11 resultados para special energy of compression and decompression

em Aston University Research Archive


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This introduction essay proposes a challenging program for researchers eager to explore factors and process mechanisms contributing to the benefits and costs individuals and groups incur from pursuing innovative approaches. With respect to individual innovation, such moderating factors might be found in the characteristics of the innovative idea, the innovator, co-workers, supervisors, the broader organizational context, and in national culture. Examples of factors that are likely to shape the beneficial and detrimental outcomes of group innovation include knowledge, skills and ability of group members, group tenure, diversity among group members, group processes (clarifying group objectives, participation, constructive management of competing perspectives), and external demands on groups. This Special Issue contains a state-of-the-science paper, three articles dealing with the benefits and costs of individual innovation, and three articles addressing the bright and dark sides of group innovation. Copyright © 2004 John Wiley & Sons, Ltd.

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Aim: N-3 fatty acids, especially eicosapentaenoic acid (EPA), may possess anticachectic properties. This trial compared a protein and energy dense supplement enriched with n-3 fatty acids and antioxidants (experimental: E) with an isocaloric isonitrogenous control supplement (C) for their effects on weight, lean body mass (LBM), dietary intake, and quality of life in cachectic patients with advanced pancreatic cancer. Methods: A total of 200 patients (95 E; 105 C) were randomised to consume two cans/day of the E or C supplement (480 ml, 620 kcal, 32 g protein ± 2.2 g EPA) for eight weeks in a multicentre, randomised, double blind trial. Results: At enrolment, patients' mean rate of weight loss was 3.3 kg/month. Intake of the supplements (E or C) was below the recommended dose (2 cans/day) and averaged 1.4 cans/day. Over eight weeks, patients in both groups stopped losing weight (Δweight E: -0.25 kg/month versus C: -0.37 kg/month; p=0.74) and LBM (ΔLBM E: +0.27 kg/month versus C: +0.12 kg/month; p=0.88) to an equal degree (change from baseline E and C, p<0.001). In view of evident non-compliance in both E and C groups, correlation analyses were undertaken to examine for potential dose-response relationships. E patients demonstrated significant correlations between their supplement intake and weight gain (r=0.50, p<0.001) and increase in LBM (r=0.33, p=0.036). Such correlations were not statistically significant in C patients. The relationship of supplement intake with change in LBM was significantly different between E and C patients (p=0.043). Increased plasma EPA levels in the E group were associated with weight and LBM gain (r=0.50, p<0.001; r=0.51, p=0.001). Weight gain was associated with improved quality of life (p<0.01) only in the E group. Conclusion: Intention to treat group comparisons indicated that at the mean dose taken, enrichment with n-3 fatty acids did not provide a therapeutic advantage and that both supplements were equally effective in arresting weight loss. Post hoc dose-response analysis suggests that if taken in sufficient quantity, only the n-3 fatty acid enriched energy and protein dense supplement results in net gain of weight, lean tissue, and improved quality of life. Further trials are required to examine the potential role of n-3 enriched supplements in the treatment of cancer cachexia.

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The compaction behaviour of powders with soft and hard components is of particular interest to the paint processing industry. Unfortunately, at the present time, very little is known about the internal mechanisms within such systems and therefore suitable tests are required to help in the interpretative process. The TRUBAL, Distinct Element Method (D.E.M.) program was the method of investigation used in this study. Steel (hard) and rubber (soft) particles were used in the randomly-generated, binary assemblies because they provided a sharp contrast in physical properties. For reasons of simplicity, isotropic compression of two-dimensional assemblies was also initially considered. The assemblies were first subject to quasi-static compaction, in order to define their behaviour under equilibrium conditions. The stress-strain behaviour of the assemblies under such conditions was found to be adequately described by a second-order polynomial expansion. The structural evolution of the simulation assemblies was also similar to that observed for real powder systems. Further simulation tests were carried out to investigate the effects of particle size on the compaction behaviour of the two-dimensional, binary assemblies. Later work focused on the quasi-static compaction behaviour of three-dimensional assemblies, because they represented more realistic particle systems. The compaction behaviour of the assemblies during the simulation experiments was considered in terms of percolation theory concepts, as well as more familiar macroscopic and microstructural parameters. Percolation theory, which is based on ideas from statistical physics, has been found to be useful in the interpretation of the mechanical behaviour of simple, elastic lattices. However, from the evidence of this study, percolation theory is also able to offer a useful insight into the compaction behaviour of more realistic particle assemblies.

