1,720,959 research outputs found
Seasonal Variation of Internal Parameters of an Amorphous Silicon (a-Si) Thin Film Photovoltaic Module
No full textEKE, Rustu/0000-0002-4943-6644; EKE, Rustu/0000-0002-9260-6143WOS: 000215015900002Operating parameters of a KA58 Amorphous Silicon (a-Si) photovoltaic module is investigated as a function of solar irradiation and atmospheric conditions using current-voltage curves taken for a year from April to May at Mugla Sitki Kocman University PV Outdoor Test Site. Single diode model is proposed to explain the current-voltage curves of thin film solar cells and modules. It is observed that the operating parameters of a KA58 a-Si photovoltaic module exhibit significantly different response to the changes in solar radiation and weather conditions in a period of 12 months. Correlations between internal parameters, namely R-S, R-P, I-L, I-O and a (modified ideality factor) of module and solar irradiation and atmospheric data is investigated
Partially shaded characterization effect on two different single crystalline photovoltaic modules with bypass diode
No full textEKE, Rustu/0000-0002-4943-6644; EKE, Rustu/0000-0002-9260-6143WOS: 000316431300002One of the main causes of losses in energy generation within photovoltaic (PV) systems is the partial shading on photovoltaic modules. A PV system can easily lose a significant portion of its total output with only minimal shading. A bypass diode in the module will form an alternating path for the current generated from the unshaded parts and prevent these cells/modules from damage in the array. Because solar cells are not designed to support a reverse voltage, they may be degraded, depending on the applied voltage. Virtually all modern PV modules include bypass diodes. The purpose of this work is the study of power decrease of a commercially available single-crystalline silicon photovoltaic module under varying shading with bypass diode. Without shading the tested module generates 75W and 120 W at maximum power under rated conditions
Design and implementation of a low-cost multi-channel temperature measurement system for photovoltaic modules
No full textEKE, Rustu/0000-0002-4943-6644; EKE, Rustu/0000-0002-9260-6143WOS: 000304642400017An efficient and low-cost temperature logging system with a 16-channel input was developed for measurements of photovoltaic module temperature. This paper reports the principle of operation, design aspects, as well as the experimentation and performance of the simultaneous temperature measurement of 16 solar cells/modules. The system consists of a 16 channel multiplexer, a 12 bit AID, a differential amplifier and NTC temperature sensors. The temperature range of the sensor is from -20 degrees C to 120 degrees C. The simplistic design requires no large internal memory to store data but incorporates a high degree of sensitivity and dynamic range (according to climate condition), thus the cost of the design remains low and makes it suitable for field applications. The system was successfully tested for the operating temperature of a 40-cell mono crystalline Si photovoltaic module under realistic outdoor conditions during a summer and a winter day. The temperature Instrumentation developed for avoidance of special interface card use enabled the successful collection of data from long distances with negligible level of noise. (C) 2012 Elsevier Ltd. All rights reserved
Predicting the energy yield of a photovoltaic system from an individual photovoltaic module
No full text3rd Turkish Solar Electricity Conference and Exhibition (SolarTR) - APR 27-29, 2015 - Ankara, TURKEYSenturk, Ali/0000-0001-7033-2957; EKE, Rustu/0000-0002-4943-6644; EKE, Rustu/0000-0002-9260-6143WOS: 000372057300018In this study, energy yield of a photovoltaic (PV) system is predicted from the output peak power of an individual PV module. Measured energy yield of an individual back contact single crystalline silicon PV module is scaled with total number of PV module within the PV array to calculate the energy yield. Regarding the conversion efficiency of the inverter in the PV system, calculated and measured energy yield of PV system were compared for selected dates. To confirm the accuracy of the proposed model, days with clear and cloudy irradiation profile were selected from August and November. The difference between calculated and measured energy yield of PV array were found to be insignificant. Thus, current method which is straightforward, feasible and reliable to predict the energy yield of PV array using just an individual PV module. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimAselsan A S, Turkiye Sise Cam Fabrikalari A S, Halk Enerji Yatirimlari Uretim Ins Taahhut Tic San A S, Dorutek Teknoloji Ltd Sti, Seiso Enerji Sis Muh San Tic A S, GTC Dis Ticaret Ltd Sti, Air Liquid
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
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