their supersymmetric partner masses, $m_{\\tilde \
Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)
2002-01-01
Architecture for frequency multiplexing multiple flux locked loops in a system comprising an array of DC SQUID sensors. The architecture involves dividing the traditional flux locked loop into multiple unshared components and a single shared component which, in operation, form a complete flux locked loop relative to each DC SQUID sensor. Each unshared flux locked loop component operates on a different flux modulation frequency. The architecture of the present invention allows a reduction from 2N to N+1 in the number of connections between the cryogenic DC SQUID sensors and their associated room temperature flux locked loops. Furthermore, the 1.times.N architecture of the present invention can be paralleled to form an M.times.N array architecture without increasing the required number of flux modulation frequencies.
Evolution of the Loop-Top Source of Solar Flares--Heating and Cooling Processes
Yan Wei Jiang; Siming Liu; Wei Liu; Vahe Petrosian
2005-08-24
We present a study of the spatial and spectral evolution of the loop-top (LT) sources in a sample of 6 flares near the solar limb observed by {\\it RHESSI}. A distinct coronal source, which we identify as the LT source, was seen in each of these flares from the early ``pre-heating'' phase through the late decay phase. Spectral analyses reveal an evident steep power-law component in the pre-heating and impulsive phases, suggesting that the particle acceleration starts upon the onset of the flares. In the late decay phase the LT source has a thermal spectrum and appears to be confined within a small region near the top of the flare loop, and does not spread throughout the loop, as is observed at lower energies. The total energy of this source decreases usually faster than expected from the radiative cooling but much slower than that due to the classical Spitzer conductive cooling along the flare loop. These results indicate the presence of a distinct LT region, where the thermal conductivity is suppressed significantly and/or there is a continuous energy input. We suggest that plasma wave turbulence could play important roles in both heating the plasma and suppressing the conduction during the decay phase of solar flares. With a simple quasi-steady loop model we show that the energy input in the gradual phase can be comparable to that in the impulsive phase and demonstrate how the observed cooling and confinement of the LT source can be used to constrain the wave-particle interaction.
Strategic Need for Multi-Purpose Thermal Hydraulic Loop for Support of Advanced Reactor Technologies
James E. O'Brien; Piyush Sabharwall; Su-Jong Yoon; Gregory K. Housley
2014-09-01
This report presents a conceptual design for a new high-temperature multi fluid, multi loop test facility for the INL to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications. In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs) at prototypical operating conditions, flow and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for LWRs at prototypical conditions. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. Research performed in this facility will advance the state of the art and technology readiness level of high temperature intermediate heat exchangers (IHXs) for nuclear applications while establishing the INL as a center of excellence for the development and certification of this technology. The thermal energy storage capability will support research and demonstration activities related to process heat delivery for a variety of hybrid energy systems and grid stabilization strategies. Experimental results obtained from this research will assist in development of reliable predictive models for thermal hydraulic design and safety codes over the range of expected advanced reactor operating conditions. Proposed/existing IHX heat transfer and friction correlations and criteria will be assessed with information on materials compatibility and instrumentation needs. The experimental database will guide development of appropriate predictive methods and be available for code verification and validation (V&V) related to these systems.
Dominic J. O'. Lee
2015-04-17
Presented here, is a technical manuscript that may form the basis of later published work. In it, we develop a statistical mechanical model to describe a closed loop plectoneme, applicable for when the closed loop is sufficiently supercoiled. The model divides the system up into end loops and a braided section; the end loops are assumed to contribute little to the super-coil writhe. Within the braided section, the model incorporates interactions that depend on the structure of the molecule; in particular, we consider those that depend on helical structure. A method for approximating the steric interactions is utilized that we had previously used in other publications. We go on to construct variational approximations for our closed loop plectoneme model in two cases. The first case is where helix dependent interactions are strong, and in the second case they are considered weak. In developing these approximations, we approximate the Fuller-White condition by replacing, in all expressions that depend on twist, writhe with average writhe, valid when the braided section is sufficiently long. How this approximation is made and the conditions when this approximation is valid are also discussed. The approximation allows for a Legendre transformation of the free energy, which with the introduction of moment (or torque), effectively allowing for twist and average writhe to be treated independently in the transformed (Gibbs like) free energy. Next, we then show how one may compute the average writhe of the braided section. Lastly, we discuss how some of the approximations considered may be relaxed, and discuss how the resulting model free energy might be computed by MC simulation.
