Effect of Ni-doping on optical and magnetic properties of solvothermally synthesized ZnS wurtzite nanorods

In this study we have reported the effect of Ni-doping on optical and magnetic properties of ZnS nanorods. The diameter and length of low temperature solvothermally synthesized, high quality nanorods are 10 and 50–300 nm respectively as revealed from transmission electron microscopy. From X-ray diffraction, the structure of Ni-doped nanorods was observed as wurtzite with lattice parameters, a = 3.83 and c = 6.26. The band gap of the undoped and doped samples was found to be blue shifted as compared to the bulk counterpart when analyzed with UV–visible spectroscopy. Quenching in photoluminescence spectra was observed in case of Ni-doped nanorods as compared to undoped counterpart. The magnetization as analyzed from vibrating sample magnetometer was found to increase with 1 and 5 % Ni-doping concentration, and decrease with further increase in Ni-doping concentration, i.e., with 10 % Ni-doping.     

Residential fuelwood consumption in the Southeastern U.S.

A telephone survey of households in 13 states in the southeastern U.S. determined residential fuelwood acquisition and use for heating during the 1991 heating season. Although wood burning accounted for only 10% of the total household heat requirement of the region, it accounted for 51% of the total heat requirements of wood-burning households. One-quarter (25%) of the households burned wood, consuming almost 9 million standard cords. Three-quarters (77%) of wood-burning households reported that wood burning contributed to household heating requirements. Wood as a source of home heating was particularly important to low income households, both rural and urban. Wood is the sole source of home heating for 17% of the wood-burning households in the region.     

RE policy in India: The need for local sensitivity

While at a local level renewable energy success stories abound in India, at the national level, the RE gains seem almost unnoticeable. That is because most of these success stories are due to adoption of renewable energy products - mainly solar systems - by individual households. When it comes to exploiting renewable potential for setting up distributed generation projects that can cater to masses, the country has not scored well. Refocus correspondent, Sunil Puri, India provides his perspective on the current RE situation in India.     

Suggested diagnostic reference levels for paediatric X-ray examinations in India

Exposure of children to ionising radiation is considered to carry higher risk than that of adults; therefore a need to suggest diagnostic reference levels (DRLs) for the common paediatric diagnostic X-ray procedures was recognised for the X-ray machines meeting the requirements of the recently implemented Safety Code for Medical Diagnostic X-ray Equipment and Installations in India. Measurements were carried out for entrance surface air kerma (free in air) in conventional paediatric X-ray diagnostic examinations among four age groups: <1, 1-4, 5-9 and 10-15 y. A total of 2240 air kerma measurements at different fixed focus to skin distances were studied for 7 paediatric diagnostic examinations with 11 different projections on 62 X-ray machines installed in 22 selected hospitals in the country. The third quartile values of air kerma per paediatric examination for the age group of 5-9 y were considered as values of paediatric DRLs. The suggested values of DRLs are 0.2 mGy for chest AP/PA, 0.3 mGy for chest LAT, 0.7 mGy for lumber spine AP, 1.3 mGy for lumber spine LAT, 0.3 mGy for thoracic spine AP, 0.6 mGy for thoracic spine LAT, 0.5 mGy for abdomen AP, 0.7 mGy for pelvis AP, 0.6 mGy for skull PA, 0.5 mGy for skull LAT and 0.8 mGy for hip joints AP.     

Directional distribution of the ambient neutron dose equivalent from 145-MeV ¹⁹F projectiles incident on thick Al target

The directional distribution of the ambient neutron dose equivalent from 145-MeV (19)F projectiles bombarding a thick aluminium target is measured and analysed. The measurements are carried out with a commercially available dose equivalent meter at 0°, 30°, 60° and 90° with respect to the beam direction. The experimental results are compared with calculated doses from EMPIRE nuclear reaction code and different empirical formulations proposed by others. The results are also compared with the measured data obtained from an earlier experiment at a lower projectile energy of 110 MeV for the same target-projectile combination.     

