112 resultados para PRESSURES


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dhaka cheese is a semihard artisanal variety made mainly from bovine milk, using very simple pressing methods. Experimental cheeses were pressed at gauge pressures up to 31 kPa for 12 h at 24 °C and 70% RH. These cheeses were subsequently examined for their compositional, textural and rheological properties plus their microstructures investigated by confocal laser microscopy. The cheese pressed at 15.6 kPa was found to have the best compositional and structural properties.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The study of stable isotopes surviving in human bone is fast becoming a standard response in the analysis of cemeteries. Reviewing the state of the art for Roman Britain, the author shows clear indications of a change in diet (for the better) following the Romanisation of Iron Age Britain—including more seafood, and more nutritional variety in the towns. While samples from the bones report an average of diet over the years leading up to an individual's death, carbon and nitrogen isotope signatures taken from the teeth may have a biographical element—capturing those childhood dinners. In this way migrants have been detected—as in the likely presence of Africans in Roman York. While not unexpected, these results show the increasing power of stable isotopes to comment on populations subject to demographic pressures of every kind.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Platinum is one of the most common coatings used to optimize mirror reflectivity in soft X-ray beamlines. Normal operation results in optics contamination by carbon-based molecules present in the residual vacuum of the beamlines. The reflectivity reduction induced by a carbon layer at the mirror surface is a major problem in synchrotron radiation sources. A time-dependent photoelectron spectroscopy study of the chemical reactions which take place at the Pt(111) surface under operating conditions is presented. It is shown that the carbon contamination layer growth can be stopped and reversed by low partial pressures of oxygen for optics operated in intense photon beams at liquidnitrogen temperature. For mirrors operated at room temperature the carbon contamination observed for equivalent partial pressures of CO is reduced and the effects of oxygen are observed on a long time scale.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The United Nation Intergovernmental Panel on Climate Change (IPCC) makes it clear that climate change is due to human activities and it recognises buildings as a distinct sector among the seven analysed in its 2007 Fourth Assessment Report. Global concerns have escalated regarding carbon emissions and sustainability in the built environment. The built environment is a human-made setting to accommodate human activities, including building and transport, which covers an interdisciplinary field addressing design, construction, operation and management. Specifically, Sustainable Buildings are expected to achieve high performance throughout the life-cycle of siting, design, construction, operation, maintenance and demolition, in the following areas: • energy and resource efficiency; • cost effectiveness; • minimisation of emissions that negatively impact global warming, indoor air quality and acid rain; • minimisation of waste discharges; and • maximisation of fulfilling the requirements of occupants’ health and wellbeing. Professionals in the built environment sector, for example, urban planners, architects, building scientists, engineers, facilities managers, performance assessors and policy makers, will play a significant role in delivering a sustainable built environment. Delivering a sustainable built environment needs an integrated approach and so it is essential for built environment professionals to have interdisciplinary knowledge in building design and management . Building and urban designers need to have a good understanding of the planning, design and management of the buildings in terms of low carbon and energy efficiency. There are a limited number of traditional engineers who know how to design environmental systems (services engineer) in great detail. Yet there is a very large market for technologists with multi-disciplinary skills who are able to identify the need for, envision and manage the deployment of a wide range of sustainable technologies, both passive (architectural) and active (engineering system),, and select the appropriate approach. Employers seek applicants with skills in analysis, decision-making/assessment, computer simulation and project implementation. An integrated approach is expected in practice, which encourages built environment professionals to think ‘out of the box’ and learn to analyse real problems using the most relevant approach, irrespective of discipline. The Design and Management of Sustainable Built Environment book aims to produce readers able to apply fundamental scientific research to solve real-world problems in the general area of sustainability in the built environment. The book contains twenty chapters covering climate change and sustainability, urban design and assessment (planning, travel systems, urban environment), urban management (drainage and waste), buildings (indoor environment, architectural design and renewable energy), simulation techniques (energy and airflow), management (end-user behaviour, facilities and information), assessment (materials and tools), procurement, and cases studies ( BRE Science Park). Chapters one and two present general global issues of climate change and sustainability in the built environment. Chapter one illustrates that applying the concepts of sustainability to the urban environment (buildings, infrastructure, transport) raises some key issues for tackling climate change, resource depletion and energy supply. Buildings, and the way we operate them, play a vital role in tackling global greenhouse gas emissions. Holistic thinking and an integrated approach in delivering a