Dismantling of Loop-Type Channel Equipment of MR Reactor in NRC 'Kurchatov Institute' - 13040
Volkov, Victor; Danilovich, Alexey; Zverkov, Yuri; Ivanov, Oleg; Kolyadin, Vyacheslav; Lemus, Alexey; Pavlenko, Vitaly; Semenov, Sergey; Fadin, Sergey; Shisha, Anatoly; Chesnokov, Alexander
2013-07-01
In 2009 the project of decommissioning of MR and RTF reactors was developed and approved by the Expert Authority of the Russian Federation (Gosexpertiza). The main objective of the decommissioning works identified in this project: - complete dismantling of reactor equipment and systems; - decontamination of reactor premises and site in accordance with the established sanitary and hygienic standards. At the preparatory stage (2008-2010) of the project the following works were executed: loop-type channels' dismantling in the storage pool; experimental fuel assemblies' removal from spent fuel repositories in the central hall; spent fuel assembly removal from the liquid-metal-cooled loop-type channel of the reactor core and its placement into the SNF repository; and reconstruction of engineering support systems to the extent necessary for reactor decommissioning. The project assumes three main phases of dismantling and decontamination: - dismantling of equipment/pipelines of cooling circuits and loop-type channels, and auxiliary reactor equipment (2011-2012); - dismantling of equipment in underground reactor premises and of both MR and RTF in-vessel devices (2013-2014); - decontamination of reactor premises; rehabilitation of the reactor site; final radiation survey of reactor premises, loop-type channels and site; and issuance of the regulatory authorities' de-registration statement (2015). In 2011 the decommissioning license for the two reactors was received and direct MR decommissioning activities started. MR primary pipelines and loop-type facilities situated in the underground reactor hall were dismantled. Works were also launched to dismantle the loop-type channels' equipment in underground reactor premises; reactor buildings were reconstructed to allow removal of dismantled equipment; and the MR/RTF decommissioning sequence was identified. In autumn 2011 - spring 2012 results of dismantling activities performed are: - equipment from underground rooms (No. 66, 66A, 66B, 72, 64, 63) - as well as from water and gas loop corridors - was dismantled, with the total radwaste weight of 53 tons and the total removed activity of 5,0 x 10{sup 10} Bq; - loop-type channel equipment from underground reactor hall premises was dismantled; - 93 loop-type channels were characterized, chopped and removed, with radwaste of 2.6 x 10{sup 13} Bq ({sup 60}Co) and 1.5 x 10{sup 13} Bq ({sup 137}Cs) total activity removed from the reactor pool, fragmented and packaged. Some of this waste was placed into the high-level waste (HLW) repository of the Center. Dismantling works were executed with application of remotely operated mechanisms, which promoted decrease of radiation impact on the personnel. The average individual dose for the personnel was 1.9 mSv/year in 2011, and the collective dose is estimated as 0.0605 man x Sv/year. (authors)
Non-equilibrium of Ionization and the Detection of Hot Plasma in Nanoflare-heated Coronal Loops
Fabio Reale; Salvatore Orlando
2008-05-22
Impulsive nanoflares are expected to transiently heat the plasma confined in coronal loops to temperatures of the order of 10 MK. Such hot plasma is hardly detected in quiet and active regions, outside flares. During rapid and short heat pulses in rarified loops the plasma can be highly out of equilibrium of ionization. Here we investigate the effects of the non-equilibrium of ionization (NEI) on the detection of hot plasma in coronal loops. Time-dependent loop hydrodynamic simulations are specifically devoted to this task, including saturated thermal conduction, and coupled to the detailed solution of the equations of ionization rate for several abundant elements. In our simulations, initially cool and rarified magnetic flux tubes are heated to 10 MK by nanoflares deposited either at the footpoints or at the loop apex. We test for different pulse durations, and find that, due to NEI effects, the loop plasma may never be detected at temperatures above ~5 MK for heat pulses shorter than about 1 min. We discuss some implications in the framework of multi-stranded nanoflare-heated coronal loops.