Correlating the phenotypic and molecular diversity in Jatropha curcas L.

Thirty four Jatropha germplasm accessions, selected based on unique phenotypic traits from 180 accessions collected from diverse geographical regions were subjected to field evaluation and molecular analysis. The field evaluation using eight quantitative traits showed significant variation among the germplasm. The molecular analysis using 56 RAPD and 40 ISSR primers resulted in 7 and 8 clusters, respectively. The accession IC541633 from Bastar (Chattisgarh) emerged as the most diverse accession. An attempt has been made to correlate the clustering based on molecular data with the quantitative traits. There was partial correlation between the quantitative traits and molecular data. Interestingly, the diverse accessions according to molecular diversity were characterized by unique phenotypes. Time of flowering, inflorescence type and number, leaf colour and texture were the traits contributing to variation. These traits may be used in identification of diverse accessions during germplasm exploration surveys or short listing of accessions for crossing in Jatropha improvement programmes.     

Structural, morphological, and electrical characteristics of the electrodeposited cobalt oxide electrode for supercapacitor applications

Cobalt oxide (Co₃O₄) thin films were prepared through electrodeposition on copper substrates using an ammonia-complexed cobalt chloride solution. The structural and morphological properties of the film were studied using an X-ray diffractometer and scanning electron microscopy, and the results showed that the electrodeposited cobalt oxide film had a nanocrystalline and porous structure. The electrochemical behavior of the electrodeposited cobalt oxide electrode was evaluated in a KOH solution using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge tests. The electrodeposited cobalt oxide electrode exhibited a specific capacitance of 235 F/g at a scan rate of 20 mV/s. The specific energy and the specific power of the electrode were 4.0 Wh/kg and 1.33 kW/kg, respectively.     

Tuning of magnetic parameters in cobalt-polystyrene nanocomposites by reduction cycling

Cobalt nanoparticles were prepared by a reduction process inside polymer pores using CoSO₄·7H₂O and NaBH₄. A porous polymer network (sulphonated polystyrene) was chosen, as the template for the synthesis of elementary cobalt as high surface area cobalt nanoparticles are prone to oxidation. The preliminary studies reveal that the cobalt is first formed with an oxide protective layer outside and upon repeating the reduction cycles, inner pores of the polymers are opened which enhanced the yield of metallic cobalt. These high surface area cobalt nanoparticles embedded in a polymer are ideal for the synthesis of carbon nanotubes as cobalt can act as a catalyst for the nanotube synthesis. The concentration of cobalt can be tuned in this technique by repeating the cycling process.     

Chrome ore beneficiation challenges & opportunities - A review

Supply of world chromite (chrome ore) has come under severe pressure over the past year driven by strong demand for ferrochrome used in ferroalloy production for making stainless steel. Many of the strategic minerals are inputs into products in fast-changing markets. This article reviews the major process flow sheets in practice for the recovery of chromite values from various types of ores and critical issues related to chromite ore beneficiation. The comprehensive condensation of pertinent facts is intended to provide a single reference source rather than the reader perusing many articles. Emphasis is placed on different processes developed in identifying and solving critical plant problems.     

Using rapid infrared forming to control interfaces in titanium-matrix composites

Control of the fiber-matrix reaction during composite fabrication is commonly achieved by shortening the processing time, coating the reinforcement with relatively inert materials, or adding alloying elements to retard the reaction. To minimize the processing time, a rapid infrared forming (RIF) technique for metal-matrix composite fabrication has been developed. Experiments have shown that the RIF technique is a quick, simple, and low-cost process to fabricate titanium-alloy matrix composites reinforced with either silicon carbide or carbon fibers. Due to short processing times, typically on the order of 1–2 minutes in an inert atmosphere for composites with up to eight-ply reinforcements, the interfacial reaction is limited and well controlled. Composites fabricated by this technique have mechanical properties that are either comparable to or, in several cases, superior to those made with conventional diffusion-bonding techniques.