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Prediction of the entropy production and pressure losses in two-phase flow from the mixing length theory

Description: The case of vertical two-phase flow is examined under the light of the mixing-length theory which was succesfully applied to turbulent flows. The purpose of the analysis is to obtain the pressure distribution along the geothermal wells. The well is modeled as a vertical pipe carrying a fluid of variable density; the density distribution is described by two parameters. The conservation equations are written in boundary layer coordinates and the pressure losses are computed through the entropy pr… more
Date: April 1, 1980
Creator: Maeder, P. F. & Michaelides, E. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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THERMODYNAMICS OF LIGHT EMISSION AND FREE-ENERGY STORAGE INPHOTOSYNTHESIS

Description: A Planck law relationship between absorption and emission spectra is used to compute the fluorescence spectra of some photosynthetic systems from their absorption spectra. Calculated luminescence spectra of purple bacteria agree well but not perfectly with published experimental spectra. Application of the Planck law relation to published activation spectra for Systems I and II of spinach chloroplast permits independent calculation of the luminescence spectra of the two systems; if the luminesc… more
Date: April 1, 1967
Creator: Ross, Robert T. & Calvin, Melvin
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HIGH RESOLUTION FOURIER ANALYSIS WITH AUTO-REGRESSIVE LINEAR PREDICTION

Description: Auto-regressive linear prediction is adapted to double the resolution of Angle-Resolved Photoemission Extended Fine Structure (ARPEFS) Fourier transforms. Even with the optimal taper (weighting function), the commonly used taper-and-transform Fourier method has limited resolution: it assumes the signal is zero beyond the limits of the measurement. By seeking the Fourier spectrum of an infinite extent oscillation consistent with the measurements but otherwise having maximum entropy, the errors c… more
Date: April 1, 1984
Creator: Barton, J. & Shirley, D.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermodynamic properties of 9-methylcarbazole and 1,2,3,4-tetrahydro-9-methylcarbazole

Description: Removal of carbazole and its derivatives from heavy petroleum has proved to be particularly difficult using present technology. Studies have shown carbazole and its alkyl-homologs are the dominant nitrogen-containing components in clarified slurry oils, thereby indicating their low reactivity and/or formation during cat-cracking processes. The results reported here will point the way to the development of new methods of nitrogen removal from carbazole and its derivatives. Measurements leading t… more
Date: April 1, 1991
Creator: Steele, W. V.; Knipmeyer, S. E.; Nguyen, A. & Chirico, R. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermodynamics of high temperature brines

Description: Osmotic and activity coefficient data and enthalpy and heat capacity data for NaCl solutions at saturation pressure of water from 0 to 300{sup 0}C and to saturation composition have been simultaneously fit to a 30 parameter equation. The data are reproduced by the equation, in most cases, to within experimental error. Calculated values of the osmotic coefficient, the activity of water, the activity of NaCl, and the heat capacity, enthalpy and entropy of the solution are given in Tables in 25{su… more
Date: April 1, 1979
Creator: Pitzer, K. S.; Bradley, D. J.; Rogers, P. S. Z. & Peiper, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Local entropy generation analysis of a rotary magnetic heat pump regenerator

Description: The rotary magnetic heat pump has attractive thermodynamic performance but it is strongly influenced by the effectiveness of the regenerator. This study uses local entropy generation analysis to evaluate the regenerator design and to suggest design improvements. The results show that performance of the proposed design is dominated by heat transfer related entropy generation. This suggests that enhancement concepts that improve heat transfer should be considered, even if the enhancement causes a… more
Date: April 1, 1990
Creator: Drost, M. K. & White, M. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Topics in inflationary cosmologies

Description: Several aspects of inflationary cosmologies are discussed. An introduction to the standard hot big bang cosmological model is reviewed, and some of the problems associated with it are presented. A short review of the proposals for solving the cosmological conundrums of the big bang model is presented. Old and the new inflationary scenarios are discussed and shown to be unacceptable. Some alternative scenarios especially those using supersymmetry are reviewed briefly. A study is given of inflati… more
Date: April 1, 1986
Creator: Mahajan, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chemistry of Gaseous Lower Halides of Uranium. Technical Progress Report, 1 September 1979-1 April 1980

Description: The gaseous uranium species UF, UF/sub 2/, UF/sub 3/, and UF/sub 4/ were generated in effusion cell beams by vaporization of UF/sub 4/(s) under reducing conditions, and they were identified and studied by mass spectrometry. From extensive second-law studies of reaction equilibria involving these species and several reaction partners used as reference standards, the individual bond dissociation energies and standard enthalpies of formation of the U-F species were derived. Reaction entropies deri… more
Date: April 15, 1980
Creator: Hildenbrand, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Derived thermodynamic properties for fluid n-T/sub 2/ in the range 75 to 300 K and 2 to 20 kbar

Description: The tritium equation of state, extended from measurements of the lighter hydrogen isotopes, is used to derive thermodynamic properties of tritium fluid. Tabular values are given at rounded kbar pressures and 25/sup 0/K temperature intervals in the range 75 to 300/sup 0/K and 2 to 20 kbar. Included are the isobaric thermal expansion coefficient ..cap alpha../sub p/, the molar heat capacity at constant pressure C/sub p/, adiabatic compressibility coefficient chi/sub s/, heat capacity ratio ..gamm… more
Date: April 1, 1978
Creator: Liebenberg, D.H.; Mills, R.L. & Bronson, J.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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New calorimetric studies of inorganic fluorine compounds. [Silver uranium fluoride, AgUF/sub 6/; cesium fluoroxysulfate, CsSO/sub 4/F]