Yan, X. L.; Qu, Z. Q.; Xue, Z. K.; Deng, L. H.; Ma, L.; Kong, D. F.; Liu, J. H.
2013-06-15
We present an observation of overlying coronal loop contraction and rotating motion of the sigmoid filament during its eruption on 2012 May 22 observed by the Solar Dynamics Observatory (SDO). Our results show that the twist can be transported into the filament from the lower atmosphere to the higher atmosphere. The successive contraction of the coronal loops was due to a suddenly reduced magnetic pressure underneath the filament, which was caused by the rising of the filament. Before the sigmoid filament eruption, there was a counterclockwise flow in the photosphere at the right feet of the filament and the contraction loops and a convergence flow at the left foot of the filament. The hot and cool materials have inverse motion along the filament before the filament eruption. Moreover, two coronal loops overlying the filament first experienced brightening, expansion, and contraction successively. At the beginning of the rising and rotation of the left part of the filament, the second coronal loop exhibited rapid contraction. The top of the second coronal loop also showed counterclockwise rotation during the contraction process. After the contraction of the second loop, the left part of the filament rotated counterclockwise and expanded toward the right of NOAA AR 11485. During the filament expansion, the right part of the filament also exhibited counterclockwise rotation like a tornado.
Well-observed dynamics of flaring and peripheral coronal magnetic loops during an M-class limb flare
Shen, Jinhua; Zhou, Tuanhui; Ji, Haisheng; Feng, Li; Wiegelmann, Thomas; Inhester, Bernd
2014-08-20
In this paper, we present a variety of well-observed dynamic behaviors for the flaring and peripheral magnetic loops of the M6.6 class extreme limb flare that occurred on 2011 February 24 (SOL2011-02-24T07:20) from EUV observations by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory and X-ray observations by RHESSI. The flaring loop motion confirms the earlier contraction-expansion picture. We find that the U-shaped trajectory delineated by the X-ray corona source of the flare roughly follows the direction of a filament eruption associated with the flare. Different temperature structures of the coronal source during the contraction and expansion phases strongly suggest different kinds of magnetic reconnection processes. For some peripheral loops, we discover that their dynamics are closely correlated with the filament eruption. During the slow rising to abrupt, fast rising of the filament, overlying peripheral magnetic loops display different responses. Two magnetic loops on the elbow of the active region had a slow descending motion followed by an abrupt successive fast contraction, while magnetic loops on the top of the filament were pushed outward, slowly being inflated for a while and then erupting as a moving front. We show that the filament activation and eruption play a dominant role in determining the dynamics of the overlying peripheral coronal magnetic loops.
Analytic Result for the Two-loop Six-point NMHV Amplitude in N = 4 Super Yang-Mills Theory
Dixon, Lance J.; Drummond, James M.; Henn, Johannes M.; /Humboldt U., Berlin /Princeton, Inst. Advanced Study
2012-02-15
We provide a simple analytic formula for the two-loop six-point ratio function of planar N = 4 super Yang-Mills theory. This result extends the analytic knowledge of multi-loop six-point amplitudes beyond those with maximal helicity violation. We make a natural ansatz for the symbols of the relevant functions appearing in the two-loop amplitude, and impose various consistency conditions, including symmetry, the absence of spurious poles, the correct collinear behavior, and agreement with the operator product expansion for light-like (super) Wilson loops. This information reduces the ansatz to a small number of relatively simple functions. In order to fix these parameters uniquely, we utilize an explicit representation of the amplitude in terms of loop integrals that can be evaluated analytically in various kinematic limits. The final compact analytic result is expressed in terms of classical polylogarithms, whose arguments are rational functions of the dual conformal cross-ratios, plus precisely two functions that are not of this type. One of the functions, the loop integral {Omega}{sup (2)}, also plays a key role in a new representation of the remainder function R{sub 6}{sup (2)} in the maximally helicity violating sector. Another interesting feature at two loops is the appearance of a new (parity odd) x (parity odd) sector of the amplitude, which is absent at one loop, and which is uniquely determined in a natural way in terms of the more familiar (parity even) x (parity even) part. The second non-polylogarithmic function, the loop integral {tilde {Omega}}{sup (2)}, characterizes this sector. Both {Omega}{sup (2)} and {tilde {Omega}}{sup (2)} can be expressed as one-dimensional integrals over classical polylogarithms with rational arguments.
