686 research outputs found

    Concept for the cost prognosis in the industrialization of highly iteratively developed physical products

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    With the ongoing technological progress and increasing global competition, companies are facing a continuously changing market environment. Due to the volatility of the market, rapid product adjustments and shorter product life cycles are required. Changing customer requirements are rarely taken into account, leading to inventions that do not make the transition to innovations. Highly iterative product development poses a possibility to integrate the customer voice into the development process and thus shorten the time-to-market and enable companies to respond to changes in requirements. Within the scope of highly iterative product development methods, cost analysis remains one of the main challenges for companies. Since the scope of development is not known at the beginning of a project, neither development nor industrialization costs can be specified. This, however, is essential for product and process development to meet cost-related customer requirements and for forecasting the production and investment budgets. With existing methods, it is either possible to agree to a fixed development budget and target price or to enable the customer to make changes during development. The concept presented in this paper aims to counteract this challenge. Therefore, existing approaches are analyzed with regard to derived requirements for the transfer from highly iterative and integrated product and process development to agile cost analysis. Influencing factors on product and production process costs are identified based on findings from literature. By aligning the influencing factors and requirements, dependencies between target costs of a product and degrees of freedom of highly iterative product and production process development can be derived and used for the development of a framework for iterative cost analysis. In conclusion, a concept for an agile cost prognosis for the industrialization of highly iterative developed physical products is presented

    Data-based identification of knowledge transfer needs in global production networks

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    Manufacturing companies’ value chains are increasingly distributed globally, which presents companies with the challenge of coordinating complex production networks. In general, these production networks grew historically rather than having been continuously planned, leading to heterogeneous production structures with many tangible and intangible flows to be coordinated. Thereby, many authors claim that the knowledge flow is one of the most important flows and the source of competitive advantage. However, today’s managers face major challenges in transferring production knowledge, especially across globally distributed production sites. The first obstacle to a successful knowledge transfer is to identify what kind of knowledge should be transferred between whom and at what time. This process can take months of information collection and evaluation and is often too time-consuming and costly. Thus, this paper presents an approach to automatically identify at what point knowledge should be transferred. In order to achieve this, the company's raw data is being used to identify which employees work on similar production processes and how these processes perform. Therefore, production processes, which can be compared with each other, need to be formed, even though these processes may be performed at different production sites. Still, not every defined cluster of production processes necessarily requires the initiation of knowledge transfer since performing a knowledge transfer always entails considerable effort and some processes might already be aligned with each other. Consequently, in a next step it is analyzed how these comparable production processes differ from each other by taking into account their performances by means of feedback data. As a result, trigger points for knowledge transfer initiation can be determined

    Studies on the vascular cambium

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    The nature of the vascular cambium is discussed and the length of the elements in the secondary xylem related to the division and elongation cycles of the cambial fusiform initials. Particular attention is given to the activities of the storeyed cambium. The ontogeny of the storeyed cambium is described for Hoheria angustifolia Raoul. (Malvaceae). The transition from procambium to cambium was found to take place gradually, the meristem acquiring cambial characteristics over a number of internodes, some before and some after internodal elongation had ceased. The cambium is non storeyed at the commencement of secondary growth but later develops a storeyed pattern. Developmental changes in the cambium with radial growth were studied in Aeschynomene hispida Willd. (Papilionaceae). Repeated radial longitudinal divisions in the fusiform cambial initials in this plant produce a highly developed storeyed pattern with radial growth. The frequency of these divisions decreases with increasing distance from the stem centre. The mean length of the fusiform initials decreases slightly with radial growth. Variation in the size of the fusiform initials and vessel members was also investigated in Hoberia angustifolia. Mean length of the fusiform initials was found to remain constant with increasing distance from the stem centre but a slight decrease was observed with increasing height in the tree. Mean fusiform initial width showed an increase followed by a decrease with increasing height in the tree. The significance of these results is related to the division pattern in the storeyed cambium

    Evaluation of the non-linear properties of two computational models of the peripheral auditory system

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    The output responses of two computational models of the peripheral auditory system were investigated. The models used were the Carney model, described in Zilany et al. (2009) and the Seneff model, as described in Seneff 1988. Of particular interest is the exhibition of the ‘synchrony capture’ phenomenon. This occurs when the auditory nerve fibre preferentially fires in time sync with a single spectral component within a complex sound. The studies of Sinex et al. (2003) and Deng et al. (1987) were used for visual comparison to the modelled responses with regards to synchrony capture. Sinex et al. (2003) showed synchrony capture in the responses of auditory nerve fibres to components within a harmonic tone against increasing intensity. Deng et al. (1987) showed synchrony capture to a component over increasing relative intensity of that component within a harmonic tone. The results revealed that the Seneff model showed strong agreement to the recorded response sets presented in Sinex et al. (2003 and Deng et al. (1987). The Carney model showed strong agreement to the synchrony capture presented in Deng et al. (1987) but responses did not have strong agreement to synchrony capture presented in Sinex et al. (2003)

    Growth of Large-Area, Stress-Free, and Bulk-Like 3C-SiC (100) Using 3C-SiC-on-Si in Vapor Phase Growth

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    We report on the reproducible growth of two inch 3C-SiC crystals using the transfer of chemical vapor deposition (CVD)-grown (100) oriented epitaxial layers. Additional experiments, in which the diameter of the free-standing layers is increased, are presented, indicating the upscale potential of this process. The nucleation and growth of cubic silicon carbide is supported by XRD and Raman measurements. The rocking curve data yield a full-width-at-half-maximum (FWHM) between 138 to 140 arc sec for such grown material. Analysis of the inbuilt stress of the bulk-like material shows no indications of any residual stress

    Limitations during Vapor Phase Growth of Bulk (100) 3C-SiC Using 3C-SiC-on-SiC Seeding Stacks

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    The growth of 3C-SiC shows technological challenges, such as high supersaturation, a silicon-rich gas phase and a high vertical temperature gradient. We have developed a transfer method creating high-quality 3C-SiC-on-SiC (100) seeding stacks, suitable for use in sublimation “sandwich” epitaxy (SE). This work presents simulation data on the change of supersaturation and the temperature gradient between source and seed for the bulk growth. A series of growth runs on increased source to seed distances was characterized by XRD and Raman spectroscopy. Results show a decrease in quality in terms of single-crystallinity with a decrease in supersaturation. Morphology analysis of as-grown material indicates an increasing protrusion dimension with increasing thickness. This effect limits the achievable maximal thickness. Additional polytype inclusions were observed, which began to occur with low supersaturation (S ≤ 0.06) and prolonged growth (increase of carbon gas-species)

    An adhesive bonding approach by hydrogen silsesquioxane for silicon carbide-based LED applications

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    We report an adhesive bonding approach using hydrogen silsesquioxane (HSQ) for silicon carbide (SiC) samples. A hybrid light-emitting diode (LED) was successfully fabricated through bonding a near-ultraviolet (NUV) LED grown on a commercial 4H-SiC substrate to a free-standing boron-nitrogen co-doped fluorescent-SiC epi-layer. The bonding quality and the electrical performance of the hybrid LED device were characterized. Neither voids nor defects were observed which indicates a good bonding quality of the proposed HSQ approach. A strong warm white emission was successfully obtained from the hybrid LED through an electric current injection of 30 mA.Funding Agencies|Innovation Fund Denmark [4106-00018B]</p
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