677 research outputs found
Wear resistant multilayer nanocomposite WC1−x/C coating on Ti–6Al–4V titanium alloy
No full textA significant improvement of tribological properties on Ti–6Al–4V has been achieved by developed in this study multilayer treatment method for the titanium alloys. This treatment consists of an intermediate 2 μm thick TiCxNy layer which has been deposited by the reactive arc evaporation onto a diffusion hardened material with interstitial O or N atoms by glow discharge plasma in the atmosphere of Ar+O2 or Ar+N2. Subsequently, an external 0.3 μm thin nanocomposite carbon-based WC1−x/C coating has been deposited by a reactive magnetron sputtering of graphite and tungsten targets. The morphology, microstructure, chemical and phase compositions of the substrate material after treatment and coating deposition have been investigated with use of AFM, SEM, EDX, XRD, 3D profilometry and followed by tribological investigation of wear and friction analysis. An increase of hardness in the diffusion treated near-surface zone of the Ti–6Al–4V substrate has been achieved. In addition, a good adhesion between the intermediate gradient TiCxNy coating and the Ti–6Al–4V substrate as well as with the external nanocomposite coating has been obtained. Significant increase in wear resistance of up to 94% when compared to uncoated Ti–6Al–4V was reported. The proposed multilayer system deposited on the Ti–6Al–4V substrate is a promising method to significantly increase wear resistance of titanium alloys
Comparison of shot peening and nitriding surface treatments under complex fretting loadings
No full textConsidered as a plague for numerous industrial assemblies, fretting associated with small oscillatory displacements is encountered in all quasi-static contacts submitted to vibrations. According to the sliding conditions, fretting cracks and/or fretting wear can be observed in the contact area. On the other hand an important development has been achieved in the domain of surface engineering during the past three decades and numerous new surface treatments and coatings are now available. Therefore there is a critical challenge to evaluate the usefulness of these new treatments and/or coatings against fretting damage. To achieve this objective, a fast fretting methodology has been developed. It consists in quantifying the palliative friction, cracking and wear responses through a very small number of fretting tests. With use of defined quantitative variables, a normalized polar fretting damage chart approach is introduced. Finally, to evaluate the performance of the assemblies after these protective surface treatments under complex fretting loadings, an original sequence of partial slip and gross slip sliding procedure has been applied. It has been demonstrated that performing of a very short sequence of gross slip fretting cycles can critically decrease the resistance of the treated surfaces against cracking failures activated under subsequent partial slip loadings
Musika eta Mintzairaren Sorrera
No full textEn el presente artículo el autor se refiere a la relación evolutiva entre música y lenguaje y a la naturaleza de ambas habilidades, exponiendo distintas teorías del pasado y actuales en torno a la cuestión. El articulista defiende con B.G. Levman que tanto el lenguaje como la música nacieron de una misma capacidad primitiva y considera aquel lenguaje fundamentalmente como música. Da cuenta de los pros y los contras de las hipótesis que adelanta. En este sentido, expone las conductas de diversos pueblos y razas y diferentes animales, componiendo un tratamiento particularmente completo del tema con análisis efectuados desde diversas disciplinas: etnomusicología, etología, antropología, psicología, acústica.Artikulu honetan autoreak musika eta mintzairaren harreman ebolutiboaz nahiz bi gaitasunon izaeraz dihardu, horren gainean diren eta izan diren teoria ezberdinak azalduz. B.G. Levman artikulugileak berak bai mintzaira eta bai musika antzin-gaitasun beretik sortu zirela defenditzen du, eta orduko mintzaira hura funtsean musikazkotzat jotzen du. Agertzen dituen hipotesien aldekotasun eta kontrakotasunak ematen ditu. Horretarako mundu zabaleko hainbat herri eta animalia arrazen jokamoldeak ekartzen ditu paperera, eta etnomusikologia, etologia, antropologia, psikologia, akustikaren ikuspegitik aztertzen, gaiaren tratamendu bereziki borobila eta osatua eginez.Dans cet article, l'auteur parle de la relation évolutive entre musique et langage et la nature de ces deux talents, en exposant différentes théories du passé et du présent concernant cette question. L'auteur et B.G. Levman défendent la théorie qui soutient que le langage et la musique naquirent d'une même capacité primitive et considèrent ce langage fondamentalement comme de la musique. Il explique le pour et le contre de l'hypothèse qu'il avance. Dans ce sens, il expose les conduites de divers peuples et races et de différents animaux, en traitant le sujet d'une façon particulièrement complète, avec des analyses sur diverses disciplines: ethno-musicologie, éthologie, anthropologie, psychologie, acoustic.In the present article the author makes reference to the evolutionary relationship between music and language and to the nature of both skills, exposing different theories in the past and present in connection with this issue. The author maintains, together with B.G.Levman, that both language and music were born out of the same primitive capacity and considers that language is, fundamentally, music. He also reports on the pros and cons of the hypothesis he advances. In this sense, he describes the conduct of various peoples and races and of various animals, constructing a particularly complete treatment of the topic with analysis carried out from various disciplines: ethnomusicology, ethology, anthropology and psychology
B.G. Wood
No full textMade available by the Northern Territory Library via the Publications (Legal Deposit) Act 2004 (NT).Date:1985-03Acknowledgements:
The author acknowledges the field and office assistance of Ian Hall and
Jon Burgess during the preparation and completion of this project
Beginselen en voorbeelden van regelgeving en beleid ten aanzien van de opsporing en winning van aardolie en aardgas
No full textCivil Engineering and Geoscience
Raadgevende ingenieurs en groot-onderhoud; Uitbesteding van projektmanagement in de sociale huursector
No full textArchitectur
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