Generation of electrical energy using lead zirconate titanate (PZT-5A) piezoelectric material: Analytical,numerical and experimental verifications

Energy harvesting is the process of attaining energy from the external sources and transforming it into usable electrical energy. An analytical model of piezoelectric energy harvester has been developed to determine the output voltage across an electrical circuit when it is forced to undergo a base excitation. This model gives an easy approach to design and investigate the behavior of piezoelectric material. Numerical simulations have been carried out to determine the effect of frequency and loading on a Lead zirconate titanate (PZT-5A) piezoelectric material. It has been observed that the output voltage from the harvester increases when loading increases whereas its resonance frequency decreases. The analytical results were found to be in good agreement with the experimental and numerical simulation results.     

The application of dynamic insulation in buildings

Dynamic insulation, a form of ‘Breathing Wall’ construction which allows the movement of air and moisture through the external walls of a building, was seen as one possible method for reducing building envelope heat losses and achieving high indoor air quality. A research investigation was conducted to provide a firm scientific understanding of dynamic insulation. An important outcome of the work will be the development of building envelope designs which effectively and economically employ dynamic insulation in cold climates. This paper presents some general conclusions, confirming that the energy saving produced by dynamic insulation alone is small relative to that obtained in conjunction with conventional air heat recovery methods.     

Socially undesirable sex-correlated characteristics: implications for androgyny and adjustment

Since current measures of sex-role style, such as the Bem Sex-Role Inventory, assess only positive, socially desirable attributes, a set of socially undesirable but sex-typed characteristics was developed and examined in relation to the Bem categories. Data from 100 male and 100 female undergraduates show that androgynous males endorsed the fewest and undifferentiated males endorsed the most numbers of these undesirable characteristics. Feminine-typed females were least likely to use undesirable masculine self-attributes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Failure of triiodothyronine to inhibit TSH-mediated thyroid hormone release in man

We studied the effect of short-term triiodothyronine administration on thyroid gland responsivity to exogenous thyrotropin in four euthyroid human subjects. Thyroidal iodine release and serum thyroxine during daily im injections of bovine TSH were not significantly inhibited, despite a four-fold elevation in serum T3 concentrations. This negative finding contrasts with earlier positive reports of a regulatory "short-loop" effect of elevated circulating T3 on the thyroid gland. This difference may be due either to the use in previous murine or in vitro studies of non-physiologic, high doses of exogenous T3, or failure to control the withdrawal of the trophic effect of endogenous TSH in man on the subsequent glandular response.     

Polyurethane foam (Bentley) micropore blood transfusion filter: filtration characteristics

Stored human blood of varying age was passed through polyurethane foam (Bentley) micropore blood transfusion filters. Passage through these filters resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weights. Numerous microaggregates were removed and SFP returned to normal after filtration. Occlusion of the filter occurred after passage of only 2 units of whole blood. On the basis of this research, we conclude that polyurethane foam (Bentley) micropore blood transfusion filters are effective in removal of microaggregates from stored human blood. Because the filtering capacity is not great, it is recommended that when these filters are used during transfusion a new filter be used for each unit of blood administered.     

Modification and abolition of re-entry within the His-Purkinje system in man by diphenylhydantoin

The phenomenon of macrore-entry (Re) within the His-Purkinje system (HPS) was consistently observed in 10 of 19 patients during retrograde refractory period studies. Effects of intravenous infusion of diphenylhydantoin (DPH) on Re were studied in these 10 patients 10 minutes after completion of infusion (mean plasma level equal to 17.0 microgram/ml). Diphenylhydantoin modified determinants of Re in seven patients (group I) and abolished Re in the remaining three patients (group II). In group I, DPH shortened the critical V1 V2 from 310.0 +/- 30.5 to 292.9 +/- 25.6 msec (P less than 0.025) and critical V2 H2 intervals for Re from 201.4 +/- 18.4 to 185.0 +/- 13.8 msec (P greater than 0.05). In group II, DPH abolished Re in two of three patients by precluding attainment of critical V2 H2 intervals whereas Re was abolished in the remaining one patient despite attainment of critical V2 H2 intervals (vs control). For both groups, DPH significantly shortened functional and effective refractory periods of the HPS (P less than 0.001 and less than 0.01, respectively) without significantly affecting the effective refractory period of the ventricular muscle. Diphenylhydantoin either completely abolished or significantly shortened the retrograde gap zones in the HPS. It is concluded that diphenylhydantoin significantly shortens His-Purkinje system refractoriness, abolishing Re in the patients with higher degree of improvement in refractoriness.     

Serum and urinary zinc levels in urolithiasis

Zinc has an important place amongst inhibitors of crystallisation and crystal growth. These views are supported by in vivo and in vitro studies which suggest that the urinary zinc level is a significant factor in urolithiasis. Some recent studies have given contradictory results. Blood serum and urinary zinc levels were measured in 30 normal healthy controls and 42 stone forming patients (renal, ureteric and vesical). Statistically significant levels were found in all groups, varying according to the number of calculi. Increased urinary zinc levels and decreased serum zinc levels appear to be secondary to the process of stone formation. The role of zinc as an inhibitor of urolithiasis is questionable.