1,720,962 research outputs found
Bismuth sulfide and PEDOT: PSS as cost effective counter electrode materials for Dye-Sensitized Solar Cells
No full textPresented to the 16th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held online, Wichita State University, May 1, 2020.Research completed in the Department of Mechanical Engineering, College of EngineeringAs the energy infrastructure of nations is moving to renewable energy sources out of concern of climate change, solar energy appears to be a large exploitable resource that can be harnessed on a large scale. However, the cost of producing ultra-pure silicon (Si) ingots for the use in the manufacture of commercial silicon photovoltaics prevents the cost of electricity produced from being competitive with the fossil fuel-based energy production. An alternative to Si based solar cells would be Dye-Sensitized Solar Cell (DSSC), which are low cost, easy to manufacture and can be made semi-flexible. A DSSC is generally composed of three parts, a photo-electrode, an electrolyte and a counter electrode. Under illumination, the photoelectrode which contains complex photosensitizers, which releases an electron which is transported to the external load, leaving the photoelectrode in an oxidized state. The electrons are collected by the counter electrode and used to reduce the electrolyte. This charged electrolyte then reduces the positively charged photo-electrode, allowing the process to begin again. In this poster presentation, we will showcase the use of Bismuth Sulfide (Bi2S3) and PEDOT: PSS, which is conductive polymer, as a means of reducing materials cost of DSSC, replacing more expensive counter electrode materials such as platinum and ruthenium.Graduate School, Academic Affairs, University Librarie
Design and synthesis of bismuth sulfide and exploration of it’s application as a photo-electrode material in third generation solar cells
No full textThesis (M.S.)-- Wichita State University, College of Engineering, Dept. of Mechanical EngineeringSince energy production for day to day use is moving towards renewable energy sources
as these sources become more economically viable, while being less polluting to operate. Solar
energy has become one of the major sources of renewable energy. However, it currently relies
on ultra-pure silicon ingots to produce commercial silicon photovoltaics, which prevents the
cost of electricity being produced to compete with non-renewable energy production.
A viable low cost alternative for silicon based cells would be dye-sensitized solar cells
(DSSC), which are easier and cheaper to manufacture as they do not require expensive and
delicate raw materials to make, while they could be made semi-flexible which allows for a
greater variety of applications for these cells.
A DSSC consists three components, a photo-electrode, an electrolyte and a counterelectrode.
When exposed to incident light, the photoelectrode which contains complex photosensitizers,
which releases an electron which is transported to the external load, leaving
the photoelectrode in an oxidized state. The electrons are collected by the counter electrode
and used to reduce the electrolyte. This charged electrolyte then reduces the positively
charged photo-electrode, allowing the process to begin again. To improve the efficiency of
this process, we explore the use of Bismuth Sulfide and Titanium Oxide composite as photoelectrode
material by testing it in varying ratios and studying their impact on the efficiency
of DSSC
Bismuth Sulfide and Titanium Oxide as photo-electrode materials for dye sensitized solar cells
No full textPresented to the 17th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held online, Wichita State University, April 2, 2021.Research completed in the Department of Mechanical Engineering, College of EngineeringEnergy production for day-to-day use is moving towards renewable energy sources due to them becoming more economically viable, while being less polluting to operate. Solar energy has become one of the major sources of renewable energy. However, it currently relies on ultra-pure silicon ingots to produce commercial silicon photovoltaics, which prevents the cost of electricity being produced to compete with non-renewable energy production. A viable low-cost alternative for silicon based cells would be dye-sensitized solar cells (DSSC), which are easier and cheaper to manufacture as they do not require expensive and delicate raw materials to make, while they could be made semi-flexible which allows for a greater variety of applications for these cells. A DSSC consists three components, a photo-electrode, an electrolyte and a counter-electrode. When exposed to incident light, the photoelectrode which contains complex photosensitizers, which releases an electron which is transported to the external load, leaving the photoelectrode in an oxidized state. The electrons are collected by the counter electrode and used to reduce the electrolyte. This charged electrolyte then reduces the positively charged photo-electrode, allowing the process to begin again. To improve the efficiency of this process, we explore the use of Bismuth Sulfide and Titanium Oxide composite as photo-electrode material by testing it in varying ratios and studying their impact on the efficiency of DSSC.Graduate School, Academic Affairs, University Librarie
Application of polymer derived ceramics for 3D printing thermal management systems
No full textPoster project completed at the Wichita State University Department of Mechanical Engineering. Presented at the 21st Annual Capitol Graduate Research Summit, Topeka, KS, March 21, 2024.Manufacturing parts with complex geometry which are mechanically stable at high temperatures for different applications is challenging problem in the aerospace industry. A class of materials which has potential in this application are called Polymer Derived Ceramics (PDCs). These PDCs are made by heat treatment of silicon-based polymers such as polysiloxanes which produce Silicon OxyCarbides. These ceramics can be tuned to have specific mechanical, thermal or electrical properties along with good shape fidelity based on formulation of the polymer and the filler material used. Additive manufacturing or 3D printing the complex structures using Direct Ink Writing allows us to print parts with tuneable properties based on the fillers used in the feedstock, using equipment and methods that differ only a little from the more established Fused Deposition Modelling (FDM) printers that people are more familiar with. To establish predictive models on the printability of the feedstock and it's accuracy in generating the desired structure, our work currently focuses on developing relationships between printing parameters and the resulting printed object
Organic conjugated polymers and polymer dots as photo-catalysts for hydrogen production
No full textClick on the DOI link to access the mini review (may not be free).Owing to the outstanding characteristics of tailorable electronic and optical properties, semiconducting polymers have attracted considerable attention in recent years. Among them, organic polymer dots process large breadth of potential synthetic diversity are the representative of photocatalysts for hydrogen production, which presents both an opportunity and a challenge. In this mini-review, first, the organic polymer photocatalysts were introduced. Then, recent reports on polymer dots which showed a superior photocatalytic activity and a robust stability under visible-light irradiation, for hydrogen production were summarized. Finally, challenges and outlook on using organic polymer dots-based photocatalysts from hydrogen production were discussed.This work was supported by ACS Petroleum Research Fund (PRF # 59716-DNI10)
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
Variations on the Author
No full text“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
No full textWe 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
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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