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In-plane compression of preconditioned carbon/epoxy panelsRivera, Luis A. January 2004 (has links)
This thesis investigates the effects of damage characteristics on residual compressive strength (RCS) of 4-mm thick preconditioned carbon/epoxy quasi-isotropic panels through the study of their compressive behaviour. Results of 2-mm thick preconditioned panels mostly from a previous study are also analysed. The preconditions of varying sizes include impact damage, quasi-static damage, single and multiple artificial delaminations of circular and elliptical shapes embedded at different through-the-thickness (TTT) locations, hemispherical-shaped domes of different curvature and depth and open holes. The mechanisms of impact damage and the characteristics of energy absorption were dependent on panel thickness and incident kinetic energy (IKE). A damage threshold for compressive strength (CS) reduction was found at 455-mm2 and 1257 mm2 for 2- and 4-mm thick panels, respectively. Panels affected by the presence of internal delaminations followed a sequence of prebuckling, local and global buckling (mode I) and postbuckling (mode II) in both the longitudinal and transverse directions. Their compressive failure was related to mode I to II transition. Possibility of delamination propagation was examined using response characteristics on the basis of the sequences. Evidence of delamination propagation was found only in panels with large damages and was not sensitive to RCS. For low and intermediate IKEs the effect of impact damage could be simulated with a single delamination (2-mm thick panels) and 3 delaminations of medium size (4-mm thick panels). For high IKEs, the additional effect of local curvature change was significant. The combined effect of delamination number, size and curvature change determines the RCSs. It was demonstrated that the present method of embedding artificial delaminations proves to be very useful for studying RCS of impact-damaged panels via the establishment of response characteristics and their links to the effects of the preconditions on them. This thesis also presents two analytical models, one for deflection of transversely loaded panels and the other one for the prediction of compressive strength retention factor (CSRF) based on the correlation between the ratio of maximum transverse force to initial threshold force and the CSRF, observed experimentally in thick panels.
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Vibration And Impact Induced SoundNarla, Subrahmanya Prasad 07 1900 (has links)
Sound generated by impacting structures is of considerable importance in noise control. Sound is generated by a vibrating structure by inducing pressure fluctuations in the surrounding medium. Impact induced noise is the sound generated by a vibrating structure subjected to motion constraint. In such problems one has to study the vibration behavior of the oscillator, the impact mechanics, and the emanating acoustic field dynamics.
A literature review carried out points to the fact that though there has been considerable work on vibration behavior of impact oscillators and the acoustics of impact of rigid masses, there is very little work reported on the sound generated due to vibration and impact. This thesis couples vibration analysis of oscillators undergoing impact with its acoustic behavior. The vibration behavior is nonlinear on account of the impact. Therefore the vibration analysis as well as the resulting acoustic field analysis has to be in the time-domain. This investigation is concerned with the effect of structural dynamics, impact dynamics, and acoustic field boundary conditions, on the sound pressure generated due to vibration and impact.
We have considered a single degree of freedom as well as a flexible Euler-Bernoulli beam vibration model. The former is the simplest for studying vibro-acoustic response. The numerical model of the beam is derived using the finite element method resulting in a finite dimensional system with more than one degree of freedom. The dynamics of each degree of freedom are distinct in terms of amplitude and phase and are a function of the nature of linear dependence on other degrees of freedom and the nature of excitation. An impacting beam introduces interesting interactions between the dynamics of the degrees of freedom as a consequence of nonlinearity due to the motion constraint.
The impact of the oscillator mass with a barrier is modeled using a simple coefficient of restitution model based on Hertzian contact theory. There is velocity reversal on contact with the barrier. The contact force is finite acting within a finite interval of time. The contact force is assumed to vary in time during the contact interval. This effectively models contact as linearly elastic.
The pressure perturbation due to vibration of the oscillator mass is shown equivalent to the pressure perturbation due to an acoustic dipole. The acoustic dipole is placed at the equilibrium position of the vibrating mass. The dipole pressure is then a function of motion of the oscillator. In the case of a single degree of freedom oscillator the dipole axis is along the direction of motion. The sound pressure due to a vibrating beam is modeled as an array of acoustic dipoles placed at the finite element nodes of the beam and stationary at the beam's static equilibrium configuration. The dipole axis is once again aligned with the direction of vibration of the beam that is transverse to the beam neutral axis. Anechoic as well as perfectly reflecting acoustic boundary conditions are simulated in the time-domain.
