On guessing the realization of an arbitrarily varying source

We present a method to guess the realization of an arbitrarily varying source. Let TU be the type of the unknown state sequence. Our method results in a guessing moment that is within Kn (TU) + O(log n=n) of the minimum attainable guessing moment with full knowledge of source statistics, i.e., with knowledge of the sequence of states sn. The quantity Kn (TU) + O(log n=n) can be interpreted as the penalty one pays for not knowing the sequence of states sn of the source. Kn (TU) by itself is the penalty one pays for guessing with the additional knowledge that the state sequence belongs to type TU. Conversely, given any guessing strategy, for every type TU, there is a state sequence belonging to this type whose corresponding source forces a guessing moment penalty of at least Kn (TU) ¡ O(log n=n).

Brillouin Scattering Investigation of Solvation Dynamics in Succinonitrile-Lithium Salt Plastic Crystalline Electrolytes

Temperature dependent Brillouin scattering studies have been performed to ascertain the influence of solvent dynamics on ion-transport in succinonitrile-lithium salt plastic crystalline electrolytes. Though very rarely employed, we observe that Brillouin spectroscopy is an invaluable tool for investigation of solvent dynamics. Analysis of various acoustic (long wavelength) phonon modes observed in the Brillouin scattering spectra reveal the influence of trans-gauche isomerism and as well as ion-association effects on ion transport. Although pristine SN and dilute SN-LiClO(4) samples show only the bulk longitudinal-acoustic (LA) mode, concentrated SN-LiClO(4) (similar to 0.3-1 M) electrolytes display both the bulk LA mode as well as salt induced brillouin modes at ambient temperature. The appearance of more than one brillouin mode is attributed to the scattering of light from regions with different compressibilities (''compactness''). Correspondingly, these modes show a large decrease in the full width at half-maximum (abbreviated as nu(f)) as the temperature decreases. Anomalous temperature dependent behavior of nu(f) with addition of salt could be attributed to the presence of disorder or strong coupling with a neighbor. The shape of the spectrum was evaluated using a Lorentzian and Fano line shape function depending on the nature and behavior of the Brillouin modes.

Thermodynamics of oxygen in liquid copper-tin alloys

The activity coefficients of oxygen in copper-tin alloys at 1 1 00°C have been measured by two different equilibrium methodsthe cell Pt, Ni + NiO I ZrOz solid electrolyte I O[Cu + Sn], cermet. Pt and the equilibrium between Cu + Sn alloys and SnO + SiO, slags established via SnO vapour. The results from both types of measurement confirm the work of Block and co-workers and show that other data are in error. The deoxidation equilibria for Sn in liquid copper, with solid SnO, as deoxidation product, have been evaluated at temperatures of interest in copper smelting.

Thermodynamic study of oxygen in liquid lead tin alloys

The activity coefficients of oxygen in liquid lead-tin alloys have been measured between 550 and 1100°C by use of solid oxide galvanic cells Pt, Ni-NiO I Zr02 Solid electrolyte I 0 (Pb + Sn), Cermet, Pt Pt, Fe-FeO I Zr02 Solid electrolyte I O(Pb + Sn), Cermet, Pt Alcock and Richardson's quasi-chemical equation, with the coordination number of atoms set to 2, is found to predict successfully the activity coefficients of oxygen in these alloys.The relative partial molar enthalpy and entropy of oxygen ?t 1 atom per cent in the alloys have been calculated from ttva variation of the activity coefficient with temperature. The addition of tin to an unsaturated solution of oxygen in lead is shown to decrease significantly both the partial molar enthalpy and entropy of oxygen. As the measurements were restricted to a narrow range between 750-1100'C in lead-rich alloys, however, the pronounced variation of the partial molar enthalpy of oxygen with temperature at constant alloy composition predicted by the quasi-chemical model could not be verified.