sustainable built environment is highlighted. Chapter two demonstrates the important role that buildings (their services and appliances) and building energy policies play in this area. Substantial investment is required to implement such policies, much of which will earn a good return. Chapters three and four discuss urban planning and transport. Chapter three stresses the importance of using modelling techniques at the early stage for strategic master-planning of a new development and a retrofit programme. A general framework for sustainable urban-scale master planning is introduced. This chapter also addressed the needs for the development of a more holistic and pragmatic view of how the built environment performs, , in order to produce tools to help design for a higher level of sustainability and, in particular, how people plan, design and use it. Chapter four discusses microcirculation, which is an emerging and challenging area which relates to changing travel behaviour in the quest for urban sustainability. The chapter outlines the main drivers for travel behaviour and choices, the workings of the transport system and its interaction with urban land use. It also covers the new approach to managing urban traffic to maximise economic, social and environmental benefits. Chapters five and six present topics related to urban microclimates including thermal and acoustic issues. Chapter five discusses urban microclimates and urban heat island, as well as the interrelationship of urban design (urban forms and textures) with energy consumption and urban thermal comfort. It introduces models that can be used to analyse microclimates for a careful and considered approach for planning sustainable cities. Chapter six discusses urban acoustics, focusing on urban noise evaluation and mitigation. Various prediction and simulation methods for sound propagation in micro-scale urban areas, as well as techniques for large scale urban noise-mapping, are presented. Chapters seven and eight discuss urban drainage and waste management. The growing demand for housing and commercial developments in the 21st century, as well as the environmental pressure caused by climate change, has increased the focus on sustainable urban drainage systems (SUDS). Chapter seven discusses the SUDS concept which is an integrated approach to surface water management. It takes into consideration quality, quantity and amenity aspects to provide a more pleasant habitat for people as well as increasing the biodiversity value of the local environment. Chapter eight discusses the main issues in urban waste management. It points out that population increases, land use pressures, technical and socio-economic influences have become inextricably interwoven and how ensuring a safe means of dealing with humanity’s waste becomes more challenging. Sustainable building design needs to consider healthy indoor environments, minimising energy for heating, cooling and lighting, and maximising the utilisation of renewable energy. Chapter nine considers how people respond to the physical environment and how that is used in the design of indoor environments. It considers environmental components such as thermal, acoustic, visual, air quality and vibration and their interaction and integration. Chapter ten introduces the concept of passive building design and its relevant strategies, including passive solar heating, shading, natural ventilation, daylighting and thermal mass, in order to minimise heating and cooling load as well as energy consumption for artificial lighting. Chapter eleven discusses the growing importance of integrating Renewable Energy Technologies (RETs) into buildings, the range of technologies currently available and what to consider during technology selection processes in order to minimise carbon emissions from burning fossil fuels. The chapter draws to a close by highlighting the issues concerning system design and the need for careful integration and management of RETs once installed; and for home owners and operators to understand the characteristics of the technology in their building. Computer simulation tools play a significant role in sustainable building design because, as the modern built environment design (building and systems) becomes more complex, it requires tools to assist in the design process. Chapter twelve gives an overview of the primary benefits and users of simulation programs, the role of simulation in the construction process and examines the validity and interpretation of simulation results. Chapter thirteen particularly focuses on the Computational Fluid Dynamics (CFD) simulation method used for optimisation and performance assessment of technologies and solutions for sustainable building design and its application through a series of cases studies. People and building performance are intimately linked. A better understanding of occupants’ interaction with the indoor environment is essential to building energy and facilities management. Chapter fourteen focuses on the issue of occupant behaviour; principally, its impact, and the influence of building performance on them. Chapter fifteen explores the discipline of facilities management and the contribution that this emerging profession makes to securing sustainable building performance. The chapter highlights a much greater diversity of opportunities in sustainable building design that extends well into the operational life. Chapter sixteen reviews the concepts of modelling information flows and the use of Building Information Modelling (BIM), describing these techniques and how these aspects of information management can help drive sustainability. An explanation is offered concerning why information management is the key to ‘life-cycle’ thinking in sustainable building and construction. Measurement of building performance and sustainability is a key issue in delivering a sustainable built environment. Chapter seventeen identifies the means by which construction materials can be evaluated with respect to their sustainability. It