Characterisation of ZrAl and ZrAlN Thin Films Prepared by Pulsed DC Magnetron Sputtering

Thin films of ZrAl and ZrAlN were deposited on Si(100) substrates in the temperature range 300–773 K and with varying nitrogen flow rate from 0 to 10 sccm by co-sputtering of Zr (99.9 % purity) and Al (99.9 % purity) targets using a single pulsed power supply. At substrate temperature of 773 K, ZrAl thin films crystallized in hcp structure. The nitrogen flow rate was found to significantly influence the phase formation in ZrAlN films with the formation of fcc structure with a nitrogen flow rates in the range 1–2 sccm. The electrical resistivity of ZrAl films decreased from 62 to 24 μΩ cm with increase of substrate temperature, while it increased with nitrogen flow rate as a consequence of change in crystal structure and decrease in the crystallite size. Nanohardness measurements indicated a maximum hardness and elastic modulus of 20 and 369 GPa, respectively for ZrAlN films deposited at 773 K and 1 sccm of nitrogen flow rate.     

Preparation and characterization of molybdenum trioxide from spent hydrodesulfurization catalyst

An approach to produce molybdenum trioxide from spent hydrodesulfurization (HDS) catalyst, obtained from a petroleum refinery, is presented here. The spent catalyst was devolatilized at 600 °C so as to make it free from oils, organics and other volatile species. It was then roasted with sodium carbonate at a temperature of 850 °C for 30 min. The leaching efficiency for 20% soda roasted sample at 10% pulp density was 99.8%. From the solution molybdenum was precipitated out as ammonium molybdate at pH 1.0 with HCl and ammonium chloride. This ammonium molybdate was calcined at 750 °C to get MoO₃. The product was characterized by XRD. Its purity was determined titrimetrically and by ICP-AES.     

Characteristics of a GaN-based Gunn diode for THz signal generation

A generalized large-signal computer simulation program for a Gunn oscillator has been developed.The properties of a Gunn diode oscillator based on the widely explored GaN,are investigated using the dev...     

Evaluation of nerve recovery from minimal-duration crush injury

The recovery of damaged peripheral nerves has been the subject of multiple studies. The effects of an inadvertent clamping of a nerve has not been well examined. An experiment was performed to evaluate the effects of a minimal-duration crush injury on the rat sciatic nerve and to determine if walking track analysis was useful in evaluating the short-term functional deficit. Ten Sprague-Dawley rats underwent high-pressure, short-duration crush injuries. Walking track analysis was done regularly for 3 weeks. Histological specimens for light and electron microscopy were taken at postoperative days 3, 7, 14, 21, and 42 from similar animals. There was significant decrease in function by the second week, which then improved to control levels after week 3. Toluidine blue and electron microscopic findings confirmed the clinical course, while routine histological findings tended to lag behind the return of function. Walking track analysis appears to be an effective method of evaluating the short-duration nerve crush injury.     

An adaptive linear combiner for on-line tracking of power systemharmonics

The paper presents a new approach for the estimation of harmonic components of a power system using a linear adaptive neuron called Adaline. The learning parameters in the proposed neural estimation algorithm are adjusted to force the error between the actual and desired outputs to satisfy a stable difference error equation. The estimator tracks the Fourier coefficients of the signal data corrupted with noise and decaying DC components very accurately. Adaptive tracking of harmonic components of a power system can easily be done using this algorithm. Several numerical tests have been conducted for the adaptive estimation of harmonic components of power system signals mixed with noise and decaying DC components     

Frost heave in helium & other substances

A thermomolecular pressure associated with a thermal gradient produces the phenomenon known as frost heave in moisturecontaining frozen ground. Thermomolecular pressures can occur in any material. The basic requirement is a perturbed region of phase equilibrium extending to temperatures below the bulk phase boundary, such as the liquid film at an interface undergoing surface melting. Two materials that have exhibited thermomolecular pressure effects to date are ice in various porous media andHe ⁴ in Vycor glass. Thermomolecular pressures and their dynamical effects offer a unique way of studying quantum and classical liquids at interfaces.     

Effect of high pressure on mass transfer kinetics of granny smith apple

The mass transfer kinetics during osmotic dehydration of granny smith apple slices in 60 Brix fructose and sucrose solution was studied at atmospheric pressure and at elevated pressure of 200–600?MPa at 40°C. The moisture and solute fractions in apple slices during osmotic dehydration under high pressure were predicted by Weibull frequency distribution model. The calculated effective moisture diffusivity values of apple slices suspended in fructose and sucrose solution during high-pressure treatment (0.1–600?MPa) were in the range of 6.35?×?10^?10 to 3.60?×?10^?9?m²/s and 7.96?×?10^?10 to 4.32?×?10^?9?m²/s, respectively.