The resulting governing equation of motion of the single degree freedom oscillator as well as the beam are integrated numerically in time to compute its response.
The acoustic pressure is shown to be critically dependent on the excitation frequency of the oscillator, dynamic properties of the oscillator, coefficient of restitution of impact and impact dynamics, and acoustic field boundary conditions.
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Measuring the Impact of Community-University Research Partnership Structures: a case study of the Office of Community-Based Research at the University of VictoriaLall, Nirmala 27 October 2015 (has links)
This research study focused on measuring the impact of structures that support community-university research partnerships. The broad research question asked: How can we determine the impact of community-university research partnership support structures such as the Office of Community Based Research at the University of Victoria, within the university and within local, regional, national and international communities? Methods of inquiry included: participatory research, institutional ethnography and case study. These are among an increasing number of research approaches consistent with what is called engaged scholarship. Congruent with the methods of inquiry, methods of investigation included: in-context immersion, participant-observer-listener, use of available documents and information, use of an impact assessment framework prototype designed pre-data collection, key informant interviews, field notes, research journaling and the writing process. Data contributing to this study were drawn from key informant interviews. Interview participants were situated within local, regional, national and international communities. Methods of analysis included: a two-pronged approach to organising data, deductive and inductive approaches, the lens of praxis, and the prototype as an analytical framework. Assessment as praxis is proposed as broad analytic framework. Theory was constructed through data analysis. This study’s data and analysis point to impact assessment as a cycle of inquiry and eight elements that inform impact on and through community life and impact on and through the university. The proposed Impact Assessment and Measurement Framework (IAMF) includes eight elements: coupling intention with impact, spheres of impact, categories of impact, conditions of impact, points of impact, impact-focused documentation, multiple perspectives of impact, and impact assessment and measurement statements. Contributions of this study include: recognition of staff who support community-university research partnerships through their varied work spaces, research councils as a type of support structure, impact assessment as a cycle of inquiry, explicating impact through elements of impact assessment, and a literature consolidation of impact assessment in the context of support structures. Future research may include revision and refinement of the IAMF across different types of community-university research partnership support structures. / Graduate
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Advanced Impact Analysis: the ADVIAN® method - an enhanced approach for the analysis of impact strengths with the consideration of indirect relationsLinss, Volker, Fried, Andrea 01 June 2009 (has links)
An enhanced approach for the impact analysis is presented. Impact analyses play an important role in future
research analysis as part of the scenario techniques in the strategic management field. Nowadays, they are also
applied for the description of mutual relationships of tangible and intangible resources in organisations. The
new method is based on currently existing methods using a cross impact matrix and overcomes some of their
drawbacks. Indirect impacts are considered together with their impact strengths. A modification of the impact
matrix is not necessary. Simple examples show that the new method leads to more reasonable and stable results
than the existing methods. The new method shall help analysing the complexity of social systems in a more
reliable way.
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Impact of land use on water resources of the Modder River basin in central South AfricaWelderufael, W.A., Woyessa, Y.E. January 2010 (has links)
Published Article / Along the path of water flowing in a river basin are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves abstraction of water in the upstream catchment. Increased water withdrawal at upstream level is an issue of concern for downstream water availability to sustain ecosystem services. The Modder River basin, located in the central South Africa, is experiencing intermittent meteorological droughts causing water shortages for agriculture, livestock and domestic purpose. To address this problem a technique was developed for small scale farmers with objective of harnessing rainwater for crop production. However, the impact of a wider adoption of this technique by farmers on the water resources has not been quantified. In this regard, the SWAT hydrological model was used to simulate the impact of such practice on the water resources of the river basin. The scenarios studied were: pasture (PAST), conventional agriculture (Agri-CON) and agriculture using rainwater harvesting (Agri-IRWH). The result showed that the highest mean monthly direct flow was obtained on Agri-CON land use (18 mm), followed by PAST (12 mm) and Agri-IRWH land use (10 mm). The Agri-IRWH scenario reduced runoff by 38% compared to Agri-CON, which justifies its intended purpose. On the other hand, it was found that the Agri-IRWH contributed to more groundwater recharge (40 mm) compared to PAST (32 mm) and Agri-CON (19 mm) scenarios. Although, there was a visible impact of the rainwater harvesting technique on the water yield when considered on a monthly time frame, the overall result showed that there was a substantial benefit of using the rainwater harvesting technique for agricultural production (Agr-IRWH) without impacting significantly on the mean annual water yield.
