1,720,986 research outputs found
The impact of renewable energy systems on local sustainability
No full textThe purpose of the paper is to discuss and assess the impact of renewable energy, RE, generation on sustainable communities, with a specific focus on employment impact. In recent years, local authorities have been involved in the energy planning process due to the site-specific nature of renewable production and thanks to their nearer connection to citizens. Four small and medium-size sustainable communities belonging to Marche region, in central Italy, have been analysed. The work forecasts the employment generated by the RE capacity defined by two different energy scenarios: 1) the 'business as usual' scenario with a 20% CO2 emission reduction target by 2020, where all the energy policies suggested by Sustainable Energy Action Plans have been considered; 2) the 'potential' scenario with a 50% CO2 emission reduction target by 2050. Results show that the spreading of renewable energy, as expected, can increase local jobs, although the high investments required and problems connected to the impact on the grid have to be considered in the analysis of the global economic effect
Improvement of a multiphase flow model for wellhead chokes under critical and subcritical conditions using field data
No full textThe characterization of the multiphase flow through valves and orifices is a problem yet to be solved in engineering design, and there is a need for a prediction model able to simulate the complexity of this kind of flow in relation to fluid thermodynamic behaviour, and applicable to different incoming stream conditions and compositions. The present paper describes the development of a global model for the calculation of the discharge coefficient of orifices and choke valves operating under two- and three-phase flow as well as critical and subcritical conditions. The model generalizes the hydrovalve model developed by Selmer-Olsen et al. (in: Wilson (ed) Proceedings of 7th international conference on Multiphase Production, BHR Group, pp 441–446, 1995) and the Henry–Fauske (J Heat Transfer 93: 179–187, 1971. https://doi.org/10.1115/1.3449782) non-equilibrium model on the basis of an updated definition of the discharge coefficient. The model has been adapted to real choke valve geometries, by fitting the discharge coefficient and model parameters using field data from three production wells. The model developed is a global quartic function with different constants for the different valve geometries. The new discharge coefficient allows to simulate field data with high accuracy
Evaluation of the environmental benefits of new high value process for the management of the end of life of thin film photovoltaic modules
No full textThis paper presents the preliminary results of an environmental evaluation carried out by the application of Life Cycle Analysis (LCA), to a new method proposed for managing the end of life of thin film photovoltaic panels that is being developed by a company leader in design and installation of photovoltaic solutions. The new method is being developed in an experimental test facility established by the company for implementing a series of mechanical and hydro mechanical treatments to thin film panels at the end of their life before the ultimate material recovery phase. The main innovation of the method consists in the elimination of the thermal treatments and the reduction of chemicals needed for recovering valuable materials, in favor of mechanical processes. The results demonstrate that the mechanical treatments used in the pre-treatment phase of the module has a positive effect in almost all the damage categories defined in the LCA and contribute significantly to the reduction of the global warming and the carbon footprint of the photovoltaic technology
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
Technical and economic analysis of different cogeneration systems for energy production from biomass
No full textThis paper compares the results of a techno-economic performance
analysis of seven plants for energy production from biomass with the
aim of identifying the most effective solution. Small ( ≤ 250 KWe) and micro
( ≤ 100 KWe) size plants were investigated: 50 kWe diesel internal combustion
engine coupled with a gasifier and 35 kWe Stirling engine coupled with a
gasifier with an overall efficiency of 41.1% and 87.5% respectively, two
biomass cogenerators, one of 25 kWe and the other of 100 kWe, 250 kWe Otto
internal combustion engine coupled with a gasifier and 250 kWe diesel internal
combustion engine coupled with a gasifier and 238 kWe biomass ORC plant.
The technical analysis provided calculations for specific biomass consumption,
electricity generation, heat produced and overall system efficiency. The
economic evaluation was carried on through a discounted cash flow analysis.
Data were provided by literature, analysis of case study at Italian and European
level, and directly by the manufacturers of cogeneration systems. The results
showed that a combined heat and power (CHP) generator is the best solution
because it is economically viable with a high NPV and a PBP of five years
and also technically performing with a global efficiency of 78.2% and a low
biomass consumption
Experimental and numerical investigation of natural convection in tilted square cavity filled with air
No full textMULTIPHASE FLOW OF HYDROCARBONS FLUIDS THROUGH ORIFICES: VALIDATION OF OLGA 2000 FLOW MODEL
No full textVariations 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
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