952 resultados para attrition and chipping
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Starting with the question “How can University level Engineering Education be developed in such a way so as to enhance the quality of the student learning experience?”, this discussion paper proposes an approach to engineering education developed by a senior engineering educator working alongside a pedagogical researcher in an attempt to engage colleagues in contemporary debates about the issues currently faced across the Sector. Such issues include difficulties with recruiting students onto programmes as well as high levels of student attrition and failure. Underpinned by three distinctive concepts: Synergy, Variety & Relationships (S+V+R), the approach brings together pedagogic and engineering epistemologies in an empirically grounded framework in such a way so as to provide an accessible and relevant learning approach that, if followed, engenders student success [S2]. Specifically developed with the intention of increasing retention and positively impacting student success [S2], the S+V+R=S2 approach provides a scholarly and Synergetic (S) approach to engineering education that is both innovative and exciting. Building on the argument that Variety (V) in education is pivotal to promoting originality and creativity in learning and teaching, this paper shows how, by purposefully developing a range of learning and teaching approaches, student engagement and thus success can be increased. It also considers the importance of Relationships (R) in higher education, arguing that belonging and relationships are crucial factors impacting student experiences. When taken together (Synergy, Variety and Relationships) and applied within an Engineering Education context, students are provided with a unique learning environment – one that both promotes individual success and improves organisational effectiveness. The uniqueness of the approach is in the synthesis of these three concepts within an Engineering Education epistemology.
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Learning and teaching approaches to engineering are generally perceived to be difficult and academically challenging. Such challenges are reflected in high levels of student attrition and failure. In addressing this issue, a unique approach to engineering education has been developed by the paper authors. This approach, which is suitable for undergraduate and postgraduate levels, brings together pedagogic and engineering epistemologies in an empirically grounded framework. It is underpinned by three distinctive concepts: Relationships, Variety & Synergy. Based upon research, the R + V + S approach to Engineering Education provides a learning and teaching strategy, which in enhancing the student experience, increases retention and positively impacts student success [S2]. Based on the study findings, this paper shows how, by designing engineering education around the concepts of Relationships, Variety and Synergy, the student learning experience becomes one that is academically challenging yet beneficial to both students and engineering educators. The challenge is to widen and test the approach in other areas of engineering education, before going on to investigate the value of the approach in other disciplines.
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Thesis (Ph.D.)--University of Washington, 2016-08
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This review illustrates, through a series of case histories, how oral medicine insights aid the diagnosis and management of patients with excessive tooth wear. The cases reviewed are drawn from the records of 500 southeast Queensland patients referred to the author over a 12 year period. Patients most at risk of dental erosion have work and sports dehydration, caffeine addiction, gastro-oesophageal reflux, asthma, diabetes mellitus, hypertension or other systemic diseases or syndromes that predispose to xerostomia. Saliva protects the teeth from the extrinsic and intrinsic acids which cause dental erosion. Erosion, exacerbated by attrition and abrasion, is the main cause of tooth wear. These cases illustrate that teeth, oral mucosa, salivary glands, skin and eyes should be examined for evidence of salivary hypofunction and attendant medical conditions. Based on comprehensive oral medicine, dietary analyses and advice, it would seem patients need self-management plans to deal with incipient chronic tooth wear. The alternative is the expensive treatment of pain, occlusal damage and pulp death required to repair the effects of acute severe tooth wear.
