596 research outputs found
Wear performance of surface hardened PM steel from pre-alloyed powder
No full textPowder metallurgy (PM) processing of steels typically results in a material characterized by residual porosity reducing the mechanical strength of the material. That is why mechanical components produced from PM steels for high demanding applications often require a surface hardening in order to improve both the fatigue and the wear resistance. Among the surface treatments, gas nitriding assures economic advantages but the presence of interconnected porosity also makes the core structure involved by the diffusional phenomena. In this paper gas nitriding is proposed in combination with shot peening, as a surface densification technique, to improve the wear performances of PM components from prealloyed powder. 40mm diameter, 9.85mm thickness disks were pressed at 7.0g/cm3 density from a pre-alloyed powder (1.5% Cr, 0.5% Mo), with 0.8% graphite. The disks were sintered at 1120°C, 30min, in N2-H2 (90-10) atmosphere in an industrial equipment. Four conditions of the disks were examined: as-sintered, sintered and gas nitrided, sintered and shot-peened, sintered-shot peened-gas nitrided. The disks were characterized by experimental tests: dimensional variations, macro and microhardness profiles, LOM observations, surface texture analysis, residual stress analysis by X-Ray technique and pin on disk wear tests. The results of the wear tests were fulfilled with observations by SEM and new interesting interpretations of the involved mechanisms were proposed by the application of the energetic approach and non-standard wear tests
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AI and Administrative Values
No full textDavid Freeman Engstrom (Stanford Law), moderator ; Sofia Ranchordas (Groningen/LUISS/Yale ISP), Ifeoma Ajunwa (U. of North Carolina Law), Kristin Johnson (Emory Law), and Thibault Schrepel (VU Amsterdam/Stanford Law), panelists
AI and Administrative Values
No full textDavid Freeman Engstrom (Stanford Law), moderator ; Sofia Ranchordas (Groningen/LUISS/Yale ISP), Ifeoma Ajunwa (U. of North Carolina Law), Kristin Johnson (Emory Law), and Thibault Schrepel (VU Amsterdam/Stanford Law), panelists
On the measurement of formaldehyde release from low-emission wood-based panels using the perforator method
No full textIn Europe, the perforator method (EN 120) is the mostly used laboratory method of the wood-based panel industry. Usually, the measured perforator value depends on the moisture content of the boards. According to DIBt-100, the measured perforator values are corrected to a common moisture content (MC) of 6.5% using an established equation proposed by Jann and Deppe (1990). The correction factor of Jann and Deppe (1990) is based on the assumption that particle- and fibreboards change their perforator values to the same extent regardless whether increasing or decreasing the moisture content in the range of 3 a parts per thousand currency sign u a parts per thousand currency sign 9%. Application of this correction factor to particle- and fibreboards of higher moisture content than 6.5% can lead to biased corrected results in favour of low emission. The corrected values can also lead to paradoxical relation between the perforator values and emission in the low-emission region
Influence of molar ratio in aminoplastic resins on the dependence of the measured perforator values on the moisture content of wood-based panels
No full textThe correction factor developed by Jann and Deppe (1990) to adjust the measured perforator values of particleboards and fibreboards measured at different moisture contents in the range of 3% a parts per thousand currency sign u a parts per thousand currency sign 9% to the level at 6.5% moisture content has two main deficiencies. It takes no account of the influence of the molar ratio of the resins used, which seems to remarkably impact the relationship between the moisture content and the measured perforator values. Moreover, research work revealed that the correction factor to be applied also depends on the moisture content, at which the perforator value was measured, according to an inversely proportional correlation. Besides, the correction factor according to Jann-Deppe leaves this fact unconsidered
Procedural generation of challenges for personalized gait rehabilitation
No full textConventional gait rehabilitation methods have the risk of alienating the patient due to their monotonous nature, thus negatively impacting the effectiveness of gait training. Modern technologies can help provide patients with better support, safety and immersive experience during training. However, physiotherapists cannot be required to master those technologies, nor to spend much time designing a more varied and engaging treatment for each patient. In this paper, we argue that adaptive gamified gait rehabilitation based on procedural content generation (PCG) can effectively support physiotherapists in achieving such customized outcomes. We propose a generic adaptation scheme to steer the generation of movement challenge levels based on player modeling and therapists' intervention. Our approach features two difficulty adjustment strategies: parameter progression schemes and integration of multiple therapy goals. These strategies are applicable to the personalization of a wide range of gait rehabilitation goals. We implemented this approach in a standalone prototype for supporting gait training with the RYSEN system, a three-dimensional overground body weight support system. From our assessment with physiotherapists, we conclude that our PCG-based adaptive method effectively assists therapists in (i) offering a broad diversity in gait exercises to a wide group of patients, and (ii) dynamically tailoring challenge levels for a variety of gait tasks. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Computer Graphics and Visualisatio
Studies in Creative Collaborative Models and Paradigms: Investigating and Constructing Environments for Audience Interaction and Participation
No full textFor four years, intermedial artists Bethany Engstrom, Richard Corey, and John Bell have collaborated to produce immersive performances as The Core 5 Incident. This dissertation is a tripartite self-examination of the working methods they have developed to help address the specific creative, organizational, and personal challenges involved in artistic collaborations. The methods they describe are then applied to teaching a series of creative collaboration classes within a Master of Fine Arts program, with the resulting techniques further refined and contextualized for pedagogical use.
