Effect of electron irradiation on the properties of CdTe/CdS solar cells

Polycrystalline CdTe/CdS solar cells are used in space, as well as terrestrial, applications. The results of the studies on the effect of 8 MeV electron irradiation on p-CdTe/n-CdS thin film solar cells prepared by radio frequency (RF) sputtering are presented in this article. Solar cell parameters like short circuit current (I_sc), open circuit voltage (V_oc), fill factor (FF), conversion efficiency (η), saturation current (I_s) and ideality factor (n) have been considered. CdTe thin film solar cells exhibit good stability against electron irradiation up to 100 kGy.     

Energy-efficient bootstrapping for wireless sensor networks

Wireless sensor networks are poised for increasingly wider uses in many military and civil applications. Such applications has stimulated research in a number of research areas related to energy conservation in such networks. Most such research focuses on energy saving in tasks after the network has been organized. Very little attention has been paid to network bootstrapping as a possible phase where energy can be saved. Bootstrapping is the phase in which the entities in a network are made aware of the presence of all or some of the other entities in the network. This paper describes a bootstrapping protocol for a class of sensor networks consisting of a mix of low-energy sensor nodes and a small number of high-energy entities called gateways. We propose a new approach, namely the slotted sensor bootstrapping (SSB) protocol, which focuses on avoiding collisions in the bootstrapping phase and emphasizes turning off node radio circuits whenever possible to save energy. Our mechanism synchronizes the sensor nodes to the gateway’s clock so that time-based communication can be used. The proposed SSB protocol tackles the issue of node coverage in scenarios, when physical device limitations and security precautions prevent some sensor nodes from communicating with the gateways. Additionally, we present an extension of the bootstrapping protocol, which leverages possible gateway mobility.     

Effect of water washing of shark (Scoliodon laticaudus) meat on the properties of proteins with special reference to gelation

The effect of water washing of shark meat on the properties of proteins has been investigated. The contents of low-molecular-weight proteins and urea were reduced significantly with three washing cycles. The gel forming ability showed marked improvement with the number of washing cycles. The dynamic viscoelastic behavior of washed and unwashed meat revealed a structure build-up reaction that was more pronounced in the washed meat. The concentration of myosin heavy chain of washed meat increased as revealed by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Addition of urea at biological concentration (approximately 250 mM) to the washed meat reduced the gel forming ability significantly as compared to unwashed meat. The emulsion capacity showed an increase with the number of washing cycles.     

Effect of ice storage on the functional properties of proteins from shark (Scoliodon laticaudus) meat

Ice storage characteristics of Scoliodon laticaudus with reference to physicochemical and functional properties have been assessed. Total nitrogen content reduced to a value of 3.90 g/100 g from an initial value of 4.27 g/100 g of meat. Moisture content did not show much variation. The initial nonprotein nitrogen content which was 1.09% w/w of meat reduced to 0.98% during ice storage. Urea content of shark meat reduced by 25% during 12 days of ice storage. The increase in total volatile base nitrogen of shark meat was more than twofold at the end of 12 days of ice storage. Solubility of proteins showed an initial increase reaching a value of 87.9%, further reduced with ice storage. Gel filtration profile and SDS-PAGE pattern indicated aggregation of protein fractions and also showed dissociation or cleavage to small molecular weight fractions. Slope of reduced viscosity curve as a function of protein concentration decreased with ice storage period. Emulsion capacity of proteins from shark meat reduced from a value of 0.18 mL oil/mg protein to 0.14 mL oil/mg protein after 12 days of ice storage. Gel forming ability of shark meat monitored by dynamic viscoelastic measurement, gel strength, expressible water content and folding test showed that shark meat has got excellent ability to form gel and this property was marginally reduced during ice storage.     

