Use of combinatorial analysis for the study of new material for solar cells applications

This paper presents a combinatorial method for the deposition and characterization of new metallic precursors for photovoltaic materials. Onedimensional thin film alloy “libraries” were electrodeposited on Mo-coated glass. The library elements were deposited in two consecutive baths and then heated in a reducing atmosphere to promote interdiffusion of the elements. At the end of this process, the libraries possessed a composition gradient along their lengths, with single elements at their two opposite ends and one or more alloys and/or a solid state solution in between. This continuous range of compositions can therefore be considered a collection of specific precursors that can be interrogated by examining their corresponding locations, with the crystallographic structure along the library changing in accordance with the phase diagram for the metals. The libraries were then sulphurised or selenised by heating in a sulphur-rich or selenium rich atmosphere; this converted the metallic precursors in a continuous range of materials, candidates for potential solar cells absorbers. The libraries were analysed by X-ray diffraction and energy dispersive X-ray spectrometry. The X-ray diffraction results show phase changes across the libraries, which can be correlated with the original precursor concentration at that particular p

Studies of finite element analysis of composite material structures

Research in the area of finite element analysis is summarized. Topics discussed include finite element analysis of a picture frame shear test, BANSAP (a bandwidth reduction program for SAP IV), FEMESH (a finite element mesh generation program based on isoparametric zones), and finite element analysis of a composite bolted joint specimens

Transmission of 0-5- kilovolt electrons by thin films with applications to beta-ray spectroscopy

The penetration of electrons through matter has long been the subject of both theoretical and experimental investigations. Because of simplicity, the investigation frequently deals with a collimated beam of monoenergetic electrons incident normally upon a planar target. Two of the most useful measurements connected with such an experiment concern the range or depth of penetration of electrons in the target, and the intensity of the transmitted beam as a function of incident energy. One object of this research is to determine experimentally range-energy data for thin films. The other object is to measure the transmission of electrons by a thin film and to apply the data to beta-ray spectra obtained using the film as the window in a G-M counter

Magnetized black holes and black rings in the higher dimensional dilaton gravity

In this paper we consider magnetized black holes and black rings in the higher dimensional dilaton gravity. Our study is based on exact solutions generated by applying a Harrison transformation to known asymptotically flat black hole and black ring solutions in higher dimensional spacetimes. The explicit solutions include the magnetized version of the higher dimensional Schwarzschild-Tangherlini black holes, Myers-Perry black holes and five dimensional (dipole) black rings. The basic physical quantities of the magnetized objects are calculated. We also discuss some properties of the solutions and their thermodynamics. The ultrarelativistic limits of the magnetized solutions are briefly discussed and an explicit example is given for the $D$-dimensional magnetized Schwarzschild-Tangherlini black holes.Comment: LaTeX, 23 pages; v2 references and comments added, some typos corrected;v3 minor change

Assessing Predictive Ability of Three Auroral Precipitation Models using DMSP Energy Flux

Our study statistically compares the total energy flux outputs of Newell et al.\u27s (2010a) oval variation, assessment, tracking, intensity, and online nowcasting (OVATION) Prime model, Hardy et al.\u27s (1991) Kp‐based model, and a coupled Space Weather Modeling Framework ring current model to energy flux data obtained from 2198 Defense Meteorological Satellite Program (DMSP) satellite passes in the Northern Hemisphere. Our DMSP data set includes 28 days grouped into continuous 3 and 4 day periods between 2000 and 2008 and encompasses magnetic local times (MLTs) between 04:00 and 21:00. We obtain the most equatorward magnetic latitude coordinate, where a DMSP satellite energy flux measurement exceeds 0.4 erg/cm2/s, and use this point as a proxy for the equatorward boundary of the auroral oval in a particular MLT sector. We then calculate a prediction efficiency (PE) score by comparing the DMSP boundary coordinates to each model, using the same energy flux threshold to obtain a model\u27s boundary location. We find that the PE for the OVATION Prime model is 0.55, and the PE for the Hardy Kp model is 0.51. When we accomplish the same analysis using a higher energy flux threshold equal to 0.6 erg/cm2/s, the OVATION Prime model\u27s PE increases to 0.58, while the Hardy Kp model\u27s score drops to 0.41. Our results indicate that more complex modeling techniques, like those used in OVATION Prime, can more accurately model the auroral oval\u27s equatorward boundary. However, Hardy\u27s discretized Kp model, despite its relative simplicity, is still a competitive and viable modeling option. Abstract © AG

Increases in Cytosolic Calcium Ion Levels in Human Natural Killer Cells in Response to Butyltin Exposure

This study investigated whether exposures to butyltins (BTs), tributylin (TBT), and dibutyltin (DBT) were able to alter cytosolic calcium levels in human natural killer (NK) cells. Additionally, the effects of cytosolic calcium ion increases on the activation state of mitogen-activated protein kinases (MAPKs) in NK cells were also investigated. NK cells are an intital immune defense against the development of tumors or viral infections. TBT and DBT are widespread environmental contaminants, due to their various industrial applications. Both TBT and DBT have been shown to decrease the ability of NK cells to lyse tumor cells (lytic function). TBT has also been shown to activate MAPKs in NK cells. The results of this study indicated that TBT increased cytosolic calcium levels by as much as 100% after a 60-min exposure to 500 nM TBT, whereas DBT increased cytosolic calcium levels to a much smaller extent (and required higher concentrations). The results also indicated that increases in cytosolic calcium could activate MAPKs but only for a short period of time (5 min), whereas previous studies showed that activation of MAPKs by TBT last for at least 6 h. Thus, it appears that TBT-stimulated increases in cytosolic calcium might contribute to, but are not fully responsible for, TBT-induced activation of MAPKs