40 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Entropy"  
Results: 1 - 24 next
open access

Computer codes used in the calculation of high-temperature thermodynamic properties of sodium

Description: Three computer codes - SODIPROP, NAVAPOR, and NASUPER - were written in order to calculate a self-consistent set of thermodynamic properties for saturated, subcooled, and superheated sodium. These calculations incorporate new critical parameters (temperature, pressure, and density) and recently derived single equations for enthalpy and vapor pressure. The following thermodynamic properties have been calculated in these codes: enthalpy, heat capacity, entropy, vapor pressure, heat of vaporizatio… more
Date: December 1, 1979
Creator: Fink, J.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An entropic approach to the analysis of time series.

Description: Statistical analysis of time series. With compelling arguments we show that the Diffusion Entropy Analysis (DEA) is the only method of the literature of the Science of Complexity that correctly determines the scaling hidden within a time series reflecting a Complex Process. The time series is thought of as a source of fluctuations, and the DEA is based on the Shannon entropy of the diffusion process generated by these fluctuations. All traditional methods of scaling analysis, instead, are base… more
Date: December 2001
Creator: Scafetta, Nicola
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Quantum entanglement of baby universes

Description: We study quantum entanglements of baby universes which appear in non-perturbative corrections to the OSV formula for the entropy of extremal black holes in type IIA string theory compactified on the local Calabi-Yau manifold defined as a rank 2 vector bundle over an arbitrary genus G Riemann surface. This generalizes the result for G=1 in hep-th/0504221. Non-perturbative terms can be organized into a sum over contributions from baby universes, and the total wave-function is their coherent super… more
Date: December 7, 2006
Creator: Essman, Eric P.; Aganagic, Mina; Okuda, Takuya & Ooguri, Hirosi
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Temporal Entropy Generation in the Viscous Layers of Laterally-converging Duct Flows

Description: Since insight into entropy generation is a key to increasing efficiency and thereby reducing fuel consumption and/or waste and -- for wall-bounded flows -- most entropy is generated in the viscous layer, we examine the transient behavior of its dominant contributor there for a non-canonical flow. New measurements in oil flow are presented for the effects of favorable streamwise mean pressure gradients on temporal entropy generation rates and, in the process, on key Reynolds-stress-producing eve… more
Date: December 1, 2008
Creator: McEligot, Donald M.; Brodkey, Robert S. & Eckelmann, Helmut
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Physics of reshock and mixing in single-mode Richtmyer-Meshkov instability

Description: The ninth-order weighted essentially non-oscillatory (WENO) shock-capturing method is used to investigate the physics of reshock and mixing in two-dimensional single-mode Richtmyer-Meshkov instability to late times. The initial conditions and computational domain were adapted from the Mach 1.21 air(acetone)/SF{sub 6} shock tube experiment of Collins and Jacobs [J. Fluid Mech. 464, 113 (2002)]: the growth of the bubble and spike perturbation amplitudes from fifth- and ninth-order WENO simulation… more
Date: December 13, 2006
Creator: Schilling, O; Latini, M & Don, W
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Universal Entanglement Entropy in 2D Conformal Quantum Critical Points

Description: We study the scaling behavior of the entanglement entropy of two dimensional conformal quantum critical systems, i.e. systems with scale invariant wave functions. They include two-dimensional generalized quantum dimer models on bipartite lattices and quantum loop models, as well as the quantum Lifshitz model and related gauge theories. We show that, under quite general conditions, the entanglement entropy of a large and simply connected sub-system of an infinite system with a smooth boundary ha… more
Date: December 5, 2008
Creator: Hsu, Benjamin; Mulligan, Michael; Fradkin, Eduardo & Kim, Eun-Ah
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Physics of supernovae

Description: Presupernova models of massive stars are presented and their explosion by ''delayed neutrino transport'' examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 Msub solar. Carbon deflagration in white dwarfs is discussed as the probable explanation of Type I supernovae and special attention is paid to the physical processes whereby a nuclear flame propagates through d… more
Date: December 13, 1985
Creator: Woosley, S. E. & Weaver, T. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The entropy in supernova explosions