identifies the key issues that impact the sustainability of construction materials and the methodologies commonly used to assess them. Chapter eighteen focuses on the topics of green building assessment, green building materials, sustainable construction and operation. Commonly-used assessment tools such as BRE Environmental Assessment Method (BREEAM), Leadership in Energy and Environmental Design ( LEED) and others are introduced. Chapter nineteen discusses sustainable procurement which is one of the areas to have naturally emerged from the overall sustainable development agenda. It aims to ensure that current use of resources does not compromise the ability of future generations to meet their own needs. Chapter twenty is a best-practice exemplar - the BRE Innovation Park which features a number of demonstration buildings that have been built to the UK Government’s Code for Sustainable Homes. It showcases the very latest innovative methods of construction, and cutting edge technology for sustainable buildings. In summary, Design and Management of Sustainable Built Environment book is the result of co-operation and dedication of individual chapter authors. We hope readers benefit from gaining a broad interdisciplinary knowledge of design and management in the built environment in the context of sustainability. We believe that the knowledge and insights of our academics and professional colleagues from different institutions and disciplines illuminate a way of delivering sustainable built environment through holistic integrated design and management approaches. Last, but not least, I would like to take this opportunity to thank all the chapter authors for their contribution. I would like to thank David Lim for his assistance in the editorial work and proofreading.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Observations show that stratospheric water vapor (SWV) concentrations increased by ~30% between 1980 and 2000. SWV has also been projected to increase by up to a factor of two over the 21st century. Trends in SWV impact on stratospheric temperatures, which may lead to changes in the stratospheric circulation. Perturbations in temperature and wind in the stratosphere have been shown to influence the extratropical tropospheric circulation. This study investigates the response to a uniform doubling in SWV from 3 to 6 ppmv in a comprehensive stratosphere-resolving atmospheric-GCM. The increase in SWV causes stratospheric cooling with a maximum amplitude of 5-6 K in the polar lower stratosphere and 2-3 K in the tropical lower stratosphere. The zonal wind on the upper flanks of the subtropical jets is more westerly by up to ~5 m s−1. Changes in resolved wave drag in the stratosphere result in an increase in the strength of tropical upwelling associated with the Brewer-Dobson circulation of ~10% throughout the year. In the troposphere, the increase in SWV causes significant meridional dipole changes in the midlatitude zonal-mean zonal wind of up to 2.8 m s−1 at 850 hPa, which are largest in boreal winter in both hemispheres. This suggests a more poleward storm track under uniformly increased stratospheric water vapor. The circulation changes in both the stratosphere and troposphere are almost entirely due to the increase in SWV at pressures greater than 50 hPa. The results show that long-term trends in SWV may impact on stratospheric temperatures and wind, the strength of the Brewer-Dobson circulation and extratropical surface climate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Following two decades of policy change, in 2011 the European Commission tabled proposals for a new ‘reform’ of the CAP. A major component of the reform would be a revamping of the existing system of direct payments to farmers. For example, 30% of the spend would be dependent on farmers respecting new greening criteria; and payments would be restricted to active farmers and subject to a payment cap. These proposals will be debated by the Council of Ministers and the European Parliament throughout 2012, and possibly 2013, before final decisions are reached. What aspects, if any, of the proposals will prove acceptable is yet to be discerned. Although tabled as part of a financial package, the proposals do not appear to be driven by financial exigency: indeed they seek to maintain the expenditure status quo. Nor do they appear to be driven by international pressures: if anything, they backtrack on previous attempts to bring the CAP into conformity with a post-Doha WTO Agreement on Agriculture. Instead they seek to establish a new partnership between society and ‘farmers, who keep rural areas alive, who are in contact with the ecosystems and who produce the food we eat’ (Cioloș 2011), in an attempt to justify continuing support.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This research explores the relationship between inheritance, access to resources and the intergenerational transmission of poverty among the Serer ethnic group in rural and urban environments in Senegal. In many Sub-Saharan African countries, customary law excludes women from owning and inheriting assets, such as land and property. Yet, assets controlled by women often result in increased investments in the next generation's health, nutrition and schooling and reduce the intergenerational transmission of poverty. Qualitative research with 60 participants in Senegal reveals the important role that land, housing and financial assets may play in building resilience to household shocks and interrupting the intergenerational transmission of poverty. However, the protection afforded by these assets was often dependent on other factors, including human, social and environmental capital. The death of a spouse or parent had major emotional and material impacts on many Serer families. The inheritance and control of assets and resources was strongly differentiated among family members along lines of gender, age and generation. Younger widows and their children were particularly vulnerable to chronic poverty. Although inheritance