Tribological properties and wear mechanisms of DC pulse plasma nitrided austenitic stainless steel in dry reciprocating sliding tests

Expanded austenite (Gamma-N), or S-phase, is a special phase of low-temperature nitrided austenite containing highly super-saturated nitrogen in the form of heterogeneous Cr-N nano-clusters. A nitrided layer of singe phase N is known to provide austenitic stainless steel with combined high hardness, good wear resistance and superior corrosion resistance. This paper reports recent experiments on a comparative study of the sliding wear properties and wear mechanisms of nitrided austenite stainless steel AISI 316, with a special attention paid on worn surface structural evolutions induced by frictional heating and sliding deformation. The samples were prepared by DC pulsed plasma nitriding treatments of various time at a fixed power. Knoop micro-indentation has revealed hardening behaviour of the nitrided samples. The reciprocating ball-on-disc sliding wear and friction properties were investigated at ambient environment conditions using an alumina counterpart ball. The worn surfaces have been analysed by XRD,FEG-SEM and EDX to show wear induced changes in the crystalline characteristics and the wear mechanisms of tribo-oxidation, cracking, abrasive wear and ploughing deformation. Moreover, longitudinal cross-sectional foils of the worn samples have been prepared and analysed using TEM, to investigate the wear induced structural changes, including tribofilm formation, plastic deformation and delamination in depths of nano-scale

On the nitrogen-induced lattice expansion of a non-stainless austenitic steel, Invar 36®, under triode plasma nitriding

Chromium, as a strong nitride-forming element, is widely regarded to be an “essential” ingredient for the formation of a nitrogen-expanded lattice in thermochemical nitrogen diffusion treatments of austenitic (stainless) steels. In this article, a proprietary “chrome-free” austenitic iron-nickel alloy, Invar® 36 (Fe-36Ni, in wt pct), is characterized after triode plasma nitriding (TPN) treatments at 400 °C to 450 °C and compared with a “stainless” austenitic counterpart RA 330® (Fe-19Cr-35Ni, in wt pct) treated under equivalent nitriding conditions. Cr does indeed appear to play a pivotal role in colossal nitrogen supersaturation (and hence anisotropic lattice expansion and superior surface hardening) of austenitic steel under low-temperature (≤ 450 °C) nitrogen diffusion. Nevertheless, this work reveals that nitrogen-induced lattice expansion occurs below the nitride-containing surface layer in Invar 36 alloy after TPN treatment, implying that Cr is not a necessity for the nitrogen-interstitial induced lattice expansion phenomenon to occur, also suggesting another type of γN

A cross-disciplinary curriculum of art and writing: Using the sensory properties to teach printmaking, book making, and creative (memoir) writing

This study examines a cross-disciplinary curriculum that uses guided imagery and writing warm-ups to enhance student awareness of sensory properties in the teaching of printmaking, book making and memoir writing. I questioned whether implementation of such a course could: (1) increase student motivation? (2) show improvement in student writing? (3) show student comprehension and application of basic printmaking and book making techniques? (4) show evidence of experimentation in student artwork that results from an awareness of the sensory properties? The curriculum was taught to two courses of middle school students during the University of Arizona's SEEK (Summer Education Enrichment for Kids) program. Each course was two weeks' duration for two hours a day. Quantitative and qualitative results indicate an improvement in student writing and a comprehension and application of printmaking and book making techniques, in addition to experimentation in art as a result of awareness of the sensory properties. Evidence also suggests that both subjects enhance one another when taught together

Electron Diffraction Reinvestigation of CdCr2Se4 and ZnCr2-xVxSe4 Spinel Structures

Crystal structure of two spinel single crystals CdCr2Se4 and ZnCr2-xVxSe4 have been reinvestigated using automated electron diffraction tomography method with beam precession. 3D reciprocal space have been reconstructed base on recorded tilt series. For both samples crystal structure was refined and the cubic symmetry with space group Fd 3̄m was confirmed. No additional electron potential has been located beside occupied atom sites. © (2013) Trans Tech Publications, Switzerland

