1,720,964 research outputs found
Numerical analysis of a concentrating solar power plant integrating solid thermal storage systems for biofuel production
No full textReplacing hydrocarbons with biofuels will be a key step in the global decarbonisation process. Among the various biomasses, microalgae represent a particularly sustainable biological resource that can be used for the production of biofuels. In this study, a new concentrating solar power plant scheme that can be integrated with chemical reactors in which the hydrothermal processes for liquefaction of microalgae take place is proposed. The energy efficiency of the proposed plant scheme, which contemplates the use of concrete sensible heat storage systems, was analysed by means of hourly numerical simulations conducted using a specially developed TRNSYS model
Modelling the thermophysical properties of pavement layers using real-time sensor-collected data
No full textThe increase in in asphalt pavement temperatures due to solar energy absorption contributes to the urban heat island effect (UHI) and causes deformation and accelerated aging of their materials. Volumetric heat capacity (Cv), thermal conductivity (λ), surface albedo, and emissivity are the thermophysical properties that control these thermal variations. A new method is presented for determining Cv and λ parameters using in-situ thermal measurements and numerical models solving the heat conservation equation. This approach has the advantage of easily determining the variations of these properties over time, that is necessary to estimate the age-related performance of the asphalt layers. The method was used to characterize the intermediate layers temperature of the pavement in a smart parking structure at the University of Palermo, Italy. The numerical model calibrated with the parameters assessed by the proposed method can predict the temperature variations of the studied pavement layers with great accuracy
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
Development of Neural Network Prediction Models for the Energy Producibility of a Parabolic Dish: A Comparison with the Analytical Approach
Full text linkSolar energy is one of the most widely exploited renewable/sustainable resources for electricity generation, with photovoltaic and concentrating solar power technologies at the forefront of research. This study focuses on the development of a neural network prediction model aimed at assessing the energy producibility of dish–Stirling systems, testing the methodology and offering a useful tool to support the design and sizing phases of the system at different installation sites. Employing the open-source platform TensorFlow, two different classes of feedforward neural networks were developed and validated (multilayer perceptron and radial basis function). The absolute novelty of this approach is the use of real data for the training phase and not predictions coming from another analytical/numerical model. Several neural networks were investigated by varying the level of depth, the number of neurons, and the computing resources involved for two different sets of input variables. The best of all the tested neural networks resulted in a coefficient of determination of 0.98 by comparing the predicted electrical output power values with those measured experimentally. The results confirmed the high reliability of the neural models, and the use of only open-source IT tools guarantees maximum transparency and replicability of the models
Energy and Environmental Assessment of a Hybrid Dish-Stirling Concentrating Solar Power Plant
Full text linkAlthough the 2019 global pandemic slowed the growing trend of CO2 concentrations in the atmosphere, it has since resumed its rise, prompting world leaders to accelerate the generation of electricity from renewable sources. The study presented in this paper is focused on the evaluation of the energy and environmental benefits corresponding to the hypothesis of hybridizing a dish-Stirling plant installed on the university campus of Palermo (Italy). These analyses were carried out by means of dynamic simulations based on an accurate energy model validated with the experimental data collected during the measurement campaign that occurred during the period of operation of the reference plant. Assuming different scenarios for managing the production period and different fuels, including renewable fuels, it was found that the annual electricity production of the dish-Stirling system operating in solar mode can be increased by between 47% and 78% when hybridized. This would correspond to an increase in generation efficiency ranging from 4% to 16%. Finally, assuming that the dish-Stirling system is hybridized with renewable combustible gases, this would result in avoided CO2 emissions of between approximately 1594 and 3953 tons over the 25-year lifetime of the examined plant
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
Digital Twin-Based Assessment Framework For Monitoring Visual Comfort
No full textA digital twin is a virtual depiction of a real-world building environment. The ongoing rapid development of the sensor system and the database is expediting the creation of a digital twin. The decision support system that incorporates digital twins is anticipated to aid designers and operators in establishing an optimal design and control strategy. This study addresses this gap by applying Digital Twin technology to optimize visual comfort in a real-world laboratory setting. The research integrates theoretical understanding of visual ergonomics with practical application, using a case study approach. The objective was to develop a Digital Twin model that simulates critical visual comfort parameters (e.g. illuminance levels, Daylight Factor and glare conditions). The case study is the Solarlab locate in the Engineering Department of the University of Palermo. This study aims to demonstrates the impact of Digital Twin technology in enhancing visual comfort within indoor environments. Through innovative applications in a laboratory setting, it highlights the potential of Digital Twins in optimizing lighting and shading systems, thereby contributing significantly to energy efficiency and user well-being
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