1,721,001 research outputs found
Energy, ECOS 2007 Special Issue
No full textThis special issue of Energy - The International Journal contains selected and re-reviewed papers presented at the International Conference ECOS 2007 (Efficiency, Costs, Optimization, Simulation and Environmental Impactof Energy Systems), which was held in Padova, Italy, on June 25-28, 2007. The ECOS Conferences were born in 1987, when the first one was held in Rome, even though the name ECOS was used for the first time in the 1992 edition. So, ECOS 2007 was the 20th edition of the conference; and this is the main reason why Italy was chosen for the 20th anniversary. Padova, better known as Padua in the international environment, is a very ancient city, rich in history; and its university, established in 1222, one of the oldest in the world, has given an important contribution, along the centuries, to the human, social and scientific culture.
In fact ECOS 2007 was organized by the University of Padova, c/o the Department of Mechanical Engineering, with the cooperation of ASME (American Society of Mechanical Engineers) and ICAT (International Centre for Applied Thermodynamics) and the sponsorship od Baxi SpA, Siram SpA, Pedrollo SpA, MAN Nttzfahrzeuge Vertrieb Sud AG, Adriatic LNG, Unindustria Padova, SIT Group, APS Holding, SITA SpA, ATI.
After 20 years, ECOS has become a classical meeting of experts and also friends, engaged in energetic and environmental research, with interest to the economic aspects also. At the beginning of the third millennium, a close interaction between science and technology is needed in this field; and it is significant that a fair number of papers of ECOS 2007 have been presented by industry representatives, who showed advanced practical applications related to the concepts od sustainable development and rational use of energy resources. Under this frame, Energetics can be looked at as Energ-Ethics!
About 190 papers (besides 3 invited lectures), coming from more than 30 countries, were presented at the conference and included in the proceedings, after a careful review process. This special issue contains some of these papers, selected by the Editorial Board and improved after further reviews. They cover some of the most important topics in the field of energy and the environment.
We must warmly than professor Ozer Arnas, co-chairman of ECOS 2007, who made a very valuable contribution to the success of the conference; and many thanks also to the members of the Editorial Board and all the reviewers of both the conference and this special issue
Analysis and comparison of different thermal cycles for power generation in space
No full textThis paper presents an analysis of solar-heat driven Brayton and Rankine power cycles operating in space with different working fluids. State of the art literature show that generation of power in space for terrestrial use can represent a great opportunity in the future for many reasons, including the facts that (1) the lowtemperature of space, - 3K, which acts as the power system heat sink, allows the attainment of very high efficiency even with low-temperature heat inputs, and (2) the solar energy input is higher than on earth, all this while using traditional cycles. This study is focused on analysis and comparison of performance of advanced Brayton and Rankine cycles operating under space conditions, with a main objective to advance the identification of system configurations, working fluids and conditions leading to the design of space power systems that combine high efficiency and low weight. Starting from previous studies that show the potential high efficiency of the use of diatomic gases (H2, N2) in regenerative Brayton and Rankine cycles we have presented a comparative analysis of different and more advanced Brayton and Rankine configurations to advance the understanding of the optimal trade-off between high efficiency (thermal and exergetic) and the smallest needed heat rejection exchanger area. The effect of the main cycles' operational parameters such as pressure ratio, turbine inlet temperature, working fluid mixture and different plant layouts on thermal and exergy efficiency and power to radiator area ratio have been analyzed. Under the examined conditions the thermal efficiency of regenerative - reheated-intercooled Brayton, that resulted being the best Brayton choice, reaches 71.8% while the efficiency of the reheated-regenerative Rankine cycle reaches 88.9%, both significantly higher than the previously analysed cycles taken as reference. The power/(radiator area) ratio, however, was an order of magnitude higher for the reheated-intercooled Brayton cycle, which may lead to lower costs of the generated power. This ratio was also found to increase with the introduction of reheating for both the Rankine and Brayton cycles, while the Interceding was in all cases disadvantageous
Advances in Energy Studies. Exploring supplies, Constraints and Strategies. Editorial Introduction
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
