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Efficient Design (efficient + design)
Selected AbstractsThe Economics of HIV/AIDS: A SurveyDEVELOPMENT POLICY REVIEW, Issue 1 2003Edoardo Gaffeo This article surveys the main economic issues associated with the HIV/AIDS epidemic, paying special attention to sub,Saharan Africa. It explores the economic and behavioural determinants of HIV transmission, the microeconomics of market failures associated with high HIV prevalence, the prospects for regional development from a macroeconomic perspective and the efficient design of policies for coping with the epidemic. In line with the recent appeal by the UN Secretary General, the article argues that, without a decisive effort to halt HIV/AIDS, people living in the region are bound to experience a further fall in their standard of living in both relative and absolute terms. However, to be effective, anti,AIDS programmes must be rooted in sound economic principles. [source] Analysis of optical and terahertz multilayer systems using microwave and feedback thoeryMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2009Dong-Joon Lee Abstract The principles of microwave and feedback theory are independently applied to the analysis of both optical and terahertz-regime multilayer systems. An analogy between the two approaches is drawn, and useful recursion relations, along with a signal-flow approach, are presented for both reflection and transmission cases. These relations, in terms of S-parameters, allow an exact analytical solution for even arbitrary, active, stratified structures, not only for any wavelength in the radio-frequency spectrum, but also for optical wavelengths. This approach also provides a bridge between the microwave and optical bands and leads to beneficial design solutions for intermediate bands such as the THz regime. Comparisons with conventional methodologies are provided using practical multilayer simulations. In addition, graphical design techniques from microwave theory are used along with examples for efficient design and understanding. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1308,1312, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24301 [source] An Integrated Atmospheric Microwave Plasma SourcePLASMA PROCESSES AND POLYMERS, Issue S1 2009Reinhold Kovacs Abstract Atmospheric plasma processes become more and more popular in recent times. A new integrated atmospheric plasma source is presented which consists of a microwave resonator combined with a solid-state power oscillator. This allows for a very compact and efficient design of a microwave plasma source without external microwave power supply and matching units. Hydrophobic polymers have to be activated to ensure an effective painting or glueing. The performance of this new plasma source has been investigated with respect to surface activation depending on axial and radial distance to the substrate, process time, process gas, and flow velocity. Several polymeric materials have been compared. Polyethylene, polyamide, polystyrene, polypropylene, polycarbonate, and polytetrafluorineethylene show good activation results. This tool can be used especially for bulky goods and/or mass products, when a vacuum process is not possible or too expensive. [source] A partition experimental design for a sequential process with a large number of variablesQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2007Leonard A. Perry Abstract Statistically designed experiments provide a systematic approach to study and analyze the effects of multiple factors on process performance. In order to improve the performance across an organization, one must investigate multiple processes from supplier to customer. Partition experimental designs provide a design to model several sequential processes simultaneously. The partition design provides the investigator with an efficient design where potential cost and time constraints exist. That is, partition designs are applicable when runs are costly and a large number of variables exist in the serial process. In this paper, we present the application of partition designs using 10 factors in a simulated case study. The design and analysis procedures are discussed, as well as the benefits. Copyright © 2006 John Wiley & Sons, Ltd. [source] Ultra scale-down approach to correct dispersive and retentive effects in small-scale columns when predicting larger scale elution profilesBIOTECHNOLOGY PROGRESS, Issue 4 2009N. Hutchinson Abstract Ultra scale-down approaches represent valuable methods for chromatography development work in the biopharmaceutical sector, but for them to be of value, scale-down mimics must predict large-scale process performance accurately. For example, one application of a scale-down model involves using it to predict large-scale elution profiles correctly with respect to the size of a product peak and its position in a chromatogram relative to contaminants. Predicting large-scale profiles from data generated by small laboratory columns is complicated, however, by differences in dispersion and retention volumes between the two scales of operation. Correcting for these effects would improve the accuracy of the scale-down models when predicting outputs such as eluate volumes at larger scale and thus enable the efficient design and operation of subsequent steps. This paper describes a novel ultra scale-down approach which uses empirical correlations derived from conductivity changes during operation of laboratory and pilot columns to correct chromatographic profiles for the differences in dispersion and retention. The methodology was tested by using 1 mL column data to predict elution profiles of a chimeric monoclonal antibody obtained from Protein A chromatography columns at 3 mL laboratory- and 18.3 L pilot-scale. The predictions were then verified experimentally. Results showed that the empirical corrections enabled accurate estimations of the characteristics of larger-scale elution profiles. These data then provide the justification to adjust small-scale conditions to achieve an eluate volume and product concentration which is consistent with that obtained at large-scale and which can then be used for subsequent ultra scale-down operations. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Experiments for derived factors with application to hydraulic gear pumpsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 2 2001C. J. Sexton For experiments on mechanical products composed of several components, such as a hydraulic gear pump, conventional methods of designing and implementing factorial experiments can be impractical because of the prohibitive costs of obtaining certain components with factors set to prespecified values. A further difficulty is that often some of the factors that are believed to influence the product's performance are not features of a single component but are derived as functions of the dimensions of several components arising from the product's assembly. Experiments are proposed which use a sample of measured components to explore the influence of such derived factors. An algorithmic method for obtaining efficient designs is presented and applied to finding plans for studies on the gear pump. An experiment on the pump is described which involved both conventional and derived factors. This experiment led to new knowledge on how to improve the engineering design of the pump and, in particular, on how to improve its robustness to the varying pressures that are experienced in operation. [source] Choice experiment adaptive design benefits: a case study,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 4 2010Geoffrey N. Kerr Efficient experimental designs offer the potential to reduce required sample sizes, or to reduce confidence intervals for parameters of interest, in choice experiments. Choice experiment designs have typically addressed efficiency of utility function parameter estimates. The recently developed concept of C -efficiency recognises the salience of willingness to pay estimates rather than utility function parameters in studies that seek to put money values on attributes. C -efficiency design benefits have been illustrated in a theoretical context, but have not been tested in applied settings. This study reports a choice experiment field application that used initial responses to update statistical designs to maximise C -efficiency. Consistent with theoretical predictions, the revised design delivered significant reductions in the variance of willingness to pay estimates, illustrating that C -efficient designs can indeed decrease costs of choice experiments by reducing required sample sizes. [source] | ||||||||||