Conductive wool yarns by continuous vapour phase polymerization of pyrrole

Conducting polypyrrole (PPy) coated wool yarns were prepared by a continuous vapour polymerization technique, using a speed of 1 m/min with different iron(III) chloride (FeCl₃) as the oxidant at different concentrations. The resistivities, tensile properties, longitudinal and cross-sectional views of PPy-coated wool yarns were investigated. Optimum specific electrical resistances of 2.96 Ω g/cm² at 80 g/L FeCl₃ and 1.69 Ω g/cm² at 70 g/L FeCl₃ were obtained for 500 and 400 twist per meter (TPM) yarns, respectively. PPy-coated wool yarns exhibited higher elongation than uncoated yarns. Longitudinal and cross-sectional views of the yarns indicate that PPy coating penetrated deep into the yarn cross-section and a uniform coating was obtained on the surface of the yarn surface.     

Interaction of phenol with isoprene cyclodimers in the presence of zeolite Y impregnated with orthophosphoric acid

Results of examining the reaction of phenol with diprene, dipentene, and the isoprene cyclodimer fraction using orthophosphoric acid-impregnated zeolite Y as a catalyst in a continuous processing unit are presented. Optimal conditions for the synthesis of p-cycloalkylphenols have been found. It has been shown that under the optimal conditions, the yield of target p-cycloalkylphenols is 72.3?C75.6% and the selectivity is 91.6?C95.7%.     

Investigation of possibility of developing high-efficiency heat-conducting system of electrical insulation for turbo generators with air and hydrogen cooling

The results of comparative tests of the main electrophysical properties of a new type of high-efficiency heat-conducting insulation for turbo generators with air and hydrogen cooling as compared to the traditional insulation are presented. It is shown that the addition of modified varnish with a high thermal conductivity coefficient to the insulation material does not yield any deterioration of its electrical properties.     

Electrical,electrochemical and photo-electrochemical studies on the electrodeposited n-type semiconductor hexagonal crystalline CdS thin film on nickel substrate

Electrodeposited cadmium sulfide (CdS) on nickel substrate of new properties from aqueous solutions of Cd²⁺ and S₂O₃ ^2? at 313 K has been obtained using cyclic voltammetric and potentiostatic techniques. The mechanism of the electrode reactions for the electrodeposition of CdS has been evaluated and proposed. Energy dispersive X-ray florescence elemental analysis and X-ray diffraction investigations demonstrate that, the electrodeposited CdS is pure and hexagonal polycrystalline in nature, at our optimal conditions. Furthermore, the electrodeposited CdS is of n-type semiconductor was investigated and confirmed by Mott–Schotky test. Donor concentration (N_D) was determined to be 1.0 × 10¹⁷ cm^?3. In this research we discovered that, the electrodeposited semiconductor CdS on Ni substrate has low resistivity and magnetic properties (became as a strong magnet) at the mentioned conditions. The photoelectrochemical measurements of the electrodeposited CdS on nickel electrode had been investigated at room temperature and under illumination giving good results.     

Structural basis of biological nitrogen fixation

Biological nitrogen fixation is mediated by the nitrogenase enzyme system that catalyses the ATP dependent reduction of atmospheric dinitrogen to ammonia. Nitrogenase consists of two component metalloproteins, the MoFe-protein with the FeMo-cofactor that provides the active site for substrate reduction, and the Fe-protein that couples ATP hydrolysis to electron transfer. An overview of the nitrogenase system is presented that emphasizes the structural organization of the proteins and associated metalloclusters that have the remarkable ability to catalyse nitrogen fixation under ambient conditions. Although the mechanism of ammonia formation by nitrogenase remains enigmatic, mechanistic inferences motivated by recent developments in the areas of nitrogenase biochemistry, spectroscopy, model chemistry and computational studies are discussed within this structural framework.     

Lagrangean-based solution approaches for the generalized problem of locating capacitated warehouses

The traditional capacitated warehouse location problem consists of determining the number and the location of capacitated warehouses on a predefined set of potential sites such that the demands of a set of customers are met. A very common assumption made in modeling this problem in almost all of the existing research is that the total capacity of all potential warehouses is sufficient to meet the total demand. Whereas this assumption facilitates to define a well‐structured problem from the mathematical modeling perspective, it is in fact restrictive, not realistic, and hence rarely held in practice. The modeling approach presented in this paper breaks away from the existing research in relaxing this very restrictive assumption. This paper therefore investigates the generalized problem of locating warehouses in a supply chain setting with multiple commodities with no restriction on the total capacity and the demand. A new integer programming formulation for this problem is presented, and an algorithm based on Lagrangean relaxation and decomposition is described for its solution. Three Lagrangean heuristics are proposed. Computational results indicate that reasonably good solutions can be obtained with the proposed algorithms, without having to use a general purpose optimizer.     

Experimental and numerical study on charging processes of an ice‐on‐coil thermal energy storage system

In this study, an external melt ice‐on‐coil thermal storage was studied and tested over various inlet conditions of secondary fluid—glycol solution—flow rate and temperature in charging process. Experiments were conducted to investigate the effect of inlet conditions of secondary fluid and validate the numerical model predictions on ice‐on‐coil thermal energy storage system. The total thermal storage energy and the heat transfer rate in the system were investigated in the range of 10 l min ^?1?V??60 l min ^?1. A new numerical model based on temperature transforming method for phase change material (PCM) described by Faghri was developed to solve the problem of the system consisting of governing equations for the heat transfer fluid, pipe wall and PCM. Numerical simulations were performed to investigate the effect of working conditions of secondary fluid and these were compared with the experimental results. The numerical results verified with experimental investigation show that the stored energy rises with increasing flow rate a decreasing tendency. It is also observed that the inlet temperature of the fluid has more influence on energy storage quantity than flow rate. Copyright © 2006 John Wiley & Sons, Ltd.