467 research outputs found

    Transformation of a university building into a zero energy building in Mediterranean climate.

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    In the context of environmental policy, the EU has launched a series of initiatives aimed at increasing the use of energy efficiency, as it has pledged to reduce energy consumption by 20%, compared with projected levels of growth of CO2 emissions into the atmosphere by 2020. In Greece CO2 emission levels in the atmosphere have risen significantly over the past two decades [1]. For the year 2011, CO2 emissions per person in Greece correspond to 7.56 t. According to the data, this increase in emissions is reflected to a 151.2% above from the levels of 1980 and a 756% increase from 1960 levels. The building sector consumes the largest amount of energy in Greece, therefore constitutes the most important source of CO2 emissions. The energy upgrade of the building sector produces multiple benefits such as reduced energy consumption, which is consistent with the reduction of air pollution. Additionally, there is a significant improvement at the interior comfort conditions of the building, which promotes productivity and occupant health. Moreover, because of the large number of educational buildings in the country, the energy consumption of them present a significant amount of the country's total energy consumption and simultaneously has the effect of increasing the costs paid by the state budget for the operation and maintenance of public buildings. The investigation of alternative methods to reduce energy consumption in educational buildings is an important approach for sustainability and economic development of the country over time. The purpose of this paper is to study and evaluate the energy saving methods of a university building in Mediterranean climate with significant energy consumption. Additionally, through Building Information Modeling (BIM) and Computational Fluid Dynamics (CFD) software, studies considering the contribution of passive heating and cooling techniques were conducted, in order to minimize energy consumption in pursuit of desirable interior thermal comfort conditions.N/

    ENVIRONMENTAL – HYDROGEOLOGICAL INVESTIGATIONS ON THE CLAY DEPOSITS IN THE BROAD AREA OF MESOLOGGI – AITOLIKO LAGOONS

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    A hydrogeological study took place in the broader area of Mesologgi – Aitoliko lagoons (West Greece) aiming at the investigation of a) the hydrogeological conditions of the area as well as the surface and groundwater influences on the quality of the clay deposits found in the lagoons and b) the properties of the clay in order to be identified as “therapeutic peloids”. Due to their location, the clay deposits could be influenced and possibly polluted from the surface waters. The aquifer of the unconsolidated formations presents low hydraulic conductivity, while the carbonate aquifer is bounded from the foregoing aquifer and therefore the possibility of clay pollution from the groundwater is very limited. pH of the sediments showing neutral and alkaline values, limits the mobility of some pollutants. Seawater affects some of the clay samples, which present high electrical conductivity. Iron and manganese show also high concentrations, while some of trace elements such as Cd, Hg, Hf, Be, Ag present concentrations under the detection limit. Most of the organic material of the clay consists of humus and therefore they could be suitable for fangotherapy

    The challenge of changing deeply-held student beliefs about the relativity of simultaneity

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    Previous research indicates that after standard instruction students at all academic levels often construct a conceptual framework in which the ideas of absolute simultaneity and the relativity of simultaneity co-exist. This article describes the development and assessment of instructional materials intended to improve student understanding of the concept of time in special relativity, the relativity of simultaneity, and the role of observers in inertial reference frames. Results from pretests and post-tests are presented to demonstrate the effect of the curriculum in helping students deepen their understanding of these topics. Excerpts from taped interviews and classroom interactions help illustrate the intense cognitive conflict that students encounter as they are led to confront the incompatibility of their deeply-held beliefs about simultaneity with the results of special relativity.Comment: 17 pages, 6 figures, 2 tables, 27 references; Accepted for publication in Physics Education Research Section, American Journal of Physics (2001

    COMBINING ADVANCED DATA ANALYSIS METHODS FOR THE CONSTITUTION OF AN INTEGRATED GAS TURBINE CONDITION MONITORING AND DIAGNOSTIC SYSTEM

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    ABSTRACT This paper presents principles for the constitution of gas turbine monitoring and diagnostic systems which: a. are integrated, namely manage all the tasks essential for achieving a diagnosis (measurement, analysis, interpretation, historical data management etc.) b. employ different kind of processing methods in order to cover an extensive range of engine conditions, including direct data evaluation and data consistency checks, thermodynamic analysis, vibration analysis. The requirements to be fulfilled by an industrial gas turbine monitoring system are briefly reviewed and ways to achieve them are discussed, indicating how they can be materialized by implementation of specific techniques. Techniques previously derived by the group of the authors are implemented, and the merits they offer when used in combination are discussed. Features of a system, materialized according to the principles discussed, into an operating industrial gas turbine is presented. On-line application of advanced analysis techniques, such as adaptive performance modeling is discussed, on the basis of observations of the collected data. Data collected from an engine operating in the field are presented to substantiate the matters discussed, and cases of successful fault identification are shown

    ‘The International Teacher Leadership project,’ a case of international action research.

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    Copyright CARNThe paper arises from the International Teacher Leadership project, a research and development project involving researchers and practitioners in 14 European countries. The paper provides a conceptual exploration of the idea of teacher leadership and its role in educational reform, central to which is the idea that teachers, regardless of their level of power and organisational position, can engage in the leadership of enquiry-based development activity aimed at influencing their colleagues and embedding improved practices in their schools. The paper provides an outline of the project’s methodology which builds on that used in the Carpe Vitam Leadership for Learning project (Frost, 2008a). It is a form of collaborative action research which is highly developmental and discursive. It seeks to identify principles, strategies and tools that can be applied in a range of cultural settings. The paper includes a thematic analysis of the cultural contexts and policy environments of the participating countries in order to identify the obstacles to teacher leadership and to inform the nature of the support strategies employed

    Towards Understanding the Roaming Mechanism in H + MgH → Mg + HH Reaction

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    The roaming mechanism in the reaction H + MgH →Mg + HH is investigated by classical and quantum dynamics employing an accurate ab initio three-dimensional ground electronic state potential energy surface. The reaction dynamics are explored by running trajectories initialized on a four-dimensional dividing surface anchored on three-dimensional normally hyperbolic invariant manifold associated with a family of unstable orbiting periodic orbits in the entrance channel of the reaction (H + MgH). By locating periodic orbits localized in the HMgH well or involving H orbiting around the MgH diatom, and following their continuation with the total energy, regions in phase space where reactive or nonreactive trajectories may be trapped are found. In this way roaming reaction pathways are deduced in phase space. Patterns similar to periodic orbits projected into configuration space are found for the quantum bound and resonance eigenstates. Roaming is attributed to the capture of the trajectories in the neighborhood of certain periodic orbits. The complex forming trajectories in the HMgH well can either return to the radical channel or “roam” to the MgHH minimum from where the molecule may react
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