Multistress accelerated aging of polymer housed surge arresters under simulated coastal Florida conditions

Long-term performance of polymer housed surge arresters under multistress accelerated conditions simulating coastal Florida service environment in the lab has been presented. Commercial 9 kV ethylene propylene silicone blend (EPSB) and silicone rubber (SiR) arresters were procured and used for this purpose. Multi-stress aging was used to realistically and meaningfully simulate the actual service environment that has the synergy of several environmental stresses. The various stresses applied include ultraviolet-A radiation (UVA), rain, heat, clear mist, and salt fog. Summer and winter weather cycles were designed to apply these stresses cyclically as they occur in the service environment. This method provides a comprehensive evaluation of the insulator, the hardware and its attachment. Coastal Florida conditions were chosen as the year-around warm temperatures and the high humidity challenge any insulating material, ceramic or polymeric. The evaluation was conducted for a period of 15 simulated service years of aging (15 lab-years) in the multistress accelerated aging chamber. Compared to the unaged (virgin) sample, the EPSB arresters showed chalking, reduced hydrophobicity, and reduction in hydrocarbon (CH) group molecules in the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) measurements. The SiR arrester surfaces showed no noticeable changes in the FTIR measurements. However, scanning electron microscopy (SEM) micrographs indicated increased surface roughness and disintegration of the material for both the SiR and EPSB surfaces. Research results indicated that multistress accelerated tests are desirable since they reflect the real world.     

Nonlinear optical absorption and switching properties of gold nanoparticle doped SiO2-TiO2 sol-gel films

The nonlinear optical absorption and switching properties of sol-gel derived of Au nanoparticle doped SiO2-TiO2 sol-gel films having different Au-surface plasmon absorption positions are reported in this paper. The Au nanoparticles are embedded in SiO2 and SiO2-TiO2 mixed glassy film matrices with different refractive index values. To study the nonlinear absorption properties, lasers with three different wavelengths are used. The optical switching behavior is studied by using the pump-probe technique with 532 nm as the excitation wavelength. Ground state conduction band, surface plasmon band, and the free carrier band are taken as three level model to explain theoretically the obtained RSA and SA behaviors.     

Studies of KVIC biogas system coupled with flat plate collector

a simple straightforward transient analysis of the Khadi Village Industrial Commission (KVIC) biogas plant coupled with a flat plate collector through a spiral/coil type heat exchanger is presented. To avoid night heast losses through the collectors, the plant is disassociated from the collectors during off-sunshine hours. The effects of various system parameters, viz. heat capacity of slurry, area of collectros, length of heat exchanger placed in slurry, flow rate, etc. on the variation of slurry temperature have been studied in detail. The results obtained from the proposed system have also been compared with the results of a conventional KVIC biogas plant. It is observed that the drop of slurry temperature in the harsh winter climatic condition can significantly be reduced by the present system, for higher production of biogas.     

Urinary Exosomes Identify Inflammatory Pathways in Vancomycin Associated Acute Kidney Injury

Background: Vancomycin is commonly used as a first line therapy for gram positive organisms such as methicillin resistant Staphylococcus aureus. Vancomycin-induced acute kidney injury (V-AKI) has been reported in up to 43% of patients, especially in those with higher targeted trough concentrations. The precise mechanism of injury in humans remains elusive, with recent evidence directed towards proximal tubule cell apoptosis. In this study, we investigated the protein contents of urinary exosomes in patients with V-AKI to further elucidate biomarkers of mechanisms of injury and potential responses. Methods: Urine samples from patients with V-AKI who were enrolled in the DIRECT study and matched healthy controls from the UAB-UCSD O’Brien Center Biorepository were included in the analysis. Exosomes were extracted using solvent exclusion principle and polyethylene glycol induced precipitation. Protein identity and quantification was determined by label-free liquid chromatography mass spectrometry (LC/MS). The mean peak serum creatinine was 3.7 ± 1.4 mg/dL and time to kidney injury was 4.0 ± 3.0 days. At discharge, 90% of patients demonstrated partial recovery; 33% experienced full recovery by day 28. Proteomic analyses on five V-AKI and 7 control samples revealed 2009 proteins in all samples and 251 proteins significantly associated with V-AKI (Pi-score > 1). The top discriminatory proteins were complement C3, complement C4, galectin-3-binding protein, fibrinogen, alpha-2 macroglobulin, immunoglobulin heavy constant mu and serotransferrin. Conclusion: Urinary exosomes reveal up-regulation of inflammatory proteins after nephrotoxic injury in V-AKI. Further studies are necessary in a large patient sample to confirm these findings for elucidation of pathophysiologic mechanisms and validation of potential injury biomarkers.     

