85,615 research outputs found
Hydraulic fluid interaction servovalve
Fluidic vortex valves used as fluid control elements in hydraulic servoactuator control syste
Implementing the market approach to enterprise support - an evaluation of ten matching grant schemes
Developing viable new business is critical to recovery, and long-term growth, especially in transition economies. There has been a long history of public support of enterprise development, starting with centralized state agency initiatives, but moving more recently to decentralized instruments for development of the business services market. The window of time during which the benefits of intervention are likely to be greatest: when a market is in its infancy, and its development is constrained by uncertainty, and lack of information. Interventions for enterprise support should be demand-responsive, and flexibly organized. In some circumstances, centralized assistance may still be effective, but it is generally better to use competitive private service providers responding to enterprises'changing needs. The main task is to stimulate the private services sector, improving its capacity to respond to the demands of new, and expanding private enterprises. Support for enterprises has tended to be either free, or heavily subsidized. But such subsidies can be justified only if interventions efficiently supply goods. Providing technical, and management know-how can be a public good if it generates externalities- if, for example, know-how benefits can be disseminated at proportionately low additional cost. Any subsidy for an intervention should be temporary, and should be phased out when the main objective of intervention is achieved - that is, when the market takes off. Grants should generally be for know-how, not for equipment. There may be a case for unbundling the know-how component of loans (including feasibility studies, and follow-up expert services) for grant funding. A package combining loans and grants - through a single financial institution, or through separate institutions - may work provided safeguards can be put in place to prevent perverse use of grants. The matching grant model, which is used increasingly in the World Bank, and elsewhere, is one solution - but it must be justified, and carefully designed. After evaluating ten matching grant funds, the author concludes that performance is mixed. Best practice models are needed. Ensuring economic benefits requires proactive management, with clear objectives of market facilitation ("making a market"). And it requires a balance between rapid grant approval procedures, and careful selection of services for grants.Economic Theory&Research,Decentralization,Enterprise Development&Reform,Environmental Economics&Policies,Banks&Banking Reform,Health Economics&Finance,Banks&Banking Reform,Economic Theory&Research,Environmental Economics&Policies,ICT Policy and Strategies
Evaluation of battery models for prediction of electric vehicle range
Three analytical models for predicting electric vehicle battery output and the corresponding electric vehicle range for various driving cycles were evaluated. The models were used to predict output and range, and then compared with experimentally determined values determined by laboratory tests on batteries using discharge cycles identical to those encountered by an actual electric vehicle while on SAE cycles. Results indicate that the modified Hoxie model gave the best predictions with an accuracy of about 97 to 98% in the best cases and 86% in the worst case. A computer program was written to perform the lengthy iterative calculations required. The program and hardware used to automatically discharge the battery are described
Technique for pinpointing submicron particles in the electron microprobe
Series of electron micrographs at successively lower magnifications can localize the substrate area sufficiently for a particle to be picked up by the beam of the electron microprobe. This approach could be modified to apply to fractographic studies, particularly of oxidation products stripped from fractures
Impacts of farming practice within organic farming systems on below-ground ecology and ecosystem function
Maintaining ecosystem function is a key issue for sustainable farming systems which contribute broadly to global ecosystem health. A focus simply on the diversity of belowground organisms is not sufficient and there is a need to consider the contribution of below-ground biological processes to the maintenance and enhancement of soil function and ecosystem services. A critical literature review on the impacts of land management practices on below-ground ecology and function shows that farm management practices can have a major impact. A particular challenge for organic farming systems is to explore to what extent reduced tillage can be adopted to the benefit of below-ground ecology without critically upsetting the whole farm management balance
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