1,720,954 research outputs found
Numerical and Experimental Study of High‐Speed Laser Cutting of Copper Current Collectors: Process Optimization for Quality Assessment
Full text linkEnsuring high-edge quality in battery current collectors is crucial for improving battery performance and preventing potential safety issues. Defects such as uneven cuts, spatter, and excessive remelted zones can negatively impact the current collectors' electrical conductivity and mechanical integrity. Laser cutting offers advantages over mechanical methods by enabling faster processing, higher precision, and greater energy concentration. This study models and predicts defect occurrence under varying process parameters, focusing on the interaction between a single-mode continuous-wave (CW) laser and a copper current collector foil. Key factors influencing edge profile defects and cutting quality are investigated through experimental analysis and numerical simulation. A Computational Fluid Dynamics (CFD) model based on the volume of fluid method identifies parameters affecting the physical phenomena and optimal cutting conditions. Model validation is achieved by comparing experimental results across a range of process parameters associated with distinct defect formation modes. This model enables the prediction of defect types across a wide spectrum of laser speeds (2–25 m s−1), power levels (200–1000 W), and foil thicknesses (8–16 (Formula presented.)). Findings serve as a guideline for selecting process parameters when using current collectors of varying materials and thicknesses. © 2025 The Author(s). Advanced Materials Technologies published by Wiley-VCH GmbH
The Effect of Temperature on Magnetic Properties and Surface Integrity in Nd2Fe14B Permanent Magnets, Under Dry and Wet Grinding for Automotive Applications
Full text linkElectric motors transform the electrochemical energy into mechanical energy needed for the vehicles' motion. Given that the transition from internal combustion engines to electric vehicles is likely to be the main driver of sustainable transportation, high-performing electric motors will be increasingly important for this transition. Herein, the effect of the grinding process on the surface integrity and magnetic properties of NdFeB permanent magnets are investigated. NdFeB permanent magnets are most commonly used in the fabrication of permanent magnet electric motors and they are usually ground during their fabrication process chain in order to create a high-quality cylindrical rotor for subsequent mechanical assembly. In particular, the effects of wet and dry grinding processes on magnetic properties and surface integrity are studied and compared. Guided by a thermal model, the grinding process parameters are varied highlighting their effects on the underlying thermomechanical phenomena responsible for the changes in surface integrity and magnetic properties observed. Wet grinding proves to be a viable process for NdFeB magnets. Additionally, acceptable results are achieved with dry grinding, which is particularly appealing due to its sustainability. It is noteworthy that the range of process parameters yielding acceptable results is narrower
Progettazione termofluidodinamica di un dispositivo per la distribuzione di colla
No full textQuesta tesi si basa sul lavoro di tirocinio che ho svolto al laboratorio di fisica tecnica dell’università di Bologna in cui ho cercato di ottimizzare, con l’ottica di un efficientamento energetico, sia il lato termico che quello fluidodinamico di un distributore di colla attraverso simulazioni CFD. Partendo da un sistema di partenza con svariate problematiche che portavano a consumi energetici eccessivi e non giustificati, l’obbiettivo
finale è stato quello di proporre un apparato nuovo che ne ottimizzasse le prestazione, quelle cioè di un controllo sulla quantità di colla depositata da ogni ugello, riducendone
le variazioni nel tempo e tra gli ugelli stessi e un controllo sulla temperatura, andando a ridurre il più possibile i consumi.
È stato poi simulata la possibilità di inserire un mezzo poroso di tipo giroide all'interno del distributore per migliorare le performance termiche.
Il pezzo è stato infine stampato 3D tramite tecnica additive manufactory e verrà testato in laboratori
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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