983 resultados para Isostatic pressing.
Resumo:
One of the most pressing issues facing the global conservation community is how to distribute limited resources between regions identified as priorities for biodiversity conservation(1-3). Approaches such as biodiversity hotspots(4), endemic bird areas(5) and ecoregions(6) are used by international organizations to prioritize conservation efforts globally(7). Although identifying priority regions is an important first step in solving this problem, it does not indicate how limited resources should be allocated between regions. Here we formulate how to allocate optimally conservation resources between regions identified as priorities for conservation - the 'conservation resource allocation problem'. Stochastic dynamic programming is used to find the optimal schedule of resource allocation for small problems but is intractable for large problems owing to the curse of dimensionality(8). We identify two easy- to- use and easy- to- interpret heuristics that closely approximate the optimal solution. We also show the importance of both correctly formulating the problem and using information on how investment returns change through time. Our conservation resource allocation approach can be applied at any spatial scale. We demonstrate the approach with an example of optimal resource allocation among five priority regions in Wallacea and Sundaland, the transition zone between Asia and Australasia.
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Early work on sea-levels in southwest Australia claimed to recognise a Holocene sea-level highstand which was not seen in better known sea-level records elsewhere at the time. More recent work has confirmed that a mid-Holocene highstand Occurred about 6 kyr ago. As new data on oscillating sea-levels from the region have recently been published, a high continuity, precisely dated and accurately surveyed record was obtained from emergent coral pavements in the leeward Houtman Abrolhos Islands (Serventy Island), a tectonically stable region from where good-quality Holocene sea-level data have been previously obtained from corals. From the mid-Holocene highstand ca. 7 U/Th kyr ago, sea-level declined linearly during the remainder of the Holocene as the carbonate platform prograded leewards. Hydro-isostatic controls are probably significant in the record. (c) 2005 Elsevier Ltd and INQUA. All rights reserved.
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A obesidade é uma doença crônica que vem acometendo, progressivamente, cada vez mais pessoas no mundo. Por ser uma patologia de difícil controle que favorece a eclosão de outros agravos à saúde, é premente a necessidade de realização de pesquisas que possam contribuir para o aperfeiçoamento dos tratamentos, bem como para a melhoria da qualidade de vida e eficácia adaptativa. Sendo assim, a presente pesquisa visou avaliar a percepção da qualidade de vida (QV), a eficácia adaptativa (EDAO) e o funcionamento global (AGF) de pessoas com obesidade, relacionando os resultados obtidos na avaliação da percepção da QV com os da eficácia adaptativa, bem como aos do funcionamento global (AGF). Para tanto, utilizou-se o questionário WHOQOL-100 versão em português para avaliação da percepção de qualidade de vida, a Entrevista Diagnóstica Preventiva Escala Diagnóstica Adaptativa Operacionalizada (EDAO) para a eficácia adaptativa e a Escala de Avaliação do Funcionamento Global (AGF) para o funcionamento global. Este estudo contou com a participação de trinta mulheres obesas (Índice de Massa Corporal IMC >=30 kg/m2), com idade média de 52,33 anos, que utilizavam os serviços de um ambulatório situado na região do Grande ABC, estado de SP. A maioria das participantes se encontrava no grau I de obesidade - 46,70%, situava-se no grau II 33,30% e 20,00% no grau III. O aumento de peso da maioria teve início nas gestações (43,30%), o segundo período onde ocorreu o início do descontrole do peso corporal foi entre os 40 aos 50 anos (20,00%). Na avaliação geral da QV, observou-se que no domínio VI Aspectos Espirituais/Religião/Crenças Pessoais foi encontrado o maior escore médio (16,17 - DP=2,95 [equivalente a 80,83% do escore máximo que poderia ser obtido]), comparando-o com os demais domínios avaliados. Em oposição, o domínio I Físico foi o que apresentou o menor escore médio (11,77 - DP=2,78 - 58,83%). Todas as participantes se encontravam em ineficácia adaptativa: Grupo 2 Ineficaz Leve (26,7%), no Grupo 3 Ineficaz Moderada (33,3%) e no Grupo 4 Ineficaz Severa (30,0%). Quanto à avaliação do funcionamento global (AGF), notou-se que 36,67% se situavam no intervalo entre 51-60 pontos. 23,33% das participantes no intervalo entre 31-50 pontos. Apenas 23,33% tiveram pontuação acima de 70 pontos. Relacionando os resultados das avaliações, foram encontradas correlações fortes, positivas e significativas entre a avaliação da percepção de qualidade de vida, da eficácia adaptativa e do funcionamento Global.
