A micromachined carbon nanotube film cantilever-based energy cell

This paper reports a new type of energy cell based on micromachined carbon nanotube film (CNF)-lead zirconate titanate cantilevers that is fabricated on silicon substrates. Measurements found that this type of micro-energy cell generates both AC voltages due to the self-reciprocation of the microcantilevers and DC voltages due to the thermoelectric effect upon exposure to light and thermal radiation, resulting from the unique optical and thermal properties of the CNF. Typically the measured power density of the micro-energy cell can be from 4 to 300?μW?cm(-2) when it is exposed to sunlight under different operational conditions. It is anticipated that hundreds of integrated micro-energy cells can generate power in the range of milliwatts, paving the way for the construction of self-powered micro-?or nanosystems.     

Emerging Regulation and Function of Betatrophin

Betatrophin, also known as TD26/RIFL/lipasin/ANGPTL8/C19orf80, is a novel protein predominantly expressed in human liver. To date, several betatrophin orthologs have been identified in mammals. Increasing evidence has revealed an association between betatrophin expression and serum lipid profiles, particularly in patients with obesity or diabetes. Stimulators of betatrophin, such as insulin, thyroid hormone, irisin and caloric intake, are usually relevant to energy expenditure or thermogenesis. In murine models, serum triglyceride levels as well as pancreatic cell proliferation are potently enhanced by betatrophin. Intriguingly, conflicting phenomena have also been reported that betatrophin suppresses hepatic triglyceride levels, suggesting that betatrophin function is mediated by complex regulatory processes. However, its precise physiological role remains unclear at present. In this review, we have summarized the current findings on betatrophin and their implications.     

Cobalt selenide electrocatalyst supported by nitrogen-doped carbon and its stable activity toward oxygen reduction reaction

We have prepared durable catalysts of CoSe₂/N-carbon using low-cost raw materials, measured their activities, peroxide yields, stabilities in reducing molecular oxygen, and characterized their crystalline phases and morphology. CoSe₂/N-carbon is featured with an active support, N-carbon, which by itself shows high stability as evidenced in its small activity decay. After 1000 CV cycles, the half-wave potential (E_1/2) of N-carbon decreases from 0.667 V to 0.636 V in 0.5 M H₂SO₄. Loading of CoSe₂ enhances the activity of N-carbon, when the samples were synthesized above 385 °C and formulated with the Se/Co ratio higher than 10. The higher activity is attributed to the pyrite phase of CoSe₂. But the stability of pyrite CoSe₂ is less than that of N-carbon. Corrosion during the stability test exposes the active sites of underlying N-carbon, which sustains the catalyst activity. Consequently the E_1/2 value of the active CoSe₂/N-carbon decreases moderately, from 0.711 V to 0.644 V after 1000 CV cycles. In contrast, the E_1/2 value of CoSe₂/C descends much more, from 0.681 V to 0.475 V.     

Liquid Sprays for Heat Transfer Enhancements: A Review

Sprays used for enhanced heat transfer are reviewed, starting from the spray characteristics, measurement methods, and spray dynamics, to spray heat transfer. Some results for spray heat transfer at large Reynolds numbers and surface boiling are also presented, including some recent results summarizing the effects of various injection parameters. It is recommended that basic principles of heat transfer be used to integrate various effects, such as coolant and surface temperatures, water and air flow rates, and injection conditions, into a concise form so that the results can be generalized and be applied to a large range of conditions.     

Study of Brønsted acidity of NaHY zeolite by positron spectroscopy

Angular correlations of positron annihilation gammas were applied to study NaHY zeolite catalysts whose acidity was altered by an ion-exchange process. The Brønsted acidity was found to vary linearly with the lineshape parameter of the angular correlation spectrum of the sample.     

Microwave dielectric properties of (1−x)ZnAl2O4–xCaTiO3 compound ceramic with controlled temperature coefficient

In this study, microwave dielectric properties of (1?x)ZnAl₂O₄?xCaTiO₃ samples with controlled temperature coefficient feature are analyzed. The crystal structures of all the compositions were refined by X-ray diffraction. A homogeneous distribution of cations within instrument sensitivity in all the samples was observed using scanning electron microscopy, coupled with energy dispersive X-ray analysis. ZnAl₂O₄ and CaTiO₃ could coexist when the x content was less than 0.1, whereas Al₂O₃ and Ca₃Al₂O₆ phases were observed in composite ceramics. As expected, the dielectric constant (ε_r) of the composite ceramics increased with the increasing x content, and the quality factor (Qf) generally decreased with increasing x-content because of the low Qf of the CaTiO₃ phases. The temperature coefficient of resonant frequency (τ_f) could be controlled by varying the CaTiO₃ content and could lead to zero τ_f value. The 0.92ZnAl₂O₄?0.08CaTiO₃ ceramic exhibited ε_r of 10.8, Qf of 32,300 GHz, and τ_f of 0 ppm/°C.     

Flow stress and dynamic strain-ageing of β-transformed Zircaloy-4

The 0.2% yield stress of β-transformed Zircaloy-4 was found to be independent of prior-β grain size but varied as the inverse of the transformed β plate width. A dislocation loop expansion model originally proposed by Langford and Cohen [7] for cold-drawn iron wires is used to explain the inverse plate width dependence. Both air-cooled and water-quenched samples exhibited dynamic strain-ageing effects in approximately the same temperature range of 573 to 673 K: (a) a local minimum in strain-rate sensitivity is associated with a peak or an inflection point in the temperature dependence of the 0.2% yield stress for water-quenched or air-cooled samples respectively, and (b) yield drops were observed in strain rate change tests.     

On the adsorption kinetics of an eco-friendly surfactant n-decyl-β-D-maltopyranoside

Eco-friendly surfactant alkyl polyglycosides (APGs) have garnered ample interest in the literature. However, the adsorption kinetics of APGs at an air-water interface has not been studied to date. Consequently, this study aimed at investigating the adsorption kinetics of the APG n-decyl-β-D-maltopyranoside (β-C₁₀G₂) at a freshly created air-water interface. The dynamic and equilibrium surface tension (ST) of the aqueous β-C₁₀G₂ solutions were experimentally measured at varying concentrations using a pendant bubble tensiometer and the ST data were examined via theoretical simulations using the Langmuir and Frumkin models. The fitting results revealed that the Frumkin model (with K = −2.9) well-predicted the equilibrium ST data; signifying a considerable cohesive intermolecular force amidst the adsorbed β-C₁₀G₂ molecules. The theoretical mixed-controlled ST profiles (predicted by the Frumkin model) described the dynamic ST data reasonably well, but the adsorption rate constant increased significantly at increasing concentration. A comparison on the ST data of β-C₁₀G₂ and β-C₁₂G₂ (n-dodecyl-β-D-maltopyranoside) was also conducted and a relatively greater surface-activity and lower cmc of the latter alkyl glycoside was observed.