Thermodynamics of the second-stage dissociation of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) in water at different ionic strength and different solvent mixtures

Energy Technology Data Exchange (ETDEWEB)

Taha, Mohamed [Department of Chemistry, Faculty of Science, Cairo University, Beni-Suef Branch, Beni-Suef (Egypt)]. E-mail: mtaha978@yahoo.com; Fazary, Ahmed E. [Department of Chemistry, Faculty of Science, Cairo University, Beni-Suef Branch, Beni-Suef (Egypt)

2005-01-01

The second stage dissociation constant pK{sub 2} of 2-[N-(2-hydroxyethyl)-N-methylaminomethyl]-propenoic acid (HEMPA) has been determined in aqueous solution at different ionic strengths and different temperatures, using pH-metric technique. The thermodynamic quantities ({delta}G{sup 0}, {delta}H{sup 0}, and {delta}S{sup 0}) have been studied and discussed. Evaluation of the effect of organic solvent of the medium on the dissociation processes have also been reported and discussed. The organic solvents used were methanol, dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetone and dioxane. The pK{sub 2} for the ionization in water +10, +20, +30, +40 and +50 wt% dioxane has been determined at five different temperatures from T = (288.15 to 308.15) K at intervals of 5 K. The thermodynamic quantities were calculated. The implications of the results with regard to specific (solute + solvent) interactions (particularly stabilization of zwitterionic species) are also discussed.

Determination of the dissociation constants of some organic complexing agents and stability constants of their uranyl complexes by spectrophotometry

International Nuclear Information System (INIS)

1989-01-01

The dissociation constants of the weak acids derived from quinizarin (1,4-dihydroxy anthraquinone); QMF (2-(2-fury l methyl)), QMPH (2-(2-phenyl methyl)) and QMN (2-(2-naphthyl methyl)) quinizarin were determined. The stability constants of uranyl complexes with the above mentioned ligands were investigated by: 1. The molar-ratio method. 2. Computer program

Estimation of thermodynamic acidity constants of some penicillinase-resistant penicillins.

Science.gov (United States)

Demiralay, Ebru Çubuk; Üstün, Zehra; Daldal, Y Doğan

2014-03-01

In this work, thermodynamic acidity constants (pssKa) of methicillin, oxacillin, nafcillin, cloxacilin, dicloxacillin were determined with reverse phase liquid chromatographic method (RPLC) by taking into account the effect of the activity coefficients in hydro-organic water-acetonitrile binary mixtures. From these values, thermodynamic aqueous acidity constants of these drugs were calculated by different approaches. The linear relationships established between retention factors of the species and the polarity parameter of the mobile phase (ET(N)) was proved to predict accurately retention in LC as a function of the acetonitrile content (38%, 40% and 42%, v/v). Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of Acid Dissociation Constants (pKa) of Bicyclic Thiohydantoin-Pyrrolidine Compounds in 20% Ethanol-Water Hydroorganic Solvent

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Nural, Yahya; Döndaş, H. Ali; Sarı, Hayati; Atabey, Hasan; Belveren, Samet; Gemili, Müge

2014-01-01

The acid dissociation constants of potential bioactive fused ring thiohydantoin-pyrrolidine compounds were determined by potentiometric titration in 20% (v/v) ethanol-water mixed at 25 ± 0.1°C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Proton affinities of potential donor atoms of the ligands were calculated by AM1 and PM3 semiempiric methods. We found, potentiometrically, three different acid dissociation constants for 1a–f. We suggest that these acid dissociation constants are related to the carboxyl, enol, and amino groups. PMID:24799905

Analysis of agonist dissociation constants as assessed by functional antagonism in guinea pig left atria

International Nuclear Information System (INIS)

Molenaar, P.; Malta, E.

1986-01-01

In electrically driven guinea pig left atria, positive inotropic responses to (-)-isoprenaline and the selective beta 1-adrenoceptor agonist RO363 were obtained in the absence and in the presence of the functional antagonists adenosine, carbachol, gallopamil, nifedipine, and Ro 03-7894. Each of the functional antagonists reduced the maximum response to both agonists and produced nonparallel rightward shifts in the cumulative concentration effect curves. For both agonists, dissociation constants (KA) were calculated using the equation described by Furchgott (1966) for irreversible antagonism. For RO363, which is a partial agonist with high agonist activity, the equations outlined for functional interaction by Mackay (1981) were also employed to calculate KA values. The KA values obtained by each method were compared with the dissociation constants (KD) for the two agonists determined from their ability to displace the radioligand (-)-[ 125 I]iodocyanopindolol from beta 1-adrenoceptors in guinea pig left atrial membrane preparations. The estimates of KA varied substantially from KD values. The KD values were taken as more accurate estimates of the true values for the dissociation constants because a high degree of correlation exists between pKD and pD2 values for a number of other beta-adrenoceptor agonists that behave as partial agonists and between pKD and pKB values for a number of beta-adrenoceptor antagonists. Thus, it appears that there are serious limitations in the current theory for using functional antagonism as a means of obtaining agonist dissociation constants

Thermodynamic properties and equilibrium constant of chemical reaction in nanosystem: An theoretical and experimental study

International Nuclear Information System (INIS)

Du, Jianping; Zhao, Ruihua; Xue, Yongqiang

2012-01-01

Highlights: ► There is an obvious influence of the size on thermodynamic properties for the reaction referring nano-reactants. ► Gibbs function, enthalpy, entropy and equilibrium constant are dependent on the reactant size. ► There is an approximate linear relation between them. - Abstract: The theoretical relations of thermodynamic properties, the equilibrium constant and reactant size in nanosystem are described. The effects of size on thermodynamic properties and the equilibrium constant were studied using nanosize zinc oxide and sodium bisulfate solution as a reaction system. The experimental results indicated that the molar Gibbs free energy, the molar enthalpy and the molar entropy of the reaction decrease, but the equilibrium constant increases with decreasing reactant size. Linear trends were observed between the reciprocal of size for nano-reactant and thermodynamic variable, which are consistent with the theoretical relations.

A Unified Kinetics and Equilibrium Experiment: Rate Law, Activation Energy, and Equilibrium Constant for the Dissociation of Ferroin

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Sattar, Simeen

2011-01-01

Tris(1,10-phenanthroline)iron(II) is the basis of a suite of four experiments spanning 5 weeks. Students determine the rate law, activation energy, and equilibrium constant for the dissociation of the complex ion in acid solution and base dissociation constant for phenanthroline. The focus on one chemical system simplifies a daunting set of…

Thermodynamics of ionic migration of simple and complex rare earth salts in mixed alcohol solvents

International Nuclear Information System (INIS)

Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B.

1982-01-01

The influence of the composition of double mixed solvents (water-methanol and methanol-propanol) on thermodynamic characteristics of electrolytic dissociation process-enthalpy and entropy, dissociation constants of chlorides and diphenanthroline chlorides of lanthanum, neodymium, europium and dysprosium, is analyzed. It is shown that when passing from water to methanol, that is, with decrease of dielectric permeability, the endothermicity of electrolytic dissociation process increases

Thermodynamics of ionic migration of simple and complex rare earth salts in mixed alcohol solvents

Energy Technology Data Exchange (ETDEWEB)

Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

1982-04-01

The influence of the composition of double mixed solvents (water-methanol and methanol-propanol) on thermodynamic characteristics of electrolytic dissociation process-enthalpy and entropy, dissociation constants of chlorides and diphenanthroline chlorides of lanthanum, neodymium, europium and dysprosium, is analyzed. It is shown that when passing from water to methanol, that is, with decrease of dielectric permeability, the endothermicity of electrolytic dissociation process increases.

Thermodynamic characteristics of the acid dissociation of dopamine hydrochloride in water-ethanol solutions

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Ledenkov, S. F.; Vandyshev, V. N.; Molchanov, A. S.

2012-06-01

Enthalpies of the interaction of protonated dopamine with a hydroxide ion in water-ethanol mixtures in the concentration range of 0-0.8 EtOH mole fractions are measured calorimetrically. The neutralization process of dopamine hydrochloride is shown to occur endothermally in solvents with an ethanol concentration of ≥0.5 mole fractions. Standard thermodynamic characteristics (Δr H ○, Δr G ○, and Δr S ○) of the first-step acid dissociation of dopamine hydrochloride in solutions are calculated with regard to the autoprotolysis enthalpy of binary solvents. It is found that dissociation enthalpies vary within 9.1-64.8 kJ/mol, depending on the water-ethanol solvent composition.

A New Application for Radioimmunoassay: Measurement of Thermodynamic Constants.

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Angstadt, Carol N.; And Others

1983-01-01

Describes a laboratory experiment in which an equilibrium radioimmunoassay (RIA) is used to estimate thermodynamic parameters such as equilibrium constants. The experiment is simple and inexpensive, and it introduces a technique that is important in the clinical chemistry and research laboratory. Background information, procedures, and results are…

Thermogravimetric analysis and dissociation pressure of caesium trihalides

International Nuclear Information System (INIS)

Harris, G.S.; McKechnie, J.S.

1982-01-01

We have carried out a thermogravimetric study of caesium trihalides to obtain, from the procedural decomposition temperatures, an order of apparent thermal stability which could be compared with the order of thermodynamic stability obtained from vapour pressure measurements. Thermogravimetric analysis could also prove to be a useful method for rapid analysis of metal polyhalides. The thermograms indicated a one-step decomposition for each compound; the procedural decomposition temperatures and percentage weight losses obtained are given. Dissociation pressures were measured and values of equilibrium constant and enthalpy of dissociation were calculated. The results are given. The 'stability' order obtained is discussed. (U.K.)

Determination of Henry's constant, the dissociation constant, and the buffer capacity of the bicarbonate system in ruminal fluid.

Science.gov (United States)

Hille, Katharina T; Hetz, Stefan K; Rosendahl, Julia; Braun, Hannah-Sophie; Pieper, Robert; Stumpff, Friederike

2016-01-01

Despite the clinical importance of ruminal acidosis, ruminal buffering continues to be poorly understood. In particular, the constants for the dissociation of H2CO3 and the solubility of CO2 (Henry's constant) have never been stringently determined for ruminal fluid. The pH was measured in parallel directly in the rumen and the reticulum in vivo, and in samples obtained via aspiration from 10 fistulated cows on hay- or concentrate-based diets. The equilibrium constants of the bicarbonate system were measured at 38°C both using the Astrup technique and a newly developed method with titration at 2 levels of partial pressure of CO2 (pCO2; 4.75 and 94.98 kPa), yielding mean values of 0.234 ± 0.005 mmol ∙ L(-1) ∙ kPa(-1) and 6.11 ± 0.02 for Henry's constant and the dissociation constant, respectively (n/n = 31/10). Both reticular pH and the pH of samples measured after removal were more alkalic than those measured in vivo in the rumen (by ΔpH = 0.87 ± 0.04 and 0.26 ± 0.04). The amount of acid or base required to shift the pH of ruminal samples to 6.4 or 5.8 (base excess) differed between the 2 feeding groups. Experimental results are compared with the mathematical predictions of an open 2-buffer Henderson-Hasselbalch equilibrium model. Because pCO2 has pronounced effects on ruminal pH and can decrease rapidly in samples removed from the rumen, introduction of a generally accepted protocol for determining the acid-base status of ruminal fluid with standard levels of pCO2 and measurement of base excess in addition to pH should be considered. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Constant curvature black holes in Einstein AdS gravity: Euclidean action and thermodynamics

Science.gov (United States)

Guilleminot, Pablo; Olea, Rodrigo; Petrov, Alexander N.

2018-03-01

We compute the Euclidean action for constant curvature black holes (CCBHs), as an attempt to associate thermodynamic quantities to these solutions of Einstein anti-de Sitter (AdS) gravity. CCBHs are gravitational configurations obtained by identifications along isometries of a D -dimensional globally AdS space, such that the Riemann tensor remains constant. Here, these solutions are interpreted as extended objects, which contain a (D -2 )-dimensional de-Sitter brane as a subspace. Nevertheless, the computation of the free energy for these solutions shows that they do not obey standard thermodynamic relations.

Semiclassical Calculation of Reaction Rate Constants for Homolytical Dissociations

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Cardelino, Beatriz H.

2002-01-01

There is growing interest in extending organometallic chemical vapor deposition (OMCVD) to III-V materials that exhibit large thermal decomposition at their optimum growth temperature, such as indium nitride. The group III nitrides are candidate materials for light-emitting diodes and semiconductor lasers operating into the blue and ultraviolet regions. To overcome decomposition of the deposited compound, the reaction must be conducted at high pressures, which causes problems of uniformity. Microgravity may provide the venue for maintaining conditions of laminar flow under high pressure. Since the selection of optimized parameters becomes crucial when performing experiments in microgravity, efforts are presently geared to the development of computational OMCVD models that will couple the reactor fluid dynamics with its chemical kinetics. In the present study, we developed a method to calculate reaction rate constants for the homolytic dissociation of III-V compounds for modeling OMCVD. The method is validated by comparing calculations with experimental reaction rate constants.

Synthesis and Determination of Acid Dissociation Constants in Dimethyl Sulfoxide–Water Hydroorganic Solvent of 5,5-Diphenylpyrrolidine N-Aroylthiourea Derivatives

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Yahya Nural

2017-08-01

Full Text Available Novel 5,5-diphenylpyrrolidineN-aroylthioureas, containing 4-methylbenzoyl, 2-chlorobenzoyl,2,4-dichlorobenzoyl, and2-naphthoyl, were synthesized and their structural analysis was performed using 1H nuclear magnetic resonance (NMR, 13C NMR, Fourier transform infrared spectroscopy, mass spectrometry (MS, and high-resolution MS (HRMS techniques. The acid dissociation constants of the 5,5-diphenylpyrrolidineN-aroylthiourea derivative compounds were determined using Hyperquad computer program for data obtained using potentiometric titration method in 25% (v/v dimethyl sulfoxide–water hydroorganic solvent in the presence of 0.1 mol×L-1 ionic strength of NaCl and in the acidic medium at 25±0.1°C, using sodium hydroxide base as a titrant. Two acid dissociation constants were obtained for 3a, 3b, and 3d, and it was suggested that they were related to N-H and enol groups. Furthermore, three acid dissociation constants obtained for 3a indicated that they were related to N-H, enthiol, and enol groups, and four acid dissociation constants obtained for 3c suggested that they were related to N-H, enthiol, enol, and carboxyl groups.

Increased precision for analysis of protein-ligand dissociation constants determined from chemical shift titrations

Energy Technology Data Exchange (ETDEWEB)

Markin, Craig J.; Spyracopoulos, Leo, E-mail: leo.spyracopoulos@ualberta.ca [University of Alberta, Department of Biochemistry (Canada)

2012-06-15

NMR is ideally suited for the analysis of protein-protein and protein ligand interactions with dissociation constants ranging from {approx}2 {mu}M to {approx}1 mM, and with kinetics in the fast exchange regime on the NMR timescale. For the determination of dissociation constants (K{sub D}) of 1:1 protein-protein or protein-ligand interactions using NMR, the protein and ligand concentrations must necessarily be similar in magnitude to the K{sub D}, and nonlinear least squares analysis of chemical shift changes as a function of ligand concentration is employed to determine estimates for the parameters K{sub D} and the maximum chemical shift change ({Delta}{delta}{sub max}). During a typical NMR titration, the initial protein concentration, [P{sub 0}], is held nearly constant. For this condition, to determine the most accurate parameters for K{sub D} and {Delta}{delta}{sub max} from nonlinear least squares analyses requires initial protein concentrations that are {approx}0.5 Multiplication-Sign K{sub D}, and a maximum concentration for the ligand, or titrant, of {approx}10 Multiplication-Sign [P{sub 0}]. From a practical standpoint, these requirements are often difficult to achieve. Using Monte Carlo simulations, we demonstrate that co-variation of the ligand and protein concentrations during a titration leads to an increase in the precision of the fitted K{sub D} and {Delta}{delta}{sub max} values when [P{sub 0}] > K{sub D}. Importantly, judicious choice of protein and ligand concentrations for a given NMR titration, combined with nonlinear least squares analyses using two independent variables (ligand and protein concentrations) and two parameters (K{sub D} and {Delta}{delta}{sub max}) is a straightforward approach to increasing the accuracy of measured dissociation constants for 1:1 protein-ligand interactions.

Thermodynamics of acid-base dissociation of several cathinones and 1-phenylethylamine, studied by an accurate capillary electrophoresis method free from the Joule heating impact.

Science.gov (United States)

Nowak, Paweł Mateusz; Woźniakiewicz, Michał; Mitoraj, Mariusz; Sagan, Filip; Kościelniak, Paweł

2018-03-02

Capillary electrophoresis is often used to the determination of the acid-base dissociation/deprotonation constant (pK a ), and the more advanced thermodynamic quantities describing this process (ΔH°, -TΔS°). Remarkably, it is commonly overlooked that due to insufficient dissipation of Joule heating the accuracy of parameters determined using a standard approach may be questionable. In this work we show an effective method allowing to enhance reliability of these parameters, and to estimate the magnitude of errors. It relies on finding a relationship between electrophoretic mobility and actual temperature, and performing pK a determination with the corrected mobility values. It has been employed to accurately examine the thermodynamics of acid-base dissociation of several amine compounds - known for their strong dependency of pK a on temperature: six cathinones (2-methylmethcathinone, 3-methylmethcathinone, 4-methylmethcathinone, α-pyrrolidinovalerophenone, methylenedioxypyrovalerone, and ephedrone); and structurally similar 1-phenylethylamine. The average pK a error caused by Joule heating noted at 25 °C was relatively small - 0.04-0.05 pH unit, however, a more significant inaccuracy was observed in the enthalpic and, in particular, entropic terms. An alternative correction method has also been proposed, simpler and faster, but not such effective in correcting ΔH°/-TΔS° terms. The corrected thermodynamic data have been interpreted with the aid of theoretical calculations, on a ground of the enthalpy-entropy relationships and the most probable structural effects accounting for them. Finally, we have demonstrated that the thermal dependencies of electrophoretic mobility, modelled during the correction procedure, may be directly used to find optimal temperature providing a maximal separation efficiency. Copyright © 2018 Elsevier B.V. All rights reserved.

The dissociation mechanism and thermodynamic properties of HCl(aq) in hydrothermal fluids (to 700 °C, 60 kbar) by ab initio molecular dynamics simulations

Science.gov (United States)

Mei, Yuan; Liu, Weihua; Brugger, Joël; Sherman, David M.; Gale, Julian D.

2018-04-01

studies, and between different studies, becomes smaller as the degree of HCl association increases. The MD simulations and available experimental studies show consistent results at hydrothermal conditions (300-700 °C, up to 5 kbar). The new thermodynamic properties based on the MD results provide an independent check of the dissociation constants for HCl(aq), and the first dataset on HCl dissociation in high P-T fluids (up to 60 kbar, 700 °C) beyond available experimental conditions. Our results will enable prediction of the role of HCl in controlling element mobility in deep earth hydrothermal systems, including fluids associated with ultra-high pressure metasomatism in subduction zones.

Determination of acid dissociation constants of triazole fungicides by pressure assisted capillary electrophoresis

Czech Academy of Sciences Publication Activity Database

Konášová, Renáta; Jaklová Dytrtová, Jana; Kašička, Václav

2015-01-01

Roč. 1408, Aug 21 (2015), s. 243-249 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-17224S; GA ČR GP13-21409P Institutional support: RVO:61388963 Keywords : triazole fungicides * acid dissociation constant * pK(a) * capillary electrophoresis * ionic mobility Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.926, year: 2015

Gauss-Bonnet coupling constant as a free thermodynamical variable and the associated criticality

International Nuclear Information System (INIS)

Xu, Wei; Xu, Hao; Zhao, Liu

2014-01-01

The thermodynamic phase space of Gauss-Bonnet (GB) AdS black holes is extended, taking the inverse of the GB coupling constant as a new thermodynamic pressure P GB . We studied the critical behavior associated with P GB in the extended thermodynamic phase space at fixed cosmological constant and electric charge. The result shows that when the black holes are neutral, the associated critical points can only exist in five dimensional GB-AdS black holes with spherical topology, and the corresponding critical exponents are identical to those for the Van der Waals system. For charged GB-AdS black holes, it is shown that there can be only one critical point in five dimensions (for black holes with either spherical or hyperbolic topologies), which also requires the electric charge to be bounded within some appropriate range; while in d < 5 dimensions, there can be up to two different critical points at the same electric charge, and the phase transition can occur only at temperatures which are not in between the two critical values. (orig.)

Photometric determination of the composition and dissociation constants of niobium (5) citrate complexes

International Nuclear Information System (INIS)

Grigor'eva, V.V.; Golubeva, I.V.

1979-01-01

Niobium (5) citrate complexes in aqueous solution (pH 1-6) are investigated. To determine the complexes composition the metal-indicator method has been applied. Experimental data have been treated by the method of equilibrium shift using somewhat changed variant of the metal-indicator method. The complex ion charge in the solution has been determined by the ion-exchange method. Dissociation constants of citrate complexes have been determined photometrically

Measurements of some basic constants of 68Ga(BAT-TECH) as an imaging agent

International Nuclear Information System (INIS)

Chen Huawei; Liu Boli

1994-01-01

The kinetic properties of a new myocardial imaging agent 68 Ga(BAT-TECH) are investigated and its thermodynamic constants are measured. The results are as follows: Citrate→BAT-TECH exchange reaction order is second-order; reaction rate k = 0.50 l/mol·s; activation energy E a = 56.6 kJ/mol; the stability constant of 68 Ga(BAT-TECH) lgβ = 14.9; the acid dissociation constants of BAT-TECH pK 1 = 4.62, pK 2 = 7.68, pK-3 = 8.68, pK 4 = 11.2

A procedure to find thermodynamic equilibrium constants for CO2 and CH4 adsorption on activated carbon.

Science.gov (United States)

Trinh, T T; van Erp, T S; Bedeaux, D; Kjelstrup, S; Grande, C A

2015-03-28

Thermodynamic equilibrium for adsorption means that the chemical potential of gas and adsorbed phase are equal. A precise knowledge of the chemical potential is, however, often lacking, because the activity coefficient of the adsorbate is not known. Adsorption isotherms are therefore commonly fitted to ideal models such as the Langmuir, Sips or Henry models. We propose here a new procedure to find the activity coefficient and the equilibrium constant for adsorption which uses the thermodynamic factor. Instead of fitting the data to a model, we calculate the thermodynamic factor and use this to find first the activity coefficient. We show, using published molecular simulation data, how this procedure gives the thermodynamic equilibrium constant and enthalpies of adsorption for CO2(g) on graphite. We also use published experimental data to find similar thermodynamic properties of CO2(g) and of CH4(g) adsorbed on activated carbon. The procedure gives a higher accuracy in the determination of enthalpies of adsorption than ideal models do.

A consistent set of thermodynamic constants for americium (III) species with hydroxyl and carbonate

International Nuclear Information System (INIS)

Kerrisk, J.F.; Silva, R.J.

1986-01-01

A consistent set of thermodynamic constants for aqueous species, and compounds of Am(III) with hydroxyl and carbonate ligands has been developed. The procedure used to develop these constants involved establishing a value for one formation constant at a time in a sequential order, starting with the hydrolysis products and hydroxide solids, and then proceeding to carbonate species. The EQ3NR chemical-equilibrium model was used to test the constants developed. These constants are consistent with most of the experimental data that form their basis; however, considerable uncertainty still exists in some aspects of the Am(III) data

Dissociation kinetics of acyclic and macrocyclic polyaminopolycarboxylate complexes of yttrium

International Nuclear Information System (INIS)

Pathak, P.N.; Manchanda, V.K.

2000-01-01

Dissociation kinetics of Y III complexes of a linear as well as two macrocyclic polyaminopolycarboxylates, ethylenediamine diacetic acid (EDDA), 1,7-diaza-4,10,13-trioxacyclopentadecane-N,N'-diacetic acid (K21DA) and 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-diacetic acid (K22DA) have been studied at a constant ionic strength (0.1 M) under varying (H + ) and temperatures. Cu II ion acts as the scavenger of the free ligand. Dissociation rate of Y III -K21DA is insensitive to Cu II and acetate (used as buffer anion) concentrations. Kinetic stability of the three complexes follow the order : Y III -K22DA>Y III -K21DA>Y III -EDDA. Enthalpies of activation for K21DA and K22DA complexes of Y III are also evaluated. Thermodynamic stability constant (log K) for Y III -K22DA complex is 10.81 ± 0.04. (author)

Force and Stress along Simulated Dissociation Pathways of Cucurbituril-Guest Systems.

Science.gov (United States)

Velez-Vega, Camilo; Gilson, Michael K

2012-03-13

The field of host-guest chemistry provides computationally tractable yet informative model systems for biomolecular recognition. We applied molecular dynamics simulations to study the forces and mechanical stresses associated with forced dissociation of aqueous cucurbituril-guest complexes with high binding affinities. First, the unbinding transitions were modeled with constant velocity pulling (steered dynamics) and a soft spring constant, to model atomic force microscopy (AFM) experiments. The computed length-force profiles yield rupture forces in good agreement with available measurements. We also used steered dynamics with high spring constants to generate paths characterized by a tight control over the specified pulling distance; these paths were then equilibrated via umbrella sampling simulations and used to compute time-averaged mechanical stresses along the dissociation pathways. The stress calculations proved to be informative regarding the key interactions determining the length-force profiles and rupture forces. In particular, the unbinding transition of one complex is found to be a stepwise process, which is initially dominated by electrostatic interactions between the guest's ammoniums and the host's carbonyl groups, and subsequently limited by the extraction of the guest's bulky bicyclooctane moiety; the latter step requires some bond stretching at the cucurbituril's extraction portal. Conversely, the dissociation of a second complex with a more slender guest is mainly driven by successive electrostatic interactions between the different guest's ammoniums and the host's carbonyl groups. The calculations also provide information on the origins of thermodynamic irreversibilities in these forced dissociation processes.

Clathrate hydrate dissociation conditions of refrigerants R404A, R406A, R408A and R427A: Experimental measurements and thermodynamic modeling

International Nuclear Information System (INIS)

Hashemi, Hamed; Babaee, Saeedeh; Mohammadi, Amir H.; Naidoo, Paramespri; Ramjugernath, Deresh

2015-01-01

Highlights: • The application of refrigerant hydrates in cold storage systems is investigated. • Hydrate dissociation conditions of various refrigerants have been measured. • A correlative thermodynamic model was applied to the data. • Enthalpy of dissociation for the refrigerants studied calculated. • Experimental measurements performed over a wide range of pressures. - Abstract: Clathrate hydrate dissociation conditions were measured for four “alternative” refrigerants, viz. R404A, R406A, R408A and R427A. The experimental measurements were performed within the pressure range of (0.079 to 9.995) MPa and temperatures ranging from (272.7 to 288.7) K. An isochoric pressure-search method was used to perform the measurements. A thermodynamic model based on the van der Waals–Platteeuw (vdW–P) model was applied for the prediction of the dissociation conditions which were compared to the experimental measurements. The fluid phase was modeled using the MHV2 G E -EoS mixing rule along with the UNIFAC (original) activity model. The van der Waals–Platteeuw (vdW–P) model was used for the modeling of the hydrate phase. There was reasonable agreement between the experimental and predicted values

Determination of dissociation constants of compounds with potential cognition enhancing activity by capillary zone electrophoresis

Czech Academy of Sciences Publication Activity Database

Lišková, A.; Křivánková, Ludmila

2005-01-01

Roč. 26, č. 23 (2005), s. 4429-4439 ISSN 0173-0835 R&D Projects: GA ČR GA203/05/2106; GA AV ČR IAA4031401 Institutional research plan: CEZ:AV0Z40310501 Keywords : Capillary zone electrophoresis * dissociation constants * potential nootropics Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.850, year: 2005

Spectroscopic determination of ionization constants of quinoline and 3-aminoquinoline at different temperature

International Nuclear Information System (INIS)

Indhar, H.A.B.

2000-01-01

Quinoline and its derivative are chemically and biologically important heterocylic compounds. Its ionization constant (pK/sub a/ values have been previously determined only at 18 or 20 deg. C. We have enhanced this work at different temperatures from 20-50 deg. C at the interval of 5 deg. C. The dissociation constants (pk/sub a/s), and Gibb's free energies of quinoline and 3-aminoquinoline have been determined by UV-Spectrophotometer (lambda 2) equipped with a temperature control of - + 0.1 deg. C at temperatures ranging from 20-50 deg. C in water. The experimental data have been used for the determination of thermodynamic ionization constants (pk /sub a //sup t/) sub t/, concentration ionization constants (pK/sub a//sup M/) and Gibbs's free energy values of pK/sub a/sup M/. The ionization constant values decrease with increase of temperature. The significance of relative magnitudes of the values is discussed and some useful generalization are obtained. The curves are parabolic. A computer program in GW-BASIC calculates the values of dissociation constants. From the pK/sub a/ values, Gibb's free energies are compared and discussed. (author)

Comment on “Recent progress in thermodynamics of radiation——exergy of radiation,effective temperature of photon and entropy constant of photon”

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

Chen et al.proposed the concepts of effective temperature of photon and entropy constant of photon in a recent paper [Chen Z S,Mo S P,Hu P.Recent progress in thermodynamics of radiation―exergy of radiation,effective temperature of photon and entropy constant of photon.Sci China Ser E-Tech Sci,2008,51(8):1096―1109] by enduing a single photon with macroscale thermodynamic parameters such as exergy and entropy.This paper argues that applying these concepts and their inferences to macro-scale thermodynamic system will lead to the results which conflict with macroscale thermodynamic laws.This means that the concepts of effective temperature of photon and entropy constant of photon are not correct.

Microsolvated Model for the Kinetics and Thermodynamics of Glycosidic Bond Dissociative Cleavage of Nucleoside D4G.

Science.gov (United States)

Jiang, Yang; Xue, Ying; Zeng, Yi

2018-02-15

Using the microsolvated model that involves explicit water molecules and implicit solvent in the optimization, two proposed dissociative hydrolysis mechanisms of 2',3'-didehydro-2',3'-dideoxyguanosine (d4G) have been first investigated by means of M06-2X(CPCM, water)/6-31++G(d,p) method. The glycosidic bond dissociation for the generation of the oxacarbenium ion intermediate is the rate-determining step (RDS). The subsequent nucleophilic water attack from different side of the oxacarbenium ion intermediate gives either the α-product [(2S,5S)-5-(hydroxymethyl)-2,5-dihydrofuran-2-ol] or β-product [(2R,5S)-5-(hydroxymethyl)-2,5-dihydrofuran-2-ol] and is thus referred to as α-path (inversion) and β-path (retention). Two to five explicit water molecules (n = 2-5) are considered in the microsolvated model, and n = 3 or 4 is the smallest model capable of minimizing the activation energy for α-path and β-path, respectively. Our theoretical results suggest that α-path (n = 3) is more kinetically favorable with lower free energy barrier (RDS) of 27.7 kcal mol -1 , in contrast to that of 30.7 kcal mol -1 for the β-path (n = 4). The kinetic preference of the α-path is rationalized by NBO analysis. Whereas thte β-path is more thermodynamically favorable over the α-path, where the formation of β-product and α-product are exergonic and endergonic, respectively, providing theoretical support for the experimental observation that the β-cleavage product was the major one after sufficient reaction time. Comparisons of d4G with analogous cyclo-d4G and dG from kinetic free energy barriers and thermodynamic heterolytic dissociation energies were also carried out. Our kinetic and thermodynamic results manifest that the order of glycosidic bond stability should be d4G < cyclo-d4G < dG, which agrees well with the reported experimental stability order of d4G compounds and analogues and gives further understanding on the influence of 6-cyclopropylamino and unsaturated ribose to

Acid dissociation constant and apparent nucleophilicity of lysine-501 of the alpha-polypeptide of sodium and potassium ion activated adenosinetriphosphatase

International Nuclear Information System (INIS)

Xu, K.Y.

1989-01-01

A combination of competitive labeling with [ 3 H]acetic anhydride and immunoaffinity chromatography is described that permits the assignment of the acid dissociation constant and the absolute nucleophilicity of individual lysines in a native enzyme. The acid dissociation constant of lysine-501 of the alpha-polypeptide in native (Na+ + K+)-ATPase was determined. This lysine had a normal pKa of 10.4. The rate constant for the reaction of the free base of lysine-501 with acetic anhydride at 10 degrees C is 400 M-1 s-1. This value is only 30% that for a fully accessible lysine in a protein. The lower than normal apparent nucleophilicity suggests that lysine-501 is hindered from reacting with its intrinsic nucleophilicity by the tertiary structure of the enzyme and is consistent with its location within a pocket that forms the active site upon the surface of the native protein

Thermodynamic and kinetic characterization of hydroxyethylamine β-secretase-1 inhibitors

Energy Technology Data Exchange (ETDEWEB)

Mondal, Kalyani; Regnstrom, Karin; Morishige, Winse; Barbour, Robin; Probst, Gary; Xu, Ying-Zi; Artis, Dean R.; Yao, Nanhua; Beroza, Paul; Bova, Michael P., E-mail: mpbova2001@yahoo.com

2013-11-15

Highlights: •Kinetic and thermodynamic characterization of 10 hydroxyethylamine BACE-1 inhibitors. •Equilibrium binding of inhibitors was enthalpy driven for BACE-1. •Negative entropy of binding was observed towards BACE-1, but not Cathepsin-D. •Structural analysis demonstrates ligand binding induces a major conformational change. •Structural analysis and SPR analysis corroborate induced fit and negative entropy of binding. -- Abstract: Alzheimer’s disease (AD) is a devastating neurodegenerative disease affecting millions of people. β-Secretase-1 (BACE-1), an enzyme involved in the processing of the amyloid precursor protein (APP) to form Aβ, is a well validated target for AD. Herein, the authors characterize 10 randomly selected hydroxyethylamine (HEA) BACE-1 inhibitors in terms of their association and dissociation rate constants and thermodynamics of binding using surface plasmon resonance (SPR). Rate constants of association (k{sub a}) measured at 25 °C ranged from a low of 2.42 × 10{sup 4} M{sup −1} s{sup −1} to the highest value of 8.3 × 10{sup 5} M{sup −1} s{sup −1}. Rate constants of dissociation (k{sub d}) ranged from 1.09 × 10{sup −4} s{sup −1} (corresponding to a residence time of close to three hours), to the fastest of 0.028 s{sup −1}. Three compounds were selected for further thermodynamic analysis where it was shown that equilibrium binding was enthalpy driven while unfavorable entropy of binding was observed. Structural analysis revealed that upon ligand binding, the BACE-1flap folds down over the bound ligand causing an induced fit. The maximal difference between alpha carbon positions in the open and closed conformations of the flap was over 5 Å. Thus the negative entropy of binding determined using SPR analysis was consistent with an induced fit observed by structural analysis.

Influence of a solvent on thermodynamics of electrolytic dissociation of simple and complex rare earth salts

Energy Technology Data Exchange (ETDEWEB)

Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

1982-03-01

Influence of the double mixed solvent on thermodynamic characteristics of ionic migration of lanthanum, neodymium, europium and dysprosium chlorides as well as their phenanthroline complexes is considered. Decrease of lambdasub(c) of simple and complex rare earth salts in the lanthanum, neodymium-europium-dysprosium series as explained by increase of solvation degree, associated with lanthanum compression. It is shown that increase of methanol or propanol content results in exothermicity decrease of the ionic migration process. The temperature constituents of enthalpy and entropy of dissociation of the simple and complex rare earth salts are presented.

Thermodynamics of ion binding to phosphatidic acid bilayers. Titration calorimetry of the heat of dissociation of DMPA.

Science.gov (United States)

Blume, A; Tuchtenhagen, J

1992-05-19

The heat of dissociation of the second proton of 1,2-dimyristoylphosphatidic acid (DMPA) was studied as a function of temperature using titration calorimetry. The dissociation of the second proton of DMPA was induced by addition of NaOH. From the calorimetric titration experiment, the intrinsic pK0 for the dissociation reaction could be determined by applying the Gouy-Chapman theory. pK0 decreases with temperature from ca. 6.2 at 11 degrees C to 5.4 at 54 degrees C. From the total heat of reaction, the dissociation enthalpy, delta Hdiss, was determined by subtracting the heat of neutralization of water and the heat of dilution of NaOH. In the temperature range between 2 and 23 degrees C, delta Hdiss is endothermic with an average value of ca. 2.5 kcal.mol-1 and shows no clear-cut temperature dependence. In the temperature range between 23 and 52 degrees C, delta Hdiss calculated after subtraction of the heat of neutralization and dilution is not the true dissociation enthalpy but includes contributions from the phase transition enthalpy, delta Htrans, as the pH jump induces a transition from the gel to the liquid-crystalline phase. The delta Cp for the reaction enthalpy observed in this temperature range is positive. Above 53 degrees C, the pH jump induces again only the dissociation of the second proton, and the bilayers stay in the liquid-crystalline phase. In this temperature range, delta Hdiss seems to decrease with temperature. The thermodynamic data from titration calorimetry and differential scanning calorimetry as a function of pH can be combined to construct a complete enthalpy-temperature diagram of DMPA in its two ionization states.

The dissociation constants of the cytostatic bosutinib by nonlinear least-squares regression of multiwavelength spectrophotometric and potentiometric pH-titration data.

Science.gov (United States)

Meloun, Milan; Nečasová, Veronika; Javůrek, Milan; Pekárek, Tomáš

2016-02-20

Potentiometric and spectrophotometric pH-titration of the multiprotic cytostatics bosutinib for dissociation constants determination were compared. Bosutinib treats patients with positive chronic myeloid leukemia. Bosutinib exhibits four protonatable sites in a pH range from 2 to 11, where two pK are well separated (ΔpK>3), while the other two are near dissociation constants. In the neutral medium, bosutinib occurs in the slightly water soluble form LH that can be protonated to the soluble cation LH4(3+). The molecule LH can be dissociated to still difficultly soluble anion L(-). The set of spectra upon pH from 2 to 11 in the 239.3-375.0nm was divided into two absorption bands: the first one from 239.3 to 290.5nm and the second from 312.3 to 375.0nm, which differ in sensitivity of chromophores to a pH change. Estimates of pK of the entire set of spectra were compared with those of both absorption bands. Due to limited solubility of bosutinib the protonation in a mixed aqueous-methanolic medium was studied. In low methanol content of 3-6% three dissociation constants can be reliably determined with SPECFIT/32 and SQUAD(84) and after extrapolation to zero content of methanol they lead to pKc1=3.43(12), pKc2=4.54(10), pKc3=7.56(07) and pKc4=11.04(05) at 25°C and pKc1=3.44(06), pKc2=5.03(08) pKc3=7.33(05) and pKc4=10.92(06) at 37°C. With an increasing content of methanol in solvent the dissociation of bosutinib is suppressed and the percentage of LH3(2+) decreases and LH prevails. From the potentiometric pH-titration at 25°C the concentration dissociation constants were estimated with ESAB pKc1=3.51(02), pKc2=4.37(02), pKc3=7.97(02) and pKc4=11.05(03) and with HYPERQUAD: pKc1=3.29(12), pKc2=4.24(10), pKc3=7.95(07) and pKc4=11.29(05). Copyright © 2015 Elsevier B.V. All rights reserved.

Thermodynamics of strange quark matter with the density-dependent bag constant

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

The thermodynamics of strange quark matter with density dependent bag constant are studied self-consistently in the framework of the general ensemble theory and the MIT bag model.In our treatment,an additional term is found in the expression of pressure.With the additional term,the zero pressure locates exactly at the lowest energy state,indicating that our treatment is a self-consistently thermodynamic treatment.The self-consistent equations of state of strange quark matter in both the normal and color-flavor-locked phase are derived.They are both softer than the inconsistent ones.Strange stars in both the normal and color-flavor locked phase have smaller masses and radii in our treatment.It is also interesting to find that the energy density at a star surface in our treatment is much higher than that in the inconsistent treatment for both phases.Consequently,the surface properties and the corresponding observational properties of strange stars in our treatment are different from those in the inconsistent treatment.

Thermodynamics of strange quark matter with the density-dependent bag constant

Institute of Scientific and Technical Information of China (English)

ZHU MingFeng; LIU GuangZhou; YU Zi; XU Yan; SONG WenTao

2009-01-01

The thermodynamics of strange quark matter with density dependent bag constant are studied selfconsistently in the framework of the general ensemble theory and the MIT bag model.In our treatment,an additional term Is found in the expression of pressure.With the additional term,the zero pressure locates exactly at the lowest energy state,Indicating that our treatment is a self-consistently thermodynamic treatment.The self-consistent equations of state of strange quark matter in both the normal and color-flavor-locked phase are derived.They are both softer than the inconsistent ones.Strange stars in both the normal and color-flavor locked phase have smaller masses and radii in our treatment.It is also interesting to find that the energy density at a star surface in our treatment is much higher than that In the inconsistent treatment for both phases.Consequently,the surface properties and the corresponding observational properties of strange stars in our treatment are different from those in the inconsistent treatment.

Equilibrium dissociation pressures of lithium hydride and lithium deuteride

International Nuclear Information System (INIS)

Smith, H.M.; Webb, R.E.

1977-12-01

The equilibrium dissociation pressures of plateau composition lithium hydride and lithium deuteride have been measured from 450 to 750 0 C. These data were used to derive the relationship of dissociation pressure with temperature over this range and to calculate several thermodynamic properties of these materials. Thermodynamic properties determined included the enthalpy, entropy, and free energy of formation; the enthalpy and entropy of fusion; and the melting points

Potentiometric and Thermodynamic Studies of Some Schiff-Base Derivatives of 4-Aminoantipyrine and Their Metal Complexes

Directory of Open Access Journals (Sweden)

A. A. El-Bindary

2013-01-01

Full Text Available The proton-ligand dissociation constant of 4-(4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-phenol ( and 4-(4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-benzoic acid ( and metal-ligand stability constants of their complexes with metal ions (Mn2+, Co2+, Ni2+, and Cu2+ have been determined potentiometrically in 0.1 mol·dm−3 KCl and 10% (by volume ethanol-water mixture and at 298, 308, and 318 K. The stability constants of the formed complexes increase in the order Mn2+, Co2+, Ni2+, and Cu2+. The effect of temperature was studied, and the corresponding thermodynamic parameters (, , and were derived and discussed. The dissociation process is nonspontaneous, endothermic, and entropically unfavourable. The formation of the metal complexes has been found to be spontaneous, endothermic, and entropically favourable.

Ionization and thermodynamic constants of 6-methylquinoline by potentiometry in aqueous and mixed organic-water solvent systems

International Nuclear Information System (INIS)

Hafiz, A; Indhar, B.; Khanzada, A.W.K.

2000-01-01

The ionization constant pKa and Gibbs's free energy DG of 6-methylquinoline are determined in aqueous solution at different temperatures and in three mixed organic-water solvent systems at 25 deg. C. It is observed that dissociation constant of 6-methylquinoline in aqueous system decreases with the increase of temperature. The curve is a parabolic. It is noted that pKa values of this compound are higher than those of quinoline and 8-methylquinoline. In case of mixed organic-water solvent systems, the influence of these solvents on the ionization equilibria of NH/sub 2/ group has been observed. The pK M/A and pK T/A values versus percent composition decrease gradually with increase in percent of organic solvents The curve of the pK/sub a/ versus percent composition is a distorted parabola. The data have been obtained potentiometrically by titrating 6-methylquinoline solutions with HCl. The values of dissociation constant were obtained from these data by a computer program written in GW-BASIC. From pKa values Gibbs's free energies DG for the respective pKa values have also been calculated. (author)

FORMATION CONSTANTS AND THERMODYNAMIC ...

African Journals Online (AJOL)

KEY WORDS: Metal complexes, Schiff base ligand, Formation constant, DFT calculation ... best values for the formation constants of the proposed equilibrium model by .... to its positive charge distribution and the ligand deformation geometry.

Determination of dissociation constants for coordination compounds of Cr(III) and Co(III) using potentiometric and spectrophotometric methods

International Nuclear Information System (INIS)

Chylewska, A.; Jacewicz, D.; Zarzeczanska, D.; Chmurzynski, L.

2008-01-01

The acid-base properties of analogous complex ions of chromium(III) and cobalt(III) in aqueous solution have been studied. The equilibrium constants for all metal complexes were determined by using potentiometric and spectrophotometric titration methods. First, dissociation constants for the studied complexes of Cr(III) and Co(III) were determined by means of the potentiometric titration method and using the STOICHIO computer programme. Then, pH-spectrophotometric titrations were performed and the OriginPro 7.5 computer programme was used to calculate the same constants. The measurements using both methods were carried out under the same conditions of temperature, T = 298.15 K, and over the same pH range 2.00-10.00, respectively. It turned out that the two methods used enabled us to obtain acidity constants in very good agreement

Determination of dissociation constants for coordination compounds of Cr(III) and Co(III) using potentiometric and spectrophotometric methods

Energy Technology Data Exchange (ETDEWEB)

Chylewska, A.; Jacewicz, D.; Zarzeczanska, D. [Department of Chemistry, University of Gdansk, Sobieskiego 18/19, 80-952 Gdansk (Poland); Chmurzynski, L. [Department of Chemistry, University of Gdansk, Sobieskiego 18/19, 80-952 Gdansk (Poland)], E-mail: lech@chem.univ.gda.pl

2008-08-15

The acid-base properties of analogous complex ions of chromium(III) and cobalt(III) in aqueous solution have been studied. The equilibrium constants for all metal complexes were determined by using potentiometric and spectrophotometric titration methods. First, dissociation constants for the studied complexes of Cr(III) and Co(III) were determined by means of the potentiometric titration method and using the STOICHIO computer programme. Then, pH-spectrophotometric titrations were performed and the OriginPro 7.5 computer programme was used to calculate the same constants. The measurements using both methods were carried out under the same conditions of temperature, T = 298.15 K, and over the same pH range 2.00-10.00, respectively. It turned out that the two methods used enabled us to obtain acidity constants in very good agreement.

Experimental investigation of methane release from hydrate formation in sandstone through both hydrate dissociation and CO{sub 2} sequestration

Energy Technology Data Exchange (ETDEWEB)

Husebo, J.; Graue, A.; Kvamme, B. [Bergen Univ., Bergen (Norway). Dept. of Physics and Technology; Stevens, J.; Howard, J.J. [ConocoPhillips, Ponca City, OK (United States); Baldwin, B.A. [Green Country Petrophysics LLC, Dewey, OK (United States)

2008-07-01

Large amounts of natural gas trapped in hydrate reservoirs are found in Arctic regions and in deep offshore locations around the world. Natural gas production from hydrate deposits offer significant potential for future energy needs. However, research is needed in order to propose potential production schemes for natural gas hydrates. Natural gas molecules can be freed from hydrate structured cages by depressurization, by heating and by exposing the hydrate to a substance that will form a thermodynamically more stable hydrate structure. This paper provided a comparison of two approaches for releasing methane from methane hydrate in porous sandstone. The study scope covered the dissociation rate of methane hydrate in porous media through depressurization, and also referred to previous work done on producing methane from hydrates in sandstone while sequestering carbon dioxide (CO{sub 2}). The study was conducted in a laboratory setting. The paper discussed the experimental design which included the placing of a pressure- and temperature-controlled sample holder inside the bore of a magnetic resonance imager. The experimental procedures were then outlined, with reference to hydrate formation; carbon dioxide sequestration; hydrate dissociation experiments with constant volume; and hydrate dissociation experiments at constant pressure. The constant volume experiments demonstrated that in order to dissociate a large amount of hydrate, the initial depressurization had to be significantly lower than the hydrate stability pressure. 9 refs., 9 figs.

Real-time and label-free analysis of binding thermodynamics of carbohydrate-protein interactions on unfixed cancer cell surfaces using a QCM biosensor

Science.gov (United States)

Li, Xueming; Song, Siyu; Shuai, Qi; Pei, Yihan; Aastrup, Teodor; Pei, Yuxin; Pei, Zhichao

2015-01-01

A novel approach to the study of binding thermodynamics and kinetics of carbohydrate-protein interactions on unfixed cancer cell surfaces using a quartz crystal microbalance (QCM) biosensor was developed, in which binding events take place at the cell surface, more closely mimicking a biologically relevant environment. In this study, colon adenocarcinoma cells (KM-12) and ovary adenocarcinoma cells (SKOV-3) grew on the optimized polystyrene-coated biosensor chip without fixation. The association and dissociation between the cell surface carbohydrates and a range of lectins, including WGA, Con A, UEA-I, GS-II, PNA and SBA, were monitored in real time and without label for evaluation of cell surface glycosylation. Furthermore, the thermodynamic and kinetic parameters of the interaction between lectins and cell surface glycan were studied, providing detailed information about the interactions, such as the association rate constant, dissociation rate constant, affinity constant, as well as the changes of entropy, enthalpy and Gibbs free energy. This application provides an insight into the cell surface glycosylation and the complex molecular recognition on the intact cell surface, which may have impacts on disease diagnosis and drug discovery. PMID:26369583

Simultaneous determination of equivalence volumes and acid dissociation constants from potentiometric titration data.

Science.gov (United States)

Papanastasiou, G; Ziogas, I

1995-06-01

New iterative methods for analysis of potentiometric titration data of (a) mixtures of weak monoprotic acids with their conjugate bases, (b) solutions of polyprotic (di- and triprotic) acids, and (c) mixtures of two diprotic acids are presented. These methods, using data exclusively resulting from the acidic region of the titration curve permits the accurate determination of the analytical concentration of one or more acids even if the titration is stopped well before the end point of the titration. For the titration of a solution containing a conjugate acid/base pair, the proposed procedure enables the extraction of the initial composition of the mixture, as well as the dissociation constant of the concerned acid. Thus, it is possible by this type of analysis to distinguish whether a weak acid has been contaminated by a strong base and define the extent of the contamination. On the other hand, for the titration of polyprotic acids, the proposed approach enables the extraction of the accurate values of the equivalence volume and the dissociation constants K(i) even when the ionization stages overlap. Finally, for the titration of a mixture of two diprotic acids the proposed procedure enables the determination of the composition of the mixture even if the sum of the concentrations of the acids is not known. This method can be used in the analysis of solutions containing two diastereoisomeric forms of a weak diprotic acid. The test of the proposed procedures by means of ideal and Monte Carlo simulated data revealed that these methods are fairly applicable even when the titration data are considerably obscured by 'noise' or contain an important systematic error. The proposed procedures were also successfully applied to experimental titration data.

Zero-Point Energy Constraint for Unimolecular Dissociation Reactions. Giving Trajectories Multiple Chances To Dissociate Correctly.

Science.gov (United States)

Paul, Amit K; Hase, William L

2016-01-28

A zero-point energy (ZPE) constraint model is proposed for classical trajectory simulations of unimolecular decomposition and applied to CH4* → H + CH3 decomposition. With this model trajectories are not allowed to dissociate unless they have ZPE in the CH3 product. If not, they are returned to the CH4* region of phase space and, if necessary, given additional opportunities to dissociate with ZPE. The lifetime for dissociation of an individual trajectory is the time it takes to dissociate with ZPE in CH3, including multiple possible returns to CH4*. With this ZPE constraint the dissociation of CH4* is exponential in time as expected for intrinsic RRKM dynamics and the resulting rate constant is in good agreement with the harmonic quantum value of RRKM theory. In contrast, a model that discards trajectories without ZPE in the reaction products gives a CH4* → H + CH3 rate constant that agrees with the classical and not quantum RRKM value. The rate constant for the purely classical simulation indicates that anharmonicity may be important and the rate constant from the ZPE constrained classical trajectory simulation may not represent the complete anharmonicity of the RRKM quantum dynamics. The ZPE constraint model proposed here is compared with previous models for restricting ZPE flow in intramolecular dynamics, and connecting product and reactant/product quantum energy levels in chemical dynamics simulations.