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O presente estudo teve como objetivo avaliar aspectos psicofisiológicos da ansiedade em particular a atenção e a percepção da passagem do tempo. Foi aplicada a escala psicométrica de ansiedade do IDATE em 180 alunos do curso de Educação Física da Universidade de São Paulo em sala de aula. Foram selecionados 15 voluntários mais ansiosos e 15 menos ansiosos foi considerado o IDATE traço por apresentar características mais constantes da ansiedade. O experimento 1 foi a tarefa de Tempo Espontâneo onde os participantes deviam bater o dedo no botão A do joystick da forma mais regular e precisa possível por um minuto. Já no experimento 2 os participantes foram orientados a responder o mais rápido possível ao surgimento do estimulo (ponto branco 0,4 grau) com uma luminância de 80 cd/m contra um fundo cinza pressionando o botão A do joystick com qualquer dedo da mão dominante (TRS). Os estímulos eram apresentados randomicamente por 82 posições diferentes na tela do computador. Após tratamento dos dados e analise estatística, o estudo de caráter geral e exploratório apresentado aqui mostra tendências, mas não correlações significativas entre as medidas. Alguns dados, no entanto, chamam a atenção e devem ser considerados no planejamento de experimentos futuros.
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Of the myriad of pressing topics current in medical law and ethics, the issue of informed consent appears to be the ‘plainer sibling’. The decision by Cranston J in Birch v UCL Hospital NHS Foundation Trust in 2008 has brought into sharp relief that which many commentators already held to be true. Far from being the ‘plainer sibling’ when weighed against other prominent issues in medical law and ethics, the doctrine of informed consent, is one of the most significant principles to emerge in recent years.
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For many decades, the Kingdom of Saudi Arabia has been widely known for being a reliable oil exporter. This fact, however, has not exempted it from facing significant domestic energy challenges. One of the most pressing of these challenges involves bridging the widening electricity supply-demand gap where, currently, the demand is growing at a very fast rate. One crucial means to address this challenge is through delivering power supply projects with maximum efficiency. Project delivery delay, however, is not uncommon in this highly capital-intensive industry, indicating electricity supplies are not coping with the demand increases. To provide a deeper insight into the challenges of project implementation and efficient practice, this research adopts a pragmatic approach by triangulating literature, questionnaires and semi-structured interviews. The research was conducted in the Saudi Arabian power supply industry – Western Operating Area. A total of 105 usable questionnaires were collected, and 28 recorded, semi-structured interviews were conducted, analysed and synthesised to produce a conceptual model of what constitutes the project implementation challenges in the investigated industry. This was achieved by conducting a comprehensive ranking analysis applied to all 58 identified and surveyed factors which, according to project practitioners in the investigated industry, contribute to project delay. 28 of these project delay factors were selected as the "most important" ones. Factor Analysis was employed to structure these 28 most important project delay factors into the following meaningful set of 7 project implementation challenges: Saudi Electricity Company's contractual commitments, Saudi Electricity Company's communication and coordination effectiveness, contractors' project planning and project control effectiveness, consultant-related aspects, manpower challenges and material uncertainties, Saudi Electricity Company's tendering system, and lack of project requirements clarity. The study has implications for industry policy in that it provides a coherent assessment of the key project stakeholders' central problems. From this analysis, pragmatic recommendations are proposed that, if enacted, will minimise the significance of the identified problems on future project outcomes, thus helping to ensure the electricity supply-demand gap is diminished.
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Orally disintegrating tablets (ODTs) offer many advantages over the conventional oral dosage forms in terms of convenience and ease of use. Over the last decade, substantial advances in the formulation of ODTs have been achieved in academia and industry that resulted in the emerging of a large number of patents. The aim of this review is to summarise the most recent patents in ODT formulations and highlight their motivations, inventive steps and significances in the development of ODT formulations. Five major techniques have been applied in manufacturing of ODTs, namely conventional tablet press, moulding, freeze drying, tablet loading and pulverization, with majority of the patents dedicated to the use of conventional tablet pressing. The patents have addressed various issues concerning the manufacturing of robust and practical ODT formulations by disclosing new manufacturing techniques, advantageous materials, and innovative formulation steps. However, future developments are required to reduce the cost and widening the application of the new manufacturing techniques, while simplifying and shortening the formulation steps will be crucial in the well established ones.