disputes were rare, the research suggests they are more likely between co-wives in polygamous unions and their children, particularly in urban areas. In addition to experiencing economic and health-related shocks, many interviewees were exposed to a range of climate-related risks and environmental pressures which increased their vulnerability. Family members coped with these shocks and risks by diversifying livelihoods, migrating to urban areas and other regions for work, participating in women's co-operatives and associations and developing supportive social networks with extended family and community members. Policies and practices that may help to alleviate poverty, safeguard women's and young people's inheritance and build resilience to financial, health-related and environmental shocks and risks include: - Social protection measures targeted towards poor widows and orphaned children, such as social and cash transfers to pay for basic needs including food, healthcare and children's schooling. - Micro-finance initiatives and credit and savings schemes, alongside training and capacity-building targeted to women and young people to develop income-generation activities and skills. - Free legal advice, support and advocacy for women and young people to pursue inheritance claims through the legal system. - Raising awareness about women's and children's legal rights and working with government and community and religious leaders to tackle discriminatory inheritance practices and contradictions caused by legal pluralism. - Increasing women's control of land and access to inputs, enhancing their business, organisational, and leadership skills and promoting civic participation in local, regional and national decision-making processes. - Improving access to basic services in rural areas, particularly healthcare, building the quality of education and promoting girls' access to education - Enhancing agricultural production and providing more employment opportunities, apprenticeships and vocational training for young people, particularly in rural areas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An isolate of L. monocytogenes Scott A that is tolerant to high hydrostatic pressure (HHP), named AK01, was isolated upon a single pressurization treatment of 400 MPa for 20 min and was further characterized. The survival of exponential- and stationary-phase cells of AK01 in ACES [N-(2-acetamido)-2-aminoethanesulfonic acid] buffer was at least 2 log units higher than that of the wild type over a broad range of pressures (150 to 500 MPa), while both strains showed higher HHP tolerance (piezotolerance) in the stationary than in the exponential phase of growth. In semiskim milk, exponential-phase cells of both strains showed lower reductions upon pressurization than in buffer, but again, AK01 was more piezotolerant than the wild type. The piezotolerance of AK01 was retained for at least 40 generations in rich medium, suggesting a stable phenotype. Interestingly, cells of AK01 lacked flagella, were elongated, and showed slightly lower maximum specific growth rates than the wild type at 8, 22, and 30°C. Moreover, the piezotolerant strain AK01 showed increased resistance to heat, acid, and H2O2 compared with the wild type. The difference in HHP tolerance between the piezotolerant strain and the wild-type strain could not be attributed to differences in membrane fluidity, since strain AK01 and the wild type had identical in situ lipid melting curves as determined by Fourier transform infrared spectroscopy. The demonstrated occurrence of a piezotolerant isolate of L. monocytogenes underscores the need to further investigate the mechanisms underlying HHP resistance of food-borne microorganisms, which in turn will contribute to the appropriate design of safe, accurate, and feasible HHP treatments.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The growth of Web 2.0 generation will have influence on developing strong relationships with customers. Even though Web 2.0 technologies and applications have gained significant attention recently by academics and practitioners, research into its potential integration with CRM system remains a poorly investigated subject. This paper aims to investigate the adoption intention of social CRM system, focusing on Saudi banks. A conceptual model was proposed based on technology organisation and environment (TOE) framework. A qualitative approach was applied to validate the research model. The finding suggests that technology infrastructure, and competitive pressures tend to be the most influential drivers to adopt social CRM. In contrast, the limited number of IT experts, security concerns, and organisational structure were found to negatively affect social CRM adoption intention.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This research aims to extend our understanding of the duality between global integration and local responsiveness in multinational corporations (MNCs) by exploring the perceptions of corporate HR actors regarding the intra-organisational factors that alter the balance between these pressures. It examines the perceptions and actions of key actors in the context of two Korean MNCs. The study shows the importance attributed to a range of socio-procedural factors by corporate actors and which, therefore, inform the practical management of the dual forces, notably: HR expertise, social ties, trustworthy relationships and co-involvement in decision processes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Nationalism and multiculturalism are often perceived as polar opposites with the former viewed as the disease and the latter the cure. Contrary to this view, this article argues that a strong national identity, albeit of a particular kind, is prerequisite to a stable and functioning multicultural society. The article seeks to identify both the causes and the implications of the absence of an overarching, civic national identity in Britain, further to the goal of seeking a meaningful solution. It is our contention that the problem lies in the difficulty involved in reconciling current pressures on British identity with a coherent narrative of British history, especially its imperial past.