Statistical thermodynamics

International Nuclear Information System (INIS)

Hwang, Jeong Ui; Jang, Jong Jae; Jee, Jong Gi

1987-01-01

The contents of this book are thermodynamics on the law of thermodynamics, classical thermodynamics and molecule thermodynamics, basics of molecule thermodynamics, molecule and assembly partition function, molecule partition function, classical molecule partition function, thermodynamics function for ideal assembly in fixed system, thermodynamics function for ideal assembly in running system, Maxwell-Boltzmann's law of distribution, chemical equilibrium like calculation of equilibrium constant and theory of absolute reaction rate.

Constants and thermodynamics of the acid-base equilibria of triglycine in water-ethanol solutions containing sodium perchlorate at 298 K

Science.gov (United States)

Pham Tkhi, L.; Usacheva, T. R.; Tukumova, N. V.; Koryshev, N. E.; Khrenova, T. M.; Sharnin, V. A.

2016-02-01

The acid-base equilibrium constants for glycyl-glycyl-glycine (triglycine) in water-ethanol solvents containing 0.0, 0.1, 0.3, and 0.5 mole fractions of ethanol are determined by potentiometric titration at 298.15 K and an ionic strength of 0.1, maintained with sodium perchlorate. It is established that an increase in the ethanol content in the solvent reduces the dissociation constant of the carboxyl group of triglycine (increases p K 1) and increases the dissociation constant of the amino group of triglycine (decreases p K 2). It is noted that the weakening of the acidic properties of a triglycinium ion upon an increase of the ethanol content in the solvent is due to the attenuation of the solvation shell of the zwitterionic form of triglycine, and to the increased solvation of triglycinium ions. It is concluded that the acid strength of triglycine increases along with a rise in the EtOH content in the solvent, due to the desolvation of the tripeptide zwitterion and the enhanced solvation of protons.

Experimental study and thermodynamic modelling of methane clathrate hydrate dissociation conditions in silica gel porous media in the presence of methanol aqueous solution

International Nuclear Information System (INIS)

Hashemi, Hamed; Javanmardi, Jafar; Zarifi, Mojdeh; Eslamimanesh, Ali; Mohammadi, Amir H.

2012-01-01

Highlights: ► Phase equilibria of hydrates of methane in confined silica gel pores are reported. ► Dissociation data in the presences of methanol aqueous solution are also measured. ► A thermodynamic model is developed for prediction of the obtained data. ► Acceptable agreement is found between the obtained data and the predicted results. - Abstract: In this work, the phase equilibria of clathrate hydrates of methane in the presence of pure water and 0.035 mass fraction of methanol aqueous solution in confined silica gel pores with (10 and 15) nm mean diameters are measured and reported. A thermodynamic model is also developed for prediction of the obtained experimental hydrate dissociation data. The Valderrama–Patel–Teja (VPT-EoS) equation of state (EoS) accompanied with the non-density dependent (NDD) mixing rules coupled with a previously developed activity model are applied to evaluate the fugacity of the species present and the activity coefficient of water in methanol aqueous solution. Acceptable agreement between the reported data and the predicted results using the proposed model and an existing method reported in the literature demonstrates the reliability of the presented model.

Increased bone calcium dissociation in lead-exposed rats

Directory of Open Access Journals (Sweden)

Eko Suhartono

2012-12-01

Full Text Available Background Lead is still a major environmental and occupational health hazard, since it is extensively used in the production of paints, gasoline and cosmetics. This causes the metal to be ubiquitous in the environment, being found in the air, soil, and water, from which it can enter the human body by inhalation or ingestion. Absorbed lead is capable of altering the calcium levels in bone. The aim of this study was to demonstrate the effect of lead on bone calcium levels by measuring the reaction constant, Gibbs free energy, and enthalpy. Methods This study was of pure experimental design using 100 male albino rats (Rattus norvegicus. The experimental animals were assigned by simple randomization to two groups, one group receiving lead acetate orally at a dosage of 100 mg/kgBW, while the other group did not receive lead acetate. The intervention was given for 4 weeks and the rats were observed weekly for measurement of bone calcium levels by the permanganometric method. Results This study found that k1 (hydroxyapatite dissociation rate constant was 0.90 x 10-3 dt-1, and that k2 (hydroxyapatite association rate constant was 6.16 x 10-3 dt-1 for the control group, whereas for the intervention group k1 = 26.20 x 10-3 dt-1 and k2 = 16.75 x 10-3 dt-1. Thermodynamically, the overall reaction was endergonic and endothermic (DG > 0 and DH > 0. ConclusionS Lead exposure results in increased dissociation rate of bone in comparison with its association rate. Overall, the reaction was endergonic and endothermic (DG > 0 and DH > 0.

Increased bone calcium dissociation in lead-exposed rats

Directory of Open Access Journals (Sweden)

Eko Suhartono

2015-12-01

Full Text Available BACKGROUND Lead is still a major environmental and occupational health hazard, since it is extensively used in the production of paints, gasoline and cosmetics. This causes the metal to be ubiquitous in the environment, being found in the air, soil, and water, from which it can enter the human body by inhalation or ingestion. Absorbed lead is capable of altering the calcium levels in bone. The aim of this study was to demonstrate the effect of lead on bone calcium levels by measuring the reaction constant, Gibbs free energy, and enthalpy. METHODS This study was of pure experimental design using 100 male albino rats (Rattus norvegicus. The experimental animals were assigned by simple randomization to two groups, one group receiving lead acetate orally at a dosage of 100 mg/ kgBW, while the other group did not receive lead acetate. The intervention was given for 4 weeks and the rats were observed weekly for measurement of bone calcium levels by the permanganometric method. RESULTS This study found that k1 (hydroxyapatite dissociation rate constant was 0.90 x 10-3 dt-1, and that k2 (hydroxyapatite association rate constant was 6.16 x 10-3 dt-1 for the control group, whereas for the intervention group k1 = 26.20 x 10-3 dt-1 and k2 = 16.75 x 10-3 dt-1. Thermodynamically, the overall reaction was endergonic and endothermic (ΔG > 0 and ΔH > 0. CONCLUSIONS Lead exposure results in increased dissociation rate of bone in comparison with its association rate. Overall, the reaction was endergonic and endothermic (ΔG > 0 and ΔH > 0.

Steroids as immunochemical probes; thermodynamic and kinetic data with special regards to the 'bridge problem' in estrogen radioimmunoassay

International Nuclear Information System (INIS)

Kuss, E.; Dirr, W.; Goebel, R.; Gloning, K.; Hoetzinger, H.; Link, M.; Thoma, H.

1977-01-01

The binding sites of antibodies raised against estrogen-6-one-oxime-0-carboxymethyl-derivatives attached to epsilon-amino groups of lysine residues in albumin were mapped thermodynamically and kinetically by reactions with labelled and unlabelled haptens. By equilibrium dialysis Gibbs energies were found to amount to about -14 kcal/mol, to be rather uniformly distributed, and to be predominantly enthalpy contributed. From unlabeled haptens their potencies to inhibit binding of labeled ligands were determined, which values are related to their binding energies. The structures of the series of systematically varied unlabelled haptens approached increasingly the structure of the immunodeterminant. Ranking the inhibition potencies of this series revealed that estrogen-6-one exhibited the highest potency, even higher than the inhibition potency of the estrogen-6-one-oxime-0-carboxymethyl-lysine derivative, which is obviously most closely related to the immunodeterminant group. To prove whether the inhibition potencies were actually restricted by the size of the antibody-binding site, both components of the equilibrium constants were determined, the association rate constants and the dissociation rate constants. Structure dependent variation of both indicated that explanation of the binding processes in terms of only the equilibrium constants was insufficient. Association reaction rates decreased with increasing length of the hapten molecules. Inversely dissociation rates decreased, but the slowest dissociation rate was observed on complexes of antibodies with estrogen-6-one-oxime-0-methylether. Further lengthening of the hapten had no effect on the dissociation rate. It was concluded that this ligand reflects the size of antibody binding site. (orig.) [de

Solubility behavior of narcotic analgesics in aqueous media: solubilities and dissociation constants of morphine, fentanyl, and sufentanil.

Science.gov (United States)

Roy, S D; Flynn, G L

1989-02-01

The pH dependence of the aqueous solubility of morphine, fentanyl, and sufentanil was investigated at 35 degrees C. Dissociation constants and corresponding pKa' values of the drugs were obtained from measured free-base solubilities (determined at high pH's) and the concentrations of saturated solutions at intermediate pH's. Morphine, fentanyl, and sufentanil exhibited pKa' values of 8.08, 8.99, and 8.51, respectively. Over the pH range of 5 to 12.5 the apparent solubilities are determined by the intrinsic solubility of the free base plus the concentration of ionized drug necessary to satisfy the dissociation equilibrium at a given pH. Consequently, the drug concentrations of saturated aqueous solutions fall off precipitously as the pH is raised and ionization is suppressed. Further, at low pH's the aqueous solubility of morphine increased in a linear fashion with increases in the molar strength of citric acid which was added to acidify the medium, suggesting the formation of a soluble morphine-citrate complex.

Comparison of the binding constant (Ksub(D)) of /sup 125/I-labelled 3-(4-iodophenoxy)-1-isopropylaminopropan-2-ol obtained on. beta. -adrenoceptors in guinea-pig myocardial membranes, with its dissociation constants (Ksub(B)) obtained on guinea-pig isolated atria and trachea

Energy Technology Data Exchange (ETDEWEB)

O' Donnell, S R [Queensland Univ., Brisbane (Australia). Dept. Of Physiology; Woodcock, E A

1978-02-01

The dissociation constant of binding (Ksub(D) of /sup 125/I-labelled 3-(4-iodophenoxy)-isopropylaminopropan-2-ol (IIP) to guinea pig myocardial membrane preparations was 2.2 x 10/sup -8/M. In pharmacological experiments with non-labelled material and 60 min contact time, IIP produced a parallel shift in the orciprenaline concentration-response line on guinea-pig isolated tracheal and atrial preparations. The dissociation constant (Ksub(B) of IIP was 2.9 x 10/sup -8/M on atria (pA/sub 2/ 7.54) and 3.3 x 10/sup -8/M on trachea (PA/sub 2/ 7.48). These values indicate that IIP is not a selective B-adrenoceptor blocking drug. In addition, agreement was found between the affinity constant of this antagonist for B-adrenoceptors as determined by a direct binding study and an indirect pharmacological study.

Thermodynamic cycle calculations for a pumped gaseous core fission reactor

International Nuclear Information System (INIS)

Kuijper, J.C.; Van Dam, H.

1991-01-01

Finite and 'infinitesimal' thermodynamic cycle calculations have been performed for a 'solid piston' model of a pumped Gaseous Core Fission Reactor with dissociating reactor gas, consisting of Uranium, Carbon and Fluorine ('UCF'). In the finite cycle calculations the influence has been investigated of several parameters on the thermodynamics of the system, especially on the attainable direct (nuclear to electrical) energy conversion efficiency. In order to facilitate the investigation of the influence of dissociation, a model gas, 'Modelium', was developed, which approximates, in a simplified, analytical way, the dissociation behaviour of the 'real' reactor gas. Comparison of the finite cycle calculation results with those of a so-called infinitesimal Otto cycle calculation leads to the conclusion that the conversion efficiency of a finite cycle can be predicted, without actually performing the finite cycle calculation, with reasonable accuracy, from the so-called 'infinitesimal efficiency factor', which is determined only by the thermodynamic properties of the reactor gas used. (author)

A new sensitive method of dissociation constants determination based on the isohydric solutions principle.

Science.gov (United States)

Michałowski, Tadeusz; Pilarski, Bogusław; Asuero, Agustin G; Dobkowska, Agnieszka

2010-10-15

The paper provides a new formulation and analytical proposals based on the isohydric solutions concept. It is particularly stated that a mixture formed, according to titrimetric mode, from a weak acid (HX, C(0)mol/L) and a strong acid (HB, Cmol/L) solutions, assumes constant pH, independently on the volumes of the solutions mixed, provided that the relation C(0)=C+C(2)·10(pK(1)) is valid, where pK(1)=-log K(1), K(1) the dissociation constant for HX. The generalized formulation, referred to the isohydric solutions thus obtained, was extended also to more complex acid-base systems. Particularly in the (HX, HB) system, the titration occurs at constant ionic strength (I) value, not resulting from presence of a basal electrolyte. This very advantageous conjunction of the properties provides, among others, a new, very sensitive method for verification of pK(1) value. The new method is particularly useful for weak acids HX characterized by low pK(1) values. The method was tested experimentally on four acid-base systems (HX, HB), in aqueous and mixed-solvent media and compared with the literature data. Some useful (linear and hyperbolic) correlations were stated and applied for validation of pK(1) values. Finally, some practical applications of analytical interest of the isohydricity (pH constancy) principle as one formulated in this paper were enumerated, proving the usefulness of such a property which has its remote roots in the Arrhenius concept. Copyright © 2010 Elsevier B.V. All rights reserved.

Determination of acid-base dissociation constants of amino- and guanidinopurine nucleotide analogues and related compounds by capillary zone electroforesis

Czech Academy of Sciences Publication Activity Database

Šolínová, Veronika; Kašička, Václav; Koval, Dušan; Česnek, Michal; Holý, Antonín

2006-01-01

Roč. 27, č. 5/6 (2006), s. 1006-1019 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA203/03/0716; GA ČR(CZ) GA203/04/0098; GA AV ČR(CZ) 1QS400550501; GA MŠk(CZ) 1M0508; GA ČR(CZ) GA203/05/2539 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * capillary electrophoresis * dissociation constant Subject RIV: CC - Organic Chemistry Impact factor: 4.101, year: 2006

Measurement of the Dissociation-Equilibrium Constants for Low Affinity Antibiotic Binding Interaction with Bacterial Ribosomes by the T2 (CPMG) and Line-Broadening Methods

Science.gov (United States)

Verdier, L.; Gharbi-Benarous, J.; Bertho, G.; Mauvais, P.; Girault, J.-P.

1999-10-01

In this study the dissociation constants of the low antibiotic-ribosomes interaction were determined by the T2 (CPMG), the Carr-Purcell-Meiboom-Gill spin-echo decay rate and the line-broadening methods. Three MLSB antibiotics were studied, a macrolide roxithromycin, a ketolide HMR 3647 and a lincosamide clindamycin for their weak interaction with three bacterial ribosomes, E. coli, Staphylococcus aureus sensitive and resistant to erythromycin. Nous avons mesuré la constante de dissociation, Kd correspondant à l'interaction faible antibiotique-ribosome bactérien pour des antibiotiques de différentes classes, un macrolide (roxithromycine), un kétolide (HMR 3647) et une lincosamide (clindamycine) avec des ribosomes de différentes souches bactériennes (E. coli, Staphylococcus aureus sensible ou résistant à l'erythromycin) par deux méthodes : l'une basée sur la variation des largeurs de raies et l'autre sur les temps de relaxation transversaux T2 en utilisant une séquence CPMG.

Capillary electrophoresis - inductively coupled plasma mass spectrometry (CE-ICPMS) coupling to assess pentavalent actinides thermodynamic constants

International Nuclear Information System (INIS)

Topin, S.; Baglan, N.; Aupiais, J.

2009-01-01

Full text: Aiming to investigate plutonium speciation at trace levels, we coupled capillary electrophoresis, a high resolution separation technique with inductively coupled plasma mass spectrometry, a detector with high sensitivity for plutonium. The research work performed to optimize the coupling is discussed based on the following criteria: the migration time, the resolution and the detection limit. The capabilities of the analytical tool are demonstrated by determining thermodynamic constants for pentavalent plutonium, and neptunium as a reference, in the presence of inorganic ligands. (author)

Thermodynamic modeling of trivalent Am, Cm and Eu-citrate complexation in concentrated NaClO{sub 4} media

Energy Technology Data Exchange (ETDEWEB)

Thakur, P.; Xiong, Y. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Borkowski, M. [Los Alamos National Laboratory, Carlsbad, NM (United States). Carlsbad Operations; Choppin, G.R. [Sandia National Laboratories, Carlsbad, NM (United States). Carlsbad Program Group

2012-07-01

The dissociation constants of citric acid (Cit), and the stability constants of Am{sup 3+}, Cm{sup 3+} and Eu{sup 3+} with Cit were determined as a function of ionic strength (NaClO{sub 4}) using potentiometric titration and an extraction technique, respectively. The results have shown the presence of both 1:1 and 1:2 complexes under the experimental conditions. A thermodynamic model was constructed to predict the apparent stability constants at different ionic strengths by applying the Pitzer ionic interaction parameters {beta}{sup (0)}, {beta}{sup (1)}, and C{sup {phi}} which were obtained to fit the experimental data. Thermodynamic stability constants of M(Cit) and M(Cit){sub 2}{sup 3-} (where M = Am{sup 3+}, Cm{sup 3+} or Eu{sup 3+}) were calculated to be log {beta}{sub 101}{sup 0} = 9.91 {+-} 0.10, log {beta}{sub 102}{sup 0} = 14.47 {+-} 0.14 for Am{sup 3+}, log {beta}{sub 101}{sup 0} = 9.53 {+-} 0.16, log {beta}{sub 102}{sup 0} = 14.46 {+-} 0.16 for Cm{sup 3+} and log {beta}{sub 101}{sup 0} = 9.82 {+-} 0.14, log {beta}{sub 102}{sup 0} = 13.31 {+-} 0.12 for Eu{sup 3+} as obtained by extrapolation to zero ionic strength. (orig.)

STABILITY CONSTANT OF THE TRISGLYCINATO METAL ...

African Journals Online (AJOL)

DR. AMINU

overall stability constants of the complexes were found to be similar. Keywords: Glycinato, titration ... +. −. = 1 where Ka = dissociation constant of the amino acid. [ ]+. H = concentration of the .... Synthesis and techniques in inorganic chemistry.

Determination of the Acid Dissociation Constant of a Phenolic Acid by High Performance Liquid Chromatography: An Experiment for the Upper Level Analytical Chemistry Laboratory

Science.gov (United States)

Raboh, Ghada

2018-01-01

A high performance liquid chromatography (HPLC) experiment for the upper level analytical chemistry laboratory is described. The students consider the effect of mobile-phase composition and pH on the retention times of ionizable compounds in order to determine the acid dissociation constant, K[subscript a], of a phenolic acid. Results are analyzed…

Water dimers in the atmosphere III: equilibrium constant from a flexible potential.

Science.gov (United States)

Scribano, Yohann; Goldman, Nir; Saykally, R J; Leforestier, Claude

2006-04-27

We present new results for the water dimer equilibrium constant K(p)(T) in the range 190-390 K, using a flexible potential energy surface fitted to spectroscopical data. The increased numerical complexity due to explicit consideration of the monomer vibrations is handled via an adiabatic (6 + 6)d decoupling between intra- and intermolecular modes. The convergence of the canonical partition function of the dimer is ensured by computing all energy levels up to dissociation for total angular momentum values J = 0-5 and using an extrapolation scheme to higher values. The newly calculated values for K(p)(T) are in very good agreement with available experimental data at room temperature. At higher temperatures, an analysis of the convergence of the partition function reveals that quasi-bound states are likely to contribute to the equilibrium constant. Additional thermodynamical quantities (deltaG, deltaH, deltaS, and C(p)) have also been determined and fit to quadratic expressions a + bT + cT2.

Determination of dissociation constants or propionic acid and lactic acid (2-hydroxypropionic acid) by potentiometry and conductometry

International Nuclear Information System (INIS)

Saeeduddin; Khanzada, A.W.K.

2004-01-01

Dissociation constants of propionic acid and 2-hydroxypropionic acid (lactic acid) have been studied at different temperatures between 25 to 50 deg. C interval. Propionic acid is analyzed by conductometry while 2-hydroxypropionic acid is analyzed by potentiometry. Both investigated compounds are symmetrical carboxylic acids having same length of carbon chain but are markedly different in ionic behavior. We were interested to see how the hydroxyl group (-OH) induction in propionic acid affects on pKa values of 2-hydroxypropionic acid. We observed that as temperature increases pKa values increase. The increase is observed for both the investigated compounds. PKa values of 2-hydroxypropionic acid are lower as compared to propionic acid because of electron withdrawing (-OH). (author)

Communication: The highest frequency hydrogen bond vibration and an experimental value for the dissociation energy of formic acid dimer

DEFF Research Database (Denmark)

Kollipost, F.; Larsen, René Wugt; Domanskaya, A.V.

2012-01-01

The highest frequency hydrogen bond fundamental of formic acid dimer, ν24 (Bu), is experimentally located at 264 cm−1. FTIR spectra of this in-plane bending mode of (HCOOH)2 and band centers of its symmetric D isotopologues (isotopomers) recorded in a supersonic slit jet expansion are presented...... thermodynamics treatment of the dimerization process up to room temperature. We obtain D0 = 59.5(5) kJ/mol as the best experimental estimate for the dimer dissociation energy at 0 K. Further improvements have to wait for a more consistent determination of the room temperature equilibrium constant....

Concise chemical thermodynamics

CERN Document Server

Peters, APH

2010-01-01

EnergyThe Realm of ThermodynamicsEnergy BookkeepingNature's Driving ForcesSetting the Scene: Basic IdeasSystem and SurroundingsFunctions of StateMechanical Work and Expanding GasesThe Absolute Temperature Scale Forms of Energy and Their Interconversion Forms of Renewable Energy Solar Energy Wind Energy Hydroelectric Power Geothermal Energy Biomass Energy References ProblemsThe First Law of Thermodynamics Statement of the First Law Reversible Expansion of an Ideal GasConstant-Volume ProcessesConstant-Pressure ProcessesA New Function: EnthalpyRelationship between ?H and ?UUses and Conventions of

Measurement of acid dissociation constants of weak acids by cation exchange and conductometry

Energy Technology Data Exchange (ETDEWEB)

Dasgupta, P.K.; Nara, Osamu (Texas Tech Univ., Lubbock (USA))

1990-06-01

A simple strategy is presented for the determination of acid dissociation constants based on the measurement of conductance of a known concentration of the acid and/or the conductance of a solution of its fully or partially neutralized alkali-metal salts. For an n-protic acid, 2n conductance measurements are minimally necessary. In the simplest case of a typical monoprotic acid, the conductance of its alkali salt solution is measured before and after passage through an H{sup +}-form exchanger. From these data both the pK{sub a} of the acid and the equivalent conductance of the anion can be computed. The underlying equations are rigorously solved for monoprotic acids and some diprotic acid systems. For other diprotic and multiprotic acid systems, initial estimates are obtained by making approximations; the complete data set is then subjected to multiparametric fitting. The method does not require pH measurements; conductance can generally be measured accurately at low enough ionic strengths to obviate the need for major activity correction. Several experimental measurements are presented and excellent agreement with literature pK{sub a} values is observed. The reliability of the equivalent conductance values computed in this fashion is limited, however.

Determination of the Tetramer-Dimer Equilibrium Constant of Rabbit ...

African Journals Online (AJOL)

Hemoglobin is a tetrameric protein which is able to dissociate into dimers. The dimers can in turn dissociate into tetramers. It has been found that dimers are more reactive than tetramers. The difference in the reactivity of these two species has been used to determine the tetramerdimer dissociation constant of various ...

Thermodynamic Constraints in Using AuM (M = Fe, Co, Ni, and Mo) Alloys as N₂ Dissociation Catalysts: Functionalizing a Plasmon-Active Metal.

Science.gov (United States)

Martirez, John Mark P; Carter, Emily A

2016-02-23

The Haber-Bosch process for NH3 synthesis is arguably one of the greatest inventions of the 20th century, with a massive footprint in agriculture and, historically, warfare. Current catalysts for this reaction use Fe for N2 activation, conducted at high temperatures and pressures to improve conversion rate and efficiency. A recent finding shows that plasmonic metal nanoparticles can either generate highly reactive electrons and holes or induce resonant surface excitations through plasmonic decay, which catalyze dissociation and redox reactions under mild conditions. It is therefore appealing to consider AuM (M = Fe, Co, Ni, and Mo) alloys to combine the strongly plasmonic nature of Au and the catalytic nature of M metals toward N2 dissociation, which together might facilitate ammonia production. To this end, through density functional theory, we (i) explore the feasibility of forming these surface alloys, (ii) find a pathway that may stabilize/deactivate surface M substituents during fabrication, and (iii) define a complementary route to reactivate them under operational conditions. Finally, we evaluate their reactivity toward N2, as well as their ability to support a pathway for N2 dissociation with a low thermodynamic barrier. We find that AuFe possesses similar appealing qualities, including relative stability with respect to phase separation, reversibility of Fe oxidation and reduction, and reactivity toward N2. While AuMo achieves the best affinity toward N2, its strong propensity toward oxidation could greatly limit its use.

Thermodynamics of nanoadsorption from solution: Theoretical and experimental research

International Nuclear Information System (INIS)

Wen, Yan-Zhen; Xue, Yong-Qiang; Cui, Zi-Xiang; Wang, Yan

2015-01-01

Highlights: • The thermodynamic theory of nanoadsorption was proposed. • The thermodynamic relations of nanoadsorption were derived. • The results of the experiments are accord with the theory. - Abstract: In this study, the effect of nanoparticle size on adsorption thermodynamics was investigated. The results of theoretical and experimental studies show that particle size significantly affects the equilibrium constant and thermodynamic properties of nanoadsorption. Relationships between the equilibrium constant, thermodynamic properties and particle size were derived using the thermodynamic theory of nanoadsorption. The equilibrium constant and thermodynamic properties were obtained by investigating the adsorption of Cu 2+ onto different sizes of nano-ZnO and the adsorption of Ag + onto different sizes of nano-TiO 2 . Good agreement was achieved between results obtained by experiments and predicted by theoretical analyses. The equilibrium constant and the molar Gibbs free energy of nanoadsorption were found to increase with smaller nanoparticle size. However, the effects of particle size on the molar enthalpy and the molar entropy are uncertain. In addition, the molar Gibbs free energy, the molar enthalpy, the molar entropy and the logarithm of the equilibrium constant are linearly related to the reciprocal of the diameter of the nanoparticle. The thermodynamic properties revealed in this study may provide important guidelines for research and application in the field of nanoadsorption

Dehydrogenation Kinetics and Modeling Studies of MgH2 Enhanced by Transition Metal Oxide Catalysts Using Constant Pressure Thermodynamic Driving Forces

Directory of Open Access Journals (Sweden)

Saidi Temitope Sabitu

2012-06-01

Full Text Available The influence of transition metal oxide catalysts (ZrO2, CeO2, Fe3O4 and Nb2O5 on the hydrogen desorption kinetics of MgH2 was investigated using constant pressure thermodynamic driving forces in which the ratio of the equilibrium plateau pressure (pm to the opposing plateau (pop was the same in all the reactions studied. The results showed Nb2O5 to be vastly superior to other catalysts for improving the thermodynamics and kinetics of MgH2. The modeling studies showed reaction at the phase boundary to be likely process controlling the reaction rates of all the systems studied.

Detonation Jet Engine. Part 1--Thermodynamic Cycle

Science.gov (United States)

Bulat, Pavel V.; Volkov, Konstantin N.

2016-01-01

We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

A constitutive rheological model for agglomerating blood derived from nonequilibrium thermodynamics

Science.gov (United States)

Tsimouri, Ioanna Ch.; Stephanou, Pavlos S.; Mavrantzas, Vlasis G.

2018-03-01

Red blood cells tend to aggregate in the presence of plasma proteins, forming structures known as rouleaux. Here, we derive a constitutive rheological model for human blood which accounts for the formation and dissociation of rouleaux using the generalized bracket formulation of nonequilibrium thermodynamics. Similar to the model derived by Owens and co-workers ["A non-homogeneous constitutive model for human blood. Part 1. Model derivation and steady flow," J. Fluid Mech. 617, 327-354 (2008)] through polymer network theory, each rouleau in our model is represented as a dumbbell; the corresponding structural variable is the conformation tensor of the dumbbell. The kinetics of rouleau formation and dissociation is treated as in the work of Germann et al. ["Nonequilibrium thermodynamic modeling of the structure and rheology of concentrated wormlike micellar solutions," J. Non-Newton. Fluid Mech. 196, 51-57 (2013)] by assuming a set of reversible reactions, each characterized by a forward and a reverse rate constant. The final set of evolution equations for the microstructure of each rouleau and the expression for the stress tensor turn out to be very similar to those of Owens and co-workers. However, by explicitly considering a mechanism for the formation and breakage of rouleaux, our model further provides expressions for the aggregation and disaggregation rates appearing in the final transport equations, which in the kinetic theory-based network model of Owens were absent and had to be specified separately. Despite this, the two models are found to provide similar descriptions of experimental data on the size distribution of rouleaux.

Chemical Thermodynamics of Aqueous Atmospheric Aerosols: Modeling and Microfluidic Measurements

Science.gov (United States)

Nandy, L.; Dutcher, C. S.

2017-12-01

Accurate predictions of gas-liquid-solid equilibrium phase partitioning of atmospheric aerosols by thermodynamic modeling and measurements is critical for determining particle composition and internal structure at conditions relevant to the atmosphere. Organic acids that originate from biomass burning, and direct biogenic emission make up a significant fraction of the organic mass in atmospheric aerosol particles. In addition, inorganic compounds like ammonium sulfate and sea salt also exist in atmospheric aerosols, that results in a mixture of single, double or triple charged ions, and non-dissociated and partially dissociated organic acids. Statistical mechanics based on a multilayer adsorption isotherm model can be applied to these complex aqueous environments for predictions of thermodynamic properties. In this work, thermodynamic analytic predictive models are developed for multicomponent aqueous solutions (consisting of partially dissociating organic and inorganic acids, fully dissociating symmetric and asymmetric electrolytes, and neutral organic compounds) over the entire relative humidity range, that represent a significant advancement towards a fully predictive model. The model is also developed at varied temperatures for electrolytes and organic compounds the data for which are available at different temperatures. In addition to the modeling approach, water loss of multicomponent aerosol particles is measured by microfluidic experiments to parameterize and validate the model. In the experimental microfluidic measurements, atmospheric aerosol droplet chemical mimics (organic acids and secondary organic aerosol (SOA) samples) are generated in microfluidic channels and stored and imaged in passive traps until dehydration to study the influence of relative humidity and water loss on phase behavior.

A combined thermodynamic cycle based on methanol dissociation for IC (internal combustion) engine exhaust heat recovery

International Nuclear Information System (INIS)

Fu, Jianqin; Liu, Jingping; Xu, Zhengxin; Ren, Chengqin; Deng, Banglin

2013-01-01

In this paper, a novel approach for exhaust heat recovery was proposed to improve IC (internal combustion) engine fuel efficiency and also to achieve the goal for direct usage of methanol as IC engine fuel. An open organic Rankine cycle system using methanol as working medium is coupled to IC engine exhaust pipe for exhaust heat recovery. In the bottom cycle, the working medium first undergoes dissociation and expansion processes, and is then directed back to IC engine as fuel. As the external bottom cycle and the IC engine main cycle are combined together, this scheme forms a combined thermodynamic cycle. Then, this concept was applied to a turbocharged engine, and the corresponding simulation models were built for both of the external bottom cycle and the IC engine main cycle. On this basis, the energy saving potential of this combined cycle was estimated by parametric analyses. Compared to the methanol vapor engine, IC engine in-cylinder efficiency has an increase of 1.4–2.1 percentage points under full load conditions, while the external bottom cycle can increase the fuel efficiency by 3.9–5.2 percentage points at the working pressure of 30 bar. The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points. - Highlights: • A combined thermodynamic cycle using methanol as working medium for IC engine exhaust heat recovery is proposed. • The external bottom cycle of exhaust heat recovery and IC engine working cycle are combined together. • IC engine fuel efficiency could be improved from both in-cylinder working cycle and external bottom cycle. • The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points at full load

Advanced thermodynamics engineering

CERN Document Server

Annamalai, Kalyan; Jog, Milind A

2011-01-01

Thermolab Excel-Based Software for Thermodynamic Properties and Flame Temperatures of Fuels IntroductionImportance, Significance and LimitationsReview of ThermodynamicsMathematical BackgroundOverview of Microscopic/NanothermodynamicsSummaryAppendix: Stokes and Gauss Theorems First Law of ThermodynamicsZeroth LawFirst Law for a Closed SystemQuasi Equilibrium (QE) and Nonquasi-equilibrium (NQE) ProcessesEnthalpy and First LawAdiabatic Reversible Process for Ideal Gas with Constant Specific HeatsFirst Law for an Open SystemApplications of First Law for an Open SystemIntegral and Differential Form

Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

Science.gov (United States)

Huber, S. E.; Śmiałek, M. A.; Tanzer, K.; Denifl, S.

2016-06-01

Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO-, water, and the amidogen (NH2) radical. The second and third most dominant dissociation channels are associated with formation of NCNH- and NHCONH2-, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH2-/O-, OH-, CN-, HNOH-, NCONH2-, and ONHCONH2-.

DETERMINATION OF STABILITY CONSTANTS OF MANGANESE (II ...

African Journals Online (AJOL)

DR. AMINU

Keywords: Amino acids, dissociation constant, potentiometry, stability constant. INTRODUCTION. Acids – base titration involves the gradual addition or removal of protons for example using the deprotic form of glycine. The plot has two distinct stages corresponding to the deprotonation of the two different groups on glycine.

Unification of cosmology and the second law of thermodynamics. Proposal for solving the cosmological constant and inflation problems

International Nuclear Information System (INIS)

Nielsen, Holger B.; Ninomiya, Masao

2006-01-01

We seek to unify the second law of thermodynamics with other physical laws, or, at least to find a law underlying the second law of thermodynamics. Assuming no fine tuning, using a random Hamiltonian, we argue just from the equations of motion - without the second law - that entropy cannot first increase and then decrease except with the rather strict restriction S large ≤ S small1 + S small2 . Here S large is the large' entropy in the intermediate era, while S small1 and S small2 are the entropies at certain times before and after the S large era. From this theorem asserting that there can exist no strong maximum for the entropy, we argue that an S 1 cyclic time model world could have entropy that varies by at most a factor of two and would not be phenomenologically realistic. With an open ended time axis (-∞, ∞)=R, some law underlying the second law of thermodynamics is needed if the entropy is not maximal (i.e. that heat death having y occurred at the start). We derive such a law behind the second law - or a unification of the second law with other laws - by assigning a probability weight P for finding the world/system in various places in phase space. In such a model, P is almost unified with the rest as P=exp(-2S Im ), with S Im being the imaginary part of the action. We quite naturally derive the second law for practical purposes, a Big Bang with two-sided time directions, and find that there is a need for a Hamiltonian density with a well-defined bottom. Assuming that the cosmological constant is a dynamical variable in the sense that it is counted as on 'initial condition', we even solve in our model the cosmological constant problem without using the anthropic principle. (author)

Potentiometric determination of acid dissociation constants (pKa) for human and veterinary antibiotics.

Science.gov (United States)

Qiang, Zhimin; Adams, Craig

2004-07-01

This work determined the acid dissociation constants (pKa) of 26 common human and veterinary antibiotics by potentiometric titration. Selected antibiotics consisted of sulfonamides, macrolides, tetracyclines, fluoroquinolones, and other miscellaneous antibiotics. After validation of analysis methods using phosphoric acid as a model compound, a second-derivative (delta2pH/deltaV2) method was primarily applied to determining pKa's from titration curves for most antibiotics due to its convenience and accuracy. For tetracyclines, however, a least-square non-linear regression method was developed to determine their pKa's because the second-derivative method cannot well distinguish the pKa,2 and pKa,3 of tetracyclines. Results indicate that the pKa values are approximately 2 and 5-7.5 for sulfonamides; 7.5-9 for macrolides; 3-4, 7-8 and 9-10 for tetracyclines; 3-4, 6, 7.5-9 and 10-11 for fluoroquinolones; while compound-specific for other miscellaneous antibiotics. The moieties corresponding to specific pKa's were identified based on chemical structures of antibiotics. In addition, the pKa's available in literature determined by various techniques are compiled in comparison with the values of this work. These results are expected to essentially facilitate the research on occurrence, fate and effects, analysis methods development, and control of antibiotics in various treatment operations.

Tautomers and Acid Dissociation Constants of 6-Selenoguanine from Density Functional Theoretical Calculations

International Nuclear Information System (INIS)

Kim, Yong Seong; Jang, Yun Hee; Cho, Hyun; Hwang, Sun Gu

2010-01-01

The relative stabilities of the tautomers of SeG were calculated. In the aqueous phase, amino-seleno form was the major tautomer of neutral SeG with a minor contribution from the other amino-seleno form. The presence of the selenolic form was negligible from the calculations. The microscopic and macroscopic pKa values in the aqueous phase were calculated from this scheme. The calculated pKa value was in good agreement with the experimental data. These results demonstrated that this method could predict and explain the acid-base properties of SeG and could be used to understand the behavior of the species. A number of analogues of nucleic acid bases have been the target of extensive studies because of their importance in many biological studies. The oxygen of both purine and pyrimidine bases is substituted with sulfur or selenium to produce an important class of analogues. 6-Selenoguanine (SeG) has a significant activity against L5178Y lymphoma cells. However, the detailed mechanism of the antiplastic action is not known yet. Information on the acid dissociation constants and the tautomerism of the molecules is required to provide a molecular level understanding of biological processes. Proton-transfer in the nucleic acid pairs and the presence of the tautomeric equilibrium play an important role in the mispair formation during the DNA replication

The critical release rates for the dissociating gas N204/N02/N0

International Nuclear Information System (INIS)

Porter, W.H.L.

1979-03-01

Dissociating vapour systems have certain characteristics which make them attractive as coolants, notably a large effective specific heat which is significantly greater than that for the individual components of the gas mixture, and also an enhanced boundary layer heat transfer coefficient resulting from the physical characteristics of thermal dissociation. In part these effects ensure that a dissociating gas has a greatly improved thermal capacity and heat transfer capability when compared with most inert gases. In this report the critical release rates for the dissociating vapour system N 2 0 4 -N0 2 -N0 are established, principally in the two phase region, and the thermodynamics of nitrogen tetroxide are examined. (U.K.)

Method of non-interacting thermodynamic calculation of binary phase diagrams containing p disordered phases with variable composition and q phases with constant composition at (p, q) ≤ 10

International Nuclear Information System (INIS)

Udovskij, A.L.; Karpushkin, V.N.; Nikishina, E.A.

1991-01-01

Method of non-interacting thermodynamic calculation of state diagram of binary systems contacting p disordered phases with variable composition and q phases with constant composition for (p, q) ≤ 10 case is developed. Determination of all possible solutions of phase equilibrium equations is realized in the method. Certain application examples of computer-realized method of T-x thermodynamic calculation using PC for Cr-W, Ni-W, Ni-Al, Ni-Re binary systems are given

Determine equilibrium dissociation constant of drug-membrane receptor affinity using the cell membrane chromatography relative standard method.

Science.gov (United States)

Ma, Weina; Yang, Liu; Lv, Yanni; Fu, Jia; Zhang, Yanmin; He, Langchong

2017-06-23

The equilibrium dissociation constant (K D ) of drug-membrane receptor affinity is the basic parameter that reflects the strength of interaction. The cell membrane chromatography (CMC) method is an effective technique to study the characteristics of drug-membrane receptor affinity. In this study, the K D value of CMC relative standard method for the determination of drug-membrane receptor affinity was established to analyze the relative K D values of drugs binding to the membrane receptors (Epidermal growth factor receptor and angiotensin II receptor). The K D values obtained by the CMC relative standard method had a strong correlation with those obtained by the frontal analysis method. Additionally, the K D values obtained by CMC relative standard method correlated with pharmacological activity of the drug being evaluated. The CMC relative standard method is a convenient and effective method to evaluate drug-membrane receptor affinity. Copyright © 2017 Elsevier B.V. All rights reserved.

An Experimental Determination of Thermodynamic Values

Science.gov (United States)

Antony, Erling; Muccianti, Christine; Vogel, Tracy

2012-01-01

Measurements have been added to an old demonstration of chemical equilibria allowing the determination of thermodynamic constants. The experiment allows the students an opportunity to merge qualitative observations associated with Le Chatelier's principle and thermodynamic calculations using graphical techniques. (Contains 4 figures.)

Association/dissociation in dense gases and adsorption/desorption on surfaces

International Nuclear Information System (INIS)

Flannery, M.R.

1984-01-01

A new comprehensive theory is described for the time evolution towards equilibrium of association and dissociation in a dense gas. Expressions are formulated and are illustrated for the net probabilities of association to stable vibrational levels and dissociation to the continuum from an arbitrary bound vibrational level via collision with the thermal gas bath. A general variational principle emerges: The rate which corresponds to the overall direction of the process always adjusts itself to a minimum and the time evolution towards equilibrium is hindered. Analogy is established with Kirchhoff's Laws and Tellegen's Theorem for electrical networks, and with the Principle of Least Dissipation basic to thermodynamics, heat conduction, and fluid mechanics. The theory can also be modified to provide the first basic microscopic account of Associative Desorption of atoms from and Dissociative Chemisorption of molecules to surfaces

Statistical thermodynamics of supercapacitors and blue engines

OpenAIRE

van Roij, René

2012-01-01

We study the thermodynamics of electrode-electrolyte systems, for instance supercapacitors filled with an ionic liquid or blue-energy devices filled with river- or sea water. By a suitable mapping of thermodynamic variables, we identify a strong analogy with classical heat engines. We introduce several Legendre transformations and Maxwell relations. We argue that one should distinguish between the differential capacity at constant ion number and at constant ion chemical potential, and derive ...

Thermodynamics of de Sitter universes

International Nuclear Information System (INIS)

Huang Chaoguang; Liu Liao; Wang Bobo

2002-01-01

It is shown that the first law of thermodynamics can be applied to the de Sitter universe to relate its vacuum energy, pressure, entropy of horizon, chemical potential, etc., when the cosmological constant changes due to the fluctuation of the vacuum or other reasons. The second law should be reformulated in the form that the spontaneous decay of the vacuum never makes the entropy of the de Sitter universe decrease. The third law of thermodynamics, applying to the de Sitter universe, implies that the cosmological constant cannot reach zero by finite physical processes. The relation to the holographic principle is also briefly discussed

Thermodynamics of clathrate hydrate at low and high pressures with application to the outer solar system

Science.gov (United States)

Lunine, J. I.; Stevenson, D. J.

1985-01-01

The thermodynamic stability of clathrate hydrate is calculated to predict the formation conditions corresponding to a range of solar system parameters. The calculations were performed using the statistical mechanical theory developed by van der Waals and Platteeuw (1959) and existing experimental data concerning clathrate hydrate and its components. Dissociation pressures and partition functions (Langmuir constants) are predicted at low pressure for CO clathrate (hydrate) using the properties of chemicals similar to CO. It is argued that nonsolar but well constrained noble gas abundances may be measurable by the Galileo spacecraft in the Jovian atmosphere if the observed carbon enhancement is due to bombardment of the atmosphere by clathrate-bearing planetesimals sometime after planetary formation. The noble gas abundances of the Jovian satellite Titan are predicted, assuming that most of the methane in Titan is accreted as clathrate. It is suggested that under thermodynamically appropriate conditions, complete clathration of water ice could have occurred in high-pressure nebulas around giant planets, but probably not in the outer solar nebula. The stability of clathrate in other pressure ranges is also discussed.

Equilibrium Constant as Solution to the Open Chemical Systems

OpenAIRE

Zilbergleyt, B.

2008-01-01

According to contemporary views, equilibrium constant is relevant only to true thermodynamic equilibria in isolated systems with one chemical reaction. The paper presents a novel formula that ties-up equilibrium constant and chemical system composition at any state, isolated or open as well. Extending the logarithmic logistic map of the Discrete Thermodynamics of Chemical Equilibria, this formula maps the system population at isolated equilibrium into the population at any open equilibrium at...

Intrinsic Thermodynamics and Structures of 2,4- and 3,4-Substituted Fluorinated Benzenesulfonamides Binding to Carbonic Anhydrases.

Science.gov (United States)

Zubrienė, Asta; Smirnov, Alexey; Dudutienė, Virginija; Timm, David D; Matulienė, Jurgita; Michailovienė, Vilma; Zakšauskas, Audrius; Manakova, Elena; Gražulis, Saulius; Matulis, Daumantas

2017-01-20

The goal of rational drug design is to understand structure-thermodynamics correlations in order to predict the chemical structure of a drug that would exhibit excellent affinity and selectivity for a target protein. In this study we explored the contribution of added functionalities of benzenesulfonamide inhibitors to the intrinsic binding affinity, enthalpy, and entropy for recombinant human carbonic anhydrases (CA) CA I, CA II, CA VII, CA IX, CA XII, and CA XIII. The binding enthalpies of compounds possessing similar chemical structures and affinities were found to be very different, spanning a range from -90 to +10 kJ mol -1 , and are compensated by a similar opposing entropy contribution. The intrinsic parameters of binding were determined by subtracting the linked protonation reactions. The sulfonamide group pK a values of the compounds were measured spectrophotometrically, and the protonation enthalpies were measured by isothermal titration calorimetry (ITC). Herein we describe the development of meta- or ortho-substituted fluorinated benzenesulfonamides toward the highly potent compound 10 h, which exhibits an observed dissociation constant value of 43 pm and an intrinsic dissociation constant value of 1.1 pm toward CA IX, an anticancer target that is highly overexpressed in various tumors. Fluorescence thermal shift assays, ITC, and X-ray crystallography were all applied in this work. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermodynamically consistent Bayesian analysis of closed biochemical reaction systems

Directory of Open Access Journals (Sweden)

Goutsias John

2010-11-01

Full Text Available Abstract Background Estimating the rate constants of a biochemical reaction system with known stoichiometry from noisy time series measurements of molecular concentrations is an important step for building predictive models of cellular function. Inference techniques currently available in the literature may produce rate constant values that defy necessary constraints imposed by the fundamental laws of thermodynamics. As a result, these techniques may lead to biochemical reaction systems whose concentration dynamics could not possibly occur in nature. Therefore, development of a thermodynamically consistent approach for estimating the rate constants of a biochemical reaction system is highly desirable. Results We introduce a Bayesian analysis approach for computing thermodynamically consistent estimates of the rate constants of a closed biochemical reaction system with known stoichiometry given experimental data. Our method employs an appropriately designed prior probability density function that effectively integrates fundamental biophysical and thermodynamic knowledge into the inference problem. Moreover, it takes into account experimental strategies for collecting informative observations of molecular concentrations through perturbations. The proposed method employs a maximization-expectation-maximization algorithm that provides thermodynamically feasible estimates of the rate constant values and computes appropriate measures of estimation accuracy. We demonstrate various aspects of the proposed method on synthetic data obtained by simulating a subset of a well-known model of the EGF/ERK signaling pathway, and examine its robustness under conditions that violate key assumptions. Software, coded in MATLAB®, which implements all Bayesian analysis techniques discussed in this paper, is available free of charge at http://www.cis.jhu.edu/~goutsias/CSS%20lab/software.html. Conclusions Our approach provides an attractive statistical methodology for

Knudsen cell mass spectrometric study of the Cs2IOH(g) molecule thermodynamics

International Nuclear Information System (INIS)

Roki, F-Z.; Ohnet, M-N.; Fillet, S.; Chatillon, C.; Nuta, I.

2013-01-01

Highlights: • The pronounced ionic character leads to only dissociative ionization processes. • Ions formed are same as those coming from pure dimmers. • De-convolution of the ions origin needs accurate thermodynamic values for the pure gas phase. • Mass spectrometric interpretation has to be performed gradually and as a function of suitable condensed compositions. • Thermal functions have to be fully estimated. -- Abstract: The gas phase of the CsI + CsOH system is analyzed by high temperature Knudsen cell mass spectrometry in order to confirm the existence of the Cs 2 IOH(g) complex molecule. The mass spectrometric analysis is quite complex since such molecules undergo dissociative ionization into fragment ions that mix with the same ions from dimers of the pure compounds in the same vapor phase. Varying the chemical conditions for vaporization by using different CsI + CsOH mixture contents showed that the ionization of the Cs 2 IOH(g) molecule led to five different fragment ions, Cs 2 OH + , Cs 2 I + , Cs + , CsOH + and CsI + . This complex ionization pattern was studied in relation with previous assessed values for the vaporization of CsOH and CsI pure compounds in which monomer and dimer molecules are predominant. The equilibrium constant for the reaction CsI(g) + CsOH(g) = Cs 2 IOH(g) was determined and, after modeling the structure of the Cs 2 IOH molecule, the enthalpy of formation was determined using the third law of thermodynamics, as follows: Δ f H°(Cs 2 IOH, g, 298.15 K) = −578 ± 14.7 kJ · mole −1

Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea

Energy Technology Data Exchange (ETDEWEB)

Huber, S. E.; Tanzer, K.; Denifl, S. [Institute for Ion Physics and Applied Physics and Center of Molecular Biosciences Innsbruck, Leopold Franzens University of Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Śmiałek, M. A., E-mail: smialek@pg.gda.pl [Department of Control and Power Engineering, Faculty of Ocean Engineering and Ship Technology, Gdańsk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdańsk (Poland)

2016-06-14

Dissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation channels. Moreover, thermodynamic thresholds for various fragmentation reactions are reported to support the discussion of the experimental findings. The dominant dissociation channel, which was observed over a broad range of energies, is associated with formation of NCO{sup −}, water, and the amidogen (NH{sub 2}) radical. The second and third most dominant dissociation channels are associated with formation of NCNH{sup −} and NHCONH{sub 2}{sup −}, respectively, which are both directly related to formation of the highly reactive hydroxyl radical. Other ions observed with significant abundance in the mass spectra were NH{sub 2}{sup −}/O{sup −}, OH{sup −}, CN{sup −}, HNOH{sup −}, NCONH{sub 2}{sup −}, and ONHCONH{sub 2}{sup −}.

Dissociation behavior of methane--ethane mixed gas hydrate coexisting structures I and II.

Science.gov (United States)

Kida, Masato; Jin, Yusuke; Takahashi, Nobuo; Nagao, Jiro; Narita, Hideo

2010-09-09

Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II simultaneously convert to Ih during the dissociation, but the diffraction pattern at temperatures greater than 208 K showed different dissociation behavior between structures I and II. Although the diffraction peaks from structure II decreased during measurement at constant temperatures greater than 208 K, those from structure I increased at the initial step of dissociation and then disappeared. This anomalous behavior of the methane-ethane mixed gas hydrate coexisting structures I and II was examined by using the (13)C NMR technique. The (13)C NMR spectra revealed that the anomalous behavior results from the formation of ethane-rich structure I. The structure I hydrate formation was associated with the dissociation rate of the initial methane-ethane mixed gas hydrate.

Theoretical study (ab initio and DFT methods on acidic dissociation constant of xylenol orange in aqueous solution

Directory of Open Access Journals (Sweden)

F. Kiani

2017-07-01

Full Text Available Analytical measurement of materials requires exact knowledge of their acid dissociation constant (pKa values. In recent years, quantum mechanical calculations have been extensively used to study of acidities in the aqueous solutions and the results were compared with the experimental values. In this study, a theoretical study was carried out on xylenol orange (in water solution by ab initio method. We calculated the pKa values of xylenol orange in water, using high-level ab initio (PM3, DFT (HF, B3LYP/6-31+G(d and SCRF methods. The experimental determination of these values (pKa,s is a challenge because xylenol orange has a low solubility in water. We considered several ionization reactions and equilibriums in water that constitute the indispensable theoretical basis to calculate the pKa values of xylenol orange. The results show that the calculated pKa values have a comparable agreement with the experimentally determined pKa values. Therefore, this method can be used to predict such properties for indicators, drugs and other important molecules.

Solution chemistry

Energy Technology Data Exchange (ETDEWEB)

None

1973-07-01

Research progress is reported on studies in heavy element chemistry. Topics considered are: synergistic complexes of plutonyl ion; water uptake in synergistic systems; formation constants of some uranyl BETA -diketone complexes; thermodynamic acid dissociation constants of BETA -diketones; thermodynamic formation constants of uranyl BETA -diketonates; thiocyanate complexes of some trivalent lanthanides and actinides; stability constants of actinide complexes using dinonyl naphthalenesulfonic acid extraction; TBP extraction of actinides; stability constants of complexes of Pu(III) with 5- sulfosalicycllc acid; and solvent extraction behavior of Pu( VII). (DHM)

Stochastic deformation of a thermodynamic symplectic structure

OpenAIRE

Kazinski, P. O.