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The main objective of this work was to examlne the various stages of the production of industrial laminates based on phenol-formaldehyde resins, with a view of suggesting ways of improving the process economics and/or the physical properties of the final product. Aspects of impregnation, drying, and lamination were investigated. The resins used in all experiments were ammonia-catalysed. Work was concentrated on the lamination stage since this is a labour intensive activity. Paper-phenolic lay-ups were characterised in terms of the temperatures experienced during cure, and a shorter cure-cycle is proposed, utilising the exothermic heat produced during pressing of 25.5 mm thick lay-ups. Significant savings in production costs and improvements in some of the physical properties have been achieved. In particular, water absorption has been reduced by 43-61%. Work on the drying stage has shown that rapid heating of the wet impregnated substrate results in resin solids losses. Drying at lower temperatures by reducing the driving force leads to more resin (up to 6.5%) being retained by the prepregs and therefore more effective use of an expensive raw material. The impregnation work has indicated that residence times above 6 seconds in the varnish bath enhance the insulation resistance of the final product, possibly due to improved resin distribution and reduction in water absorption. In addition, a novel process which involves production of laminates by in situ polymerisation of the phenolic resin on the substrate has been examined. Such a process would eliminate the solvent recovery plant - a necessary stage in current industrial processes. In situ polymerisation has been shown to be chemically feasible.
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Soil erosion is one of the most pressing issues facing developing countries. The need for soil erosion assessment is paramount as a successful and productive agricultural base is necessary for economic growth and stability. In Ghana, a country with an expanding population and high potential for economic growth, agriculture is an important resource; however, most of the crop production is restricted to low technology shifting cultivation agriculture. The high intensity seasonal rainfall coincides with the early growing period of many of the crops meaning that plots are very susceptible to erosion, especially on steep sided valleys in the region south of Lake Volta. This research investigated the processes of soil erosion by rainfall with the aim of producing a sediment yield model for a small semi-agricultural catchment in rural Ghana. Various types of modelling techniques were considered to discover those most applicable to the sub-tropical environment of Southern Ghana. Once an appropriate model had been developed and calibrated, the aim was to look at how to enable the scaling up of the model using sub-catchments to calculate sedimentation rates of Lake Volta. An experimental catchment was located in Ghana, south west of Lake Volta, where data on rainstorms and the associated streamflow, sediment loads and soil data (moisture content, classification and particle size distribution) was collected to calibrate the model. Additional data was obtained from the Soil Research Institute in Ghana to explore calibration of the Universal Soil Loss Equation (USLE, Wischmeier and Smith, 1978) for Ghanaian soils and environment. It was shown that the USLE could be successfully converted to provide meaningful soil loss estimates in the Ghanaian environment. However, due to experimental difficulties, the proposed theory and methodology of the sediment yield model could only be tested in principle. Future work may include validation of the model and subsequent scaling up to estimate sedimentation rates in Lake Volta.
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Bilateral corneal blindness represents a quarter of the total blind, world-wide. The artificial cornea in assorted forms, was developed to replace opaque non-functional corneas and to return sight in otherwise hopeless cases that were not amenable to corneal grafts; believed to be 2% of corneal blind. Despite technological advances in materials design and tissue engineering no artificial cornea has provided absolute, long-term success. Formidable problems exist, due to a combination of unpredictable wound healing and unmanageable pathology. To have a solid guarantee of reliable success an artificial cornea must possess three attributes: an optical window to replace the opaque cornea; a strong, long term union to surrounding ocular tissue; and the ability to induce desired host responses. A unique artificial cornea possesses all three functional attributes- the Osteo-odonto-keratoprosthesis (OOKP). The OOKP has a high success rate and can survive for up to twenty years, but it is complicated both in structure and in surgical procedure; it is expensive and not universally available. The aim of this project was to develop a synthetic substitute for the OOKP, based upon key features of the tooth and bone structure. In doing so, surgical complexity and biological complications would be reduced. Analysis of the biological effectiveness of the OOKP showed that the structure of bone was the most crucial component for implant retention. An experimental semi-rigid hydroxyapatite framework was fabricated with a complex bone-like architecture, which could be fused to the optical window. The first method for making such a framework, was pressing and sintering of hydroxyapatite powders; however, it was not possible to fabricate a void architecture with the correct sizes and uniformity of pores. Ceramers were synthesised using alternative pore forming methods, providing for improved mechanical properties and stronger attachment to the plastic optical window. Naturally occurring skeletal structures closely match the structural features of all forms of natural bone. Synthetic casts were fabricated using the replamineform process, of desirable natural artifacts, such as coral and sponges. The final method of construction by-passed ceramic fabrication in favour of pre-formed coral derivatives and focused on methods for polymer infiltration, adhesion and fabrication. Prototypes were constructed and evaluated; a fully penetrative synthetic OOKP analogue was fabricated according to the dimensions of the OOKP. Fabrication of the cornea shaped OOKP synthetic analogue was also attempted.