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Time-resolved studies of chlorosilylene, ClSiH, generated by the 193 nm laser flash photolysis of 1-chloro-1- silacyclopent-3-ene, have been carried out to obtain rate constants for its bimolecular reaction with trimethylsilane-1-d, Me3SiD, in the gas phase. The reaction was studied at total pressures up to 100 Torr (with and without added SF6) over the temperature range of 295−407 K. The rate constants were found to be pressure independent and gave the following Arrhenius equation: log[(k/(cm3 molecule−1 s−1)] = (−13.22 ± 0.15) + [(13.20 ± 1.00) kJ mol−1]/(RT ln 10). When compared with previously published kinetic data for the reaction of ClSiH with Me3SiH, kinetic isotope effects, kD/kH, in the range from 7.4 (297 K) to 6.4 (407 K) were obtained. These far exceed values of 0.4−0.5 estimated for a single-step insertion process. Quantum chemical calculations (G3MP2B3 level) confirm not only the involvement of an intermediate complex, but also the existence of a low-energy internal isomerization pathway which can scramble the D and H atom labels. By means of Rice−Ramsperger−Kassel−Marcus modeling and a necessary (but small) refinement of the energy surface, we have shown that this mechanism can reproduce closely the experimental isotope effects. These findings provide the first experimental evidence for the isomerization pathway and thereby offer the most concrete evidence to date for the existence of intermediate complexes in the insertion reactions of silylenes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Evolutionary processes play a central role in the development, progression and response to treatment of cancers. The current challenge facing researchers is to harness evolutionary theory to further our understanding of the clinical progression of cancers. Central to this endeavour will be the development of experimental systems and approaches by which theories of cancer evolution can be effectively tested. We argue here that the experimental evolution approach – whereby evolution is observed in real time and which has typically employed microorganisms – can be usefully applied to cancer. This approach allows us to disentangle the ecological causes of natural selection, identify the genetic basis of evolutionary changes and determine their repeatability. Cell cultures used in cancer research share many of the desirable traits that make microorganisms ideal for studying evolution. As such, experimental cancer evolution is feasible and likely to give great insight into the selective pressures driving the evolution of clinically destructive cancer traits. We highlight three areas of evolutionary theory with importance to cancer biology that are amenable to experimental evolution: drug resistance, social evolution and resource competition. Understanding the diversity, persistence and evolution of cancers is vital for treatment and drug development, and an experimental evolution approach could provide strategic directions and focus for future research.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

There has been an increased amount of scholarly interest lately in T.S. Eliot's unfinished sequence, Coriolan (1932)—interest drawn from its Shakespearian allusiveness, and from analysis of this writing's particularly rebarbative, jarring poetic. Although, however, the two parts of the sequence published by Eliot are acknowledged as being his nearest approach to poetic commentary upon contemporary political ideas, little criticism exists establishing the hinterland of the political thought, with which Eliot was most familiar, as editor of the Criterion. Coriolan emerges at a time when the lure of fascism pulled hardest at Eliot's sensibility. This article reviews the full political context provided by Eliot's journal, as well as considering the connections between that political engagement and the readings of Shakespeare he was also promulgating through this forum, in order to provide a more complex sense than hitherto of the diverse pressures underlying the unsettled nature of the existing Coriolan poems.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Terminal: A Miracle Play with Popular Music from the End of the World is a film and live performance project exploring the politics of post-apocalyptic fiction. A theatrical staging of a morality play for end times and future folk music, it recasts eschatology, as a foundational myth for a future society. Post-apocalyptic writing and cinema are grounded in an ethos of survivalism. Invoking Rousseau’s state of nature, or time before government, these fictions propose violent scenarios in which nuclear holocaust, environmental catastrophe and other disasters generate an individualistic politics of pure pragmatism, negating the possibility of democratic deliberation. Terminal narrates this familiar scenario, but at the same time questions its validity. The film, shot on black and white VHS at Kurt Schwitters’ Merzbarn in Cumbria, dramatises a series of conversations between future-historical archetypes about the needs and pressures of the situation in which they find themselves at the end of the world. The performers then gather to play worshipful songs about acid rain, radiation sickness and eating the dog, using a mix of conventional, obscure and makeshift instruments In the tradition of books such as Russell Hoban’s Riddley Walker and Arthur M. Miller Jr.’s A Canticle for Liebowitz, Terminal imagines artistic expression and new folk traditions for a world to come after the apocalypse. If, as Slavoj Žižek would have it, it is easier to imagine the end of the world than to think of the end of capitalism, the project juxtaposes these two endpoints to test out how alternative scenarios might emerge from the collaborative practice of making theatre and music against a setting of social collapse.