Effect of sintering temperature on electrical characteristics of ZnO-0.5 mol% V2O5-2 mol% MnO varistors

The effect of sintering temperature on the microstructure and the electrical response of liquid phase sintered ZnO-V2O5 varistor ceramics were analyzed using A.C impedance spectroscopy on samples prepared via conventional solid route. The impedance spectra were analyzed with the help of the model equivalent circuit at high frequencies and another at low frequencies, involving both resistor and constant phase element (CPE). The results indicate a significant contribution of grain boundary resistance to the non-ohmic characteristic of the studied materials.

The products were characterized regarding phase with X-ray diffraction, microstructures with SEM. Electrical characteristics were studied with impedance analysis and current-voltage characterization. In the present investigations studies, have been made on the effect of sintering temperatures (850°C, 900°C, and 950°C) on the microstructure and electrical properties of MnO and MgO doped ZnO-0.5 mol% V2O5 varistor system. The phase composition of samples consists mainly ZnO grains, while Zn2VO4 is the secondary phases. Better varistor performance has been achieved for the samples sintered at 950°C with nonlinear coefficient α=16, breakdown voltage 2513.3 V/mm and leakage current is JL=7.7 × 10-5 A/cm2. SEM analysis of morphology shows that the grain growth increases with increase in sintering temperature.

Usefulness of a nutraceutical diet to improve qol and drugs use in a dog affected by a mast cell tumor: a case report

On October 2014, a 10-years-old male neutered boxer presented to the Wiligelmo Veterinary Clinic of Modena (Italy) for the sudden onset of 3 cutaneous nodular lesions. The first, a large movable lesion, was clearly visible on the dorsal face of the second finger of the right forepaw, which was linked to the paw by means of a tight peduncle. Intriguingly the skin of this lesion resulted intact, neither alopecic nor with signs of dermatitis. The second lesion, on right side of the tail, was subcutaneous, poorly movable and with a blackish, alopecic but not ulcerated skin. The same features characterized the third lesion on the left dorsal side of the gluteus region.

Continuous system of freeze concentration of sucrose solutions: Process parameters and energy consumption

Continuous processes to freeze-concentrate aqueous solutions of sucrose are proposed that integrates the falling film technique, fractionated thawing, and block freeze-concentration. Data reported in our previous studies were used to study the two first techniques. Block freeze concentration tests were performed to recover the solutes present in the diluted fractions.

Starting with a solution with 5% w/w solids, a concentrated liquid with 20% w/w solids and an effluent with 0.3% w/w solutes were obtained. The falling film freeze technique effectively concentrated the sucrose solution. Fractionated thawing increased the recovery of solutes retained in the ice from 39 to 50%. Block freeze concentration increased solute recovery to 95%. A concentration index of 4.0 and a concentration efficiency of 98.5% were obtained by integrating the techniques. Under the assumptions considered in this work, theoretically the energy consumption of the process can reach a value of 10.3 kWh/1000 kg of ice removed, which represents a saving of 30% compared to the energy consumption of the most efficient evaporation systems.

Practicality and importance of selected endothelial dysfunction measurement techniques ‐ Review

The measurement of endothelial dysfunction (ED) has importance in that it indicates the presence of coronary artery disease in addition to acting as a predictor of future adverse events. Various tools, methods, and metrics exist that can provide an indicator of endothelial dysfunction. Given the significance of ED, it is of utmost importance to find a measurement technique that is reliable, while defining a metric providing a framework for an overall system that is practical, accurate, and repeatable. Success would provide a tool for early detection of cardiovascular disease not only moving patients that are currently classified as asymptomatic to symptomatic but also providing a method to monitor efficacy of treatments.