Preparation and characterization of conductive polypyrrole/kaolinite composites

Conductive polypyrrole (PPy)/kaolinite clay composites were prepared by in situ chemical polymerization of pyrrole in the presence of kaolinite using FeCl₃ as oxidant. The PPy content and conductivity of the composites reached 32.8% and 8.3×10^?2 S/cm at HCl concentrations of 1.5 M and 0.5 M, respectively. The microhardness of the composites containing different amounts of PPy was higher than that of the PPy and kaolinite components. The highest microhardness observed was 30.17 kg/mm² for the composite containing 9.6% PPy. The electrical resistance of the composites was monitored during heating–cooling cycles over the range 5–120 °C. The change in resistance with temperature was more repeatable for the composite than for PPy. The composites were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The humidity-sensing properties were also examined.     

Fabrication of Pb1‐xSnxTe/PbTe heterojunctions by liquid phase epitaxy

Abstract

Pb_1‐x Sn _x Te epitaxial layers were successfully grown on PbTe substrates by liquid phase epitaxy (LPE) technique. The compositions and surface morphology of the epitaxial Pb_1‐x Sn _x Te layers were controlled in the LPE growth, and p‐Pb_1‐x Sn _x Te/n‐PbTe heterodiodes with a good junction‐perfection factor were made.     

Evaluation of in-air hand gestures interaction for older people

Universal Access in the Information Society - In-air gestural interfaces are gaining popularity due to the increasing availability and low cost of gesture recognition hardware. However, the current...     

Particle-based simulation of the interaction between fluid and knitwear

We present a particle-based method to simulate and visualize the interaction of knitwear with fluids. The knitwear is modeled using spring-mass systems and the fluid is modeled using the smoothed particle hydrodynamics method. Two-way coupling is achieved by considering surface tension, capillary, and interparticle forces between the fluid and knitwear. The simulation of fluid and knitwear particles is performed on the graphics processing unit. Photorealistic rendering of knitwear and fluid is achieved by using a hardware-accelerated rasterization-based rendering technique. Our method is able to simulate and visualize the macro- and microstructure of free-form knitwear and reflective and refractive characteristics of the fluid surface.     

A likelihood-based framework for the analysis of discussion threads

Online discussion threads are conversational cascades in the form of posted messages that can be generally found in social systems that comprise many-to-many interaction such as blogs, news aggregators or bulletin board systems. We propose a framework based on generative models of growing trees to analyse the structure and evolution of discussion threads. We consider the growth of a discussion to be determined by an interplay between popularity, novelty and a trend (or bias) to reply to the thread originator. The relevance of these features is estimated using a full likelihood approach and allows to characterise the habits and communication patterns of a given platform and/or community. We apply the proposed framework on four popular websites: Slashdot, Barrapunto (a Spanish version of Slashdot), Meneame (a Spanish Digg-clone) and the article discussion pages of the English Wikipedia. Our results provide significant insight into understanding how discussion cascades grow and have potential applications in broader contexts such as community management or design of communication platforms.     

EasyCar: Location-Aware Assistance System Based on Smartphone in Automotive Aftermarket

Cloud databases provide facilities for large scale data storage and retrieval of distributed data. However, the current access control techniques provided in database systems for maintaining security are not sufficient to secure the private data stored in public cloud databases. In this paper, a new secured data storage algorithm for effective maintenance of confidential data is proposed. To perform storage and retrieval operations of data in the cloud data storage effectively, map reduce algorithms are developed in this work which performs data reduction and fast processing. In order to consider the temporal nature of documents to be retrieved, we propose a new algorithm called Temporal Secured Cloud Map Reduced Algorithm which integrates temporal constraints with map reduce algorithms and also the chaining Hill Cipher encryption algorithms which is proposed newly in this work. The main advantages of the proposed algorithm is that they reduce the processing time and maintains security effectively. The experimental results obtained from this work depict that the proposed model is optimizing cost and it ensures data security.

     

Effects of pretreatment and various operating parameters on permeate flux and quality during ultrafiltration of apple juice

The central composite design with a quadratic model was used to investigate the effect of temperature (20–40 °C) and transmembrane pressure (TMP) (100–300 kPa) as well as pretreatment with gelatin and bentonite (0:0–300:1500 mg L^?1) on permeate flux and fouling resistance during ultrafiltration of apple juice. The changes in some physicochemical properties were also investigated. Pretreatment of apple juice with gelatin and bentonite and an increase in the temperature and TMP significantly improved the permeate flux. In general, physicochemical properties of apple juice other than polyphenolics were not affected by the applied parameters. Using 150 mg L^?1 of gelatin and 750 mg L^?1 of bentonite for fining significantly reduced the total phenolic content and so did the fouling resistance. Fouling resistance also decreased with increasing temperature, and increasing pressure increased the fouling resistance.     

Study of the dimensional instabilities of laminated polypropylene films during heating treatments

Ensuring the geometrical stability of organic coatings is a key challenge for steel/polymer composites produced by the automotive industry to reduce the cars' weight. During the thermal treatment of painting, which exceeds the melting temperature of the organic part of the laminated film, polymer shrinkage may occur. It induces uncovered parts of the steel sheet which would present negative corrosion behavior in use. Two original and innovative experiments were presented. They enable to measure the deformation induced by the shrinkage and then to identify the microstructural mechanisms responsible for its appearance. Main results show strong influences of the macromolecular chains orientation induced by the film extrusion process and of the postheating parameters used to perform the painting curing. Raman spectroscopy and differential scanning calorimetry are used both to perform analysis of the microstructure evolution during heating treatments in terms of crystals melting, crystalline macromolecular chains disorientation, and volume damage healing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012