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À la croisée des regards : production d'une étude photographiqueBlache, Martin January 2013 (has links)
Ce mémoire est le fruit d'un questionnement sur l'impact émotif du positionnement des yeux de la personne que l'on regarde sur notre propre perception de son regard. Dans les recherches actuelles sur les réactions émotives, le regard ne semble pas avoir été considéré autant que le fut l'expression faciale des gens; c'est précisément ce vide que cette recherche de type production cherche à combler. Les modèles des recherches sur les expressions faciales ont généralement les yeux fixés droit devant. La présente recherche isole différentes positions des yeux à partir de neuf perspectives avec des modèles qui ont tous une expression neutre. Ce mémoire a non seulement permis de produire une banque photographique, mais il constitue d'abord et avant tout une réflexion sur le regard, démontrant plus spécifiquement son impact dans différents types de photographie. L'observation des yeux de plusieurs modèles dans les situations de prises de vue studio a permis de concrétiser une observation rationnelle de leurs regards. En fait, seulement certains regards particuliers se sont avérés pertinents dans l'interpellation émotive qu'ils créent en étant photographiés. Les perspectives de caméras utilisées en prise de vue simulant notre perspective visuelle face à une personne révèlent clairement qu'il y a certains regards qui nous font réagir. Les idées préconçues au sujet de regards qui auraient dû, à mon sens, exprimer une émotion se sont avérées souvent fausses. Des émotions perçues avec certains angles (caméra - modèle - direction du regard) se dévoilèrent souvent communes à tous. Ce qui démontre que notre perception de l'autre est influencée par le regard autant que par l'expression du visage. Ces observations sont d'ailleurs contenues dans une analyse critique des résultats et des observations appuyées par des tableaux, suivie de différents corollaires. Une banque de 368 photographies a également été produite comme document de recherche.
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Impact des capacités et des orientations stratégiques sur la performance : profils distincts de PME manufacturièresChabot, Étienne January 1998 (has links)
Cette recherche a pour principal objectif dans un premier temps, l’identification de profils distincts d’entreprises (au niveau des capacités et des orientations stratégiques) dont les niveaux de performance varient et dans un deuxième temps, une meilleure compréhension ces divers profils afin d’aider les gestionnaires à mieux gérer les destinées des PME manufacturières québécoises. Elle met surtout l’accent sur une meilleure compréhension des dimensions marketing et technologique et de la façon dont elles interagissent entres elles dans l’établissement de ces mêmes profils. Pour vérifier l’existence de tels profils, nous avons étudié conjointement les capacités distinctives en marketing et en technologie, les capacités en gestion de l’interface entre les fonctions marketing et R&D, les capacités en comportement entrepreneurial et les orientations des stratégies marketing et technologique que les entreprises mettent en oeuvre. Nous visons à déterminer des profils distincts auxquels sont associés des niveaux de performance différents en termes de fréquence d’innovation, de succès commercial et financier du portefeuille d’innovations et de performance globale d’entreprise. Afin d’identifier ces profils, nous avons utilisé une banque de données recueillies par Chénier (1997) portant sur 101 PME manufacturières du Québec. L’information à propos de ces entreprises a été recueillie par le biais d’entrevues individuelles face-à-face auprès de PDG d’entreprises ou, le cas échéant, d’un actionnaire ou d’un directeur de service. Ces 101 entreprises appartiennent à un secteur unique d’activité soit celui de la machinerie et de l’équipement industriel et proviennent des régions de l’Estrie, Chaudière-Appalaches, Mauricie-Bois-Francs, Montérégie et des Laurentides. Pour les fins de nos analyses, nous avons principalement utilisé des procédures d’analyses par regroupements hiérarchiques selon la méthode Ward. Après avoir effectué de multiples analyses visant à mieux comprendre le comportement des PME, nous identifions un certain nombre de profils distincts d’entreprises que