Dynamical quark loop light-by-light contribution to muon g-2 within the nonlocal chiral quark model
A. E. Dorokhov; A. E. Radzhabov; A. S. Zhevlakov
2015-07-24
The hadronic corrections to the muon anomalous magnetic moment a_mu, due to the gauge-invariant set of diagrams with dynamical quark loop light-by-light scattering insertions, are calculated in the framework of the nonlocal chiral quark model. These results complete calculations of all hadronic light-by-light scattering contributions to a_mu in the leading order in the 1/Nc expansion. The result for the quark loop contribution is a_mu^{HLbL,Loop}=(11.0+-0.9)*10^(-10), and the total result is a_mu^{HLbL,NxQM}=(16.8+-1.2)*10^(-10).
Probing deconfinement in a chiral effective model with Polyakov loop at imaginary chemical potential
Morita, Kenji [GSI, Helmholzzentrum fuer Schwerionenforschung, Planckstr. 1, D-64291 Darmstadt (Germany); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Skokov, Vladimir; Friman, Bengt [GSI, Helmholzzentrum fuer Schwerionenforschung, Planckstr. 1, D-64291 Darmstadt (Germany); Redlich, Krzysztof [Institute of Theoretical Physics, University of Wroclaw, PL-50204 Wroclaw (Poland); Extreme Matter Institute EMMI, GSI, Planckstr. 1, D-64291 Darmstadt (Germany)
2011-10-01
The phase structure of the two-flavor Polyakov-loop extended Nambu-Jona-Lashinio model is explored at finite temperature and imaginary chemical potential with a particular emphasis on the confinement-deconfinement transition. We point out that the confined phase is characterized by a cos3{mu}{sub I}/T dependence of the chiral condensate on the imaginary chemical potential while in the deconfined phase this dependence is given by cos{mu}{sub I}/T and accompanied by a cusp structure induced by the Z(3) transition. We demonstrate that the phase structure of the model strongly depends on the choice of the Polyakov loop potential U. Furthermore, we find that by changing the four fermion coupling constant G{sub s}, the location of the critical end point of the deconfinement transition can be moved into the real chemical potential region. We propose a new parameter characterizing the confinement-deconfinement transition.
Package-X: A Mathematica package for the analytic calculation of one-loop integrals
Hiren H. Patel
2015-09-04
Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of UV divergent, IR divergent, and finite parts for any kinematic configuration involving real-valued external invariants and internal masses. Output expressions can be readily evaluated numerically and manipulated symbolically with built-in Mathematica functions. Emphasis is on evaluation speed, on readability of results, and especially on user-friendliness. Also included is a routine to compute traces of products of Dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one-loop. The package is intended to be used both as a research tool and as an educational tool.
On-Shell Methods for the Two-Loop Dilatation Operator and Finite Remainders
Florian Loebbert; Dhritiman Nandan; Christoph Sieg; Matthias Wilhelm; Gang Yang
2015-10-05
We compute the two-loop minimal form factors of all operators in the SU(2) sector of planar N=4 SYM theory via on-shell unitarity methods. From the UV divergence of this result, we obtain the two-loop dilatation operator in this sector. Furthermore, we calculate the corresponding finite remainder functions. Since the operators break the supersymmetry, the remainder functions do not have the property of uniform transcendentality. However, the leading transcendentality part turns out to be universal and is identical to the corresponding BPS expressions. The remainder functions are shown to satisfy linear relations which can be explained by Ward identities of form factors following from R-symmetry.
