1,720,962 research outputs found
Dataset for 'A novel surface texture shape for directional friction control'
No full textAll data supporting this study were collected from the PhD Project: The Use of Surface Texturing for Friction Control. The influence of anisotropically shaped textures on the behaviour of sliding friction and sensitivity to sliding direction was evaluated through experimental methods, and performance of textured surfaces was carefully compared with non-textured surfaces.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 644971.</span
Tribology testing of ultrafine-grained Ti processed by high pressure torsion with subsequent coating
No full textA grade 2 pure Ti was processed by high-pressure torsion (HPT) under 3.0 GPa for 10 revolutions to achieve an improved strength. Wear tests revealed that HPT only slightly improved the wear resistance of pure Ti. Subsequently, a TiN coating with a thickness of 2.5 ?m was deposited on different Ti substrates to improve the wear resistance. Both indentation and scratch testing demonstrated a much improved load-bearing capacity when ultrafine-grained Ti was chosen as the substrate compared with coarse-grained Ti. All results indicate that pure Ti processed by HPT, when combined with a subsequent coating, represents a good candidate material for bio-implant applications
The friction reducing effect of square-shaped surface textures under lubricated line-contacts - an experimental study
No full textSurface texturing has been shown to be an effective modification approach for improving tribological performance. This study examined the friction reduction effect generated by square dimples of different sizes and geometries. Dimples were fabricated on the surface of ASP2023 steel plates using femtosecond laser-assisted surface texturing techniques, and reciprocating sliding line contact tests were carried out on a Plint TE77 tribometer using a smooth 52100 bearing steel roller and textured ASP2023 steel plates. The tribological characterization of the friction properties indicated that the textured samples had significantly lowered the friction coefficient in both boundary (15% improvement) and mixed lubrication regimes (13% improvement). Moreover, the high data sampling rate results indicated that the dimples work as lubricant reservoirs in the boundary lubrication regim
Effect of grain size on the micro-tribological behavior of pure titanium processed by high-pressure torsion
No full textThe micro-wear behavior of commercial pure Ti was investigated before and after processing by high pressure torsion (HPT) to provide comparisons over a range of grain sizes. The HPT-processed Ti had an average grain size of ?130 nm while the as-received and HPT plus annealed samples had grain sizes of ?8.6 m and ?607 nm, respectively. The results show all Ti samples have a similar dynamic coef?cient of friction but different wear mechanisms. Wear of the coarse grained (CG) Ti showed extensive plastic deformation and wedge formation which produced large wear debris whereas wear of the ultra-?ne grained (UFG) Ti was dominated by abrasive wear mechanisms and produced small wear debris. In addition, the UFG Ti showed a more homogenous wear grooving and a lower wear rate than CG Ti which suggests that UFG Ti is more suitable for wear applications.<br/
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
The use of anisotropic texturing for control of directional friction
No full textThis paper presents a study on the influence of anisotropically shaped texture arrays on friction behaviour of an oil lubricated sliding contact, especially on directional friction control based on the diverging and converging characteristics of the textures. Experiments have been conducted on a TE77 reciprocatingcylinder-on-plate test rig, where steel rollers were used to slide against steel plate samples with or without textures. A mineral base oil was used to lubricate the contacts. Three geometries of dimples were designed and laser textured on the steel plate samples with varied 3-dimensional features, including Square Flat (SF), Square slope (SS) and Triangular Flat (TF) shapes representing the shape in x-y (top view) and x-z (side view) planes respectively. These shapes were chosen to vary the converging and diverging properties of the lubricated contacts depending on the sliding direction. Relatively large dimple sizes (side length ~500 and depth ~10 ) have been used in this study to enable observation of the effect and easy control of the texturing process. The texture density has been kept at 10% as most literature suggested. The large dimple sizes resulted that the dimples were not be fully covered by the contact area, i.e. the dimple sides were bigger than the Hertzian contact width of the roller-flat contacts. This has eliminated the ‘lift’ or ‘load bearing’ effect discussed in most papers thus focuses on other effects investigated in this study. The results show that beneficial effects of theanisotropic textures present in all lubrication regimes including the boundary, mixed and hydrodynamic lubrications, especially under prevailing boundary lubrication conditions. Using high sampling rate for the friction data during the tests, it was able to study local friction effect due to individual dimple array especially at their leading and trailing edges. The results show that a local friction reduction is observed at the leading while an increase at the trailing edge. Overall directional friction effect of the anisotropic textures has been observed that the converging shape in both y-z plane and the x-y plane reduces friction. Furthermore, it was found that the triangular shape dimples have a greater local frictional response at each dimple array, while the sloped bottomsquare dimples have a more significant overall directional fricition effect
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