Description: The explosion of a supernova forms because of the collapse to a neutron star. In addition an explosion requires that a region of relatively high entropy be in contact with the neutron star and persisting for a relatively protracted period of time. The high entropy region ensures that the maximum temperature in contact with the neutron star and in hydrostatic equilibrium is less than some maximum. This temperature must be low enough such that neutrino emission cooling is small, otherwise the equ… more
Date: December 6, 1990
Creator: Colgate, S. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The thermodynamic properties of 2-aminobiphenyl (an intermediate in the carbazole/hydrogen reaction network)

Description: Catalytic hydrodenitrogenation (HDN) is a key step in upgrading processes for conversion of heavy petroleum, shale oil, tar sands, and the products of the liquefaction of coal to economically viable products. This research program provides accurate experimental thermochemical and thermophysical properties for key organic nitrogen-containing compounds present in the range of alternative feedstocks, and applies the experimental information to thermodynamic analyses of key HDN reaction networks. T… more
Date: December 1, 1990
Creator: Steele, W. V.; Chirico, R. D.; Knipmeyer, S. E. & Nguyen, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The hard truth

Description: In the Bayesian methodology, the posterior probability combines uncertainty about prior knowledge, and available data about alternative models of reality. The posterior quantifies the degree of certainty one has in inferring the truth in terms of those models. We propose a method to determine the reliability of a specific feature of a Bayesian solution. Our approach is based on an analogy between the negative logarithm of the posterior and a physical potential. This analogy leads to the interpr… more
Date: December 31, 1994
Creator: Hanson, K. M. & Cunningham, C. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Final Report: Deconvolution of Adaptive Optics Images of Titan, Neptune, and Uranus

Description: This project involved images of Titan, Neptune, and Uranus obtained using the 10-meter W.M. Keck II Telescope and its adaptive optics system. An adaptive optics system corrects for turbulence in the Earth's atmosphere by sampling the wavefront and applying a correction based on the distortion measured for a known source within the same isoplanatic patch as the science target (for example, a point source such as a star). Adaptive optics can achieve a 10-fold increase in resolution over that obta… more
Date: December 20, 2002
Creator: Gibbard, S & Marchis, F
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Bridging the Gap in the Chemical Thermodynamic Database for Nuclear Waste Repository: Studies of the Effect of Temperature on Actinide Complexation

Description: Recent results of thermodynamic studies on the complexation of actinides (UO{sub 2}{sup 2+}, NpO{sub 2}{sup +} and Pu{sup 4+}) with F{sup -}, SO{sub 4}{sup 2-} and H{sub 2}PO{sub 4}{sup -}/HPO{sub 4}{sup 2-} at elevated temperatures are reviewed. The data indicate that, for all systems except the 1:1 complexation of Np(V) with HPO{sub 4}{sup 2-}, the complexation of actinides is enhanced by the increase in temperature. The enhancement is primarily due to the increase in the entropy term (T{Delt… more
Date: December 21, 2009
Creator: Rao, Linfeng; Tian, Guoxin; Xia, Yuanxian; Friese, Judah I.; Zanonato, PierLuigi & Di Bernardo, Plinio
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
open access

Equation of state and shock entropy of CaCO/sub 3/

Description: The energy released in a nuclear detonation can vaporize the surrounding medium. If one knows the gaseous equation of state of the medium, it can be used along with estimates of the shock entropy to predict such things as cavity size and seismic effects. We have calculated the equation of state and shock entropy for calcite (CaCO/sub 3/). We formulated the gaseous equation of state for pressures between 1 and 10/sup 6/ bar and temperatures from ambient to 1000 eV using a combination of the TIGE… more
Date: December 14, 1976
Creator: Pasternak, A.; Lee, E. L. & Miller, D. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Black Hole Entropy and Fourie-Mukai Transform

Description: We propose a microscopic CFT description of magnetically charged black holes in IIA compactifications on elliptic fibrations based on the Fourier-Mukai transform. The physical derivation of this model involves a chain of string duality transformations including the 4D/5D black hole correspondence. We compute the asymptotic behavior of the microstate degeneracy in a certain limit of large charges and show that it agrees with the macroscopic entropy formula. An interesting aspect of this setup is… more
Date: December 4, 2006
Creator: Bena, Iosif; /Saclay; Diaconescu, Duiliu-Emanuel; /Rutgers U., Piscataway; Florea, Bogdan & /Stanford U., Phys. Dept. /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A formalism to generate probability distributions for performance-assessment modeling

