81 research outputs found
The fragility of human-centred design
No full textIn human-centred design (HCD), researchers and designers develop products in cooperation with the potential users of these products. They attempt to give users a voice or a role in their projects, with the intention of developing products that match users' needs and preferences. This approach is especially interesting in the information and communication technology (ICT) industry, in which many innovations are driven by development of technologies. The author works in HCD projects in the ICT industry and studied one particular project as a participant observer. In this project, two telecom applications were designed together with and for two groups of users: police officers and people who provide informal care. The resulting case studies are interpreted, drawing from the fields of design studies and science and technology studies, and using texts of the philosophers Levinas and Derrida. HCD is presented as a process that happens between people and as a process with ethical qualities. The case studies demonstrate that HCD is a worthwhile approach. They also show the difficulties of cooperating with users and of multi-disciplinary team-work. HCD practitioners attempt to be open towards others, but they also tend to move towards closure and towards the self. The author suggests reflexive practice as a way for practitioners to be more aware of and to articulate these tendencies. This is intended to help them to better align their practices with what HCD can be about: a process of learning and creating together.Industrial Design Engineerin
Verfverwijdering door inslagen van individuele gritstraaldeeltjes
No full textGritstralen is een verfverwijderingstechniek, die gebaseerd is op de inslagen van kleine, hoekige deeltjes op een verfoppervlak. Om een efficiënter gebruik van straalmiddel mogelijk te maken, moet fundamenteel onderzoek worden gedaan naar het verfverwijderingsmechanisme. In deze studie is een beter inzicht in het proces verkregen door het effect van individuele deeltjesinslagen op een verfoppervlak te analyseren. In de experimentele opzet is geprobeerd zo dicht mogelijk op de praktijk van gritstralen aan te sluiten. Individuele gritdeeltjes zijn in de meetopstelling onder verschillende hoeken met snelheden tot 100 m/s afgeschoten op proefplaten met een epoxycoating, waarvan hardheid en elasticiteit zijn gevarieerd en experimenteel zijn vastgesteld. Door naast gritdeeltjes ook modeldeeltjes te gebruiken is geprobeerd de reproduceerbaarheid van de inslagen te vergroten. De ontstane inslagkraters zijn onderzocht met behulp van optische triangulatie. Deze meetmethode beeldt een dwarsdoorsnedeprofiel van een krater vergroot af op een scherm. Uit microscoopfoto's van de inslagkraters en de informatie uit de triangulatiebeelden zijn kratervolumes berekend. Vergelijking van de onderzoeksresultaten met literatuur over erosie duidt op een ductiel gedrag van de gebruikte verflaag. De experimenteel gevonden snelheidsafhankelijkheid van het kratervolume bij deeltjesinslagen is globaal in overeenstemming met de derdemachtsafliankelijkheid, die gevonden wordt in een dimensieanalyse over de voor verfverwijdering belangrijke parameters.Kramers Laboratorium voor Fysische TechnologieApplied Science
Laser Doppler metingen van deeltjessnelheden in gritstralen
No full textGritstralen is een veel gebruikte verfverwijderingstechniek die gebruik maakt van kleine, kantige deeltjes die versneld worden door perslucht. De noodzaak om efficiënter om te gaan met de hierbij gebruikte straalmiddelen wordt steeds sterker vanwege stringentere milieueisen en sterke concurrentie van de lage lonen landen. Om het gritstraalproces efficiënter te maken is nader onderzoek van het gritstralen noodzakelijk. Dit afstudeeronderzoek richt zich op de vrije, turbulente lucht-deeltjes jet. De gemiddelde snelheden van de deeltjes en de verbreding van de jet stroomafwaarts zijn onderzocht met behulp van twee-dimensionale Laser Doppler Anemometrie. De LDA-metingen zijn bijzonder omdat er gemeten is met relatief grote deeltjes en bij zeer hoge snelheden. Voor de bepaling van de verbreding van de jet is de data rate als maat genomen. Er is geprobeerd de meetopstelling zo dicht mogelijk bij de praktijk te laten aansluiten door een industriële gritketel te gebruiken. De metingen zijn uitgevoerd met een 6 mm venturi nozzle en twee soorten staalgrit met gemiddelde deeltjesdiameters van 210 µm en 350 µm bij nozzledrukken tot 5.6 bar met beladingsgraden van 3.5 tot 8 kg grit/kg lucht. Metingen van axiale en radiale snelheden zijn gedaan tot 80 cm achter de nozzle. De gemiddelde axiale snelheid blijkt toe te nemen tot circa 10 cm achter de nozzle en daalt vervolgens voor grotere afstanden. De breedte van de jet verandert vrijwel lineair met de afstand tot de nozzle. De nozzledruk heeft geen meetbare invloed op de breedte van de jet. Bij grotere deeltjesdiameter is de verbreding van de jet groter.Kramers Laboratorium voor Fysische TechnologieApplied Science
Uma metodologia de calculo para a simulação de mancais radiais submetidos a carregamento dinamico
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoA teoria da lubrificação hidrodinâmica, baseada na equação de reynolds, é utilizada na determinação das características operacionais de mancais radiais submetidos a carregamentos dinâmicos. A equação de reynolds, na sua forma bidimensional, é integrada numericamente através dos volumes finitos. A cavitação do filme de óleo é considerada, o que torna o modelo matemático um problema de fronteira livre, contornado pelo uso de malhas não-ortogonais adaptadas a fronteira. O comportamento dinâmico do mancal representado pela trajetória do eixo, é obtido através da resolução de um sistema de equações diferenciais, originárias do balanço de forças entre o carregamento e a força hidrodinâmica gerada no mancal a cada instante de tempo. A interação do problema hidrodinâmico do filme de óleo e o problema de dinâmica do eixo é responsável pela geração de um campo de pressões continuamente variável com o tempo. A partir do conhecimento deste campo de pressões, as características operacionais, tais como vazão de óleo e perdas, podem ser determinadas, permitindo a otimização dos mancais em análise. Os resultados obtidos neste trabalho são comparados com resultados numéricos e experimentais existentes na literatura, alcançando-se boa concordância entre os mesmos
