68 research outputs found

    Biomass for Energy Country Specific Show Case Studies

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    In many domestic and industrial processes, vast percentages of primary energy are produced by the combustion of fossil fuels. Apart from diminishing the source of fossil fuels and the increasing risk of higher costs and energy security, the impact on the environment is worsening continually. Renewables are becoming very popular, but are, at present, more expensive than fossil fuels, especially photovoltaics and hydropower. Biomass is one of the most established and common sources of fuel known to mankind, and has been in continuous use for domestic heating and cooking over the years, especially in poorer communities. The use of biomass to produce electricity is interesting and is gaining ground. There are several ways to produce electricity from biomass. Steam and gas turbine technology is well established but requires temperatures in excess of 250 °C to work effectively. The organic Rankine cycle (ORC), where low-boiling-point organic solutions can be used to tailor the appropriate solution, is particularly successful for relatively low temperature heat sources, such as waste heat from coal, gas and biomass burners. Other relatively recent technologies have become more visible, such as the Stirling engine and thermo-electric generators are particularly useful for small power production. However, the uptake of renewables in general, and biomass in particular, is still considered somewhat risky due to the lack of best practice examples to demonstrate how efficient the technology is today. Hence, the call for this Special Issue, focusing on country files, so that different nations’ experiences can be shared and best practices can be published, is warranted. This is realistic, as it seems that some nations have different attitudes to biomass, perhaps due to resource availability, or the technology needed to utilize biomass. Therefore, I suggest that we go forward with this theme, and encourage scientists and engineers who are researching in this field to present case studies related to different countries. I certainly have one case study for the UK to present

    Role of the potential landscape on the single-file diffusion through channels.

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    Transport of colloid particles through narrow channels is ubiquitous in cell biology as well as becoming increasingly important for microfluidic applications or targeted drug delivery. Membrane channels in cells are useful models for artificial designs because of their high efficiency, selectivity, and robustness to external fluctuations. Here, we model the passive channels that let cargo simply diffuse through them, affected by a potential profile along the way. Passive transporters achieve high levels of efficiency and specificity from binding interactions with the cargo inside the channel. This however leads to a paradox: why should channels which are so narrow that they are blocked by their cargo evolve to have binding regions for their cargo if that will effectively block them? Using Brownian dynamics simulations, we show that different potentials, notably symmetric, increase the flux through narrow passive channels - and investigate how shape and depth of potentials influence the flux. We find that there exist optimal depths for certain potential shapes and that it is most efficient to apply a small force over an extended region of the channel. On the other hand, having several spatially discrete binding pockets will not alter the flux significantly. We also explore the role of many-particle effects arising from pairwise particle interactions with their neighbours and demonstrate that the relative changes in flux can be accounted for by the kinetics of the absorption reaction at the end of the channel.Simulations were funded by the Cavendish Laboratory teaching committee and per- formed using the Darwin Supercomputer of the Univer- sity of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. us- ing Strategic Research Infrastructure Funding from the Higher Education Funding Council for England.This is the accepted manuscript. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/jcp/141/22/10.1063/1.490317

    Energy Audits: A Workbook for Energy Management in Buildings

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    Energy efficiency is today a crucial topic in the built environment – for both designers and managers of buildings. This increased interest is driven by a combination of new regulations and directives within the EU and worldwide to combat global warming. All buildings now must now acquire and display an EPC (energy performance certificate), a rating similar to the A–G rating given to white goods. But in order to understand how to be more efficient in energy use, you need first to understand the mechanisms of both energy requirements and how energy is used in buildings. Energy Audits: a workbook for energy management in buildings tackles the fundamental principles of thermodynamics through day–to–day engineering concepts and helps students understand why energy losses occur and how they can be reduced. It provides the tools to measure process efficiency and sustainability in power and heating applications, helping engineers to recognize why energy losses occur and how they can be reduced utilizing familiar thermodynamic principles. The author describes the sources of energy available today; explains how energy is used in buildings – and how energy is lost – and how this can be controlled and reduced. Investments in energy efficiency are considered for a number of case studies conducted on real buildings The book explains the theory; illustrates it with case studies and worked examples; and then tests students’ understanding with tutorial problems. This is an invaluable resource for students on engineering and building courses where energy management is now a core topic

    Engineering Thermodynamics

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    Thermodynamics is an essential subject taught to all science and engineering students. If the coverage of this subject is restricted to theoretical analysis, students will resort to memorising the facts in order to pass the examination. Therefore, this book is set out with the aim to present this subject from an angle of demonstration of how these laws are used in practical situation. This book is designed for the virtual reader in mind, it is concise and easy to read, yet it presents all the basic laws of thermodynamics in a simplistic and straightforward manner; plus many worked examples and a good section of unsolved tutorial problems

    Cryogenic engineering

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    Rocket propulsion elements

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