1,720,970 research outputs found
Performance analysis of a small scale solar cooling plant based on experimental measurements
No full textThe main scope of the paper is analyzing the experimental data and evaluating the techno-economic feasibility of a solar cooling plant with solar thermal concentrators for residential application in Central Italy. An extensive monitoring of a solar cooling system was carried out in Forlì (Italy) in the summer of 2014 and 2015. The solar cooling plant was remotely monitored and data on environmental conditions, fluids flowrate and temperatures and both heating and cooling power production were continuously acquired and stored. The results showed that the combination of solar thermal concentrator and absorption chiller can simultaneously satisfy the demand for domestic hot water production and space cooling. Nevertheless, the solar thermal concentrator proved limited efficacy due to suboptimal environmental framework conditions and to low reliability. A preliminary economic analysis has been carried out for a residential application through the Net Present Value method. The Net Present Value has been computed for different effectiveness of the solar cooling plant in meeting the demand for domestic hot water production and space cooling. The results show that i) an investment reduction in comparison to the costs of the experimental plant and ii) incentives are fundamental to make the solar cooling plant profitable
Technological and non-technological barriers in the revamping of traditional district heating networks into low temperature district heating: an Italian case study
No full textThe revamping of existing high temperature district heating systems with low temperature solutions will ensure a better usage of primary energy thanks to the reduction of thermal losses through the networks and to the possibility of use low grade enthalpy heat for the scope, including renewables. However, several criticalities are present that make the evolution from the 3rd to the 4th generation of district heating not immediate
Modification of Fraser’s Method for the Atmospheric CO2 Mass Estimation by Using Satellite Data
Full text linkOne of the most critical greenhouse gases in the atmosphere is carbon dioxide (CO2) due to its long-lasting and negative impact on climate change. The global atmospheric monthly mean CO2 concentration is currently greater than 410 ppm which has changed dramatically since the industrial era. To choose suitable climate change mitigation and adaptation strategies it is necessary to define carbon dioxide mass distribution and global atmospheric carbon dioxide mass. The available method to estimate the global atmospheric CO2 mass was proposed in 1980. In this study, to increase the accuracy of the available method, various observation platforms such as ground-based stations, ground-based tall towers, aircrafts, balloons, ships, and satellites are compared to define the best available observations, considering the temporal and spatial resolution. In the method proposed in this study, satellite observations (OCO2 data), from January 2019 to December 2021, are used to estimate atmospheric CO2 mass. The global atmospheric CO2 mass is estimated around 3.24 × 1015 kg in 2021. For the sake of comparison, global atmospheric CO2 mass was estimated by Fraser’s method using NOAA data for the mentioned study period. The proposed methodology in this study estimated slightly greater amounts of CO2 in comparison to Fraser’s method. This comparison resulted in 1.23% and 0.15% maximum and average difference, respectively, between the proposed method and Fraser’s method. The proposed method can be used to estimate the required capacity of systems for carbon capturing and can be applied to smaller districts to find the most critical locations in the world to plan for climate change mitigation and adaptation
Classification through analytic hierarchy process of the barriers in the revamping of traditional district heating networks into low temperature district heating: An Italian case study
Full text linkThe revamping of existing high temperature district heating systems with low temperature solutions will ensure a better usage of primary energy thanks to the reduction of thermal losses through the networks and to the possibility of using low grade enthalpy heat for the purpose, including renewables and waste heat. However, several criticalities are present that make the evolution from the 3rd to the 4th generation of district heating not immediate. The paper aims to identify general technological and non-technological barriers in the revamping of traditional district heating networks into low temperature ones, with a particular focus on the Italian framework. Possible solutions are suggested, including relevant advice for decision makers. The paper also analyses how the possible solutions required for the up-grade of the existing district heating network can be classified through the Analytic Hierarchy Process (AHP) to prioritize the ones that prove best for more advanced evaluation. © 2019, Aalborg University press. All rights reserved
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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
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