Description: In this paper, recently determined enthalpies of formation are presented for two fluorides, silver(I) uranium(V) fluoride, AgUF/sub 6/, and cesium fluoroxysulfate, CsSO/sub 4/F. In addition the derivation of entropy is presented for CsSO/sub 4/F.
Date: April 1, 1982
Creator: O'Hare, P. A. G.; Flotow, H. E.; Appleman, E. H. & Malm, J. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Liquid-liquid equilibria in Binary systems: Monte-Carlo simulation for calculating the effect of nonrandom mixing

Description: Monte-Carlo simulations of a lattice model for incompressible monomer/r-mer mixtures are used to obtain accurate results for the configurational energy of mixing. Based on simulation results, the energy of mixing is correlated as a function of temperature and composition using an empirical expression. The configurational Helmholtz energy is obtained upon using the Gibbs-Helmholtz equation with Guggenheim`s athermal entropy of mixing as boundary condition. Since Monte-Carlo simulations give esse… more
Date: April 1, 1992
Creator: Lambert, S. M.; Soane, D. S. & Prausnitz, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Diffusional exchange of isotopes in a metal hydride sphere.

Description: This report describes the Spherical Particle Exchange Model (SPEM), which simulates exchange of one hydrogen isotope by another hydrogen isotope in a spherical metal hydride particle. This is one of the fundamental physical processes during isotope exchange in a bed of spherical metal particles and is thus one of the key components in any comprehensive physics-based model of exchange. There are two important physical processes in the model. One is the entropy of mixing between the two isotopes;… more
Date: April 1, 2011
Creator: Wolfer, Wilhelm G.; Hamilton, John C. & James, Scott Carlton
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Liquid-liquid equilibria in Binary systems: Monte-Carlo simulation for calculating the effect of nonrandom mixing

Description: Monte-Carlo simulations of a lattice model for incompressible monomer/r-mer mixtures are used to obtain accurate results for the configurational energy of mixing. Based on simulation results, the energy of mixing is correlated as a function of temperature and composition using an empirical expression. The configurational Helmholtz energy is obtained upon using the Gibbs-Helmholtz equation with Guggenheim's athermal entropy of mixing as boundary condition. Since Monte-Carlo simulations give esse… more
Date: April 1, 1992
Creator: Lambert, S. M.; Soane, D. S. & Prausnitz, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermodynamic and kinetic aspects of surface acidity. Progress report

Description: Our research in the general area of acid catalysis involves the characterization of solid acidity and the corresponding assessment of catalytic performance of acidic materials. Acid characterization studies are required to provide essential information about the type of acid site (i.e., Lewis versus Bronsted), the strength of the sites, and the mobility of molecules adsorbed on the acid sites. An accurate measure of acid strength is given by the heat of adsorption of a basic probe molecule on t… more
Date: April 1, 1992
Creator: Dumesic, J. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Decoherence, chaos, the quantum and the classical

Description: The key ideas of the environment-induced decoherence approach are reviewed. Application of decoherence to the transition from quantum to classical in open quantum systems with chaotic classical analogs is described. The arrow of time is, in this context, a result of the information loss to the correlations with the environment. The asymptotic rate of entropy production (which is reached quickly, on the dynamical timescale) is independent of the details of the coupling of the quantum system to t… more
Date: April 1, 1994
Creator: Zurek, W. H. & Paz, J. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The thermodynamic properties of thianthrene and phenoxathiin

Description: Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for thianthrene (Chemical Abstracts registry number [92-85-3]) and phenoxathiin (registry number [262-20-41]). 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… more
Date: April 1, 1993
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
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Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

Description: This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are … more
Date: April 23, 2009
Creator: A.A. Schekochihin, S.C. Cowley, W. Dorland, G.W. Hammett, G.G. Howes, E. Quataert, and T. Tatsuno
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Nonlinear Dynamics and Control of Large Arrays of Coupled Oscillators: Application to Fluid-Elastic Problems

Description: Large numbers of fluid elastic structures are part of many power plant systems and vibration of these systems sometimes are responsible for plant shut downs. Earlier research at Cornell in this area had centered on nonlinear dynamics of fluid-elastic systems with low degrees of freedom. The focus of current research is the study of the dynamics of thousands of closely arrayed structures in a cross flow under both fluid and impact forces. This research is relevant to two areas: (1) First, fluid-… more
Date: April 1, 2002
Creator: Moon, Francis C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The thermodynamic properties of thianthrene and phenoxathiin

Description: Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for thianthrene (Chemical Abstracts registry number [92-85-3]) and phenoxathiin (registry number [262-20-41]). 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… more
Date: April 1, 1993
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

Coupled transport processes in semipermeable media

Description: The thermodynamics of irreversible processes (TTIP) is used to derive governing equations and phenomenological equations for transport processes and chemical reactions in water-saturated semipermeable media. TTIP is based on three fundamental postulates. The first postulate, the assumption of local equilibrium, allows the formulation of balance equations for entropy. These equations are the bases for the derivation of governing equations for the thermodynamic variables, temperature, pressure, a… more
Date: April 1, 1990
Creator: Carnahan, C.L. & Jacobsen, J.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Atomistic Simulation of Defect Properties in BCC Tantalum

Description: The fundamental atomic-level properties of point and line defects in bcc Ta have been simulated by means of quantum-based multi-ion interatomic potentials derived from the model generalized pseudopotential theory (MGPT). The potentials have been applied to the calculations of point defect formation and migration energies. The results are then compared with the ab-initio electronic-structure results and experimental data, which in turn provide rigorous validation tests of the MGPT potentials. Ro… more
Date: April 19, 2002
Creator: Yang, L H; Soderlind, P & Moriarty, J A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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