1,033 research outputs found

    Kinship as Social Capital : Economic, Social and Cultural Dimensions of Changing Kinship Relations in a Northern Vietnamese Village

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    Salemink, O.J.H.M. [Promotor]Thomese, G.C.F. [Copromotor

    A Practical Extension to the AB/BA Design

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    In this work, we take a close look at a general extension to the traditional AB/BAcrossover design that is commonly used in clinical trials to determine the effectivenessof new candidate drugs. While the traditional crossover design requires each patientin the study to be measured on both treatment A and treatment B, we consider thepossibility of additional measurements being available on each patient. This producesdesigns such as the AABB/BBAA design which has been used in previous studies.A general test statistic will be derived to test for treatment effects as well as itscorresponding power function to aid in sample size determination to aid statisticalplanning. Lastly, we explore the theoretical power of our testing procedure andcompare it to simulated power studies to verify how well sample size determinationswill work in practice

    Electrochemical copper recovery from galvanic sludge

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    The feasibility of recovering copper from electronic industrial waste mud (galvanic sludge) using a combination of leaching and electrowinning has been examined. Leaching with sulfuric acid was found to be the most efficient and cost-effective way of extracting the copper from the sludge, and the optimum acid concentration and time were determined. The copper was then extracted by electrowinning in a batch recirculation electrochemical reactor (Porocellâ„¢) employing a three-dimensional carbon felt cathode. The influence of applied current, flow rate and the presence of other metal ion contaminates on the rate and current efficiency of copper electrowinning was investigated. An analysis of the experimental data showed that the current efficiency was lower than unity even though the limiting current for copper deposition was not exceeded. This low current efficiency was attributed to the occurrence of a side reaction, most likely the reduction of dissolved oxygen or oxygen-induced corrosion. The influence of this side reaction can be minimized by operating at relatively high currents and low flow rates

    Une formulation du couplage thermo-chimio-mécanique, application aux matériaux élastomères chargés

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    Les élastomères chargés présentent un comportement dissipatif entrainant un auto-échauffement de ces matériaux sous sollicitations dynamiques. On observe un phénomène de rigidification dans les premiers cycles d'essais de fatigue. Ce phénomène s'explique par un processus de re-cuissons du matériau élastomère. Dans ce papier, nous proposons un modèle thermo-chimio-mécanique pour modéliser ce phénomène de rigidification. Notre modèle rhéologique se base sur la décomposition de la déformation en trois parties: mécanique, thermique et chimique

    Theory of Luminescent Emission in Nanocrystal ZnS:Mn with an Extra Electron

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    We consider the effect of an extra electron injected into a doped quantum dot ZnS:Mn2+ZnS:Mn^{2+}. The Coulomb interaction and the exchange interaction between the extra electron and the states of the Mn ion will mix the wavefunctions, split the impurity energy levels, break the previous selection rules and change the transition probabilities. Using this model of an extra electron in the doped quantum dot, we calculated the energy and the wavefunctions, the luminescence probability and the transition lifetime and compare with the experiments. Our calculation shows that two orders of magnitudes of lifetime shortening can occur in the transition 4T1−6A1^4T_1-^6A_1 when an extra electron is present.Comment: 15 pages, 2 Figs No change in Fig
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