Enhancement of room temperature ferromagnetism in Cd1−xNixSe nanoparticles

Cd_1?xNi_xSe (x = 0.0, 0.02, 0.05 and 0.1) nanoparticles have been synthesized by chemical route. X-ray diffraction analysis shows crystalline nature of synthesized nanoparticles possessing wurtzite phase having hexagonal structure. Transmission electron microscopy depicts spherical morphology and uniform particle size distribution of pure and Ni-doped CdSe nanoparticles. The blue-shift in band gap has been observed with Ni-doping concentration. Photoluminescence study shows the presence of intrinsic defects (V_Cd–V_Se) in the synthesized nanoparticles. Electron spin resonance (ESR) analysis reveals the long range ferromagnetic ordering in pure and doped nanoparticles. ESR study also indicates that Ni ions exist in +2 oxidation state in host nanoparticles. The magnetic hysteresis (M-H) loops display ferromagnetism at room temperature in pure and Ni-doped CdSe nanoparticles. The increase of ferromagnetic behavior has been observed with Ni-doping concentration. M-H analyses indicate that defects and carrier mediated exchange interactions are responsible for ferromagnetic ordering, in the present study.     

Separation of nickel from copper in ammoniacal/ammonium carbonate solution using ACORGA M5640 by selective stripping

Separation of nickel from copper in ammoniacal/ammonium carbonate solution using ACORGA M5640 by selective stripping was carried out. The influence of equilibration time, equilibrium pH and extractant concentration on the extraction of both the metals was studied. It was found that the copper extraction equilibrium was reached in a shorter time than the nickel extraction equilibrium. Nickel extraction decreases above an equilibrium pH of 9.0, while the extraction of copper remains unaffected by the changes in the equilibrium pH range of 7–10. Co-extraction, ammonia scrubbing and the selective stripping of copper and nickel were performed for a solution containing 3 g/l each of copper and nickel and 60 g/l ammonium carbonate. The extraction and the percentage stripping of copper and nickel were almost quantitative.     

Combined Effect of Turbulence,Load Orientation and Rotor Flexibility on the Performance of Three-Lobe Bearings

A three-lobe journal bearing is analytically investigated to determine its dynamic performance when three main parameters, i.e. turbulence, load orientation, and rotor flexibility are varied. Reynolds numbers up to 12000, rotor dimensionless flexibilities up to 4, and load orientations up to 30 degrees on either side of the vertical load line are considered. Thus, almost all cases of practical interest are studied. The stability of a three-lobe bearing improves due to turbulence at high Sommerfeld numbers (more than 0.6) for a rigid rotor, while it is virtually the same for flexible rotors. Conversely, the load orientation has a pronounced effect on stability for both rigid and flexible rotors.     

Neodymium triflate modified nafion composite membrane for reduced alcohol permeability in direct alcohol fuel cell

This paper reports an experimental study on the modification of nafion membrane with neodymium triflate, Nd(SO₃CF₃)₃, a rare earth triflate. The triflate ion resembles nafion in structure and has high lewis acidity, high coordination number, hygroscopic nature and thermal stability. These properties make the neodymium triflate (NdTfO) suitable to improve the performance of NdTfO/nafion membranes in direct alcohol fuel cell by reducing fuel permeability without compromising other properties. The NdTfO/nafion membranes reduced alcohol permeability by nearly 48%. The proton conductivity of 1% NdTfO/nafion was increased by at least 24% as compared to pure cast nafion membrane. The mechanical strength of 1% NdTfO/nafion was higher than that of pure cast nafion. The composite membrane was thermally and chemically stable and has potential for use in direct alcohol fuel cells. A DMFC was developed and its performance was evaluated using the composite membrane, which showed encouraging results.     

A High-Density 45 nm SRAM Using Small-Signal Non-Strobed Regenerative Sensing

High-density SRAMs utilize aggressively small bit-cells, which are subject to extreme variability, degrading their read SNM and read-current. Additionally, array performance is also limited by sense-amplifier offset and strobe-timing uncertainty. This paper, presents a sense-amplifier that targets all of these performance degradations: specifically, simple offset compensation reduces sensitivity to variation while imposing minimal loading on high-speed nodes; stable internal voltage references serve as an internal means to self-trigger regeneration to avoid tracking mismatch in an external strobe-path; precise small-signal detection withstands small read-currents so that other bit-cell parameters can be optimized; and single-ended sensing provides compatibility to asymmetric bit-cells, which can have improved operating margins. The design is integrated with a 64-kb high-density array composed of 0.25 mum² 6T bit-cells. A prototype, in low-power 45 nm CMOS, compares its performance with a conventional sense-amplifier, demonstrating an improvement of 4X in access-time sigma and 34% in overall worst case access time.     

Batch and continuous studies on treatment of pulp mill wastewater by Aeromonas formicans

Batch and continuous studies have been conducted on the treatment of black liquor from a kraft pulp and paper mill by a bacterial strain, Aeromonas formicans. The results of batch studies revealed that the strain was able to remove 71% and 78% of COD and lignin respectively, while the colour removal efficiency was around 86% in 10 days of retention time. The analysis of lignin degradation products by gas chromatography after 20 days of incubation revealed the formation of some phenolic acids, which were responsible for the decrease in pH during batch studies. The removal efficiencies of COD, colour and lignin obtained in continuous reactor studies were 73, 88 and 77% respectively for an 8 day detention period and these efficiencies were almost the same as obtained in batch studies. © 2001 Society of Chemical Industry     

Correction to: Comparative analysis of limit equilibrium and numerical methods for prediction of a landslide

Bulletin of Engineering Geology and the Environment - Landslides that occur due to the rapid motion of a rock-mass are a primary risk in mountainous terrains and are a danger to human life and...