1,907 research outputs found

    Electric Momentum: Dynamics of Transportation Electrification and Stories from the Road

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    The climate is undeniably changing. The Intergovernmental Panel on Climate Change (IPCC) published yet another report this year outlining how extreme weather, brought on by our use of Earth\u27s resources, causes loss of nature and human life around the world. The summer of 2023 broke records for high ocean temperatures and melting polar ice, and abnormally potent floods and fires touched all corners of the Earth. Industrial production of goods, and the personal choices that purchase them, are responsible for massive amounts of greenhouse gases (GHG), including carbon dioxide and methane. GHG emissions thicken the Earth\u27s atmosphere and continue the destabilization of the climate. It\u27s an all-encompassing phenomenon that asks us to reevaluate our relationship with the world: how we extract, consume, and dispose of renewable and non-renewable resources. The United States ranks second in the world for GHG emissions. Transportation is the most significant GHG-emitting sector of the US economy. Passenger vehicles contribute more than half of all transportation emissions. Electric vehicles may be one useful solution to reducing GHG emissions in this country. Rural schools and households have a unique opportunity to benefit from transportation electrification, if government subsidies and public charging infrastructure is in place. This portfolio of journalistic work explores the dynamics of emerging EV technology and to what extent the efficiency and reliability of these vehicles may reduce our climate impacts

    Meat for Missoula: Educating Our Youth on Sustainable Meat Production Practices

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    In autumn 2016, a controversy arose when a student group, Advocates for Animals, took up a campaign against three meat pigs at the PEAS Farm due to strong views about animal consumption. Pigs serve as a central piece of food source education to hundreds of Missoula children who visit the farm every year. Unfortunately, the controversy overshadowed the educational purpose of exposing children to sustainable meat production practices. Moreover, access to the PEAS Farm and good food education is not available to all local children. I wondered whether education was accessible elsewhere. Unfortunately, child-appropriate, culturally relevant food literature is scarce. In my research, I read and critiqued dozens of children’s books on food and farming. However, much of the literature is outdated, inaccurate, or dull. In response, I have written and illustrated a children’s book that provides accurate and relevant information with engaging illustrations. This book could reach an audience that cannot visit the PEAS Farm or access other sustainable food education resources. Offering this kind of information to children allows for important discussion of where food comes from and what kind of food we want in our community

    Experimental Analysis of Heat Transfer in Passive Latent Heat Thermal Energy Storage Systems for CSP Plants

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    Abstract Thermal energy storage is a key factor for efficiency, dispatchability and economic sustainability of concentrated solar plants. The latent heat storage systems could ensure a significant reduction in construction costs and environmental impact, because of its high storage energy density. In LHTES, the heat transfer between the heat transfer fluid and the storage system is strongly limited by the reduced thermal conductivity of the storage media. For operating temperatures between 200 and 600 °C, the most used storage media are salts. In order to evaluate solutions which promote the thermal conductivity, by increasing the exchange surface and/or the addition of nanoparticles to the storage media, Enea set up a small facility to test some storage concepts. In this facility, a diathermic oil flows through three elementary "shell-and-tube" storage systems, connected in series, reaching a maximum temperature of about 280 °C. The elementary storage systems are filled with a mixture of sodium and potassium nitrates salts, which melt at about 225 °C. Moreover a small percentage of alumina and silica nanoparticles were added to this mixture. The results of the experiments show an increase of the thermal diffusivity of the medium not only for the presence of fins on the heat transfer tubes but also because of convective flows within the melted fraction were established. These phenomena strongly reduce the charging times of the system (by about 30%). Instead, the presence of nanoparticles increases the thermal capacity and the thermal conductivity of the storage system but seems not to have a relevant effect on the thermal diffusivity of the mixture. This behavior depends on the type of used nanoparticles, which can significantly change over time some characteristics of the storage medium, in which they are dispersed, leaving other characteristics unchanged, according to mechanisms which are still to be well understood

    On the Complexity of Case-Based Planning

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    We analyze the computational complexity of problems related to case-based planning: planning when a plan for a similar instance is known, and planning from a library of plans. We prove that planning from a single case has the same complexity than generative planning (i.e., planning "from scratch"); using an extended definition of cases, complexity is reduced if the domain stored in the case is similar to the one to search plans for. Planning from a library of cases is shown to have the same complexity. In both cases, the complexity of planning remains, in the worst case, PSPACE-complete

    Pseudozyma aphidis bloodstream infection in a patient with aggressive lymphoma and a history of intravenous drug use: Case report and review of the literature

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    Pseudozyma aphidis is an environmental fungus which causes opportunistic infections in immunocompromised patients. Here we report the case of a 54-year-old, intravenous drug user woman, newly diagnosed to have an aggressive lymphoma, who developed a bloodstream infection caused by P. aphidis treated successfully with amphotericin-B therapy. The precise identification was assessed by sequencing. We propose to consider intravenous drug use as a risk factor for invasive infections due to this environmental yeast