nous décrivons et interprétons. Les principales contributions théoriques de cette recherche se situent au niveau de la considération conjointe des capacités et des orientations stratégiques dans l’identification de profils distincts d’entreprises. En effet, à notre connaissance, aucune autre recherche n’étudie conjointement l’effet des capacités distinctives en marketing, en technologie, en gestion de l’interface inter-fonctionnelle entre le marketing et la R&D, en comportement entrepreneurial et des orientations des stratégies marketing et technologique sur la performance de l’entreprise. À la lumière des résultats cette étude, il semble se dégager que les entreprises qui obtiennent les meilleures performances sont celles qui mettent en oeuvre une stratégie technologique orientée vers l’innovation ainsi que la R&D comme source interne d’innovation et qui, conjointement à la mise en oeuvre de cette stratégie technologique, ont une stratégie de marketing qui vient supporter ces efforts investis en R&D. De plus, il semble assez évident que les capacités distinctives en marketing et en technologie jouent un rôle important dans la réussite qu’obtiendra l’implantation de ces stratégies. Il appert en effet que les entreprises qui sont les plus performantes soient celles qui possèdent de fortes capacités distinctives à différencier leurs produits, à générer une image forte et à bien servir leur clientèle en établissant une relation avec cette dernière. La stratégie marketing de ces dernières se démarque par la mise en marché de produits surtout de spécialité de très haute qualité et offerts en variété. De plus, ces dernières possèdent de très fortes capacités à développer et à offrir des produits de qualité ainsi que de très bonnes capacités de production. Elles sont toujours à l’affût des nouvelles découvertes technologiques dans leur industrie et leur stratégie technologique se distingue par de forts investissements en innovation de produits par rapport à la concurrence et est fortement orientée vers l’innovation de produits et de procédés. Elles privilégient la R&D comme source interne d’innovation et ne considère pas vraiment les sources externes d’innovation. Sachant que les PME contribuent dans une forte mesure au renforcement du tissu économique régional et national, que leur poids économique ne cesse d’augmenter et que comme les grandes entreprises, elles se doivent d’innover continuellement si elles veulent survivre et croître, il apparaît approprié d’identifier les profils qui leur permettront de devenir et de demeurer concurrentielles dans un contexte où les compétiteurs proviennent des quatre coins du globe. En effet, nous pensons qu’en comprenant mieux les diverses capacités qu’elles acquièrent et qu’elles entretiennent ainsi que les diverses orientations stratégiques qu’elles adoptent, nous sommes plus en mesure de comprendre le comportement le plus adéquat qu’elles devraient adopter selon le type de performance qu’elles recherchent.
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Incorporation of Sustainable Development Concerns in Regulatory Impact AssessmentsRitzka, Martin Stefan January 2016 (has links)
Regulatory Impact Analyses (RIA) are carried out in order to determine how a project or regulation affects the economy, society and environment. Traditionally, RIAs are carried out through cost benefit assessments and by monetizing different variables in order to assist policymakers with their decision. The main disadvantage of it, is that highly relevant social and environmental factors are difficult to quantify, thus providing weak or "incomplete" support to policy-makers in their final decision and enabling long-term consequences. An option to improving RIAs, is by taking into account such factors with the introduction of Sustainable Development (SD) concerns early in the decision making process. This is a trend that has been gaining more momentum and support, especially in OECD and EU members. The shift towards the inclusion of such concerns at a regulatory and legislative level nonetheless still presents itself to be a challenge and has wide room for improvements. On this research, four different countries and the European Union are analyzed and compared, presenting their current RIA practices and how much they take into account sustainability concerns with the intent on showing where can they be improved and better included.