Using a version of Grounded Theory techniques that they have modified for self-study, the three authors identify several properties of collaborations that influence the effectiveness and appropriateness of different collaboration styles for creative work. The collaboration styles themselves are classified based on the balance between group will and personal creative agency and the degree to which the work generated by the group can be clearly broken back down into recognizable individual contributions. The strengths and weaknesses of each style are described, and it is concluded that a hybrid style dubbed emergent collaboration best fits The Core 5 Incident\u27s working method. The authors then review their own history to classify the significant concerns within a creative collaboration and the ways in which The Core 5 Incident handles those concerns that make emergent collaboration appropriate for their group.
Having developed a framework for examining creative collaborations, the authors then apply that framework to examining four iterations of a collaboration class in a Master of Fine Arts program-two taught by the authors, and two taught by other faculty. They conclude that, once extended to include topics specific to the classroom, the concerns they have described provide appropriate facets for examining contributing factors to the successes and failures within each of the classes. Based on these observations, they provide a number of suggestions and a recommended syllabus to use for teaching large-scale intermedial collaborations at the graduate level. Finally, the results of the study are contextualized by the lead author into her area of expertise, the construction of environments designed for audience interaction
Mark Shapley
No full textMark Shapley with research core from Spring Lake. Mark was a graduate student of Dan Engstrom at the University of Minnesota and the senior author of our Waubay paper published in the Holocen
[OP.7C.09] COFFEE, SMOKING HABITS AND BLOOD PRESSURE IN THE LIGHT OF A SINGLE NUCLEOTIDE POLIMORPHYSM OF CYP1A1/1A2 GENE
No full textOBJECTIVE: Between genetic variants pinpointed in genome wide association study there is the rs1378942 near the CYP1A1/CYP1A2 locus. Coffee consumption has been associated with blood pressure (BP) but with sometimes contrasting evidences. A part of BP-coffee relationship could be mediated by genetic mechanisms: that is single nucleotide polymorphisms (SNPs) nearby the CYP1A2 gene, which metabolize caffeine, could influence BP. Indeed, smoking habit induces the expression of the CYP1A2 enzyme whereas coffee consumption itself could increase CYP1A2 activity. The aim of the present study was to explore if coffee consumption and/or smoking habit may affect BP and BP change over time (delta-BP), considering the rs1378942A > C polimorphysm. DESIGN AND METHOD: Coffee intake was collected by a modified diet history method and the rs1378942 was genotyped by Taqman in > 28,000 participant of the Malmo Diet and Cancer (MDC). We performed a replication in 3381 participants that were rescreened after a period (13-20 years) of follow-up (MDC-FU) and in the Malmo Preventive Project (MPP; n > 17,000). RESULTS: In MDC, both systolic and diastolic BP were positively associated with the rs1378942A > C, suggesting that carrying the C variant could increase BP (for SBP beta = 0.397 ± 0.185, p = 0.031; for DBP beta = 0.220 ± 0.100, p = 0.028). Coffee consumption as well as smoking were negatively associated with both SBP and DBP (p C (pinteraction C and smoking (pinteraction < 0.05; data on coffe consumption not available). CONCLUSIONS: This study demonstrates that the effect of some genetic loci on BP could be highly influenced by voluptuary habits. In particular, coffee and smoke could influence the effect of the CYP1A1/CYP1A2 locus probably due to the metabolic action of the CYP1A2
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