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Acid demineralization of teeth causes occlusal erosion and attrition and associated non-carious cervical lesions at sites relatively unprotected by saliva. Associations of occlusal pathology and cervical lesions were looked for in 450 patients with toothwear, and 174 subjects with cervical lesions were identified. Associations of occlusal attrition, or erosion, or no wear, with cervical lesions at 72 buccal and lingual sites were recorded from epoxy resin replicas of the subjects' dentitions (3241 teeth). Criteria used to discriminate occlusal erosion from attrition; and shallow from grooved and wedge-shaped cervical lesions were delineated by scanning electron microscopy (SEM). In the absence of occlusal pathology, cervical lesions were very rare (
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Background: Motive-oriented therapeutic relationship (MOTR) was postulated to be a particularly helpful therapeutic ingredient in the early treatment phase of patients with personality disorders, in particular with borderline personality disorder (BPD). The present randomized controlled study using an add-on design is the first study to test this assumption in a 10-session general psychiatric treatment with patients presenting with BPD on symptom reduction and therapeutic alliance. Methods: A total of 85 patients were randomized. They were either allocated to a manual-based short variant of the general psychiatric management (GPM) treatment (in 10 sessions) or to the same treatment where MOTR was deliberately added to the treatment. Treatment attrition and integrity analyses yielded satisfactory results. Results: The results of the intent-to-treat analyses suggested a global efficacy of MOTR, in the sense of an additional reduction of general problems, i.e. symptoms, interpersonal and social problems (F1, 73 = 7.25, p < 0.05). However, they also showed that MOTR did not yield an additional reduction of specific borderline symptoms. It was also shown that a stronger therapeutic alliance, as assessed by the therapist, developed in MOTR treatments compared to GPM (Z55 = 0.99, p < 0.04). Conclusions: These results suggest that adding MOTR to psychiatric and psychotherapeutic treatments of BPD is promising. Moreover, the findings shed additional light on the perspective of shortening treatments for patients presenting with BPD. © 2014 S. Karger AG, Basel.
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Työn tavoitteena oli selvittää koivun kasteluvarastoinnin kannattavuus selluteollisuudessa. Lisäksi tutkittiin, kuinka kastelu vaikuttaa puuaineeseen varastoinnin aikana ja kuinka koivun kasteluvarastointi vaikuttaa puun kuorintaan ja haketukseen, keitettävyyteen, vaalenevuuteen sekä sellun laatuun. Enocellin puukentälle rakennettiin kasteluvarasto, jossa varastoitiin 40,000 m3sob koivua. Kastelu oli päällä huhtikuusta lokakuuhun asti. Kastelun vaikutusta puuaineen muutoksiin arvioitiin lahotutkimusten avulla. Tehdaskoeajoissa verrattiin tuoretta, kasteluvarastoitua ja kuivavarastoitua koivua. Puuaines säilyi lähes muuttumattomana yhden kesän kasteluvarastoinnissa. Kastellulla koivulla terveen puun osuus oli yli 85 % kesän lopussa, kun se oli alle 20 % kuivavarastoidulla koivulla. Kuorinnan puuhäviö laskee selvästi kastelukoivulla ja myös hakkeen laatu oli parempaa kuin kuivavarastoidulla koivulla. Kastelukoivulla hakkeen kuoripitoisuus oli vain 0.13 %. Kuoren kuiva-aine oli 12 prosenttiyksikköä alhaisempi kuin kuivalla koivulla, mutta kuoren lämpöarvossa ero oli vain 1 €/ADt. Varastointimenetelmällä ei ollut vaikutusta hakkeen keitettävyyteen, mutta tuoreella puulla keitettävyys oli parempi kuin varastoidulla puulla. Sellun asetoniuutepitoisuus oli samalla tasolla tuoreella ja kastellulla puulla. Kuivalla syyspuulla uutetaso oli korkeampi, vaikka hartsisaippuan annostusta nostettiin 10 kg/ADt. Betulinolitaso oli kastellulla puulla erittäin alhainen puun hyvän kuoriutuvuuden vuoksi. Kastellun ja tuoreen puun vaalenevuus oli parempi kuin kuivalla puulla. Aktiivikloorin kulutus oli 3 – 4 kg/ADt alhaisempi kuin kuivalla syyspuulla. Puun varastoinnilla ei ollut vaikutusta sellun laatuun. Koivun kasteluvarastoinnin kannattavuus on erittäin hyvä. Tuotantokustannukset määritettiin tuoreelle, kastellulle, kierrätetylle sekä kuivalle koivulle. Kasteluvarastointi laskee tuotantokustannuksia noin 10 €/ADt verrattuna kierrätettyyn koivuun. Kuivavarastoidun puun käyttö nostaa tuotantokustannuksia noin 5 €/ADt verrattuna kastelukoivuun. Kierrätetyn ja kuivavarastoidun puun kustannusero johtuu kierrätyskustannuksista. Kasteluvarastolle, jota käytettiin kesällä 2004, takaisinmaksuaika on vain 0.4 vuotta. Jos tavoiteltu takaisinmaksuaika olisi kaksi vuotta, niin perusinvestointi 80,000 m3sob varastolle voisi maksaa noin 370 k€.