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This thesis investigates the cost of electricity generation using bio-oil produced by the fast pyrolysis of UK energy crops. The study covers cost from the farm to the generator’s terminals. The use of short rotation coppice willow and miscanthus as feedstocks was investigated. All costs and performance data have been taken from published papers, reports or web sites. Generation technologies are compared at scales where they have proved economic burning other fuels, rather than at a given size. A pyrolysis yield model was developed for a bubbling fluidised bed fast pyrolysis reactor from published data to predict bio-oil yields and pyrolysis plant energy demands. Generation using diesel engines, gas turbines in open and combined cycle (CCGT) operation and steam cycle plants was considered. The use of bio-oil storage to allow the pyrolysis and generation plants to operate independently of each other was investigated. The option of using diesel generators and open cycle gas turbines for combined heat and power was examined. The possible cost reductions that could be expected through learning if the technology is widely implemented were considered. It was found that none of the systems analysed would be viable without subsidy, but with the current Renewable Obligation Scheme CCGT plants in the 200 to 350 MWe range, super-critical coal fired boilers co-fired with bio-oil, and groups of diesel engine based CHP schemes supplied by a central pyrolysis plant would be viable. It was found that the cost would reduce with implementation and the planting of more energy crops but some subsidy would still be needed to make the plants viable.

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It is a great pleasure to be Guest Editor for this issue – I hope that the papers which are included will be stimulating and support you in your ongoing research activities. A number of guiding principles were adopted in selecting the papers for inclusion in this issue. Firstly, the papers cover a wide range of logistics and supply chain management (SCM) topics. This is a reflection of the evolution of the field in recent years. In terms of the “buy-make-store-move-sell” model of SCM all the main constituent areas are addressed. Secondly, it is important that the conference issue of this Journal reflects the emphasis and content of the conference itself. I have tried to achieve this in terms of the papers included. One interesting point to note is that outsourcing is a theme which is a major issue in a number of papers. This reflects the increasing importance of this issue to organisations of all kinds and sizes. Economic globalisation and the trend towards vertical disintegration of supply chain architectures have sharpened the focus on outsourcing as a key element of supply chain strategy. The need to move beyond the notion that sourcing of certain activities can be some kind of panacea in evident from the relevant contributions. Thirdly, the LRN Annual Conference has become a more international event in recent years...the number of delegates and papers presented from outside the UK has continued to grow. The papers collected in this issue reflect this internationalization. Two papers are worthy of particular comment from an LRN perspective. The contribution by Jaafar and Rafiq has been developed from the submission which won the best paper prize at the LRN 2004 event. The paper by Pettit and Beresford is based on research which was supported by LRN seed corn funding. It was developed form the final report on this work submitted to CITL (UK) via the LRN. The seed corn funding is an important mechanism whereby the LRN supports research in innovative aspects of logistics in UK universities. In many ways, the LRN2004 event in Dublin seems like a long time ago. From my point of view it was one of the most professionally rewarding activities in which I have been involved in my career. It was a time to meet old friends and new and to keep abreast of the multitude of interesting projects being undertaken in over 20 countries. There are too many people to thank for the smooth running of the event. However, my colleague John Mee does warrant a special mention. His logistical skills were seriously put to the test in the weeks and months leading up to September 9th. 2004. I want to acknowledge his particular contribution to the success of the event. Since then we have had the 2005 event at the University of Plymouth. This was again a great opportunity to network with colleagues and many congratulations are due to John Dinwoodie and his team. We now look forward to LRN 2006 in Newcastle...form my part I hope and trust that this issue provides some useful perspectives and insights into the range of topics addressed.

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We present three jargonaphasic patients who made phonological errors in naming, repetition and reading. We analyse target/response overlap using statistical models to answer three questions: 1) Is there a single phonological source for errors or two sources, one for target-related errors and a separate source for abstruse errors? 2) Can correct responses be predicted by the same distribution used to predict errors or do they show a completion boost (CB)? 3) Is non-lexical and lexical information summed during reading and repetition? The answers were clear. 1) Abstruse errors did not require a separate distribution created by failure to access word forms. Abstruse and target-related errors were the endpoints of a single overlap distribution. 2) Correct responses required a special factor, e.g., a CB or lexical/phonological feedback, to preserve their integrity. 3) Reading and repetition required separate lexical and non-lexical contributions that were combined at output.

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Extensive numerical investigations are undertaken to analyze and compare, for the first time, the performance, techno-economy, and power consumption of three-level electrical Duobinary, optical Duobinary, and PAM-4 modulation formats as candidates for high-speed next-generation PONs supporting downstream 40 Gb/s per wavelength signal transmission over standard SMFs in C-band. Optimization of transceiver bandwidths are undertaken to show the feasibility of utilizing low-cost and band-limited components to support next-generation PON transmissions. The effect of electro-absorption modulator chirp is examined for electrical Duobinary and PAM-4. Electrical Duobinary and optical Duobinary are powerefficient schemes for smaller transmission distances of 10 km SMFs and optical Duobinary offers the best receiver sensitivity albeit with a relatively high transceiver cost. PAM-4 shows the best power budget and costefficiency for larger distances of around 20 km, although it consumes more power. Electrical Duobinary shows the best trade-off between performance, cost and power dissipation.