80,935 research outputs found
The National Geothermal Energy Research Program
The continuous demand for energy and the concern for shortages of conventional energy resources have spurred the nation to consider alternate energy resources, such as geothermal. Although significant growth in the one natural steam field located in the United States has occurred, a major effort is now needed if geothermal energy, in its several forms, is to contribute to the nation's energy supplies. From the early informal efforts of an Interagency Panel for Geothermal Energy Research, a 5-year Federal program has evolved whose objective is the rapid development of a commercial industry for the utilization of geothermal resources for electric power production and other products. The Federal program seeks to evaluate the realistic potential of geothermal energy, to support the necessary research and technology needed to demonstrate the economic and environmental feasibility of the several types of geothermal resources, and to address the legal and institutional problems concerned in the stimulation and regulation of this new industry
Thin wire pointing method
A method is described for forming sharp tips on thin wires, in particular phosphor bronze wires of diameters such as one-thousandth inch used to contact micron size Schottky barrier diodes, which enables close control of tip shape and which avoids the use of highly toxic solutions. The method includes dipping an end of a phosphor bronze wire into a dilute solution of sulfamic acid and applying a current through the wire to electrochemically etch it. The humidity in the room is controlled to a level of less than 50%, and the voltage applied between the wire and another electrode in the solutions is a half wave rectified voltage. The current through the wire is monitored, and the process is stopped when the current falls to a predetermined low level
Why did British Electricity Prices Fall after 1998?
In an attempt to reduce high electricity prices in England and Wales the government has reduced concentration among generators and introduced New Electricity Trading Arrangements (NETA). Econometric analysis on monthly data from April 1996 to September 2002 implies support for two conflicting hypotheses. On a static view, increases in competition and the capacity margin were chiefly responsible for the fall in prices. If generators had been tacitly colluding before NETA, however, the impending change in market rules might have changed their behaviour a few months before the abolition of the Pool. That view implies that NETA reduced prices.Electricity, market power, concentration, market rules
Components of Manufacturing Inventories
This paper presents a structural model of production and inventory accumulation based on the hypothesis of cost minimization. It differs from previous attempts in several respects. First, it integrates the analysis of input inventories with output inventories, treating the two stocks separately. Second, it distinguishes between temporary and permanent fluctuations in sales as they are anticipated by the industry. Third, it allows for a more general structure of adjustment costs, and in particular for a cost changing the production level rather than only for deviations of the production level from a fixed target. Empirically, there are three principal conclusions. This model performs much better than those with no cost of production adjustment allowed. Disaggregation of inventories provides significant insights into the dynamics of the adjustment process. However, the restrictions on our model implied by the continuous-time stochastic control theory that we utilize are rejected by the data. We believe that a more disaggregated specification or a more detailed econometric treatment of the discrete-time nature of the observations would avoid this difficulty.
Identification of the YfgF MASE1 domain as a modulator of bacterial responses to aspartate
Complex 3'-5'-cyclic diguanylic acid (c-di-GMP) responsive regulatory networks that are modulated by the action of multiple diguanylate cyclases (DGC; GGDEF domain proteins) and phosphodiesterases (PDE; EAL domain proteins) have evolved in many bacteria. YfgF proteins possess a membrane-anchoring domain (MASE1), a catalytically inactive GGDEF domain and a catalytically active EAL domain. Here, sustained expression of the Salmonella enterica spp. Enterica ser. Enteritidis YfgF protein is shown to mediate inhibition of the formation of the aspartate chemotactic ring on motility agar under aerobic conditions. This phenomenon was c-di-GMP-independent because it occurred in a Salmonella strain that lacked the ability to synthesize c-di-GMP and also when PDE activity was abolished by site-directed mutagenesis of the EAL domain. YfgF-mediated inhibition of aspartate chemotactic ring formation was impaired in the altered redox environment generated by exogenous p-benzoquinone. This ability of YfgF to inhibit the response to aspartate required a motif, (213)Lys-Lys-Glu(215), in the predicted cytoplasmic loop between trans-membrane regions 5 and 6 of the MASE1 domain. Thus, for the first time the function of a MASE1 domain as a redox-responsive regulator of bacterial responses to aspartate has been shown
An investigation into the approaches used by western medical herbalists for the therapeutic management of osteoarthritis
Osteoarthritis affects people from middle age onwards, an occurrence likely to increase as average age of the population rises. Physical aspects of the condition are accompanied by increased all-cause mortality and morbidity. Use of pharmaceutical medication may be unhelpful or undesired.
Much research focuses on the use of single herbs contrary to current Western herbal practice of combining several herbs with diet and lifestyle advice. This research aimed to explore this knowledge gap by eliciting details of strategies used to manage osteoarthritis.
A qualitative approach using audio recorded, semi-structured interviews, with additional questions to define practitioner demographics was used for the study. The study sample comprised eight herbalists, all members of either the National Institute of Medical Herbalists or the College of Practitioners of Phytotherapy, each with a minimum two years in practice and experience of treating osteoarthritis. The resulting data was analysed using thematic analysis.
Practitioner demographics revealed a range of time in practice, choice of practice location and training establishment. Analysis of the interviews elicited five themes; patient picture, practitionersâ therapeutic strategy, herbal treatment, non-herbal treatment and practitionersâ perceived treatment outcomes. A core group of 11 frequently used herbs was identified with a further 33 herbs being used less often. All practitioners prescribed remedies internally with most also using topical treatments.
In conclusion, the patient picture was a diverse one with no clear picture of a âtypicalâ patient with osteoarthritis; however, consensus between practitionersâ treatment approaches, both herbal and non-herbal was high. Selected herbal remedies were consistent with literature found on some single herb studies. All herbalists were of the opinion that the herbal approach to osteoarthritis had a positive effect on the condition. These outcomes were usually perceived by reduced intake of painkillers and observing improved mobility or reduced inflammation
Assessment of casting filling by modeling surface entrainment events using CFD
The reliability of cast components is dependent on the quality of the casting process. During this highly transient filling phase the prevention of free surface turbulence and consequential oxide entrainment is critical to ensure the mechanical integrity of the component. Past research has highlighted a number of events that lead to entrainment of surface oxides. Using FLOW-3D, flow structures that result in surface entrainment events have been simulated and an algorithm developed that allows entrainment and defect motion to be tracked. This enables prediction of the quantity and motion of oxide film generated from each event. The algorithm was tested experimentally and compared to experimental data from previously published work. A quantitative criterion is proposed to assess the damage of each type of event. Complete running systems have also been studied to understand how they could be assessed for quality of filling based on the flows within them
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