328,325 research outputs found

    A Hidden Resource: Household-led Rural Water Supply in Ethiopia

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    Self supply as a strategy for WASH is defined as "improvement to water supplies delivered largely or wholly through user investment usually at household level." The two research studies reported on in this paper examined self supply in rural Ethiopia, gaining insights on the performance of existing family wells, factors that affect the decision of families to build their own wells and the way they use them, and elements of the enabling environment that can be targeted to promote self supply

    Mathematical modelling of operation modes and performance evaluation of an innovative small-scale concentrated solar organic Rankine cycle plant

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    In this paper an innovative small-scale concentrated solar 2 kWe organic Rankine cycle plant coupled with a phase change material storage tank equipped with reversible heat pipes is investigated using a simulation analysis. The plant, intended for residential applications, is going to be built and tested under the European funded H2020 Innova MicroSolar project executed by the consortium of several Universities and industrial organizations, led by Northumbria University. The authors of this work used the design of the integrated system, developed by the consortium, to preliminary estimate the overall performance of the system in order to provide useful information for its forthcoming real operation. In particular, according to the varying ambient conditions, the influence of different operation modes of the prototype plant are evaluated. The dynamic simulation analysis has shown an interesting performance of the system in terms of annual operating hours, power production and conversion efficiencies. More precisely, the organic Rankine cycle unit is able to operate for more than 3100 h/year, achieving the design performance when solar power is sufficiently high, producing about 5100 kWhe/year. For the considered operating set-point temperatures of the thermal energy storage, the plant is able to reach high conversion efficiency also when the organic Rankine cycle unit is supplied by discharging the energy stored in the storage tank, for about 800 h/year. Hence, the work has provided some useful insights into the best working conditions of such micro combined heat and power system to be integrated in residential buildings. Moreover, the analysis could serve as a general guide for the design and optimization of the mutual interactions of the different subsystems in small-scale concentrated solar organic Rankine cycle plants

    Scenarios for the development of smart grids in the UK: literature review

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    Smart grids are expected to play a central role in any transition to a low-carbon energy future, and much research is currently underway on practically every area of smart grids. However, it is evident that even basic aspects such as theoretical and operational definitions, are yet to be agreed upon and be clearly defined. Some aspects (efficient management of supply, including intermittent supply, two-way communication between the producer and user of electricity, use of IT technology to respond to and manage demand, and ensuring safe and secure electricity distribution) are more commonly accepted than others (such as smart meters) in defining what comprises a smart grid. It is clear that smart grid developments enjoy political and financial support both at UK and EU levels, and from the majority of related industries. The reasons for this vary and include the hope that smart grids will facilitate the achievement of carbon reduction targets, create new employment opportunities, and reduce costs relevant to energy generation (fewer power stations) and distribution (fewer losses and better stability). However, smart grid development depends on additional factors, beyond the energy industry. These relate to issues of public acceptability of relevant technologies and associated risks (e.g. data safety, privacy, cyber security), pricing, competition, and regulation; implying the involvement of a wide range of players such as the industry, regulators and consumers. The above constitute a complex set of variables and actors, and interactions between them. In order to best explore ways of possible deployment of smart grids, the use of scenarios is most adequate, as they can incorporate several parameters and variables into a coherent storyline. Scenarios have been previously used in the context of smart grids, but have traditionally focused on factors such as economic growth or policy evolution. Important additional socio-technical aspects of smart grids emerge from the literature review in this report and therefore need to be incorporated in our scenarios. These can be grouped into four (interlinked) main categories: supply side aspects, demand side aspects, policy and regulation, and technical aspects.

    Cloudbus Toolkit for Market-Oriented Cloud Computing

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    This keynote paper: (1) presents the 21st century vision of computing and identifies various IT paradigms promising to deliver computing as a utility; (2) defines the architecture for creating market-oriented Clouds and computing atmosphere by leveraging technologies such as virtual machines; (3) provides thoughts on market-based resource management strategies that encompass both customer-driven service management and computational risk management to sustain SLA-oriented resource allocation; (4) presents the work carried out as part of our new Cloud Computing initiative, called Cloudbus: (i) Aneka, a Platform as a Service software system containing SDK (Software Development Kit) for construction of Cloud applications and deployment on private or public Clouds, in addition to supporting market-oriented resource management; (ii) internetworking of Clouds for dynamic creation of federated computing environments for scaling of elastic applications; (iii) creation of 3rd party Cloud brokering services for building content delivery networks and e-Science applications and their deployment on capabilities of IaaS providers such as Amazon along with Grid mashups; (iv) CloudSim supporting modelling and simulation of Clouds for performance studies; (v) Energy Efficient Resource Allocation Mechanisms and Techniques for creation and management of Green Clouds; and (vi) pathways for future research.Comment: 21 pages, 6 figures, 2 tables, Conference pape

    Storage Solutions for Big Data Systems: A Qualitative Study and Comparison

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    Big data systems development is full of challenges in view of the variety of application areas and domains that this technology promises to serve. Typically, fundamental design decisions involved in big data systems design include choosing appropriate storage and computing infrastructures. In this age of heterogeneous systems that integrate different technologies for optimized solution to a specific real world problem, big data system are not an exception to any such rule. As far as the storage aspect of any big data system is concerned, the primary facet in this regard is a storage infrastructure and NoSQL seems to be the right technology that fulfills its requirements. However, every big data application has variable data characteristics and thus, the corresponding data fits into a different data model. This paper presents feature and use case analysis and comparison of the four main data models namely document oriented, key value, graph and wide column. Moreover, a feature analysis of 80 NoSQL solutions has been provided, elaborating on the criteria and points that a developer must consider while making a possible choice. Typically, big data storage needs to communicate with the execution engine and other processing and visualization technologies to create a comprehensive solution. This brings forth second facet of big data storage, big data file formats, into picture. The second half of the research paper compares the advantages, shortcomings and possible use cases of available big data file formats for Hadoop, which is the foundation for most big data computing technologies. Decentralized storage and blockchain are seen as the next generation of big data storage and its challenges and future prospects have also been discussed
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