One-Loop Partition Functions in Deformed $\\mathcal{N}=4$ SYM Theory
Jan Fokken; Matthias Wilhelm
2015-03-26
We study the thermodynamic behaviour of the real $\\beta$- and $\\gamma_i$-deformation of $\\mathcal{N}=4$ Super Yang-Mills theory on $\\mathbb{R}\\times S^3$ in the planar limit. These theories were shown to be the most general asymptotically integrable supersymmetric and non-supersymmetric field-theory deformations of $\\mathcal{N}=4$ Super Yang-Mills theory, respectively. We calculate the first loop correction to their partition functions using an extension of the dilatation-operator and P\\'{o}lya-counting approach. In particular, we account for the one-loop finite-size effects which occur for operators of length one and two. Remarkably, we find that the $\\mathcal{O}(\\lambda)$ correction to the Hagedorn temperature is independent of the deformation parameters, although the partition function depends on them in a non-trivial way.
Package-X: A Mathematica package for the analytic calculation of one-loop integrals
Hiren H. Patel
2015-03-04
Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of UV divergent, IR divergent, and finite parts for any kinematic configuration involving real-valued external invariants and internal masses. Output expressions can be readily evaluated numerically and manipulated symbolically with built-in Mathematica functions. Emphasis is on evaluation speed, on readability of results, and especially on user-friendliness. Also included is a routine to compute traces of products of Dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one-loop. The package is intended to be used both as a research tool and as an educational tool.
Crystalline Ground States in Polyakov-loop extended Nambu--Jona-Lasinio Models
Jens Braun; Felix Karbstein; Stefan Rechenberger; Dietrich Roscher
2015-10-14
Nambu--Jona-Lasinio-type models have been used extensively to study the dynamics of the theory of the strong interaction at finite temperature and quark chemical potential on a phenomenological level. In addition to these studies, which are often performed under the assumption that the ground state of the theory is homogeneous, searches for the existence of crystalline phases associated with inhomogeneous ground states have attracted a lot of interest in recent years. In this work, we study the Polyakov-loop extended Nambu--Jona-Lasinio model and find that the existence of a crystalline phase is stable against a variation of the parametrization of the underlying Polyakov loop potential. To this end, we adopt two prominent parametrizations. Moreover, we observe that the existence of a quarkyonic phase depends crucially on the parametrization, in particular in the regime of the phase diagram where inhomogeneous chiral condensation is favored.
Crystalline Ground States in Polyakov-loop extended Nambu--Jona-Lasinio Models
Braun, Jens; Rechenberger, Stefan; Roscher, Dietrich
2015-01-01
Nambu--Jona-Lasinio-type models have been used extensively to study the dynamics of the theory of the strong interaction at finite temperature and quark chemical potential on a phenomenological level. In addition to these studies, which are often performed under the assumption that the ground state of the theory is homogeneous, searches for the existence of crystalline phases associated with inhomogeneous ground states have attracted a lot of interest in recent years. In this work, we study the Polyakov-loop extended Nambu--Jona-Lasinio model and find that the existence of a crystalline phase is stable against a variation of the parametrization of the underlying Polyakov loop potential. To this end, we adopt two prominent parametrizations. Moreover, we observe that the existence of a quarkyonic phase depends crucially on the parametrization, in particular in the regime of the phase diagram where inhomogeneous chiral condensation is favored.
Andrea Costa; Rafael Gonzalez
2007-06-08
We study the modes and stability of non - isothermal coronal loop models with different intensity values of the equilibrium magnetic field. We use an energy principle obtained via non - equilibrium thermodynamic arguments. The principle is expressed in terms of Hermitian operators and allow to consider together the coupled system of equations: the balance of energy equation and the equation of motion. We determine modes characterized as long - wavelength disturbances that are present in inhomogeneous media. This character of the system introduces additional difficulties for the stability analysis because the inhomogeneous nature of the medium determines the structure of the disturbance, which is no longer sinusoidal. Moreover, another complication is that we obtain a continuous spectrum of stable modes in addition to the discrete one. We obtain a unique unstable mode with a characteristic time that is comparable with the characteristic life-time observed for loops. The feasibility of wave-based and flow-based models is examined.