2008-01-01

A stochastic deformation of a thermodynamic symplectic structure is studied. The stochastic deformation procedure is analogous to the deformation of an algebra of observables like deformation quantization, but for an imaginary deformation parameter (the Planck constant). Gauge symmetries of thermodynamics and corresponding stochastic mechanics, which describes fluctuations of a thermodynamic system, are revealed and gauge fields are introduced. A physical interpretation to the gauge transform...

Computational study of the hydrolysis of carbonyl sulphide: Thermodynamics and kinetic constants estimation using ab initio calculations

International Nuclear Information System (INIS)

Vidal-Vidal, Á.; Pérez-Rodríguez, M.; Piñeiro, M.M.

2017-01-01

Highlights: • OCS hydrolysis equilibrium constants were calculated using QM composite methods. • CBS-QB3 was found to be the most adequate method for OCS thermodynamic calculations. • Calculated hydrolysis yields decrease when temperature increases. • The isotopic effect is less significant than temperature or initial concentration dependences. - Abstract: Carbonyl sulphide is the predominant sulphur compound in the atmosphere, contributing to the formation of aerosol particles affecting global climate. Human activity has significantly increased its total amount since the beginning of the Industrial Revolution due to its presence in petroleum and coal, reason why it is necessary to understand and control its emissions. On the other hand, carbonyl sulphide is an undesired substance for catalysis in important industrial processes. Hydrolysis is the most promising among the different strategies to reduce its presence, giving as products carbon dioxide and hydrogen sulphide. In the present work, the mechanism of reaction of carbonyl sulphide hydrolysis process in gas phase was studied from 400 K to 1500 K, equilibrium constants were obtained and reaction yields were estimated, by means of composite quantum-computational methods. Good agreement with literature experimental results confirms the suitability of the chosen methods, specially CBS-QB3, in supporting the reaction mechanism, giving accurate equilibrium constant values, and obtaining realistic yields. The effect of isotopic substitution in OCS was also studied, from 300 K to 1500 K, being much less significant than temperature dependence.

Thermodynamical properties of dark energy

International Nuclear Information System (INIS)

Gong Yungui; Wang Bin; Wang Anzhong

2007-01-01

We have investigated the thermodynamical properties of dark energy. Assuming that the dark energy temperature T∼a -n and considering that the volume of the Universe enveloped by the apparent horizon relates to the temperature, we have derived the dark energy entropy. For dark energy with constant equation of state w>-1 and the generalized Chaplygin gas, the derived entropy can be positive and satisfy the entropy bound. The total entropy, including those of dark energy, the thermal radiation, and the apparent horizon, satisfies the generalized second law of thermodynamics. However, for the phantom with constant equation of state, the positivity of entropy, the entropy bound, and the generalized second law cannot be satisfied simultaneously

Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

Science.gov (United States)

Povinelli, Louis A.

2001-01-01

A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

A storage ring study of dissociative excitation and recombination of D3+

International Nuclear Information System (INIS)

Le Padellec, A.; Larson, Aa.; Semaniak, J.; Stroemholm, C.; Larsson, M.; Rosen, S.; Danared, H.; Peterson, J.R.

1998-01-01

Dissociative recombination and excitation of D 3 + have been studied in CRYRING, a heavy-ion storage ring at the Manne Siegbahn laboratory at Stockholm University. The measured cross section for dissociative recombination was used to deduce a 300 K rate constant of 2.7 x 10 -8 cm 3 s -1 . This is a factor of four smaller than the corresponding value for H 3 + measured earlier in CRYRING. Dissociative excitation into both the D and 2D channels (D + D or D 2 ) were studied. The 2D channel occurs at energies below threshold for the ion's dissociative states, which indicates that resonant enhanced dissociative excitation via autoionizing resonances takes place. No measurable effect could be observed for the dissociative recombination cross sections when an electric field of 30 V/cm was applied to the electron-ion interaction region. (orig.)

Universality of P−V criticality in horizon thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Hansen, Devin; Kubizňák, David [Perimeter Institute,31 Caroline St. N., Waterloo, Ontario, N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada)

2017-01-11

We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.

Universality of P−V criticality in horizon thermodynamics

International Nuclear Information System (INIS)

Hansen, Devin; Kubizňák, David; Mann, Robert B.

2017-01-01

We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.

Canonical operator formulation of nonequilibrium thermodynamics

International Nuclear Information System (INIS)

Mehrafarin, M.

1992-09-01

A novel formulation of nonequilibrium thermodynamics is proposed which emphasises the fundamental role played by the Boltzmann constant k in fluctuations. The equivalence of this and the stochastic formulation is demonstrated. The k → 0 limit of this theory yields the classical deterministic description of nonequilibrium thermodynamics. The new formulation possesses unique features which bear two important results namely the thermodynamic uncertainty principle and the quantisation of entropy production rate. Such a theory becomes indispensable whenever fluctuations play a significant role. (author). 7 refs

Comments Simplification of thermodynamic calculations through dimensionless entropies

International Nuclear Information System (INIS)

Pitzer, K.S.; Brewer, L.

1979-01-01

The advantages of using thermodynamic quantities divided by the gas constant (H/R, G/R, etc,) in calculations are described. It is recommended that thermodynamic tables be presented in this form, so that the entries are either dimensionless or in units of kelvins

Correlations between channel probabilities in collisional dissociation of D3+

International Nuclear Information System (INIS)

Abraham, S.; Nir, D.; Rosner, B.

1984-01-01

Measurements of the dissociation of D 3 + ions at 300--600 keV under single- and multiple-collision conditions in Ar- and H 2 -gas targets have been performed. A complete separation of all dissociation channels was achieved, including the neutral channels, which were resolved using a fine-mesh technique. Data analysis in the multiple-collision regime confirms the validity of the rate equations governing the charge exchange processes. In the single-collision region the analysis yields constant relations between channel probabilities. Data rearrangement shows probability factorization and suggests that collisional dissociation is a two-stage process, a fast electron exchange followed by rearrangement and branching to the exit channels

International thermodynamic tables of the fluid state propylene (propene)

CERN Document Server

Angus, S; De Reuck, K M

2013-01-01

International Thermodynamic Tables of the Fluid State - 7 Propylene (Propene) is a compilation of internationally agreed values of the equilibrium thermodynamic properties of propylene. This book is composed of three chapters, and begins with the presentation of experimental result of thermodynamic studies compared with the equations used to generate the tables. The succeeding chapter deals with correlating equations for thermodynamic property determination of propylene. The last chapter provides the tabulations of the propylene's thermodynamic properties and constants. This book will prove

Thermodynamic analysis of the Cu2S-Cu2Te system using dissociation pressure data

International Nuclear Information System (INIS)

Glazov, V.M.; Pashinkin, A.S.; Burkhanov, A.S.; Saleeva, N.M.

1978-01-01

The Knudsen effusive method has been used for studying the dissociation pressure in the Cu 2 S-Cu 2 Te system, and on the basis of the experimental data obtained, the tellurium activity in the system and the mixing energy have been calculated. The dissociation pressure of pure components and alloys containing 10, 30, 50, 70, and 90 mol% of copper telluride within the temperature range of 750-1200 deg C has been studied. A smooth character of the concentration dependence of tellurium activity is observed, which points to the formation of a continuous series of solid solutions in the Cu 2 S-Cu 2 Te system within the temperature range studied. The data on the mixing energy in the system show a good agreement of the values obtained from the dissociation pressure with those determined from the fusibility diagram. The results indicate that the system in question is described well within the framework of the model of regular solutions

A nonaqueous potentiometric titration study of the dissociation of t-butyl methacrylate-methacrylic acid copolymers.

Science.gov (United States)

Nakatani, Kiyoharu; Yamashita, Jun; Sekine, Tomomi; Toriumi, Minoru; Itani, Toshiro

2003-05-01

The dissociation of t-butyl methacrylate-methacrylic acid copolymers in dimethyl sulfoxide was analyzed by a nonaqueous potentiometric titration technique. The negative logarithm of the dissociation constant of the monomer unit of a methacrylic acid (MAA) monotonously increased with the increasing degree of dissociation corresponding to the titrant/MAA amount ratio, and was highly influenced by the copolymerization ratio. The results are discussed in terms of the suppression of the dissociation of MAA by a neighboring charged methacrylate anion unit.

Effect of transition metal-doped Ni(211) for CO dissociation: Insights from DFT calculations

Energy Technology Data Exchange (ETDEWEB)

Yang, Kuiwei; Zhang, Minhua [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China)

2017-03-31

Highlights: • Doping the step edge of Ni(211) with Fe or Ru observably enhances CO dissociation. • Rh doping is unfavorable for CO activation both kinetically and thermodynamically. • Two neat linear relations are proposed besides the Brønsted–Evans–Polanyi relation. • The differences of CO adsorption are rationalized via the Blyholder model. - Abstract: Density functional theory slab calculations were performed to investigate the adsorption and dissociation of CO over pure and M-doped Ni(211) (M = Fe, Co, Ru and Rh) with the aim to elucidate the effect of transition metal doping for CO activation. Doping the step edge of Ni(211) with Fe, Co and Ru is found to enhance the binding of CO in the initial state (IS) (in the sequence by the improvement degree: Fe > Ru > Co) as well as the co-adsorption of C and O in the final state (FS) (Ru > Fe > Co). In contrast, Rh doping is unfavorable both in the IS and in the FS. Analysis of the overall potential energy surfaces (PES) suggests CO dissociation is facilitated by Fe, Ru and Co doping both kinetically and thermodynamically, wherein Fe and Ru behave extraordinary. Interestingly, Fe substitute is slightly superior to Ru in kinetics whereas the contrary is the case in thermodynamics. Rh doping elevates the energy height from 0.97 eV on Ni(211) to 1.32 eV and releases 0.39 eV less heat relative to Ni(211), again manifesting a negative effect. Besides the classical Brønsted–Evans–Polanyi relationship, we put forward another two neat linear relations, which can well describe the feature of CO dissociation. The differences of CO adsorption and activation in the IS over pure and doped Ni(211) surfaces are rationalized via electronic structure analysis. The findings presented herein are expected to provide theoretical guidance for catalyst design and optimization in relevant processes.

High-temperature of thermodynamic properties of sodium

Energy Technology Data Exchange (ETDEWEB)

Padilla, A. Jr.

1977-01-01

The set of high-temperature thermodynamic properties for sodium in the two-phase and subcooled-liquid regions which was previously recommended, has been modified to incorporate recent experimental data. In particular, replacement of the previously estimated critical constants with experimentally-determined values has resulted in substantial differences in the region of the critical point. The following thermodynamic properties were determined: pressure, density, enthalpy, entropy, internal energy, compressibility (adiabatic and isothermal), thermal expansion coefficient, thermal pressure coefficient, and specific heat (constant-pressure and constant-volume). These properties were determined for the saturated liquid, saturated vapor, subcooled liquid, and superheated vapor. The superheated vapor properties are limited to low pressures and more work is required to extend them to higher pressures. The supercritical region was not investigated.

Model-independent determination of dissociation energies: method and applications

International Nuclear Information System (INIS)

Vogel, Manuel; Hansen, Klavs; Herlert, Alexander; Schweikhard, Lutz

2003-01-01

A number of methods are available for the purpose of extracting dissociation energies of polyatomic particles. Many of these techniques relate the rate of disintegration at a known excitation energy to the value of the dissociation energy. However, such a determination is susceptible to systematic uncertainties, mainly due to the unknown thermal properties of the particles and the potential existence of 'dark' channels, such as radiative cooling. These problems can be avoided with a recently developed procedure, which applies energy-dependent reactions of the decay products as an uncalibrated thermometer. Thus, it allows a direct measurement of dissociation energies, without any assumption on properties of the system or on details of the disintegration process. The experiments have been performed in a Penning trap, where both rate constants and branching ratios have been measured. The dissociation energies determined with different versions of the method yield identical values, within a small uncertainty

Use of Computed X-ray Tomographic Data for Analyzing the Thermodynamics of a Dissociating Porous Sand/Hydrate Mixture

Science.gov (United States)

Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

2002-02-28

X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation.

Use of computed X-ray tomographic data for analyzing the thermodynamics of a dissociating porous sand/hydrate mixture

International Nuclear Information System (INIS)

Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

2002-01-01

X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation

Critical behavior of the dielectric constant in asymmetric fluids.

Science.gov (United States)

Bertrand, C E; Sengers, J V; Anisimov, M A

2011-12-08

By applying a thermodynamic theory that incorporates the concept of complete scaling, we derive the asymptotic temperature dependence of the critical behavior of the dielectric constant above the critical temperature along the critical isochore and below the critical temperature along the coexistence curve. The amplitudes of the singular terms in the temperature expansions are related to the changes of the critical temperature and the critical chemical potential upon the introduction of an electric field. The results of the thermodynamic theory are then compared with the critical behavior implied by the classical Clausius-Mossotti approximation. The Clausius-Mossotti approximation fails to account for any singular temperature dependence of the dielectric constant above the critical temperature. Below the critical temperature it produces an apparent asymmetric critical behavior with singular terms similar to those implied by the thermodynamic theory, but with significantly different coefficients. We conclude that the Clausius-Mossotti approximation only can account for the observed asymptotic critical behavior of the dielectric constant when the dependence of the critical temperature on the electric field is negligibly small. © 2011 American Chemical Society

The Off-rate of Monomers Dissociating from Amyloid-β Protofibrils*

Science.gov (United States)

Grüning, Clara S. R.; Klinker, Stefan; Wolff, Martin; Schneider, Mario; Toksöz, Küpra; Klein, Antonia N.; Nagel-Steger, Luitgard; Willbold, Dieter; Hoyer, Wolfgang

2013-01-01

The interconversion of monomers, oligomers, and amyloid fibrils of the amyloid-β peptide (Aβ) has been implicated in the pathogenesis of Alzheimer disease. The determination of the kinetics of the individual association and dissociation reactions is hampered by the fact that forward and reverse reactions to/from different aggregation states occur simultaneously. Here, we report the kinetics of dissociation of Aβ monomers from protofibrils, prefibrillar high molecular weight oligomers previously shown to possess pronounced neurotoxicity. An engineered binding protein sequestering specifically monomeric Aβ was employed to follow protofibril dissociation by tryptophan fluorescence, precluding confounding effects of reverse or competing reactions. Aβ protofibril dissociation into monomers follows exponential decay kinetics with a time constant of ∼2 h at 25 °C and an activation energy of 80 kJ/mol, values typical for high affinity biomolecular interactions. This study demonstrates the high kinetic stability of Aβ protofibrils toward dissociation into monomers and supports the delineation of the Aβ folding and assembly energy landscape. PMID:24247242

Efficiency of an air-cooled thermodynamic cycle

International Nuclear Information System (INIS)

Bezborodov, Yu.A.; Bubnov, V.P.; Nesterenko, V.B.

1979-01-01

The application of air, nitrogen, helium and the chemically reacting N 2 O 4 reversible 2NO 2 reversible 2NO + O 2 system as working agents and coolants for a low capacity nuclear power plant is investigated. The above system due to its physico-chemical and thermo-physical properties allows both a gaseous cycle and a cycle with condensation. The analysis has shown that a thermodynamic air-cooled cycle with the dissociating nitrogen tetroxide in the temperature range from 500 to 600 deg C has an advantage over cycles with air and nitrogen. To identify the chemical reaction kinetics in the thermodynamic processes, thermodynamic calculations of the gas-liquid cycle with N 2 O 4 both with simple and intermediate heat regeneration at different pressures over hot side were performed. At gas pressures lower than 12 - 15 atm, the cycle with a simple regeneration is more effective, and at pressure increase, the cycle with an intermediate regeneration is preferable

Fundamental aspects of plasma chemical physics Thermodynamics

CERN Document Server

Capitelli, Mario; D'Angola, Antonio

2012-01-01

Fundamental Aspects of Plasma Chemical Physics - Thermodynamics develops basic and advanced concepts of plasma thermodynamics from both classical and statistical points of view. After a refreshment of classical thermodynamics applied to the dissociation and ionization regimes, the book invites the reader to discover the role of electronic excitation in affecting the properties of plasmas, a topic often overlooked by the thermal plasma community. Particular attention is devoted to the problem of the divergence of the partition function of atomic species and the state-to-state approach for calculating the partition function of diatomic and polyatomic molecules. The limit of ideal gas approximation is also discussed, by introducing Debye-Huckel and virial corrections. Throughout the book, worked examples are given in order to clarify concepts and mathematical approaches. This book is a first of a series of three books to be published by the authors on fundamental aspects of plasma chemical physics.  The next bo...

Apparent formation constants of Pu(IV) and Th(IV) with humic acids determined by solvent extraction method

Energy Technology Data Exchange (ETDEWEB)

Sasaki, T.; Aoyama, S.; Yoshida, H.; Kobayashi, T.; Takagi, I. [Tokyo Univ. (Japan). Dept. of Nuclear Engineering; Kulyako, Y.; Samsonov, M.; Miyasoedov, B. [Russian Academy of Sciences, Moscow (Russian Federation). V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI); Moriyama, H. [Kyoto Univ. (Japan). Research Reactor Inst.

2012-07-01

Apparent formation constants of Pu(IV) and Th(IV) with two kinds of humic acids were determined in 0.1 M NaClO{sub 4} at 25 C using a solvent extraction method with thenoyltrifluoroacetone in xylene. The acid dissociation constants of humic acids were also measured by potentiometric titration and used as the degree of dissociation for calculating the formation constants. The effect of solution conditions, such as the pH, the initial metal and humic acid concentrations, and the ionic strength, on the formation constants was examined. The obtained data were compared with the ones in the literature. (orig.)

Electron-impact dissociative ionization of CClF3 and CCl3F

International Nuclear Information System (INIS)

Martinez, Roberto; Sierra, Borja; Basterretxea, Francisco J.; Sanchez Rayo, Maria N.; Castano, Fernando

2006-01-01

A crossed-beam experiment of well characterized kinetic energy (KE) electrons and supersonic halomethanes CCl 3 F and CClF 3 in Ar carrier has been carried out in order to quantify the kinetic energy distributions (KEDs), the appearance energies (AEs) and the channels involved in the production of nascent ions. The ion KEDs were derived from the band profiles of the time-of-flight mass spectrum and the total KEDs computed using conservation laws. Heavier ions are created with KED peaked at thermal energies in contrast with low mass atoms or other fragments, where the distribution is broader and the maximum is at much higher energies. A discussion of the dissociative ionization pathways derived from the appearance energies, total average KEDs, thermodynamic enthalpies and computed electron dissociation energies is reported. The role of the vibrational and rotational energies into the dissociative processes is also discussed

Varying constants, black holes, and quantum gravity

International Nuclear Information System (INIS)

Carlip, S.

2003-01-01

Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

The Dual Role of Disorder on the Dissociation of Interfacial Charge Transfer Excitons

Science.gov (United States)

Shi, Liang; Lee, Chee-Kong; Willard, Adam

In organic-based photovoltaics (OPV), dissociation of neutral photo-excitations (i.e., Frenkel excitons) into free charge carriers requires the excitons to overcome binding energy that can significantly exceed thermal energies. The inability of bound charges to overcome this large binding energy has been implicated as a primary source of efficiency loss in OPVs. Despite the potential impact on the performance of organic solar cells much remains to be understood about the microscopic mechanism of exciton dissociation in OPV materials. Here we explore the role of static molecular disorder in mediating this charge dissociation process. Using a simple lattice model of exciton dynamics we demonstrate that random spatial variations in the energetic landscape can mitigate the effects of the exciton binding energy by lowering the free energy barrier. By considering the competition between this thermodynamic effect and the disorder-induced slowing of dissociation kinetics we demonstrate that exciton dissociation yields are expected to depend non-monotonically on the degree of static disorder. We conclude that a certain amount of molecular-scale disorder is desirable in order to optimize the performance of organic photovoltaic materials.

Ionic concentrations and hydration numbers of "supporting electrolytes"

Czech Academy of Sciences Publication Activity Database

Heyrovská, Rajalakshmi

2006-01-01

Roč. 18, č. 4 (2006), s. 351-361 ISSN 1040-0397 R&D Projects: GA MPO 1H-PK/42 Institutional research plan: CEZ:AV0Z40400503 Keywords : strong electrolytes * degrees of dissociation * solution thermodynamics * dissociation constant Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.444, year: 2006

Identification of Weak Acids and Bases by Titration with Primary Standards. A Modern Version of an Old Analytical Chemistry Experiment.

Science.gov (United States)

Thompson, Robert Q.

1988-01-01

Describes a laboratory exercise in which acid dissociation constants and molecular weights are extracted from sample data and the sample is identified. Emphasizes accurate volumetric work while bringing to practice the concepts of acid-base equilibria, activity coefficients, and thermodynamic constants. (CW)

Differential dissociation micromethod for the investigation of binding of metandrostenolone (Nerobol) to plasma proteins

Energy Technology Data Exchange (ETDEWEB)

Bojadzsieva, M.; Kocsar, L. (Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszseguegyi Kutato Intezet, Budapest (Hungary)); Kremmer, T. (Orszagos Onkologiai Intezet, Budapest (Hungary))

1985-01-01

A micromethod was developed to determine the binding of anabolic steroids to plasma proteins. The new procedure combines precipitation with ammonium sulphate and differential dissociation. The binding parameters (association constant, specific binding capacity) are calculated on the basis of dissociation curves of sup(3)H-metandrostenolone from the precipitated sexual binding globuline.

Spectroscopic constants and the potential energy curve of the iodine weakly bound 0+g state correlating with the I(2P1/2) + I(2P1/2) dissociation limit

International Nuclear Information System (INIS)

Akopyan, M E; Baturo, V V; Lukashov, S S; Poretsky, S A; Pravilov, A M

2013-01-01

The stepwise three-step three-colour aser excitation scheme and rotational as well as rovibrational energy transfer processes in the 0 + g state induced by collisions with He and Ar atoms are used for determination of rovibronic level energies of the weakly bound 0 + g state correlating with the I( 2 P 1/2 ) + I( 2 P 1/2 ) dissociation limit. Dunham coefficients of the state, Y i0 (i = 0–3), Y i1 (i = 0–3) and Y 02 for the v 0 g + = 0–16 and J 0 g + ≈ 14–135 ranges as well as the dissociation energy of the state, D e , and equilibrium I–I distance of the state, R e , are determined. The potential energy curve of the state constructed using these constants is also reported. (paper)

Measuring Boltzmann's Constant with Carbon Dioxide

Science.gov (United States)

Ivanov, Dragia; Nikolov, Stefan

2013-01-01

In this paper we present two experiments to measure Boltzmann's constant--one of the fundamental constants of modern-day physics, which lies at the base of statistical mechanics and thermodynamics. The experiments use very basic theory, simple equipment and cheap and safe materials yet provide very precise results. They are very easy and…

Differential dissociation micromethod for the investigation of binding of metandrostenolone (Nerobol) to plasma proteins

International Nuclear Information System (INIS)

Bojadzsieva, Milka; Kocsar, Laszlo; Kremmer, Tibor

1985-01-01

A micromethod was developed to determine the binding of anabolic streoids to plasma proteins. The new procedure combines precipitation with ammonium sulphate and differential dissociation. The binding parameters (association constant, specific binding capacity) are calculated on the basis of dissociation curves of sup(3)H-metandrostenolone from the precipitated sexual binding globuline. (L.E.)

Using electrophoretic mobility shift assays to measure equilibrium dissociation constants: GAL4-p53 binding DNA as a model system.

Science.gov (United States)

Heffler, Michael A; Walters, Ryan D; Kugel, Jennifer F

2012-01-01

An undergraduate biochemistry laboratory experiment is described that will teach students the practical and theoretical considerations for measuring the equilibrium dissociation constant (K(D) ) for a protein/DNA interaction using electrophoretic mobility shift assays (EMSAs). An EMSA monitors the migration of DNA through a native gel; the DNA migrates more slowly when bound to a protein. To determine a K(D) the amount of unbound and protein-bound DNA in the gel is measured as the protein concentration increases. By performing this experiment, students will be introduced to making affinity measurements and gain experience in performing quantitative EMSAs. The experiment describes measuring the K(D) for the interaction between the chimeric protein GAL4-p53 and its DNA recognition site; however, the techniques are adaptable to other DNA binding proteins. In addition, the basic experiment described can be easily expanded to include additional inquiry-driven experimentation. © 2012 by The International Union of Biochemistry and Molecular Biology. Copyright © 2012 Wiley Periodicals, Inc.

Excited-State N2 Dissociation Pathway on Fe-Functionalized Au.

Science.gov (United States)

Martirez, John Mark P; Carter, Emily A

2017-03-29

Localized surface plasmon resonances (LSPRs) offer the possibility of light-activated chemical catalysis on surfaces of strongly plasmonic metal nanoparticles. This technology relies on lower-barrier bond formation and/or dissociation routes made available through energy transfer following the eventual decay of LSPRs. The coupling between these decay processes and a chemical trajectory (nuclear motion, charge-transfer, intersystem crossing, etc.) dictates the availability of these alternative (possibly lower barrier) excited-state channels. The Haber-Bosch method of NH 3 synthesis from N 2 and H 2 is notoriously energy intensive. This is due to the difficulty of N 2 dissociation despite the overall reaction being thermodynamically favorable at ambient temperatures and pressures. LSPRs may provide means to improve the kinetics of N 2 dissociation via induced resonance electronic excitation. In this work, we calculate, via embedded n-electron valence second-order perturbation theory within the density functional embedding theory, the excited-state potential energy surfaces for dissociation of N 2 on an Fe-doped Au(111) surface. This metal alloy may take advantage simultaneously of the strong LSPR of Au and the catalytic activity of Fe toward N 2 dissociation. We find the ground-state dissociation activation energy to be 4.74 eV/N 2 , with Fe as the active site on the surface. Consecutive resonance energy transfers (RETs) may be accessed due to the availability of many electronically excited states with intermediate energies arising from the metal surface that may couple to states induced by the Fe-dopant and the adsorbate molecule, and crossing between excited states may effectively lower the dissociation barrier to 1.33 eV. Our work illustrates that large energetic barriers, prohibitive toward chemical reaction, may be overcome through multiple RETs facilitating an otherwise difficult chemical process.

General method and thermodynamic tables for computation of equilibrium composition and temperature of chemical reactions

Science.gov (United States)

Huff, Vearl N; Gordon, Sanford; Morrell, Virginia E

1951-01-01

A rapidly convergent successive approximation process is described that simultaneously determines both composition and temperature resulting from a chemical reaction. This method is suitable for use with any set of reactants over the complete range of mixture ratios as long as the products of reaction are ideal gases. An approximate treatment of limited amounts of liquids and solids is also included. This method is particularly suited to problems having a large number of products of reaction and to problems that require determination of such properties as specific heat or velocity of sound of a dissociating mixture. The method presented is applicable to a wide variety of problems that include (1) combustion at constant pressure or volume; and (2) isentropic expansion to an assigned pressure, temperature, or Mach number. Tables of thermodynamic functions needed with this method are included for 42 substances for convenience in numerical computations.

Thermodynamic Analysis of Chemically Reacting Mixtures-Comparison of First and Second Order Models.

Science.gov (United States)

Pekař, Miloslav

2018-01-01

Recently, a method based on non-equilibrium continuum thermodynamics which derives thermodynamically consistent reaction rate models together with thermodynamic constraints on their parameters was analyzed using a triangular reaction scheme. The scheme was kinetically of the first order. Here, the analysis is further developed for several first and second order schemes to gain a deeper insight into the thermodynamic consistency of rate equations and relationships between chemical thermodynamic and kinetics. It is shown that the thermodynamic constraints on the so-called proper rate coefficient are usually simple sign restrictions consistent with the supposed reaction directions. Constraints on the so-called coupling rate coefficients are more complex and weaker. This means more freedom in kinetic coupling between reaction steps in a scheme, i.e., in the kinetic effects of other reactions on the rate of some reaction in a reacting system. When compared with traditional mass-action rate equations, the method allows a reduction in the number of traditional rate constants to be evaluated from data, i.e., a reduction in the dimensionality of the parameter estimation problem. This is due to identifying relationships between mass-action rate constants (relationships which also include thermodynamic equilibrium constants) which have so far been unknown.

Measurements of thermodynamic constants of transuranic compounds to predict their geochemistry: Carbonate complexation of Np(V) and Am(III), hydrolysis of Pu(VI) and AM(III)

International Nuclear Information System (INIS)

Vitorge, P.

1984-02-01

This work is a part of a project to build a waste disposal and to model the behaviour of the radioactive elements. The contribution consists in the prediction of the geochemistry of actinides and the measurement of thermodynamic equilibrium constants, solubility products and redox potentials (E) used in the migration model. It has shown that literature can provide values for some of these constants and proposed theoretical E(pH) diagrams and solubilities of U, Np, Pu, Am. All transport will occur essentially in the aqueous phase leaching the repository site, where hydrolysis and carbonate complexation are important chemical reactions. The hydrolysis and carbonate complexation constants have already been reviewed. The experimental results are compared with the literature data which are usually chosen to predict the solubilities and the proportions of the different forms of these actinides in natural groundwaters

Black hole chemistry: thermodynamics with Lambda

International Nuclear Information System (INIS)

Kubizňák, David; Mann, Robert B; Teo, Mae

2017-01-01

We review recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. In this approach, the mass of the black hole is no longer regarded as internal energy, rather it is identified with the chemical enthalpy. This leads to an extended dictionary for black hole thermodynamic quantities; in particular a notion of thermodynamic volume emerges for a given black hole spacetime. This volume is conjectured to satisfy the reverse isoperimetric inequality—an inequality imposing a bound on the amount of entropy black hole can carry for a fixed thermodynamic volume. New thermodynamic phase transitions naturally emerge from these identifications. Namely, we show that black holes can be understood from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. We also review the recent attempts at extending the AdS/CFT dictionary in this setting, discuss the connections with horizon thermodynamics, applications to Lifshitz spacetimes, and outline possible future directions in this field. (topical review)

THERMODYNAMIC PARAMETERS OF LEAD SULFIDE CRYSTALS IN THE CUBIC PHASE

Directory of Open Access Journals (Sweden)

T. O. Parashchuk

2016-07-01

Full Text Available Geometric and thermodynamic parameters of cubic PbS crystals were obtained using the computer calculations of the thermodynamic parameters within density functional theory method DFT. Cluster models for the calculation based on the analysis of the crystal and electronic structure. Temperature dependence of energy ΔE and enthalpy ΔH, Gibbs free energy ΔG, heat capacity at constant pressure CP and constant volume CV, entropy ΔS were determined on the basis of ab initio calculations of the crystal structure of molecular clusters. Analytical expressions of temperature dependences of thermodynamic parameters which were approximated with quantum-chemical calculation points have been presented. Experimental results compared with theoretically calculated data.

Dissociation and psychosis in dissociative identity disorder and schizophrenia.

Science.gov (United States)

Laddis, Andreas; Dell, Paul F

2012-01-01

Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

Determination of thermodynamic affinities of various polar olefins as hydride, hydrogen atom, and electron acceptors in acetonitrile.

Science.gov (United States)

Cao, Ying; Zhang, Song-Chen; Zhang, Min; Shen, Guang-Bin; Zhu, Xiao-Qing

2013-07-19

A series of 69 polar olefins with various typical structures (X) were synthesized and the thermodynamic affinities (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the polar olefins obtaining hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the polar olefins (X(•-)) obtaining protons and hydrogen atoms, and the thermodynamic affinities of the hydrogen adducts of the polar olefins (XH(•)) obtaining electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The pure C═C π-bond heterolytic and homolytic dissociation energies of the polar olefins (X) in acetonitrile and the pure C═C π-bond homolytic dissociation energies of the radical anions of the polar olefins (X(•-)) in acetonitrile were estimated. The remote substituent effects on the six thermodynamic affinities of the polar olefins and their related reaction intermediates were examined using the Hammett linear free-energy relationships; the results show that the Hammett linear free-energy relationships all hold in the six chemical and electrochemical processes. The information disclosed in this work could not only supply a gap of the chemical thermodynamics of olefins as one class of very important organic unsaturated compounds but also strongly promote the fast development of the chemistry and applications of olefins.

Thermodynamic implications of the gravitationally induced particle creation scenario

Energy Technology Data Exchange (ETDEWEB)

Saha, Subhajit [Indian Institute of Science Education and Research Kolkata, Department of Physical Sciences, Mohanpur, West Bengal (India); Mondal, Anindita [S N Bose National Centre for Basic Sciences, Department of Astrophysics and Cosmology, Kolkata, West Bengal (India)

2017-03-15

A rigorous thermodynamic analysis has been done as regards the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate Γ. Assuming a perfect fluid equation of state p = (γ - 1)ρ with (2)/(3) ≤ γ ≤ 2, the first law, the generalized second law (GSL), and thermodynamic equilibrium have been studied, and an expression for the total entropy (i.e., horizon entropy plus fluid entropy) has been obtained which does not contain Γ explicitly. Moreover, a lower bound for the fluid temperature T{sub f} has also been found which is given by T{sub f} ≥ 8 (((3γ)/(2)-1)/((2)/(γ)-1)) H{sup 2}. It has been shown that the GSL is satisfied for (Γ)/(3H) ≤ 1. Further, when Γ is constant, thermodynamic equilibrium is always possible for (1)/(2) < (Γ)/(3H) < 1, while for (Γ)/(3H) ≤ min {(1)/(2), (2γ-2)/(3γ-2)} and (Γ)/(3H) ≥ 1, equilibrium can never be attained. Thermodynamic arguments also lead us to believe that during the radiation phase, Γ ≤ H. When Γ is not a constant, thermodynamic equilibrium holds if H ≥ (27)/(4) γ{sup 2}H{sup 3} (1-(Γ)/(3H)){sup 2}, however, such a condition is by no means necessary for the attainment of equilibrium. (orig.)

Thermodynamic implications of the gravitationally induced particle creation scenario

International Nuclear Information System (INIS)

Saha, Subhajit; Mondal, Anindita

2017-01-01

A rigorous thermodynamic analysis has been done as regards the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate Γ. Assuming a perfect fluid equation of state p = (γ - 1)ρ with (2)/(3) ≤ γ ≤ 2, the first law, the generalized second law (GSL), and thermodynamic equilibrium have been studied, and an expression for the total entropy (i.e., horizon entropy plus fluid entropy) has been obtained which does not contain Γ explicitly. Moreover, a lower bound for the fluid temperature T f has also been found which is given by T f ≥ 8 (((3γ)/(2)-1)/((2)/(γ)-1)) H 2 . It has been shown that the GSL is satisfied for (Γ)/(3H) ≤ 1. Further, when Γ is constant, thermodynamic equilibrium is always possible for (1)/(2) < (Γ)/(3H) < 1, while for (Γ)/(3H) ≤ min {(1)/(2), (2γ-2)/(3γ-2)} and (Γ)/(3H) ≥ 1, equilibrium can never be attained. Thermodynamic arguments also lead us to believe that during the radiation phase, Γ ≤ H. When Γ is not a constant, thermodynamic equilibrium holds if H ≥ (27)/(4) γ 2 H 3 (1-(Γ)/(3H)) 2 , however, such a condition is by no means necessary for the attainment of equilibrium. (orig.)

Experimental determination of thermodynamic equilibrium in biocatalytic transamination.

Science.gov (United States)

Tufvesson, Pär; Jensen, Jacob S; Kroutil, Wolfgang; Woodley, John M

2012-08-01

The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones. Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore, in this communication we suggest a simple experimental methodology which we hope will stimulate more accurate determination of thermodynamic equilibria when reporting the results of transaminase-catalyzed reactions in order to increase understanding of the relationship between substrate and product molecular structure on reaction thermodynamics. Copyright © 2012 Wiley Periodicals, Inc.

Solution phase thermodynamics of strong electrolytes based on ionic concentrations, hydration numbers and volumes of dissolved entities

Czech Academy of Sciences Publication Activity Database

Heyrovská, Raji

2013-01-01

Roč. 24, č. 6 (2013), s. 1895-1901 ISSN 1040-0400 Institutional support: RVO:68081707 Keywords : Solution thermodynamics * Aqueous electrolytes * Partial electrolytic dissociation Subject RIV: BO - Biophysics Impact factor: 1.900, year: 2013

Thermodynamic and kinetic studies of As2O3 toxicological effects on human insulin in generation diabetes mellitus

Science.gov (United States)

Mohsennia, Mohsen; Motaharinejad, Atieh; Rafiee-Pour, Hossain-Ali; Torabbeigi, Marzieh

2017-12-01

The interaction of arsenic trioxide with human insulin was investigated by circular dichroism (CD), cyclic voltammetry and electrophoresis techniques. The interfacial behavior of insulin in presence of As2O3 onto the Ag electrode surface was studied at 310 K in phosphate buffer solution (PBS). According to Far-UV CD spectroscopy results, As2O3 caused to decrease in structural compactness and variety of alpha helix into beta structures. Near-UV CD indicated that As2O3 dissociates disulfide linkage in insulin structure. The kinetic parameters, including charge-transfer coefficient and apparent heterogeneous electron transfer rate constant were also determined. The thermodynamic parameters of insulin denaturation in presence of arsenic trioxide were calculated and reported. The obtained results indicated strong adsorption of insulin in presence of arsenic trioxide onto the Ag surface via chemisorptions.

Thermodynamic properties of α-uranium

International Nuclear Information System (INIS)

Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao

2016-01-01

The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T"3 power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.

Thermodynamic properties of α-uranium

Energy Technology Data Exchange (ETDEWEB)

Ren, Zhiyong; Wu, Jun; Ma, Rong; Hu, Guichao; Luo, Chao, E-mail: luochaoboss@sohu.com

2016-11-15

The lattice constants and equilibrium atomic volume of α-uranium were calculated by Density Functional Theory (DFT). The first principles calculation results of the lattice for α-uranium are in agreement with the experimental results well. The thermodynamic properties of α-uranium from 0 to 900 K and 0–100 GPa were calculated with the quasi-harmonic Debye model. Volume, bulk modulus, entropy, Debye temperature, thermal expansion coefficient and the heat capacity of α-uranium were calculated. The calculated results show that the bulk modulus and Debye temperature increase with the increasing pressure at a given temperature while decreasing with the increasing temperature at a given pressure. Volume, entropy, thermal expansion coefficient and the heat capacity decrease with the increasing pressure while increasing with the increasing temperature. The theoretical results of entropy, Debye temperature, thermal expansion coefficient and the heat capacity show good agreement with the general trends of the experimental values. The constant-volume heat capacity shows typical Debye T{sup 3} power-law behavior at low temperature limit and approaches to the classical asymptotic Dulong-Petit limit at high temperature limit. - Highlights: • Thermodynamic properties of α-U were predicted systematically with quasi-harmonic Debye model. • Summarizations of the corresponding experimental and theoretical results have been made for the EOS and other thermodynamic parameters. • The calculated thermodynamic properties show good agreement with the experimental results in general trends.

Thermodynamic properties of UF sub 6 measured with a ballistic piston compressor

Science.gov (United States)

Sterritt, D. E.; Lalos, G. T.; Schneider, R. T.

1973-01-01

From experiments performed with a ballistic piston compressor, certain thermodynamic properties of uranium hexafluoride were investigated. Difficulties presented by the nonideal processes encountered in ballistic compressors are discussed and a computer code BCCC (Ballistic Compressor Computer Code) is developed to analyze the experimental data. The BCCC unfolds the thermodynamic properties of uranium hexafluoride from the helium-uranium hexafluoride mixture used as the test gas in the ballistic compressor. The thermodynamic properties deduced include the specific heat at constant volume, the ratio of specific heats for UF6, and the viscous coupling constant of helium-uranium hexafluoride mixtures.

Theoretical investigation of the thermodynamic properties of metallic thin films

International Nuclear Information System (INIS)

Hung, Vu Van; Phuong, Duong Dai; Hoa, Nguyen Thi; Hieu, Ho Khac

2015-01-01

The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks

Theoretical investigation of the thermodynamic properties of metallic thin films

Energy Technology Data Exchange (ETDEWEB)

Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)

2015-05-29

The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.

Reaction constants, in cyclohexane, of lauryl-amines with tetrabromo-phenolphthalein magenta E acid

International Nuclear Information System (INIS)

Perez, J.J.

1966-11-01

Trilauryl amine is an extracting agent used for plutonium purification. Its main degradation product is di-laurylamine. The titration of this impurity is carried out by spectro-colorimetry in cyclohexane using bromophtalein Magenta E as coloured acid indicator. The reported dissociation constants for alcoylammonium salts are too closed to lead to a discrimination between secondary and tertiary amines. The present spectrophotometric study shows that the ratios of various dissociation constants for bromophtalein Magenta E salts are notably different from those for salts of simple coloured acids like 2,4 dinitro phenol. The structural changes accompanying the colorations are discussed in order to explain this phenomenon. (author) [fr

Barrierless association of CF2 and dissociation of C2F4 by variational transition-state theory and system-specific quantum Rice–Ramsperger–Kassel theory

Science.gov (United States)

Bao, Junwei Lucas; Zhang, Xin

2016-01-01

Bond dissociation is a fundamental chemical reaction, and the first principles modeling of the kinetics of dissociation reactions with a monotonically increasing potential energy along the dissociation coordinate presents a challenge not only for modern electronic structure methods but also for kinetics theory. In this work, we use multifaceted variable-reaction-coordinate variational transition-state theory (VRC-VTST) to compute the high-pressure limit dissociation rate constant of tetrafluoroethylene (C2F4), in which the potential energies are computed by direct dynamics with the M08-HX exchange correlation functional. To treat the pressure dependence of the unimolecular rate constants, we use the recently developed system-specific quantum Rice–Ramsperger–Kassel theory. The calculations are carried out by direct dynamics using an exchange correlation functional validated against calculations that go beyond coupled-cluster theory with single, double, and triple excitations. Our computed dissociation rate constants agree well with the recent experimental measurements. PMID:27834727

Thermodynamic Geometry and Hawking Radiation

CERN Document Server

Bellucci, S

2010-01-01

This work explores the role of thermodynamic fluctuations in the two parameter Hawking radiating black hole configurations. The system is characterized by an ensemble of arbitrary mass and radiation frequency of the black holes. In the due course of the Hawking radiations, we find that the intrinsic geometric description exhibits an intriguing set of exact pair correction functions and global correlation lengths. We investigate the nature of the constant amplitude radiation and find that it's not stable under fluctuations of the mass and frequency. Subsequently, the consideration of the York model decreasing amplitude radiation demonstrates that thermodynamic fluctuations are globally stable in the small frequency region. In connection with quantum gravity refinements, we take an account of the logarithmic correction into the constant amplitude and York amplitude over the Hawking radiation. In both considerations, we notice that the nature of the possible parametric fluctuations may precisely be ascertained w...

DFT Study of Azole Corrosion Inhibitors on Cu2O Model of Oxidized Copper Surfaces: II. Lateral Interactions and Thermodynamic Stability

Directory of Open Access Journals (Sweden)

Dunja Gustinčič

2018-05-01

Full Text Available The adsorption of imidazole, triazole, and tetrazole—used as simple models of azole corrosion inhibitors—on various Cu 2 O(111- and Cu 2 O(110-type surfaces was characterized using density functional theory (DFT calculations with the focus on lateral intermolecular interactions and the thermodynamic stability of various adsorption structures. To this end, an ab initio thermodynamics approach was used to construct two-dimensional phase diagrams for all three molecules. The impact of van der Waals dispersion interactions on molecular adsorption bonding was also addressed. Lateral intermolecular interactions were found to be the most repulsive for imidazole and the least for tetrazole, for which they are usually even slightly attractive. Both non-dissociative and dissociative adsorption modes were considered and although dissociated molecules bind to surfaces more strongly, none of the considered structures that involve dissociated molecules appear on the phase diagrams. Our results show that the three azole molecules display a strong tendency to preferentially adsorb at reactive coordinatively unsaturated (CUS Cu surface sites and stabilize them. According to the calculated phase diagrams for Cu 2 O(111-type surfaces, the three azole molecules adsorb to specific CUS sites, designated as Cu CUS , under all conditions at which molecular adsorption is stable. This tentatively suggests that their corrosion inhibition capability may stem, at least in part, from their ability to passivate reactive surface sites. We further comment on a specific drawback due to neglect of configurational entropy that is usually utilized within the ab initio thermodynamics approach. We analyze the issue for Langmuir and Frumkin adsorption models and show that when configurational entropy is neglected, the ab initio thermodynamics approach is too hasty to predict phase-transition like behavior.

Thermodynamic properties of potassium chloride aqueous solutions

Science.gov (United States)

Zezin, Denis; Driesner, Thomas

2017-04-01

Potassium chloride is a ubiquitous salt in natural fluids, being the second most abundant dissolved salt in many geological aqueous solutions after sodium chloride. It is a simple solute and strong electrolyte easily dissociating in water, however the thermodynamic properties of KCl aqueous solutions were never correlated with sufficient accuracy for a wide range of physicochemical conditions. In this communication we propose a set of parameters for a Pitzer-type model which allows calculation of all necessary thermodynamic properties of KCl solution, namely excess Gibbs free energy and derived activity coefficient, apparent molar enthalpy, heat capacity and volume, as well as osmotic coefficient and activity of water in solutions. The system KCl-water is one of the best studied aqueous systems containing electrolytes. Although extensive experimental data were collected for thermodynamic properties of these solutions over the years, the accurate volumetric data became available only recently, thus making possible a complete thermodynamic formulation including a pressure dependence of excess Gibbs free energy and derived properties of the KCl-water liquids. Our proposed model is intended for calculation of major thermodynamic properties of KCl aqueous solutions at temperatures ranging from freezing point of a solution to 623 K, pressures ranging from saturated water vapor up to 150 MPa, and concentrations up to the salt saturation. This parameterized model will be further implemented in geochemical software packages and can facilitate the calculation of aqueous equilibrium for reactive transport codes.

Stability of black holes based on horizon thermodynamics

Directory of Open Access Journals (Sweden)

Meng-Sen Ma

2015-12-01

Full Text Available On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss–Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables E, P, V, T, S. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, P=P(V,T. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that P>0 is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss–Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.

Variable-speed-of-light cosmology and second law of thermodynamics

International Nuclear Information System (INIS)

Youm, Donam

2002-01-01

We examine whether cosmologies with a varying speed of light (VSL) are compatible with the second law of thermodynamics. We find that the VSL cosmology with a varying fundamental constant is severely constrained by the second law of thermodynamics, whereas the bimetric cosmological models are less constrained

Variable-speed-of-light cosmology and second law of thermodynamics

International Nuclear Information System (INIS)

Youm, Donam

2002-03-01

We examine whether the cosmologies with varying speed of light (VSL) are compatible with the second law of thermodynamics. We find that the VSL cosmology with varying fundamental constant is severely constrained by the second law of thermodynamics, whereas the bimetric cosmological models are less constrained. (author)

Thermodynamic Study of Inclusion Interactions between Gemini ...

African Journals Online (AJOL)

NICO

2014-11-25

Nov 25, 2014 ... Xiaomei Qiu*. College of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, China. E-mail: ... Introduction. Cyclodextrins (CD) are ... mine the thermodynamic parameters (stoichiometry, association constant ...

Thermodynamics and stability of hyperbolic charged black holes

International Nuclear Information System (INIS)

Cai Ronggen; Wang Anzhong

2004-01-01

In AdS space the black hole horizon can be a hypersurface with a positive, zero, or negative constant curvature, resulting in different horizon topology. Thermodynamics and stability of black holes in AdS spaces are quite different for different horizon curvatures. In this paper we study thermodynamics and stability of hyperbolic charged black holes with negative constant curvature horizon in the grand canonical ensemble and canonical ensemble, respectively. They include hyperbolic Reissner-Nordstroem black holes in arbitrary dimensions and hyperbolic black holes in the D=5,4,7 gauged supergravities. It is found that associated Gibbs free energies are always negative, which implies that these black hole solutions are globally stable and the black hole phase is dominant in the grand canonical ensemble, but there is a region in the phase space where the black hole is not locally thermodynamically stable with a negative heat capacity for a given gauge potential. In the canonical ensemble, the Helmholtz free energies are not always negative and heat capacities with fixed electric charge are not always positive, which indicates that the Hawking-Page phase transition may happen and black holes are not always locally thermodynamically stable

Resonances in dissociative recombination: Trends and patterns

Energy Technology Data Exchange (ETDEWEB)

Orel, A E; Ngassam, V; Royal, J [Department of Applied Science, University of California, Davis (United States); Roos, J B; Larson, A, E-mail: aeorel@ucdavis.ed [Department of Theoretical Chemistry, Royal Institute of Technology, Stockholm (Sweden)

2009-11-15

In dissociative recombination, the kinetic energy of the incident electron is transferred into excitation of the electrons of the target ion and then into kinetic energy of the fragments. In general, this proceeds via a resonance where the electron is temporarily trapped by the ion, leading to efficient energy transfer. The study of dissociative recombination is the study of these resonances, Rydberg states converging to the ground and excited states of the ion. For a number of systems, we have studied the electronic states involved in dissociative recombination, including the ground and excited states of the ion, the resonant states and the bound Rydberg states of the system, by combining electron scattering calculations with multi-reference configuration interaction quantum chemistry calculations. We will report on trends and patterns in these resonance states. We will discuss studies of dissociative recombination of the rare-gas ions, moving down the periodic table from He{sup +}{sub 2} to Ne{sup +}{sub 2} to Ar{sup +}{sub 2}, where the ground electronic state of the ion is constant, but its polarizability increases. We will also present results on isoelectronic polyatomic systems, such as HCO{sup +} and HCNH{sup +}, as well as the effects of changing the electronic structure slightly such as HCN{sup +}/HNC{sup +} and H{sub 2}CO{sup +}.

Thermodynamics of asymptotically safe theories

DEFF Research Database (Denmark)

Rischke, Dirk H.; Sannino, Francesco

2015-01-01

We investigate the thermodynamic properties of a novel class of gauge-Yukawa theories that have recently been shown to be completely asymptotically safe, because their short-distance behaviour is determined by the presence of an interacting fixed point. Not only do all the coupling constants freeze...

Rate coefficients for low-energy electron dissociative attachment to molecular hydrogen

International Nuclear Information System (INIS)

Horacek, J.; Houfek, K.; Cizek, M.; Murakami, I.; Kato, T.

2003-02-01

Calculation of rate constants for dissociative electron attachment to molecular hydrogen is reported. The calculation is based on an improved nonlocal resonance model of Cizek, Horacek and Domcke which takes fully into account the nonlocality of the resonance dynamics and uses potentials with correct asymptotic forms. The rate constants are calculated for all quantum numbers v and J of the target molecules and for electron temperature in the range 0-30000 K. (author)

Photodissociation constant of NO2

International Nuclear Information System (INIS)

Nootebos, M.A.; Bange, P.

1992-01-01

The velocity of the dissociation of NO 2 into ozone and NO mainly depends on the ultraviolet sunlight quantity, and with that the cloudiness. A correct value for this reaction constant is important for the accurate modelling of O 3 - and NO 2 -concentrations in plumes of electric power plants, in particular in the case of determination of the amount of photochemical summer smog. An advanced signal processing method (deconvolution, correlation) was applied on the measurements. The measurements were carried out from aeroplanes

JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes. Selection of thermodynamic data of molybdenum

International Nuclear Information System (INIS)

Kitamura, Akira; Kirishima, Akira; Saito, Takumi; Shibutani, Sanae; Tochiyama, Osamu

2010-06-01

Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level radioactive and TRU wastes, the selection of the thermodynamic data on the inorganic compounds and complexes of molybdenum were carried out. We focused to select thermodynamic data of aqueous species and compounds which could form under repository conditions for the disposal of radioactive wastes, i.e. relatively low concentration of molybdenum and from near neutral through alkaline conditions. Selection of thermodynamic data was based on the guidelines by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development (OECD/NEA). Extensive literature survey was performed and all the obtained articles were carefully reviewed to select the thermodynamic data for molybdenum. Thermodynamic data at 25degC and zero ionic strength were determined from accepted thermodynamic data which were considered to be reliable. We especially paid attention to select formation constant of molybdate ion (MoO 4 2- ) with hydrogen ion (H + ) in detail. This is the first report in showing selection of thermodynamic data for molybdenum with detailed reviewing process. (author)

Extrinsic and intrinsic curvatures in thermodynamic geometry

Energy Technology Data Exchange (ETDEWEB)

Hosseini Mansoori, Seyed Ali, E-mail: shossein@bu.edu [Department of Physics, Boston University, 590 Commonwealth Ave., Boston, MA 02215 (United States); Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sharifian, Elham, E-mail: e.sharifian@ph.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2016-08-10

We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.

