Chemistry of <Emphasis Type="Italic">Glossodoris</Emphasis> Nudibranchs: Specific Occurrence of 12-Keto Scalaranes

With the aim of establishing whether the oxidation of the tricyclic carbon skeleton of scalaradial (1) is specific to Glossodoris mollusks, the chemical investigation of specimens of Glossodoris pallida from two distinct geographical areas (China and Guam) and of Glossodoris vespa and Glossodoris averni from Eastern Australia was performed. 12-Deacetoxy-12-oxo-scalaradial (4), recently reported from another Glossodoris nudibranch, was the main metabolite of G. pallida from China, G. vespa, and G. averni. A series of scalarane compounds 3 and 5–11, including the unprecedented 12,16-deacetoxy-12-oxo-scalarafuran 5, was isolated from the mollusks. Interestingly, a population of G. pallida from Guam displayed a different scalarane pattern that was characterized by scalaradial (1), deacetyl scalaradial (2), and deoxoscalarin (3), thus confirming previous reports. The specific occurrence of 12-keto-derivatives in some nudibranchs of the genus Glossodoris is discussed.     

Determination of correlations to predict the minimum agitation speed for complete solid suspension in agitated vessels

Experiments were conducted to determine the effects of impeller clearance, impeller diameter, and other operating variables on the minimum agitation speed for off-bottom solid suspension in agitated vessels, N_js, for disc turbines (DTs) and flat-blade turbines (FBTs). Only data for which the impellers produced recirculation flows above and below the impeller (the so-called “double-eight” flow pattern) were considered. Regression equations for N_js were obtained, in which explicit terms for impeller clearance and vessel diameter-to-impeller diameter ratio (T/D) were included. Modified Zwietering equations (Zwietering, 1958) were also obtained, in which Zwietering's parameter S was mathematically expressed as a function of vessel diameter-to-impeller clearance ratio and T/D ratio. When used together with the correlations of Armenante and Uehara Nagamine (1998) for impellers close to the vessel bottom, the equations presented here can be used to calculate N_js for DTs and FBTs for any typical impeller clearance.     

Zinc maleate and zinc anthranilate as thermal stabilizers for PVC

The results of the evaluation of zinc maleate and zinc anthranilate as thermal stabilizers for poly(vinyl chloride) (PVC) are reported in this article. Calcium stearate, diphenyl isodecyl phosphite, and epoxidized soya oil were used as costabilizers. Both zinc compounds showed good stabilizing performance in static and dynamic tests, particularly at low concentrations. The best results were obtained with zinc anthranilate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2603–2605, 2000     

Carbon nanotube thermal interfaces on gadolinium foil

We report the thermal behavior of gadolinium foils to be used in magneto thermoelectric generator cells. Magneto thermoelectric generator cell technology exploits the ferromagnetic phase transition of gadolinium to drive the movement of a diaphragm ‘shuttle’ whose mechanical energy is converted to electrical form and which enhances heat transfer through both conduction and convection. Efficient heat transfer at mechanical interfaces is critical to increase shuttle speed and the commensurate rate of heat transfer. The synthesis and characterization of carbon nanotube thermal interfaces for the gadolinium foils are described. The total thermal interface resistance of the carbon nanotube coated gadolinium was measured using a one-dimensional reference calorimeter technique. Improvement of carbon nanotube growth based on parametric process variations is described, and the effect of hydrogen embrittlement on the magnetic properties of the gadolinium foils during carbon nanotube growth is quantified. The samples generated in this study were consistently measured with total thermal interface resistances in the range of 65–105 mm² K/W, a reduction of 55–70% compared to bare gadolinium (R_int ≈ 230 mm² K/W). The addition of carbon nanotube arrays did not alter the magnetic properties of the gadolinium foils and only a slight decrease in the magnetic moment of the gadolinium samples (8–13%) was measured after growth.     

释放阳光地带的光伏发电潜力

拥有非常丰富的太阳能辐射资源的阳光地带,人口占全球人口总数的75%,电力需求占全球总需求的40%,该地区经济发展受到能源和环境的制约,充分利用丰富的太阳能辐射资源开发光伏发电产业,是可持续发展的重要手段。预测结果表明,范式转型情景中,这些国家的光伏装机容量甚至可达1 100 GW,也就是该地域发电总量的12%;2020年阳光地带国家光伏系统的发电成本将比建设天然气和燃油电站更具竞争力;至2030年光伏发电可以与所有以煤和天然气为燃料的中负荷电厂竞争。阳光地带国家发展股份发电目前还面临着许多障碍,这些障碍涉及到政府对燃油价格的补贴、服务于市场的能力以及能源公司的知识有限等,这些障碍有待于在发展过程中不断克服。中国和印度是阳光地带中的大国,两国的光伏制造业对阳光地带的影响很大。新能源被锁定为中国十二五规划的七大战略性新兴产业之一,中国的十二.五规划的重心是重新平衡经济增长模式,包括逐步扩大内需;国内光伏市场一旦打开,光伏在中国的发展将会非常迅速。释放阳光地带光伏潜力要求众多利益相关者共同参与协作,包括政府、银行和金融机构以及各行各业的支持,才能充分释放阳光地带的光伏发电潜力,带动光伏发电产业链的发展,成为社会经济...     

Short communication: Salt tolerance of Lactococcus lactis R-604 as influenced by mild stresses from ethanol,heat, hydrogen peroxide,and UV light

Lactococcus lactis is a culture widely used in salt-containing dairy products. Salt hinders bacterial growth, but exposure to environmental stress may protect cells against subsequent stress, including salt. The objective of this study was to evaluate the salt tolerance of L. lactis R-604 after exposure to various stresses. The culture was subjected to 10% (vol/vol) ethanol for 30 min, mild heat at 52°C for 30 min, 15 mM hydrogen peroxide for 30 min, or UV light (254 nm) for 5 min and compared with a control. Starting with 5 log cfu/mL for all treatments, growth was determined in M17 broth with 5 NaCl concentrations (0, 1, 3, 5, and 7% wt/vol). Plating was conducted daily for 5 d. Salt tolerance was enhanced with mild heat exposure before growth in M17 broth with 5% (wt/vol) NaCl on d 3, 4, and 5, and with exposure to hydrogen peroxide and ethanol stresses before growth in M17 broth with 5% (wt/vol) NaCl on d 4 and 5. Exposure of this culture to mild heat, hydrogen peroxide, or ethanol before growth in M17 broth containing 5% (wt/vol) salt can enhance its survival, which could be beneficial when using it in salt-containing dairy products.     

Estimation of the thickness and the optical parameters of several stacked thin films using optimization

The reverse engineering problem addressed in the present research consists of estimating the thicknesses and the optical constants of two thin films deposited on a transparent substrate using only transmittance data through the whole stack. No functional dispersion relation assumptions are made on the complex refractive index. Instead, minimal physical constraints are employed, as in previous works of some of the authors where only one film was considered in the retrieval algorithm. To our knowledge this is the first report on the retrieval of the optical constants and the thickness of multiple film structures using only transmittance data that does not make use of dispersion relations. The same methodology may be used if the available data correspond to normal reflectance. The software used in this work is freely available through the PUMA Project web page (http://www.ime.usp.br/~egbirgin/puma/).