    A discussion of possible approaches to the integration of thermochemical storage systems in concentrating solar power plants

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    One of the most interesting perspectives for the development of concentrated solar power (CSP) is the storage of solar energy on a seasonal basis, intending to exploit the summer solar radiation in excess and use it in the winter months, thus stabilizing the yearly production and increasing the capacity factor of the plant. By using materials subject to reversible chemical reactions, and thus storing the thermal energy in the form of chemical energy, thermochemical storage systems can potentially serve to this purpose. The present work focuses on the identification of possible integration solutions between CSP plants and thermochemical systems for long-term energy storage, particularly for high-temperature systems such as central receiver plants. The analysis is restricted to storage systems potentially compatible with temperatures ranging from 700 to 1000 ◩C and using gases as heat transfer fluids. On the basis of the solar plant specifications, suitable reactive systems are identified and the process interfaces for the integration of solar plant/storage system/power block are discussed. The main operating conditions of the storage unit are defined for each considered case through process simulation

    Compilability of Abduction

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    Abduction is one of the most important forms of reasoning; it has been successfully applied to several practical problems such as diagnosis. In this paper we investigate whether the computational complexity of abduction can be reduced by an appropriate use of preprocessing. This is motivated by the fact that part of the data of the problem (namely, the set of all possible assumptions and the theory relating assumptions and manifestations) are often known before the rest of the problem. In this paper, we show some complexity results about abduction when compilation is allowed

    Software tools for project management: focus on collaborative management

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    Today, projects involve members from different geographical areas more than any other time in history. Thus, adequate Collaborative Project Management Software (CollabPMS) solutions are needed to enable individuals and organizations to manage, communicate and work together across time and space barriers. This article describes a set of managerial and collaborative functionalities that a CollabPMS should provide to support the complexities of a distributed project effectively. Out of hundreds software packages available in the market, four were selected, ProjectLibre, Redmine, Microsoft Project 2013 and Clarizen, to assess if they have the described functionalities. Clarizen can be considered the best software for managing distributed projects, because it provides, by default, all the managerial functions and the collaborative features that support the coordinated collaboration level. ProjectLibre was the software that less stood out in this evaluation, although it provides the majority of the outlined managerial functionalities it doesn't support any level of collaboration.info:eu-repo/semantics/publishedVersio

    Influence of oxidant agent on syngas composition: gasification of hazelnut shells through an updraft reactor

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    Thermophysical properties of engineering fluids have proven in the past to be essential for the design of physical and chemical processing and reaction equipment in the chemical, metallurgical, and allied industries, as they influence directly the design parameters and performance of plant units in the of, for example, heat exchangers, distillation columns, phase separation, and reactors. In the energy field, the search for the optimization of existing and alternative fuels, either using neutral or ionic fluids, is an actual research and application topic, both for new applications and the sustainable development of old technologies. One of the most important drawbacks in the industrial use of thermophysical property data is the common discrepancies in available data, measured with different methods, different samples, and questionable quality assessment. Measuring accurately the thermal conductivity of fluids has been a very successful task since the late 1970s due to the efforts of several schools in Europe, Japan, and the United States. However, the application of the most accurate techniques to several systems with technological importance, like ionic liquids, nanofluids, and molten salts, has not been made in the last ten years in a correct fashion, generating highly inaccurate data, which do not reflect the real physical situation. It is the purpose of this paper to review critically the best available techniques for the measurement of thermal conductivity of fluids, with special emphasis on transient methods and their application to ionic liquids, nanofluids, and molten salts

    Pressure-dependent EPANET extension

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    In water distribution systems (WDSs), the available flow at a demand node is dependent on the pressure at that node. When a network is lacking in pressure, not all consumer demands will be met in full. In this context, the assumption that all demands are fully satisfied regardless of the pressure in the system becomes unreasonable and represents the main limitation of the conventional demand driven analysis (DDA) approach to WDS modelling. A realistic depiction of the network performance can only be attained by considering demands to be pressure dependent. This paper presents an extension of the renowned DDA based hydraulic simulator EPANET 2 to incorporate pressure-dependent demands. This extension is termed “EPANET-PDX” (pressure-dependent extension) herein. The utilization of a continuous nodal pressure-flow function coupled with a line search and backtracking procedure greatly enhance the algorithm’s convergence rate and robustness. Simulations of real life networks consisting of multiple sources, pipes, valves and pumps were successfully executed and results are presented herein. Excellent modelling performance was achieved for analysing both normal and pressure deficient conditions of the WDSs. Detailed computational efficiency results of EPANET-PDX with reference to EPANET 2 are included as well
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