Extrinsic and intrinsic curvatures in thermodynamic geometry

International Nuclear Information System (INIS)

Hosseini Mansoori, Seyed Ali; Mirza, Behrouz; Sharifian, Elham

2016-01-01

We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.

Synthesis, crystal structure, DFT studies, acid dissociation constant, and antimicrobial activity of methyl 2-(4-chlorophenyl)-7a-((4-chlorophenyl)carbamothioyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate

Science.gov (United States)

Nural, Yahya; Gemili, Muge; Seferoglu, Nurgul; Sahin, Ertan; Ulger, Mahmut; Sari, Hayati

2018-05-01

A novel bicyclic thiohydantoin fused to pyrrolidine compound, methyl 2-(4-chlorophenyl)-7a-((4-chlorophenyl)carbamothioyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate, was synthesized by the cyclization reaction of dimethyl 5,5-diphenylpyrrolidine-2,4-dicarboxylate and 4-chlorophenyl isothiocyanate in the presence of 4-(dimethylamino)pyridine to form methyl 2-(4-chlorophenyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate with concomitant addition reaction of the 4-chlorophenyl isothiocyanate in 79% yield. The structural characterization was performed by NMR, FT-IR, MS and HRMS techniques, and the stereochemistry of the compound was determined by single crystal X-ray diffraction study. In addition, the molecular structure and 1H and 13C NMR chemical shifts of the compound were obtained with the density functional theory and Hartree-Fock calculations. Acid dissociation constants of the compound were determined using potentiometric titration method in 25% (v/v) dimethyl sulfoxide-water hydroorganic solvent at 25 ± 0.1 °C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Four acid dissociation constants were obtained for the compound, and we suggest that these acid dissociation constants are related to the NH, for two groups of enthiols and enol groups. Antimicrobial activity study was performed against S. aureus, B. subtilis, A. hydrophila, E. coli and A. baumannii as bacterial standard strains, and against M. tuberculosis H37Rv as mycobacterial strain. The compound exhibited antibacterial activity in the range of 31.25-62.5 μg/mL, and antimycobacterial activity with a MIC value of 40 μg/mL against the indicated strains.

In situ generation of a hydroxyl radical by nanoporous activated carbon derived from rice husk for environmental applications: kinetic and thermodynamic constants.

Science.gov (United States)

Karthikeyan, S; Sekaran, G

2014-03-07

The objective of this investigation is to evaluate the hydroxyl radical (˙OH) generation using nanoporous activated carbon (NPAC), derived from rice husk, and dissolved oxygen in water. The in situ production of the ˙OH radical was confirmed through the DMPO spin trapping method in EPR spectroscopy and quantitative determination by a deoxyribose assay procedure. NPAC served as a heterogeneous catalyst to degrade 2-deoxy-d-ribose (a reference compound) using hydroxyl radical generated from dissolved oxygen in water at temperatures in the range 313-373 K and pH 6, with first order rate constants (k = 9.2 × 10(-2) min(-1), k = 1.2 × 10(-1) min(-1), k = 1.3 × 10(-1) min(-1) and k = 1.68 × 10(-1) min(-1)). The thermodynamic constants for the generation of hydroxyl radicals by NPAC and dissolved oxygen in water were ΔG -1.36 kJ mol(-1) at 313 K, ΔH 17.73 kJ mol(-1) and ΔS 61.01 J mol(-1) K(-1).

A Study of Universal Thermodynamics in Brane World Scenario

International Nuclear Information System (INIS)

Mitra, Saugata; Saha, Subhajit; Chakraborty, Subenoy

2015-01-01

A study of Universal thermodynamics is done in the framework of RSII brane model and DGP brane scenario. The Universe is chosen as FRW model bounded by apparent or event horizon. Assuming extended Hawking temperature on the horizon, the unified first law is examined for perfect fluid (with constant equation of state) and Modified Chaplygin Gas model. As a result there is a modification of Bekenstein entropy on the horizons. Further the validity of the generalized second law of thermodynamics and thermodynamical equilibrium are also investigated

Kinetics and mechanism of the dissociation of chlorophyll and its metalloanalogues in proton-donating media

International Nuclear Information System (INIS)

Berezin, B.D.; Drobysheva, A.N.; Karmanova, L.P.

1976-01-01

The kinetics of the dissociation of chlorophyll a and its metalloanalogues (Zn 2+ and Cd 2+ complexes of chlorophyllic acid) have been investigated in t-butyl alcohol-trichloracetic acid mixtures. The dissociation reaction is kinetically firts-order with respect to the complex. The rate constants and the activation energies and entropies for the dissociation reaction have been calculated. In order to determine the order of the reaction with respect to the protogenic species, a study was made of the ionisation of m-nitroaniline in t-butyl alcohol at 25 0 C in the trichloroacetic acid concentration range from 0.15 to 4.75 M. The dissociation reaction of chlorophyll and its zinc-containing metalloanalogue has been shown to be of second order with respect to the solvated proton. The cadmium complex dissociates by a second-order reaction with respect to trichloroacetic acid

The eΠ3g state of C2: A pathway to dissociation

Science.gov (United States)

Welsh, B. A.; Krechkivska, O.; Nauta, K.; Bacskay, G. B.; Kable, S. H.; Schmidt, T. W.

2017-07-01

The lowest 13 vibrational levels, v = 0-12, of the eΠ3g state of the C2 molecule have been measured by laser-induced fluorescence of new bands of the Fox-Herzberg system. The newly observed levels, v = 5-12, which span the eΠ3g electronic state up to and beyond the first dissociation threshold of C2, were analyzed to afford highly accurate molecular constants, including band origins, and rotational and spin-orbit constants. The spin-orbit coupling constants of the previously published lowest five levels are revised in sign and magnitude, requiring an overhaul of previously published molecular constants. The analysis is supported by high level ab initio calculations. Lifetimes of all observed levels were recorded and found to be in excellent agreement with ab initio predicted values up to v = 11. v = 12 was found to exhibit a much reduced lifetime and fluorescence quantum yield, which is attributed to the onset of predissociation. This brackets the dissociation energy of ground state XΣ+1g C2 between 6.1803 and 6.2553 eV, in agreement with the Active Thermochemical Tables.

Yeast hexokinase: substrate-induced association--dissociation reactions in the binding of glucose to hexokinase P-II.

Science.gov (United States)

Hoggett, J G; Kellett, G L

1976-06-15

A method is described for the purification of native hexokinases P-I and P-II from yeast using preparative isoelectric focussing to separate the isozymes. The binding of glucose to hexokinase P-II, and the effect of this on the monomer--dimer association--dissociation reaction have been investigated quantitatively by a combination of titrations of intrinsic protein fluorescence and equilibrium ultracentrifugation. Association constants for the monomer-dimer reaction decreased with increasing pH, ionic strength and concentration of glucose. Saturating concentrations of glucose did not bring about complete dissociation of the enzyme showing that both sites were occupired in the dimer. At pH 8.0 and high ionic strength, where the enzyme existed as monomer, the dissociation constant of the enzyme-glucose complex was 3 X 10(-4) mol 1(-1) and was independent of the concentration of enzyme. Binding to the dimeric form at low pH and ionic strength (I=0.02 mol 1(-1), pH less than 7.5) was also independent of enzyme concentration (in the range 10-1000 mug ml-1) but was much weaker. The process could be described by a single dissociation constant, showing that the two available sites on the dimer were equivalent and non-cooperative; values of the intrinsic dissociation constant varied from 2.5 X 10(-3) mol 1(-1) at pH 7.0 to 6 X 10(-3) at pH 6.5. Under intermediate conditions (pH 7.0, ionic strength=0.15 mol 1(-1)), where monomer and dimer coexisted, the binding of glucose showed weak positive cooperatively (Hill coefficient 1.2); in addition, the binding was dependent upon the concentration of enzyme in the direction of stronger binding at lower concentrations. The results show that the phenomenon of half-sites reactivity observed in the binding of glucose to crystalline hexokinase P-II does not occur in solution; the simplest explanation of our finding the two sites to be equivalent is that the dimer results from the homologous association of two identical subunits.

Vapour pressure of ammonium chloride aerosol: Effect of temperature and humidity

Science.gov (United States)

Pio, Casimiro A.; Harrison, Roy M.

The effect of relative humidity (RH) on the constant for dissociation of ammonium chloride into gaseous HCl and NH 3 has been estimated for different temperatures, using thermodynamic data. At RH over 75-85% the ammonium chloride aerosol exists in the liquid phase, with the dissociation constant two orders of magnitude lower at 98% RH than for solid aerosol at the same temperature. It is predicted that ammonium chloride aqueous aerosol forms predominantly in fogwater and cloud droplets, and in regions where local emissions of NH 3 are important.

Thermodynamic parameters associated with the binding of adrenaline and norephedrine to heparin

International Nuclear Information System (INIS)

Ali-Ali, A.K.; Buchanan, J.D.; Power, D.M.; Butler, J.

1983-01-01

Pulse radiolysis was used to determine the thermodynamic parameters (ΔG', ΔH' and ΔS') governing the binding of adrenalin and norephedrine to heparin. The complexes were completely dissociated by increasing concentrations of inorganic salts. Lower concentrations of divalent cations (e.g. Ca 2+ ) were more necessary to affect dissociation than those of monovalent cations (e.g. Na + ). For each interaction, an increase in drug binding occurred as the temperature was increased from ambient. However, a transition temperature was observed (48 degC) above which the drug was progressively released as temperature was increased. These observations probably reflect conformational changes induced in the heparin below and above its melting temperature. (author)

Thermodynamic parameters associated with the binding of adrenalin and norephedrine to heparin

International Nuclear Information System (INIS)

Al-Ali, A.K.; Buchanan, J.D.; Power, D.M.; Butler, J.

1983-01-01

Pulse radiolysis has been used to determine the thermodynamic parameters (ΔG', ΔH' and ΔS') governing the binding of adrenalin and norephedrine to heparin. These complexes were completely dissociated by increasing concentrations of inorganic salts. Lower concentrations of divalent cations (e.g. Ca 2+ ) than of monovalent cations (e.g. Na + ) were necessary to effect dissociation of the complex. For each interaction an increase in drug binding occurred as the temperature was increased from ambient. However, a transition temperature was observed (48 0 C) above which the drug was progressively released as the temperature was increased. These observations are discussed in terms of conformational changes induced in the polymer below and above its melting temperature. (author)

Promoting mechanism of N-doped single-walled carbon nanotubes for O2 dissociation and SO2 oxidation

Science.gov (United States)

Chen, Yanqiu; Yin, Shi; Chen, Yang; Cen, Wanglai; Li, Jianjun; Yin, Huaqiang

2018-03-01

Although heteroatom doping in carbon based catalysts have recently received intensive attentions, the role of the intrinsically porous structure of practical carbon materials and their potential synergy with doping atoms are still unclear. To investigate the complex effects, a range of N-doped single-walled carbon nanotubes (SWCNTs) were used to investigate their potential use for O2 dissociation and the subsequent SO2 oxidation using density functional theory. It is found that graphite N doping can synergize with the outer surface of SWCNTs to facilitate the dissociation of O2. The barrier for the dissociation on dual graphite N-doped SWCNT-(8, 8) is as low as 0.3 eV, and the subsequent SO2 oxidation is thermodynamically favorable and kinetically feasible. These results spotlight on developing promising carboncatalyst via utilization of porous gemometry and heteroatom-doping of carbon materials simultaneously.

Thermodynamics of ion-exchange on ferric antimonate

International Nuclear Information System (INIS)

Rawat, J.P.; Muktawat, K.P.S.

1981-01-01

A simple approach to ion-exchange equilibria on ferric antimonate has been applied. The values of selectivity coefficients for Ba 2+ , Mg 2+ , Ca 2+ and Sr 2+ have been measured using equilibrium experiments at constant ionic strength and at different temperatures from 20 to 60 0 C. The thermodynamic equilibrium constant and values of ΔG 0 , ΔH 0 and ΔS 0 are reported. (author)

Thermodynamic and transport properties of sodium liquid and vapor

International Nuclear Information System (INIS)

Fink, J.K.; Leibowitz, L.

1995-01-01

Data have been reviewed to obtain thermodynamically consistent equations for thermodynamic and transport properties of saturated sodium liquid and vapor. Recently published Russian recommendations and results of equation of state calculations on thermophysical properties of sodium have been included in this critical assessment. Thermodynamic properties of sodium liquid and vapor that have been assessed include: enthalpy, heat capacity at constant pressure, heat capacity at constant volume, vapor pressure, boiling point, enthalpy of vaporization, density, thermal expansion, adiabatic and isothermal compressibility, speed of sound, critical parameters, and surface tension. Transport properties of liquid sodium that have been assessed include: viscosity and thermal conductivity. For each property, recommended values and their uncertainties are graphed and tabulated as functions of temperature. Detailed discussions of the analyses and determinations of the recommended equations include comparisons with recommendations given in other assessments and explanations of consistency requirements. The rationale and methods used in determining the uncertainties in the recommended values are also discussed

Dissociative absorption: An empirically unique, clinically relevant, dissociative factor.

Science.gov (United States)

Soffer-Dudek, Nirit; Lassri, Dana; Soffer-Dudek, Nir; Shahar, Golan

2015-11-01

Research of dissociative absorption has raised two questions: (a) Is absorption a unique dissociative factor within a three-factor structure, or a part of one general dissociative factor? Even when three factors are found, the specificity of the absorption factor is questionable. (b) Is absorption implicated in psychopathology? Although commonly viewed as "non-clinical" dissociation, absorption was recently hypothesized to be specifically associated with obsessive-compulsive symptoms. To address these questions, we conducted exploratory and confirmatory factor analyses on 679 undergraduates. Analyses supported the three-factor model, and a "purified" absorption scale was extracted from the original inclusive absorption factor. The purified scale predicted several psychopathology scales. As hypothesized, absorption was a stronger predictor of obsessive-compulsive symptoms than of general psychopathology. In addition, absorption was the only dissociative scale that longitudinally predicted obsessive-compulsive symptoms. We conclude that absorption is a unique and clinically relevant dissociative tendency that is particularly meaningful to obsessive-compulsive symptoms. Copyright © 2015 Elsevier Inc. All rights reserved.

Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder.

Science.gov (United States)

Belli, Hasan; Ural, Cenk; Vardar, Melek Kanarya; Yesılyurt, Sema; Oncu, Fatıh

2012-10-01

The present study attempted to assess the dissociative symptoms and overall dissociative disorder comorbidity in patients with obsessive-compulsive disorder (OCD). In addition, we examined the relationship between the severity of obsessive-compulsive symptoms and dissociative symptoms. All patients admitted for the first time to the psychiatric outpatient unit were included in the study. Seventy-eight patients had been diagnosed as having OCD during the 2-year study period. Patients had to meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for OCD. Most (76.9%; n = 60) of the patients were female, and 23.1% (n = 18) of the patients were male. Dissociation Questionnaire was used to measure dissociative symptoms. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders interviews and Yale-Brown Obsessive Compulsive Checklist and Severity Scale were used. Eleven (14%) of the patients with OCD had comorbid dissociative disorder. The most prevalent disorder in our study was dissociative depersonalization disorder. Dissociative amnesia and dissociative identity disorder were common as well. The mean Yale-Brown score was 23.37 ± 7.27 points. Dissociation Questionnaire scores were between 0.40 and 3.87 points, and the mean was 2.23 ± 0.76 points. There was a statistically significant positive correlation between Yale-Brown points and Dissociation Questionnaire points. We conclude that dissociative symptoms among patients with OCD should alert clinicians for the presence of a chronic and complex dissociative disorder. Clinicians may overlook an underlying dissociative process in patients who have severe symptoms of OCD. However, a lack of adequate response to cognitive-behavioral and drug therapy may be a consequence of dissociative process. Copyright © 2012 Elsevier Inc. All rights reserved.

Misuse of thermodynamic entropy in economics

International Nuclear Information System (INIS)

Kovalev, Andrey V.

2016-01-01

The direct relationship between thermodynamic entropy and economic scarcity is only valid for a thermodynamically isolated economy. References to the second law of thermodynamics in economics within the context of scarcity ignore the fact that the earth is not an isolated system. The earth interacts with external sources and sinks of entropy and the resulting total entropy fluctuates around a constant. Even if the mankind finally proves unable to recycle industrial waste and close the technological cycle, the economic disruption caused by the depletion of natural resources may happen while the total thermodynamic entropy of the ecosystem remains essentially at the present level, because the transfer of chemically refined products may not increase significantly the total entropy, but it may decrease their recyclability. The inutility of industrial waste is not connected with its entropy, which may be exemplified with the case of alumina production. The case also demonstrates that industrially generated entropy is discharged into surroundings without being accumulated in ‘thermodynamically unavailable matter’. Material entropy, as a measure of complexity and economic dispersal of resources, can be a recyclability metric, but it is not a thermodynamic parameter, and its growth is not equivalent to the growth of thermodynamic entropy. - Highlights: • Entropy cannot be used as a measure of economic scarcity. • There is no anthropogenic entropy separate from the entropy produced naturally. • Inutility of industrial waste is not connected with its thermodynamic entropy. • Industrially generated entropy may or may not be accumulated in industrial waste. • Recyclability is more important than thermodynamic entropy of a product.

Determination of acidity constants and ionic mobilities of polyprotic peptide hormones by CZE

Czech Academy of Sciences Publication Activity Database

Šolínová, Veronika; Kašička, Václav

2013-01-01

Roč. 34, č. 18 (2013), s. 2655-2665 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : acid dissociation constant * gonadotropin-releasing hormones * ionization constant * peptides * pK(a) Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.161, year: 2013

Biochemical thermodynamics: applications of Mathematica.

Science.gov (United States)

Alberty, Robert A

2006-01-01

The most efficient way to store thermodynamic data on enzyme-catalyzed reactions is to use matrices of species properties. Since equilibrium in enzyme-catalyzed reactions is reached at specified pH values, the thermodynamics of the reactions is discussed in terms of transformed thermodynamic properties. These transformed thermodynamic properties are complicated functions of temperature, pH, and ionic strength that can be calculated from the matrices of species values. The most important of these transformed thermodynamic properties is the standard transformed Gibbs energy of formation of a reactant (sum of species). It is the most important because when this function of temperature, pH, and ionic strength is known, all the other standard transformed properties can be calculated by taking partial derivatives. The species database in this package contains data matrices for 199 reactants. For 94 of these reactants, standard enthalpies of formation of species are known, and so standard transformed Gibbs energies, standard transformed enthalpies, standard transformed entropies, and average numbers of hydrogen atoms can be calculated as functions of temperature, pH, and ionic strength. For reactions between these 94 reactants, the changes in these properties can be calculated over a range of temperatures, pHs, and ionic strengths, and so can apparent equilibrium constants. For the other 105 reactants, only standard transformed Gibbs energies of formation and average numbers of hydrogen atoms at 298.15 K can be calculated. The loading of this package provides functions of pH and ionic strength at 298.15 K for standard transformed Gibbs energies of formation and average numbers of hydrogen atoms for 199 reactants. It also provides functions of temperature, pH, and ionic strength for the standard transformed Gibbs energies of formation, standard transformed enthalpies of formation, standard transformed entropies of formation, and average numbers of hydrogen atoms for 94

THERMODYNAMICS AND ADSORPTION ISOTHERMS FOR THE ...

African Journals Online (AJOL)

BAFFA

data were tested using Freundlich and Langmuir adsorption isotherms. The values of the numeric constants ... Keywords: Adsorbate, Adsorbent, Adsorption isotherms, Maize cob, Thermodynamics. INTRODUCTION. Maize (Zea mays) ... several times with water, air – dried and ground to. 850μm particle size and finally kept ...

Correlation of thermodynamics and grain growth kinetics in nanocrystalline metals

International Nuclear Information System (INIS)

Song Xiaoyan; Zhang Jiuxing; Li Lingmei; Yang Keyong; Liu Guoquan

2006-01-01

We investigated the correlation of thermodynamics and grain growth kinetics of nanocrystalline metals both theoretically and experimentally. A model was developed to describe the thermodynamic properties of nanograin boundaries, which could give reliable predictions in the destabilization characteristics of nanograin structures and the slowing down of grain growth kinetics at a constant temperature. Both the temperature-varying and isothermal nanograin growth behaviors in pure nanocrystalline Co were studied to verify the thermodynamic predictions. The experimental results showing that discontinuous nanograin growth takes place at a certain temperature and grain growth rate decreases monotonically with time confirm our thermodynamics-based description of nanograin growth characteristics. Therefore, we propose a thermodynamic viewpoint to explain the deviation of grain growth kinetics in nanocrystalline metals from those of polycrystalline materials

Lagrangian formulation of irreversible thermodynamics and the second law of thermodynamics.

Science.gov (United States)

Glavatskiy, K S

2015-05-28

We show that the equations which describe irreversible evolution of a system can be derived from a variational principle. We suggest a Lagrangian, which depends on the properties of the normal and the so-called "mirror-image" system. The Lagrangian is symmetric in time and therefore compatible with microscopic reversibility. The evolution equations in the normal and mirror-imaged systems are decoupled and describe therefore independent irreversible evolution of each of the systems. The second law of thermodynamics follows from a symmetry of the Lagrangian. Entropy increase in the normal system is balanced by the entropy decrease in the mirror-image system, such that there exists an "integral of evolution" which is a constant. The derivation relies on the property of local equilibrium, which states that the local relations between the thermodynamic quantities in non-equilibrium are the same as in equilibrium.

Solvation numbers and hydration constant for thorium(IV) in ethanol-water medium

International Nuclear Information System (INIS)

Sedaira, H.; Idriss, K.A.; Hashem, E.Y.

1996-01-01

The solvation number and hydration constant of Th 4+ in ethanol-water medium were determined at 25 degrees C using UV-spectral and electrochemical measurements. A solvate formation equilibrium is demonstrated and characterized. Three molecules of ethanol (S) can bond to the metal cation with strengths comparable to that for H 2 O to form ThS 3 (H 2 O) 3 4+ . Formation of thorium monochelate with lawsone (2-hydroxy-1.4-naphthoquinone) eliminates bonding with alcohol molecules. The dissociation constant of the chelating agent s K a and the formation contant of the monochelated metal ion s K f * that are essentially independent of the solution composition are evaluated. Hydration titrations involving thorium-lawsone monochlate are performed and the data obtained from the changes of pH with solvent composition are analyzed. The solution independent constant, s K f * for thorium-lawsone complex formation in mixed aqueous ethanol is given by log x K f * =vpK a + log s K h - log [LH] - vpH + 3 log v where vpK a is the dissociation constant of the chelating agent LH in the solvent system of v volume fraction of water and s K h is the solution-independent hydration constant of thorium (IV) in the solvent system. Log-values for the constants s K h , s K f * and s K z * are found to be 7.8 ±0.02, 11.38±0.04 and -0.753, respectively

Cosmological constant is a conserved charge

Science.gov (United States)

Chernyavsky, Dmitry; Hajian, Kamal

2018-06-01

Cosmological constant can always be considered as the on-shell value of a top form in gravitational theories. The top form is the field strength of a gauge field, and the theory enjoys a gauge symmetry. We show that cosmological constant is the charge of the global part of the gauge symmetry, and is conserved irrespective of the dynamics of the metric and other fields. In addition, we introduce its conjugate chemical potential, and prove the generalized first law of thermodynamics which includes variation of cosmological constant as a conserved charge. We discuss how our new term in the first law is related to the volume–pressure term. In parallel with the seminal Wald entropy, this analysis suggests that pressure can also be considered as a conserved charge.

Mass-independent area (or entropy) and thermodynamic volume products in conformal gravity

Science.gov (United States)

Pradhan, Parthapratim

2017-06-01

In this work, we investigate the thermodynamic properties of conformal gravity in four dimensions. We compute the area (or entropy) functional relation for this black hole (BH). We consider both de Sitter (dS) and anti-de Sitter (AdS) cases. We derive the Cosmic-Censorship-Inequality which is an important relation in general relativity that relates the total mass of a spacetime to the area of all the BH horizons. Local thermodynamic stability is studied by computing the specific heat. The second-order phase transition occurs at a certain condition. Various types of second-order phase structure have been given for various values of a and the cosmological constant Λ in the Appendix. When a = 0, one obtains the result of Schwarzschild-dS and Schwarzschild-AdS cases. In the limit aM ≪ 1, one obtains the result of Grumiller spacetime, where a is nontrivial Rindler parameter or Rindler acceleration and M is the mass parameter. The thermodynamic volume functional relation is derived in the extended phase space, where the cosmological constant is treated as a thermodynamic pressure and its conjugate variable as a thermodynamic volume. The mass-independent area (or entropy) functional relation and thermodynamic volume functional relation that we have derived could turn out to be a universal quantity.

Dissociation in patients with dissociative seizures: relationships with trauma and seizure symptoms.

Science.gov (United States)

Pick, S; Mellers, J D C; Goldstein, L H

2017-05-01

This study aimed to extend the current understanding of dissociative symptoms experienced by patients with dissociative (psychogenic, non-epileptic) seizures (DS), including psychological and somatoform types of symptomatology. An additional aim was to assess possible relationships between dissociation, traumatic experiences, post-traumatic symptoms and seizure manifestations in this group. A total of 40 patients with DS were compared with a healthy control group (n = 43), matched on relevant demographic characteristics. Participants completed several self-report questionnaires, including the Multiscale Dissociation Inventory (MDI), Somatoform Dissociation Questionnaire-20, Traumatic Experiences Checklist and the Post-Traumatic Diagnostic Scale. Measures of seizure symptoms and current emotional distress (Hospital Anxiety and Depression Scale) were also administered. The clinical group reported significantly more psychological and somatoform dissociative symptoms, trauma, perceived impact of trauma, and post-traumatic symptoms than controls. Some dissociative symptoms (i.e. MDI disengagement, MDI depersonalization, MDI derealization, MDI memory disturbance, and somatoform dissociation scores) were elevated even after controlling for emotional distress; MDI depersonalization scores correlated positively with trauma scores while seizure symptoms correlated with MDI depersonalization, derealization and identity dissociation scores. Exploratory analyses indicated that somatoform dissociation specifically mediated the relationship between reported sexual abuse and DS diagnosis, along with depressive symptoms. A range of psychological and somatoform dissociative symptoms, traumatic experiences and post-traumatic symptoms are elevated in patients with DS relative to healthy controls, and seem related to seizure manifestations. Further studies are needed to explore peri-ictal dissociative experiences in more detail.

Predictions of hydrate plug dissociation with electrical heating

Energy Technology Data Exchange (ETDEWEB)

Davies, S.R.; Ivanic, J.; Sloan, E.D.

2005-07-01

The rate of dissociation for cylindrical hydrate plugs by the application of radial electrical heating was investigated for structure I and structure II hydrates for pressures of 7 MPa (1000 psia) and 14 MPa (2000 psia). Heating rates of 2.3 kWm{sup -3}, 4.5 kWm-3 and 6.8 kWm{sup -3} were investigated for a plug 91.4 cm (36 inches) in length and 2.54 cm (1 inch) in diameter. A heat transfer model was developed in cylindrical coordinates based on Fourier's Law with a boundary condition of constant heat flux at the pipe wall. The equation set was solved numerically using a finite difference grid and the standard explicit scheme. The model was found to replicate well the experimental observations with no fitted parameters. A computer program was formulated to allow the practicing engineer to simulate the dissociation of industrial hydrates with minimal complexity. This program was incorporated into the latest version of our CSMPlug program which has been used by a number of energy companies to predict hydrate plug dissociation rates in the field. (Author)

Some Simple Black Hole Thermodynamics

Science.gov (United States)

Lopresto, Michael C.

2003-05-01

In his recent popular book The Universe in a Nutshell, Steven Hawking gives expressions for the entropy1 and temperature (often referred to as the ``Hawking temperature''2 ) of a black hole:3 S = kc34ℏG A T = ℏc38πkGM, where A is the area of the event horizon, M is the mass, k is Boltzmann's constant, ℏ = h2π (h being Planck's constant), c is the speed of light, and G is the universal gravitational constant. These expressions can be used as starting points for some interesting approximations on the thermodynamics of a Schwarzschild black hole, of mass M, which by definition is nonrotating and spherical with an event horizon of radius R = 2GMc2.4,5

Non-equilibrium thermodynamics and energy distribution function of neutron gas in constant power reactor under coupling of neutrons and medium

International Nuclear Information System (INIS)

Hayasaka, Hideo

1983-01-01

The thermodynamics and the energy distribution function of the neutron gas in a constant power reactor are considered, taking into account the burn-up of fuel. To separate the secular motion of neutrons owing to fuel burn-up and the microscopic fluctuations of neutrons around this motion, a long time of the order of several months is divided into m equal intervals, and the respective states corresponding to m small time intervals are treated as quasi-stationary states. The local energy distribution function of the neutron gas in the quasi-stationary state is given by a generalized Boltzmann distribution specified by the respective generalized activity coefficient for each subsystem. The effects of fuel burn-up on the respective distribution functions for successive small time intervals are taken into account through various quantities relating to reactor physics, depending upon the fuel burn-up, by successive approximation. (author)

On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: I. Cosmic microwave background radiation

Science.gov (United States)

Fisenko, Anatoliy I.; Lemberg, Vladimir

2014-07-01

Using the explicit form of the functions to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies v 1≤ v≤ v 2 are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60-600 GHz frequency interval at the temperature T=2.72548 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant σ are calculated. In the case of the dipole spectrum, the constants a and σ, and the radiative and thermodynamic properties of the CMB radiation are obtained using the mean amplitude T amp=3.358 mK. It is shown that the Doppler shift leads to a renormalization of the radiation density constant a, the Stefan-Boltzmann constant σ, and the corresponding constants for the thermodynamic functions. The expressions for new astrophysical parameters, such as the entropy density/Boltzmann constant, and number density of CMB photons are obtained. The radiative and thermodynamic properties of the Cosmic Microwave Background radiation for the monopole and dipole spectra at redshift z≈1089 are calculated.

Simulating metabolism with statistical thermodynamics.

Science.gov (United States)

Cannon, William R

2014-01-01

New methods are needed for large scale modeling of metabolism that predict metabolite levels and characterize the thermodynamics of individual reactions and pathways. Current approaches use either kinetic simulations, which are difficult to extend to large networks of reactions because of the need for rate constants, or flux-based methods, which have a large number of feasible solutions because they are unconstrained by the law of mass action. This report presents an alternative modeling approach based on statistical thermodynamics. The principles of this approach are demonstrated using a simple set of coupled reactions, and then the system is characterized with respect to the changes in energy, entropy, free energy, and entropy production. Finally, the physical and biochemical insights that this approach can provide for metabolism are demonstrated by application to the tricarboxylic acid (TCA) cycle of Escherichia coli. The reaction and pathway thermodynamics are evaluated and predictions are made regarding changes in concentration of TCA cycle intermediates due to 10- and 100-fold changes in the ratio of NAD+:NADH concentrations. Finally, the assumptions and caveats regarding the use of statistical thermodynamics to model non-equilibrium reactions are discussed.

Thermodynamic and structural properties in complexing media

International Nuclear Information System (INIS)

Di Giandomenico, M.V.

2007-10-01

Protactinium is experiencing a renewal of interest in the frame of long-term energy production. Modelling the behaviour of this element in the geosphere requires thermodynamic and structural data relevant to environmental conditions. Now deep clayey formation are considered for the disposal of radioactive waste and high values of natural sulphate contents have been determined in pore water in equilibrium with clay surface. Because of its tendency to polymerisation, hydrolysis and sorption on all solid supports, the equilibria constants relative to monomer species were determined at tracer scale (ca. 10 - 12 M) with 233 Pa. The complexation constants of Pa(V) and sulphate ions were calculated starting from a systematic study of the apparent distribution coefficient D in the system TTA/Toluene/H 2 O/Na 2 SO 4 /HClO 4 /NaClO 4 and as a function of ionic strength, temperature, free sulphate, protons and chelatant concentration. First of all, the interaction between free species H + , SO 4 - , Na + leads to the formation of HSO 4 - and NaSO 4 - , for which concentrations depend upon the related thermodynamic constants. For this purpose a computer code was developed in order to determine all free species concentration. This iterative code takes into account the influence of temperature and ionic strength (SIT modelling) on thermodynamic constants. The direct measure of Pa(V) in the organic and aqueous phase by g-spectrometry had conducted to estimate the apparent distribution coefficient D as function of free sulphate ions. Complexation constants have been determined after a mathematical treatment of D. The extrapolation of these constants at zero ionic strength have been realized by SIT modelling at different temperatures. Besides, enthalpy and entropy values were calculated. Parallelly, the structural study of Pa(V) was performed using 231 Pa. XANES and EXAFS spectra show unambiguously the absence of the trans di-oxo bond that characterizes the other early actinide

The 4th Thermodynamic Principle?

International Nuclear Information System (INIS)

Montero Garcia, Jose de la Luz; Novoa Blanco, Jesus Francisco

2007-01-01

It should be emphasized that the 4th Principle above formulated is a thermodynamic principle and, at the same time, is mechanical-quantum and relativist, as it should inevitably be and its absence has been one of main the theoretical limitations of the physical theory until today.We show that the theoretical discovery of Dimensional Primitive Octet of Matter, the 4th Thermodynamic Principle, the Quantum Hexet of Matter, the Global Hexagonal Subsystem of Fundamental Constants of Energy and the Measurement or Connected Global Scale or Universal Existential Interval of the Matter is that it is possible to be arrived at a global formulation of the four 'forces' or fundamental interactions of nature. The Einstein's golden dream is possible

Thermodynamic volume and the extended Smarr relation

Energy Technology Data Exchange (ETDEWEB)

Hyun, Seungjoon; Jeong, Jaehoon; Park, Sang-A; Yi, Sang-Heon [Department of Physics, College of Science, Yonsei University,Seoul 120-749 (Korea, Republic of)

2017-04-10

We continue to explore the scaling transformation in the reduced action formalism of gravity models. As an extension of our construction, we consider the extended forms of the Smarr relation for various black holes, adopting the cosmological constant as the bulk pressure as in some literatures on black holes. Firstly, by using the quasi-local formalism for charges, we show that, in a general theory of gravity, the volume in the black hole thermodynamics could be defined as the thermodynamic conjugate variable to the bulk pressure in such a way that the first law can be extended consistently. This, so called, thermodynamic volume can be expressed explicitly in terms of the metric and field variables. Then, by using the scaling transformation allowed in the reduced action formulation, we obtain the extended Smarr relation involving the bulk pressure and the thermodynamic volume. In our approach, we do not resort to Euler’s homogeneous scaling of charges while incorporating the would-be hairy contribution without any difficulty.

Cosmological constant--the weight of the vacuum

International Nuclear Information System (INIS)

Padmanabhan, T.

2003-01-01

Recent cosmological observations suggest the existence of a positive cosmological constant Λ with the magnitude Λ(Gℎ/c 3 )∼10 -123 . This review discusses several aspects of the cosmological constant both from the cosmological (Sections 1-6) and field theoretical (Sections 7-11) perspectives. After a brief introduction to the key issues related to cosmological constant and a historical overview, a summary of the kinematics and dynamics of the standard Friedmann model of the universe is provided. The observational evidence for cosmological constant, especially from the supernova results, and the constraints from the age of the universe, structure formation, Cosmic Microwave Background Radiation (CMBR) anisotropies and a few others are described in detail, followed by a discussion of the theoretical models (quintessence, tachyonic scalar field, ...) from different perspectives. The latter part of the review (Sections 7-11) concentrates on more conceptual and fundamental aspects of the cosmological constant like some alternative interpretations of the cosmological constant, relaxation mechanisms to reduce the cosmological constant to the currently observed value, the geometrical structure of the de Sitter spacetime, thermodynamics of the de Sitter universe and the role of string theory in the cosmological constant problem

Thermodynamics of Horndeski black holes with non-minimal derivative coupling

Energy Technology Data Exchange (ETDEWEB)

Miao, Yan-Gang [Nankai University, School of Physics, Tianjin (China); Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Potsdam (Germany); Xu, Zhen-Ming [Nankai University, School of Physics, Tianjin (China)

2016-11-15

We explore thermodynamic properties of a new class of Horndeski black holes whose action contains a non-minimal kinetic coupling of a massless real scalar and the Einstein tensor. Our treatment is based on the well-accepted consideration, where the cosmological constant is dealt with as thermodynamic pressure and the mass of black holes as thermodynamic enthalpy. We resort to a newly introduced intensive thermodynamic variable, i.e., the coupling strength of the scalar and tensor whose dimension is length square, and thus yield both the generalized first law of thermodynamics and the generalized Smarr relation. Our result indicates that this class of Horndeski black holes presents rich thermodynamic behaviors and critical phenomena. Especially in the case of the presence of an electric field, these black holes undergo two phase transitions. Once the charge parameter exceeds its critical value, or the cosmological parameter does not exceed its critical value, no phase transitions happen and the black holes are stable. As a by-product, we point out, the coupling strength acts as the thermodynamic pressure in thermodynamics. (orig.)

Thermodynamics of Horndeski black holes with non-minimal derivative coupling

International Nuclear Information System (INIS)

Miao, Yan-Gang; Xu, Zhen-Ming

2016-01-01

We explore thermodynamic properties of a new class of Horndeski black holes whose action contains a non-minimal kinetic coupling of a massless real scalar and the Einstein tensor. Our treatment is based on the well-accepted consideration, where the cosmological constant is dealt with as thermodynamic pressure and the mass of black holes as thermodynamic enthalpy. We resort to a newly introduced intensive thermodynamic variable, i.e., the coupling strength of the scalar and tensor whose dimension is length square, and thus yield both the generalized first law of thermodynamics and the generalized Smarr relation. Our result indicates that this class of Horndeski black holes presents rich thermodynamic behaviors and critical phenomena. Especially in the case of the presence of an electric field, these black holes undergo two phase transitions. Once the charge parameter exceeds its critical value, or the cosmological parameter does not exceed its critical value, no phase transitions happen and the black holes are stable. As a by-product, we point out, the coupling strength acts as the thermodynamic pressure in thermodynamics. (orig.)

Thermodynamically consistent model calibration in chemical kinetics

Directory of Open Access Journals (Sweden)

Goutsias John

2011-05-01

Full Text Available Abstract Background The dynamics of biochemical reaction systems are constrained by the fundamental laws of thermodynamics, which impose well-defined relationships among the reaction rate constants characterizing these systems. Constructing biochemical reaction systems from experimental observations often leads to parameter values that do not satisfy the necessary thermodynamic constraints. This can result in models that are not physically realizable and may lead to inaccurate, or even erroneous, descriptions of cellular function. Results We introduce a thermodynamically consistent model calibration (TCMC method that can be effectively used to provide thermodynamically feasible values for the parameters of an open biochemical reaction system. The proposed method formulates the model calibration problem as a constrained optimization problem that takes thermodynamic constraints (and, if desired, additional non-thermodynamic constraints into account. By calculating thermodynamically feasible values for the kinetic parameters of a well-known model of the EGF/ERK signaling cascade, we demonstrate the qualitative and quantitative significance of imposing thermodynamic constraints on these parameters and the effectiveness of our method for accomplishing this important task. MATLAB software, using the Systems Biology Toolbox 2.1, can be accessed from http://www.cis.jhu.edu/~goutsias/CSS lab/software.html. An SBML file containing the thermodynamically feasible EGF/ERK signaling cascade model can be found in the BioModels database. Conclusions TCMC is a simple and flexible method for obtaining physically plausible values for the kinetic parameters of open biochemical reaction systems. It can be effectively used to recalculate a thermodynamically consistent set of parameter values for existing thermodynamically infeasible biochemical reaction models of cellular function as well as to estimate thermodynamically feasible values for the parameters of new

Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

Science.gov (United States)

Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

2015-02-01

The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation-deprotonation behavior was determined by continuous acid-base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m2/g and large numbers of surface hydroxyl functional groups (i.e. tbnd Si-OH, tbnd Fe-OH, and tbnd Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K1, log K2) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation-deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

The Theory of Thermodynamics for Chemical Reactions in Dispersed Heterogeneous Systems

Science.gov (United States)

Yongqiang; Baojiao; Jianfeng

1997-07-01

In this paper, the expressions of Gibbs energy change, enthalpy change, entropy change, and equilibrium constant for chemical reactions in dispersed heterogeneous systems are derived using classical thermodynamics theory. The thermodynamical relations for the same reaction system between the dispersed and the block state are also derived. The effects of degree of dispersion on thermodynamical properties, reaction directions, and chemical equilibria are discussed. The results show that the present equation of thermodynamics for chemical reactions is only a special case of the above-mentioned formulas and that the effect of the dispersity of a heterogeneous system on the chemical reaction obeys the Le Chatelier principle of movement of equilibria.

Development of a collision induced dissociation ion cyclotron resonance spectrometer

International Nuclear Information System (INIS)

Fan, Y.N.

1982-01-01

A transient analysis ion cyclotron resonance spectrometer is developed to investigate the phenomena of collision induced dissociation. The Fourier transform method and the modified maximum entropy spectral analysis or covariance least square method are implemented in measuring the mass spectrum of the ion ensemble. The Fourier transform method can be used in quantitative analysis while the maximum entropy method as developed here is useful for qualitative analysis only. The cyclotron resonance frequency, relaxation time constant, and the relative ion population are observable from the Fourier transform spectrum. These parameters are very important in investigating collision induced dissociation process and other topics in gas phase chemistry. The ion cyclotron resonance spectrometer is not only developed to study fragments and their abundance from a parent ion, but also to determine the threshold energy and reaction cross section in the collision induced dissociation process. When hard sphere model is used in the ion-molecule collision, the radius of acetone ion measured from the reactive cross section is 2.2 angstrom which is very close to the physical dimension of acetone. The threshold energy for acetone ion in collision induced dissociation process is 1.8 eV which is similar to the result obtained by the angle-resolved mass spectrometer

The influence of temperature and P/P0 upon cationic exchange constants

International Nuclear Information System (INIS)

Blanc, P.; Vieillard, P.; Gailhanou, H.; Gaboreau, S.; Gaucher, E.C.; Giffaut, E.

2010-01-01

Document available in extended abstract form only. The knowledge of thermodynamic properties of clay minerals forming clay materials is important in the context of a disposal within clayey formations (Callovo-Oxfordian argillite) or for clayey barriers. Different experiments have been previously performed concerning the long term behavior of clay materials, indicating that strong transformations are influenced by the alkaline solutions issued from the cementitious materials. But the first stages of the transformations affect the hydration and exchange capacity of the mineral, which are closely related to their retention properties. This work aims at assessing the influence of temperature and relative humidity upon the thermodynamic functions related to cationic exchange and hydration reactions. It is carried out within the framework of the Thermochimie project, aiming at defining a consistent thermodynamic database for modeling purposes. This work is an extension of the thermodynamic of hydration study carried out by Vieillard et al. (2010). Using the same, regular, solid solution model developed by the authors, we first consider the influence of temperature on the hydration reaction by expressing the hydration constant LogK hyd (T) according to the enthalpy and entropy of hydration and to the gas constant. Predicted isotherms are then compared with experimental data acquired on the MX80 smectite at 40, 60, 75, 90 and 100 deg. C. We now consider a cationic exchange reaction between cations A+ and B+, with z cations per mole of smectite and y2 and y1 mole of water per mole of smectite for A and B end members, respectively. The exchange constant LogK A/B , for a given temperature and relative humidity, is expressed as a function of the difference between anhydrous end members, and of the difference between anhydrous end-members activities. A comparison with room temperature exchange constants derived from experiments suggests that discrepancies are related to

Kinetics of reaction dimer fatty acid C_36 with 1,9 diamino nonane and determination of thermodynamic constants by use of thermogravimetric analysis tga, and rheological constants for the resulted polyamide

International Nuclear Information System (INIS)

Mohammad, H.; Falah, Al; Hammoy, M.

2014-01-01

Study the kinetics degradation of poly (dimeric acid C_36 with 1.9 – diamino nonane) was carried out by thermal analysis (TGA), and thermodynamic and equilibrium constants have been defined, moreover, study the kinetics of reaction between 1.9 – diamino nonane and dimer fatty acid C_36 was carried out in molten state, the reaction was performed at 160°, the acid value, and percentage of carboxylic functions of the product were determined. The polyamidation reaction was found to be of overall second order until conversion of 97% at 160°, then the order of reaction changes. The degree of dispersion, number molecular weight, weight molecular weight ,and viscosity molecular weight have been calculated during different times.The relationships between degree of dispersion, number Average molecular weight, weight average molecular weight, and viscosity molecular weight with time is linear at160°. Spectroscopy studies were carried out by infra-red and ultraviolet spectroscopy (author).

Thermal dissociation of molten KHSO4: Temperature dependence of Raman spectra and thermodynamics

DEFF Research Database (Denmark)

Knudsen, Christian B.; Kalampounias, Angelos G.; Fehrmann, Rasmus

2008-01-01

Raman spectroscopy is used to study the thermal dissociation of molten KHSO4 at temperatures of 240-450 degrees C under static equilibrium conditions. Raman spectra obtained at 10 different temperatures for the molten phase and for the vapors thereof exhibit vibrational wavenumbers and relative...... process taking place to a significant extent in the temperature range of the investigation and for determining its enthalpy to be Delta H degrees = 64.9 +/- 2.9 kJ mol(-1). The importance of these findings for the understanding of the performance of the industrially important sulfuric acid catalyst. under...

Dissociation in mediation

Directory of Open Access Journals (Sweden)

Daniela Muraru

2008-01-01

Full Text Available This paper approaches several texts that are part of the so-called discourse of mediation, adopting a pragma-dialectical perspective of the theory of dissociation. It is an attempt to identify the uses of dissociative patterns, with special emphasis on the indicators of dissociation. The paper investigates the various uses of the concept of dissociation as a discursive technique in the argumentation on the different aspects that are involved in international conflict, such as the discussion of the notion of peace. The purpose is to identify the role of dissociation, as a device strategically used by the mediator to help the parties minimize the disagreement space, and come to a conflict resolution.

Isotope and Electric Field Effects in Dissociative Recombination of D3+

International Nuclear Information System (INIS)

Larsson, M.; Rosen, S.; Danared, H.; Larson, A.; Le Padellec, A.; Semaniak, J.; Stroemholm, C.; Peterson, J.R.

1997-01-01

The cross section for dissociative recombination of vibrationally cold D 3 + has been measured at the ion storage ring CRYRING. The rate constant at 300K, α=2.7x10 -8 cm 3 s -1 , is a factor of 4.3 smaller than the corresponding value for H 3 + measured earlier in CRYRING. An electric field of 30V/cm was introduced in the electron-ion interaction region. This had no measurable effect on the dissociative recombination cross section. This suggests that the cross sections measured in storage rings for H 3 + and its isotopic variants can be directly compared with theoretical results once such results become available. copyright 1997 The American Physical Society

Bringing metabolic networks to life: convenience rate law and thermodynamic constraints

Directory of Open Access Journals (Sweden)

Klipp Edda

2006-12-01

Full Text Available Abstract Background Translating a known metabolic network into a dynamic model requires rate laws for all chemical reactions. The mathematical expressions depend on the underlying enzymatic mechanism; they can become quite involved and may contain a large number of parameters. Rate laws and enzyme parameters are still unknown for most enzymes. Results We introduce a simple and general rate law called "convenience kinetics". It can be derived from a simple random-order enzyme mechanism. Thermodynamic laws can impose dependencies on the kinetic parameters. Hence, to facilitate model fitting and parameter optimisation for large networks, we introduce thermodynamically independent system parameters: their values can be varied independently, without violating thermodynamical constraints. We achieve this by expressing the equilibrium constants either by Gibbs free energies of formation or by a set of independent equilibrium constants. The remaining system parameters are mean turnover rates, generalised Michaelis-Menten constants, and constants for inhibition and activation. All parameters correspond to molecular energies, for instance, binding energies between reactants and enzyme. Conclusion Convenience kinetics can be used to translate a biochemical network – manually or automatically - into a dynamical model with plausible biological properties. It implements enzyme saturation and regulation by activators and inhibitors, covers all possible reaction stoichiometries, and can be specified by a small number of parameters. Its mathematical form makes it especially suitable for parameter estimation and optimisation. Parameter estimates can be easily computed from a least-squares fit to Michaelis-Menten values, turnover rates, equilibrium constants, and other quantities that are routinely measured in enzyme assays and stored in kinetic databases.

Determination of stability constants of aminoglycoside antibiotics with their metal complexes

Science.gov (United States)

Tiwow, Vanny M. A.

2014-03-01

One group of aminoglycoside antibiotics contains aminosugars. The aminosugar neomycin B with its derivate product neamine (2-Deoxy-4-0-(2,6-diamino-2,6-dideoxy-α-D-glucopyranosyl)-D-Streptamine) was identified as a free ligands and metal complexes. In particular, the stability constants of metal complexes by potentiometric titration techniques were investigated. Our previous study had determined the acid dissociation constants of these aminosugars with few metal complexes in fair depth. In this work, the complexation of two pyridine-containing amino alcohols and an amino sugar (neamine) have been measured potentiometrically. For instance, the stability constant of copper(II) complexation were determine and the model system generated an excellent fit. Stability constants with several metals have been determined and will be reported.

Universal relation for size dependent thermodynamic properties of metallic nanoparticles.

Science.gov (United States)

Xiong, Shiyun; Qi, Weihong; Cheng, Yajuan; Huang, Baiyun; Wang, Mingpu; Li, Yejun

2011-06-14

The previous model on surface free energy has been extended to calculate size dependent thermodynamic properties (i.e., melting temperature, melting enthalpy, melting entropy, evaporation temperature, Curie temperature, Debye temperature and specific heat capacity) of nanoparticles. According to the quantitative calculation of size effects on the calculated thermodynamic properties, it is found that most thermodynamic properties of nanoparticles vary linearly with 1/D as a first approximation. In other words, the size dependent thermodynamic properties P(n) have the form of P(n) = P(b)(1 -K/D), in which P(b) is the corresponding bulk value and K is the material constant. This may be regarded as a scaling law for most of the size dependent thermodynamic properties for different materials. The present predictions are consistent literature values. This journal is © the Owner Societies 2011

Synthesis, Acidity Constants and Tautomeric Structure of the Diazonium Coupling Products of 2-(Benzylsulfanyl)-7H-purin-6-one in Its Ground and Excited States

OpenAIRE

Darwish, Elham S.; Mosselhi, Mosselhi A.; Altalbawy, Farag M.; Saad, Hosam A.

2011-01-01

A series of new 8-arylhydrazono-2-(benzylsulfanyl)-7H-purin-6-ones 6 were synthesized, their electronic absorption spectra in different organic solvents of varying polarities were investigated and their acid dissociation constants in both the ground and excited states were determined spectrophotometrically. The tautomeric structures of such products were elucidated by spectral analyses and correlation of their acid dissociation constants with the Hammett equation. The results indicated that t...