Effect of CTAB coating on structural,magnetic and peroxidase mimic activity of ferric oxide nanoparticles

In the present work, pristine and cetyl trimethyl ammonium bromide (CTAB)-coated ferric oxide nanoparticles \((\hbox {CTAB@Fe}_{2}\hbox {O}_{3} \hbox { NPs})\) were synthesized and studied as enzyme mimics. The w/w ratio of \(\hbox {Fe}_{2}\hbox {O}_{3}\) to CTAB was varied as 1:1 and 1:2. Transmission electron microscopic analysis revealed that pristine NPs had an average size of 50 nm, whereas the presence of CTAB resulted in the formation of nanorods with length of 130 nm. BET studies confirmed enhancement of surface area on CTAB coating, which was maximum for w/w ratio 1:1. The synthesized pristine NPs and CTAB-coated NPs were evaluated for their peroxidase mimic activity using o-dianisidine dihydrochloride as substrate. Optimum pH, temperature, substrate and NPs concentration for the reaction were 1, \(25^{\circ }{\mathrm{C}}\), \(0.16~\hbox {mg}~\hbox {ml}^{-1}\) and \(1~\hbox {mg}~\hbox {ml}^{-1}\), respectively. Peroxidase mimic activity of \(\hbox {CTAB@Fe}_{2}\hbox {O}_{3}\hbox { NPs}\) (w/w 1:1) was higher than that of pristine NPs. However, further increase in CTAB coating (w/w 1:2) resulted in lowering of peroxidase mimic activity. Kinetic analysis was carried out at optimized conditions; maximum velocity (\(V_{\mathrm{max}})\) and Michaelis constant (\(K_{\mathrm{m}})\) value of \(\hbox {CTAB@Fe}_{2}\hbox {O}_{3}\hbox { NPs}\) at 1:1 w/w ratio were 7.69 mM and \(1.12~\upmu \hbox {mol}~\hbox {s}^{-1}\), respectively.     

Ambipolarity Suppressed Dual-Material Double-Source T-Shaped Tunnel Field-Effect Transistor

Silicon - This article proposes a novel dual-material double-source T-shaped tunnel field-effect transistor (TFET) to suppress the ambipolar current conduction. The use of two sources in the...     

Improvement of lecithin as an emulsifier for water-in-oil emulsions by thermalization

The various forms (granular, liquid, gum) of lecithin can be heated under certain conditions of time and temperature to greatly improve their properties as emulsifiers for water-in-oil emulsions. Viscosity, discontinuous phase-holding capacity, stability and water retention were greatly enhanced in emulsions containing thermalized lecithins as the emulsifier compared to those prepared with corresponding amounts of nonthermalized lecithins. The improved emulsification properties of the thermalized lecithins appeared to be due, at least in part, to an increase in diglycerides and free fatty acids resulting from the thermal degradation of phosphatides.     

Influence of peaking capacitors in reducing rise times of high-voltage nanosecond pulses

High-voltage (a few hundred kilovolt), short pulses (microseconds to to nanoseconds) have been found to be effective for various biological decontamination applications, such as cleaning of water with bacteria/algae. Marx generators are most commonly used for this purpose. A serious disadvantage of Marx generators is the increase in rise times due to series inductance. To alleviate this effect, peaking capacitors have been used to produce early time, fast-rising pulses that the Marx generators otherwise cannot supply due to their relatively high series inductance. This paper presents the results of the design and development of a 600-kV, 50-ns-rise-time, and /spl sim/250-ns-duration pulse generator using a peaking capacitor. A 132-kV condenser-type bushing of 650-kV BIL and 230-pF capacitance was used as a peaking capacitor to reduce rise time. The effect of the peaking capacitor was also studied employing circuit modeling of the generator and the influence of various parameters was investigated. There is a good correlation between the experimental and the numerical results.     

Morinda revisited: changes in nutritional well-being and gender differences after 30 years of rapid economic growth in rural Punjab, India

A follow-up study of malnutrition and its determinants among children 6 to 24 months of age was carried out in rural areas of Punjab State in India 30 years after the original study, and following a period of rapid economic growth. The original 1971 study had found a high prevalence of mortality and malnutrition and the worst gender difference in nutritional status ever recorded in an Indian study. The 2001 follow-up study found dramatic reductions in child mortality, child malnutrition, gender-based imbalances in child well-being and care, and family size, the result of participatory economic growth coupled with broad-based educational, health, and family-planning services. Despite overall improvements in caloric intake, however, 40% of lower-class children in 2001 were still consuming less than 50% of their caloric allowance. With minimal gender-based abortion and significantly reduced neglect and mortality offemale children, gender balance among children in this area of rural Punjab improved markedly over the 30-year period.