1,720,966 research outputs found
A computational approach for the design of high-power performance Proton Exchange Membrane fuel cells.
No full textNumerical Modeling of Electrochemical and Mechanical Intercalations in All Solid-State Lithium-Ion Batteries
Full text linkThe rapid development of new technologies in recent decades has caused an ever increasing demand for energy storage devices that are lightweight, durable, and maintain high life-cycle expectancies. Lithium-ion batteries have emerged as a universal solution due to their exceptional energy storage and high power delivery. Lithium-ion batteries based on organic electrolytes suffer from safety concerns; specifically flammability, low temperature thresholds, and coupled electrochemical-mechanical degradation. From a design perspective, introducing a new type of lithium-ion battery with enhanced storage capacity, safe and reliable performance is the most ongoing challenge in battery research communities. This research focuses on the numerical modeling of electrochemical and mechanical interactions in all solid-state lithium-ion batteries. In particular, we present physical and numerical modeling frameworks to model and understand the electrochemical and mechanical performance of all solid-state lithium-ion batteries under the influence of some electrochemical and mechanical degradation phenomena. To this end, we developed finite element modeling frameworks based on multi-scale and full resolution modeling methods. These models facilitate detailed understandings and comprehensive studies of the behavior of lithium-ion batteries under the evolution of degradation phenomena. While our model is not limited to any particular battery system and failure mechanism, we focus on the evaluation of the electrochemical performance of both thin and bulk solid-state lithium-ion batteries, stress-diffusion-damage coupling effects in the electrode active materials and interfacial debonding effects in the battery cell. The involved coupled physical phenomena includes mechanical deformation, diffusion-migration processes, stress-diffusion-damage coupling, electrochemical surface reactions, and cohesive zone model. To provide a predictive numerical tool for optimizing the performance of battery cell, our finite element model is augmented with a parameter identification method. The parameter identification method provides unique opportunities for parametric study and identifying key design parameters in the life-time performance of all solid-state lithium-ion batteries.The characteristics of the research are explored by presenting comprehensive numerical examples. The presented numerical examples illustrate the performance of the battery cell under the influence of different physical phenomena. We verified and calibrated the accuracy and stability of the developed framework by numerical and experimental examples. The parameter identification method is applied for parametric study and error minimization in the battery. The results revealed the great influence of material properties and geometric configuration on the electrochemical performance of the battery cell. The influence of damage evolution on the mechanical and electrochemical performance of the battery is explored by numerical examples. The results showed that diffusion-damage coupling has significant influences on the life-time performance of the battery cell. The results of cohesive zone modeling revealed the main contribution of the interface properties on the separation and the debonding phenomena at the interface of multi-phase material.</p
Numerical Modeling of Electrochemical and Mechanical Intercalations in All Solid-State Lithium-Ion Batteries
Full text linkThe rapid development of new technologies in recent decades has caused an ever increasing demand for energy storage devices that are lightweight, durable, and maintain high life-cycle expectancies. Lithium-ion batteries have emerged as a universal solution due to their exceptional energy storage and high power delivery. Lithium-ion batteries based on organic electrolytes suffer from safety concerns; specifically flammability, low temperature thresholds, and coupled electrochemical-mechanical degradation. From a design perspective, introducing a new type of lithium-ion battery with enhanced storage capacity, safe and reliable performance is the most ongoing challenge in battery research communities. This research focuses on the numerical modeling of electrochemical and mechanical interactions in all solid-state lithium-ion batteries. In particular, we present physical and numerical modeling frameworks to model and understand the electrochemical and mechanical performance of all solid-state lithium-ion batteries under the influence of some electrochemical and mechanical degradation phenomena. To this end, we developed finite element modeling frameworks based on multi-scale and full resolution modeling methods. These models facilitate detailed understandings and comprehensive studies of the behavior of lithium-ion batteries under the evolution of degradation phenomena. While our model is not limited to any particular battery system and failure mechanism, we focus on the evaluation of the electrochemical performance of both thin and bulk solid-state lithium-ion batteries, stress-diffusion-damage coupling effects in the electrode active materials and interfacial debonding effects in the battery cell. The involved coupled physical phenomena includes mechanical deformation, diffusion-migration processes, stress-diffusion-damage coupling, electrochemical surface reactions, and cohesive zone model. To provide a predictive numerical tool for optimizing the performance of battery cell, our finite element model is augmented with a parameter identification method. The parameter identification method provides unique opportunities for parametric study and identifying key design parameters in the life-time performance of all solid-state lithium-ion batteries.The characteristics of the research are explored by presenting comprehensive numerical examples. The presented numerical examples illustrate the performance of the battery cell under the influence of different physical phenomena. We verified and calibrated the accuracy and stability of the developed framework by numerical and experimental examples. The parameter identification method is applied for parametric study and error minimization in the battery. The results revealed the great influence of material properties and geometric configuration on the electrochemical performance of the battery cell. The influence of damage evolution on the mechanical and electrochemical performance of the battery is explored by numerical examples. The results showed that diffusion-damage coupling has significant influences on the life-time performance of the battery cell. The results of cohesive zone modeling revealed the main contribution of the interface properties on the separation and the debonding phenomena at the interface of multi-phase material.</p
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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