Thermodynamical description of stationary, asymptotically flat solutions with conical singularities

International Nuclear Information System (INIS)

Herdeiro, Carlos; Rebelo, Carmen; Radu, Eugen

2010-01-01

We examine the thermodynamical properties of a number of asymptotically flat, stationary (but not static) solutions having conical singularities, with both connected and nonconnected event horizons, using the thermodynamical description recently proposed in [C. Herdeiro, B. Kleihaus, J. Kunz, and E. Radu, Phys. Rev. D 81, 064013 (2010).]. The examples considered are the double-Kerr solution, the black ring rotating in either S 2 or S 1 , and the black Saturn, where the balance condition is not imposed for the latter two solutions. We show that not only the Bekenstein-Hawking area law is recovered from the thermodynamical description, but also the thermodynamical angular momentum is the Arnowitt-Deser-Misner angular momentum. We also analyze the thermodynamical stability and show that, for all these solutions, either the isothermal moment of inertia or the specific heat at constant angular momentum is negative, at any point in parameter space. Therefore, all these solutions are thermodynamically unstable in the grand canonical ensemble.

Thermodynamic properties of titanates, zirconates and hafnates of alkaline earth metals

Energy Technology Data Exchange (ETDEWEB)

1978-02-01

The problems are considered arising in critical analysis and choosing recommended values of thermodynamic constants of the series of the most important perovskites-ferroelectrics-titanates, zirconates, and hafnates of alkaline-earth metals finding application in modern radioelectronics. Recommended values of standard thermodynamic values are given: heat capacity Csub(p,298) , enthalpy change H/sub 298/-H/sub 0/, entropy S/sub 298/, heat formation ..delta..Hsub(f,298 ), free energy formation ..delta..Gsub(f,298) , temperatures and heats of phase transitions with indication of errors for the adopted values. The effect of impurities on thermal constants of phase transitions is discussed. The relationships between thermodynamic characteristics of perovskites and crystal structure as well as the effect of orthorhombic distortions of ideal perovskite lattice on entropy of the compounds have been considered. Along with thermodynamic methods of investigation, a great attention is given to other physical methods which have been used for finding temperature regions of phase transitions, Curie points, and temperatures of transition from ferroelectric to paraelectric state. The importance of physical methods is emphasized in those cases when phase transitions are accompanied by small energy changes and are not fixed in measuring heat capacity.

Thermodynamics of gravitationally induced particle creation scenario in DGP braneworld

Energy Technology Data Exchange (ETDEWEB)

Jawad, Abdul; Rani, Shamaila; Rafique, Salman [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan)

2018-01-15

In this paper, we discuss the thermodynamical analysis for gravitationally induced particle creation scenario in the framework of DGP braneworld model. For this purpose, we consider apparent horizon as the boundary of the universe. We take three types of entropy such as Bakenstein entropy, logarithmic corrected entropy and power law corrected entropy with ordinary creation rate Γ. We analyze the first law and generalized second law of thermodynamics analytically for these entropies which hold under some constraints. The behavior of total entropy in each case is also discussed which implies the validity of generalized second law of thermodynamics. Also, we check the thermodynamical equilibrium condition for two phases of creation rate, that is constant and variable Γ and found its vitality in all cases of entropy. (orig.)

Thermodynamics of gravitationally induced particle creation scenario in DGP braneworld

International Nuclear Information System (INIS)

Jawad, Abdul; Rani, Shamaila; Rafique, Salman

2018-01-01

In this paper, we discuss the thermodynamical analysis for gravitationally induced particle creation scenario in the framework of DGP braneworld model. For this purpose, we consider apparent horizon as the boundary of the universe. We take three types of entropy such as Bakenstein entropy, logarithmic corrected entropy and power law corrected entropy with ordinary creation rate Γ. We analyze the first law and generalized second law of thermodynamics analytically for these entropies which hold under some constraints. The behavior of total entropy in each case is also discussed which implies the validity of generalized second law of thermodynamics. Also, we check the thermodynamical equilibrium condition for two phases of creation rate, that is constant and variable Γ and found its vitality in all cases of entropy. (orig.)

Shock-Tube Measurement of Acetone Dissociation Using Cavity-Enhanced Absorption Spectroscopy of CO.

Science.gov (United States)

Wang, Shengkai; Sun, Kai; Davidson, David F; Jeffries, Jay B; Hanson, Ronald K

2015-07-16

A direct measurement for the rate constant of the acetone dissociation reaction (CH3COCH3 = CH3CO + CH3) was conducted behind reflected shock wave, utilizing a sub-ppm sensitivity CO diagnostic achieved by cavity-enhanced absorption spectroscopy (CEAS). The current experiment eliminated the influence from secondary reactions and temperature change by investigating the clean pyrolysis of <20 ppm acetone in argon. For the first time, the acetone dissociation rate constant (k1) was directly measured over 5.5 orders of magnitude with a high degree of accuracy: k1 (1004-1494 K, 1.6 atm) = 4.39 × 10(55) T(-11.394) exp(-52 140K/T) ± 24% s(-1). This result was seen to agree with most previous studies and has bridged the gap between their temperature and pressure conditions. The current work also served as an example demonstration of the potential of using the CEAS technique in shock-tube kinetics studies.

Thermodynamic properties of open noncritical string in external electromagnetic field

International Nuclear Information System (INIS)

Lichtzier, I.M.; Odintsov, S.D.; Bytsenko, A.A.

1991-01-01

We investigate the thermodynamics of open noncritical string (charged and neutral) in an external constant magnetic field. The free energy and Hagedorn temperature are calculated. It is shown that Hagedorn temperature is the same as in the absence of constant magnetic field. We present also the expressions for the free energy and Hagedorn temperature of the neutral open noncritical string in an external constant electromagnetic field. In this case Hagedorn temperature depends on the external electric field. (author)

Low-temperature behaviour of an ideal Bose gas and some forbidden thermodynamic cycles

International Nuclear Information System (INIS)

Chen Jincan; Lin Bihong

2003-01-01

Based on the equation of state of an ideal Bose gas, the heat capacities at constant volume and constant pressure of the Bose system are derived and used to analyse the low-temperature behaviour of the Bose system. It is expounded that some important thermodynamic processes such as a constant pressure and an adiabatic process cannot be carried out from the region of T > T c to that of T c , where T c is the critical temperature of Bose-Einstein condensation of the Bose system. Consequently, some typical thermodynamic cycles such as the Carnot cycle, Brayton cycle, Otto cycle, Ericsson cycle, Diesel cycle and Atkinson cycle cannot be operated across the critical temperature T c of Bose-Einstein condensation of an ideal Bose gas

Thermodynamics of Micellar Systems : Comparison of Mass Action and Phase Equilibrium Models for the Calculation of Standard Gibbs Energies of Micelle Formation

NARCIS (Netherlands)

Blandamer, Michael J.; Cullis, Paul M.; Soldi, L. Giorgio; Engberts, Jan B.F.N.; Kacperska, Anna; Os, Nico M. van

1995-01-01

Micellar colloids are distinguished from other colloids by their association-dissociation equilibrium in solution between monomers, counter-ions and micelles. According to classical thermodynamics, the standard Gibbs energy of formation of micelles at fixed temperature and pressure can be related to

The co-occurrence of PTSD and dissociation: differentiating severe PTSD from dissociative-PTSD.

Science.gov (United States)

Armour, Cherie; Karstoft, Karen-Inge; Richardson, J Don

2014-08-01

A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD. The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD. The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity scores were created reflecting the sum of the frequency and intensity items from each of the 17 PTSD and 3 dissociation items. The CAPS severity scores were used as indicators in a latent profile analysis (LPA) to investigate the existence of a dissociative-PTSD subtype. Subsequently, several covariates were added to the model to explore differences between severe PTSD alone and dissociative-PTSD. The LPA identified five classes: one of which constituted a severe PTSD group (30.5 %), and one of which constituted a dissociative-PTSD group (13.7 %). None of the included, demographic, trauma, or clinical covariates were significantly predictive of membership in the dissociative-PTSD group compared to the severe PTSD group. In conclusion, a significant proportion of individuals report high levels of dissociation alongside their PTSD, which constitutes a dissociative-PTSD subtype. Further investigation is needed to identify which factors may increase or decrease the likelihood of membership in a dissociative-PTSD subtype group compared to a severe PTSD only group.

Irreversible Thermodynamics of the Universe: Constraints from Planck Data

International Nuclear Information System (INIS)

Saha, Subhajit; Chakraborty, Subenoy; Biswas, Atreyee

2014-01-01

The present work deals with irreversible universal thermodynamics. The homogenous and isotropic flat model of the universe is chosen as open thermodynamical system and nonequilibrium thermodynamics comes into picture. For simplicity, entropy flow is considered only due to heat conduction. Further, due to Maxwell-Cattaneo modified Fourier law for nonequilibrium phenomenon, the temperature satisfies damped wave equation instead of heat conduction equation. Validity of generalized second law of thermodynamics (GSLT) has been investigated for universe bounded by apparent or event horizon with cosmic substratum as perfect fluid with constant or variable equation of state or interacting dark species. Finally, we have used three Planck data sets to constrain the thermal conductivity λ and the coupling parameter b 2 . These constraints must be satisfied in order for GSLT to hold for universe bounded by apparent or event horizons

A thermodynamic study of La(III)L-alanine complexes

International Nuclear Information System (INIS)

Elzawawy, F.M.

1991-01-01

The protonation constants of L-alanine and the complex formation constants of its La(III) complexes were determined by potentiometric studies at ionic strengths 0.06, 0.1, and 0.15 mol dm -3 (NaClO 4 ) and at different temperatures 20, 27, and 35 O C. The data together with the derived thermodynamic parameters ΔH O , ΔS O , and ΔG O are reported and discussed. (author)

Pressure and volume in the first law of black hole thermodynamics

Science.gov (United States)

Dolan, Brian P.

2011-12-01

The mass of a black hole is interpreted, in terms of thermodynamic potentials, as being the enthalpy, with the pressure given by the cosmological constant. The volume is then defined as being the Legendre transform of the pressure, and the resulting relation between volume and pressure is explored in the case of positive pressure. A virial expansion is developed and a van der Waals like critical point determined. The first law of black hole thermodynamics includes a PdV term which modifies the maximal efficiency of a Penrose process. It is shown that, in four-dimensional spacetime with a negative cosmological constant, an extremal charged rotating black hole can have an efficiency of up to 75%, while for an electrically neutral rotating black hole this figure is reduced to 52%, compared to the corresponding values of 50% and 29% respectively when the cosmological constant is zero.

Pressure and volume in the first law of black hole thermodynamics

International Nuclear Information System (INIS)

Dolan, Brian P

2011-01-01

The mass of a black hole is interpreted, in terms of thermodynamic potentials, as being the enthalpy, with the pressure given by the cosmological constant. The volume is then defined as being the Legendre transform of the pressure, and the resulting relation between volume and pressure is explored in the case of positive pressure. A virial expansion is developed and a van der Waals like critical point determined. The first law of black hole thermodynamics includes a PdV term which modifies the maximal efficiency of a Penrose process. It is shown that, in four-dimensional spacetime with a negative cosmological constant, an extremal charged rotating black hole can have an efficiency of up to 75%, while for an electrically neutral rotating black hole this figure is reduced to 52%, compared to the corresponding values of 50% and 29% respectively when the cosmological constant is zero. (paper)

The adsorption and dissociation of water molecule on goethite (010) surface: A DFT approach

Energy Technology Data Exchange (ETDEWEB)

Zhou, Long, E-mail: shuweixia@ouc.edu.cn [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China); Xiu, Fangyuan [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China); Qiu, Meng [Qingdao Institute of Bioenergy and Bioprocess Technology (China); Xia, Shuwei; Yu, Liangmin [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China)

2017-01-15

Graphical abstract: The optimized structure of hydrated goethite (010) surface with medium water coverage (water density about 6.7 H{sub 2}O/nm{sup 2}). - Highlights: • Stable adsorption and dissociation structure of H{sub 2}O on goethite (010) surface was investigated by DFT. • Reasonable path for water dissociation was proposed by transitional state analysis. • The mechanism of water adsorption on goethite and binding nature were revealed by PDOS. - Abstract: Using density functional theory (DFT) calculation, we investigate the configuration, stability and electronic properties of fresh cleaved (010) goethite surface (Pnma) and this surface exposed to water monolayer at low, medium and high coverage. Water is predicted to be chemisorbed to the surface, together with the surface reconstruction. The interaction energy of the most stable configuration of both low and medium coverage per water molecule is almost the same (−1.17 eV), while that of high coverage is much lower (less than 1.03 eV). It indicates that highly hydrated surface is less stable. PDOS analysis reveals the adsorption of H{sub 2}O is due to the formation of Fe−O bond, caused by overlapping of Fe's 3d and O's 2p orbitals. Dissociation processes at low and medium water coverage are non-spontaneous; while at high coverage, it can undertake spontaneously both thermodynamically and dynamically. The dissociation paths of all three water coverage are the similar. The proton from one adsorbed water is likely to dissociate to bind to the vicinal surface μ{sub 3}−O as an intermediate product; the proton belonged to μ{sub 3}−O transferred to the neighbor surface μ{sub 2}−O as the dissociative configuration.

Multiphoton dissociation and thermal unimolecular reactions induced by infrared lasers

International Nuclear Information System (INIS)

Dai, H.L.

1981-04-01

Multiphoton dissociation (MPD) of ethyl chloride was studied using a tunable 3.3 μm laser to excite CH stretches. The absorbed energy increases almost linearly with fluence, while for 10 μm excitation there is substantial saturation. Much higher dissociation yields were observed for 3.3 μm excitation than for 10 μm excitation, reflecting bottlenecking in the discrete region of 10 μm excitation. The resonant nature of the excitation allows the rate equations description for transitions in the quasicontinuum and continuum to be extended to the discrete levels. Absorption cross sections are estimated from ordinary ir spectra. A set of cross sections which is constant or slowly decreasing with increasing vibrational excitation gives good fits to both absorption and dissociation yield data. The rate equations model was also used to quantitatively calculate the pressure dependence of the MPD yield of SF 6 caused by vibrational self-quenching. Between 1000-3000 cm -1 of energy is removed from SF 6 excited to approx. > 60 kcal/mole by collision with a cold SF 6 molecule at gas kinetic rate. Calculation showed the fluence dependence of dissociation varies strongly with the gas pressure. Infrared multiphoton excitation was applied to study thermal unimolecular reactions. With SiF 4 as absorbing gas for the CO 2 laser pulse, transient high temperature pulses were generated in a gas mixture. IR fluorescence from the medium reflected the decay of the temperature. The activation energy and the preexponential factor of the reactant dissociation were obtained from a phenomenological model calculation. Results are presented in detail

Towards a common thermodynamic database for speciation models

International Nuclear Information System (INIS)

Lee, J. van der; Lomenech, C.

2004-01-01

Bio-geochemical speciation models and reactive transport models are reaching an operational stage, allowing simulation of complex dynamic experiments and description of field observations. For decades, the main focus has been on model performance but at present, the availability and reliability of thermodynamic data is the limiting factor of the models. Thermodynamic models applied to real and complex geochemical systems require much more extended thermodynamic databases with many minerals, colloidal phases, humic and fulvic acids, cementitious phases and (dissolved) organic complexing agents. Here we propose a methodological approach to achieve, ultimately, a common, operational database including the reactions and constants of these phases. Provided they are coherent with the general thermodynamic laws, sorption reactions are included as well. We therefore focus on sorption reactions and parameter values associated with specific sorption models. The case of sorption on goethite has been used to illustrate the way the methodology handles the problem of inconsistency and data quality. (orig.)

Development of thermodynamic databases for geochemical calculations

Energy Technology Data Exchange (ETDEWEB)

Arthur, R.C. [Monitor Scientific, L.L.C., Denver, Colorado (United States); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Neyama, Atsushi [Computer Software Development Corp., Tokyo (Japan)

1999-09-01

Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000degC. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25degC) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25degC and l bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100degC at 1 bar. All equilibrium constants, reaction enthalpies, and log K(T) coefficients in PHREEQE.JNC are calculated using SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT model, and because primary

Development of thermodynamic databases for geochemical calculations

International Nuclear Information System (INIS)

Arthur, R.C.; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu; Neyama, Atsushi

1999-09-01

Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000degC. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25degC) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25degC and l bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100degC at 1 bar. All equilibrium constants, reaction enthalpies, and log K(T) coefficients in PHREEQE.JNC are calculated using SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT model, and because primary

Dissociation in Psychiatric Disorders: A Meta-Analysis of Studies Using the Dissociative Experiences Scale.

Science.gov (United States)

Lyssenko, Lisa; Schmahl, Christian; Bockhacker, Laura; Vonderlin, Ruben; Bohus, Martin; Kleindienst, Nikolaus

2018-01-01

Dissociation is a complex, ubiquitous construct in psychopathology. Symptoms of dissociation are present in a variety of mental disorders and have been connected to higher burden of illness and poorer treatment response, and not only in disorders with high levels of dissociation. This meta-analysis offers a systematic and evidence-based study of the prevalence and distribution of dissociation, as assessed by the Dissociative Experiences Scale, within different categories of mental disorders, and it updates an earlier meta-analysis. More than 1,900 original publications were screened, and 216 were included in the meta-analysis, comprising 15,219 individuals in 19 diagnostic categories. The largest mean dissociation scores were found in dissociative disorders (mean scores >35), followed by posttraumatic stress disorder, borderline personality disorder, and conversion disorder (mean scores >25). Somatic symptom disorder, substance-related and addictive disorders, feeding and eating disorders, schizophrenia, anxiety disorder, OCD, and most affective disorders also showed mean dissociation scores >15. Bipolar disorders yielded the lowest dissociation scores (mean score, 14.8). The findings underline the importance of careful psychopathological assessment of dissociative symptoms in the entire range of mental disorders.

Exact analytical thermodynamic expressions for a Brownian heat engine

Science.gov (United States)

Taye, Mesfin Asfaw

2015-09-01

The nonequilibrium thermodynamics feature of a Brownian motor operating between two different heat baths is explored as a function of time t . Using the Gibbs entropy and Schnakenberg microscopic stochastic approach, we find exact closed form expressions for the free energy, the rate of entropy production, and the rate of entropy flow from the system to the outside. We show that when the system is out of equilibrium, it constantly produces entropy and at the same time extracts entropy out of the system. Its entropy production and extraction rates decrease in time and saturate to a constant value. In the long time limit, the rate of entropy production balances the rate of entropy extraction, and at equilibrium both entropy production and extraction rates become zero. Furthermore, via the present model, many thermodynamic theories can be checked.

Thermodynamic analysis of ANS binding to partially unfolded α-lactalbumin: correlation of endothermic to exothermic changeover with formation of authentic molten globules.

Science.gov (United States)

Kim, Ki Hyung; Yun, Soi; Mok, K H; Lee, E K

2016-09-01

A fluorescent reporter, 8-anilino-1-naphthalene sulfonic acid (ANS), can serve as a reference molecule for conformational transition of a protein because its aromatic carbons have strong affinity with hydrophobic cores of partially unfolded molten globules. Using a typical calcium-binding protein, bovine α-lactalbumin (BLA), as a model protein, we compared the ANS binding thermodynamics to the decalcified (10 mM EDTA treated) apo-BLA at two representative temperatures: 20 and 40 °C. This is because the authentic molten globule is known to form more heavily at an elevated temperature such as 40 °C. Isothermal titration calorimetry experiments revealed that the BLA-ANS interactions at both temperatures were entropy-driven, and the dissociation constants were similar on the order of 10(-4)  M, but there was a dramatic changeover in the binding thermodynamics from endothermic at 20 °C to exothermic at 40 °C. We believe that the higher subpopulation of authentic molten globules at 40 °C than 20 °C would be responsible for the results, which also indicate that weak binding is sufficient to alter the ANS binding mechanisms. We expect that the thermodynamic properties obtained from this study would serve as a useful reference for investigating the binding of other hydrophobic ligands such as oleic acid to apo-BLA, because oleic acid is known to have tumor-selective cytotoxicity when complexed with partially unfolded α-lactalbumin. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Simulation of Cu-Mg metallic glass: Thermodynamics and structure

DEFF Research Database (Denmark)

Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel

2004-01-01

We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from...... the melt at as slow a rate as practical, using constant temperature and pressure molecular dynamics. During the cooling process we have carried out thermodynamic analyses based on the temperature dependence of the enthalpy and its derivative, the specific heat, from which the glass transition temperature...

Constants of acid‒base equilibria in an aqueous amikacin aminoglycoside solution at 298 K

Science.gov (United States)

Alekseev, V. G.; Markova, E. V.

2016-03-01

The acid dissociation constants of form p K 1 = 7.34 ± 0.01, p K 2 = 7.84 ± 0.01, p K 3 = 8.77 ± 0.01, p K 4 = 9.49 ± 0.01, and p K 5 = 10.70 ± 0.02 of cationic amikacin are determined by pH-metric titration at 25°C against the background of 0.1 mol/L KNO3. K 1, K 2, K 3, and K 4 correspond to the dissociation of protons coordinated to amino groups, while K 5 characterizes the dissociation of the hydroxyl hydrogen atom, testifying to the amphoteric character of amikacin molecules. Applying density functional theory (DFT) with the B3LYP hybrid functional and the 6-311G**++ basis set, the partial charges on the atoms of an amikacin molecule are calculated. It is concluded that the dissociation of H(55)hydrogen atom occurs with a greatest partial charge of +0.53631.

Elastic constants from microscopic strain fluctuations

Science.gov (United States)

Sengupta; Nielaba; Rao; Binder

2000-02-01

Fluctuations of the instantaneous local Lagrangian strain epsilon(ij)(r,t), measured with respect to a static "reference" lattice, are used to obtain accurate estimates of the elastic constants of model solids from atomistic computer simulations. The measured strains are systematically coarse-grained by averaging them within subsystems (of size L(b)) of a system (of total size L) in the canonical ensemble. Using a simple finite size scaling theory we predict the behavior of the fluctuations as a function of L(b)/L and extract elastic constants of the system in the thermodynamic limit at nonzero temperature. Our method is simple to implement, efficient, and general enough to be able to handle a wide class of model systems, including those with singular potentials without any essential modification. We illustrate the technique by computing isothermal elastic constants of "hard" and "soft" disk triangular solids in two dimensions from Monte Carlo and molecular dynamics simulations. We compare our results with those from earlier simulations and theory.

Computer program for calculation of ideal gas thermodynamic data

Science.gov (United States)

Gordon, S.; Mc Bride, B. J.

1968-01-01

Computer program calculates ideal gas thermodynamic properties for any species for which molecular constant data is available. Partial functions and derivatives from formulas based on statistical mechanics are provided by the program which is written in FORTRAN 4 and MAP.

On the thermodynamic stability of the generalized Chaplygin gas

International Nuclear Information System (INIS)

Santos, F.C.; Bedran, M.L.; Soares, V.

2006-01-01

The main purpose of this Letter is to discuss the temperature behavior and the thermodynamic stability of an exotic fluid known as generalized Chaplygin gas considering only general thermodynamics. This fluid is considered a perfect fluid which obeys an adiabatic equation of state like P=-A/ρ α , where P and ρ are respectively the pressure and energy density; the parameter A is a positive universal constant and α>0. It is remarked that if the energy density of the fluid is a function of volume only, the temperature of the fluid remains zero at any pressure or volume, violating the third law of thermodynamics. We have determined a scenario where its thermal equation of state depends on temperature only and the fluid presents thermodynamic stability during any expansion process. Such a scenario also reveals that the fluid cools down through the expansion without facing any critical point or phase transition

Theoretical study of phonon dispersion, elastic, mechanical and thermodynamic properties of barium chalcogenides

Science.gov (United States)

Musari, A. A.; Orukombo, S. A.

2018-03-01

Barium chalcogenides are known for their high-technological importance and great scientific interest. Detailed studies of their elastic, mechanical, dynamical and thermodynamic properties were carried out using density functional theory and plane-wave pseudo potential method within the generalized gradient approximation. The optimized lattice constants were in good agreement when compared with experimental data. The independent elastic constants, calculated from a linear fit of the computed stress-strain function, were used to determine the Young’s modulus (E), bulk modulus (B), shear modulus (G), Poisson’s ratio (σ) and Zener’s anisotropy factor (A). Also, the Debye temperature and sound velocities for barium chalcogenides were estimated from the three independent elastic constants. The calculations of phonon dispersion showed that there are no negative frequencies throughout the Brillouin zone. Hence barium chalcogenides have dynamically stable NaCl-type crystal structure. Finally, their thermodynamic properties were calculated in the temperature range of 0-1000 K and their constant-volume specific heat capacities at room-temperature were reported.

Misuse of thermodynamics in the interpretation of isothermal titration calorimetry data for ligand binding to proteins.

Science.gov (United States)

Pethica, Brian A

2015-03-01

Isothermal titration calorimetry (ITC) has given a mass of data on the binding of small molecules to proteins and other biopolymers, with particular interest in drug binding to proteins chosen as therapeutic indicators. Interpretation of the enthalpy data usually follows an unsound protocol that uses thermodynamic relations in circumstances where they do not apply. Errors of interpretation include incomplete definitions of ligand binding and equilibrium constants and neglect of the non-ideality of the solutions under study, leading to unreliable estimates of standard free energies and entropies of binding. The mass of reported thermodynamic functions for ligand binding to proteins estimated from ITC enthalpies alone is consequently of uncertain thermodynamic significance and utility. ITC and related experiments to test the protocol assumptions are indicated. A thermodynamic procedure avoiding equilibrium constants or other reaction models and not requiring protein activities is given. The discussion draws attention to the fundamental but neglected relation between the thermodynamic activity and bioactivity of drugs and to the generally unknown thermodynamic status of ligand solutions, which for drugs relates directly to effective therapeutic dosimetry. Copyright © 2014 Elsevier Inc. All rights reserved.

Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor.

Science.gov (United States)

Gómez-Pérez, Lydia; López-Martínez, Alicia Eva; Asmundson, Gordon John Glenn

2013-11-30

Understanding which factors predict individual dissociative response during stressful situations is important to clarify the nature of dissociation and the mechanisms associated to its use as a coping strategy. The present study examined (1) whether experiential avoidance (EA), anxiety sensitivity (AS), depressive symptoms, and state anxiety concurrently predicted trait dissociation (TD)-absorption, amnesia, depersonalization, and total TD scores-and laboratory induced dissociation (LID); and (2) whether TD and catastrophizing predicted LID. We also examined whether catastrophizing mediated the relationships between both AS and depressive symptoms and LID. A total of 101 female undergraduate students participated in a cold pressor task, which significantly induced dissociation. Results of hierarchical regression analyses showed that AS at Time 1 (9 months before the experimental session), as well as depressive symptoms and catastrophizing at the time of the experiment (Time 2), predicted LID at Time 2. Depressive symptoms at Time 2 predicted total TD, absorption, and amnesia scores. AS at Time 1 and depressive symptoms at Time 2 predicted depersonalization. AS, depressive symptoms, and catastrophizing seem to facilitate the use of dissociative strategies by healthy individuals, even in response to non-traumatic but discomforting stress. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Small Systems and Limitations on the Use of Chemical Thermodynamics

Science.gov (United States)

Tovbin, Yu. K.

2018-01-01

Limitations on using chemical thermodynamics to describe small systems are formulated. These limitations follow from statistical mechanics for equilibrium and nonequilibrium processes and reflect (1) differences between characteristic relaxation times in momentum, energy, and mass transfer in different aggregate states of investigated systems; (2) achievements of statistical mechanics that allow us to determine criteria for the size of smallest region in which thermodynamics can be applied and the scale of the emergence of a new phase, along with criteria for the conditions of violating a local equilibrium. Based on this analysis, the main thermodynamic results are clarified: the phase rule for distorted interfaces, the sense and area of applicability of Gibbs's concept of passive forces, and the artificiality of Kelvin's equation as a result of limitations on the thermodynamic approach to considering small bodies. The wrongness of introducing molecular parameters into thermodynamic derivations, and the activity coefficient for an activated complex into the expression for a reaction rate constant, is demonstrated.

Corrosion Thermodynamics of Magnesium and Alloys from First Principles as a Function of Solvation

Science.gov (United States)

Limmer, Krista; Williams, Kristen; Andzelm, Jan

Thermodynamics of corrosion processes occurring on magnesium surfaces, such as hydrogen evolution and water dissociation, have been examined with density functional theory (DFT) to evaluate the effect of impurities and dilute alloying additions. The modeling of corrosion thermodynamics requires examination of species in a variety of chemical and electronic states in order to accurately represent the complex electrochemical corrosion process. In this study, DFT calculations for magnesium corrosion thermodynamics were performed with two DFT codes (VASP and DMol3), with multiple exchange-correlation functionals for chemical accuracy, as well as with various levels of implicit and explicit solvation for surfaces and solvated ions. The accuracy of the first principles calculations has been validated against Pourbaix diagrams constructed from solid, gas and solvated charged ion calculations. For aqueous corrosion, it is shown that a well parameterized implicit solvent is capable of accurately representing all but the first coordinating layer of explicit water for charged ions.

Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

KAUST Repository

Gan, Liyong

2013-08-20

Exfoliated two-dimensional early transition metal carbides and carbonitrides are usually not terminated by metal atoms but saturated by O, OH, and/or F, thus making it difficult to understand the surface structure evolution and the induced electronic modifications. To fill this gap, density functional theory and molecular dynamics simulations are performed to capture the initial stage of the oxidation process of Ti2C, a prototypical example from the recently fabricated class of two-dimensional carbides and carbonitrides. It is shown that the unsaturated Ti 3d orbitals of the pristine Ti2C surface interact strongly with the approaching O2 molecules, resulting in barrierless O2 dissociation. The diffusion of the dissociated O atoms is also found to be very facile. Molecular dynamics simulations suggest that both dissociation and diffusion are enhanced as the O2 coverage increases to 0.25 monolayer. For a coverage of less than 0.11 monolayer, the adsorbates lead to a minor modification of the electronic properties of Ti2C, while the modification is remarkable at 0.25 monolayer. The formed Ti2CO2 after O saturation is an indirect narrow gap semiconductor (0.33 eV) with high intrinsic carrier concentration at room temperature and high thermodynamic stability at intermediate temperature (e.g., 550 °C).

Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

KAUST Repository

Gan, Liyong; Huang, Dan; Schwingenschlö gl, Udo

2013-01-01

Exfoliated two-dimensional early transition metal carbides and carbonitrides are usually not terminated by metal atoms but saturated by O, OH, and/or F, thus making it difficult to understand the surface structure evolution and the induced electronic modifications. To fill this gap, density functional theory and molecular dynamics simulations are performed to capture the initial stage of the oxidation process of Ti2C, a prototypical example from the recently fabricated class of two-dimensional carbides and carbonitrides. It is shown that the unsaturated Ti 3d orbitals of the pristine Ti2C surface interact strongly with the approaching O2 molecules, resulting in barrierless O2 dissociation. The diffusion of the dissociated O atoms is also found to be very facile. Molecular dynamics simulations suggest that both dissociation and diffusion are enhanced as the O2 coverage increases to 0.25 monolayer. For a coverage of less than 0.11 monolayer, the adsorbates lead to a minor modification of the electronic properties of Ti2C, while the modification is remarkable at 0.25 monolayer. The formed Ti2CO2 after O saturation is an indirect narrow gap semiconductor (0.33 eV) with high intrinsic carrier concentration at room temperature and high thermodynamic stability at intermediate temperature (e.g., 550 °C).

General concept of a gas engine for a hybrid vehicle, operating on methanol dissociation products

International Nuclear Information System (INIS)

Tartakovsky, L.; Aleinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Schindler, Y.; Zvirin, Y.

1998-01-01

The paper presents a general concept of a hybrid propulsion system, based on an SI internal combustion engine fueled by methanol dissociation products (MDP). The proposed hybrid propulsion scheme is a series hybrid, which allows the engine to be operated in an on-off mode at constant optimal regime. The engine is fed by gaseous products of methanol dissociation (mainly hydrogen and carbon monoxide) emerging from an on-board catalytic reformer. The general scheme and base operation features of the propulsion system are described. The benefits that may be achieved by combining the well-known idea of on-board methanol dissociation with the hybrid vehicle concept are discussed. The proposed scheme is compared with those of systems operating on gasoline, liquid methanol, hydrogen and also with the multi-regime (not hybrid) engine fed by MDP

Direct measurements of methoxy removal rate constants for collisions with CH4, Ar, N2, Xe, and CF4 in the temperature range 673--973K

International Nuclear Information System (INIS)

Wantuck, P.J.; Oldenborg, R.C.; Baugchum, S.L.; Winn, K.R.

1988-01-01

Removal rate constants for CH 3 O by CH 4 , Ar, N 2 , Xe, and CF 4 were measured over a 400K temperature range using a laser photolysis/laser-induced fluorescence technique. Rapid methoxy removal rates are observed for the non-reactive collision partners (Ar, N 2 , Xe, and CF 4 ) at elevated temperatures showing that the dissociation and isomerization channels for CH 3 O are indeed important. The total removal rate constant (reaction /plus/ dissociation and/or isomerization) for CH 4 exhibits a linear dependence on temperature and has a removal rate constant, k/sub r/ /equals/ (1.2 +- 0.6) /times/ 10/sup /minus/8/exp[(/minus/101070 +- 350)/T]cm 3 molecule/sup /minus/1/s/sup /minus/1/. Assuming that the removal rate constant due to dissociation and/or isomerization are similar for CH 4 and CF 4 , the reaction rate constant for CH 3 O /plus/ CH 4 is equal to (1.7 +- 1.0) /times/ 10/sup /minus/10/exp[(/minus/7480 +- 1100)/T]cm 3 molecule/sup /minus/1/s/sup /minus/1/. 7 refs., 4 figs

Three dimensions of dissociative amnesia.

Science.gov (United States)

Dell, Paul F

2013-01-01

Principal axis factor analysis with promax rotation extracted 3 factors from the 42 memory and amnesia items of the Multidimensional Inventory of Dissociation (MID) database (N = 2,569): Discovering Dissociated Actions, Lapses of Recent Memory and Skills, and Gaps in Remote Memory. The 3 factors' shared variance ranged from 36% to 64%. Construed as scales, the 3 factor scales had Cronbach's alpha coefficients of .96, .94, and .93, respectively. The scales correlated strongly with mean Dissociative Experiences Scale scores, mean MID scores, and total scores on the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R). What is interesting is that the 3 amnesia factors exhibited a range of correlations with SCID-D-R Amnesia scores (.52, .63, and .70, respectively), suggesting that the SCID-D-R Amnesia score emphasizes gaps in remote memory over amnesias related to dissociative identity disorder. The 3 amnesia factor scales exhibited a clinically meaningful pattern of significant differences among dissociative identity disorder, dissociative disorder not otherwise specified-1, dissociative amnesia, depersonalization disorder, and nonclinical participants. The 3 amnesia factors may have greater clinical utility for frontline clinicians than (a) amnesia as discussed in the context of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nosology of the dissociative disorders or (b) P. Janet's (1893/1977 ) 4-fold classification of dissociative amnesia. The author recommends systematic study of the phenomenological differences within specific dissociative symptoms and their differential relationship to specific dissociative disorders.

Light cone thermodynamics

Science.gov (United States)

De Lorenzo, Tommaso; Perez, Alejandro

2018-02-01

We show that null surfaces defined by the outgoing and infalling wave fronts emanating from and arriving at a sphere in Minkowski spacetime have thermodynamical properties that are in strict formal correspondence with those of black hole horizons in curved spacetimes. Such null surfaces, made of pieces of light cones, are bifurcate conformal Killing horizons for suitable conformally stationary observers. They can be extremal and nonextremal depending on the radius of the shining sphere. Such conformal Killing horizons have a constant light cone (conformal) temperature, given by the standard expression in terms of the generalization of surface gravity for conformal Killing horizons. Exchanges of conformally invariant energy across the horizon are described by a first law where entropy changes are given by 1 /(4 ℓp2) of the changes of a geometric quantity with the meaning of horizon area in a suitable conformal frame. These conformal horizons satisfy the zeroth to the third laws of thermodynamics in an appropriate way. In the extremal case they become light cones associated with a single event; these have vanishing temperature as well as vanishing entropy.

The evaluation of some thermodynamic parameters by RIA method

International Nuclear Information System (INIS)

Dorobantu, I. I.; Cucu Delia-Irina

2001-01-01

The present paper evaluates some of thermodynamic parameters by using RIA (radioimmunoassay) method. The RIA systems studied were: 1) antiprogesterone antibody-progesterone- 3 H; 2) antiprogesterone antibody-progesterone- 125 I. The antigen (progesterone) was labelled with 3 H, in the first case, and 125 I in the second one (progesterone- 125 I was progesterone-6-S-CH 2 -CO-histamine- 125 I). RIA reactions were developed at two temperatures: 277 K and 296 K. Samples of antiprogesterone antibodies and labelled progesterone were incubated with different amounts of unlabeled progesterone. The immune complex was precipitated after reaching the chemical equilibrium and its radioactivity measured at γ-counter. By the radioactive measurements, the affinity constants (K S ) were estimated. The values of the affinity constants were used to estimate the thermodynamic parameters of the systems, such as: enthalpy (ΔH), Gibbs energy (ΔG) and entropy (ΔS). (authors)

From dissociation to trauma? Individual differences in dissociation as predictor of 'trauma' perception

NARCIS (Netherlands)

Rassin, Eric; van Rootselaar, Anne-Fleur

2006-01-01

In clinical literature, dissociative complaints are generally considered to be the result of traumatic experiences. However, it has been argued that dissociative complaints, in turn, may indulge over-reporting of traumatic experiences. Hence, correlations between dissociation and self-reported

Dissociation of dilute immiscible copper alloy thin films

International Nuclear Information System (INIS)

Barmak, K.; Lucadamo, G. A.; Cabral, C. Jr.; Lavoie, C.; Harper, J. M. E.

2000-01-01

The dissociation behavior of dilute, immiscible Cu-alloy thin films is found to fall into three broad categories that correlate most closely with the form of the Cu-rich end of the binary alloy phase diagrams. Available thermodynamic and tracer diffusion data shed further light on alloy behavior. Eight alloying elements were selected for these studies, with five elements from groups 5 and 6, two from group 8, and one from group 11 of the periodic table. They are respectively V, Nb, Ta, Cr, Mo, Fe, Ru, and Ag. The progress of precipitation in approximately 500-nm-thick alloy films, containing 2.5-3.8 at. % solute, was followed with in situ resistance and stress measurements as well as with in situ synchrotron x-ray diffraction. In addition, texture analysis and transmission electron microscopy were used to investigate the evolution of microstructure and texture of Cu(Ta) and Cu(Ag). For all eight alloys, dissociation occurred upon heating, with the rejection of solute and evolution of microstructure often occurring in multiple steps that range over several hundred degrees between approximately 100 and 900 degree sign C. However, in most cases, substantial reductions in resistivity of the films took place below 400 degree sign C, at temperatures of interest to copper metallization schemes for silicon chip technology. (c) 2000 American Institute of Physics

Effects of chirping on the dissociation dynamics of H2 in a two-frequency laser field

International Nuclear Information System (INIS)

Datta, Avijit; Bhattacharyya, S.S.; Kim, Bongsoo

2002-01-01

We present the effects of frequency chirping of laser pulses on (1+1)-photon resonance-enhanced dissociation dynamics of H 2 . The dissociation occurs via two closely spaced nonadiabatically coupled intermediate levels which are in one-photon resonance or near resonance with the initial level. Predissociating levels embedded into continua are considered. When the first laser field is sufficiently intense and suitably chirped, the dissociation probability is enhanced by adiabatic rapid passage through the avoided crossing arising from the frequency swept radiative interaction. The whole population of the ground level can be effectively transferred to the intermediate levels by this technique facilitating the dissociation process by the second field. We also report the effect of frequency detuning and chirp width on the dissociation probability. Widths of the two peaks of the dissociation line shape increase with an increase in chirp width, resulting in the possibility of control in the dissociation yield. When the first field is a laser pulse of low intensity and constant frequency and the second laser frequency is chirped, predissociating levels take important parts in the dissociation dynamics and we obtain a signature of the nonadiabatic effect of the first step on the second step of photodissociation dynamics. This feature is due to the presence of the predissociating levels and the nonadiabatic mixing of two intermediate levels. All these results can be explained in terms of the adiabatic dressed levels

Assessment of complex dissociative disorder patients and simulated dissociation in forensic contexts.

Science.gov (United States)

Brand, Bethany L; Webermann, Aliya R; Frankel, A Steven

Few assessors receive training in assessing dissociation and complex dissociative disorders (DDs). Potential differential diagnoses include anxiety, mood, psychotic, substance use, and personality disorders, as well as exaggeration and malingering. Individuals with DDs typically elevate on many clinical and validity scales on psychological tests, yet research indicates that they can be distinguished from DD simulators. Becoming informed about the testing profiles of DD individuals and DD simulators can improve the accuracy of differential diagnoses in forensic settings. In this paper, we first review the testing profiles of individuals with complex DDs and contrast them with DD simulators on assessment measures used in forensic contexts, including the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Personality Assessment Inventory (PAI), and the Structured Inventory of Reported Symptoms (SIRS), as well as dissociation-specific measures such as the Dissociative Experiences Scale (DES) and Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D-R). We then provide recommendations for assessing complex trauma and dissociation through the aforementioned assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Are We There Yet? Applying Thermodynamic and Kinetic Profiling on Embryonic Ectoderm Development (EED) Hit-to-Lead Program.

Science.gov (United States)

Wang, Ying; Edalji, Rohinton P; Panchal, Sanjay C; Sun, Chaohong; Djuric, Stevan W; Vasudevan, Anil

2017-10-26

It is advocated that kinetic and thermodynamic profiling of bioactive compounds should be incorporated and utilized as complementary tools for hit and lead optimizations in drug discovery. To assess their applications in the EED hit-to-lead optimization process, large amount of thermodynamic and kinetic data were collected and analyzed via isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR), respectively. Slower dissociation rates (k off ) of the lead compounds were observed as the program progressed. Analysis of the kinetic data indicated that compound cellular activity correlated with both K i and k off . Our analysis revealed that ITC data should be interpreted in the context of chiral purity of the compounds. The thermodynamic signatures of the EED aminopyrrolidine compounds were found to be mainly enthalpy driven with improved enthalpic contributions as the program progressed. Our study also demonstrated that significant challenges still exist in utilizing kinetic and thermodynamic parameters for hit selection.

Technical Work Plan for: Thermodynamic Databases for Chemical Modeling

International Nuclear Information System (INIS)

C.F. Jovecolon

2006-01-01

The objective of the work scope covered by this Technical Work Plan (TWP) is to correct and improve the Yucca Mountain Project (YMP) thermodynamic databases, to update their documentation, and to ensure reasonable consistency among them. In addition, the work scope will continue to generate database revisions, which are organized and named so as to be transparent to internal and external users and reviewers. Regarding consistency among databases, it is noted that aqueous speciation and mineral solubility data for a given system may differ according to how solubility was determined, and the method used for subsequent retrieval of thermodynamic parameter values from measured data. Of particular concern are the details of the determination of ''infinite dilution'' constants, which involve the use of specific methods for activity coefficient corrections. That is, equilibrium constants developed for a given system for one set of conditions may not be consistent with constants developed for other conditions, depending on the species considered in the chemical reactions and the methods used in the reported studies. Hence, there will be some differences (for example in log K values) between the Pitzer and ''B-dot'' database parameters for the same reactions or species

Thermodynamic parameters and transport coefficients of the U-C-F gas mixture in the steady flow gaseous core fission reactor

International Nuclear Information System (INIS)

Berg, M.S. van den.

1995-01-01

Thermodynamic parameters and transport coefficients have been calculated for a multicomponent reacting U-C-F gas mixture in the steady flow gaseous core fission reactor. Element abundances are consistent with thermodynamic equilibrium between the gas mixture and a cooled solid graphite wall at 2500 K. Results are presented for various pressures, a fluorine potential of 5.6 and temperatures between 2500 and 7000 K. As a result of dissociation processes of uranium and carbon fluoride compounds, ''effective'' values of thermodynamic parameters and transport coefficients show anomalous behaviour with respect to so-called ''frozen'' values. The chemical reaction energy of the U-C-F gas mixture has been calculated as the driving-force behind the process of fuel redistribution to attain criticality conditions inside a functioning reactor. (author)

Foliation and the first law of black hole thermodynamics

International Nuclear Information System (INIS)

Siddiqui, Azad A.; Riaz, Syed Muhammad Jawwad; Akbar, M.

2011-01-01

There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime. It has been shown earlier that for different spacetimes, the Einstein field equations at the horizon can be expressed as the first law of black hole thermodynamics. Using the idea of foliation, we develop a simpler procedure to obtain such results. We consider r = constant slices, for the Schwarzschild and Reissner-Nordstrom black hole spacetimes. The Einstein field equations for the induced 3-dimensional metrics of the hypersurfaces are expressed in thermodynamic quantities under the virtual displacements of the hypersurfaces. As expected, it is found that the field equations of the induced metric corresponding to the horizon can be written as a first law of black hole thermodynamics. It is to be mentioned here that our procedure is much easier, to obtain such results, as here one has to essentially deal with (n - 1)-dimensional induced metric for an n-dimensional spacetime. (authors)

Foliation and the First Law of Black Hole Thermodynamics

International Nuclear Information System (INIS)

Siddiqui, Azad A.; Riaz, Syed Muhammad Jawwad; Akbar, M.

2011-01-01

There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime. It has been shown earlier that for different spacetimes, the Einstein field equations at the horizon can be expressed as the first law of black hole thermodynamics. Using the idea of foliation, we develop a simpler procedure to obtain such results. We consider r = constant slices, for the Schwarzschild and Reissner—Nordstrom black hole spacetimes. The Einstein field equations for the induced 3-dimensional metrics of the hypersurfaces are expressed in thermodynamic quantities under the virtual displacements of the hypersurfaces. As expected, it is found that the field equations of the induced metric corresponding to the horizon can be written as a first law of black hole thermodynamics. It is to be mentioned here that our procedure is much easier, to obtain such results, as here one has to essentially deal with (n — 1)-dimensional induced metric for an n-dimensional spacetime. (general)

Rates and equilibrium constants of the ligand-induced conformational transition of an HCN ion channel protein domain determined by DEER spectroscopy.

Science.gov (United States)

Collauto, Alberto; DeBerg, Hannah A; Kaufmann, Royi; Zagotta, William N; Stoll, Stefan; Goldfarb, Daniella

2017-06-14

Ligand binding can induce significant conformational changes in proteins. The mechanism of this process couples equilibria associated with the ligand binding event and the conformational change. Here we show that by combining the application of W-band double electron-electron resonance (DEER) spectroscopy with microfluidic rapid freeze quench (μRFQ) it is possible to resolve these processes and obtain both equilibrium constants and reaction rates. We studied the conformational transition of the nitroxide labeled, isolated carboxy-terminal cyclic-nucleotide binding domain (CNBD) of the HCN2 ion channel upon binding of the ligand 3',5'-cyclic adenosine monophosphate (cAMP). Using model-based global analysis, the time-resolved data of the μRFQ DEER experiments directly provide fractional populations of the open and closed conformations as a function of time. We modeled the ligand-induced conformational change in the protein using a four-state model: apo/open (AO), apo/closed (AC), bound/open (BO), bound/closed (BC). These species interconvert according to AC + L ⇌ AO + L ⇌ BO ⇌ BC. By analyzing the concentration dependence of the relative contributions of the closed and open conformations at equilibrium, we estimated the equilibrium constants for the two conformational equilibria and the open-state ligand dissociation constant. Analysis of the time-resolved μRFQ DEER data gave estimates for the intrinsic rates of ligand binding and unbinding as well as the rates of the conformational change. This demonstrates that DEER can quantitatively resolve both the thermodynamics and the kinetics of ligand binding and the associated conformational change.

Dissociative diffusion mechanism in vacancy-rich materials according to mass action kinetics

Directory of Open Access Journals (Sweden)

N. J. Biderman

2016-05-01

Full Text Available Two sets of diffusion-reaction numerical simulations using a finite difference method (FDM were conducted to investigate fast impurity diffusion via interstitial sites in vacancy-rich materials such as Cu(In,GaSe2 (CIGS and Cu2ZnSn(S, Se4 (CZTSSe or CZTS via the dissociative diffusion mechanism where the interstitial diffuser ultimately reacts with a vacancy to produce a substitutional. The first set of simulations extends the standard interstitial-limited dissociative diffusion theory to vacancy-rich material conditions where vacancies are annihilated in large amounts, introducing non-equilibrium vacancy concentration profiles. The second simulation set explores the vacancy-limited dissociative diffusion where impurity incorporation increases the equilibrium vacancy concentration. In addition to diffusion profiles of varying concentrations and shapes that were obtained in all simulations, some of the profiles can be fitted with the constant- and limited-source solutions of Fick’s second law despite the non-equilibrium condition induced by the interstitial-vacancy reaction. The first set of simulations reveals that the dissociative diffusion coefficient in vacancy-rich materials is inversely proportional to the initial vacancy concentration. In the second set of numerical simulations, impurity-induced changes in the vacancy concentration lead to distinctive diffusion profile shapes. The simulation results are also compared with published data of impurity diffusion in CIGS. According to the characteristic properties of diffusion profiles from the two set of simulations, experimental detection of the dissociative diffusion mechanism in vacancy-rich materials may be possible.

Equilibrium thermodynamics in modified gravitational theories

International Nuclear Information System (INIS)

Bamba, Kazuharu; Geng, C.-Q.; Tsujikawa, Shinji

2010-01-01

We show that it is possible to obtain a picture of equilibrium thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density f(R,φ,X), where R is the Ricci scalar and X is the kinetic energy of a scalar field φ. This comes from a suitable definition of an energy-momentum tensor of the 'dark' component that respects to a local energy conservation in the Jordan frame. In this framework the horizon entropy S corresponding to equilibrium thermodynamics is equal to a quarter of the horizon area A in units of gravitational constant G, as in Einstein gravity. For a flat cosmological background with a decreasing Hubble parameter, S globally increases with time, as it happens for viable f(R) inflation and dark energy models. We also show that the equilibrium description in terms of the horizon entropy S is convenient because it takes into account the contribution of both the horizon entropy S in non-equilibrium thermodynamics and an entropy production term.

Dissociation in small molecules

International Nuclear Information System (INIS)

Dehmer, P.M.

1982-01-01

The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

Use of an exchange method to estimate the association and dissociation rate constants of cadmium complexes formed with low-molecular-weight organic acids commonly exuded by plant roots.

Science.gov (United States)

Schneider, André; Nguyen, Christophe

2011-01-01

Organic acids released from plant roots can form complexes with cadmium (Cd) in the soil solution and influence metal bioavailability not only due to the nature and concentration of the complexes but also due to their lability. The lability of a complex influences its ability to buffer changes in the concentration of free ions (Cd); it depends on the association (, m mol s) and dissociation (, s) rate constants. A resin exchange method was used to estimate and (m mol s), which is the conditional estimate of depending on the calcium (Ca) concentration in solution. The constants were estimated for oxalate, citrate, and malate, three low-molecular-weight organic acids commonly exuded by plant roots and expected to strongly influence Cd uptake by plants. For all three organic acids, the and estimates were around 2.5 10 m mol s and 1.3 × 10 s, respectively. Based on the literature, these values indicate that the Cd- low-molecular-weight organic acids complexes formed between Cd and low-molecular-weight organic acids may be less labile than complexes formed with soil soluble organic matter but more labile than those formed with aminopolycarboxylic chelates. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Dissociation and homoconjugation equilibria of some acids and bases in N,N-dimethylformamide.

Science.gov (United States)

Roletto, E; Vanni, A

1977-01-01

The following monoprotic acids have been studied in N,N-dimethylformamide (DMF): p-toluenesulphonic acid; 2,6-dichlorobenzoic acid; 2,5-dichlorophenol; the anilinium ion; the N-methyl-anilinium ion. The first dissociation step of malonic and succinic acids has also been studied. Dissociation and homoconjugation constants have been determined potentiometrically, at 25 degrees , in buffer solutions containing either the acid and its tetraethylammonium salt or the base and its picrate. Homoconjugation equilibria between unchanged acid and univalent conjugate base have been found not only for benzoic acid and phenol derivatives, but also between undissociated diprotic carboxylic acids and the corresponding monoanions, which are strongly intramolecularly hydrogen-bonded. Results are discussed with reference to previously published values.