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Britain's sea and flood defences are becoming increasingly aged and as a consequence, more fragile and vulnerable. As the government's philosophy on resources shifts against the use of prime quarried and dredged geo-materials, the need to find alternative bulk materials to bolster Britain's prone defences becomes more pressing. One conceivable source for such a material is colliery waste or minestone. Although a plethora of erosion-abrasion studies have been carried out on soils and soil-cements, very little research has been undertaken to determine the resistance of minestone and its cement stabilized form to the effects of water erosion. The thesis reviews the current extent to which soil-cements, minestone and cement stabilized minestone (CSM) have been employed for hydraulic construction projects. A synopsis is also given on the effects of immersion on shales, mudstones and minestone, especially with regard to the phenomena of slaking. A laboratory study was undertaken featuring a selection of minestones from several British coalfields. The stability of minestone and CSM in sea water and distilled water was assessed using slaking tests and immersion monitoring and the bearing on the use of these materials for hydraulic construction is discussed. Following a review of current erosion apparatus, the erosion/abrasion test and rotating cylinder device were chosen and employed to assess the erosion resistance of minestone and CSM. Comparison was made with a sand mix designed to represent a dredged sand, the more traditional, bulk hydraulic construction material. The results of the erosion study suggest that both minestone and CSM were more resistant to erosion and abrasion than equivalently treated sand mixes. The greater resistance of minestone to the agents of erosion and abrasion is attributed to several factors including the size of the particles, a greater degree of cement bonding and the ability of the minestone aggregate to absorb, rather than transmit shock waves produced by impacting abrasive particles. Although minestone is shown to be highly unstable when subjected to cyclic changes in its moisture content, the study suggests that even in an intertidal regime where cyclic immersion does takes place, minestone will retain sufficient moisture within its fabric to prevent slaking from taking place. The slaking study reveals a close relationship between slaking susceptibility and total pore surface area as revealed by porosimetry. The immersion study shows that although the fabric of CSM is rapidly attacked in sea water, a high degree of the disruption is associated with the edges and corners of samples (ie. free surface) while the integrity of the internal fabric remains relatively intact. CSM samples were shown to be resilient when subjected to immersion in distilled water. An overall assessment of minestone and CSM would suggest that with the implementation of judicious selection and appropriate quality control they could be used as alternative materials for flood and sea defences. It is believed, that even in the harsh regime of a marine environment, CSM could be employed for temporary and sacrificial schemes.
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The development of cobalt molybdenum and cobalt tungsten brush plating electrolytes is described. Their optimum compositions and operating conditions for commercial applications have been determined. The effects of composition, pH, applied voltage, stylus speed and pressure upon deposit composition and efficiency have been investigated. Transmission and Scanning Electron Microscopy have been employed to study the cobalt alloy deposits produced. Evaluation of the wear resistant properties of the cobalt alloys developed in this work was carried out in the laboratory using a pin and disc technique and a simulated hot forging test, and by industrial trials involving the "on site" plating of hot forging dies and cold pressing tools. It was concluded that the electrolytes developed in tl1is work enabled cobalt alloys containing 6% Mo or 8% W to be deposited at 17-20V. Brush plated cobalt deposits possessed a mixed CPU and FCC crystallographic structure at room temperature. The application of 13µm of either of the cobalt alloys resulted in improved wear performance in both pin and disc and simulated hot forging tests. The results of the industrial trials indicated that by the use of these alloys, the life of hot forging dies may be increased by 20-100%. A commercial forging organisation is using electrolytes developed in this work to coat dies prior to forging nimonic alloys. Reductions in forging temperature and improved forging qualities have been reported. Cold pressing tools coated with the alloys showed a reduced tendency to "pick-up" and scoring of the pressed panels. Reports of a reduced need for lubrication of panels before pressing have also been received.