Non-Gaussianity at tree and one-loop levels from vector field perturbations
Valenzuela-Toledo, Cesar A.; Rodriguez, Yeinzon; Lyth, David H.
2009-11-15
We study the spectrum P{sub {zeta}} and bispectrum B{sub {zeta}} of the primordial curvature perturbation {zeta} when the latter is generated by scalar and vector field perturbations. The tree-level and one-loop contributions from vector field perturbations are worked out considering the possibility that the one-loop contributions may be dominant over the tree-level terms [both (either) in P{sub {zeta}} and (or) in B{sub {zeta}}] and vice versa. The level of non-Gaussianity in the bispectrum, f{sub NL}, is calculated and related to the level of statistical anisotropy in the power spectrum, g{sub {zeta}}. For very small amounts of statistical anisotropy in the power spectrum, the level of non-Gaussianity may be very high, in some cases exceeding the current observational limit.
Membrane loop process for separating carbon dioxide for use in gaseous form from flue gas
Wijmans, Johannes G; Baker, Richard W; Merkel, Timothy C
2014-10-07
The invention is a process involving membrane-based gas separation for separating and recovering carbon dioxide emissions from combustion processes in partially concentrated form, and then transporting the carbon dioxide and using or storing it in a confined manner without concentrating it to high purity. The process of the invention involves building up the concentration of carbon dioxide in a gas flow loop between the combustion step and a membrane separation step. A portion of the carbon dioxide-enriched gas can then be withdrawn from this loop and transported, without the need to liquefy the gas or otherwise create a high-purity stream, to a destination where it is used or confined, preferably in an environmentally benign manner.
The Polyakov Loop and its Relation to Static Quark Potentials and Free Energies
Jahn, O; Jahn, Oliver; Philipsen, Owe
2004-01-01
It appears well accepted in the literature that the correlator of Polyakov loops in a finite temperature system decays with the "average" free energy of the static quark-antiquark system, and can be decomposed into singlet and adjoint (or octet for QCD) contributions. By fixing a gauge respecting the transfer matrix, attempts have been made to extract those contributions separately. In this paper we point out that the "average" and "adjoint" channels of Polyakov loop correlators are misconceptions. We show analytically that all channels receive contributions from singlet states only, and give a corrected definition of the singlet free energy. We verify this finding by simulations of the 3d SU(2) pure gauge theory in the zero temperature limit, which allows to cleanly extract the ground state exponents and the non-trivial matrix elements. The latter account for the difference between the channels observed in previous simulations.
Periods and damping rates of fast sausage oscillations in multi-shelled coronal loops
Chen, Shao-Xia; Xia, Li-Dong; Yu, Hui
2015-01-01
Standing sausage modes are important in interpreting quasi-periodic pulsations in the lightcurves of solar flares. Their periods and damping times play an important role in seismologically diagnosing key parameters like the magnetic field strength in regions where flare energy is released. Usually such applications are based on theoretical results neglecting unresolved fine structures in magnetized loops. However, the existence of fine structuring is suggested on both theoretical and observational grounds. Adopting the framework of cold magnetohydrodynamics (MHD), we model coronal loops as magnetized cylinders with a transverse equilibrium density profile comprising a monolithic part and a modulation due to fine structuring in the form of concentric shells. The equation governing the transverse velocity perturbation is solved with an initial-value-problem approach, and the effects of fine structuring on the periods $P$ and damping times $\\tau$ of global, leaky, standing sausage modes are examined. A parameter...