Solid and liquid Equation of state for initially porous aluminum where specific heat is constant

Science.gov (United States)

Forbes, Jerry W.; Lemar, E. R.; Brown, Mary

2011-06-01

A porous solid's initial state is off the thermodynamic surface of the non-porous solid to start with but when pressure is high enough to cause total pore collapse or crush up, then the final states are on the condensed matter thermodynamic surfaces. The Hugoniot for the fully compacted solid is above the Principle Hugoniot with pressure, temperature and internal energy increased at a given v. There are a number of ways to define this hotter Hugoniot, which can be referenced to other thermodynamic paths on this thermodynamic surface. The choice here was to use the Vinet isotherm to define a consistent thermodynamic surface for the solid and melt phase of 6061 aluminum where specific heat is constant for the P-v-T space of interest. Analytical equations are developed for PH and TH.

Simulant molecules with trivalent or pentavalent phosphorus atoms: bond dissociation energies and other thermodynamic and structural properties from quantum chemical models.

Science.gov (United States)

Hahn, David K; RaghuVeer, Krishans S; Ortiz, J V

2011-08-04

The CBS-QB3 and G4 thermochemical models have been used to generate energetic, structural, and spectroscopic data on a set of molecules with trivalent or pentavalent phosphorus atoms that can serve as simulants of chemical warfare agents. Based on structural data, the conformational stabilities of these molecules are explained in terms of the anomeric interaction within the OPOC and OPSC fragments. For those cases where experimental data are available, comparisons have been made between calculated and previously reported vibrational frequencies. All varieties of bond dissociation energies have been examined except those for C-H and P═O bonds. In trivalent phosphorus molecules, the O-C and S-C bonds have the lowest dissociation energies. In the pentavalent phosphorus set, the S-C bonds, followed by P-S bonds, have the lowest dissociation energies. In the fluorinated simulant molecules, the P-F bond is strongest, and the P-C or O-C bonds are weakest. © 2011 American Chemical Society

Thermodynamic stability of asymptotically anti-de Sitter rotating black holes in higher dimensions

International Nuclear Information System (INIS)

Dolan, Brian P

2014-01-01

Conditions for thermodynamic stability of asymptotically anti-de Sitter (AdS) rotating black holes in D-dimensions are determined. Local thermodynamic stability requires not only positivity conditions on the specific heat and the moment of inertia tensor but it is also necessary that the adiabatic compressibility be positive. It is shown that, in the absence of a cosmological constant, neither rotation nor charge is sufficient to ensure full local thermodynamic stability of a black hole. Thermodynamic stability properties of AdS Myers–Perry black holes are investigated for both singly spinning and multi-spinning black holes. Simple expressions are obtained for the specific heat and moment of inertia tensor in any dimension. An analytic expression is obtained for the boundary of the region of parameter space in which such space-times are thermodynamically stable. (paper)

Childhood Traumatic Experiences, Dissociative Symptoms, and Dissociative Disorder Comorbidity Among Patients With Panic Disorder: A Preliminary Study.

Science.gov (United States)

Ural, Cenk; Belli, Hasan; Akbudak, Mahir; Tabo, Abdulkadir

2015-01-01

This study assessed childhood trauma history, dissociative symptoms, and dissociative disorder comorbidity in patients with panic disorder (PD). A total of 92 psychotropic drug-naive patients with PD, recruited from outpatient clinics in the psychiatry department of a Turkish hospital, were involved in the study. Participants were assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), Dissociation Questionnaire, Panic and Agoraphobia Scale, Panic Disorder Severity Scale, and Childhood Trauma Questionnaire. Of the patients with PD, 18 (19%) had a comorbid dissociative disorder diagnosis on screening with the SCID-D. The most prevalent disorders were dissociative disorder not otherwise specified, dissociative amnesia, and depersonalization disorders. Patients with a high degree of dissociation symptoms and dissociative disorder comorbidity had more severe PD than those without (p dissociation and PD. Among all of the subscales, the strongest relationship was with childhood emotional abuse. Logistic regression analysis showed that emotional abuse and severity of PD were independently associated with dissociative disorder. In our study, a significant proportion of the patients with PD had concurrent diagnoses of dissociative disorder. We conclude that the predominance of PD symptoms at admission should not lead the clinician to overlook the underlying dissociative process and associated traumatic experiences among these patients.

Review and recommended thermodynamic properties of FeCO3

DEFF Research Database (Denmark)

Fosbøl, Philip Loldrup; Thomsen, Kaj; Stenby, Erling Halfdan

2010-01-01

An extensive review of entropy, enthalpy of formation and Gibbs energy of formation, heat capacity, aqueous solubility and solubility constant of FeCO3 is given. A consistent set of thermodynamic properties for FeCO3 and relevant aqeous species is selected and recommended for use. Speciation...

Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

OpenAIRE

Belli, Hasan

2014-01-01

Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative expe...

[Dissociative disorders and affective disorders].

Science.gov (United States)

Montant, J; Adida, M; Belzeaux, R; Cermolacce, M; Pringuey, D; Da Fonseca, D; Azorin, J-M

2014-12-01

The phenomenology of dissociative disorders may be complex and sometimes confusing. We describe here two cases who were initially misdiagnosed. The first case concerned a 61 year-old woman, who was initially diagnosed as an isolated dissociative fugue and was actually suffering from severe major depressive episode. The second case concerned a 55 year-old man, who was suffering from type I bipolar disorder and polyvascular disease, and was initially diagnosed as dissociative fugue in a mooddestabilization context, while it was finally a stroke. Yet dissociative disorders as affective disorder comorbidity are relatively unknown. We made a review on this topic. Dissociative disorders are often studied through psycho-trauma issues. Litterature is rare on affective illness comorbid with dissociative disorders, but highlight the link between bipolar and dissociative disorders. The later comorbidity often refers to an early onset subtype with also comorbid panic and depersonalization-derealization disorder. Besides, unipolar patients suffering from dissociative symptoms have more often cyclothymic affective temperament. Despite the limits of such studies dissociative symptoms-BD association seems to correspond to a clinical reality and further works on this topic may be warranted. Copyright © 2014 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

Chemical equilibrium. [maximizing entropy of gas system to derive relations between thermodynamic variables

Science.gov (United States)

1976-01-01

The entropy of a gas system with the number of particles subject to external control is maximized to derive relations between the thermodynamic variables that obtain at equilibrium. These relations are described in terms of the chemical potential, defined as equivalent partial derivatives of entropy, energy, enthalpy, free energy, or free enthalpy. At equilibrium, the change in total chemical potential must vanish. This fact is used to derive the equilibrium constants for chemical reactions in terms of the partition functions of the species involved in the reaction. Thus the equilibrium constants can be determined accurately, just as other thermodynamic properties, from a knowledge of the energy levels and degeneracies for the gas species involved. These equilibrium constants permit one to calculate the equilibrium concentrations or partial pressures of chemically reacting species that occur in gas mixtures at any given condition of pressure and temperature or volume and temperature.

Derivatives of imidopyrophosphoric acids as extractants. Part I. The preparation and fundamental constants of tetraalkylimidopyrophosphoric acids

International Nuclear Information System (INIS)

Preez, J.G.H. du; Knabl, K.U.; Krueger, L.; Brecht, B.J.A.M. van

1992-01-01

Improved methods for the preparation of imidotetraalkylpyrophosphates are reported. The dissociation constant of the water soluble tetraethyl analogue was determined by potentiometric titration. The values for the partition constant and aggregation constant of the tetradodecyl analogue were determined by two phase EMF potentiometric titration of which the data were processed through a sophisticated general optimization technique. The application of this method also made it possible to obtain a species distribution curve of the organic phase in terms of variation of pH in the aqueous phase. 17 refs., 7 figs., 4 tabs

Synthesis, Acidity Constants and Tautomeric Structure of the Diazonium Coupling Products of 2-(Benzylsulfanyl-7H-purin-6-one in Its Ground and Excited States

Directory of Open Access Journals (Sweden)

Hosam A. Saad

2011-10-01

Full Text Available A series of new 8-arylhydrazono-2-(benzylsulfanyl-7H-purin-6-ones 6 were synthesized, their electronic absorption spectra in different organic solvents of varying polarities were investigated and their acid dissociation constants in both the ground and excited states were determined spectrophotometrically. The tautomeric structures of such products were elucidated by spectral analyses and correlation of their acid dissociation constants with the Hammett equation. The results indicated that the studied compounds 6 exist predominantly in the hydrazone tautomeric form 6A in both the ground and excited states.

The co-occurrence of PTSD and dissociation: differentiating severe PTSD from dissociative-PTSD

DEFF Research Database (Denmark)

Armour, C.; Karstoft, K. I.; Richardson, J. D.

2014-01-01

A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD....... The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD. The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants...... were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity scores were created reflecting the sum of the frequency and intensity items from each of the 17 PTSD and 3 dissociation items. The CAPS severity...

Dissociation and Memory Fragmentation in Posttraumatic Stress Disorder: An Evaluation of the Dissociative Encoding Hypothesis

Science.gov (United States)

Bedard-Gilligan, Michele; Zoellner, Lori A.

2012-01-01

Several prominent theories of posttraumatic stress disorder (PTSD) posit that peritraumatic dissociation results in insufficient encoding of the trauma memory and that persistent dissociation prevents memory elaboration, resulting in memory fragmentation and PTSD. In this review, we summarize the empirical literature on peritraumatic and trait dissociation and trauma narrative fragmentation as measured by meta-memory and rater/objective coding. Across 16 studies to date, the association between dissociation and fragmentation was most prominent when examining peritraumatic dissociation and patient's own ratings of memory fragmentation. This relationship did not hold when examining trait dissociation or rater-coded or computer-generated measures of fragmentation. Thus, initial evidence points more toward a strong self-reported association between constructs that is not supported on more objective fragmentation coding. Measurement overlap, construct ambiguity, and exclusion of potential confounds may underlie lack of a strong association between dissociation and objective-rated fragmentation. PMID:22348400

[Screening for major dissociative disorders with the FDS, the German version of the Dissociative Experience Scale].

Science.gov (United States)

Rodewald, Frauke; Gast, Ursula; Emrich, Hinderk M

2006-06-01

The prevalence of major dissociative disorders (dissociative identity disorder, DID and similar forms of dissociative disorder not otherwise specified, DDNOS) in clinical samples is about 5 %. Despite their frequency, major dissociative disorders are often overseen for a long time. Screening-scales have proved to be effective to support clinical diagnosis. The aim of this study was to test, whether the Fragebogen für dissoziative Symptome (FDS), the German version of the Dissociative Experiences Scale (DES), differentiates between patients with dissociative disorders, non-dissociative disorders and non-clinical controls. Additionally, an optimal FDS-cutoff for a more detailed differential-diagnostic evaluation of the dissociative symptomatology should be identified. 150 participants with DID (group DID: n = 44), DDNOS (DDNOS: n = 22), posttraumatic disorders (TRAUMA: n = 20), other non-dissociative disorders (non-TRAUMA: n = 34) and non-clinical controls (KG: n = 30) completed the FDS. In the five diagnostic groups, mean values were calculated and compared for the FDS, DES and FDS-20. Via receiver-operating-curves the cutoff-scores, which differentiated best between participants with and without major dissociative disorders, were identified. FDS, DES and FDS-20 differentiate significantly between patients with and without major dissociative disorders. For all scales, there were significant differences between the diagnostic groups, with mean-scores decreasing continuously from the groups DID to DDNOS and TRAUMA. Between the groups non-TRAUMA and KG tendencies were found in the predicted direction. The optimal cutoff-scores to differentiate between participants with and without major dissociative disorders were 13 (FDS/FDS-20) and 15 (DES). Using these cutoff-scores, at least 90 % of the patients with major dissociative disorders could be identified correctly (sensitivity). The specifity of the scales was 0.89 to 0.90. Screening for major dissociative disorders

Does phasic trauma treatment make patients with dissociative identity disorder treatment more dissociative?

Science.gov (United States)

Brand, Bethany; Loewenstein, Richard J

2014-01-01

Proponents of the iatrogenic model of the etiology of dissociative identity disorder (DID) have expressed concern that treatment focused on direct engagement and interaction with dissociated self-states harms DID patients. However, empirical data have shown that this type of DID treatment is beneficial. Analyzing data from the prospective Treatment of Patients With Dissociative Disorders (TOP DD) Study, we test empirically whether DID treatment is associated with clinically adverse manifestations of dissociated self-states: acting so differently that one feels like different people, hearing voices, and dissociative amnesia. We show that, over the course of the study, there were significant decreases in feeling like different people and hearing voices. These results indicate that this form of DID treatment does not lead to symptomatic worsening in these dimensions, as predicted by the iatrogenic model. Indeed, treatment provided by TOP DD therapists reduced, rather than increased, the extent to which patients experienced manifestations of pathological dissociation. Because severe symptomatology and impairment are associated with DID, iatrogenic harm may come from depriving DID patients of treatment that targets DID symptomatology.

Pair interactions in polyelectrolyte-nanoparticle systems: Influence of dielectric inhomogeneities and the partial dissociation of polymers and nanoparticles

International Nuclear Information System (INIS)

Pryamitsyn, Victor; Ganesan, Venkat

2015-01-01

We study the effective pair interactions between two charged spherical particles in polyelectrolyte solutions using polymer self-consistent field theory. In a recent study [V. Pryamitsyn and V. Ganesan, Macromolecules 47, 6095 (2015)], we considered a model in which the particles possess fixed charge density, the polymers contain a prespecified amount of dissociated charges and, the dielectric constant of the solution was assumed to be homogeneous in space and independent of the polymer concentration. In this article, we present results extending our earlier model to study situations in which either or both the particle and the polymers possess partially dissociable groups. Additionally, we also consider the case when the dielectric constant of the solution depends on the local concentration of the polymers and when the particle’s dielectric constant is lower than that of the solvent. For each case, we quantify the polymer-mediated interactions between the particles as a function of the polymer concentrations and the degree of dissociation of the polymer and particles. Consistent with the results of our previous study, we observe that the polymer-mediated interparticle interactions consist of a short-range attraction and a long-range repulsion. The partial dissociablity of the polymer and particles was seen to have a strong influence on the strength of the repulsive portion of the interactions. Rendering the dielectric permittivity to be inhomogeneous has an even stronger effect on the repulsive interactions and results in changes to the qualitative nature of interactions in some parametric ranges

Dynamics and Thermodynamics of Transthyretin Association from Molecular Dynamics Simulations

Directory of Open Access Journals (Sweden)

Cedrix J. Dongmo Foumthuim

2018-01-01

Full Text Available Molecular dynamics simulations are used in this work to probe the structural stability and the dynamics of engineered mutants of transthyretin (TTR, i.e., the double mutant F87M/L110M (MT-TTR and the triple mutant F87M/L110M/S117E (3M-TTR, in relation to wild-type. Free energy analysis from end-point simulations and statistical effective energy functions are used to analyze trajectories, revealing that mutations do not have major impact on protein structure but rather on protein association, shifting the equilibria towards dissociated species. The result is confirmed by the analysis of 3M-TTR which shows dissociation within the first 10 ns of the simulation, indicating that contacts are lost at the dimer-dimer interface, whereas dimers (formed by monomers which pair to form two extended β-sheets appear fairly stable. Overall the simulations provide a detailed view of the dynamics and thermodynamics of wild-type and mutant transthyretins and a rationale of the observed effects.

Is the dissociative adult suggestible? A test of the trauma and fantasy models of dissociation.

Science.gov (United States)

Kluemper, Nicole S; Dalenberg, Constance

2014-01-01

Psychologists have long assumed a connection between traumatic experience and psychological dissociation. This hypothesis is referred to as the trauma model of dissociation. In the past decade, a series of papers have been published that question this traditional causal link, proposing an alternative fantasy model of dissociation. In the present research, the relationship among dissociation, suggestibility, and fantasy proneness was examined. Suggestibility was measured through the Gudjonsson Scale of Interrogative Suggestibility (GSS) as well as an autobiographically based version of this measure based on the events of September 11, 2001. Consistent with prior research and with the trauma model, dissociation correlated positively with trauma severity (r = .32, p suggestibility measure. Although some participants did become quite emotional during the procedure, the risk/benefit ratio was perceived by almost all participants to be positive, with more reactive individuals evaluating the procedure more positively. The results consistently support the trauma model of dissociation and fail to support the fantasy model of dissociation.

Estimation of acidity constants, ionic mobilities and charges of antimicrobial peptides by capillary electrophoresis

Czech Academy of Sciences Publication Activity Database

Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

2016-01-01

Roč. 37, 23/24 (2016), s. 3186-3195 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA15-01948S Institutional support: RVO:61388963 Keywords : acid dissociation constant * antimicrobial peptides * capillary electrophoresis * charge * mobility * Pka Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 2.744, year: 2016

Going full circle: phase-transition thermodynamics of ionic liquids.

Science.gov (United States)

Preiss, Ulrich; Verevkin, Sergey P; Koslowski, Thorsten; Krossing, Ingo

2011-05-27

We present the full enthalpic phase transition cycle for ionic liquids (ILs) as examples of non-classical salts. The cycle was closed for the lattice, solvation, dissociation, and vaporization enthalpies of 30 different ILs, relying on as much experimental data as was available. High-quality dissociation enthalpies were calculated at the G3 MP2 level. From the cycle, we could establish, for the first time, the lattice and solvation enthalpies of ILs with imidazolium ions. For vaporization, lattice, and dissociation enthalpies, we also developed new prediction methods in the course of our investigations. Here, as only single-ion values need to be calculated and the tedious optimization of an ion pair can be circumvented, the computational time is short. For the vaporization enthalpy, a very simple approach was found, using a surface term and the calculated enthalpic correction to the total gas-phase energy. For the lattice enthalpy, the most important constituent proved to be the calculated conductor-like screening model (COSMO) solvation enthalpy in the ideal electric conductor. A similar model was developed for the dissociation enthalpy. According to our assessment, the typical error of the lattice enthalpy would be 9.4 kJ mol(-1), which is less than half the deviation we get when using the (optimized) Kapustinskii equation or the recent volume-based thermodynamics (VBT) theory. In contrast, the non-optimized VBT formula gives lattice enthalpies 20 to 140 kJ mol(-1) lower than the ones we assessed in the cycle, because of the insufficient description of dispersive interactions. Our findings show that quantum-chemical calculations can greatly improve the VBT approaches, which were parameterized for simple, inorganic salts with ideally point-shaped charges. In conclusion, we suggest the term "augmented VBT", or "aVBT", to describe this kind of theoretical approach. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The thermodynamic-buffer enzymes.

Science.gov (United States)

Stucki, J W

1980-08-01

Oxidative phosphorylation operates at optimal efficiency if and only if the condition of conductance matching L33/L11 = square root 1-q2 is fulfilled. In this relation L11 is the phenomenological conductance of phosphorylation, L33 the phenomenological conductance of the load, i.e. the irreversible ATP-utilizing processes in the cell, and q the degree of coupling of oxidative phosphorylation driven by respiration. Since during short time intervals L11 and q are constant whereas L33 fluctuates in the cell, oxidative phosphorylation would only rarely operate at optimal efficiency due to violation of conductance matching. This paper demonstrates that the reversible ATP-utilizing reaction catalyzed by adenylate kinase can effectively compensate deviations from conductance matching in the presence of a fluctuating L33 and hence allows oxidative phosphorylation to operate at optimal efficiency in the cell. Since the adenylate kinase reaction was found to buffer a thermodynamic potential, i.e. the phosphate potential, this finding was generalized to the concept of thermodynamic buffering. The thermodynamic buffering ability of the adenylate kinase reaction was demonstrated by experiments with incubated rat-liver mitochondria. Considerations of changes introduced in the entropy production by the adenylate kinase reaction allowed to establish the theoretical framework for thermodynamic buffering. The ability of thermodynamic buffering to compensate deviations from conductance matching in the presence of fluctuating loads was demonstrated by computer simulations. The possibility of other reversible ATP-utilizing reactions, like the ones catalyzed by creatine kinase and arginine kinase, to contribute to thermodynamic buffering is discussed. Finally, the comparison of the theoretically calculated steady-stae cytosolic adenine nucleotide concentrations with experimental data from perfused livers demonstrated that in livers from fed rats conductance matching is fulfilled on a

Thermodynamics of complex formation of natural iron(III)porphyrins with neutral ligands

International Nuclear Information System (INIS)

Lebedeva, Nataliya Sh.; Yakubov, Sergey P.; Vyugin, Anatoly I.; Parfenyuk, Elena V.

2003-01-01

Calorimetric titrations in benzene and chloroform at 298.15 K have been performed to give the complexes stability constants and the thermodynamic parameters for the complex formation of nature iron(III)porphyrins with pyridine. Stoichimetry of the complexes formed has been determined. It has been found that the thermodynamic parameters obtained depend on nature of peripheral substituents of the porphyrins. The estimation of the influence of Cl - and Ac - ions on the processes studied has been carried out. Using thermodynamic analysis method, the crystallsolvates of nature iron(III)porphyrins with benzene have been studied. Stoichiometry, thermal and energetic stability of the π-π-complexes formed have been determined. The data obtained have been used to the estimate solvent effect on the thermodynamic parameters of axial coordination of pyridine on the iron(III)porphyrins in benzene

Diagram analysis of the Hubbard model: Stationarity property of the thermodynamic potential

International Nuclear Information System (INIS)

Moskalenko, V. A.; Dohotaru, L. A.; Cebotari, I. D.

2010-01-01

The diagram approach proposed many years ago for the strongly correlated Hubbard model is developed with the aim to analyze the thermodynamic potential properties. A new exact relation between renormalized quantities such as the thermodynamic potential, the one-particle propagator, and the correlation function is established. This relation contains an additional integration of the one-particle propagator with respect to an auxiliary constant. The vacuum skeleton diagrams constructed from the irreducible Green's functions and tunneling propagator lines are determined and a special functional is introduced. The properties of this functional are investigated and its relation to the thermodynamic potential is established. The stationarity property of this functional with respect to first-order variations of the correlation function is demonstrated; as a consequence, the stationarity property of the thermodynamic potential is proved.

Model, First-Principle Calculation of Ammonia Dissociation on Si(100 Surface. Importance of Proton Tunneling

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Marek Z. Zgierski

2003-06-01

Full Text Available Abstract: The dissociation of an ammonia molecule on a cluster of Si atoms simulating the 100 silicon crystal structure with two Si dimers has been investigated by means of the DFT and an approximate instanton methods. The model corresponds to the low coverage limit of the surface. Absolute rate constants of two different dissociation paths are evaluated together with deuterium isotope effects. It is demonstrated that, even at room temperatures, the process is dominated by tunneling and that dissociation to a silicon atom of the adjacent dimer, rather than a silicon within the same dimer, is the prevailing mechanism. This leads to creation of a metastable structure which will slowly decay through a two-step hydrogen atom migration towards the absolute minimum on the potential energy surface corresponding to the NH2 group and the hydrogen atom residing in the same dimer.

Direction-dependent force-induced dissociation dynamics of an entropic-driven lock-and-key assembly.

Science.gov (United States)

Chen, Yen-Fu; Chen, Hsuan-Yi; Sheng, Yu-Jane; Tsao, Heng-Kwong

2017-09-01

The unbinding dynamics of a nanosized sphere-and-cavity assembly under the pulling of constant force and constant loading rate is explored by dissipative particle dynamics simulations. The formation of this matched lock-and-key pair in a polymer solution is driven by the depletion attraction. The two-dimensional free energy landscape U(x,z) associated with this assembly is constructed. Our results indicate that the unbinding pathway along the orientation of the assembly is unfavorable due to the relatively high energy barrier compared to that along the tortuous minimum path whose energy barrier is not high. It is also found that the dissociation rate depends on the direction of the external force (θ) with respect to the assembly orientation. The presence of the force component perpendicular to the assembly orientation can reduce the bond lifetime significantly by driving the key particle to approach the minimum path. Moreover, the dissociation dynamics can be facilitated even by a pushing force compared to the spontaneous dissociation (without forces). To elucidate the effective pathway under pulling, the escaping position is analyzed and its mean direction with respect to the assembly orientation rises generally with increasing θ, revealing that the presence of the force component along the minimum pathway is helpful. The importance of the direction of the external pulling has been demonstrated in our simple system. Therefore, this effect should be considered in more complicated unbinding experiments.

Dynamics of contact line depinning during droplet evaporation based on thermodynamics.

Science.gov (United States)

Yu, Dong In; Kwak, Ho Jae; Doh, Seung Woo; Ahn, Ho Seon; Park, Hyun Sun; Kiyofumi, Moriyama; Kim, Moo Hwan

2015-02-17

For several decades, evaporation phenomena have been intensively investigated for a broad range of applications. However, the dynamics of contact line depinning during droplet evaporation has only been inductively inferred on the basis of experimental data and remains unclear. This study focuses on the dynamics of contact line depinning during droplet evaporation based on thermodynamics. Considering the decrease in the Gibbs free energy of a system with different evaporation modes, a theoretical model was developed to estimate the receding contact angle during contact line depinning as a function of surface conditions. Comparison of experimentally measured and theoretically modeled receding contact angles indicated that the dynamics of contact line depinning during droplet evaporation was caused by the most favorable thermodynamic process encountered during constant contact radius (CCR mode) and constant contact angle (CCA mode) evaporation to rapidly reach an equilibrium state during droplet evaporation.

Thermodynamic stability of elementary chemical reactions proceeding at finite rates revisited using Lyapunov function analysis

International Nuclear Information System (INIS)

Burande, Chandrakant S.; Bhalekar, Anil A.

2005-01-01

The thermodynamic stability of a few representative elementary chemical reactions proceeding at finite rates has been investigated using the recently proposed thermodynamic Lyapunov function and following the steps of Lyapunov's second method (also termed as the direct method) of stability of motion. The thermodynamic Lyapunov function; L s , used herein is the excess rate of entropy production in the thermodynamic perturbation space, which thereby inherits the dictates of the second law of thermodynamics. This Lyapunov function is not the same as the excess entropy rate that one encounters in thermodynamic (irreversible) literature. The model chemical conversions studied in this presentation are A+B→v x X and A+B↔ν x X. For the sake of simplicity, the thermal effects of chemical reactions have been considered as not adding to the perturbation as our main aim was to demonstrate how one should use systematically the proposed thermodynamic Lyapunov function following the steps of Lyapunov's second method of stability of motion. The domains of thermodynamic stability under the constantly acting small disturbances, thermodynamic asymptotic stability and thermodynamic instability in these model systems get established

Strong-field dissociation dynamics

International Nuclear Information System (INIS)

DiMauro, L.F.; Yang, Baorui.

1993-01-01

The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

Dissociation - a preliminary contextual model

Directory of Open Access Journals (Sweden)

C Krüger

2007-02-01

Full Text Available Background. The Diagnostic and Statistical Manual of Mental Disorders (DSM system has certain limitations when applied to two South African examples of dissociation, because it is descriptive (non-explanatory and focuses on intrapsychic (non-communal processes. Even the existing Western explanatory models of dissociation fail to accommodate fully the communal aspects of dissociation in our South African context. Objectives and methods. The aim was to explore an expanded perspective on dissociation that does not limit it to an intrapsychic phenomenon, but that accounts for the interrelatedness of individuals within their social context. Auto-ethnography was used. In this article a collective, socially orientated, contextual hermeneutic was applied to two local examples of dissociation. Three existing Western models were expanded along multicontextual, collective lines, for them to be more useful in the pluralistic South African context. Results. This preliminary contextual model of dissociation includes a person’s interpersonal, socio-cultural, and spiritual contexts, in addition to the intrapsychic context. Dissociation is considered to be a normal information-processing tool that maintains balanced, coherent selves-in-society, i.e. individuals connected to each other. In the South African context dissociation appears mostly as a normal phenomenon and seldom as a sign of mental illness. Dissociation is pivotal for the normal construction of individual and communal identities in the face of conflicting sets of information from various contexts. Dissociation may help individuals or communities to survive in a world of conflicting messages, where conflict is often interpersonal/cultural/societal in nature, rather than primarily intrapsychic. Conclusions. This model should be developed and evaluated further. Such evaluation would require suitable new local terminology.

Global functioning and disability in dissociative disorders.

Science.gov (United States)

Mueller-Pfeiffer, Christoph; Rufibach, Kaspar; Perron, Noelle; Wyss, Daniela; Kuenzler, Cornelia; Prezewowsky, Cornelia; Pitman, Roger K; Rufer, Michael

2012-12-30

Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV Axis I Disorders, Structured Clinical Interview for DSM-IV Dissociative Disorders, Global Assessment of Functioning Scale, and World Health Organization Disability Assessment Schedule-II. The association between subjects with a dissociative disorder (N=30) and functional impairment after accounting for non-dissociative axis I disorders was evaluated by linear regression models. We found a proportion of 18.8% dissociative disorders (dissociative amnesia=0%, dissociative fugue=0.6%, depersonalization disorder=4.4%, dissociative identity disorder=7.5%, dissociative disorder-not-otherwise-specified=6.3%) across treatment settings. Adjusted for other axis I disorders, subjects with a comorbid dissociative identity disorder or dissociative disorder-not-otherwise-specified had a median global assessment of functioning score that was 0.86 and 0.88 times, respectively, the score of subjects without a comorbid dissociative disorder. These findings support the hypothesis that complex dissociative disorders, i.e., dissociative identity disorder and dissociative disorder-not-otherwise-specified, contribute to functional impairment above and beyond the impact of co-existing non-dissociative axis I disorders, and that they qualify as "serious mental illness". Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Dissociation of acetaldehyde in intense laser field: Coulomb explosion or field-assisted dissociation?

Science.gov (United States)

Elshakre, Mohamed E.; Gao, Lirong; Tang, Xiaoping; Wang, Sufan; Shu, Yafei; Kong, Fanao

2003-09-01

Dissociation of acetaldehyde in moderate strong laser field of 1013-1014W/cm2 was investigated. Singly charged parent ion CH3CHO+ and fragmental ions CH3+, CHO+, C2H4+, O+, CH2CHO+, and H+ were produced by 800 nm laser of 100 fs pulse duration and recorded by time-of-flight mass spectrometer. The CH3+ fragment further dissociated to CH2+, CH+, and C+ ions at higher intensity. Ab initio calculated results show that the singly-, doubly-, and triply charged parent ions are stable. So, the dissociation mechanism was not due to Coulomb explosion of multicharged ion. A field-assisted dissociation (FAD) theory, which assumes that only one bond undergoes dissociation while the rest of the molecular geometry stays unchanged, was employed to treat the dissociation dynamics. Accordingly, the dressed potential energy surfaces of the ground state for the parent and the fragment ions were calculated. Corresponding quasiclassical trajectory calculations show that the bond ruptures take place in the order of C-C, C-O, and C-H, agreeing with the observation. The observed angular dependence and charge distribution of the product ions can also be interpreted by the FAD theory.

Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

International Nuclear Information System (INIS)

Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

2015-01-01

Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K 1 , log K 2 and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m 2 /g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K 1 , log K 2 ) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent

Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

Energy Technology Data Exchange (ETDEWEB)

Ma, Shu-Cui [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China); Wang, Zhi-Gang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Ji-Lin, E-mail: zjl@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Sun, De-Hui [Changchun Institute Technology, Changchun 130012 (China); Liu, Gui-Xia, E-mail: liuguixia22@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China)

2015-02-01

Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K{sub 1}, log K{sub 2} and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m{sup 2}/g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K{sub 1}, log K{sub 2}) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment.

Science.gov (United States)

Belli, Hasan

2014-08-16

Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative experiences scale can be used for screening dissociative symptoms and detecting dissociative disorders in patients with OCD. However, a history of neglect and abuse during childhood is linked to a risk factor in the pathogenesis of dissociative psychopathology in adults. The childhood trauma questionnaire-53 and childhood trauma questionnaire-40 can be used for this purpose. Clinicians should not fail to notice the hidden dissociative symptoms and childhood traumatic experiences in OCD cases with severe symptoms that are resistant to treatment. Symptom screening and diagnostic tools used for this purpose should be known. Knowing how to treat these pathologies in patients who are diagnosed with OCD can be crucial.

Uncovering the intrinsic relationship of electrocatalysis and molecular electrochemistry for dissociative electron transfer to polychloroethanes at silver cathode

International Nuclear Information System (INIS)

Huang, Binbin; Zhu, Yuanyuan; Li, Jing; Zeng, Guangming; Lei, Chao

2017-01-01

Highlights: • Thermodynamics of dissociative electron transfer to C–Cl bonds at Ag are studied. • The catalyzed dissociative electron transfer theory was proposed for the first time. • The adsorption of organic chlorides onto Ag plays a key role for dechlorination. • The catalytic property of Ag is ascribed to the lower of intrinsic barrier energy. • The relationship of electrocatalysis and molecular electrochemistry is indicated. - Abstract: The relationship between electrocatalysis and molecular electrochemistry for the reductive dechlorination of organic chlorides has been a central topic for decades. Herein, we try to reveal the catalytic property of silver electrode by investigating the thermodynamics of dissociative electron transfer (DET) to C–Cl bonds of polychloroethanes (PCAs) on both inert (GC) and catalytic (Ag) electrodes. By extending the “sticky” DET model reported by Savéant, we show that the catalyzed DET model can well describe the activation-driving force relationships for the electrocatalytic dechlorination on Ag, where in addition to the possible ion-dipole interations, the adsorption of chlorinated species onto Ag surface, which is found to play a fundamental role in the electrocatalysis process in this study, is introduced in the new developed DET model. In this work, we firstly report that the catalytic property of Ag electrode characterizing with drastically postive shift of reduction potential is ascribed to the lower of intrinsic barrier free energy, rather than the activation free energy, for the reductive dechlorination. Moreover, the intrinsic relationship of electrocatalysis and molecular electrochemistry is clearly indicated and quantitatively developed. These results may provide new insights in uncovering both the nature of catalytic property of Ag and the relationship of electrocatalysis and molecular electrochemistry for PCAs and other halocarbons.

Thermodynamics of the variable modified Chaplygin gas

Energy Technology Data Exchange (ETDEWEB)

Panigrahi, D. [Sree Chaitanya College, Habra 743268 (India); Chatterjee, S., E-mail: dibyendupanigrahi@yahoo.co.in, E-mail: chat_sujit1@yahoo.com [Relativity and Cosmology Research Centre, Jadavpur University, Kolkata – 700032 (India)

2016-05-01

A cosmological model with a new variant of Chaplygin gas obeying an equation of state (EoS), P = A ρ − B /ρ{sup α} where B = B {sub 0} a {sup n} is investigated in the context of its thermodynamical behaviour. Here B {sub 0} and n are constants and a is the scale factor. We show that the equation of state of this 'Variable Modified Chaplygin gas' (VMCG) can describe the current accelerated expansion of the universe. Following standard thermodynamical criteria we mainly discuss the classical thermodynamical stability of the model and find that the new parameter, n introduced in VMCG plays a crucial role in determining the stability considerations and should always be negative. We further observe that although the earlier model of Lu explains many of the current observational findings of different probes it fails the desirable tests of thermodynamical stability. We also note that for 0 n < our model points to a phantom type of expansion which, however, is found to be compatible with current SNe Ia observations and CMB anisotropy measurements. Further the third law of thermodynamics is obeyed in our case. Our model is very general in the sense that many of earlier works in this field may be obtained as a special case of our solution. An interesting point to note is that the model also apparently suggests a smooth transition from the big bang to the big rip in its whole evaluation process.

Ideal thermodynamic processes of oscillatory-flow regenerative engines will go to ideal stirling cycle?

Science.gov (United States)

Luo, Ercang

2012-06-01

This paper analyzes the thermodynamic cycle of oscillating-flow regenerative machines. Unlike the classical analysis of thermodynamic textbooks, the assumptions for pistons' movement limitations are not needed and only ideal flowing and heat transfer should be maintained in our present analysis. Under such simple assumptions, the meso-scale thermodynamic cycles of each gas parcel in typical locations of a regenerator are analyzed. It is observed that the gas parcels in the regenerator undergo Lorentz cycle in different temperature levels, whereas the locus of all gas parcels inside the regenerator is the Ericson-like thermodynamic cycle. Based on this new finding, the author argued that ideal oscillating-flow machines without heat transfer and flowing losses is not the Stirling cycle. However, this new thermodynamic cycle can still achieve the same efficiency of the Carnot heat engine and can be considered a new reversible thermodynamic cycle under two constant-temperature heat sinks.

Structural, Mechanical and Thermodynamic Properties under Pressure Effect of Rubidium Telluride: First Principle Calculations

Directory of Open Access Journals (Sweden)

Bidai K.

2017-06-01

Full Text Available First-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.

Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly.

Science.gov (United States)

Ram, Dushad; Ashoka, H G; Gowdappa, Basavnna

2015-01-01

Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly

OpenAIRE

Ram, Dushad; Ashoka, H. G; Gowdappa, Basavnna

2015-01-01

Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

Thermodynamic properties of diamond and wurtzite model fluids from computer simulation and thermodynamic perturbation theory

Science.gov (United States)

Zhou, S.; Solana, J. R.

2018-03-01

Monte Carlo NVT simulations have been performed to obtain the thermodynamic and structural properties and perturbation coefficients up to third order in the inverse temperature expansion of the Helmholtz free energy of fluids with potential models proposed in the literature for diamond and wurtzite lattices. These data are used to analyze performance of a coupling parameter series expansion (CPSE). The main findings are summarized as follows, (1) The CPSE provides accurate predictions of the first three coefficient in the inverse temperature expansion of Helmholtz free energy for the potential models considered and the thermodynamic properties of these fluids are predicted more accurately when the CPSE is truncated at second or third order. (2) The Barker-Henderson (BH) recipe is appropriate for determining the effective hard sphere diameter for strongly repulsive potential cores, but its performance worsens with increasing the softness of the potential core. (3) For some thermodynamic properties the first-order CPSE works better for the diamond potential, whose tail is dominated by repulsive interactions, than for the potential, whose tail is dominated by attractive interactions. However, the first-order CPSE provides unsatisfactory results for the excess internal energy and constant-volume excess heat capacity for the two potential models.

Reconsiderations of long debated subjects: uncertainty relations and Planck's constant

International Nuclear Information System (INIS)

Dumitru, S.

2005-01-01

Some earlier unresolved controversies about uncertainty relations and quantum measurements have persisted to this day. They originate in the shortcomings of the conventional interpretation of uncertainty relations. In this paper, we showed that those shortcomings exposed credible, unavoidable facts making it imperative that the conventional interpretation should be dropped. So, the primitive uncertainty relations appeared as being either figments or fluctuation formulae. Subsequently, we showed that for quantum microparticles the Planck constant h acted as an indicator of stochasticity, a role entirely similar to the one the Boltzmann constant k played in respect of the thermodynamic stochasticity of macroscopic systems. (author)

Determination of acid-base dissociation constants of azahelicenes by capillary zone electrophoresis

Czech Academy of Sciences Publication Activity Database

Ehala, Sille; Míšek, Jiří; Stará, Irena G.; Starý, Ivo; Kašička, Václav

2008-01-01

Roč. 31, č. 14 (2008), s. 2686-2693 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/06/1044; GA ČR GA203/08/1428; GA ČR GA203/07/1664; GA MŠk LC512 Institutional research plan: CEZ:AV0Z40550506 Keywords : acidity constant * azahelicenes * non-aqueous capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.746, year: 2008

Thermodynamics of the CSCl-H2O system at low temperatures

International Nuclear Information System (INIS)

Monnin, C.; Dubois, M.

1999-01-01

The interpretation of fluid-inclusion data requires knowledge of phase diagrams at low (subfreezing) temperatures. From the example of the CsCl-H 2 O system, we here investigate the possibility to build such diagrams from thermodynamic models of aqueous solutions parameterized at higher temperatures. Holmes and Mesmer (1983) have built a model for the thermodynamic properties of CsCl(aq) based on Pitzer's equation fit to thermodynamic data mainly at temperatures above 0 C along with a few freezing-point-depression data down to -8 C. We show how this model can be used along with the published water-ice equilibrium constant and thermodynamic data at 25 C for Cs + (aq), Cl - (aq) and CsCl(s), to predict with confidence the ice-liquid-vapor (ILV) and the salt-liquid-vapor (SLV) curves down to the eutectic temperature for the CsCl-H 2 O system. (orig.)

Symmetry, Optical Properties and Thermodynamics of Neptunium(V Complexes

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Linfeng Rao

2009-12-01

Full Text Available Recent results on the optical absorption and symmetry of the Np(V complexes with dicarboxylate and diamide ligands are reviewed. The importance of recognizing the “silent” feature of centrosymmetric Np(V species in analyzing the absorption spectra and calculating the thermodynamic constants of Np(V complexes is emphasized.

Dissociation and memory fragmentation in post-traumatic stress disorder: an evaluation of the dissociative encoding hypothesis.

Science.gov (United States)

Bedard-Gilligan, Michele; Zoellner, Lori A

2012-01-01

Several prominent theories of post-traumatic stress disorder (PTSD) posit that peritraumatic dissociation results in insufficient encoding of the trauma memory and that persistent dissociation prevents memory elaboration, resulting in memory fragmentation and PTSD. In this review we summarise the empirical literature on peritraumatic and trait dissociation and trauma narrative fragmentation as measured by meta-memory and rater/objective coding. Across 16 studies to date, the association between dissociation and fragmentation was most prominent when examining peritraumatic dissociation and patient's own ratings of memory fragmentation. This relationship did not hold when examining trait dissociation or rater-coded or computer-generated measures of fragmentation. Thus initial evidence points more towards a strong self-reported association between constructs that is not supported on more objective fragmentation coding. Measurement overlap, construct ambiguity, and exclusion of potential confounds may underlie lack of a strong association between dissociation and objective-rated fragmentation.

Multiphoton dissociation of polyatomic molecules

International Nuclear Information System (INIS)

Schulz, P.A.

1979-10-01

The dynamics of infrared multiphoton excitation and dissociation of SF 6 was investigated under collision free conditions by a crossed laser-molecular beam method. In order to understand the excitation mechanism and to elucidate the requirements of laser intensity and energy fluence, a series of experiments were carried out to measure the dissociation yield dependences on energy fluence, vibrational temperature of SF 6 , the pulse duration of the CO 2 laser and the frequency in both one and two laser experiments. Translational energy distributions of the SF 5 dissociation product measured by time of flight and angular distributions and the dissociation lifetime of excited SF 6 as inferred from the observation of secondary dissociation of SF 5 into SF 4 and F during the laser pulse suggest that the dynamics of dissociation of excited molecules is dominated by complete energy randomization and rapid intramolecular energy transfer on a nanosecond timescale, and can be adequately described by RRKM theory. An improved phenomenological model including the initial intensity dependent excitation, a rate equation describing the absorption and stimulated emission of single photons, and the unimolecular dissociation of excited molecules is constructed based on available experimental results. The model shows that the energy fluence of the laser determines the excitation of molecules in the quasi-continuum and the excess energy with which molecules dissociate after the laser pulse. The role played by the laser intensity in multiphoton dissociation is more significant than just that of overcoming the intensity dependent absorption in the lowest levels. 63 references

Black hole enthalpy and an entropy inequality for the thermodynamic volume

International Nuclear Information System (INIS)

Cvetic, M.; Gibbons, G. W.; Kubiznak, D.; Pope, C. N.

2011-01-01

In a theory where the cosmological constant Λ or the gauge coupling constant g arises as the vacuum expectation value, its variation should be included in the first law of thermodynamics for black holes. This becomes dE=TdS+Ω i dJ i +Φ α dQ α +ΘdΛ, where E is now the enthalpy of the spacetime, and Θ, the thermodynamic conjugate of Λ, is proportional to an effective volume V=-(16πΘ/D-2)''inside the event horizon.'' Here we calculate Θ and V for a wide variety of D-dimensional charged rotating asymptotically anti-de Sitter (AdS) black hole spacetimes, using the first law or the Smarr relation. We compare our expressions with those obtained by implementing a suggestion of Kastor, Ray, and Traschen, involving Komar integrals and Killing potentials, which we construct from conformal Killing-Yano tensors. We conjecture that the volume V and the horizon area A satisfy the inequality R≡ ((D-1)V/A D-2 ) 1/(D-1) (A D-2 /A) 1/(D-2) ≥1, where A D-2 is the volume of the unit (D-2) sphere, and we show that this is obeyed for a wide variety of black holes, and saturated for Schwarzschild-AdS. Intriguingly, this inequality is the ''inverse'' of the isoperimetric inequality for a volume V in Euclidean (D-1) space bounded by a surface of area A, for which R≤1. Our conjectured reverse isoperimetric inequality can be interpreted as the statement that the entropy inside a horizon of a given ''volume''V is maximized for Schwarzschild-AdS. The thermodynamic definition of V requires a cosmological constant (or gauge coupling constant). However, except in seven dimensions, a smooth limit exists where Λ or g goes to zero, providing a definition of V even for asymptotically flat black holes.

Thermodynamics of event horizons in (2+1)-dimensional gravity

International Nuclear Information System (INIS)

Reznik, B.

1992-01-01

Although gravity in 2+1 dimensions is very different in nature from gravity in 3+1 dimensions, it is shown that the laws of thermodynamics for event horizons can be manifested also for (2+1)-dimensional gravity. The validity of the classical laws of horizon mechanics is verified in general and exemplified for the (2+1)-dimensional analogues of Reissner-Nordstroem and Schwarzschild--de Sitter spacetimes. We find that the entropy is given by 1/4L, where L is the length of the horizon. A consequence of having consistent thermodynamics is that the second law fixes the sign of Newton's constant to be positive

Structural and thermodynamic aspects of the dissociation of cyclopentadienyl rings from homoleptic cyclopentadienyl early transition metal, cerium, and thorium derivatives

International Nuclear Information System (INIS)

Peng Bin; Cheng Feng; Li Qianshu; Xie Yaoming; King, R. Bruce; Schaefer, Henry F.

2011-01-01

Graphical abstract: Density functional theory indicates that for Cp 4 M the S 4 structures are saddle points and the minima have C 1 symmetry with all η 5 -Cp rings for M = Ce and Th, three η 5 -Cp rings and one η 5 -Cp ring for M = Zr, and two η 5 -Cp rings and two η 5 -Cp rings for M = Ti and Hf. The dissociation energies for Cp 4 M → Cp 3 M + Cp · increase in the sequence Ti 3h structures with all η 5 -Cp rings are genuine minima for most of the Cp 3 M compounds except for Cp 3 Ti, which has a Cs symmetry minimum with two η 5 -Cp rings and one η 2 -Cp ring. The dissociation energies for Cp 3 M → Cp 2 M + Cp · increase in the sequence V 4 M the S 4 structures are saddle points. → The minima for Cp 4 M have all η 5 -Cp rings for M = Ce and Th, three η 5 -Cp rings and one η 1 -Cp ring for M = Zr, and two η 5 -Cp rings and two η 5 -Cp rings for M = Ti and Hf. → The dissociation energies for Cp 4 M → Cp 3 M + Cp · increase in the sequence Ti 3h structures with all η 5 -Cp rings are genuine minima for all of the Cp 3 M compounds except for Cp 3 Ti. → The dissociation energies for Cp 3 M → Cp 2 M + Cp · increase in the sequence V 4 M (M = Ti, Zr, Ce, Hf, Th), Cp 3 M (M = Sc, Y, most lanthanides, Ti, Zr, Hf, Th), and Cp 2 M (M = Ti, V). Density functional theory shows that the Cp 4 M structures with unusual S 4 symmetry are saddle points for the d-block metals Ti, Zr, Hf but genuine minima for the f-block metals Ce and Th. The true equilibrium Cp 4 M geometries have C 1 symmetry with two η 5 -Cp rings and two η 1 -Cp rings for M = Ti and Hf but three η 5 -Cp rings and one η 1 -Cp ring for M = Zr. The dissociation energies for Cp 4 M → Cp 3 M + Cp · are substantial and in the order Ti 3h structures with all η 5 -Cp rings are genuine minima for most of the Cp 3 M compounds except for Cp 3 Ti, which has a C s symmetry minimum with two η 5 -Cp rings and one η 2 -Cp ring, and Cp 3 V, which has two η 5 -Cp rings and one η 1 -Cp ring

Enthalpies of Dissolution of Crystalline Naproxen Sodium in Water and Potassium Hydroxide Aqueous Solutions at 298 K

Science.gov (United States)

Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Volkov, A. V.; Skvortsov, I. A.

2018-03-01

The enthalpies of dissolution of crystalline naproxen sodium in water and aqueous solutions of KOH at 298.15 K are measured by direct calorimetric means in a wide range of concentrations. The acid-base properties of naproxen sodium at ionic strength I 0 and I = 0.1 (KNO3) and a temperature of 298.15 K are studied by spectrophotometric means. The concentration and thermodynamic dissociation constants are determined. The standard enthalpies of the formation of naproxen sodium and the products of its dissociation in aqueous solution are calculated.

Thermodynamics of ion exchange equilibrium for some uni ...

African Journals Online (AJOL)

The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Indion FF-IP. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as ...

Dissociation behavior of Np(IV) from humic acid colloid

Energy Technology Data Exchange (ETDEWEB)

Iijima, K.; Tobitsuka, S. [Japan Nuclear Cycle Development Institute, 4-33 Muramatsu, Tokai, Naka-gun, Ibaraki 319-1194 (Japan); Kohara, Y. [Inspection Development Corporation, 4-33, Muramatsu, Tokai, Nakagun, Ibaraki 319-1112 (Japan)

2005-07-01

Full text of publication follows: Dissociation behavior of Np(IV) from humic colloid, which was prepared with purified Aldrich humic acid (PAHA) was investigated. The complexation experiments were carried out in 0.1 M NaClO{sub 4} - 0.05 M Na{sub 2}S{sub 2}O{sub 4} solution at pH 8 with PAHA concentration between 0 and 500 mg L-1 under anaerobic condition. Np-237 was added as Np(V) solution so that its concentration becomes 1.1 x 10-5 mol L-1. After shaking from 1 to 156 days, aliquots of experimental solution were filtered through the membranes with 50, 10 and 3 kD of MWCO to obtain the size distribution of colloid, followed by adding the filtrate into the 6 M HCl for dissociation. At the end of experiments for 596 days, 0.1 M NaHCO{sub 3} was used for dissociation solution. The concentration of Np released into this solution was evaluated by measuring a activity of Np-237. The concentration of Np becomes constant by 112 days. Since Eh of the solution has been kept between -300 and -100 mV vs. SHE during experimental duration, Np is presumed to be reduced into tetravalent. In the case of higher PAHA concentration than 50 mg L{sup -1}, the Np concentration is close to that of initially added Np. Since the size of the dissolved species of Np during complexation experiments varies from 3 to 50 kD, the Np is sorbed on humic acid colloid. In the dissociation experiments, the Np dissociated by 6 M HCl decreases with increasing complexation time and PAHA concentration. After 156 days complexation with 500 mg L{sup -1} of PAHA, 35% of Np can be dissociated from the colloid. Such a tendency, however, is not observed in case of the lowest PAHA concentration, 5 mg L{sup -1}. After 596 days complexation, the dissociation experiments were carried out by adding 0.1 M NaHCO{sub 3} solution to avoid the precipitation which might hinder the dissociation of Np in the aforementioned experiments with HCl. As a result, 50% of Np is dissociated in the presence of 50 and 100 mg L-1 of

Hyperglycemia associated dissociative fugue (organic dissociative disorder in an elderly

Directory of Open Access Journals (Sweden)

Dushad Ram

2015-01-01

Full Text Available Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

convergent methods for calculating thermodynamic Green functions

OpenAIRE

Bowen, S. P.; Williams, C. D.; Mancini, J. D.

