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Improving Efficiency (improving + efficiency)

Distribution by Scientific Domains
Physics and Astronomy40%
Engineering40%

Selected Abstracts

Improving Efficiency and Value in Health Care: Introduction

HEALTH SERVICES RESEARCH, Issue 5p2 2008
Irene Fraser
First page of article [source]

Improving efficiency in radio surveys for gravitational lenses

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2007
N. Jackson
ABSTRACT Many lens surveys have hitherto used observations of large samples of background sources to select the small minority which are multiply imaged by lensing galaxies along the line of sight. Recently surveys such as SLACS and OLS have improved the efficiency of surveys by pre-selecting double-redshift systems from SDSS. We explore other ways to improve survey efficiency by optimum use of astrometric and morphological information in existing large-scale optical and radio surveys. The method exploits the small position differences between FIRST radio positions of lensed images and the SDSS lens galaxy positions, together with the marginal resolution of some larger gravitational lens systems by the FIRST beam. We present results of a small pilot study with the VLA and MERLIN, and discuss the desirable criteria for future surveys. [source]

Light as a Controlling Tool

LASER TECHNIK JOURNAL, Issue 1 2010
White Light Interferometry in Quality Assurance of Photovoltaic Samples
The photovoltaic industry is characterized by a permanent, substantial growing during the last years. Today improving efficiencies and reduction of manufacturing cost of solar cells is essential for the success in the competitive market. The reduction of manufacturing costs is associated with high volume manufacturing of the solar cells by perpetuation of high quality standards and requirements for small tolerances. Measurements of the topography of solar cells now start to play an important role in the quality assurance of the manufacturing process. It allows the three-dimensional mapping of a complete area with subsequent parameter extraction: so the efficiency of a solar cell depends on the wafer structure: Perfect smooth surfaces absorb less photons than surfaces with a certain, optimized roughness, whereas protecting layers should be as smooth and flat as possible. Similar to all Microsystems the structures can be investigated and compared to the target values: examples are layer thickness, widths and depths of structured lines, the volume-determination of hollows, defects, pores or abrasion/deposition rates. It also encompasses the 3D profile of printed circuit board tracks or special structures for sophisticated high efficiency photovoltaic elements. [source]

SHORT COMMUNICATION: ACCELERATED PUBLICATION: Diode characteristics in state-of-the-art ZnO/CdS/Cu(In1,xGax)Se2 solar cells,

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2005
Miguel A. Contreras
Abstract We report a new state of the art in thin-film polycrystalline Cu(In,Ga)Se2 -based solar cells with the attainment of energy conversion efficiencies of 19·5%. An analysis of the performance of Cu(In,Ga)Se2 solar cells in terms of some absorber properties and other derived diode parameters is presented. The analysis reveals that the highest-performance cells can be associated with absorber bandgap values of ,1·14,eV, resulting in devices with the lowest values of diode saturation current density (,3×10,8,mA/cm2) and diode quality factors in the range 1·30,<,A,<,1·35. The data presented also support arguments of a reduced space charge region recombination as the reason for the improvement in the performance of such devices. In addition, a discussion is presented regarding the dependence of performance on energy bandgap, with an emphasis on wide-bandgap Cu(In,Ga)Se2 materials and views toward improving efficiency to >,1;20% in thin-film polycrystalline Cu(In,Ga)Se2 solar cells. Published in 2005 John Wiley & Sons, Ltd. [source]

DEADLOCK AVOIDANCE FOR FLEXIBLE MANUFACTURING SYSTEMS WITH CHOICES BASED ON DIGRAPH CIRCUIT ANALYSIS

ASIAN JOURNAL OF CONTROL, Issue 2 2007
Wenle Zhang
ABSTRACT Due to existence of concurrent part flows and resource sharing in modern automated flexible manufacturing systems (FMS), deadlock is a common problem and its occurrence causes loss of productivity. When a manufacturing system is modeled by a digraph, existence of circuits in such a graph is a necessary condition for deadlock. Our previous work further showed that the knot and order of a circuit is closely related to impending deadlocks , a type of deadlock that is more difficult to detect. In this paper, we extend our previous work on deadlock avoidance for flexible manufacturing systems to allow choices in process flows (a.k.a., flexible part routing). Due to introduction of choices, part flow dynamics become more sophisticated and our previous results are no longer valid. A systematic circuit analysis is performed in this paper. New concepts such as broken circuit, basic circuit, choice circuit and supremal circuit are introduced to reduce significantly the number of circuits thus improving efficiency of our approach. The extended method is highly permissive with the adjusted effective free space calculation to capture more necessary parts flow dynamics, especially when multiple knots exist in the digraph model. The online policy runs in polynomial time once the set of basic circuits of the digraph is computed offline. Simulation results on selected examples are given. [source]