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This study investigates the discursive patterns of interactions between police interviewers and women reporting rape in significant witness interviews. Data in the form of video recorded interviews were obtained from a UK police force for the purposes of this study. The data are analysed using a multi-method approach, incorporating tools from micro-sociology, Conversation Analysis and Discursive Psychology, to reveal patterns of interactional control, negotiation, and interpretation. The study adopts a critical approach, which is to say that as well as describing discursive patterns, it explains them in light of the discourse processes involved in the production and consumption of police interview talk, and comments on the relationship between these discourse processes and the social context in which they occur. A central focus of the study is how interviewers draw on particular interactional resources to shape interviewees? accounts in particular ways, and this is discussed in relation to the institutional role of the significant witness interview. The discussion is also extended to the ways in which mainstream rape ideology is both reflected in, and maintained by, the discursive choices of participants. The findings of this study indicate that there are a number of issues to be addressed in terms of the training currently offered to officers at Level 2 of the Professionalising Investigation Programme (PIP) (NPIA, 2009) who intend to conduct significant witness interviews. Furthermore, a need is identified to bring the linguistic and discursive processes of negotiation and transformation identified by the study to the attention of the justice system as a whole. This is a particularly pressing need in light of judicial reluctance to replace written witness statements, the current „end product? of significant witness interviews, with the video recorded interview in place of direct examination in cases of rape.
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While the need for humanising education is pressing in neoliberal societies, the conditions for its possibility in formal institutions have become particularly cramped. A constellation of factors – the strength of neoliberal ideologies, the corporatisation of universities, the conflation of human freedom with consumer satisfaction, and a wider crisis of hope in the possibility or desirability of social change – make it difficult to apply classical theories of subject-transformation to new work in critical pedagogy. In particular, the growth of interest in pedagogies of comfort (as illustrated in certain forms of ‘therapeutic’ education and concerns about student ‘satisfaction’) and resistance to critical pedagogies suggest that subjectivty has become a primary site of political struggle in education. However, it can no longer be assumed that educators can (or should) liberate students’ repressed desires for ‘humanisation’ by politicising curricula, pedagogy or institutions. Rather, we must work to understand the new meanings and affective conditions of critical subjectivity itself. Bringing critical theories of subject transformation together with new work on ‘pedagogies of discomfort’, I suggest we can create new ways of opening up possibilities for critical education that respond to neoliberal subjectivities without corresponding to or affirming them.
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Drying is an important unit operation in process industry. Results have suggested that the energy used for drying has increased from 12% in 1978 to 18% of the total energy used in 1990. A literature survey of previous studies regarding overall drying energy consumption has demonstrated that there is little continuity of methods and energy trends could not be established. In the ceramics, timber and paper industrial sectors specific energy consumption and energy trends have been investigated by auditing drying equipment. Ceramic products examined have included tableware, tiles, sanitaryware, electrical ceramics, plasterboard, refractories, bricks and abrasives. Data from industry has shown that drying energy has not varied significantly in the ceramics sector over the last decade, representing about 31% of the total energy consumed. Information from the timber industry has established that radical changes have occurred over the last 20 years, both in terms of equipment and energy utilisation. The energy efficiency of hardwood drying has improved by 15% since the 1970s, although no significant savings have been realised for softwood. A survey estimating the energy efficiency and operating characteristics of 192 paper dryer sections has been conducted. Drying energy was found to increase to nearly 60% of the total energy used in the early 1980s, but has fallen over the last decade, representing 23% of the total in 1993. These results have demonstrated that effective energy saving measures, such as improved pressing and heat recovery, have been successfully implemented since the 1970s. Artificial neural networks have successfully been applied to model process characteristics of microwave and convective drying of paper coated gypsum cove. Parameters modelled have included product moisture loss, core gypsum temperature and quality factors relating to paper burning and bubbling defects. Evaluation of thermal and dielectric properties have highlighted gypsum's heat sensitive characteristics in convective and electromagnetic regimes. Modelling experimental data has shown that the networks were capable of simulating drying process characteristics to a high degree of accuracy. Product weight and temperature were predicted to within 0.5% and 5C of the target data respectively. Furthermore, it was demonstrated that the underlying properties of the data could be predicted through a high level of input noise.