Impact of oxygen concentration during the deposition of window layers on lowering the metastability effects in Cu(In,Ga)Se2/CBD Zn(S,O) based solar cell

The purpose of the present paper is to focus on the impact of oxygen gas partial pressure during the sputtering of i‐ZnO and ZnMgO on the transient behavior of Cu(In,Ga)Se₂ (CIGSe) based solar cells parameters when a CBD‐Zn(S,O) buffer layer is used. Based on electrical characterization of cells, it is observed that the effect of light soaking is different on J–V characteristics depending on whether oxygen is or is not present during the first deposition time of the i‐ZnO or ZnMgO layers. In fact, when cells are prepared with standard i‐ZnO, the efficiencies are very low and a pronounced transient behavior is observed. However, when the first 10 nm of i‐ZnO or ZnMgO is formed by sputtered layer without adding oxygen during the process, depending on the thickness of the buffer layer, the transient effects strongly decreases. It is then possible to get stable cells reaching efficiencies quite similar to the CdS reference cells, especially with ZnMgO, without any post‐treatments. Copyright © 2015 John Wiley & Sons, Ltd.     

Physical aging in polymers: Comparison of two ways of determining narayanaswamy's parameter

In this work, we have investigated by differential scanning calorimetry the enthalpy relaxation of two poly[methyl(α-n-alkyl)acrylates] in which it is possible to change the length of the two alkyl chains. In particular, we have evaluated the Narayanaswamy parameter, which controls relative contribution of temperature and of structure to the relaxation times, by two methods: Grenet's method (GM) and the peak-shift method (PSM). The data obtained show that both methods lead to equivalent results. Nevertheless, PSM requires fewer experiments than GM, and PSM appears to be more practical. The results obtained on the two acrylates show that the parameter x increases with the lateral chain length, that is to say, that the temperature effects increase as the length of the alkyl chain is increased.     

Radical‐scavenging properties of extracts from the white button mushroom,Agaricus bisporus

BACKGROUND: Agaricus bisporus is the premier cultivated edible mushroom but is usually considered to be of lesser value nutritionally and medicinally compared with other cultivated mushrooms. The objective of this study was to investigate the radical‐scavenging properties of methanolic extracts and the free radical‐processing enzyme activities of water extracts from A. bisporus fruit bodies. Analyses were performed on total fruit bodies from three strains and on separated stipe, cap and gills from one strain, all cultivated experimentally under the same conditions. RESULTS: EC₅₀ values of scavenging ability on 1,1‐diphenyl‐2‐picrylhydrazyl radicals (DPPH^?), scavenging ability on 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cations (ABTS^?+) and reducing power of methanolic extracts from total fruit bodies ranged between 1.7 and 5.0 and were 1.1–1.9 times higher in a white hybrid than in two wild strains, cream and brown. The gills exhibited higher antioxidant activities relative to the stipe and cap. In water extracts, glutathione peroxidase activities were up to eight times higher than glutathione reductase activities and no difference was observed between strains. Catalase activity was highest in the brown wild strain. The only significant differences in free radical‐processing enzymes between the three parts of the mushroom were higher catalase activity in the gills and lower glutathione reductase activity in the stipe. CONCLUSION: The radical‐scavenging properties of the button mushroom are comparable to those of other edible mushrooms and dependent on the strain and on the section of the fruit body. Copyright © 2008 Society of Chemical Industry     

The catalysis of the Ruff oxidative degradation of aldonic acids by titanium‐containing zeolites

Ti‐BEA and Ti‐FAU, obtained by post‐synthesis treatment, and TS‐1, obtained by direct hydrothermal synthesis, have been tested as catalysts for the Ruff oxidative degradation of calcium d‐gluconate to d‐arabinose using diluted hydrogen peroxide as oxidant. Only large‐pore zeolites Ti‐BEA and Ti‐FAU were found to be active. It was shown, in particular, that a very rapid leaching of titanium occurred and that the titanium species present in the solution were responsible for the catalytic activity observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Incorporation and metabolic conversion of erucic acid in various tissues of the rat in short term experiments

