1,721,059 research outputs found
Thermoeconomic analysis of csp air-Steam mixed cycles
No full textThis paper investigates the integration of Concentrating Solar Power technology in air-steam Mixed Cycles for power production. Starting from a state of the art of CSP plants and the undergoing research in hybridization of Gas Turbine plants, the paper investigates alternative plant configurations particularly regarding the integration of CSP technology with mixed cycles, assessed and compared with a through-life thermo-economic analysis. Solar heat collected by on the market CSP mirrors at moderate temperatures (300°C-500°C) can be employed to increase conventional steam-injection gas turbine power plants performances. Solar concentrating collectors for current steam solar power plants can be used for such an application can be simpler and less expensive than collectors supposed to be used for hybrid GT CSP Plants which need high temperature systems (collectors and receivers). The solar hybridization of mixed cycles could be a good opportunity to combine gas turbine technology and CSP systems thus augmenting efficiency and achieving power dispatchability, but avoiding dedicated combustion chambers for hybrid CSP purposes (one of the big technologic problems to combine CSP and Gas Turbine technology). Moreover, the availability of commercial steam injected gas turbines at intermediate power range (10-100MW) allows the realization of such hybrid mixed CSP power plants in their typical size, avoiding the need for very large solar fields and reducing the technological risk as well as the time to market. Focus is on the design of the plant that was made analyzing different factor like solar share factor1, water consumption and reintegration and LCOE. A comparison of this innovative hybrid CSP-STIG plant with traditional STIG, Integrated Solar Combined Cycles (ISCC) and a traditional Combined Cycle was made. The mixed cycles CSP plants are analyzed using the original software WTEMP for the design point analysis, whose library was updated with dedicated modules. The analysis shows that combining CSP technology with existing mixed cycles lets cost-competitive plant configurations with a relatively short time to market
The Effect of Cultural Capital on High School Dropout: An Investigation in the Italian Provinces
No full textThis article studies at a detailed geographical level the relation between cultural capital and high school dropout. Bronfenbrenner's systemic theory and Heckman's perspective on cognitive/non-cognitive skills are considered as theoretical framework. We analyzed data from 103 Italian provinces employing Covariance Structure Analysis and spatial indices of autocorrelation. We found a consistent protective effect of cultural capital on dropout, independently of economic performance, in Central and Southern provinces, but not in Northern provinces. Spatial analyses showed very heterogeneous patterns of autocorrelation for dropout (especially across Southern provinces) even between neighboring areas, in spite of a more compact clustering when considering cultural and economic indicators. These results indicate that living in an environment with animated cultural life might enhance students' non-cognitive skills, thus fostering their involvement in formative activities and the development of their human capital
The association of economic and cultural capital with the NEET rate: differential geographical and temporal patterns
No full textUsing data from 103 Italian provinces, we investigated the relationship between local/regional development, and NEET. We constructed an indicator of cultural capital and another of economic capital and we studied their relation with the NEET rate. Covariance Structure Analysis with Generalized Least Squares estimation was employed, considering a three time-points retrospective model. Results indicate a consistent protective effect of the economic capital on the NEET rate, both in the short run (2 years) and in the medium run (10 years). However, this effect has been obtained in the Central provinces (at 2 and 10 years) and Southern provinces (at 10 years), but not in the Northern provinces. A mediation analysis indicated that, historically, the cultural capital may partly mediate the effect of the economic capital. We did not detect a significant direct effect of the cultural capital on the NEET rate, which is strongly mediated by the action of the economic capital. Together, these results denote that the economic capital is a strong predictor of NEET, but not in very competitive economic areas
A study for the restoration of a platform-island oil terminal
No full textThe interest in off-shore multi-purpose platforms resides in the wide opportunities involved in it, for example considering the development of large marine infrastructure in the near future. An available off-shore site where testing marine energy converters (exploitation of wave, tidal and hydrokinetic energy, magnetohydrodynamic generator, linear converter) developing and implementing marine aquaculture, can short the gap to the next off-shore activities. Since near the city of Genova there is an abandoned but still well conserved and robust offshore island it is interesting evaluate the cost and intervention to restore it making it an ideal site to explore the new frontier offered by living the oceans off-shore. This paper deals with the restoration study of an existing off-shore structure for oil discharging operations sited 1 miles off the port of Multedo, in the city of Genova, propsing different exploitation scenario
