NOPR Collection:

Molecular interaction of aspartic acid in aqueous metal chloride solution — Volumetric, viscometric, acoustical and optical studies

2016-07-20T05:41:22Z

Title: Molecular interaction of aspartic acid in aqueous metal chloride solution — Volumetric, viscometric, acoustical and optical studies Authors: Umaley, K D; Aswar, A S Abstract: Measurements of density, viscosity, ultrasonic velocity and refractive index of L-aspartic acid (0.01-0.09 mol.L^-1) in 0.1 M, 0.05 M and 0.025 M aqueous zinc chloride and copper chloride solutions have been carried out at 308.15 K to evaluate some important parameters, viz. isentropic compressibility, relative association, free path length, apparent molar volume, apparent molar isentropic compressibility and molar refraction. These values are used to explain molecular association, solute-solvent interaction through hydrogen bonding and solvation. Viscosity data have been analyzed in the light of Jones-Dole equation and the constants A and B are estimated. The results have been interpreted in the light of various interactions occurring between components of the mixtures under applied experimental conditions. The aspartic acid has been found to be structure maker in aqueous zinc chloride and copper chloride solutions from molar volume and as well as viscosity data. Page(s): 295-302

Efficient and reliable tuning techniques for PI-controller in a chemical pH process

2016-07-20T05:40:19Z

Title: Efficient and reliable tuning techniques for PI-controller in a chemical pH process Authors: Saji, K S; Kumar, M Sasi Abstract: A control strategy based on tuning of a PI-controller with fuzzy sliding mode control, simulated annealing and particle swarm optimization has been implemented for a pH process. A fuzzy sliding-mode control is designed to enhance the robustness of system and to reduce the influence of time-varying disturbances. The study also includes simulated annealing to find out the global optimum solution. Simulated annealing has less reliability to fail on difficult functions because of its robustness. Hence, an efficient and reliable swarm intelligence-based approach, namely particle swarm optimization technique, to optimize the proportional and integral gains is also used. The simulation results show that the proposed controller outperforms the classical tuning in stability, convergence and robustness. The results obtained by various tuning algorithms are also described. Page(s): 289-294

Digital conductometry for determination of boron in light water and heavy water at trace levels

2016-07-20T05:39:08Z

Title: Digital conductometry for determination of boron in light water and heavy water at trace levels Authors: Ananthanarayanan, R; Sahoo, P; Murali, N Abstract: In-house built PC based rapid conductometric titration method for assay of trace amount of boron in light water and heavy water [100 ppb (µg L^-1)] with a precision of 2.2 has been reported. The method involves conversion of trace quantity of extremely poor conducting boric acid present in the sample to a relatively better conducting complexing species boron-mannitol complex using mannitol. This complex is then titrated against NaOH. Minor shift in conductivity during reaction of the complex compound with NaOH is captured online using an indigenously developed high resolution conductometric titration device. In addition, the technique provides information about any reactive chemical specimens, if present in the sample. The entire titration process is completed within a couple of minutes. A high resolution conductivity measurement technique has been proposed for quick assay of boron down to 20 ppbB level (RSD 4.1%). The present technique is suitable for rapid assay of boron in heavy water moderator in pressurised heavy water reactors. The influence of isotopic effect on sensitivity of measurements of boron in light water and heavy water matrices is also described. Page(s): 278-288

Synthesis and characterization of soluble and transparent co-polyimides with controlled glass transition temperature

2016-07-20T05:38:02Z

Title: Synthesis and characterization of soluble and transparent co-polyimides with controlled glass transition temperature Authors: Tian, Xiuzhi; Jiang, Xue; Lu, Hui; Huang, Dan Abstract: Two dianhydrides, namely 4,4'-oxydiphthalic dianhydride and 2,2’-Bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride, and one diamine (4,4’-Diaminodiphenyl sulphone), have been used for the synthesis of a novel co-polyimide with good solubility, high visible light transparency and high thermal stability. The solubility in several solvents of polyimides with different proportion of dianhydrides has been tested, and the glass transition temperature is determined by differential scanning calorimetry. The polyimide film has been prepared and the optical transmittance is mensurated. The polyimides solubility and light transmittance improved by introducing flexible monomer, and the glass transition temperature of the polyimides is well controlled by the content of 2,2’-Bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride that has the flexible isopropylidene structure. Page(s): 271-277