1,721,009 research outputs found
Confronto tra il metodo di Glaser e un modello globale di trasporto di calore e di massa in regime dinamico
No full textTrasporto di calore e di massa nei materiali da costruzione porosi: influenza delle condizioni al contorno sui fenomeni di condensaziobne
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Environmental analysis of an innovative system based on Municipal Solid Waste pyrolysis and combined cycle
No full textThis paper presents the environmental impact analysis of an innovative system based on the pyrolysis of MSW which produces solid (char), liquid (tar) and gas (syngas) fuels used in a combined cycle for electric power generation. The syngas, after filtration and compression, feeds two gas turbines. In turn, the exhaust from the gas turbines, after post-combustion with char and tar, drives a steam turbine power plant. The flue gas, before discharge, is processed in a SCR (Selective Catalytic Reduction) unit to reduce CO, VOC and NOx content and filtered to remove particulate matter.
This innovative approach to energy recovery from MSW reconciles high energy efficiency with low polluting emissions. The environmental analysis includes the study of the polluting emissions and the simulation of their concentration in the area surrounding the plant to evaluate the potential environmental benefits compared to a traditional, oil or coal burning, power plan
Dynamic modelisation of interaction between wall and indoor air
No full textThe current methodology used for testing the
thermohygrometric behaviour of building structures is
proposed by the standard UNI EN ISO 13788.
This Standard evaluates the risk of hygrometric damages
due to:
1) critical moisture conditions of the inner surfaces of
the building;
2) interstitial condensation within the structures
The proposed procedures are valid in the case of steady
state and are applied on a monthly basis. However, the
steady state calculation is not completely correct mainly
because the vapour production is not constant neither in
time nor in space. For example, residential buildings are
not occupied during most of the day. Therefore, in the
case of a residential building, there is an intense
generation of moisture mainly during a certain period of
the day. Then, for a better control of the indoor values of
relative humidity (and of partial vapour pressure) inside
a given room, the indoor moisture production should be
not considered constant and it may be appropriate to
assess the importance of the hygroscopic properties the
walls and furniture, able to act as a moisture buffer.
In this paper, using a simplified model taking into
account the interactions between the vapour
concentration of the indoor air and the interior walls and
furniture, the role played by the hygroscopic capacity of
the indoor walls and furniture for the evaluation of
indoor relative humidity is analyzed
Analytical and Experimental Investigations on the Transient Heat Transfer Process in Moist Wood Wool Slabs
No full textHeat and moisture transfer in wood wool slabs (shredded wood with Portland cement binder) has been investigated both experimentally and theoretically. The purpose of this study is the analysis of the process of moisture redistribution taking place inside wood wool slabs conditioned to moisture equilibrium (e.g., in a climatic chamber) and then mounted in a guarded hot plate or heat flux meter apparatus to measure the specimen thermal resistance. A theoretical analysis of the heat and mass transfer process for such a material was performed and then a suitable numerical model was used to predict and analyse the moisture redistribution. The porous media may be modelled as a multiphase system constituted by a solid matrix and a network of interconnected pores, partly filled with liquid water and partly with moist air. Three equations have been derived: conservation of the mass of the dry air, the conservation of the mass of water species (liquid and vapour) and the energy balance. These equations have been supplemented with the thermodynamic relations and the constitutive equations needed for the closure of the model. The experimental work was performed on a slab cut into several slices. During the experimental tests, the temperature and heat flow rate data was collected both during the steady state conditions to get the thermal resistance and during the initial transient period, when the heat flow rate is continuously varying. At the end of the test, the slices were weighed to get information on the moisture redistribution. The moisture data versus heat flow rate and temperature on the two faces of the specimen, and information about the final moisture distribution were compared with those obtained by numerical simulation. Substantial agreement between numerical result and experimental data was found
In situ measurements of thermal resistance of a roof with heat flowmeter method: application and comparison of the approaches proposed by standard ISO 9869 for the analysis of data
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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
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