Synthesis and characterization of conducting polymer composites based on polyaniline–polyethylene glycol–zinc sulfide system

Hybrid semiconducting polymer composites containing polyaniline, polyethylene glycol and zinc sulfide have been prepared in various combinations by in-situ polymerization of aniline using ammonium per disulfate in acidic medium. A biomimetic approach of controlled precipitation has been used. A mechanism of formation of these hybrid materials has been suggested in which polyethylene glycol works as a medium for diffusion-limited growth of various components during their precipitation. These materials have been characterized by a variety of spectroscopic techniques, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and alternating current impedance spectroscopy. Equivalent circuits for different contributions from grain, grain boundary and electrode for different systems have been determined with the help of complex non-linear least square analysis software. The microstructure-property correlation have been discussed along with the possible conduction mechanisms from the temperature dependence of conductivity as variable-dimension variable-range hopping for different compositions of single, double and triple composite materials.     

当极简嵌入历史

雅法,是世界上最古老的城市之一,有4000多年的历史,面临地中海。项目中的这座古宅就坐落在这座曾经辉煌的城市中,它庄严辉煌的开口也同样正面对着地中海,可以俯瞰整个海面。虽然我们现在已经很难确定建筑确切年纪,不过很清楚的是,它已有上百年的历史了。     

A production-recycling-inventory model with learning effect

This paper develops an integrated production-recycling system over a finite time horizon. Here, the dynamic demand is satisfied by production and recycling. The used units are bought back and then either recycled or disposed of which are not repairable. The used units are collected continuously from the customers. Recycling products can be used as new products which are sold again. The rate of production and disposal are assumed to be function of time. The setup cost is reduced over time due to “Learning curve” effect. The optimum results are presented both in tabular form and graphically.     

Development of Breathing Rat-Lung Models for Particulate Deposition Studies

ABSTRACT

Techniques have been developed for casting both solid and hollow lung models from rat-lung specimens. To make a solid model, an air line at a positive pressure of 25 cm of water was connected to the trachea to air-dry lungs which had been removed surgically from the animal. Using the lost wax technique, a hollow cast of the airways and the nasopharynx was made. A mechanical breathing system, capable of simulating different breathing patterns, was developed.     

Work–family conflict in work groups: Social information processing, support, and demographic dissimilarity.

We used social information processing theory to examine the effect of work–family conflict (WFC) at the work group level on individuals’ experience of WFC. Consistent with hypotheses, results suggest that WFC at the work group level influences individual WFC over and above the shared work environment and job demands. It was also observed that work group support and demographic dissimilarity moderate this relationship. Moderator analyses suggest that work group social support buffers WFC for individuals but is also associated with a stronger effect of work group WFC on individuals’ WFC. Moreover, the work group effect on individuals’ WFC was shown to be stronger for individuals who were demographically dissimilar to the work group in terms of sex and number of dependents. The interpretations and implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of deformation induced precipitation behaviour in Alloy 718 under two microstructural conditions

Alloy 718 samples under two initial microstructural conditions, viz., solution annealed to form only γ phase (ST) and aged to precipitate only δ particles (DELTA), were deformed in tension till fracture in the temperatures range from 200°C–700°C. From the comparison of the evolved microstructure of deformed and undeformed specimens that have been subjected to similar thermal history, deformation induced precipitation could be identified. Deformation in the range of 550°C to 650°C promoted the precipitation of γ′ and γ″ phases in both structures. In case of DELTA alloy, the γ′ precipitation was found to precede the γ′ phase precipitation while no such preference for precipitation could be identified in ST specimens. This difference in the precipitation behaviour and the sequence of precipitation has been explained on the basis of the relative concentration of solutes in the matrix of the starting microstructures of ST and DELTA specimens.     

Biodiesel production through hydrodynamic cavitation and performance testing

This paper presents the details of development of a biodiesel production test rig based on hydrodynamic cavitation followed by results of experimental investigation carried out on a four cylinder, direct injection water cooled diesel engine operating on diesel and biodiesel blend of Citrullus colocyntis (Thumba) oil. The experiment covers a wide range of engine rpm. Results show that biodiesel of Thumba oil produced through hydrodynamic cavitation technique can be used as an alternative fuel with better performance and lower emissions compared to diesel. The most significant conclusions are that (i) Biodiesel production through hydrodynamic cavitation technique seems to be a simple, efficient, time saving, eco-friendly and industrially viable process. (ii) 30% biodiesel blend of Thumba oil shows relatively higher brake power, brake thermal efficiency, reduced bsfc and smoke opacity with favourable p–θ diagram as compared to diesel.     

Frequency dependent electrical transport properties of 4,4′,4″-tris(N-3-methylphenyl-N-phenylamine)triphenylamine by impedance spectroscopy

The frequency dependent ac conduction mechanism in 4,4′,4″-tris(N-3-methylphenyl-N-phenylamine)triphenylamine (m-MTDATA) has been studied as a function of applied bias and temperature. The Cole–Cole plot shows a slightly depressed semicircle indicating Debye type relaxation. This result has been explained by an equivalent circuit of the device designed as a two parallel resistor and capacitance network in series with contact resistance. The ac conduction studies under dc bias for hole only devices shows an increase in device conductivity with the increase in bias. The variation of bulk resistance with applied bias indicates Space Charge Limited Conduction (SCLC) mechanism for hole conduction. The hole mobility of the material has also been evaluated from SCLC as 8.859 × 10^?6 cm²/V s. The temperature dependent impedance studies show two activation energies indicating two different phase of the material with a phase transition at 235 K.     

Biaxial tensile behavior of spunbonded nonwoven geotextiles

Geotextiles can be successfully employed for any geotechnical application when they are able to sustain pre-defined levels of tensile stresses. The biaxial tensile test has an advantage over other tensile test methods in that it does not allow “necking” during deformation which simulates the operational conditions of geotextiles under confined stresses. In this study, the model for uniaxial tensile behavior of nonwovens has been modified to investigate the biaxial tensile behavior of spunbonded geotextiles. The model has included the effect of fiber re-orientation, stress-strain behavior of constituent fibers, and physical characteristics of nonwovens when the geotextile specimen is laterally constrained. A comparison is made between predicted and experimental stress-strain curves obtained from previous work (Bais-Singh and Goswami, 1998). Theoretical findings of biaxial tensile behavior obtained using the layer theory are also critically discussed. In addition, it has been revealed that fiber re-orientation is a key factor in translating the random spunbonded nonwoven geotextiles to anisotropic structures under defined biaxial tensile stresses.     

Use of chalcopyrite semiconductors CuXSe2 (X=Al,Ga and In) in solar cells: a theoretical study

The energy of sunlight falling on surface of the earth can be directly converted into electricity by means of the solar cells. Among the various materials used for photovoltaics, the chalcopyrite compounds CuXSe₂ (X=Al, Ga, In) are very promising as semiconductors and have received much attention in the recent years. To check the applicability of these materials in solar cells, we have computed the energy bands, density of states, optical dielectric tensors, reflectivity, refraction and absorption coefficients using the full potential linearized augmented plane wave method. It is seen that the energy bandgap reduces from X=Al→In. The dielectric property of these materials is discussed in terms of interband transitions. The absorption coefficients of these materials in the region of solar radiation (0–5 eV energy) are discussed to explore their use in the fabrication of solar cells.