Rats were intravenously injected with a mixture of free (14-¹⁴C) erucic acid (22∶1) and (9–10³H) oleic acid (18∶1). After 2, 4, 8, 16, and 30 min, radioactivity was examined in blood, liver, heart, kidneys, and spleen. Free (¹⁴C) 22∶1 disappeared from the blood more rapidly than free (¹⁴C) 18∶1 between 0 and 8 min. Incorporation of label into triglycerides only appeared after 16 min and at 30 min they represented 4% of the injected radioactivity. In this fraction, 63% of¹⁴C radioactivity was present as 18∶1 and not as the original 22∶1, while almost all³H radioactivity was recovered as unchanged 18∶1. At all times studied, the majority of radioactivity was found in the liver, primarily as triglycerides (60% of radioactivity in total lipids) and as phospholipids (20–30%).¹⁴C was present in nearly the same proportion as³H (13% of injected radioactivity after only 2 min, 11% at 30 min).¹⁴C radioactivity was contained in 18∶1 in higher proportion than 22∶1 (45% in triglycerides, 65% in phospholipids). Since labeled triglycerides of blood, rich in (¹⁴C) 18∶1, mainly originate from the liver triglycerides, it appears that 18∶1 is the major form of utilization of 22∶1 in the tissues after its conversion in liver. In the other organs tested, radioactivity was found 10–15 times lower than in liver. In the heart,¹⁴C was 3 to 4 times higher than³H. More than 80% was recovered as 22∶1 in triglycerides. In spleen and kidneys, the¹⁴C:³H ratio was particularly high in free fatty acids and monoglycerides. In kidneys, 60% of¹⁴C was present as nervonic acid (24∶1) in monoglycerides and 40% in phospholipids, suggesting that the mononervonin formed was used for phospholipid biosynthesis. A preliminary report of this work was presented at the 10th International Congress of Nutrition, Kyoto, Japan, August 1975.     

Melt‐stable poly(1,4‐dioxan‐2‐one) (co)polymers by ring‐opening polymerization via continuous reactive extrusion

Bulk polymerization of ?‐caprolactone (CL), 1,4‐dioxan‐2‐one (PDX), and mixtures of PDX and CL was carried out by initiation with Al(O^secBu)₃ in a co‐rotating twin‐screw extruder through a fast single‐step process. Both homopolymerizations and copolymerization of PDX and CL proceed very rapidly and reach almost complete (co)‐ monomer(s) conversion as soon as 8 mol% of CL are added in the feed. Even though poly(1,4‐dioxan‐2‐one) (PPDX) is known to thermally degrade mainly through unzipping depolymerization promoted from the hydroxyl end‐groups and yielding PDX monomer, it turns out that the thermal stability of PPDX chains is substantially improved by the copolymerization of PDX with limited amounts of CL. Interestingly, DSC analysis of the so‐obtained P(PDX‐co‐CL) copolymers has demonstrated that a CL molar fraction as high as 11 mol% does not prevent the crystallization of the resulting copolymer, which retains a melting temperature close to 95°C. This last observation has been explained by the formation of a blocky‐like copolymer structure, in which short PPDX and PCL sequences are randomly distributed. POLYM. ENG. SCI., 45:622–629, 2005. © 2005 Society of Plastics Engineers.     

Three-dimensional h-adaptivity for the multigroup neutron diffusion equations

Adaptive mesh refinement (AMR) has been shown to allow solving partial differential equations to significantly higher accuracy at reduced numerical cost. This paper presents a state-of-the-art AMR algorithm applied to the multigroup neutron diffusion equation for reactor applications. In order to follow the physics closely, energy group-dependent meshes are employed. We present a novel algorithm for assembling the terms coupling shape functions from different meshes and show how it can be made efficient by deriving all meshes from a common coarse mesh by hierarchic refinement. Our methods are formulated using conforming finite elements of any order, for any number of energy groups. The spatial error distribution is assessed with a generalization of an error estimator originally derived for the Poisson equation.Our implementation of this algorithm is based on the widely used Open Source adaptive finite element library deal.II and is made available as part of this library's extensively documented tutorial. We illustrate our methods with results for 2-D and 3-D reactor simulations using 2 and 7 energy groups, and using conforming finite elements of polynomial degree up to 6.     

Secure Self-healing Group Key Distribution Scheme with Constant Storage for SCADA Systems in Smart Grid

Wireless Personal Communications - Smart grid has a great advantage over the traditional power grid and it is a critical condition in people’s daily life. The security of data communication...     

The role of user requirements in data repository design

International Journal on Software Tools for Technology Transfer - Requirements engineering plays a crucial role in the development process of an information system as it aims at providing a...