1,721,004 research outputs found
Preliminary analysis of the influence of environmental boundary conditions on convective heat transfer coefficients
Full text linkConvergence criteria analysis for thermal conductance measurements of building walls: A case study
No full textExperimental Analysis of the Thermal Performance of Wood Fiber Insulating Panels
Full text linkDuring the last decades, attention to energy and environmental problems has significantly grown, along with the development of international and national policies addressing sustainability issues. In the construction sector, one of the most widespread energy efficiency strategies consists of thermal insulation of buildings thanks to external insulating panels. Among these, wood fiber is an insulating material characterized by a natural, eco-sustainable and biodegradable structure, coming from the recycling of waste wood from sawmills. The present study aimed to characterize small test building insulated with wood fiber panels from the thermal point of view, comparing the results with those of an identical, non-insulated reference test building. The experimental campaign highlighted several advantages and an excellent thermal performance provided by the eco-sustainable solution of wood fiber insulating panels: Lower values of the thermal transmittance (-57%), thus ensuring greater stability of the internal air temperature and better values in terms of attenuation (-60% in summer and -74 % in winter) and phase shift (+2 h in summer and +2.28 h in winter) compared to those obtained from the reference building. The material is also equipped with an Environmental Performance Declaration (EPD) that certifies its environmental benefits
From efficient to sustainable and zero energy consumption buildings: Green buildings rating systems
No full textThe first evidence of the need of a sustainability concern dates to the 1970s, when the 1973 and 1979 energy crises showed the impossibility of making human development to rely only on nonrenewable energy resources. Such awareness was at the origin of the most widely accepted definition of sustain- able development, which is traced back to 1987, when the Brundtland Commis- sion, the United Nation’s World Commission on Environment and Development, proposed that “sustainable development is development that meets the needs of the present without compromising the ability of future gen- erations to meet their own needs” [1].
Sustainability is, therefore, a concept that embraces several fields and can be applied to widely different scales. A measure of sustainability is essential to compare different and competing alternatives when a selection of materials, energy resources, and production processes has to be performed [2].
In developed countries, a very large share of energy consumption (~ 40%) and CO2 emissions ( 30%) is due to buildings [3,4]. It is, therefore, quite nat- ural that over the years several green building rating tools have been conceived to assess the degree of sustainability pertaining to a building construction, oper- ation and, eventually, disposal, with the final aim of controlling and reducing their environmental impact. The earliest green building rating tool was estab- lished in the United Kingdom in 1990: the first version of the Building Research Establishment Environmental Assessment Method (BREEAM) for buildings. Soon after, the GBTool was released in 1996 by Natural Resources Canada, while the United State Green Building Council (USGBC) issued the first ver- sion of the Leadership in Energy and Environmental Design (LEED) rating sys- tem in 1998. Historically, the first type of labeling applied to buildings regarded energy efficiency. In Europe, for example, following the request by the Energy Performanceof Buildings Directive(EPBD), issuedbythe European Commission, each member country has to make mandatory the need of an Energy Performance Certificate (EPC) for the existing and new buildings. Energy efficiency in a build- ing is usually one of the most important ingredients [5] in the overall recipe that produces a green building label. However, energy efficiency and sustainability may be conflicting [6,7]. While energy efficiency labeling is mandatory, sustain- ability labeling is still mostly made on a voluntary basis.
This chapter aims at describing the most important and widespread green building rating tools in order to develop a critical analysis, highlighting simi- larities and differences among them, and providing end users with useful guide- lines for applying sustainability procedures.
The chapter structure is as follows. In the following section, the main fea- tures of the green building rating systems (GBRSs) are highlighted. In the sub- sequent section, a detailed description of eight international labeling systems is provided. Then, a comparison and a critical discussion of the similarities and differences among the analyzed rating tools are given. Finally, the conclusions are drawn
On the energy performance of an innovative green roof in the mediterranean climate
No full textGreen roofs have a thermal insulating effect known since ancient times. In the building sector, green roofs represent a sustainable passive solution to obtain energy savings, both during winter and summer. Moreover, they are a natural barrier against noise pollution, reducing sound reflections, and they contribute to clean air and biodiversity in urban areas. In this research, a roof-lawn system was studied through a long experimental campaign. Heat-flow meters, air and surface temperature sensors were used in two buildings characterized by different surrounding conditions, geometries and orientations. In both case studies, the thermal behaviors of the roof-lawn system were compared with the conventional roofs. In addition, a dynamic simulation model was created in order to quantify the effect of this green system on the heating and cooling energy demands. The roof-lawn showed a high thermal inertia, with no overheating during summer, and a high insulating capacity, involving energy savings during winter, and consequently better indoor thermal conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A New Tool for the Retrieval of Effective Permittivity of Ground by Using a Commercial GPR
No full text"We propose a fast and effective method for estimating the dielectric permittivity of pavement materials. The method is based on a transmission-line analytical model of the ground and on the use of a commercial ground penetrating radar (GPR) system. In order to verify its reliability and effectiveness, we apply the method for retrieving material permittivity of an actual airport taxiway pavement. We estimate the permittivity comparing the measured GPR received signal and the analytical one. The correct permittivity values are found by imposing the maximum correlation between the measured GPR signal and the analytical one.
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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