EXCESS GIBBS ENERGY FOR THE BINARY MIXTURES OF NITROBENZENE WITH SOME HYDROCARBONS AT 94.95 KPA

Bubble point temperatures at 94.95 kPa, over the entire composition range, are measured for the binary mixtures of nitrobenzene with: cyclohexane, n-hexane, n-heptane, n-decane, and o-, m-, and p-xylenes, using a Swietoslawski-type ebulliometer. Liquid phase composition versus bubble point temperature measurements are well represented by the Wilson model. Computed values of the excess Gibbs energy are presented and discussed.     

REACTIVE EXTRACTION OF LEVULINIC ACID FROM AQUEOUS SOLUTIONS WITH TRI-n-OCTYLAMINE (TOA) IN 1-OCTANOL: EQUILIBRIA,KINETICS, AND MODEL DEVELOPMENT

Levulinic acid, a carboxylic acid containing a ketone structure, can be used as an acidulant in foods and beverages. Reactive extraction is a promising alternative for the recovery of carboxylic acids from aqueous streams. The design of an amine extraction process requires kinetic data for the acid-amine + solvent system used. In this study, equilibrium and kinetic data on the extraction of levulinic acid from aqueous solutions using tri-n-octylamine (TOA) in 1-octanol have been determined. The mass transfer coefficients of levulinic acid, TOA, and 2:1 levulinic acid-amine complex in 1-octanol were calculated from the acetic acid mass transfer coefficient, which was determined by measuring its fluxes of simple diffusion from kerosene to water. Based on the Hatta number and the criterion given by Doraiswamy and Sharma, the reaction regime has been found to be instantaneous reaction regime occurring at the interface on the organic phase side. An extraction model comprising equilibrium complexation constant w.r.t 2:1 levulinic acid-TOA complex formation, K_E2i (14.794 (m³ kmol^?1)²), and complex mass transfer coefficient, k_B2A (2.193 × 10^?6 m s^?1), has been developed.     

Irreversibility analysis of micropolar nanofluid flow in a vertical channel with the impact of inclined magnetic field and heat source or sink

This article examines the inclined magnetic field effect on the flow of micropolar nanofluids in a vertical channel with convective boundary conditions and heat source or sink. Thermodynamics second law is employed to analyze the aspects of entropy generation. The governing differential equations are modified into dimensionless form by using suitable nondimensional variables. These transformed equations are solved by implementing the differential transform technique. The results are analyzed graphically. Skin friction and Nusselt number values are evaluated at the boundary walls of the channel. The major findings of the study are material parameter enhances the microrotation but suppresses both velocity and temperature. Magnetic parameter and angle of the implication of magnetic field decrease the velocity and microrotation. Material parameter and angle of imposed magnetic field minimize the entropy generation.     

IPv6 integration and coexistence strategies for next-generation networks

IPv6 has been designed, among other things, to provide an expanded address space to satisfy the future networking requirements. In this article, we analyze and discuss important aspects of IPv6 deployment scenarios, and propose the system architecture coexisting and integrating with IPv4/MPLS networks. We investigate on various IPv6 deployment strategies along with network design examples, comparing these techniques. Then the IPv6 deployment in service provider environments is proposed.     

Corner based statistical modelling in vehicle detection under various condition for traffic surveillance

The paper proposes a robust approach to detect and track the vehicle under various climatic conditions and in the presence of camera shake, shadows, sudden illumination change. Corners have significant features to detect and track the vehicle. Corner points from the vehicular region are segmented from non - vehicular regions based on the statistical background corner point model. The foreground corner points that belong to the vehicular region are grouped using Euclidean distance as they are closely associated with each other. The flickering effects caused by the corner detection algorithm are handled by tracking these corner points. The detection accuracy of the algorithm is 94.32%.

     

A comprehensive single‐particle model for solid‐state polymerization of poly(L‐lactic acid)

We propose here, a comprehensive model for the solid‐state polymerization (SSP) of a low to moderate molecular weight (MW) prepolymer of lactic acid, to produce high MW poly(L ‐lactic acid) (PLLA). The reactions are rationally assumed to occur only in the amorphous region, and effective concentrations of end groups, vary with crystalinity, X_c, during SSP. We estimate byproduct diffusivities, D, using free volume theory. The effects of various parameters on the SSP of PLLA prepolymer have been examined with respect to the optimum MW, X_c and D. We introduce self‐consistently, scaling factors of ～ 0.27, in the experimental procedure, to determine via ¹⁹F‐NMR, concentrations of the end groups, after converting them to fluorinated ester groups. The relevant reaction rate constants are obtained by fitting to early time data from representative SSP experiments at 150°C, under high vacuum, on PLLA prepolymer powder (i.e., spherical geometry) of number average MW, M_n0 ～ 10,200 Da, which attains M_n ～ 150,000 Da, via SSP. The subsequent successful comparison of the model predictions with experimental data throughout the entire SSP duration indicates that the model is comprehensive and accounts for all the relevant phenomena occurring during the SSP to synthesize high MW PLLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011