1984-01-01

A convergent method of approximating thermodynamic Green functions is outlined briefly. The method constructs a sequence of approximants which converges independently of the strength of the Hamiltonian's coupling constants. Two new concepts associated with the approximants are introduced: the resolving power of the approximation, and conditional creation (annihilation) operators. These ideas are illustrated on an exactly soluble model and a numerical example. A convergent expression for the s...

Dissociative disorders in DSM-5.

Science.gov (United States)

Spiegel, David; Lewis-Fernández, Roberto; Lanius, Ruth; Vermetten, Eric; Simeon, Daphne; Friedman, Matthew

2013-01-01

The rationale, research literature, and proposed changes to the dissociative disorders and conversion disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are presented. Dissociative identity disorder will include reference to possession as well as identity fragmentation, to make the disorder more applicable to culturally diverse situations. Dissociative amnesia will include dissociative fugue as a subtype, since fugue is a rare disorder that always involves amnesia but does not always include confused wandering or loss of personality identity. Depersonalization disorder will include derealization as well, since the two often co-occur. A dissociative subtype of posttraumatic stress disorder (PTSD), defined by the presence of depersonalization or derealization in addition to other PTSD symptoms, is being recommended, based upon new epidemiological and neuroimaging evidence linking it to an early life history of adversity and a combination of frontal activation and limbic inhibition. Conversion disorder (functional neurological symptom disorder) will likely remain with the somatic symptom disorders, despite considerable dissociative comorbidity.

THE INFLUENCE OF THE SOLVENT ON THE THERMODYNAMICS OF ION ASSOCIATION

Directory of Open Access Journals (Sweden)

Vitalii Chumak

2011-03-01

Full Text Available Abstract. Some approaches which allow to divide thermodynamic functions of the ion associationprocess in two components have been developed. The first component belongs to the process, the second oneis caused by the temperature dependence of the dielectric permittivity of the solvent. The theory is confirmedby numerous examples of the ion association process of different electrolytes in the binary mixed solvents.Keywords: covalent part of the constant of ionic association, electrostatic part of the constant of ionicassociation, enthalpy of the chemical equilibria in solution, enthropy of the chemical equilibria in solution,ionic association, ionic equilibrias, the equilibrium constant.

Predictive thermodynamic models for liquid--liquid extraction of single, binary and ternary lanthanides and actinides

International Nuclear Information System (INIS)

Hoh, Y.C.

1977-03-01

Chemically based thermodynamic models to predict the distribution coefficients and the separation factors for the liquid--liquid extraction of lanthanides-organophosphorus compounds were developed by assuming that the quotient of the activity coefficients of each species varies slightly with its concentrations, by using aqueous lanthanide or actinide complexes stoichiometric stability constants expressed as its degrees of formation, by making use of the extraction mechanism and the equilibrium constant for the extraction reaction. For a single component system, the thermodynamic model equations which predict the distribution coefficients, are dependent on the free organic concentration, the equilibrated ligand and hydrogen ion concentrations, the degree of formation, and on the extraction mechanism. For a binary component system, the thermodynamic model equation which predicts the separation factors is the same for all cases. This model equation is dependent on the degrees of formation of each species in their binary system and can be used in a ternary component system to predict the separation factors for the solutes relative to each other

Parametric analysis of the thermodynamic properties for a medium with strong interaction between particles

International Nuclear Information System (INIS)

Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.

1996-01-01

Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior

Thermodynamic analysis of the two-phase ejector air-conditioning system for buses

International Nuclear Information System (INIS)

Ünal, Şaban; Yilmaz, Tuncay

2015-01-01

Air-conditioning compressors of the buses are usually operated with the power taken from the engine of the buses. Therefore, an improvement in the air-conditioning system will reduce the fuel consumption of the buses. The improvement in the coefficient of performance (COP) of the air-conditioning system can be provided by using the two-phase ejector as an expansion valve in the air-conditioning system. In this study, the thermodynamic analysis of bus air-conditioning system enhanced with a two-phase ejector and two evaporators is performed. Thermodynamic analysis is made assuming that the mixing process in ejector occurs at constant cross-sectional area and constant pressure. The increase rate in the COP with respect to conventional system is analyzed in terms of the subcooling, condenser and evaporator temperatures. The analysis shows that COP improvement of the system by using the two phase ejector as an expansion device is 15% depending on design parameters of the existing bus air-conditioning system. - Highlights: • Thermodynamic analysis of the two-phase ejector refrigeration system. • Analysis of the COP increase rate of bus air-conditioning system. • Analysis of the entrainment ratio of the two-phase ejector refrigeration system

Catalytic methanol dissociation

International Nuclear Information System (INIS)

Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

1998-01-01

Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

Dynamics and thermodynamics of polymer glasses.

Science.gov (United States)

Cangialosi, D

2014-04-16

The fate of matter when decreasing the temperature at constant pressure is that of passing from gas to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within the wide variety of glass formers, an important sub-class is represented by glass forming polymers. The presence of chain connectivity and, in some cases, conformational disorder are unfavourable factors from the point of view of crystallization. Furthermore, many of them, such as amorphous thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review, the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with particular emphasis on those topics currently the subject of debate. In particular, the following aspects will be reviewed in the present work: (i) the connection between the pronounced slowing down of glassy dynamics on cooling towards the glass transition temperature (Tg) and the thermodynamics; and, (ii) the fate of the dynamics and thermodynamics below Tg. Both aspects are reviewed in light of the possible presence of a singularity at a finite temperature with diverging relaxation time and zero configurational entropy. In this context, the specificity of glass-forming polymers is emphasized.

Predicting the Cosmological Constant from the Causal Entropic Principle

Energy Technology Data Exchange (ETDEWEB)

Bousso, Raphael; Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

2007-05-01

We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach-weighting by the number of"observers per baryon" -- is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

Predicting the Cosmological Constant from the CausalEntropic Principle

Energy Technology Data Exchange (ETDEWEB)

Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

2007-02-20

We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, it asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach--weighting by the number of ''observers per baryon''--is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

Thermodynamics of Lovelock-Lifshitz black branes

International Nuclear Information System (INIS)

Dehghani, M. H.; Mann, R. B.

2010-01-01

We investigate the thermodynamics of Lovelock-Lifshitz black branes. We begin by introducing the finite action of third order Lovelock gravity in the presence of a massive vector field for a flat boundary, and use it to compute the energy density of these black branes. Using the field equations, we find a conserved quantity along the r coordinate that relates the metric parameters at the horizon and at infinity. Remarkably, though the subleading large-r behavior of Lovelock-Lifshitz black branes differs substantively from their Einsteinian Lifshitz counterparts, we find that the relationship between the energy density, temperature, and entropy density is unchanged from Einsteinian gravity. Using the first law of thermodynamics to obtain the relationship between entropy and temperature, we find that it too is the same as the Einsteinian case, apart from a constant of integration that depends on the Lovelock coefficients.

Geometrical thermodynamics and P-V criticality of the black holes with power-law Maxwell field

Energy Technology Data Exchange (ETDEWEB)

Hendi, S.H.; Panah, B.E. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Panahiyan, S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Talezadeh, M.S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)

2017-02-15

We study the thermodynamical structure of Einstein black holes in the presence of power Maxwell invariant nonlinear electrodynamics for two different cases. The behavior of temperature and conditions regarding the stability of these black holes are investigated. Since the language of geometry is an effective method in general relativity, we concentrate on the geometrical thermodynamics to build a phase space for studying thermodynamical properties of these black holes. In addition, taking into account the denominator of the heat capacity, we use the proportionality between cosmological constant and thermodynamical pressure to extract the critical values for these black holes. Besides, the effects of the variation of different parameters on the thermodynamical structure of these black holes are investigated. Furthermore, some thermodynamical properties such as the volume expansion coefficient, speed of sound, and isothermal compressibility coefficient are calculated and some remarks regarding these quantities are given. (orig.)

Geometrical thermodynamics and P-V criticality of the black holes with power-law Maxwell field

International Nuclear Information System (INIS)

Hendi, S.H.; Panah, B.E.; Panahiyan, S.; Talezadeh, M.S.

2017-01-01

We study the thermodynamical structure of Einstein black holes in the presence of power Maxwell invariant nonlinear electrodynamics for two different cases. The behavior of temperature and conditions regarding the stability of these black holes are investigated. Since the language of geometry is an effective method in general relativity, we concentrate on the geometrical thermodynamics to build a phase space for studying thermodynamical properties of these black holes. In addition, taking into account the denominator of the heat capacity, we use the proportionality between cosmological constant and thermodynamical pressure to extract the critical values for these black holes. Besides, the effects of the variation of different parameters on the thermodynamical structure of these black holes are investigated. Furthermore, some thermodynamical properties such as the volume expansion coefficient, speed of sound, and isothermal compressibility coefficient are calculated and some remarks regarding these quantities are given. (orig.)

Modeling the Thermosphere as a Driven-Dissipative Thermodynamic System

Science.gov (United States)

2013-03-01

8 Figure 2: Illustration of the geocentric solar magnetospheric coordinate system............15 Figure 3: Diagram of the...to test new methods of modeling the thermospheric environment. Thermosphere as a Driven-Dissipative Thermodynamic System One approach for modeling... approach uses empirical coupling and relaxation constants to model the 4 input of energy to the thermosphere from the solar wind during

Thermodynamics of Binary Mixed Crystals in the Sub-quasi-chemical/Debye Approximation

Science.gov (United States)

van der Kemp, W. J. M.; Verdonk, M. L.

1995-03-01

A new statistical model for the description of the thermodynamic properties of binary mixed crystals is discussed. The model is based on an asymmetrical analogue of the quasi-chemical approximation and the Debye model of a solid. With two interchange -energy parameters and two interchange-Debye-temperature parameters, all important thermodynamic functions, at constant volume, of the binary mixed crystal can be calculated as a function of temperature and composition. The binary system {( 1 - x)Nai + xKI}(s) is used for illustration of the model.

Dissociative symptoms and neuroendocrine dysregulation in depression.

Science.gov (United States)

Bob, Petr; Fedor-Freybergh, Peter; Jasova, Denisa; Bizik, Gustav; Susta, Marek; Pavlat, Josef; Zima, Tomas; Benakova, Hana; Raboch, Jiri

2008-10-01

Dissociative symptoms are traditionally attributed to psychological stressors that produce dissociated memories related to stressful life events. Dissociative disorders and dissociative symptoms including psychogenic amnesia, fugue, dissociative identity-disorder, depersonalization, derealization and other symptoms or syndromes have been reported as an epidemic psychiatric condition that may be coexistent with various psychiatric diagnoses such as depression, schizophrenia, borderline personality disorder or anxiety disorders. According to recent findings also the somatic components of dissociation may occur and influence brain, autonomic and neuroendocrine functions. At this time there are only few studies examining neuroendocrine response related to dissociative symptoms that suggest significant dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. The aim of the present study is to perform examination of HPA axis functioning indexed by basal cortisol and prolactin and test their relationship to psychic and somatoform dissociative symptoms. Basal cortisol and prolactin and psychic and somatoform dissociative symptoms were assessed in 40 consecutive inpatients with diagnosis of unipolar depression mean age 43.37 (SD=12.21). The results show that prolactin and cortisol as indices of HPA axis functioning manifest significant relationship to dissociative symptoms. Main results represent highly significant correlations obtained by simple regression between psychic dissociative symptoms (DES) and serum prolactin (R=0.55, p=0.00027), and between somatoform dissociation (SDQ-20) and serum cortisol (R=-0.38, p=0.015). These results indicate relationship between HPA-axis reactivity and dissociative symptoms in unipolar depressive patients that could reflect passive coping behavior and disengagement.

Estimation of stability constants of metal monoacidocomplexes in aqueous solutions (1:2) of electrolytes

International Nuclear Information System (INIS)

Ryazanov, M.A.

1992-01-01

On the basis of the concept of the model of isoactive solutions it is shown that osmosis pressure of aqueous solutions (1:2) of electrolytes is well described by the Van-der-Vaals model for ideal associated gas. Stabilisty constants were calculated using osmosis mole parts of interacting particles as a concentrational scale. Stability constants in the scale of osmosis mole parts are equal to thermodynamic contstants, rated for an infinitely diluted solution

First-principles study on electronic, optic, elastic, dynamic and thermodynamic properties of RbH compound

Directory of Open Access Journals (Sweden)

Gulebaglan Sinem Erden

2015-01-01

Full Text Available We performed first-principles calculations to obtain the electronic, optical, elastic, lattice-dynamical and thermodynamic properties of RbH compound with rock salt structure. The ground-state properties, i.e., the lattice constant and the band gap were investigated using a plane wave pseudopotential method within density functional theory. The calculated lattice constant, bulk modulus, energy band gap and elastic constants are reported and compared with previous theoretical and experimental results. Our calculated results and the previous results which are obtained from literature are in a good agreement. Moreover, real and imaginary parts of complex dielectric function, reflectivity spectrum, absorption, extinction coefficient and loss function as a function of photon energy and refractive index with respect to photon wavelength were calculated. In addition, temperature dependent thermodynamic properties such as Helmholtz free energy, internal energy, entropy and specific heat have been studied.

Dissociative symptomatology in cancer patients

Science.gov (United States)

Civilotti, Cristina; Castelli, Lorys; Binaschi, Luca; Cussino, Martina; Tesio, Valentina; Di Fini, Giulia; Veglia, Fabio; Torta, Riccardo

2015-01-01

Introduction: The utilization of the post-traumatic stress disorder (PTSD) diagnostic spectrum is currently being debated to categorize psychological adjustment in cancer patients. The aims of this study were to: (1) evaluate the presence of cancer-related traumatic dissociative symptomatology in a sample of cancer patients; (2) examine the correlation of cancer-related dissociation and sociodemographic and medical variables, anxiety, depression, and post-traumatic stress symptomatology; (3) investigate the predictors of cancer-related dissociation. Methods: Ninety-two mixed cancer patients (mean age: 58.94, ds = 10.13) recruited from two hospitals in northern Italy were administered a questionnaire on sociodemographic and medical characteristics, the Karnofsky Scale to measure the level of patient activity and medical care requirements, the Hospital Anxiety and Depression Scale (HADS) to evaluate the presence of anxiety and depression, the Impact of Event Scale Revised (IES-R) to assess the severity of intrusion, avoidance, and hypervigilance, and the Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to quantify the traumatic dissociative symptomatology. Results: 31.5% of participants report a PDEQ score above the cutoff. The results indicated that dissociative symptomatology was positively correlated with HADS scores (HADS-Anxiety: r = 0.476, p dissociative symptomatology. The results converged on a three predictor model revealing that IES-R-Intrusion, IES-R-Avoidance, and IES-R-Hyperarousal accounted for 53.9% of the explained variance. Conclusion: These findings allow us to hypothesize a specific psychological reaction which may be ascribed to the traumatic spectrum within the context of cancer, emphasizing the close relationship between the origin of dissociative constituents which, according to the scientific literature, compose the traumatic experience. Our results have implications for understanding dissociative symptomatology in a cancer

Hydrate dissociation conditions for gas mixtures containing carbon dioxide, hydrogen, hydrogen sulfide, nitrogen, and hydrocarbons using SAFT

International Nuclear Information System (INIS)

Li Xiaosen; Wu Huijie; Li Yigui; Feng Ziping; Tang Liangguang; Fan Shuanshi

2007-01-01

A new method, a molecular thermodynamic model based on statistical mechanics, is employed to predict the hydrate dissociation conditions for binary gas mixtures with carbon dioxide, hydrogen, hydrogen sulfide, nitrogen, and hydrocarbons in the presence of aqueous solutions. The statistical associating fluid theory (SAFT) equation of state is employed to characterize the vapor and liquid phases and the statistical model of van der Waals and Platteeuw for the hydrate phase. The predictions of the proposed model were found to be in satisfactory to excellent agreement with the experimental data

Experimentally-induced dissociation impairs visual memory.

Science.gov (United States)

Brewin, Chris R; Mersaditabari, Niloufar

2013-12-01

Dissociation is a phenomenon common in a number of psychological disorders and has been frequently suggested to impair memory for traumatic events. In this study we explored the effects of dissociation on visual memory. A dissociative state was induced experimentally using a mirror-gazing task and its short-term effects on memory performance were investigated. Sixty healthy individuals took part in the experiment. Induced dissociation impaired visual memory performance relative to a control condition; however, the degree of dissociation was not associated with lower memory scores in the experimental group. The results have theoretical and practical implications for individuals who experience frequent dissociative states such as patients with posttraumatic stress disorder (PTSD). Copyright © 2013 Elsevier Inc. All rights reserved.

Speech-Language Dissociations, Distractibility, and Childhood Stuttering

Science.gov (United States)

Conture, Edward G.; Walden, Tedra A.; Lambert, Warren E.

2015-01-01

Purpose This study investigated the relation among speech-language dissociations, attentional distractibility, and childhood stuttering. Method Participants were 82 preschool-age children who stutter (CWS) and 120 who do not stutter (CWNS). Correlation-based statistics (Bates, Appelbaum, Salcedo, Saygin, & Pizzamiglio, 2003) identified dissociations across 5 norm-based speech-language subtests. The Behavioral Style Questionnaire Distractibility subscale measured attentional distractibility. Analyses addressed (a) between-groups differences in the number of children exhibiting speech-language dissociations; (b) between-groups distractibility differences; (c) the relation between distractibility and speech-language dissociations; and (d) whether interactions between distractibility and dissociations predicted the frequency of total, stuttered, and nonstuttered disfluencies. Results More preschool-age CWS exhibited speech-language dissociations compared with CWNS, and more boys exhibited dissociations compared with girls. In addition, male CWS were less distractible than female CWS and female CWNS. For CWS, but not CWNS, less distractibility (i.e., greater attention) was associated with more speech-language dissociations. Last, interactions between distractibility and dissociations did not predict speech disfluencies in CWS or CWNS. Conclusions The present findings suggest that for preschool-age CWS, attentional processes are associated with speech-language dissociations. Future investigations are warranted to better understand the directionality of effect of this association (e.g., inefficient attentional processes → speech-language dissociations vs. inefficient attentional processes ← speech-language dissociations). PMID:26126203

Objective documentation of child abuse and dissociation in 12 murderers with dissociative identity disorder.

Science.gov (United States)

Lewis, D O; Yeager, C A; Swica, Y; Pincus, J H; Lewis, M

1997-12-01

The skepticism regarding the existence of dissociative identity disorder as well as the abuse that engenders it persists for lack of objective documentation. This is doubly so for the disorder in murderers because of issues of suspected malingering. This article presents objective verification of both dissociative symptoms and severe abuse during childhood in a series of adult murderers with dissociative identity disorder. This study consisted of a review of the clinical records of 11 men and one woman with DSM-IV-defined dissociative identity disorder who had committed murder. Data were gathered from medical, psychiatric, social service, school, military, and prison records and from records of interviews with subjects' family members and others. Handwriting samples were also examined. Data were analyzed qualitatively. Signs and symptoms of dissociative identity disorder in childhood and adulthood were corroborated independently and from several sources in all 12 cases; objective evidence of severe abuse was obtained in 11 cases. The subjects had amnesia for most of the abuse and underreported it. Marked changes in writing style and/or signatures were documented in 10 cases. This study establishes, once and for all, the linkage between early severe abuse and dissociative identity disorder. Further, the data demonstrate that the disorder can be distinguished from malingering and from other disorders. The study shows that it is possible, with great effort, to obtain objective evidence of both the symptoms of dissociative identity disorder and the abuse that engenders it.

Dissociative Part-Dependent Resting-State Activity in Dissociative Identity Disorder : A Controlled fMRI Perfusion Study

NARCIS (Netherlands)

Schlumpf, Yolanda R.; Reinders, Antje A. T. S.; Nijenhuis, Ellert R. S.; Luechinger, Roger; van Osch, Matthias J. P.; Jaencke, Lutz

2014-01-01

Background: In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part'' (EP) and the "Apparently Normal Part'' (ANP), have

The elastic properties, generalized stacking fault energy and dissociated dislocations in MgB2 under different pressure

KAUST Repository

Feng, Huifang

2013-05-31

The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.

Thermodynamic state ensemble models of cis-regulation.

Directory of Open Access Journals (Sweden)

Marc S Sherman

Full Text Available A major goal in computational biology is to develop models that accurately predict a gene's expression from its surrounding regulatory DNA. Here we present one class of such models, thermodynamic state ensemble models. We describe the biochemical derivation of the thermodynamic framework in simple terms, and lay out the mathematical components that comprise each model. These components include (1 the possible states of a promoter, where a state is defined as a particular arrangement of transcription factors bound to a DNA promoter, (2 the binding constants that describe the affinity of the protein-protein and protein-DNA interactions that occur in each state, and (3 whether each state is capable of transcribing. Using these components, we demonstrate how to compute a cis-regulatory function that encodes the probability of a promoter being active. Our intention is to provide enough detail so that readers with little background in thermodynamics can compose their own cis-regulatory functions. To facilitate this goal, we also describe a matrix form of the model that can be easily coded in any programming language. This formalism has great flexibility, which we show by illustrating how phenomena such as competition between transcription factors and cooperativity are readily incorporated into these models. Using this framework, we also demonstrate that Michaelis-like functions, another class of cis-regulatory models, are a subset of the thermodynamic framework with specific assumptions. By recasting Michaelis-like functions as thermodynamic functions, we emphasize the relationship between these models and delineate the specific circumstances representable by each approach. Application of thermodynamic state ensemble models is likely to be an important tool in unraveling the physical basis of combinatorial cis-regulation and in generating formalisms that accurately predict gene expression from DNA sequence.

Thermodynamic properties of donor-acceptor complexes of tertiary amine with aryl ketones in hexane medium

Energy Technology Data Exchange (ETDEWEB)

Kumar, R. [Department of Physics, The New College, Chennai 600 014 (India); Jayakumar, S. [Department of Physics, R.K.M. Vivekananda College, Chennai 600 004 (India); Kannappan, V., E-mail: vkannappan@hotmail.com [Department of Chemistry, Presidency College, Chennai 600 005 (India)

2012-05-20

Highlights: Black-Right-Pointing-Pointer Ultrasonic scan is carried out on ternary systems of aromatic tertiary amine and three aryl ketones. Black-Right-Pointing-Pointer Formation of CT complexes is found between tertiary amine with aryl ketones. Black-Right-Pointing-Pointer Stability constant values are computed by ultrasonic and spectral methods are compared. Black-Right-Pointing-Pointer The trend in the 'K' suggests that substituents in ketones influence the stabilities of these complexes. Black-Right-Pointing-Pointer The thermodynamic parameters suggest CT interaction is exothermic and the complexes are thermodynamically stable. - The thermodynamic stability of complexes formed between N,N-dimethylaniline (DMANI) and three ketones, namely, acetophenone (ACP), 4-chloroactophenone (ClACP) and 4-methylacetophenone (MACP) in n-hexane is extensively investigated by spectral and ultrasonic methods. The ultrasound scan was carried out in the temperature range 208.15-313.15 K and at atmospheric pressure on solutions containing equimolar concentrations of components ranging from 0.025 to 0.2 M. The existence of solute-solute interactions has also been confirmed through electronic absorption spectra analyzed with Benesi-Hildebrand theory at 303.15 K. The stability constants of the donor-acceptor complexes determined both by spectroscopic and ultrasonic methods are comparable and follow similar trends. The trend in the formation constants is discussed with structures of the components. The thermodynamic behavior of the systems was explained through the computed values of the free energy ({Delta}G), enthalpy ({Delta}H) and entropy ({Delta}S) changes for complex formation are computed and discussed.

Dissociative, depressive, and PTSD symptom severity as correlates of nonsuicidal self-injury and suicidality in dissociative disorder patients.

Science.gov (United States)

Webermann, Aliya R; Myrick, Amie C; Taylor, Christina L; Chasson, Gregory S; Brand, Bethany L

2016-01-01

The present study investigates whether symptom severity can distinguish patients diagnosed with dissociative identity disorder and dissociative disorder not otherwise specified with a recent history of nonsuicidal self-injury (NSSI) and suicide attempts from those patients without recent self-harm. A total of 241 clinicians reported on recent history of patient NSSI and suicide attempts. Of these clinicians' patients, 221 completed dissociative, depressive, and posttraumatic stress disorder symptomatology measures. Baseline cross-sectional data from a naturalistic and prospective study of dissociative disorder patients receiving community treatment were utilized. Analyses evaluated dissociative, depressive, and posttraumatic stress disorder symptom severity as methods of classifying patients into NSSI and suicide attempt groupings. Results indicated that dissociation severity accurately classified patients into NSSI and suicidality groups, whereas depression severity accurately classified patients into NSSI groups. These findings point to dissociation and depression severity as important correlates of NSSI and suicidality in patients with dissociative disorders and have implications for self-harm prevention and treatment.

Determination of the dissociation constant of molten Li/sub 2/CO/sub 3//Na/sub 2/CO/sub 3//K/sub 2/CO/sub 3/ using a stabilized zirconia oxide-ion indicator

Energy Technology Data Exchange (ETDEWEB)

Ito, Yasuhiko; Tsuru, Kiyoshi; Oishi, Jun; Miyazaki, Yoshinori; Kodama, Teruo

1985-09-01

An Li/sub 2/CO/sub 3//Na/sub 2/CO/sub 3//K/sub 2/CO/sub 3/ eutectic melt has been selected as an example of a molten-carbonate system and the suitability of a stabilized zirconia-air electrode as an oxide-ion concentration indicator for this melt has been confirmed. With this indicator, the dissociation constant of the reaction CO/sub 3//sup 2 -/(l)=CO/sub 2/(g)+O/sup 2 -/(l) in this melt has been determined to be Ksub(d)=P sub(CO/sub 2/) (O/sup 2 -/)=4.03 x 10/sup -3/ Pa at 873 K. Reproducible measurements were obtained throughout the experiment and this method might find further application in the study of reactions related to the oxide ion in carbonate melts. (orig.).

Dissociation dynamics of methylal

Energy Technology Data Exchange (ETDEWEB)

Beaud, P; Frey, H -M; Gerber, T; Mischler, B; Radi, P P; Tzannis, A -P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

First-Principle Calculations for Elastic and Thermodynamic Properties of Diamond

International Nuclear Information System (INIS)

Fu Zhijian; Chen Xiangrong; Gou Qingquan; Ji Guangfu

2009-01-01

The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTAL03 program. The lattice parameters, the bulk modulus, the heat capacity, the Grueneisen parameter, and the Debye temperature are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V 0 and pressure, the elastic constants under high pressure are successfully obtained. Especially, the elastic constants of diamond under high pressure are firstly obtained theoretically. At the same time, the variations of the thermal expansion α with pressure P and temperature Tare obtained systematically in the ranges of 0-870 GPa and 0-1600 K. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Illusion thermal device based on material with constant anisotropic thermal conductivity for location camouflage

Science.gov (United States)

Hou, Quanwen; Zhao, Xiaopeng; Meng, Tong; Liu, Cunliang

2016-09-01

Thermal metamaterials and devices based on transformation thermodynamics often require materials with anisotropic and inhomogeneous thermal conductivities. In this study, still based on the concept of transformation thermodynamics, we designed a planar illusion thermal device, which can delocalize a heat source in the device such that the temperature profile outside the device appears to be produced by a virtual source at another position. This device can be constructed by only one kind of material with constant anisotropic thermal conductivity. The condition which should be satisfied by the device is provided, and the required anisotropic thermal conductivity is then deduced theoretically. This study may be useful for the designs of metamaterials or devices since materials with constant anisotropic parameters have great facility in fabrication. A prototype device has been fabricated based on a composite composed by two naturally occurring materials. The experimental results validate the effectiveness of the device.

Information Thermodynamics of Cytosine DNA Methylation.

Directory of Open Access Journals (Sweden)

Robersy Sanchez

Full Text Available Cytosine DNA methylation (CDM is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background ("noise" induced by thermal fluctuations. Here, we propose a novel statistical and information thermodynamic description of the CDM changes to address the last question. The physical basis of our statistical mechanical model was evaluated in two respects: 1 the adherence to Landauer's principle, according to which molecular machines must dissipate a minimum energy ε = kBT ln2 at each logic operation, where kB is the Boltzmann constant, and T is the absolute temperature and 2 whether or not the binary stretch of methylation marks on the DNA molecule comprise a language of sorts, properly constrained by thermodynamic principles. The study was performed for genome-wide methylation data from 152 ecotypes and 40 trans-generational variations of Arabidopsis thaliana and 93 human tissues. The DNA persistence length, a basic mechanical property altered by CDM, was estimated with values from 39 to 66.9 nm. Classical methylome analysis can be retrieved by applying information thermodynamic modelling, which is able to discriminate signal from noise. Our finding suggests that the CDM signal comprises a language scheme properly constrained by molecular thermodynamic principles, which is part of an epigenomic communication system that obeys the same thermodynamic

Thermodynamics

CERN Document Server

Fermi, Enrico

1956-01-01

Indisputably, this is a modern classic of science. Based on a course of lectures delivered by the author at Columbia University, the text is elementary in treatment and remarkable for its clarity and organization. Although it is assumed that the reader is familiar with the fundamental facts of thermometry and calorimetry, no advanced mathematics beyond calculus is assumed.Partial contents: thermodynamic systems, the first law of thermodynamics (application, adiabatic transformations), the second law of thermodynamics (Carnot cycle, absolute thermodynamic temperature, thermal engines), the entr

Thermodynamics and kinetics of RNA tertiary structure formation in the junctionless hairpin ribozyme.

Science.gov (United States)

White, Neil A; Hoogstraten, Charles G

2017-09-01

The hairpin ribozyme consists of two RNA internal loops that interact to form the catalytically active structure. This docking transition is a rare example of intermolecular formation of RNA tertiary structure without coupling to helix annealing. We have used temperature-dependent surface plasmon resonance (SPR) to characterize the thermodynamics and kinetics of RNA tertiary structure formation for the junctionless form of the ribozyme, in which loops A and B reside on separate molecules. We find docking to be strongly enthalpy-driven and to be accompanied by substantial activation barriers for association and dissociation, consistent with the structural reorganization of both internal loops upon complex formation. Comparisons with the parallel analysis of a ribozyme variant carrying a 2'-O-methyl modification at the self-cleavage site and with published data in other systems reveal a surprising diversity of thermodynamic signatures, emphasizing the delicate balance of contributions to the free energy of formation of RNA tertiary structure. Copyright © 2017 Elsevier B.V. All rights reserved.

The Shutdown Dissociation Scale (Shut-D)

Science.gov (United States)

Schalinski, Inga; Schauer, Maggie; Elbert, Thomas

2015-01-01

The evolutionary model of the defense cascade by Schauer and Elbert (2010) provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D) was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity). A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups) from healthy controls. The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding. PMID:25976478

The Shutdown Dissociation Scale (Shut-D

Directory of Open Access Journals (Sweden)

Inga Schalinski

2015-05-01

Full Text Available The evolutionary model of the defense cascade by Schauer and Elbert (2010 provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity.A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups from healthy controls.The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding.

The Dissociative Subtype of Posttraumatic Stress Disorder (PTSD) Among Adolescents: Co-Occurring PTSD, Depersonalization/Derealization, and Other Dissociation Symptoms.

Science.gov (United States)

Choi, Kristen R; Seng, Julia S; Briggs, Ernestine C; Munro-Kramer, Michelle L; Graham-Bermann, Sandra A; Lee, Robert C; Ford, Julian D

2017-12-01

The purpose of this study was to examine the co-occurrence of posttraumatic stress disorder (PTSD) and dissociation in a clinical sample of trauma-exposed adolescents by evaluating evidence for the depersonalization/derealization dissociative subtype of PTSD as defined by the DSM-5 and then examining a broader set of dissociation symptoms. A sample of treatment-seeking, trauma-exposed adolescents 12 to 16 years old (N = 3,081) from the National Child Traumatic Stress Network Core Data Set was used to meet the study objectives. Two models of PTSD/dissociation co-occurrence were estimated using latent class analysis, one with 2 dissociation symptoms and the other with 10 dissociation symptoms. After model selection, groups within each model were compared on demographics, trauma characteristics, and psychopathology. Model A, the depersonalization/derealization model, had 5 classes: dissociative subtype/high PTSD; high PTSD; anxious arousal; dysphoric arousal; and a low symptom/reference class. Model B, the expanded dissociation model, identified an additional class characterized by dissociative amnesia and detached arousal. These 2 models provide new information about the specific ways PTSD and dissociation co-occur and illuminate some differences between adult and adolescent trauma symptom expression. A dissociative subtype of PTSD can be distinguished from PTSD alone in adolescents, but assessing a wider range of dissociative symptoms is needed to fully characterize adolescent traumatic stress responses. Copyright © 2017 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Dissociation Energies of Diatomic Molecules

International Nuclear Information System (INIS)

Qun-Chao, Fan; Wei-Guo, Sun

2008-01-01

Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7 LiD, 7 LiH, 6 LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy–Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies D e theory , which are in excellent agreement with the experimental dissociation energies D e expt . (atomic and molecular physics)

Thermodynamic tables for nuclear waste isolation

International Nuclear Information System (INIS)

Phillips, S.L.; Hale, F.V.; Silvester, L.F.; Siegel, M.D.

1988-05-01

Tables of consistent thermodynamic property values for nuclear waste isolation are given. The tables include critically assessed values for Gibbs energy of formation, enthalpy of formation, entropy and heat capacity for minerals; solids; aqueous ions; ion pairs and complex ions of selected actinide and fission decay products at 25 degree C and zero ionic strength. These intrinsic data are used to calculate equilibrium constants and standard potentials which are compared with typical experimental measurements and other work. Recommendations for additional research are given. 13 figs., 23 tabs

Thermodynamic data for predicting concentrations of Pu(III), Am(III), and Cm(III) in geologic environments

Energy Technology Data Exchange (ETDEWEB)

Rai, Dhanpat; Rao, Linfeng; Weger, H.T.; Felmy, A.R. [Pacific Northwest National Laboratory, WA (United States); Choppin, G.R. [Florida State University, Florida (United States); Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan)

1999-01-01

This report provides thermodynamic data for predicting concentrations of Pu(III), Am(III), and Cm(III) in geologic environments, and contributes to an integration of the JNC chemical thermodynamic database, JNC-TDB (previously PNC-TDB), for the performance analysis of geological isolation system for high-level radioactive wastes. Thermodynamic data for the formation of complexes or compounds with hydroxide, chloride, fluoride, carbonate, nitrate, sulfate and phosphate are discussed in this report. Where data for specific actinide(III) species are lacking, the data were selected based on chemical analogy to other trivalent actinides. In this study, the Pitzer ion-interaction model is mainly used to extrapolate thermodynamic constants to zero ionic strength at 25degC. (author)

The thermodynamics of protein folding: a critique of widely used quasi-thermodynamic interpretations and a restatement based on the Gibbs-Duhem relation and consistent with the Phase Rule.

Science.gov (United States)

Pethica, Brian A

2010-07-21

Interpretations of data in the extensive literature on the unfolding of proteins in aqueous solution follow a variety of methods involving assumptions leading to estimates of thermodynamic quantities associated with the unfolding transition. Inconsistencies and thermodynamic errors in these methods are identified. Estimates of standard molar free energies and enthalpies of unfolding using incompletely defined equilibrium constants and the van't Hoff relation are unsound, and typically contradict model-free interpretation of the data. A widely used routine for estimating the change in heat capacity associated with unfolding based on changes in the unfolding temperature and enthalpy co-induced by addition of denaturant or protective additives is thermodynamically incorrect by neglect of the Phase Rule. Many models and simulations predicting thermodynamic measures of unfolding are presently making comparisons with insecure quantities derived by incorrect thermodynamic analyses of experimental data. Analysis of unfolding via the Gibbs-Duhem equation with the correct Phase Rule constraints avoids the assumptions associated with incomplete equilibrium constants and misuse of the van't Hoff relation, and applies equally to positive, negative, sitewise or diffuse solute binding to the protein. The method gives the necessary relations between the thermodynamic parameters for thermal and isothermal unfolding and is developed for the case of two-state unfolding. The differences in binding of denaturants or stabilizers to the folded and unfolded forms of the protein are identified as major determinants of the unfolding process. The Phase Rule requires the temperature and enthalpy of unfolding to depend generally on the protein concentration. The available evidence bears out this expectation for thermal unfolding, indicating that protein-protein interactions influence folding. A parallel dependence of the denaturant concentrations for isothermal unfolding on the protein

Thermodynamic properties of the amorphous and crystalline modifications of carbon and the metastable synthesis of diamond

Energy Technology Data Exchange (ETDEWEB)

Guencheva, V.; Grantscharova, E.; Gutzow, I. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Physical Chemistry

2001-07-01

The temperature dependencies of the thermodynamic properties of the little known (or even hypothetical) undercooled carbon melt and of the glasses that could be obtained from it at appropriate cooling rates are constructed. This is done using both a general thermodynamic formalism to estimate equilibrium properties of undercooled glass-forming melts and the expected analogy in properties of Fourth Group Elements. A comparison of the hypothetical carbon glasses with amorphous materials, obtained by the pyrolisis of organic resins, usually called vitreous (or glassy) carbon, is made. It turns out that from a thermodynamic point of view existing vitreous carbon materials, although characterized by an amorphous, frozen-in structure, differ significantly from the carbon glasses, which could be obtained by a splat-cool-quench of the carbon melt. It is shown also that the hypothetical carbon glasses should have at any temperature a thermodynamic potential, significantly higher than that of diamond. Thus they could be used as a source of constant supersaturation in metastable diamond synthesis. Existing amorphous carbon materials, although showing considerably lower thermodynamic potentials than the hypothetical carbon glasses, could also be used as sources of constant supersaturation in a process of isothermal diamond synthesis if their thermodynamic potential is additionally increased (e.g. by mechano-chemical treatment or by dispersion into nano-size scale). Theoretical estimates made in terms of Ostwald's Rule of Stages indicate that in processes of metastable isothermal diamond synthesis additional kinetic factors (e.g. influencing the formation of sp{sup 3} - carbon structures in the ambient phase) and the introduction of active substrates (e.g. diamond powder) are to be of significance in the realization of this thermodynamic possibility. (orig.)

Dissociative amnesia in dissociative disorders and borderline personality disorder: self-rating assessment in a college population.

Science.gov (United States)

Sar, Vedat; Alioğlu, Firdevs; Akyuz, Gamze; Karabulut, Sercan

2014-01-01

Dissociative amnesia (DA) among subjects with a dissociative disorder and/or borderline personality disorder (BPD) recruited from a nonclinical population was examined. The Steinberg Dissociative Amnesia Questionnaire (SDAQ), the Childhood Trauma Questionnaire, and the self-report screening tool of the BPD section of the Structured Clinical Interview for DSM-IV(SCID-BPD) were administered to 1,301 college students. A total of 80 participants who were diagnosed with BPD according to the clinician-administered SCID-BPD and 111 nonborderline controls were evaluated using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D) by a psychiatrist blind to diagnosis and scale scores. Internal consistency analyses and test-retest evaluations suggested that the SDAQ is a reliable instrument for the population studied. Of the participants, 20.6% reported an SDAQ score of 20 or above and impairment by DA. Those who had both dissociative disorder and BPD (n = 78) had the highest SDAQ scores. Both disorders had significant effects on the SCID-D total and amnesia scores in the variance analysis. On SDAQ scores, however, only BPD had this effect. There was a significant interaction between the 2 disorders for the SCID-D total but not for the SDAQ or SCID-D amnesia scores. BPD represented the severity of dissociation and childhood trauma in this study group. However, in contrast to the dissociative disorders, BPD was characterized by better awareness of DA in self-report. The discrepancies between self-report and clinical interview associated with BPD and dissociative disorders are discussed in the context of betrayal theory (J. J. Freyd, 1994) of BPD and perceptual theory (D. B. Beere, 2009) of dissociative disorders.

A consistent model for the equilibrium thermodynamic functions of partially ionized flibe plasma with Coulomb corrections

International Nuclear Information System (INIS)

Zaghloul, Mofreh R.

2003-01-01

Flibe (2LiF-BeF2) is a molten salt that has been chosen as the coolant and breeding material in many design studies of the inertial confinement fusion (ICF) chamber. Flibe plasmas are to be generated in the ICF chamber in a wide range of temperatures and densities. These plasmas are more complex than the plasma of any single chemical species. Nevertheless, the composition and thermodynamic properties of the resulting flibe plasmas are needed for the gas dynamics calculations and the determination of other design parameters in the ICF chamber. In this paper, a simple consistent model for determining the detailed plasma composition and thermodynamic functions of high-temperature, fully dissociated and partially ionized flibe gas is presented and used to calculate different thermodynamic properties of interest to fusion applications. The computed properties include the average ionization state; kinetic pressure; internal energy; specific heats; adiabatic exponent, as well as the sound speed. The presented results are computed under the assumptions of local thermodynamic equilibrium (LTE) and electro-neutrality. A criterion for the validity of the LTE assumption is presented and applied to the computed results. Other attempts in the literature are assessed with their implied inaccuracies pointed out and discussed

Diffusivity, solubility and thermodynamic modelling of diffusion growth of Ga"3"+-doped LiTaO_3 thin film for integrated optics

International Nuclear Information System (INIS)

Zhang, De-Long; Zhang, Qun; Zhang, Pei; Kang, Jian; Wong, Wing-Han; Yu, Dao-Yin

2016-01-01

Graphical abstract: Diffusion growth of Ga"3"+-doped LiTaO_3(LT) thin film was studied thermodynamically. Some Ga"3"+-doped LT thin films were grown on LT surface by in-diffusion of homogeneously coated Ga_2O_3 film at the temperature range of (1273 to 1473) K. The Ga"3"+ profile in the grown thin film was analyzed by secondary ion mass spectrometry. Form the measured Ga"3"+ profiles, some thermodynamic parameters were obtained. These include diffusivity, diffusion constant, chemical activation energy, solubility, solubility constant and enthalpy of solution. These parameters are crucial to design and growth of a Ga"3"+-doped LT thin film with desired Ga"3"+ profile for integrated optics application. A thermodynamic model is suggested for the growth and verified experimentally. - Highlights: • Diffusion growth of Ga"3"+-doped LiTaO_3 thin film were studied thermodynamically. • Diffusion constant is 1.41 · 10"−"6 m"2/s and activation energy is 237.2 kJ/mol. • Solubility constant is 22.9 · 10"2"6 ions/m"3 and enthalpy of solution is 28.9 kJ/mol. • Ga"3"+ dopant has small effect on LiTaO_3 refractive index. • Ga"3"+ growth can be described by a Fick-type equation with a constant diffusivity. - Abstract: A thermodynamic study was performed on diffusion growth of Ga"3"+-doped LiTaO_3(LT) thin film for integrated optics. Some Ga"3"+-doped LT thin films were grown on LT surface by in-diffusion of homogeneously coated Ga_2O_3 film at the temperature range of (1273 to 1473) K. After growth, the refractive indices at Ga"3"+-doped and un-doped surface parts were measured by prism coupling technique and Li composition there was evaluated from the measured refractive indices. The results show that Ga"3"+ dopant has small effect on the LT index. Li_2O out-diffusion is not measurable. The Ga"3"+ profile in the grown thin film was analysed by secondary ion mass spectrometry. It is found that the grown Ga"3"+ ions follow a complementary error function profile. A

[Clinical Handling of Patients with Dissociative Disorders].

Science.gov (United States)

Okano, Kenichiro

2015-01-01

This paper discusses the way informed psychiatrists are expected to handle dissociative patients in clinical situations, with a specific focus on dissociative identity disorders and dissociative fugue. On the initial interview with dissociative patients, information on their history of trauma and any nascent dissociative symptoms in their childhood should be carefully obtained. Their level of stress in their current life should also be assessed in order to understand their symptomatology, as well as to predict their future clinical course. A psychoeducational approach is crucial; it might be helpful to give information on dissociative disorder to these patients as well as their family members in order to promote their adherence to treatment. Regarding the symptomatology of dissociative disorders, detailed symptoms and the general clinical course are presented. It was stressed that dissociative identity disorder and dissociative fugue, the most high-profile dissociative disorders, are essentially different in their etiology and clinical presentation. Dissociative disorders are often confused with and misdiagnosed as psychotic disorders, such as schizophrenia. Other conditions considered in terms of the differential diagnosis include borderline personality disorder as well as temporal lobe epilepsy. Lastly, the therapeutic approach to dissociative identity disorder is discussed. Each dissociative identity should be understood as potentially representing some traumatically stressful event in the past. The therapist should be careful not to excessively promote the creation or elaboration of any dissociative identities. Three stages are proposed in the individual psychotherapeutic process. In the initial stage, a secure environment and stabilization of symptoms should be sought. The second stage consists of aiding the "host" personality to make use of other more adaptive coping skills in their life. The third stage involves coaching as well as continuous awareness of

Direct measurement of newly synthesized ATP dissociation kinetics in sarcoplasmic reticulum ATPase

International Nuclear Information System (INIS)

Teruel-Puche, J.; Kurzmack, M.; Inesi, G.

1987-01-01

Incubation of SR vesicles with Ca 2+ and ( 32 P)acetylphosphate, yields steady state levels of ( 32 P)phosphorylated enzyme (ATPase) intermediate and high concentrations of Ca 2+ in the lumen of the vesicles. At this time, addition of ADP (and EGTA to lower the Ca 2+ concentration in the medium outside the vesicles) results in single cycle formation of (γ- 32 P)ATP by transfer of ( 32 P)phosphate from the enzyme intermediate to ADP. The phosphoenzyme decay and ATP formation exhibit a fast component within the first 20 msec following addition of ADP, and a slower component reaching an asymptote in approximately 100 msec. They have now measured by a rapid filtration method the fraction of newly synthesized ATP which is bound to the enzyme, as opposed to the fraction dissociated into the medium. They find that nearly all the ATP formed during the initial burst is still bound to the enzyme within the initial 20 msec of reaction. Dissociation of newly synthesized ATP occurs then with approximately 13 sec -1 rate constant, permitting reequilibration of the system and further formation of ATP. The rate limiting effect of ATP dissociation and other partial reactions on the slow component of single cycle ATP synthesis is evaluated by appropriate kinetic simulations

Thermodynamic restrictions on linear reversible and irreversible thermo-electro-magneto-mechanical processes

Directory of Open Access Journals (Sweden)

Sushma Santapuri

2016-10-01

Full Text Available A unified thermodynamic framework for the characterization of functional materials is developed. This framework encompasses linear reversible and irreversible processes with thermal, electrical, magnetic, and/or mechanical effects coupled. The comprehensive framework combines the principles of classical equilibrium and non-equilibrium thermodynamics with electrodynamics of continua in the infinitesimal strain regime.In the first part of this paper, linear Thermo-Electro-Magneto-Mechanical (TEMM quasistatic processes are characterized. Thermodynamic stability conditions are further imposed on the linear constitutive model and restrictions on the corresponding material constants are derived. The framework is then extended to irreversible transport phenomena including thermoelectric, thermomagnetic and the state-of-the-art spintronic and spin caloritronic effects. Using Onsager's reciprocity relationships and the dissipation inequality, restrictions on the kinetic coefficients corresponding to charge, heat and spin transport processes are derived. All the constitutive models are accompanied by multiphysics interaction diagrams that highlight the various processes that can be characterized using this framework. Keywords: Applied mathematics, Materials science, Thermodynamics

Bethe ansatz approach to quantum sine Gordon thermodynamics and finite temperature excitations

International Nuclear Information System (INIS)

Zotos, X.

1982-01-01

Takahashi and Suzuki (TS) using the Bethe ansatz method developed a formalism for the thermodynamics of the XYZ spin chain. Translating their formalism to the quantum sine-Gordon system, the thermodynamics and finite temperature elementary excitations are analyzed. Criteria imposed by TS on the allowed states simply correspond to the condition of normalizability of the wave functions. A set of coupled nonlinear integral equations for the thermodynamic equilibrium densities for particular values of the coupling constant in the attractive regime is derived. Solving numerically these Bethe ansatz equations, curves of the specific heat as a function of temperature are obtained. The soliton contribution peaks at a temperature of about 0.4 soliton masses shifting downward as the classical limit is approached. The weak coupling regime is analyzed by deriving the Bethe ansatz equations including the charged vacuum excitations. It is shown that they are necessary for a consistent presentation of the thermodynamics

Thermodynamics of the CSCl-H{sub 2}O system at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Monnin, C. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France). Lab. de Geochimie; Dubois, M. [Centre National de la Recherche Scientifique (CNRS), 59 - Villeneuve d`Ascq (France). Lab. de Sedimentologie et Geodynamique

1999-05-01

The interpretation of fluid-inclusion data requires knowledge of phase diagrams at low (subfreezing) temperatures. From the example of the CsCl-H{sub 2}O system, we here investigate the possibility to build such diagrams from thermodynamic models of aqueous solutions parameterized at higher temperatures. Holmes and Mesmer (1983) have built a model for the thermodynamic properties of CsCl(aq) based on Pitzer`s equation fit to thermodynamic data mainly at temperatures above 0 C along with a few freezing-point-depression data down to -8 C. We show how this model can be used along with the published water-ice equilibrium constant and thermodynamic data at 25 C for Cs{sup +}(aq), Cl{sup -}(aq) and CsCl(s), to predict with confidence the ice-liquid-vapor (ILV) and the salt-liquid-vapor (SLV) curves down to the eutectic temperature for the CsCl-H{sub 2}O system. (orig.)

Statistical thermodynamics

International Nuclear Information System (INIS)

Lim, Gyeong Hui

2008-03-01

This book consists of 15 chapters, which are basic conception and meaning of statistical thermodynamics, Maxwell-Boltzmann's statistics, ensemble, thermodynamics function and fluctuation, statistical dynamics with independent particle system, ideal molecular system, chemical equilibrium and chemical reaction rate in ideal gas mixture, classical statistical thermodynamics, ideal lattice model, lattice statistics and nonideal lattice model, imperfect gas theory on liquid, theory on solution, statistical thermodynamics of interface, statistical thermodynamics of a high molecule system and quantum statistics

Quantum foam, gravitational thermodynamics, and the dark sector

International Nuclear Information System (INIS)

Ng, Y. Jack

2017-01-01

Is it possible that the dark sector (dark energy in the form of an effective dynamical cosmological constant, and dark matter) has its origin in quantum gravity? This talk sketches a positive response. Here specifically quantum gravity refers to the combined effect of quantum foam (or spacetime foam due to quantum fluctuations of spacetime) and gravitational thermodynamics. We use two simple independent gedankan experiments to show that the holographic principle can be understood intuitively as having its origin in the quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant of the observed magnitude, a result that can also be obtained for the present and recent cosmic eras by using unimodular gravity and causal set theory. Next we generalize the concept of gravitational thermodynamics to a spacetime with positive cosmological constant (like ours) to reveal the natural emergence, in galactic dynamics, of a critical acceleration parameter related to the cosmological constant. We are then led to construct a phenomenological model of dark matter which we call “modified dark matter” (MDM) in which the dark matter density profile depends on both the cosmological constant and ordinary matter. We provide observational tests of MDM by fitting the rotation curves to a sample of 30 local spiral galaxies with a single free parameter and by showing that the dynamical and observed masses agree in a sample of 93 galactic clusters. We also give a brief discussion of the possibility that quanta of both dark energy and dark matter are non-local, obeying quantum Boltzmann statistics (also called infinite statistics) as described by a curious average of the bosonic and fermionic algebras. If such a scenario is correct, we can expect some novel particle phenomenology involving dark matter interactions. This may explain why so far no dark matter detection experiments have been able to claim convincingly to have detected

Quantum foam, gravitational thermodynamics, and the dark sector

Science.gov (United States)

Ng, Y. Jack

2017-05-01

Is it possible that the dark sector (dark energy in the form of an effective dynamical cosmological constant, and dark matter) has its origin in quantum gravity? This talk sketches a positive response. Here specifically quantum gravity refers to the combined effect of quantum foam (or spacetime foam due to quantum fluctuations of spacetime) and gravitational thermodynamics. We use two simple independent gedankan experiments to show that the holographic principle can be understood intuitively as having its origin in the quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant of the observed magnitude, a result that can also be obtained for the present and recent cosmic eras by using unimodular gravity and causal set theory. Next we generalize the concept of gravitational thermodynamics to a spacetime with positive cosmological constant (like ours) to reveal the natural emergence, in galactic dynamics, of a critical acceleration parameter related to the cosmological constant. We are then led to construct a phenomenological model of dark matter which we call “modified dark matter” (MDM) in which the dark matter density profile depends on both the cosmological constant and ordinary matter. We provide observational tests of MDM by fitting the rotation curves to a sample of 30 local spiral galaxies with a single free parameter and by showing that the dynamical and observed masses agree in a sample of 93 galactic clusters. We also give a brief discussion of the possibility that quanta of both dark energy and dark matter are non-local, obeying quantum Boltzmann statistics (also called infinite statistics) as described by a curious average of the bosonic and fermionic algebras. If such a scenario is correct, we can expect some novel particle phenomenology involving dark matter interactions. This may explain why so far no dark matter detection experiments have been able to claim convincingly to have detected

Thermodynamics and proton activities of protic ionic liquids with quantum cluster equilibrium theory

Science.gov (United States)

Ingenmey, Johannes; von Domaros, Michael; Perlt, Eva; Verevkin, Sergey P.; Kirchner, Barbara

2018-05-01

We applied the binary Quantum Cluster Equilibrium (bQCE) method to a number of alkylammonium-based protic ionic liquids in order to predict boiling points, vaporization enthalpies, and proton activities. The theory combines statistical thermodynamics of van-der-Waals-type clusters with ab initio quantum chemistry and yields the partition functions (and associated thermodynamic potentials) of binary mixtures over a wide range of thermodynamic phase points. Unlike conventional cluster approaches that are limited to the prediction of thermodynamic properties, dissociation reactions can be effortlessly included into the bQCE formalism, giving access to ionicities, as well. The method is open to quantum chemical methods at any level of theory, but combination with low-cost composite density functional theory methods and the proposed systematic approach to generate cluster sets provides a computationally inexpensive and mostly parameter-free way to predict such properties at good-to-excellent accuracy. Boiling points can be predicted within an accuracy of 50 K, reaching excellent accuracy for ethylammonium nitrate. Vaporization enthalpies are predicted within an accuracy of 20 kJ mol-1 and can be systematically interpreted on a molecular level. We present the first theoretical approach to predict proton activities in protic ionic liquids, with results fitting well into the experimentally observed correlation. Furthermore, enthalpies of vaporization were measured experimentally for some alkylammonium nitrates and an excellent linear correlation with vaporization enthalpies of their respective parent amines is observed.