Antifouling paint booster biocides in UK coastal waters: inputs,occurrence and environmental fate

This study considered the inputs of antifouling paint booster biocides into the aquatic environment directly from painted hulls and high pressure hosing operations, the occurrence of booster biocides in marinas, harbours and docks, and the influence of degradation and water-sediment partition on their environmental fate. Irgarol 1051, the Irgarol 1051 degradation product GS26575, diuron, and the diuron degradation products 1-(3-chlorophenyl)-3,1-dimethylurea (CPDU), 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and 1-(3,4-dichlorophenyl)urea (DCPU) were all detected at measurable concentrations in surface waters. Irgarol 1051, GS26575 and diuron were also detected in bottom sediments. A preliminary study of biocide input during both normal use and foreshore hull hosing showed that hosing may be a significant point source input and also be a cause for future concern since much of this input is in the form of paint particles. Field based measurements and laboratory experiments showed that Irgarol 1051 and diuron persist in the water column, due to a low affinity to partition onto sedimentary material and high resistance to degradation. Other biocides such as chlorothalonil, dichlofluanid, and Sea-Nine 211 were all found to be rapidly removed from the water column and be less persistent.     

Electrical conduction in CuWO4 crystals

The d.c. electrical conductivity and thermoelectric power of CuWO₄ have been measured in the temperature range 300 to 700 K on unannealed and annealed single crystals and on polycrystalline pellets. It has been found that CuWO₄ is an n-type semiconductor. Relevant conduction mechanisms appropriate to the regions below and above 455 K are discussed on the basis of the experimental data on activation energy, mobility and carrier concentration.     

Formation of water-soluble iron oxide nanoparticles derived from iron storage protein

This paper reports novel findings of an investigation of the formation of water-soluble iron oxide nanoparticles from iron-storage protein ferritin. The strategy couples thermal removal of the protein shell on a planar substrate and subsequent sonication in aqueous solution under controlled temperature. Advantages of using ferritin as a precursor include well-defined core size, core composition, water-solubility and processibility. The formation of the nanoparticles was characterized using TEM, UV-Vis and FTIR techniques. Iron oxide nanoparticles in the size range of 5-20 nm diameters were produced. In addition to thermal treatment conditions, the sonication temperature of the nanoparticles in water was found to play an important role in determining the resulting particle size. This simple and effective route has important implications to the design of composite nanoparticles for potential magnetic, catalytic, biomedical sensing and other nanotechnological applications.     

Experimentally determined r13 electro-optic coefficient for a lithium niobate crystal

Experimental determination of the electro-optic coefficient r13 of a lithium niobate crystal is described. The crystal in this experiment is z cut, used as a substrate for a Fabry-Perot etalon. I computed the r13 coefficient from the measured voltage tuning curve of the Fabry-Perot etalon. It is find that the measured value of r13 is lower than most of the reported values in literature.     

Reproducibility and validity of oral visual inspection by trained health workers in the detection of oral precancer and cancer

A randomized intervention trial is in progress in Kerala, India, to evaluate the effectiveness of oral visual inspection by trained health workers (HWs) in the prevention of oral cancer. Fourteen health workers with college graduation as the basic qualification were trained in oral visual inspection to identify oral cancers and precancers among the participants of the screening trial and to refer them for further confirmation and management. The aim of the present study was to evaluate the reproducibility and validity of the screening test provided by the health worker against the reference oral visual findings of three physicians. A total of 2069 subjects who had already been examined were re-examined by the health workers and physicians. The sensitivity and the specificity of the oral visual inspection were 94.3% and 99.3% respectively. There was moderate agreement between the findings of the initial and the repeat mouth examinations carried out by the health workers, which were on average 6 months apart. There was almost perfect agreement (kappa = 0.85) between the findings of the health workers and the physicians in identifying the different types of oral precancerous lesions. The findings of our study indicate that it is possible to train resource persons to perform the oral cancer screening test as accurately as doctors, although experience appears to be a crucial component of health workers' accuracy. The efficacy of such an approach to reduce the incidence of and mortality from oral cancer, however, remains to be proven.