1,721,060 research outputs found
Attività Antimicrobica e Caratterizzazione Spettroscopica di Complessi del Cu(II) con Fenantroline
No full textThe role of the power/efficiency misconception in the rebound effect's size debate: Does efficiency actually lead to a power enhancement?
No full textThis paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument. © 2008 Elsevier Ltd. All rights reserved
On the relationship between energy efficiency and complexity: Insight on the causality chain
Full text linkThe relationship between the energy efficiency, energy density and complexity level of the system is here addressed from both thermodynamic and evolutionary perspectives. A case study from economic systems is presented to show that, contrary to widespread opinion, energy efficiency is responsible for energy growth and the complexity leap. This article further examines to what extent complexity, on a historical time scale, may evolve to counterbalance conservative effects brought about by energy efficiency. We analyze structural complexity growth by four different paradigms. An evolutionary pattern is then proposed that may encompass the broad dynamics underlying complexity growth. This evolutionary pattern rests on the hypothesis that thermodynamic evolutionary systems are featured from an ever growing influx of energy driven into the system by self-catalytic processes, which must find its way through the constrains of the system. The system initially disposes of the energy by expanding, in extent and in number of components, up to saturation due to inner or outer constraints. The two counteractive forces, constraints and growing energy flux, expose the systems to new gradients. Every new gradient upon the system represents a symmetry rupture in components' space. By exploring a new gradient, the system imposes further restrictions on its components and increases its overall degree of freedom. © 2008 WIT Press
Evaluation of the energy efficiency evolution in the European road freight transport sector
No full textIn this paper, we evaluate energy efficiency in the European freight transport sector over three decades, according to a variety of indicators, methodologies and databases. The aim is, on the one hand, of determining major drawbacks in energy efficiency metrics, on the other hand, identifying a possible trend in the sector. The present analysis shows that energy efficiency evaluation is generally subject to misinterpretation and distortion with regard to the methods and data source adopted. Two different indicators (energy intensity and fuel economy) were initially taken into account to select the most suitable for evaluating vehicles' efficiency. Fuel economy was then adopted and measured according to two different methodologies (top-down and bottom-up). We then considered all the possible sources of distortion (data sources employed, methods of data detection, speed of detection, power enhancement, size factor) with the aim of accomplishing a sound estimation. Fuel economy was eventually divided with the maximum power available (adjusted fuel economy), to account for the power shift of vehicles, that represents a further efficiency improvement. © 2009 Elsevier Ltd. All rights reserved
Uno Studio sulle Caratteristiche strutturali e redox di complessi ternari del rame con proprietà auxiniche
No full textSynthesis, Spectroscopic and X-Ray Structure Characterization of Copper(II) Ternary Complexes
No full textCoordination Modes of Histidine Moiety in Copper(II) Dipeptide Complexes Detected by Multifrequency ESR
No full textThe evolution of the dye sensitized solar cells from Grätzel prototype to up-scaled solar applications: A life cycle assessment approach
No full textEmerging photovoltaics has gathered much attention in the last years. Among the innovative technologies developed in order to decrease the costs and broaden the applicability of photovoltaics, the dye sensitized solar cells have gained a flourishing interest for their potential as an economically and environmentally viable alternative to traditional devices. With the aim to increase the efficiency, stability and lifetime of dye sensitized solar cells, the research and development activity has been very productive in order to find the proper set of materials and the best architectures. This present paper aims to trace the progress of dye sensitized solar cells from a life cycle assessment perspective in order to draw the environmental profile of this technology for assessing its potential for eco-friendly innovation in the energy sector. The analysis is performed with a cradle-to-gate approach on three different levels: the synthesis of the solar cell main components, the fabrication of modules with different configurations and, finally, the operational phase of a roof-top photovoltaic system. The comprehensive ReCiPe impact assessment method along with the Cumulative Energy Demand, Global Warming Potential and Energy Payback Time indicators were employed to calculate the photovoltaic performances in comparison with other more mature and best-established thin film technologies. Major outcomes, presented along with a statistical analysis, show that dye sensitized solar cells compare similarly and sometimes better than inorganic devices, even for a far-from-optimum industrial fabrication procedure. Such investigation allows pointing out the usefulness of the life cycle assessment methodology to highlight benefits and drawbacks associated with different technical options that have been proposed for the development of the dye sensitized solar cells technology so fa
Data analysis of atmospheric emission from geothermal power plants in Italy
Full text linkElectric production from geothermal energy is still little exploited compared to its large potential and to the World renewable energy production from other sources. Some countries have exploited this energy source in order to enhance their transition to renewables. Today the largest geothermal energy producers in the world are New Zealand, U.S.A, Mexico, Philippines, Italy, Iceland, and, more recently, Turkey (Geothermal, 2012). Differently from other renewable sources, geothermal energy produces impacts on the environment that are very site-specific because of the nature of the resource and its geological characteristics Bravi et al.,2010; Parisi et al.,2013. In the same way, the atmospheric emissions associated to the activity of geothermal power plants for electric or heat production (mainly CO2, H2S, NH3, Hg, CH4) are also site-specific. In fact, due to technological and geographical differences among the geothermal installations operating all over the World, it is quite impossible to identify and attribute typical emission patterns, to perform forecasts valid for multiple sites or to collect universal data. Furthermore, it is virtually impossible the comparison among technologies located in different regions or countries. Definitively, inventories of primary data, as accurate and complete as possible, are essential to correctly evaluate the peculiarities of geo-thermoelectric energy production Parisi et al.,2018. Data reported here try to fill the gap in respect to the Italian situation. To this end, a complete survey of the atmospheric emissions from all the geothermal power plants in operation in the Tuscany Region is performed. In addition to data reporting, also some statistical analysis is performed to process data and to operate a further level of simplification which averages the emissions on the basis of geothermal sub-areas. The data collected is related to the research article “Life cycle assessment of atmospheric emission profiles of the Italian geothermal power plants” Parisi et al.,2019
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