Three-loop HTLpt thermodynamics at finite temperature and isospin chemical potential
Andersen, Jens O; Mustafa, Munshi G; Strickland, Michael
2015-01-01
In a previous paper (JHEP {\\bf 05} (2014) 27), we calculated the three-loop thermodynamic potential of QCD at finite temperature $T$ and quark chemical potentials $\\mu_q$ using the hard-thermal-loop perturbation theory (HTLpt) reorganization of finite temperature and density QCD. The result allows us to study the thermodynamics of QCD at finite temperature and isospin chemical potential $\\mu_I$. We calculate the pressure, energy density, and entropy density, the trace anomaly, and the speed of sound at zero and nonzero $\\mu_I$. The second, fourth, and sixth-order isospin susceptibilities are calculated at zero $\\mu_I$. Our results can be directly compared to lattice QCD without Taylor expansions around $\\mu_q=0$ since QCD has no sign problem at finite isospin chemical potential.
Effective potential for Polyakov loops from a center symmetric effective theory in three dimensions
Dominik Smith
2012-07-04
We present lattice simulations of a center symmetric dimensionally reduced effective field theory for SU(2) Yang Mills which employ thermal Wilson lines and three-dimensional magnetic fields as fundamental degrees of freedom. The action is composed of a gauge invariant kinetic term, spatial gauge fields and a potential for the Wilson line which includes a "fuzzy" bag term to generate non-perturbative fluctuations. The effective potential for the Polyakov loop is extracted from the simulations including all modes of the loop as well as for cooled configuration where the hard modes have been averaged out. The former is found to exhibit a non-analytic contribution while the latter can be described by a mean-field like ansatz with quadratic and quartic terms, plus a Vandermonde potential which depends upon the location within the phase diagram.
Innovative Waste Management in the Mercury Loop of the EURISOL Multi-MW Converter Target
PSI: Jörg Neuhausen, Dorothea Schumann, Rugard Dressler, Susanne Horn, Sabrina Lu?thi, Stephan Heinitz, Suresh ChirikiCERN: Thierry Stora, Martin Eller
The choice of mercury as target material imposes various questions concerning the safe operation of such a system that are related to the physical and chemical properties of the target material itself and the nuclear reaction products produced within the target during its life time of several decades. Therefore, a subtask was created within the EURISOL-DS project that is concerned with studying an innovative waste management for the generated radioactivity by chemical means. Such a study strongly depends on the radioactive inventory and its distribution throughout the target and loop system. Radioactive inventory calculations were performed within task 5 [6]. The distribution of nuclear reaction products and their chemical state that can be expected within the target and loop system is one of the topics covered in this report. Based on the results obtained by theoretical studies as well as laboratory scale experiments, the feasibility of waste reduction using chemical methods, both conventional (e.g. leaching...
Three-point functions in ${\\cal N}=4$ SYM: the hexagon proposal at three loops
Eden, Burkhard
2015-01-01
Basso, Komatsu and Vieira recently proposed an all-loop framework for the computation of three-point functions of single-trace operators of ${\\cal N}=4$ super-Yang-Mills, the "hexagon program". This proposal results in several remarkable predictions, including the three-point function of two protected operators with an unprotected one in the $SU(2)$ and $SL(2)$ sectors. Such predictions consist of an "asymptotic" part---similar in spirit to the asymptotic Bethe Ansatz of Beisert and Staudacher for two-point functions---as well as additional finite-size "wrapping" L\\"uscher-like corrections. The focus of this paper is on such wrapping corrections, which we compute at three-loops in the $SL(2)$ sector. The resulting structure constants perfectly match the ones obtained in the literature from four-point correlators of protected operators.
Homotopy Operators and One-Loop Vacuum Energy at the Tachyon Vacuum
Shoko Inatomi; Isao Kishimoto; Tomohiko Takahashi
2012-01-31
We construct the homotopy operators for the BRST operator in the theory around the identity-based solutions, which are believed to represent the tachyon vacuum in cubic bosonic open string field theory. Using the homotopy operators, we find that the one-loop vacuum energy at the tachyon vacuum is independent of moduli such as interbrane distances, which are included in the BRST operator. We also revisit the cohomology problem, which was solved earlier without the homotopy operators.