The Application of Monte Carlo Method for Sensitivity Analysis of Compressor Components
No full textThe robustness evaluation of compressor components must take into account the variations in the mechanical properties of the material (such as Young\u27s modulus and mass density), geometric parameters (as radius, thickness, length) and loads. Sometimes, the combination of these factors could result in the component failure. The correct way to assess the robustness of the component (considering the parameters variation) is through the statistical analysis using probabilistic design techniques. One methodology is the application of Monte Carlo method to generate random combinations of geometrical, loads and physical parameters that produce the same real component variation. This work shows the application of probabilistic analysis (Monte Carlo method) to estimate the scatter of resonance modes frequency of a discharge tube. The input parameters are the geometry, material properties and damping spring. The alternatives are analyzed by finite element method
Desenvolvimento sustentável para pequenos municípios através do turismo rural: uma metodologia de avaliação do potencial de serviços turísticos
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.O mercado para o turismo tem-se voltado, nos últimos anos, para novos usuários e para novos produtos. Fatores como a globalização têm ocasionado estas modificações, onde a competitividade passa a existir, vislumbrando a necessidade de conhecimento do potencial turístico na consolidação do desenvolvimento sustentável para as comunidades onde o turismo não é visto como alavanca de progresso. O município tem o produto e, na maioria das vezes, não tem conhecimento de sua potencialidade. Esta dissertação apresenta uma metodologia própria, em que propõe-se avaliar estas potencialidades por meio do turismo rural voltado para o desenvolvimento sustentável. Para tanto, formula-se e aplica-se esta metodologia em dois municípios no sudoeste de Goiás, como estudo de caso. Analisa-se diversas determinantes no cenário que norteia o turismo: lançamento do serviço no mercado, desenvolvimento das etapas de planejamento, levantamento macro ambiental, pesquisa de análise de oportunidades, gerenciamento estratégico, comunicação e política, avaliação e controle de resultados voltados para a satisfação do turista. The market for the tourism has been aimed at new users and new products in the last years. Factors such as globalization has caused these modifications, and competitiveness begins to exist, showing the necessity to know tourist potential in the consolidation of the sustainable development to the communities where tourism in not seen as a lever to progress. The municipal district has the product and, most of the times, it is not aware of its potentialities. This dissertation presents a distinct methodology that proposes to evaluate these potentialities through the rural tourism aimed to sustainable development. For such, this methodology was created and applied in two municipal districts of the southwest region of Goiás, as a case study. Several determinants are analyzed in the scene that guides tourism: launching of the service in the market, development of the planning stages, macro-environmental survey, research of opportunity analysis, strategic management, communication and politics, evaluation and control of the results directed to tourist's satisfaction
Experimenteel onderzoek aan de stroming in een reverse flow cycloon: Laser Doppler snelheidsmetingen en visualisatie van de precederende vortexkem
No full textKramers Laboratorium voor Fysische TechnologieApplied Science
High-tech meets end-user
No full textOne challenge within the high-tech sector is to develop products that end users will actually need and will be able to use. One way of trying to match the design of high-tech products to the needs of end users, is to let researchers and designers interact with them via a human-centred design (HCD) approach. One HCD project, in which the author works, is studied. It is shown that the relation between interacting with end users and making design decision is not straightforward or "logical." Gathering knowledge about end users is like making a grasping gesture and reduces their otherness. Making design decisions is not based on rationally applying rules. It is argued that doing HCD is a social process with ethical qualities. A role for management is suggested to organize HCD alternatively to stimulate researchers and designers to explicitly discuss such ethical qualities and to work more reflectively. © 2009, IGI Global
SPECTRAL SIGNATURES OF NON-ADIABATIC DYNAMICS
No full textAuthor Institution: School of Chemistry, University of Bristol, Bristol BS8 1TH, UKNon-adiabatic interactions between molecular electronic states give rise to a wide range of spectroscopic phenomena: e.g. perturbations of energy levels, intensity stealing in forbidden transitions, wide amplitude dynamics on multiple potential surfaces, quantum interference, the opening of dissociation pathways, and the control of the resulting energy disposal. This paper will illustrate some of these signatures, with particular attention to studies using high resolution photofragment translational spectroscopy. In small polyatomic molecules, such as HCO and HO, the effects of non-adiabatic surface crossings appear in the rotational behaviour, but in the vibrational behaviour for larger molecules such as pyrrole and phenol. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ R.N.Dixon. \textit{Chemical Society Reviews}, \textbf{23}, 375, 1994.\\ R.N. Dixon, D.W. Huang, X.F. Yang, S. Harich, J.J. Lin and X. Yang. \textit{Science}, \textbf{285}, 1249, 1999.\\ B. Cronin, M.G.D. Nix, A.L. Devine, R.N. Dixon and M.N.R. Ashfold. \textit{Phys. Chem. Chem. Phys.}, \textbf{8}, 599, 2006
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