324,187 research outputs found
Photovoltaic System Efficiency Enhancement With Thermal Management: Phase Changing Materials (pcm) With High Conductivity Inserts
No full textThe electrical conversion efficiency of photovoltaic cells from solar radiation heavily depends on the cell temperature. Here we propose a novel thermal management strategy to keep the cell temperature in the same order to attain maximum efficiency. The comparative study presented is based on four solar module configurations: a conventional photovoltaic module (PVT module), a conventional module with PCM layer underneath (PVT/PCM-I), a configuration where fins embedded into PCM (PVT/PCM-II), and configuration where the bottom of the PCM layer in PVT/PCM-II was cooled via convection (PVT/PCM-III). The developed 3D numerical model is solved via ANSYS software involving the solar ray tracing radiation model for incident solar radiations and a transient melting-solidification thermo-fluid model to cater for PCM phase transition. Results from the numerical model were validated via a comparison of experimentally studied results presented in the literature. After 120 minutes, results show that the conversion efficiency of PV cells becomes 16.84%, 18.65%, 18.83%, and 18.98% after 120 minutes for PVT module, PVT/PCM-I, PVT/PCM-II, and PVT/PCM-III with an inlet velocity of 3m/s, respectively. For the respective configurations, the specific electrical power per unit area produced reaches 75.30W/m2, 83.39W/m2, 84.19W/m2, and 89.42W/m2 for solar radiation of 540W/m2 and 26°C ambient temperature. Results reveal that a 5 mm increase in the fin height for PVT/PCM-II results in a 0.22% increase in efficiency while a 0.5m/s increase in the inlet velocity of the cooling air for PVT/PCM-III results in about 0.06% increase in efficiency. © 2021, ilhami Colak. All rights reserved
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Modeling of a smart grid system using real time data on NEPLAN
No full textThe simulation model of the Smart Grids Laboratory of the Institute of Energy and Transport is presented in this paper and a day of its operation is analyzed. The developed model simulates six different modules (a photovoltaic array, a Li-ion battery storage system, a small wind turbine, a diesel generator, a laboratory load and the connection point with the grid). The modules are connected radially at a common bus
Proceedings of World Academy of Science Engineering and Technology
No full textThe wavelet transform is one of the most important method used in signal processing. In this study, we have introduced frequency-energy characteristics of local earthquakes using discrete wavelet transform. Frequency-energy characteristic was analyzed depend on difference between P and S wave arrival time and noise within records. We have found that local earthquakes have similar characteristics. If frequency-energy characteristics can be found accurately, this gives us a hint to calculate P and S wave arrival time. It can be seen that wavelet transform provides successful approximation for this. In this study, 100 earthquakes with 500 records were analyzed approximately
Comparative analysis of on-load tap changing (OLTC) transformer topologies
No full textOld - EWI-ESE-DC&S DC systems & StorageElectrical Power Processin
The water-soluble zwitterionic and cationic tetra-substituted zinc(II) phthalocyanines: Synthesis, photophysical, photochemical and protein binding properties
No full textThe synthesis and characterization of tetra-(2-EN-((3-dimethylamino)propyl)carbamate]oxyethyl} substituted zinc(II) phthalocyanine (ZnPc) and its sulfobetaine (S-ZnPc), betaine (B-ZnPc), N-Oxide (N-ZnPc) and cationic (Q-ZnPc) derivatives were described in this study. All novel phthalocyanines were characterized by UV-Vis, FT-IR, H-1 NMR, mass spectroscopic techniques and elemental analysis as well. The solubility of these phthalocyanines was enhanced in polar solvents and aquatic media by the conversion of amidoamine groups on the substituents to the zwitterionic sulfobetaine, betaine, N-Oxide, and quaternary ammonium counterparts which make them promising candidates for treatment of cancer via photodynamic therapy (PDT) method. Although the photophysical and photochemical properties of newly synthesized tetra-{2-[N-((3-dimethylamino)propyl)carbamateloxyethyl} substituted zinc(II) phthalocyanine (ZnPc) was investigated in DMSO, its zwitterionic and cationic derivatives were examined in both DMSO and aqueous solutions. The binding behavior of zwitterionic and cationic zinc(II) phthalocyanines were investigated by bovine serum albumin (BSA) protein in aqueous solutions for determination of transportation abilities of these phthalocyanines in the blood. (C) 2016 Elsevier Ltd. All rights reserved
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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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No full textCan archives of audiovisual TV interviews be used to make authors more visible to students, and thereby reduce the learning gap between native and non-native language speakers in college classes? We examined students in a college course who learned about one scholar's ideas through watching an audiovisual TV interview (i.e., visible author format) and about another scholar's ideas through reading a formal text description (i.e., invisible author format). For the invisible author, native language speakers scored significantly higher than the non-native language speakers on a corresponding exam question (i.e., a cognitive measure), generated more words on the exam question (i.e., a motivational measure), and mentioned the author's name more often in answering the exam question (i.e., an affective measure). For the visible author, the groups did not differ on any of these measures. These findings provide evidence for the idea that making the author visible through audiovisual TV interviews can eliminate the learning gap between native and non-native language speakers. 3 Universities around the world serve students who are non-native speakers of th
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