Prediction of activities of oxygen in dilute quaternary solutions using binary data

Equations are developed for predicting the activity coefficients of oxygen dissolved in ternary liquid alloys. These are extensions of earlier treatments, and are based on a model in which each oxygen atom is assumed to make four bonds with neighboring metal atoms. It is also postulated that the strong oxygen-metal bonds distort the electronic configuration around the metal atoms bonded to oxygen, and that the quantitative reduction of the strength of bonds made by these atoms with all of the adjacent metal atoms is equivalent to a factor of approximately two. The predictions of the quasichemical equation which is derived agree satisfactorily with the partial molar free energies of oxygen in Ag-Cu-Sn solutions at 1200°C reported in literature. An extension of this treatment to multicomponent solutions is also indicated.

Electrochemical Determination of the Stability of Mono- and Dicalcium Stannates

he thermodynamic properties of mono- and dicalcium stannates have been determined in the temperature range 973–-1423°K from the electromotive force measurements on solid oxide galvanic cells[dformula Pt, Ni + NiO//CaO - ZrO[sub 2]/Y[sub 2]0[sub 3] - ThO[sub 2]//SnO[sub 2] + Sn, W, Pt][dformula Pt, Ni + NiO//CaO - ZrO[sub 2]/Y[sub 2]O[sub 3] - ThO[sub 2]//CaSnO[sub 3] + SnO[sub 2] + Sn, W, Pt][dformula Pt, Ni + NiO//CaO - ZrO[sub 2]/Y[sub 2]O[sub 3] - ThO[sub 2]/Ca[sub 2]SnO[sub 4] + CaSnO[sub 3] + Sn, W, Pt]and [dformula Pt, Ni + NiO//CaO - ZrO[sub 2]sol;Y[sub 2]O[sub 3] - ThO[sub 2]//Ca[sub 2]SnO[sub 4] + CaO, W, Pt] The Gibbs free energy changes accompanying the formation of the stannates from component oxides may be represented by the equations[dformula 2CaO + SnO[sub 2] --> Ca[sub 2]SnO[sub 4]][dformula Delta G[degree] = - 17,040 + 0.85T ([plus-minus]300) cal][dformula CaO + SnO[sub 2] --> CaSnO[sub 3]][dformula Delta G[degree] = - 17,390 + 2.0T ([plus-minus]300) cal]The partial pressures of the tin bearing oxide species resulting from the decomposition of the stannates have been calculated as a function of the oxygen partial pressure by combining the results of this study with published information on the partial pressures and composition of oxide species over stannic oxide.

Pickup and delivery problem using metaheuristics techniques

Dial-a-ride problem (DARP) is an optimization problem which deals with the minimization of the cost of the provided service where the customers are provided a door-to-door service based on their requests. This optimization model presented in earlier studies, is considered in this study. Due to the non-linear nature of the objective function the traditional optimization methods are plagued with the problem of converging to a local minima. To overcome this pitfall we use metaheuristics namely Simulated Annealing (SA), Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Artificial Immune System (AIS). From the results obtained, we conclude that Artificial Immune System method effectively tackles this optimization problem by providing us with optimal solutions. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.

Current views on microscopic thermodynamics of liquid alloys

An attempt has been made to review current information on the microscopic thermodynamics of liquid alloys. For complex alloys, and for alloys of simple metals with strong "compound-forming" tendencies, the fluctuation approach developed by Bhatia and his co-workers provides a useful link between the fluctuation in concentration and number density of atoms in the mixture on the one hand, and macroscopic thermodynamic properties on the other. Some selected examples of the application of structural data of liquid alloys to estimating macroscopic thermodynamic properties such as the Gibbs free energy of mixing, coupled with the fluctuation approach are given. The relevant thermodynamic quantities such as vapor pressure and entropy are also discussed, to facilitate the understanding of the present status of the fundamental and powerful links between macroscopic and microscopic (atomic scale) structure of liquid alloys (Mg--Sn, Li--Pb, Hg--K). 63 ref.--AA