On the Temperature of a Rarefied Gas in Non‐Equilibrium

This paper addresses the problem of the proper definition of temperature of a gas in nonequilibrium. It shows that the mean kinetic energy of the atoms of a rarefied gas is not a good measure for thethermodynamic temperature, because in general it jumps at a wall, and because it is nonmonotone in a onedimensional process of stationary heat conduction. The jump of the kinetic temperature is calculated and found to be about 5K in a rarefied gas. The basis for the calculations is provided by the arguments of extended thermodynamics of 14 moments. An essential tool is the minimax principle of entropy production recently postulated by Struchtrup Weiss [1], because it furnishes one important boundary condition.Sommario. Il lavoro riguarda la corretta definizione della temperatura di un gas in condizioni di nonequilibrio. Si mostra come lenergia cinetica media degli atomi di un gas rarefatto non sia una buona misura della temperatura termodinamica poiché in generale, essa risulta discontinua su una parete e nonmonotona in un processo unidimensionale di conduzione stazionaria del calore. Viene calcolato il salto della temperatura cinetica che risulta pari a circa 5K in un gas rarefatto. La base per il calcolo è fornita dal contesto della termodinamica estesa di 14 momenti. Uno strumento essenziale è rappresentato dal principio di minimax di produzione di entropia recentemente postulato da Struchtrup and Weiss [1], che fornisce unimportante condizione alcontorno.     

FEM-FDM coupled liquefaction analysis of a porous soil using an elasto-plastic model

The phenomenon of liquefaction is one of the most important subjects in Earthquake Engineering and Coastal Engineering. In the present study, the governing equations of such coupling problems as soil skeleton and pore water are obtained through application of the two-phase mixture theory. Using au-p (displacement of the solid phase-pore water pressure) formulation, a simple and practical numerical method for the liquefaction analysis is formulated. The finite difference method (FDM) is used for the spatial discretization of the continuity equation to define the pore water pressure at the center of the element, while the finite element method (FEM) is used for the spatial discretization of the equilibrium equation. FEM-FDM coupled analysis succeeds in reducing the degrees of freedom in the descretized equations. The accuracy of the proposed numerical method is addressed through a comparison of the numerical results and the analytical solutions for the transient response of saturated porous solids. An elasto-plastic constitutive model based on the non-linear kinematic hardening rule is formulated to describe the stress-strain behavior of granular materials under cyclic loading. Finally, the applicability of the proposed numerical method is examined. The following two numerical examples are analyzed in this study: (1) the behavior of seabed deposits under wave action, and (2) a numerical simulation of shaking table test of coal fly ash deposit.     

Molecular extended thermodynamics: comparison between rarefied polyatomic and monatomic gas closures

Molecular extended thermodynamics is justified at the mesoscopic level by the moment equations associated with the Boltzmann equation. For polyatomic gases we have a binary hierarchy of moments in contrast with the usual single hierarchy for monatomic gases. In this paper, taking one-dimensional space variables for simplicity, we review the closure of the system of the moment equations for polyatomic gases with the use of the maximum entropy principle, which is equivalent to the entropy principle. Then we consider the singular limit where the degrees of freedom of a molecule approach 3, and we prove that, by imposing appropriate initial conditions, the solutions for polyatomic gases converge to the ones for monatomic gases. As examples of the singular limit, the asymptotic behaviors of linear waves and light scattering based on the linearized system of field equations are briefly presented.     

Asymptotic distribution of the LR statistic for equality of the smallest eigenvalues in high-dimensional principal component analysis

This paper deals with the distribution of the LR statistic for testing the hypothesis that the smallest eigenvalues of a covariance matrix are equal. We derive an asymptotic null distribution of the LR statistic when the dimension p and the sample size N approach infinity, while the ratio p/N converging on a finite nonzero limit c(0,1). Numerical simulations revealed that our approximation is more accurate than the classical chi-square-type approximation as p increases in value.     

Electron-phonon interaction and localization of surface-state carriers in a metallic monolayer

Temperature-dependent electron transport in a metallic surface superstructure, Si(111)sqrt[3] x sqrt[3]-Ag, was studied by a micro-four-point probe method and photoemission spectroscopy. The surface-state conductivity exhibits a sharp transition from metallic conduction to strong localization at approximately 150 K. The metallic regime is due to electron-phonon interaction while the localization seemingly originates from coherency of electron waves. Random potential variations, caused by Friedel oscillations of surface electrons around defects, likely induce strong carrier localization.     

Synthesis and structure activity relationship studies of benzothieno[3,2-b]furan derivatives as a novel class of IKKbeta inhibitors

As a novel class of IKKbeta inhibitors, a series of tricyclic furan derivatives was designed and synthesized based on the structure of known thiophene IKKbeta inhibitors. Among the various fused furan derivatives synthesized, a benzothieno[3,2-b]furan derivative 13a displayed potent inhibitory activity towards IKKbeta in enzymatic and cellular assays. The potent inhibitory activity originates from an intramolecular non-bonded S...O interaction which was confirmed by the X-ray structure of JNK3 with 16k. The introduction of further substituents on the core structure led to the discovery of the 6-alkoxy derivatives, which possessed a comparable IKKbeta inhibitory activity to 13a and an improved metabolic stability. Among these, appropriately lipophilic compounds 16a, h, i, and 13g (log D>2) were found to possess good oral bioavailability.     

Cinchona alkaloids/TMAF combination-catalyzed nucleophilic enantioselective trifluoromethylation of aryl ketones

The catalytic, nucleophilic enantioselective trifluoromethylation reaction of both acyclic and cyclic aryl ketones using the Ruppert-Prakash reagent is now at hand, with an operationally simple procedure, based on the combination of ammonium bromide of cinchona alkaloids with TMAF. The procedure is reliable and general. Trifluoromethyl-substituted tetrasubstituted aryl alcohols have been synthesized in up to 94% ee.     

Strategies for Sensitive and Selective Determination of Metal Ions by Ion-pair Reversed-phase HPLC

The ability of reversed-phase high performance liquid chromatography (RP-HPLC) has led to its widespread use in the determination of trace metal ions. The object of this study was to develop a superior ion-pair (IP) -RP-HPLC for charged metal chelates, with particular interest in injection solvent and mobile phase composition containing counterion.