1,720,971 research outputs found
Directing Surface Functions by Inducing Ordered and Irregular Morphologies at Single and Two-Tiered Length Scales
No full textSurface topography outlines material's interaction with its immediate environment. Herein, a series of cost-effective and scalable treatments are used to obtain single-scale and two-tiered surfaces with ordered/disordered arrangements of micro and nano features. The applied treatments induced a wide variety of surface features regarding length scale and arrangement. The individual and synergistic contributions of roughness length scale, regularity, and hierarchy are analyzed on surface functionalities. The performance of further functionalized and lubricant-infused surfaces is evaluated regarding their interaction with wetting media, as well as tribological and electrochemical resistance. The hierarchical surfaces show improved wear and corrosion resistance. The prominence of the surface features’ length scale and orderedness varies based on the loading conditions and test environments. Wettability is mainly directed by micro-scale features. Tribology is largely led by the ability of the surfaces in forming a stable low-surface-energy liquid interface. Electrochemical activity is primarily influenced by the synergic barrier effect of the nano-features and the infused lubricant regardless of their arrangement. The results indicate that combining the distinctive and complementary role of micro and nano features can offer the possibility of obtaining versatile multifunctional surfaces with tunable performances based on the expected in-service conditions
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
Accelerated biodegradation and improved mechanical performance of pure iron through surface grain refinement
No full textPure iron and its biocompatible and biodegradable alloys have a high potential to be used for temporary load bearing medical implants. Nevertheless, the formation of passive iron oxide and hydroxide layers, which lead to a considerably low degradation rate at the physiological environment, has highly restricted their application. Herein we used numerical and experimental methods to evaluate the effect of severe shot peening, as a scalable mechanical surface treatment, on adjusting the performance of pure iron for biomedical applications. The developed numerical model was used to identify the range of peening parameters that would promote grain refinement on the pure iron surface. Experimental tests were then performed to analyze the gradient structure and the characteristics of the interface free surface layer created on peened samples. The results indicated that severe shot peening could notably increase the surface roughness and wettability, induce remarkable surface deformation and grain refinement, enhance surface hardness and generate high in-depth compressive residual stresses. The increased surface roughness besides the high concentration of micro cracks and dislocation density in the grain refined top layer promoted pure iron's degradation in the biologically simulated environment. STATEMENT OF SIGNIFICANCE: Biodegradable metallic materials with resorbable degradation products have a high potential to be used for temporary implants such as screws, pins, staples, etc. They can eliminate the need for implant retrieval surgery after the damaged tissue is healed, and result in reduced patient suffering besides lowered hospitalization costs. Pure iron is biodegradable and is an essential nutrient in human body; however, its application as biomedical implant is highly restricted by its slow degradation rate in physiological environment. We applied a scalable surface treatment able to induce grain refinement and increase surface roughness. This treatment enhances mechanical performance of pure iron and accelerates its degradation rate, paving the way for its broader applications for biomedical implants
Impact of shot peening on corrosion performance of AZ31 magnesium alloy coated by PEO: Comparison with conventional surface pre-treatments
No full textThis paper deals with the evaluation of the influence of selected pre-treatments, namely shot peening, polishing and grinding, used prior to plasma electrolytic oxidation (PEO) on the corrosion characteristics of AZ31 magnesium alloy in solution of 0.1 M NaCl. Additionally, selected combinations of pre-treatment and PEO coating were optimized in terms of the PEO preparation time. Corrosion characteristics of prepared surfaces were determined by the electrochemical impedance spectroscopy (EIS) during 168 h of exposure at the laboratory temperature followed by the equivalent circuit analysis of measured Nyquist diagrams. Localised corrosion events of selected combinations of pre-treatment and PEO coating were observed by local electrochemical impedance spectroscopy (LEIM) in 1 mM NaCl supplied by the potentiodynamic polarization tests. The obtained results showed that despite the negative impact of shot peening on the electrochemical reactivity of AZ31 alloy, this technique significantly enhanced corrosion stability of the subsequently formed PEO coating
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
- …