Description: A formalism is presented for generating probability distributions of parameters used in performance-assessment modeling. The formalism is used when data are either sparse or nonexistent. The appropriate distribution is a function of the known or estimated constraints and is chosen to maximize a quantity known as Shannon`s informational entropy. The formalism is applied to a parameter used in performance-assessment modeling. The functional form of the model that defines the parameter, data from … more
Date: December 31, 1990
Creator: Kaplan, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The thermodynamic properties of 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene

Description: Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene. Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, vibrating-tube densitometry, comparative ebulliometry, inclined-piston gauge manometry, and differential-scanning calorimetry (d.s.c.). Critical properties were estimated for both materials based on the measurement results. Entropies, enthalpies, and… more
Date: December 1, 1992
Creator: Chirico, R. D.; Knipmeyer, S. E.; Nguyen, A.; Smith, N. K. & Steele, W. V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermodynamic property evaluation and magnetic refrigeration cycle analysis for gadolinium gallium garnet

Description: Based on relevant material property data and previous model formulations, a magnetothermodynamic property map for gadolinium gallium garnet (Gd{sub 3}Ga{sub 5}O{sub 12}) was adapted for refrigeration cycle analysis in the temperature range 4-40 K and the magnetic field range 0-6 T. Employing methods similar to those previously developed for other materials and temperature ranges, assessments of limitations and relative performance were made for Carnot, ideal regenerative, and pseudo-constant fi… more
Date: December 1, 1994
Creator: Murphy, R. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

NIF Capsule Sensitivity to Drive Asymmetry

Description: We examine 300 eV ICF capsules with ablators of Ge-doped CH, and consider the 2-D parameter space of ablator thickness and DT-ice thickness. At each point in this parameter space, we optimize the drive for a low entropy implosion. At five points in this parameter space, we run 2-D sensitivity studies with radiation drive asymmetries with both constant and time-varying Legendre coefficient P{sub 2}, P{sub 4}, P{sub 6}, and P{sub 8} to determine how much asymmetry the capsule can tolerate before … more
Date: December 17, 2003
Creator: Haan, S; Suter, L; Pollaine, S; Herrmann, M; Amendt, P & Jones, O
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The thermodynamic properties of 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene. [Tetrahydropyrene and hexahydropyrene]

Description: Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene. Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, vibrating-tube densitometry, comparative ebulliometry, inclined-piston gauge manometry, and differential-scanning calorimetry (d.s.c.). Critical properties were estimated for both materials based on the measurement results. Entropies, enthalpies, and… more
Date: December 1, 1992
Creator: Chirico, R. D.; Knipmeyer, S. E.; Nguyen, A.; Smith, N. K. & Steele, W. V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Acetate at Variable Temperatures (T = 283 - 343 K)

Description: Spectrophotometric titrations were performed to identify the Np(V)/acetate complex and determine the equilibrium constants at variable temperatures (T = 283 - 343 K) and at the ionic strength of 1.05 mol {center_dot} kg{sup -1}. The enthalpy of complexation at corresponding temperatures was determined by microcalorimetric titrations. Results show that the complexation of Np(V) with acetate is weak but strengthened as the temperature is increased. The complexation is endothermic and is entropy-d… more
Date: December 21, 2009
Creator: Rao, Linfeng; Tian, Guoxin; Srinivasan, Thandankorai G.; Zanonato, PierLuigi & Di Bernardo, Plinio
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Merged Source Word Codes for Efficient, High-Speed Entropy Coding

Description: We present our work on fast entropy coders for binary messages utilizing only bit shifts and table lookups. To minimize code table size we limit our code lengths with a novel type of variable-to-variable (VV) length code created from source word merging. We refer to these codes as merged codes. With merged codes it is possible to achieve a desired level of efficiency by adjusting the number of bits read from the source at each step. The most efficient merged codes yield a coder with an ineffici… more
Date: December 5, 2002
Creator: Senecal, J; Joy, K & Duchaineau, M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Estimation of isothermal sections of ternary phase diagrams of lithium containing systems: the Al--Li--Mg system

Description: The method of Kaufman and coworkers is used to provide an estimate of isothermal sections of the Al--Li--Mg system. One starts by calculating the lattice stability of the constituents, the binary interaction coefficients and the binary compound parameters. In the computations, thermodynamic data, when available, were coupled with measured phase diagrams to provide thermodynamically self-consistent liquidus and solidus curves for the binary systems. Standard enthalpies of formation and entropies… more
Date: December 1, 1976
Creator: Saboungi, M. L. & Hsu, C. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen