Structural,viscoelastic, and vulcanization study of sponge ethylene–propylene–diene monomer composites with various carbon black loadings

In this article, we report the effect of various carbon nanoparticle concentrations on the structural, curing, tan δ, viscosity variation during vulcanization, thermal, and mechanical characteristics of ethylene–propylene–diene monomer polymer sponge composites. The purpose of this study was to develop high‐strength, foamy‐structure polymer composites with an optimum filler to matrix ratio for advanced engineering applications. We observed that the structural, vulcanization, viscoelastic, and mechanical properties of the fabricated composites were efficiently influenced with the progressive addition of carbon content in the rubber matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39423.     

Determinants of rural household food security: a comparative analysis of African and Asian studies

This paper reviews the determinants of rural household food security in Africa and Asia where more than 88% of the world's undernourished people live. A conceptual model is proposed on the basis of the three widely known components of food security: food availability, accessibility and utilisation. This model is used to select a total of 40 peer‐reviewed studies carried out over the last decade (20 each from Africa and Asia). A meta‐analysis technique is then used to identify which determinants of food security have been highlighted and how well the causality is demonstrated. Food availability is the most studied component in both regions, followed by food accessibility, while food utilisation is the most neglected component in these studies. © 2013 Society of Chemical Industry     

Evaluation of the differencing pixel-by-pixel change detection method in mapping irrigated areas in dry zones

Geographic information system (GIS) and change detection techniques were used in this study to evaluate the efficiency of an automatic change detection method in detecting and mapping the changes that took place after the implementation of newly irrigated areas in dry zones. Two satellite images were used: Landsat Thematic Mapper (TM) 1983 and Landsat Enhanced Thematic Mapper Plus (ETM+) 2004. The newly implemented irrigated areas were identified using the differencing pixel-by-pixel change detection method. All of these areas were detected over the period 1983–2004. The accuracy of the results obtained from the change detection method applied was determined by spectral and spatial assessment (image interpretation and field surveying). It was shown that all the newly implemented irrigated areas were detected. The assessment of the areas of the new implemented parcels obtained by the current change detection method showed an error of less than 8%. This result is reasonably good if we consider the speed of the process and its low cost for large zones.     

Effect of cobalt-60 γ radiation on the physical and chemical properties of poly(ethylene terephthalate) polymer

The structural, optical, and morphological properties of Co⁶⁰ γ irradiation on poly(ethylene terephthalate) polymer samples were studied with X-ray diffraction (XRD), ultraviolet–visible spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy. The diffraction pattern of virgin sample showed that the polymer was semicrystalline in nature. However, because of irradiation, the crystallinity decreased up to a dose level of 110 kGy and increased up to 300 kGy. The crystallite size, strain, and dislocation were calculated from the XRD data, and the crystallite size decreased from 291.07 to 346.90 Å. The absorption edge shifted from 315 to 330 nm, and the band gap of the samples decreased from 3.79 to 3.66 eV. The SEM micrographs showed radial bulging along with inhomogeneous liner exfoliation, and also, a rocky shape pattern with different sizes was observed. A significant change was found in the Raman spectra of the γ-irradiated polymer at the highest dose. The results of the structural, optical, and morphological studies show recovery characteristics at the highest dose level of 300 kGy. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of γ-irradiation on granule structure and physicochemical properties of starch extracted from two types of potatoes grown in Jammu & Kashmir,India

In this study red and white potato starches were treated with γ-irradiation of 0, 5, 10 and 20 kGy. Physicochemical, pasting and morphological properties of the irradiated starches were investigated. Apparent amylose content, pH, moisture, swelling power and syneresis decreased; whereas carboxyl content, water absorption capacity and solubility increased with increasing irradiation dose. Pasting properties also decreased significantly (p ≤ 0.05) upon increasing the irradiation dose. Observation under scanning electron microscope (SEM) showed surface cracking of the starch granules by γ-irradiation which increased with increase in irradiation dose. X-ray diffraction pattern remained the same upon irradiation but a decrease in relative crystallinity was observed with increasing irradiation dose.     

Software Assisted Digital RF Processor (DRP™) for Single-Chip GSM Radio in 90 nm CMOS

This paper proposes and describes a new software and application programming interface view of an RF transceiver. It demonstrates benefits of using highly programmable digital control logic in an RF wireless system realized in a digital nanoscale CMOS process technology. It also describes a microprocessor architecture design in Digital RF Processor (DRP™) and how it controls calibration and compensation for process, temperature and voltage variations of the analog and RF circuits to meet the required RF performance. A few calibration examples to reduce a DCO bias current and improve device reliability, as well as to optimize transmit modulation and receive performance, are given. The presented circuits and techniques have enabled successful implementation of a commercial single-chip GSM radio in 90 nm CMOS.      

Hybridized synergy effect among TiO2, Pt and graphite silica on photocatalytic hydrogen production from water–methanol solution

The photocatalytic production of hydrogen gas from aqueous methanol solution was performed using powdered mixtures of graphite silica (GS) and platinized TiO₂ (Pt/TiO₂) or those of GS, Pt and TiO₂. The addition of GS to Pt/TiO₂ resulted in the decrease of the amount of H₂ gas, whereas the addition of GS to mixtures of TiO₂ and Pt led to the incremental production of H₂ gas. This effect is attributed to the aggregation of GS, TiO₂ and Pt in suspension. The new additional electron transfer process of TiO₂ → Pt → GS caused the increment of the amount of hydrogen gas.     

An application of univariate marginal distribution algorithm in MIMO communication systems

The paper discusses a sequence detector based on univariate marginal distribution algorithm (UMDA) that jointly estimates the symbols transmitted in a multiple input multiple output (MIMO) communication system. While an optimal maximum likelihood detection using an exhaustive search method is prohibitively complex, it has been shown that sphere decoder (SD) achieves the optimal bit error rate (BER) performance with polynomial time complexity for smaller array sizes. However, the worst‐case complexity of SD is exponential in the problem dimensions, this brings in question its practical implementation for larger number of spatial layers and for higher‐order signal constellation. The proposed detector shows promising results for this overly difficult and complicated operating environment, confirmed through simulation results. A performance comparison of the UMDA detector with SD is presented for higher‐order complex MIMO architectures with limited average transmit power. The proposed detector achieves substantial performance gain for higher‐order systems attaining a near optimal BER performance with reduced computational complexity as compared with SD. Copyright © 2009 John Wiley & Sons, Ltd.