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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Quelques problèmes d’optimisation de trainée : De la propulsion par rame à la collecte d’aérosol / Few problems of drag optimisation : From oars propulsion to aerosol collection

Labbe, Romain 17 October 2018 (has links)
La propulsion en aviron résulte de la compensation entre la résistance de l’eau sur la coque et l’accroche des pelles dans l’eau. Pour la collecte de brouillard à l’aide de filets, la dynamique de récupération de l’eau résulte des effets de résistance de l’air sur les gouttelettes combinés aux perturbations de l’écoulement au niveau du filet. Dans cette thèse, — centrée sur les interactions fluide/structure — nous avons cherché à optimiser l’efficacité (de la propulsion et de la collecte) du point de vue hydro et aérodynamique. Pour cela, nous nous sommes appuyés sur des expériences modèles (maquettes de bateaux d’aviron, soufflerie à brouillard) permettant de se placer dans des conditions contrôlables en laboratoire et de s’affranchir des biais humain et climatique.Dans la première partie sur l’aviron, nous avons montré quelle était la longueur de rame optimale pour la propulsion. Puis nous nous sommes intéressés à l’effet du déphasage entre les rameurs et avons montré qu’une parfaite synchronisation permet d’obtenir une vitesse maximale. Enfin, nous avons effectué une étude empirique et expérimentale sur les formes (rapport d’aspect et symétrie) de coques optimales. La seconde partie porte sur la collecte d’eau à l’aide de filets à brouillard qui a débuté par une étude de l’impact des gouttes sur une maille (fibre) du filet puis au sein d’un filet complet. Nous avons enfin étudié l’effet de l’élasticité des fibres et du drainage sur la collecte. Cette étude a mis en évidence l’importance des propriétés de mouillage des fibres sur la collecte et la conception des filets. / The rowing propulsion results from the compensation between water resistance on the hull and the attachment of the oars in the water. For fog collection using nets, the dynamics of water harvesting results from the effects of air resistance on the droplets combined with flow disturbances at the net level. In this thesis, - centered on the fluid / structure interactions - we sought to optimize the efficiency (propulsion and collection) from the hydro and aerodynamic point of view. For this, we relied on model experiments (Robot rowing boats, mist wind tunnel) to be placed in controllable laboratory conditions and to overcome human and climatic bias.In the first part on rowing, we showed what was the optimal oars length for propulsion. Then we were interested in the effect of the phase shift between the rowers and showed that a perfect synchronization makes it possible to obtain a maximum speed. Finally, we carried out an empirical and experimental study on the shapes (aspect ratio and symmetry) of optimal hulls. The second part deals with the collection of water using mist nets, which began with a study of the impact of the drops on a mesh (fiber) of the net and then within a complete net. Finally, we studied the effect of fiber elasticity and drainage on collection. This study has highlighted the importance of fiber wetting properties on net collection and design.
2

National Survey of Physicians on the Need for and Required Sensitivity of a Clinical Decision Rule to Identify Elderly Patients at High Risk of Functional Decline Following a Minor Injury

Abdulaziz, Kasim 15 January 2014 (has links)
Many elderly patients visiting the emergency department for minor injuries are not assessed for functional status and experience functional decline 6 months post injury. Identifying such high-risk patients can allow for interventions to prevent or minimize adverse health outcomes including loss of independence. For the purpose of a planned clinical decision rule to identify elderly patients at high risk of functional decline a survey of physicians was conducted. A random sample of 534 Canadian geriatricians, emergency and family physicians was selected with half randomly selected to receive an incentive. A response rate of 57.0% was obtained with 90% of physicians considering a drop in function of at least 2 points on the 28-point OARS ADL scale as clinically significant. A sensitivity of 90% would meet or exceed 90% of physicians' requirements for a clinical decision rule to identify injured seniors at high risk of functional decline 6 months post injury.
3

National Survey of Physicians on the Need for and Required Sensitivity of a Clinical Decision Rule to Identify Elderly Patients at High Risk of Functional Decline Following a Minor Injury

Abdulaziz, Kasim January 2014 (has links)
Many elderly patients visiting the emergency department for minor injuries are not assessed for functional status and experience functional decline 6 months post injury. Identifying such high-risk patients can allow for interventions to prevent or minimize adverse health outcomes including loss of independence. For the purpose of a planned clinical decision rule to identify elderly patients at high risk of functional decline a survey of physicians was conducted. A random sample of 534 Canadian geriatricians, emergency and family physicians was selected with half randomly selected to receive an incentive. A response rate of 57.0% was obtained with 90% of physicians considering a drop in function of at least 2 points on the 28-point OARS ADL scale as clinically significant. A sensitivity of 90% would meet or exceed 90% of physicians' requirements for a clinical decision rule to identify injured seniors at high risk of functional decline 6 months post injury.
4

Design och konstruktion av åror till snipa : Tillämpning av Design For Six Sigma / Design and Construction of Oars to a Gig Boat : Design For Six Sigma

Molin, Mattias, Larsson, Adam January 2023 (has links)
The oar has historically played a significant role for Sweden as a lake andcostal dominated country. For many years small boats called “snipa” wereused to gather fish by people living along the coastlines or alongside lakes.Oars was then the only option for conveying the boat forward. In today’ssociety, oar-propelled boats don’t have the same importance for people toacquire food. However, there are still reasons for a continued use of oars inactivities such as private fishing, competitive rowing or outdoor pursuits.The consumer market today is largely focused on mass production ofproducts, which often results in a reduced availability of custom-made ones.Being able to “engineer to order” is sometimes preferable due to the fact thathigh-quality and robust designs are, in certain respects, essential.Linnaeus University is conducting a research project that has vitalized atraditional Sami hunting and fishing gig boat, designed to be conveyed byoars and requires specially adapted oars for two different types of waterconditions. Currently, private consumers have limited options, for productsthat is designed for this, on the market.The purpose of this work is to describe how the established and well-knownmethodology of Systems Engineering, more specific “Design For SixSigma” (DMADOV), can be used to design and construct oars for use in twodifferent water conditions.

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