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Contact Materials (contact + material)
Selected AbstractsInfluence from front contact sheet resistance on extracted diode parameters in CIGS solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2 2008Ulf Malm Abstract The extraction of one-diode model parameters from a current,voltage (J,V) curve is problematic, since the model is one-dimensional while real devices are indeed three-dimensional. The parameters obtained by fitting the model curve to experimental data depend on how the current is collected, and more specifically the geometry of the contact. This is due to the non-uniform lateral current flow in the window layers, which leads to different parts of the device experiencing different front contact voltage drop, and hence different operating points on the ideal J,V curve. In this work, finite element simulations of three-dimensional contact structures are performed and compared to experimental data on Cu(In,Ga)Se2 -based solar cell devices. It is concluded that the lateral current flow can influence the extracted parameters from the one-diode model significantly if the resistivity of the front contact material is high, or if there is no current collecting grid structure. These types of situations may appear in damp heat-treated cells and module type cells, respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source] Safety and quality of plastic food contact materials.PACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2003Optimization of extraction time, based on arithmetic rules derived from mathematical description of diffusion., extraction yield Abstract Migration of packaging constituents into food may raise concerns about food safety. This paper describes the conclusions of a EU research project (AIR 941025), aiming to facilitate the introduction of migration control into good manufacturing practice and into enforcement policies. The first part describes a re-evaluation of analytical approaches to extract and identify potential migrants released by plastic materials, viz. comparison of analytical methods, choice of extraction solvents and of fat simulants. Here we focus on the extraction time needed to achieve a given extraction yield. By correlating these parameters with simple and practical equations, it is possible to design alternative tests for control of compliance of packaging plastics. Using a reference experiment (where there is good agreement between experimental and calculated kinetic curves), it is possible to calculate the percentage of extraction which can be achieved in a given time, or the time necessary to reach a target extraction level for other polymer/solvent combinations. A global control scheme is proposed, which indicates whether and when calculation and testing should be applied. Guidelines are proposed, and can be adapted to both industrial control and to enforcement laboratories. Copyright © 2003 John Wiley & Sons, Ltd. [source] QUANTIFICATION AND DISCRIMINATION OF LITHIC USE-WEAR: SURFACE PROFILE MEASUREMENTS AND LENGTH-SCALE FRACTAL ANALYSIS*ARCHAEOMETRY, Issue 3 2009W. J. STEMP This experimental programme employs length-scale analysis of measured profiles to quantitatively discriminate the surface textures of stone flakes manufactured from East Anglian chalk flint used on four contact materials (shell, wood, dry hide and soaked antler). It presents a method for evaluating texture characterization parameters based on their ability to discriminate wear types, and to determine a level of confidence to the discrimination, using the F -test. The results of this experimental work demonstrate that relative lengths, over certain scale ranges, can discriminate the stone tool surface wear profiles produced by the different contact materials. [source] | ||||||||||