1,818 research outputs found

    Design and evaluation of a virtual gearshift application

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    When a customer buys a new car, he or she wants it to address personal preferences with respect to its driving behavior. By utilizing virtual reality technology, a virtual prototyping environment (VPE) can be created in which the behavior of a vehicle or part of a vehicle can be evaluated and adjusted to match the driver's desires. This paper describes the design and the evaluation of a VPE for manually operated gearboxes. The test group considered the simulated "virtual" gearshift feel to be quite similar to the "real" gearshift feel of a test vehicle. By further developing this VPE, it should become possible to define gearshift feel by customer assessment through haptic simulation, after which the physical gearbox is designed in such a way that it matches the preferred shifting behavior

    Comparative analysis of Bacillus weihenstephanensis KBAB4 spores obtained at different temperatures

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    The impact of Bacillus weihenstephanensis KBAB4 sporulation temperature history was assessed on spore heat resistance, germination and outgrowth capacity at a temperature range from 7 to 30 °C. Sporulation rate and efficiency decreased at low temperature, as cells sporulated at 12, 20 and 30 °C with approximately 99% efficiency, whereas at 7 °C and 10 °C, a maximum 15% of sporulation was reached. Spores formed at 30 °C showed the highest wet heat resistance at 95 °C, with spores formed at 7 and 10 °C displaying only survival of 15 min exposure at 70 °C, indicating their low level heat resistance. RT-PCR analysis revealed expression of sporulation sigma factor sigG, and germinant receptor operons gerI, gerK, gerL, gerR, gerS, and (plasmid-located) gerS2 to be activated in all sporulation conditions tested. Subsequent germination assays revealed a combination of inosine and L-Alanine to be very efficient, triggering over 99% of the spores to germinate, with spores obtained at 30 °C showing the highest germination rates (99%). Notably, spores obtained at 12, 20 and 30 °C, germinated at all tested temperatures, showing > 70% spore germination even at temperatures as low as 5 °C. Less than 5% of spores obtained at 7 and 10 °C showed a germination response. Furthermore, spores produced at 12, 20 and 30 °C showed similar outgrowth effiency at these temperatures, indicating that low temperature sporulation history does not improve low temperature outgrowth performance. Insights obtained in sporulation and germination behaviour of B. weihenstephanensis KBAB4, in combination with the availability of its genome sequence, may contribute to our understanding of the behaviour of psychrotolerant spoilage and pathogenic Bacill

    Understanding design for dynamic and Diverse Use Situations

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    The design research community acknowledges that usability and user experience are largely influenced by user characteristics, goals and contexts of use. For industrially manufactured products, these use situations are often dynamic and diverse. However, little guidance can be found in literature on the incorporation of dynamic and diverse use situations (DDUS) into the design process. This paper explores this issue by means of an analysis of user centred design literature and an empirical study of design for DDUS in design practice. We retrospectively studied three projects in which a product with DDUS was designed. Based on this study, we identified different effective strategies executed by design practitioners to analyse DDUS. We also observed difficulties in designing for DDUS. These difficulties include the identification of relevant aspects within this broad spectrum of use situations and sharing knowledge of product use between team members. We conclude that there is a need for guidance in the creation of flexible frames of reference of product use that evolve with solutions in the design process, particularly for design projects that cannot rely on the reuse of such a frame of reference from similar previous projects. © 2014 van der Bijl-Brouwer & van der Voort

    H-alpha features with hot onsets. II. A contrail fibril

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    The solar chromosphere observed in H-alpha consists mostly of narrow fibrils. The longest typically originate in network or plage and arch far over adjacent internetwork. We use data from multiple telescopes to analyze one well-observed example in a quiet area. It resulted from the earlier passage of an accelerating disturbance in which the gas was heated to high temperature as in the spicule-II phenomenon. After this passage a dark H-Halpha fibril appeared as a contrail. We use Saha-Boltzmann extinction estimation to gauge the onset and subsequent visibilities in various diagnostics and conclude that such H-alpha fibrils can indeed be contrail phenomena, not indicative of the thermodynamic and magnetic environment when they are observed but of more dynamic happenings before. They do not connect across internetwork cells but represent launch tracks of heating events and chart magnetic field during launch, not at present.Comment: Accepted for Astronomy & Astrophysic

    Germinant receptor diversity and germination responses of four strains of the Bacillus cereus group

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    Four strains of the Bacillus cereus group were compared for their germinant receptor composition and spore germination capacity. Phylogenetic analysis of the germinant receptor encoding operons of the enterotoxic strains B. cereus ATCC 14579 and ATCC 10987, the emetic strain AH187, and the psychrotolerant strain Bacillus weihenstephanensis KBAB4, indicated a core group of five germinant receptor operons to be present in the four strains, with each strain containing one to three additional receptors. Using quantitative PCR, induction of expression during sporulation was confirmed for all identified germinant receptor operons in these strains. Despite the large overlap in receptors, diversity in amino acid-induced germination capacity was observed, with six out of 20 amino acids, serving as germinants for spores of all four strains. Each strain showed unique features: efficient germination of strain KBAB4 spores required non-inducing amounts of inosine as the co-germinant, strain ATCC 10987 spores germinated only efficiently after heat activation. Furthermore, strain ATCC 14579 and AH187 spores germinated without heat activation or inosine, with strain ATCC 14579 spores being triggered by all amino acids except phenylalanine and strain AH187 spores being specifically triggered efficiently only by phenylalanine. Analysis of all germination data did not reveal strict linkages between specific germinants and germinant receptors. Finally, the diversity in nutrient-induced germination capacity was also reflected in the diverse germination responses of heat-activated spores of the four B. cereus strains in food matrices, such as milk, rice water and meat bouillon, indicating that amino acid composition and/or availability of inosine are important germination determinants in foods. Keywords: Ger operon; Food preservation; B. weihenstephanensis; Sporulatio

    Thinking and Exploring Use Situations

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    Within design teams, knowledge of the variety of situations in which products are used remains often unshared. Furthermore these 'dynamic and diverse use situations' are not always applied consistently to contextualize use evaluations. This paper describes the development of guidelines to deal with these issues in the design process. The initial guidleines were aimed at generating and applying an evolving explicit frame of reference of product use that could be used to set up use evaluations, to share knowledge of product use and to inspire solution generation. an application of the guidelines to a carrier bike by four student teams showed the added value of using the frame of reference in setting up use evaluations, the value of explorative activities to create explicit frame of reference, and unexpected benefits of the additionally created mindset

    Designing on the road; Exploring the who, where and why of individual mobility devices

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    The aim of this study is to support designers in dealing with the variety of situations in which product are used, so-called dynamic and diverse use situations (DDUS). Dealing with varying use situations in the design process is difficult because it is hard to predict the situations in which a product will be used, to anticipate what will happen when the product encounters those situations and to generate solutions for conflicting requirements. A retrospective case study of three design projects in practice furthermore showed that knowledge of DDUS often remains implicit and is not shared between members of a product development team. We therefore developed a set of guidelines to support designers and design teams when dealing with DDUS in the design process. The basic principle of the guidelines is that existing design activities are used to create and apply an explicit 'frame of reference of product use' which makes DDUS and their relation to use issues explicit. In this paper we explain these guidelines and show its application to the design of an individual mobility device
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