L’intérêt des techniques mobile-in-store : le rôle spécifique de l’orientation d’achat

International audienceInterest toward mobile-in-store techniques: taking into account shopping orientationsRetailers adopt mobile strategies in order to enrich the customer experience at the point of sale. Mobile-in-storetechniques are built on various technologies and deliver different benefits to customers. They deliver utilitarian,hedonic and symbolic benefits, but can also be regarded as intrusive. That raises questions on consumers’ interestin them. A quantitative survey was administered online to mobile users to investigate the degree of interest foreach technique. The results highlight the moderating role of shopping orientations: when the mobile-in-storetechnique is congruent (versus incongruent) with the shopper profile, it increases (versus decreases) the interestin it. This research leads to think retailers should offer a bunch of techniques adapted to each customer profile.L’enrichissement de l’expérience client est au cœur de la digitalisation des points de vente. Les techniquesmobile-in-store, si elles délivrent des bénéfices utilitaires, hédoniques et symboliques, peuvent également êtreconsidérées comme intrusives, ce qui conduit à s’interroger sur l’intérêt que les consommateurs leur portent. Unquestionnaire administré en ligne met en évidence, au-delà des effets constants des variables psychographiques,le rôle modérateur des orientations d’achat : une technique cohérente (vs. incohérente) avec l’orientation duclient augmente (vs. réduit) l’intérêt qu’il lui porte. Ce résultat conduit à proposer des « bouquets » de techniquess’adaptant à chaque profil de client

L’intérêt des techniques mobile-in-store : le rôle spécifique de l’orientation d’achat

International audienceRetailers adopt mobile strategies in order to enrich the customer experience at the point of sale. Mobile-in-store techniques are built on various technologies and deliver different benefits to customers. A quantitative survey was administered to mobile users to investigate the degree of interest for each technique. The results highlight the moderating role of shopping orientations: when the mobile-in-store technique is congruent (versus incongruent) with the shopper profile, it increases (versus decreases) the interest in it. Therefore, retailers should offer a bunch of techniques adapted to each customer profile.L'enrichissement de l'expérience client est au cœur de la digitalisation des points de vente. Les techniques mobile-in-store, si elles délivrent des bénéfices utilitaires, hédoniques et symboliques, peuvent également être considérées comme intrusives, ce qui conduit à s’interroger sur l’intérêt que les consommateurs leur portent. Un questionnaire administré en ligne met en évidence, au-delà des effets constants des variables psychographiques, le rôle modérateur des orientations d’achat : une technique cohérente (vs. incohérente) avec l’orientation du client augmente (vs. réduit) l’intérêt qu’il lui porte. Ce résultat conduit à proposer des « bouquets » de techniques s’adaptant à chaque profil de client

L’intérêt des techniques mobile-in-store : le rôle spécifique de l’orientation d’achat

International audienceRetailers adopt mobile strategies in order to enrich the customer experience at the point of sale. Mobile-in-store techniques are built on various technologies and deliver different benefits to customers. A quantitative survey was administered to mobile users to investigate the degree of interest for each technique. The results highlight the moderating role of shopping orientations: when the mobile-in-store technique is congruent (versus incongruent) with the shopper profile, it increases (versus decreases) the interest in it. Therefore, retailers should offer a bunch of techniques adapted to each customer profile.L'enrichissement de l'expérience client est au cœur de la digitalisation des points de vente. Les techniques mobile-in-store, si elles délivrent des bénéfices utilitaires, hédoniques et symboliques, peuvent également être considérées comme intrusives, ce qui conduit à s’interroger sur l’intérêt que les consommateurs leur portent. Un questionnaire administré en ligne met en évidence, au-delà des effets constants des variables psychographiques, le rôle modérateur des orientations d’achat : une technique cohérente (vs. incohérente) avec l’orientation du client augmente (vs. réduit) l’intérêt qu’il lui porte. Ce résultat conduit à proposer des « bouquets » de techniques s’adaptant à chaque profil de client