Dissociation of ethane by electron impact

International Nuclear Information System (INIS)

Winters, H.F.

1979-01-01

The absolute total dissociation cross section for ethane is reported for electron energies between 10 and 600 eV. A maximum value of 7.6 X 10 -16 cm 2 occurs at 80 eV while the apparent threshold is approximately 10 eV. Dissociative ionization is more probable than dissociation into neutral fragments at all energies except in the threshold region. The data indicates that fragmentation involving methane elimination (e - +C 2 H 6 → CH 4 + CH 2 ) occurs in less than 2% of the dissociative events for 50 < E < 600 eV. Arguments are presented which suggest that some of the lower excited states of ethane are stable against dissociation. (Auth.)

Complexation of Am(III) by oxalate in NaClO4 media

International Nuclear Information System (INIS)

Choppin, G.R.; Chen, J.F.

1995-01-01

The complexation of Am(III) by oxalate has been investigated in solutions of NaClO 4 up to 9.0 M ionic strength at 25 degrees C. The dissociation constants of oxalic acid were determined by potentiometric titration, while the stability constants of the Am(III)-oxalate complexation were measured by the solvent extraction technique. A thermodynamic model was constructed to predict the apparent equilibrium constants at different ionic strengths by applying the Pitzer equation using parameters for the Na + -HOx - , Na + -Ox - , AmOx + -ClO 4 - , and Na + -Am(Ox) 2 - interactions obtained by fitting the data

The Importance of the Dissociation Rate in Ion Channel Blocking

Directory of Open Access Journals (Sweden)

Hugo Zeberg

2018-02-01

Full Text Available Understanding the relationships between the rates and dynamics of current wave forms under voltage clamp conditions is essential for understanding phenomena such as state-dependence and use-dependence, which are fundamental for the action of drugs used as anti-epileptics, anti-arrhythmics, and anesthetics. In the present study, we mathematically analyze models of blocking mechanisms. In previous experimental studies of potassium channels we have shown that the effect of local anesthetics can be explained by binding to channels in the open state. We therefore here examine models that describe the effect of a blocking drug that binds to a non-inactivating channel in its open state. Such binding induces an inactivation-like current decay at higher potential steps. The amplitude of the induced peak depends on voltage and concentration of blocking drug. In the present study, using analytical methods, we (i derive a criterion for the existence of a peak in the open probability time evolution for a model with an arbitrary number of closed states, (ii derive formula for the relative height of the peak amplitude, and (iii determine the voltage dependence of the relative peak height. Two findings are apparent: (1 the dissociation (unbinding rate constant is important for the existence of a peak in the current waveform, while the association (binding rate constant is not, and (2 for a peak to exist it suffices that the dissociation rate must be smaller than the absolute value of all eigenvalues to the kinetic matrix describing the model.

Thermodynamic and Quantum Thermodynamic Analyses of Brownian Movement

OpenAIRE

Gyftopoulos, Elias P.

2006-01-01

Thermodynamic and quantum thermodynamic analyses of Brownian movement of a solvent and a colloid passing through neutral thermodynamic equilibrium states only. It is shown that Brownian motors and E. coli do not represent Brownian movement.

Reconsidering the autohypnotic model of the dissociative disorders.

Science.gov (United States)

Dell, Paul F

2018-03-22

The dissociative disorders field and the hypnosis field currently reject the autohypnotic model of the dissociative disorders, largely because many correlational studies have shown hypnotizability and dissociation to be minimally related (r = .12). Curiously, it is also widely accepted that dissociative patients are highly hypnotizable. If dissociative patients are highly hypnotizable because only highly hypnotizable individuals can develop a dissociative disorder - as the author proposes - then the methodology of correlational studies of hypnotizability and dissociation in random clinical and community samples would necessarily be constitutively unable to detect, and statistically unable to reflect, that fact. That is, the autohypnotic, dissociative distancing of that small subset of highly hypnotizable individuals who repeatedly encountered intolerable circumstances is statistically lost among the data of (1) the highly hypnotizable subjects who do not dissociate and (2) subjects (of all levels of hypnotizability) who manifest other kinds of dissociation. The author proposes that, when highly hypnotizable individuals repeatedly engage in autohypnotic distancing from intolerable circumstances, they develop an overlearned, highly-motivated, automatized pattern of dissociative self-protection (i.e., a dissociative disorder). The author urges that theorists of hypnosis and the dissociative disorders explicitly include in their theories (a) the trait of high hypnotizability, (b) the phenomena of autohypnosis, and (c) the manifestations of systematized, autohypnotic pathology. Said differently, the author is suggesting that autohypnosis and autohypnotic pathology are unacknowledged nodes in the nomothetic networks of both hypnosis and dissociation.

Thermodynamics of high-temperature and high-density hadron gas by a numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Nobuo; Miyamura, Osamu [Hiroshima Univ., Higashi-Hiroshima (Japan). Dept. of Physics

1998-07-01

We study thermodynamical properties of hot and dense hadronic gas an event generator URASiMA. In our results, the increase of temperature is suppressed. It indicates that hot and dense hadronic gas has a large specific heat at constant volume. (author)

Testing the diagnosis of dissociative identity disorder through measures of dissociation, absorption, hypnotizability and PTSD: a Norwegian pilot study.

Science.gov (United States)

Dale, Karl Yngvar; Berg, Renate; Elden, Ake; Ødegård, Atle; Holte, Arne

2009-01-01

A total of 14 women meeting criteria for dissociative identity disorder (DID) based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]) were compared to a group of women (n = 10) with other dissociative diagnoses and a group of normal controls (n = 14) with regard to dissociativity, absorption, trauma related symptoms and hypnotizability. Both of the clinical groups reported histories of childhood trauma and attained high PTSD scores. The DID group differed significantly from the group with other dissociative diagnoses and the non-diagnosed comparison group with regard to hypnotizability, the variety of dissociative symptomatology, and the magnitude of dissociative symptomatology. However, no significant differences between the two clinical groups were detected with regard to absorption, general dissociative level, or symptoms related to traumatic stress. Results support the notion that DID can be regarded as a clinical entity which is separable from other dissociative disorders. Results also indicated that hypnotizability is the most important clinical feature of DID.

Advantage of TiF{sub 3} over TiCl{sub 3} as a dopant precursor to improve the thermodynamic property of Na{sub 3}AlH{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Kang Xiangdong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang Ping [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)]. E-mail: pingwang@imr.ac.cn; Cheng Huiming [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2007-03-15

The effect of the dopant anion on thermodynamic tailoring in TiF{sub 3}- and TiCl{sub 3}-doped Na{sub 3}AlH{sub 6} was investigated by pressure-composition desorption isotherm measurements. It was found that the dissociation pressure of the TiF{sub 3}-doped hydride was substantially higher than that of the TiCl{sub 3}-doped sample. This finding agrees well with the theoretically demonstrated thermodynamic modification arising upon F{sup -} substitution in the hydride lattice, thus providing direct experimental evidence to support functionality of F{sup -} anion.

Dissociation in undergraduate students: disruptions in executive functioning.

Science.gov (United States)

Giesbrecht, Timo; Merckelbach, Harald; Geraerts, Elke; Smeets, Ellen

2004-08-01

The concept of dissociation refers to disruptions in attentional control. Attentional control is an executive function. Few studies have addressed the link between dissociation and executive functioning. Our study investigated this relationship in a sample of undergraduate students (N = 185) who completed the Dissociative Experiences Scale and the Random Number Generation Task. We found that minor disruptions in executive functioning were related to a subclass of dissociative experiences, notably dissociative amnesia and the Dissociative Experiences Scale Taxon. However, the two other subscales of the Dissociative Experiences Scale, measuring depersonalization and absorption, were unrelated to executive functioning. Our findings suggest that a failure to inhibit previous responses might contribute to the pathological memory manifestations of dissociation.

Investigation of thermodynamic and mechanical properties of AlyIn1-yP alloys by statistical moment method

Science.gov (United States)

Ha, Vu Thi Thanh; Hung, Vu Van; Hanh, Pham Thi Minh; Tuyen, Nguyen Viet; Hai, Tran Thi; Hieu, Ho Khac

2018-03-01

The thermodynamic and mechanical properties of III-V zinc-blende AlP, InP semiconductors and their alloys have been studied in detail from statistical moment method taking into account the anharmonicity effects of the lattice vibrations. The nearest neighbor distance, thermal expansion coefficient, bulk moduli, specific heats at the constant volume and constant pressure of the zincblende AlP, InP and AlyIn1-yP alloys are calculated as functions of the temperature. The statistical moment method calculations are performed by using the many-body Stillinger-Weber potential. The concentration dependences of the thermodynamic quantities of zinc-blende AlyIn1-yP crystals have also been discussed and compared with those of the experimental results. Our results are reasonable agreement with earlier density functional theory calculations and can provide useful qualitative information for future experiments. The moment method then can be developed extensively for studying the atomistic structure and thermodynamic properties of nanoscale materials as well.

Two-temperature thermodynamic and transport properties of SF6–Cu plasmas

International Nuclear Information System (INIS)

Wu, Yi; Chen, Zhexin; Yang, Fei; Rong, Mingzhe; Sun, Hao; Cressault, Yann; Murphy, Anthony B; Guo, Anxiang; Liu, Zirui

2015-01-01

SF 6 and Cu are widely adopted in electrical equipment as a dielectric medium and for conductive components, respectively. SF 6 –Cu plasmas are frequently formed, particularly in high-voltage circuit breaker arcs and fault current arcs, due to erosion of the Cu components. In this paper, calculated values of the thermodynamic and transport properties of plasmas in SF 6 –Cu mixtures are presented for both thermal equilibrium and non-equilibrium conditions. The composition is determined by the two-temperature Saha equation and Guldberg–Waage equation in the form derived by van de Sanden. The composition and the thermodynamic properties are evaluated through a classical statistical mechanics approach. For the transport coefficients, the simplified Chapman–Enskog method developed by Devoto, which decouples the electrons and heavy species, has been applied using the most recent collision integrals. The thermodynamic and transport properties are calculated for different electron temperatures (300–40 000 K), ratios of electron to heavy-species temperature (1–10), pressures (0.1–10 atm) and copper molar proportions (0–50%). It is found that deviations from thermal equilibrium strongly affect the thermodynamic and transport properties of the SF 6 –Cu plasmas. Further, the presence of copper has different effects on some of the properties for plasmas in and out of thermal equilibrium. The main reason for these changes is that dissociation reactions are delayed for non-thermal equilibrium plasmas, which in turn influences the ionization reactions that occur. (paper)

A Concise Equation of State for Aqueous Solutions of Electrolytes Incorporating Thermodynamic Laws and Entropy

Directory of Open Access Journals (Sweden)

Raji Heyrovská

2004-03-01

Full Text Available Abstract: Recently, the author suggested a simple and composite equation of state by incorporating fundamental thermodynamic properties like heat capacities into her earlier concise equation of state for gases based on free volume and molecular association / dissociation. This work brings new results for aqueous solutions, based on the analogy of the equation of state for gases and solutions over wide ranges of pressures (for gases and concentrations (for solutions. The definitions of entropy and heat energy through the equation of state for gases, also holds for solutions.

Basic Thermodynamics

International Nuclear Information System (INIS)

Duthil, P

2014-01-01

The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered

Basic Thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Duthil, P [Orsay, IPN (France)

2014-07-01

The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered.

Experimental thermodynamics experimental thermodynamics of non-reacting fluids

CERN Document Server

Neindre, B Le

2013-01-01

Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio

Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures

Science.gov (United States)

Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans

2009-02-01

For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.

Radical kinetics in sub- and supercritical carbon dioxide: thermodynamic rate tuning.

Science.gov (United States)

Ghandi, Khashayar; McFadden, Ryan M L; Cormier, Philip J; Satija, Paras; Smith, Marisa

2012-06-28

We report rate constants for muonium addition to 1,1-difluoroethylene (vinylidene fluoride) in CO2 at 290-530 K, 40-360 bar, and 0.05-0.90 g cm(-3). Rate constants are mapped against their thermodynamic conditions, demonstrating the kinetic tuning ability of the solvent. The reaction exhibits critical slowing near conditions of maximum solvent isothermal compressibility, where activation volumes of unprecedentedly large magnitudes on the order of ±10(6) cm(3) mol(-1) are observed. Such values are suggestive of pressure being a significant parameter for tuning fluorolkene reactivity.

Comparing the symptoms and mechanisms of "dissociation" in dissociative identity disorder and borderline personality disorder.

Science.gov (United States)

Laddis, Andreas; Dell, Paul F; Korzekwa, Marilyn

2017-01-01

A total of 75 patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised as having dissociative identity disorder (DID), and 100 patients were diagnosed with the Structured Interview for DSM-IV Personality as having borderline personality disorder (BPD). Both groups were administered the Multidimensional Inventory of Dissociation (MID). DID patients had significantly higher MID scores than BPD patients, different distributions of MID scores, and different MID subscale profiles in 3 ranges of MID scores (0-15, 15-30, 30-45). The core MID symptoms-exhibited at all ranges of MID scores-for DID patients (the presence of alters, identity confusion, and memory problems) and BPD patients (flashbacks, identity confusion, and memory problems) were ostensibly similar but were considered to be mostly produced by different underlying processes. Multiple regression analyses showed that the core MID symptoms of DID patients had different predictors than did the core MID symptoms of BPD patients. Alter identities seemed to generate most-but not all-dissociative phenomena in DID patients, whereas only the 24% highest scoring BPD patients (MID ≥45) seemed to manifest alter-driven dissociative experiences. Most BPD dissociative experiences appeared to be due to 5 other mechanisms: (a) BPD-specific, stress-driven, rapid shifts of self-state; (b and c) nondefensive disruptions of the framework of perceptual organization with or without an accompanying BPD-specific, dissociation-like disintegration of affective/neurocognitive functioning; (d) a defensive distancing or detachment from distress (i.e., simple depersonalization); and (e) Allen, Console, and Lewis's (1999) severe absorptive detachment.

Visuomotor Dissociation in Cerebral Scaling of Size.

Science.gov (United States)

Potgieser, Adriaan R E; de Jong, Bauke M

2016-01-01

Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity) or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity). These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8) revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a 'resized' virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space.

The role of equilibrium and kinetic properties in the dissociation of Gd[DTPA-bis(methylamide)] (Omniscan) at near to physiological conditions.

Science.gov (United States)

Baranyai, Zsolt; Brücher, Ernő; Uggeri, Fulvio; Maiocchi, Alessandro; Tóth, Imre; Andrási, Melinda; Gáspár, Attila; Zékány, László; Aime, Silvio

2015-03-16

[Gd(DTPA-BMA)] is the principal constituent of Omniscan, a magnetic resonance imaging (MRI) contrast agent. In body fluids, endogenous ions (Zn(2+), Cu(2+), and Ca(2+)) may displace the Gd(3+). To assess the extent of displacement at equilibrium, the stability constants of DTPA-BMA(3-) complexes of Gd(3+), Ca(2+), Zn(2+), and Cu(2+) have been determined at 37 °C in 0.15 M NaCl. The order of these stability constants is as follows: GdL≈CuL>ZnL≫CaL. Applying a simplified blood plasma model, the extent of dissociation of Omniscan (0.35 mM [Gd(DTPA-BMA)]) was found to be 17% by the formation of Gd(PO4), [Zn(DTPA-BMA)](-) (2.4%), [Cu(DTPA-BMA)](-) (0.2%), and [Ca(DTPA-BMA)](-) (17.7%). By capillary electrophoresis, the formation of [Ca(DTPA-BMA)](-) has been detected in human serum spiked with [Gd(DTPA-BMA)] (2.0 mM) at pH 7.4. Transmetallation reactions between [Gd(DTPA-BMA)] and Cu(2+) at 37 °C in the presence of citrate, phosphate, and bicarbonate ions occur by dissociation of the complex assisted by the endogenous ligands. At physiological concentrations of citrate, phosphate, and bicarbonate ions, the half-life of dissociation of [Gd(DTPA-BMA)] was calculated to be 9.3 h at pH 7.4. Considering the rates of distribution and dissociation of [Gd(DTPA-BMA)] in the extracellular space of the body, an open two-compartment model has been developed, which allows prediction of the extent of dissociation of the Gd(III) complex in body fluids depending on the rate of elimination of the contrast agent. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface thermodynamics

International Nuclear Information System (INIS)

Garcia-Moliner, F.

1975-01-01

Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions

Black Hole Thermodynamics in an Undergraduate Thermodynamics Course.

Science.gov (United States)

Parker, Barry R.; McLeod, Robert J.

1980-01-01

An analogy, which has been drawn between black hole physics and thermodynamics, is mathematically broadened in this article. Equations similar to the standard partial differential relations of thermodynamics are found for black holes. The results can be used to supplement an undergraduate thermodynamics course. (Author/SK)

Quantum Thermodynamics at Strong Coupling: Operator Thermodynamic Functions and Relations

Directory of Open Access Journals (Sweden)

Jen-Tsung Hsiang

2018-05-01

Full Text Available Identifying or constructing a fine-grained microscopic theory that will emerge under specific conditions to a known macroscopic theory is always a formidable challenge. Thermodynamics is perhaps one of the most powerful theories and best understood examples of emergence in physical sciences, which can be used for understanding the characteristics and mechanisms of emergent processes, both in terms of emergent structures and the emergent laws governing the effective or collective variables. Viewing quantum mechanics as an emergent theory requires a better understanding of all this. In this work we aim at a very modest goal, not quantum mechanics as thermodynamics, not yet, but the thermodynamics of quantum systems, or quantum thermodynamics. We will show why even with this minimal demand, there are many new issues which need be addressed and new rules formulated. The thermodynamics of small quantum many-body systems strongly coupled to a heat bath at low temperatures with non-Markovian behavior contains elements, such as quantum coherence, correlations, entanglement and fluctuations, that are not well recognized in traditional thermodynamics, built on large systems vanishingly weakly coupled to a non-dynamical reservoir. For quantum thermodynamics at strong coupling, one needs to reexamine the meaning of the thermodynamic functions, the viability of the thermodynamic relations and the validity of the thermodynamic laws anew. After a brief motivation, this paper starts with a short overview of the quantum formulation based on Gelin & Thoss and Seifert. We then provide a quantum formulation of Jarzynski’s two representations. We show how to construct the operator thermodynamic potentials, the expectation values of which provide the familiar thermodynamic variables. Constructing the operator thermodynamic functions and verifying or modifying their relations is a necessary first step in the establishment of a viable thermodynamics theory for

Thermodynamic tables to accompany Modern engineering thermodynamics

CERN Document Server

Balmer, Robert T

2011-01-01

This booklet is provided at no extra charge with new copies of Balmer's Modern Engineering Thermodynamics. It contains two appendices. Appendix C contains 40 thermodynamic tables, and Appendix D consists of 6 thermodynamic charts. These charts and tables are provided in a separate booklet to give instructors the flexibility of allowing students to bring the tables into exams. The booklet may be purchased separately if needed.

Inflight dissociation of zircon in air plasma

Energy Technology Data Exchange (ETDEWEB)

Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

2010-02-01

Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

Inflight dissociation of zircon in air plasma

International Nuclear Information System (INIS)

Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

2010-01-01

Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

Dissociative Part-Dependent Resting-State Activity in Dissociative Identity Disorder: A Controlled fMRI Perfusion Study

OpenAIRE

Schlumpf, Yolanda R.; Reinders, Antje A. T. S.; Nijenhuis, Ellert R. S.; Luechinger, Roger; van Osch, Matthias J. P.; Jäncke, Lutz

2014-01-01

Background: In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part'' (EP) and the "Apparently Normal Part'' (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors. Methods: Arterial ...

Adsorption and dissociation of H2S on Mo(1 0 0) surface by first-principles study

International Nuclear Information System (INIS)

Luo, Haijun; Cai, Jianqiu; Tao, Xiangming; Tan, Mingqiu

2014-01-01

Density-functional theory calculations had been used to investigate the adsorption and dissociation of H 2 S on Mo(1 0 0) surface. Adsorption mechanisms of H 2 S, HS, S and H on the Mo(1 0 0) surface were analyzed. H 2 S was found to be adsorbed at bridge, hollow and top sites with adsorption energies of −1.25, −1.03 and −0.92 eV, respectively. HS was strongly chemically absorbed at hollow, bridge and top sites with adsorption energies of −4.51, −4.08 and −3.45 eV, respectively, and sulfur and hydrogen preferred to be absorbed at hollow and bridge sites, respectively. In addition, potential energy profiles of H 2 S dissociation on Mo(1 0 0) had been constructed by a climbing image nudged elastic band method. Four possible dissociation pathways of the first H 2 S dehydrogenation were examined with reaction barriers of 0.28, 0.37, 0.075, and 0.21 eV, respectively, while the energy barrier to break the S-H bond of HS with or without hydrogen co-adsorption was almost the same low. This work showed that the decomposition of H 2 S on the molybdenum surface was kinetically and thermodynamically facile. Local densities of electronic states were further used to characterize the interaction between H 2 S and substrate.

High Temperature Phenomena in Shock Waves

CERN Document Server

2012-01-01

The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

[Questionnaire on dissociative symptoms. German adaptation, reliability and validity of the American Dissociative Experience Scale (DES)].

Science.gov (United States)

Freyberger, H J; Spitzer, C; Stieglitz, R D; Kuhn, G; Magdeburg, N; Bernstein-Carlson, E

1998-06-01

The "Fragebogen zu dissoziativen Symptomen (FDS)" represents the authorised German translation and adaptation of the "Dissociative Experience Scale" (DES; Bernstein and Putnam 1986). The original scale comprises 28 items covering dissociative experiences with regard to memory, identity, awareness and cognition according to DSM-III-R and DSM-IV. For the German version, 16 items were added to cover dissociative phenomena according to ICD-10, mainly pseudoneurological conversion symptoms. Reliability and validity of the German version were studied in a total sample of 813 persons and were compared to the results of the original version. Test-retest reliability of the FDS was rtt = 0.88 and Cronbach's consistency coefficient was alpha = 0.93, which is comparable to the results of the DES. The instrument differentiates between different samples (healthy control subjects, students, unselected neurological and psychiatric inpatients, neurological and psychiatric patients with a dissociative disorder and schizophrenics). The FDS is an easily applicable, reliable and valid measure to quantify dissociative experiences.

Ion association thermodynamics of alkali metal tetraphenylborates in the mixed solvent propylenecarbonate-1,2-dimethoxyethane

International Nuclear Information System (INIS)

Fialkov, Yu.Ya.; Gorbachev, V.Yu.

1997-01-01

Polythermal dependences of constants of ion association of (Li + -Cs + )BPh 4 salts in mixed solvent differ significantly in permittivity. Thermodynamic characteristics of this process are calculated and their relation with solvation processes is analyzed. (author)

Dissociative Disorders Among Chinese Inpatients Diagnosed With Schizophrenia

Science.gov (United States)

Yu, Junhan; Ross, Colin A.; Keyes, Benjamin B.; Li, Ying; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Fan, Qing; Xiao, Zeping

2010-01-01

The purpose of the study was to assess the prevalence of dissociative disorders in a sample of Chinese psychiatric inpatients. Participants in the study consisted of 569 consecutively admitted inpatients at Shanghai Mental Health Center, China, of whom 84.9% had a clinical diagnosis of schizophrenia based on the Chinese Classification and Diagnostic Criteria for Mental Disorders, Version 3 (CCMD-3). All participants completed a self-report measure of dissociation, the Dissociative Experiences Scale (DES) and none had a prior diagnosis of a dissociative disorder. Ninety-six randomly selected participants were interviewed with a structured interview, the Dissociative Disorders Interview Schedule (DDIS) and a clinical interview. These 96 patients did not differ significantly from the 473 patients who were not interviewed on any demographic measures or on the self-report measure dissociation. A total of 28 (15.3%, after weighting of the data) patients received a clinical diagnosis of a dissociative disorder based on DSM-IV-TR criteria. Dissociative identity disorder was diagnosed in 2 (0.53%, after weighting) patients. Compared to the patients without a dissociative disorder, patients with dissociative disorders were significantly more likely to report childhood abuse (57.1% versus 22.1%), but the two groups did not differ significantly on any demographic measures. Dissociative disorders were readily identified in an inpatient psychiatric population in China. PMID:20603768

Theoretical and experimental study: the size dependence of decomposition thermodynamics of nanomaterials

International Nuclear Information System (INIS)

Cui, Zixiang; Duan, Huijuan; Li, Wenjiao; Xue, Yongqiang

2015-01-01

In the processes of preparation and application of nanomaterials, the decomposition reactions of nanomaterials are often involved. However, there is a dramatic difference in decomposition thermodynamics between nanomaterials and the bulk counterparts, and the difference depends on the size of the particles that compose the nanomaterials. In this paper, the decomposition model of a nanoparticle was built, the theory of decomposition thermodynamics of nanomaterials was proposed, and the relations of the size dependence of thermodynamic quantities for the decomposition reactions were deduced. In experiment, taking the thermal decomposition of nano-Cu 2 (OH) 2 CO 3 with different particle sizes (the range of radius is at 8.95–27.4 nm) as a system, the reaction thermodynamic quantities were determined, and the regularities of size dependence of the quantities were summarized. These experimental regularities consist with the above thermodynamic relations. The results show that there is a significant effect of the size of particles composing a nanomaterial on the decomposition thermodynamics. When all the decomposition products are gases, the differences in thermodynamic quantities of reaction between the nanomaterials and the bulk counterparts depend on the particle size; while when one of the decomposition products is a solid, the differences depend on both the initial particle size of the nanoparticle and the decomposition ratio. When the decomposition ratio is very small, these differences are only related to the initial particle size; and when the radius of the nanoparticles approaches or exceeds 10 nm, the reaction thermodynamic functions and the logarithm of the equilibrium constant are linearly associated with the reciprocal of radius, respectively. The thermodynamic theory can quantificationally describe the regularities of the size dependence of thermodynamic quantities for decomposition reactions of nanomaterials, and contribute to the researches and the

Dissociative Tendencies and Traffic Incidents

Directory of Open Access Journals (Sweden)

Valle, Virginia

2012-01-01

Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

Thermodynamic data for predicting concentrations of Th(IV), U(IV), Np(IV), and Pu(IV) in geologic environments

Energy Technology Data Exchange (ETDEWEB)

Rai, Dhanpat; Roa, Linfeng; Weger, H.T.; Felmy, A.R. [Battelle, Pacific Northwest National Laboratory (PNNL) (United States); Choppin, G.R. [Florida State University (United States); Yui, Mikazu [Waste Isolation Research Division, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

1999-01-01

This report provides thermodynamic data for predicting concentrations of Th(IV), U(IV), Np(IV), and Pu(IV) in geologic environments, and contributes to an integration of the JNC chemical thermodynamic database, JNC-TDB (previously PNC-TDB), for the performance analysis of geological isolation system for high-level radioactive wastes. Thermodynamic data for the formation of complexes or compounds with hydroxide, chloride, fluoride, carbonate, nitrate, sulfate and phosphate are discussed in this report. Where data for specific actinide(IV) species was lacking, the data were selected based on chemical analogy to other tetravalent actinides. In this study, the Pitzer ion-interaction model is used to extrapolate thermodynamic constants to zero ionic strength at 25degC. (author)

Thermodynamic data development using the solubility method (Joint research)

International Nuclear Information System (INIS)

Rai, Dhanpat; Yui, Mikazu

2013-05-01

The solubility method is one of the most powerful tools to obtain reliable thermodynamic data for 1) solubility products of discrete solids and double salts, 2) complexation constants for various ligands, 3) development of data in a wide range of pH values, 4) evaluation of data for metals that form very insoluble solids (e.g. tetravalent actinides), 5) determining solubility-controlling solids in different types of wastes and 6) elevated temperatures for redox sensitive systems. This document is focused on describing various aspects of obtaining thermodynamic data using the solubility method. This manuscript deals with various aspects of conducting solubility studies, including selecting the study topic, modeling to define important variables, selecting the range of variables and experimental parameters, anticipating results, general equipment requirements, conducting experiments, and interpreting experimental data. (author)

Reduction of tungstates and molybdates by hydrogen and thermodynamic properties of these salts

International Nuclear Information System (INIS)

Gerasimov, Ya.I.; Rezukhina, T.N.; Simanov, Yu.P.; Vasil'eva, I.A.; Kurshakova, R.D.

1988-01-01

Study of thermodynamic properties of a series of tungstates of bivalent metals (Mg, Ca, Sr, Ba, Mn, Co, Fe, Ni, Cu, Zn, Cd and Pb) as well as of some molybdates- of Mg, Ca, Sr, Ba is carried out. The obtained values are compared with magnetic characteristics of compounds and parameters of their crystal lattices. Thermodynamic properties were studied by measuring constants of their reduction with hydrogen in the 500-1350 deg C temperature range. It is concluded that dependence of thermodynamic values on geometric parameters of the lattice is not definitive. Comparison of salt formation atomic entropies with deviations of salt magnetic moments from theoretical ionic moments points to the fact of existence of some accordance between these two series of values. 25 refs.; 10 figs.; 6 tabs

Non-hard sphere thermodynamic perturbation theory.

Science.gov (United States)

Zhou, Shiqi

2011-08-21

A non-hard sphere (HS) perturbation scheme, recently advanced by the present author, is elaborated for several technical matters, which are key mathematical details for implementation of the non-HS perturbation scheme in a coupling parameter expansion (CPE) thermodynamic perturbation framework. NVT-Monte Carlo simulation is carried out for a generalized Lennard-Jones (LJ) 2n-n potential to obtain routine thermodynamic quantities such as excess internal energy, pressure, excess chemical potential, excess Helmholtz free energy, and excess constant volume heat capacity. Then, these new simulation data, and available simulation data in literatures about a hard core attractive Yukawa fluid and a Sutherland fluid, are used to test the non-HS CPE 3rd-order thermodynamic perturbation theory (TPT) and give a comparison between the non-HS CPE 3rd-order TPT and other theoretical approaches. It is indicated that the non-HS CPE 3rd-order TPT is superior to other traditional TPT such as van der Waals/HS (vdW/HS), perturbation theory 2 (PT2)/HS, and vdW/Yukawa (vdW/Y) theory or analytical equation of state such as mean spherical approximation (MSA)-equation of state and is at least comparable to several currently the most accurate Ornstein-Zernike integral equation theories. It is discovered that three technical issues, i.e., opening up new bridge function approximation for the reference potential, choosing proper reference potential, and/or using proper thermodynamic route for calculation of f(ex-ref), chiefly decide the quality of the non-HS CPE TPT. Considering that the non-HS perturbation scheme applies for a wide variety of model fluids, and its implementation in the CPE thermodynamic perturbation framework is amenable to high-order truncation, the non-HS CPE 3rd-order or higher order TPT will be more promising once the above-mentioned three technological advances are established. © 2011 American Institute of Physics

Psychotherapy and pharmacotherapy for patients with dissociative identity disorder.

Science.gov (United States)

Gentile, Julie P; Dillon, Kristy S; Gillig, Paulette Marie

2013-02-01

There is a wide variety of what have been called "dissociative disorders," including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma report "dissociative" symptoms. Prevalence of dissociative disorders is unknown, but current estimates are higher than previously thought. This paper reviews clinical, phenomenological, and epidemiological data regarding diagnosis in general, and illustrates possible treatment interventions for dissociative identity disorder, with a focus on psychotherapy interventions and a review of current psychopharmacology recommendations as part of a comprehensive multidisciplinary treatment plan.

Thermodynamics of aqueous association and ionization reactions at high temperatures and pressures

International Nuclear Information System (INIS)

Mesmer, R.E.; Marshall, W.L.; Palmer, D.A.; Simonson, J.M.; Holmes, H.F.

1990-01-01

Electrochemical and electrical conductance cells have been widely used at ORNL over the years to quantitatively determine equilibrium constants and their salt effects to 300 degree C (EMF) and 800 degree C (conductance) at the saturation pressure of water (EMF) and to 4000 bars (conductance). The most precise results to 300 degree C for a large number of weak acids and bases show very similar thermodynamic behavior, which will be discussed. Results for the ionization constants of water, NH 3 (aq), HCl(aq), and NaCl(aq), which extend well into the supercritical region, have been fitted in terms of a model with dependence on density and temperature. The entropy change is found to be the driving force for ion-association reactions and this tendency increases (as it must) with increasing temperature at a given pressure. Also, the variation of all thermodynamic properties is greatly reduced at high fixed densities. Considerable variation occurs at low densities. From this analysis, the dependence of the reaction thermodynamics on the P-V-T properties of the solvent is shown, and the implication of large changes in hydration for solutes in the vicinity of the critical temperature will be discussed. Finally, the change in the molar compressibility coefficient for all reactions in water is shown to be the same and dependent only on the compressibility of the solvent

Structural and Thermodynamic Properties of the Argon Dimer: A Computational Chemistry Exercise in Quantum and Statistical Mechanics

Science.gov (United States)

Halpern, Arthur M.

2010-01-01

Using readily available computational applications and resources, students can construct a high-level ab initio potential energy surface (PES) for the argon dimer. From this information, they can obtain detailed molecular constants of the dimer, including its dissociation energy, which compare well with experimental determinations. Using both…

Extended thermodynamics

CERN Document Server

Müller, Ingo

1993-01-01

Physicists firmly believe that the differential equations of nature should be hyperbolic so as to exclude action at a distance; yet the equations of irreversible thermodynamics - those of Navier-Stokes and Fourier - are parabolic. This incompatibility between the expectation of physicists and the classical laws of thermodynamics has prompted the formulation of extended thermodynamics. After describing the motifs and early evolution of this new branch of irreversible thermodynamics, the authors apply the theory to mon-atomic gases, mixtures of gases, relativistic gases, and "gases" of phonons and photons. The discussion brings into perspective the various phenomena called second sound, such as heat propagation, propagation of shear stress and concentration, and the second sound in liquid helium. The formal mathematical structure of extended thermodynamics is exposed and the theory is shown to be fully compatible with the kinetic theory of gases. The study closes with the testing of extended thermodynamics thro...

Neurophysiological correlates of dissociative symptoms

NARCIS (Netherlands)

Kruijs, van der S.J.M.; Bodde, N.M.G; Carrette, E.C.B.; Lazeron, R.H.C; Vonck, K.E.J.; Boon, P.A.J.M.; Langereis, G.R.; Cluitmans, P.J.M.; Feijs, L.M.G.; Hofman, P.A.M.; Backes, W.H.; Jansen, J.F.A.; Aldenkamp, A.P.

2014-01-01

Objective: Dissociation is a mental process with psychological and somatoform manifestations, which is closely related to hypnotic suggestibility and essentially shows the ability to obtain distance from reality. An increased tendency to dissociate is a frequently reported characteristic of patients

Dissociation: a developmental psychoneurobiological perspective

African Journals Online (AJOL)

Adele

... the stream of con- sciousness and memory.1 It is a frequent symptom of a range ... infant for long time spans in an extremely disturbed psycho- biological state that ... Advantage: Dissociation is adaptive in the short-term. Dissociation can be ...

Correlations between electrochemical activity and heterogeneous catalysis for hydrogen dissociation on platinum

Energy Technology Data Exchange (ETDEWEB)

Ross, P N; Stonehart, P [Pratt and Whitney Aircraft, Middletown, Conn. (USA)

1975-02-01

Hydrogen-deuterium exchange rates on platinum surfaces have been compared to equivalent hydrogen molecule and adsorbed hydrogen atom electrochemical oxidation rates on the same surfaces. Over a temperature range of 293 to 360/sup 0/K the first order rate constants for H/sub 2/-D/sub 2/ exchange and hydrogen molecule electrochemical oxidation are the same, showing that the absorption-dissociation reaction (TAFEL, BONHOEFFER-FARKAS) is rate controlling. The rate of oxidation of the adsorbed hydrogen atom reaction involving electron transfer (VOLMER) is an order of magnitude larger.

Riemannian geometry of thermodynamics and systems with repulsive power-law interactions.

Science.gov (United States)

Ruppeiner, George

2005-07-01

A Riemannian geometric theory of thermodynamics based on the postulate that the curvature scalar R is proportional to the inverse free energy density is used to investigate three-dimensional fluid systems of identical classical point particles interacting with each other via a power-law potential energy gamma r(-alpha) . Such systems are useful in modeling melting transitions. The limit alpha-->infinity corresponds to the hard sphere gas. A thermodynamic limit exists only for short-range (alpha>3) and repulsive (gamma>0) interactions. The geometric theory solutions for given alpha>3 , gamma>0 , and any constant temperature T have the following properties: (1) the thermodynamics follows from a single function b (rho T(-3/alpha) ) , where rho is the density; (2) all solutions are equivalent up to a single scaling constant for rho T(-3/alpha) , related to gamma via the virial theorem; (3) at low density, solutions correspond to the ideal gas; (4) at high density there are solutions with pressure and energy depending on density as expected from solid state physics, though not with a Dulong-Petit heat capacity limit; (5) for 33.7913 a phase transition is required to go between these regimes; (7) for any alpha>3 we may include a first-order phase transition, which is expected from computer simulations; and (8) if alpha-->infinity, the density approaches a finite value as the pressure increases to infinity, with the pressure diverging logarithmically in the density difference.

Collision-induced dissociation of diatomic ions

International Nuclear Information System (INIS)

Los, J.; Govers, T.R.

1978-01-01

An attempt is made to illustrate how mass spectrometric studies of dissociation in diatomic molecular ions can provide information on the dynamics of these collisions and on the predissociative states involved. Restriction is made to primary beam energies of the order of at least keV. The review covers the dynamics of dissociation, experimental techniques, direct dissociation in heavy-particle collisions, and translational spectroscopy. 120 references

Boundary counterterms and the thermodynamics of 2-D black holes

International Nuclear Information System (INIS)

Davis, Joshua L.; McNees, Robert

2005-01-01

We utilize a novel method to study the thermodynamics of two dimensional type 0A black holes with constant RR flux. Our approach is based on the Hamilton-Jacobi method of deriving boundary counterterms. We demonstrate this approach by recovering the standard results for a well understood example, Witten's black hole. Between this example and the 0A black hole we find universal expressions for the entropy and black hole mass, as well as the infra-red divergence of the partition function. As a non-trivial check of our results we verify the first law of thermodynamics for these systems. Our results for the mass disagree with the predictions of a proposed matrix model dual of the 0A black hole

From state dissociation to status dissociatus.

Science.gov (United States)

Antelmi, Elena; Ferri, Raffaele; Iranzo, Alex; Arnulf, Isabelle; Dauvilliers, Yves; Bhatia, Kailash P; Liguori, Rocco; Schenck, Carlos H; Plazzi, Giuseppe

2016-08-01

The states of being are conventionally defined by the simultaneous occurrence of behavioral, neurophysiological and autonomic descriptors. State dissociation disorders are due to the intrusion of features typical of a different state into an ongoing state. Disorders related to these conditions are classified according to the ongoing main state and comprise: 1) Dissociation from prevailing wakefulness as seen in hypnagogic or hypnopompic hallucinations, automatic behaviors, sleep drunkenness, cataplexy and sleep paralysis 2) Dissociation from rapid eye movement (REM) sleep as seen in REM sleep behavior disorder and lucid dreaming and 3) Dissociation from NREM sleep as seen in the disorders of arousal. The extreme expression of states dissociation is characterized by the asynchronous occurrence of the various components of the different states that prevents the recognition of any state of being. This condition has been named status dissociatus. According to the underlying disorders/diseases and to their severity, among status dissociatus we may recognize disorders in which such an extreme dissociation occurs only at night time or intermittently (i.e., autoimmune encephalopathies, narcolepsy type 1 and IgLON5 parasomnia), and others in which it occurs nearly continuously with complete loss of any conventionally defined state of being, and of the circadian pattern (agrypnia excitata). Here, we render a comprehensive review of all diseases/disorders associated with state dissociation and status dissociatus and propose a critical classification of this complex scenario. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dissociation: Defining the Concept in Criminal Forensic Psychiatry.

Science.gov (United States)

Bourget, Dominique; Gagné, Pierre; Wood, Stephen Floyd

2017-06-01

Claims of amnesia and dissociative experiences in association with a violent crime are not uncommon. Research has shown that dissociation is a risk factor for violence and is seen most often in crimes of extreme violence. The subject matter is most relevant to forensic psychiatry. Peritraumatic dissociation for instance, with or without a history of dissociative disorder, is quite frequently reported by offenders presenting for a forensic psychiatric examination. Dissociation or dissociative amnesia for serious offenses can have legal repercussions stemming from their relevance to the legal constructs of fitness to stand trial, criminal responsibility, and diminished capacity. The complexity in forensic psychiatric assessments often lies in the difficulty of connecting clinical symptomatology reported by violent offenders to a specific condition included in the Diagnostic and Statistical Manual of Mental Disorders (DSM). This article provides a review of diagnostic considerations with regard to dissociation across the DSM nomenclature, with a focus on the main clinical constructs related to dissociation. Forensic implications are discussed, along with some guides for the forensic evaluator of offenders presenting with dissociation. © 2017 American Academy of Psychiatry and the Law.

Psychotherapy and Pharmacotherapy for Patients with Dissociative Identity Disorder

OpenAIRE

Gentile, Julie P.; Dillon, Kristy S.; Gillig, Paulette Marie

2013-01-01

There is a wide variety of what have been called “dissociative disorders,” including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma rep...

Irreversible thermodynamics, parabolic law and self-similar state in grain growth

International Nuclear Information System (INIS)

Rios, P.R.

2004-01-01

The formalism of the thermodynamic theory of irreversible processes is applied to grain growth to investigate the nature of the self-similar state and its corresponding parabolic law. Grain growth does not reach a steady state in the sense that the entropy production remains constant. However, the entropy production can be written as a product of two factors: a scale factor that tends to zero for long times and a scaled entropy production. It is suggested that the parabolic law and the self-similar state may be associated with the minimum of this scaled entropy production. This result implies that the parabolic law and the self-similar state have a sound irreversible thermodynamical basis

Energy distribution in dissociations of polyatomic molecules

International Nuclear Information System (INIS)

Koernig, S.A.

1989-01-01

In this thesis studies are reported of fragmentation processes in polyatomic molecules. In order to find out which dessocaciation reactions take place, how they are brought about by the internal energy of the reactant, and to investigate the structure of the dissociating 'transition state', the fragment mass and the corresponding kinetic energy release (KER) are determined by differential translational spectroscopy using a position and time sensitive two-particle coincidence detector. The results are interpreted using the statistical theory of unimolecular dissociation. It turns out that the standard assumptions of the theory, especially in calculating KER-distributions, are not realistic in all molecules considered. Dissociation is induced by the neutralization with alkali metal vapour. In ch. 2 the experimental method and the analysis of the data (dissociation pathways, branching ratios and ε-d-distributions) are introduced and exemplified by measurements of cyclohexane, which represents the upper limit in precursor and fragment mass accessible in the apparatus. In ch. 3 a study is reported of the molecules methylchloride (CH 3 Cl) and the acetylradical (CH 3 CO). In spite of their similar geometric structures, completely different dissociation mechanisms have been found. Methylchloride dissociates via a repulsive state; acetyl radicals show energy scrambling. The energy distribution from dissociating acetyl exemplifies dynamical effects in the dissociation. In ch. 4 an investigation of a number of prototype hydrocarbons is presented. The dissociation pathways of several small linear alkanes indicate that neutralization takes place to unknown repulsive potentials, of which the position and steepness are determined from the kinetic energy release. (author). 118 refs.; 40 figs.; 5 tabs

Dissociative depression among women in the community.

Science.gov (United States)

Sar, Vedat; Akyüz, Gamze; Oztürk, Erdinç; Alioğlu, Firdevs

2013-01-01

This study screened the prevalence and correlates of dissociative disorders among depressive women in the general population. The Dissociative Disorders Interview Schedule and the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interview for DSM-IV were administered to 628 women in 500 homes. The prevalence of current major depressive episode was 10.0%. Of the women, 26 (40.6%) had the lifetime diagnosis of a DSM-IV, dissociative disorder, yielding a prevalence of 4.1% for dissociative depression. This group was younger (mean age = 30.7 years) than the nondissociative depression women (mean age = 39.6 years). There was no difference between the 2 groups on comorbid somatization disorder, PTSD, or borderline personality disorder. Besides suicide attempts, the dissociative group was characterized by secondary features of dissociative identity disorder; Schneiderian symptoms; borderline personality disorder criteria; and extrasensory perceptions, including possession experiences. They reported suicidality, thoughts of guilt and worthlessness, diminished concentration and indecisiveness, and appetite and weight changes more frequently than the nondissociative group. Early cessation of school education and childhood sexual abuse were frequently reported by the dissociative depression group. With its distinct features, the concept of dissociative depression may facilitate understanding of treatment resistance in, development of better psychotherapy strategies for, and new thinking on the neurobiology and pharmacotherapy of depressive disorders.

Carrying out thermodynamic calculations and definition of the main reactions of decomposition of vapours of ethyl alcohol

International Nuclear Information System (INIS)

Sechin, A I; Kyrmakova, O S; Ivanova, T A

2015-01-01

Thermodynamic opportunities of course of chemical reactions of decomposition of the vapors of ethyl alcohol necessary at development of devices where these reactions will take place are considered. The entalpiyny method of calculation of constants of balance of probable chemical reactions is given in the Excel editor. Independent reactions of process of oxidation are defined. By result of thermodynamic calculation of each reaction schedules of dependence of a constant of balance on environment temperature from which follows are constructed that one reactions proceed until the end of aside formation of the final products, and others are improbable or impossible. The analysis of the received results shows that reactions of oxidation will successfully proceed in the established directions, and for an intensification of process of decomposition it is necessary to provide a supply of some energy which quantity will be sufficient for oxidation of vapors of ethyl alcohol. Results of calculations showed good convergence with programs of thermodynamic calculations like 'Aster - 4' and 'TERRA'. (paper)

Duality in diffraction dissociations

International Nuclear Information System (INIS)

Santoro, Alberto.

1977-01-01

Diffractive dissociations (aN→a*πN) are naturally explained and a model that accounts for the three-variable correlation (mass-transfer-Jackson angle correlation) is presented. This model takes into account the three possible exchanges: t (pion), u(a*) and s(a) channel exchanger. The physical consequences of the model are: a strong mass-slope correlation due to the zeros of the amplitude, a factorization of diffractive dissociations (factorization of the Pomeron), the possibility of extending this model to double diffractive dissociation and diffraction by nuclei. This model was applied to the NN→NπN reaction. Using the usual parameters of the Deck model, a comparison is made with experiments for all available distributions. the strong slope of the peak at 1400 MeV is naturally explained [fr

Constant-pH molecular dynamics using stochastic titration

Science.gov (United States)

Baptista, António M.; Teixeira, Vitor H.; Soares, Cláudio M.

2002-09-01

A new method is proposed for performing constant-pH molecular dynamics (MD) simulations, that is, MD simulations where pH is one of the external thermodynamic parameters, like the temperature or the pressure. The protonation state of each titrable site in the solute is allowed to change during a molecular mechanics (MM) MD simulation, the new states being obtained from a combination of continuum electrostatics (CE) calculations and Monte Carlo (MC) simulation of protonation equilibrium. The coupling between the MM/MD and CE/MC algorithms is done in a way that ensures a proper Markov chain, sampling from the intended semigrand canonical distribution. This stochastic titration method is applied to succinic acid, aimed at illustrating the method and examining the choice of its adjustable parameters. The complete titration of succinic acid, using constant-pH MD simulations at different pH values, gives a clear picture of the coupling between the trans/gauche isomerization and the protonation process, making it possible to reconcile some apparently contradictory results of previous studies. The present constant-pH MD method is shown to require a moderate increase of computational cost when compared to the usual MD method.

Effects of chemical structure on the thermodynamic efficiency of radical chain carriers for organic synthesis.

Science.gov (United States)

Lin, Ching Yeh; Peh, Jessie; Coote, Michelle L

2011-03-18

The chain carrier index (CCI), defined as the ratio of the bond dissociation free energies (BDFE) of corresponding chain carrier halides and hydrides, is proposed as a measure of the thermodynamic efficiency of chain carriers for radical dehalogenation. The larger this value is relative to the corresponding value of the organic substrate, the more thermodynamically efficient the process. The chloride and bromide CCIs were evaluated at the G3(MP2)-RAD(+) level of theory for 120 different R-groups, covering a broad range of carbon-centered and noncarbon-centered species; the effects of solvent and temperature have also been studied. The broad finding from this work is that successful chain carriers generally maximize the strength of their halide (versus hydride bonds) through charge-shift bonding. As a result, the thermodynamic efficiency of a chain carrier tends to increase down the periodic table, and also with the inclusion of stronger electron donating substituents. The CCIs of carbon-centered species fall into a relatively narrow range so that, even when the CCI is maximized through inclusion of lone pair donor OMe or NMe(2) groups, the thermodynamic driving force for dehalogenation of other organic substrates is modest at best, and the process is likely to be kinetically hampered. Among the noncarbon-centered species studied, bismuth- and borane-centered compounds have some of the highest CCI values and, although their kinetics requires further optimization, these classes of compounds would be worth further investigation as tin-free radical reducing agents.

Dissociative Functions in the Normal Mourning Process.

Science.gov (United States)

Kauffman, Jeffrey

1994-01-01

Sees dissociative functions in mourning process as occurring in conjunction with integrative trends. Considers initial shock reaction in mourning as model of normal dissociation in mourning process. Dissociation is understood to be related to traumatic significance of death in human consciousness. Discerns four psychological categories of…