Thermal Energy Storage technologies for the optimal management of metal hydride hydrogen storage systems
No full textHydrogen is an excellent energy carrier that could enable the energy transition, however, storing it in a proper and effective way is one of hydrogen key issues. Storing hydrogen via metal hydrides (MH) can be considered a potential solution to avoid problems (safety, pressurization/liquefaction costs) related to conventional storage systems. A thermal energy storage could be coupled to the MH one, to store the heat obtained from the hydrogen absorption reaction and subsequently to release it to start and support the desorption reaction. This technology allows not to use external sources of heat or of compression, guaranteeing significant energy savings. In this work a MH hydrogen storage system (coupled to a 1 MW electrolyser used in an industrial use case) is studied, focusing on its thermal management supported by a Latent Heat Thermal Energy Storage (LTES) via Phase Change Materials (PCM). The study analyses three different metal hydrides, namely LaNi5, TiFe, TiMn1.5, and phase change materials produced by Rubitherm® Technologies GmbH. A model representing a specific electrolyser case study is then built up, enabling the evaluation of the hourly behaviour of the integrated system, the sizing of the thermal energy storage and to conduct a sensitivity analysis towards the identification of most relevant geometry parameters which affect the techno-economic performances of the system, whose are reported in the concluding part of the paper
Thermoeconomic Analysis of Csp Air-Steam Mixed Cycles with Low Water Consumption
No full textAbstractStarting from a state of the art of CSP plants and the undergoing research in hybridization of Gas Turbine plants, the paper investigates alternative plant configurations particularly regarding the integration of CSP technology with mixed cycles because of their low water consumption and the possible use of current CSP components, assessed and compared with a through-life thermo-economic analysis
Towards innovative district energy management: A case study with stochastic renewable generators
No full textThe conversion of ocean wave power into sustainable electrical power represents a major opportunity to Nations endowed with such a kind of resource. At the present time the most of the technological innovations aiming at converting such resources are at early stage of development, with only a handful of devices close to be at the commercial demonstration stage. The Seaspoon device, thought as a large energy harvester, catches the kinetic energy of ocean waves with promising conversion efficiency, and robust technology, according to specific “wave-motion climate”. University of Genoa developed and patented a prototype to be deployed in medium average energy content seas (i.e. Mediterranean or Eastern Asia seas). This paper presents the installation phases of the first real scale prototype installed in the gulf of Genova and the monitoring of its performances. A brief description of the Seaspoon WEC is presented together with the monitoring equipment and procedures.In this research a thermoeconomic analysis of its integration in a real polygenerative district is also investigated. The impact of such this kind of stochastic renewable generator in the Savona Campus Smart Polygeneration Microgrid (SPM) is evaluated. The SPM plant is made up by (i) two auxiliary boilers (500kWth each), (ii) four micro gas turbines (30kWe, 2x65kWe and 100kWe), (iii) an internal combustion engine fed by natural gas (20kWe), (iv) an absorption chiller (100 kWf) and (v) PV panels for a total power installed of 100 kWe. Generators are “distributed” around the campus and they are coupled to electrical and thermal storages. Since the system is constituted by co-generative prime movers it can supply both electrical and thermal energy of the campus and the integration of storage is really important in order to follow both the requests, pursuing the best management strategy. The analysis of this smart-grid is performed exploiting a software developed by the Author's research group, which allows for the thermo-economic optimization of poly-generative energy systems. A model of the real plant was built and it was implemented in the software. The off-design curves of the real devices installed in the campus were used in order to increase the reliability of the simulation results. The grid was simulated considering the time dependent nature of the demands throughout the whole year. The model was used to simulate the smart grid behavior during the whole year, and find the best operational strategy. A time-dependent thermo-economic hierarchical approach has been used, considering the time-dependent electrical, thermal and cooling load demands during the year as problem constraints. The results are presented and discussed in depth and show the strong interaction between fossil and renewable resources, particularly the impact of unpredictable and randomized generators like the WECs ones. A dedicated model of the Seaspoon was implemented and exploited in the code
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
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
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