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Understanding coaches' learning : process, practice and impactStodter, Anna January 2014 (has links)
Although it seems clear that coaches become effective practitioners through idiosyncratic combinations of learning experiences (Werthner & Trudel, 2009), little is known about how and why this occurs and impacts on coaching knowledge and practice (Cushion et al., 2010). This research sought to understand the processes and impact of coaches learning in the context of UK youth football coaching, specifically centring on a formal education course. The research process utilised a pragmatic and integrated perspective, influenced by impact evaluation frameworks (e.g. Coldwell & Simkins, 2011). A group of 25 coaches were investigated at different points over a period of a year and a half, using a mixture of semi-structured interviews, systematic observations, video-based stimulated recall interviews and course observations, to build up increasingly in-depth levels of data. Using the principles of grounded theory methodology (Strauss & Corbin, 1998) as well as mixed analyses of variance (ANOVA), changes in the knowledge use and practice behaviours of course candidates, and equivalent coaches not undertaking formal education, were compared. The course had subtle impacts on coaches knowledge conceptions in interaction with wider knowledge sources, yet impact on practice was generally demonstrated only in the areas of questioning content and individually directed coaching interventions. Mismatches between the espoused theory of the course and what the candidates actually perceived, as well as a lack of individualised support to overcome disjuncture (Jarvis, 2006) created barriers to learning, preventing integration of theoretical conceptions into altered coaching practice. A substantive grounded theory was generated to explain the underpinning double-loop cognitive filter and reflective feedback processes involved in coaches learning. The model demonstrated that practitioners learning, guided by existing biography and driven by a practical focus on what works , was heavily influenced by context. Meaningful learning connected knowledge with implementation in practice through reflection. These processes help explain uneven learning across individuals; addressing for the first time questions of what works , how , 'why', and for whom in coach learning (McCullick et al., 2009). Thus the results generate an understanding of coaches learning which can be practically relevant in fostering better opportunities to enhance the development of capable and creative coaches.
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Stress och dess påverkan på sjuksköterskor på akutmottagningar : En litteraturstudie ur sjuksköterskans perspektivLennartsdotter, Signe, Svensson, David January 2016 (has links)
Dysfunktionell stress bland sjukvårdspersonal är ett ökande problem i dagens samhälle. En av de vanligaste anledningarna för sjukfrånvaro bland sjukvårdspersonal är psykisk ohälsa och värk i rörelseapparaten på grund av dysfunktionell stress. Sjuksköterskor som måste ta itu med svåra skador och avlidna människor löper större risk att utsättas för höga nivåer av dysfunktionell stress. Ökad utsatthet för stress kan leda till en försämrad prestationsförmåga och en ökad risk för misstag som kan äventyra patientens säkerhet och hälsa. Litteraturstudien har för avsikt att beskriva orsaker till stress och dess påverkan på sjuksköterskan på en akutmottagning. Studien bygger på 10 vetenskapliga artiklar, sex kvantitativa samt fyra kvalitativa. Litteraturgranskningen resulterade i två teman. Administrativ och organisatorisk stress: Administrativ och organisatorisk stress härstammar primärt från en bristande blandning av personal med hög och låg kompetens, underbemanning, överbeläggningar samt omvårdnadskrävande patienter. Konflikter på grund av skillnader i senioritet, tjänstgöringstid, skillnader i vanor och arbetssätt ligger till grund för stress. Dåligt stöd har en stor påverkan på hur sjuksköterskor upplever stress. Vårdpersonal som känner stöd från kollegor och ledning upplever en större arbetstillfredsställelse, högre arbetsmoral och upplever mindre stress i arbetsvardagen. Patientrelaterad stress: Sjuksköterskor utsätts för våld samt traumatiska händelser i sitt vardagliga arbete som upplevs vara en stor orsak till stress. Ångest, skuldkänslor, rädsla samt utmattning är några känslor sjuksköterskor upplever efter hot och våld eller traumatiska händelser. Stress kan leda till minskad koncentrationsförmåga och fokus bland sjuksköterskor vilket kan resultera i en försämrad vårdkvalité. Sjuksköterskor som utsätts för traumatiska händelser löper risk för att utveckla PTSD (posttraumatisk stress disorder). För att kunna tillfredsställa grundläggande behov, undvika lidande, bidra till ökat välbefinnande och inge trygghet hos patienten. Är det viktigt med en ökad insikt i sjuksköterskans stressfyllda arbetssituation på akutmottagningar.
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