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Pyrolysis is a process for turning biomass into liquid fuel. The process consists of heating the biomass in inert conditions and quenching the resulting vapors into oil. The oil has many potential uses, such as heating fuel in peak heating plants. In order to broaden the application base and improve the quality of the oil, solids removal has to be addressed. The solids may also increase the probability of plugging in downstream equipment. The purpose of this research was to gain an understanding of the formation of solids in the pyrolysis process and to assess options for reducing the solid content of the oil. From literature it is known that the solids can be removed either by hot vapor filtration, liquid treatment or multiple cyclones. Hot vapor filtration decreases yield, but improves the stability of the oil while simultaneously removing solids and ash. Liquid treatment techniques are good for removing large particles but involve losses of pyrolysis liquid. Cyclones are a traditional robust technique used regularly in pyrolysis. In the experimental part of this thesis, a 2 MWfuel pyrolysis setup with 2 cyclones in series was operated and monitored. Solid and liquid samples were collected from various parts of the process for further examination. Sampling and sample treatment techniques were developed. The chemical properties of the pyrolysis char were also analyzed and assessed as a function of reactor temperature and fluidizing velocity. By measuring the particle size distributions it was noticed that there were much smaller particles collected from the second cyclone than fed into pyrolysis. The solids in the pyrolysis oil were even smaller. This was most likely caused by attrition and shrinkage. Due to better separation efficiency of the cyclones in large particles, excess attrition should be avoided.
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Longitudinal surveys are increasingly used to collect event history data on person-specific processes such as transitions between labour market states. Surveybased event history data pose a number of challenges for statistical analysis. These challenges include survey errors due to sampling, non-response, attrition and measurement. This study deals with non-response, attrition and measurement errors in event history data and the bias caused by them in event history analysis. The study also discusses some choices faced by a researcher using longitudinal survey data for event history analysis and demonstrates their effects. These choices include, whether a design-based or a model-based approach is taken, which subset of data to use and, if a design-based approach is taken, which weights to use. The study takes advantage of the possibility to use combined longitudinal survey register data. The Finnish subset of European Community Household Panel (FI ECHP) survey for waves 1–5 were linked at person-level with longitudinal register data. Unemployment spells were used as study variables of interest. Lastly, a simulation study was conducted in order to assess the statistical properties of the Inverse Probability of Censoring Weighting (IPCW) method in a survey data context. The study shows how combined longitudinal survey register data can be used to analyse and compare the non-response and attrition processes, test the missingness mechanism type and estimate the size of bias due to non-response and attrition. In our empirical analysis, initial non-response turned out to be a more important source of bias than attrition. Reported unemployment spells were subject to seam effects, omissions, and, to a lesser extent, overreporting. The use of proxy interviews tended to cause spell omissions. An often-ignored phenomenon classification error in reported spell outcomes, was also found in the data. Neither the Missing At Random (MAR) assumption about non-response and attrition mechanisms, nor the classical assumptions about measurement errors, turned out to be valid. Both measurement errors in spell durations and spell outcomes were found to cause bias in estimates from event history models. Low measurement accuracy affected the estimates of baseline hazard most. The design-based estimates based on data from respondents to all waves of interest and weighted by the last wave weights displayed the largest bias. Using all the available data, including the spells by attriters until the time of attrition, helped to reduce attrition bias. Lastly, the simulation study showed that the IPCW correction to design weights reduces bias due to dependent censoring in design-based Kaplan-Meier and Cox proportional hazard model estimators. The study discusses implications of the results for survey organisations collecting event history data, researchers using surveys for event history analysis, and researchers who develop methods to correct for non-sampling biases in event history data.
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Notre recherche a pour objet la persévérance aux études supérieures d’étudiants internationaux à l’Université de Montréal (UdeM) inscrits en programme de recherche (maîtrise et doctorat). L’objectif général de cette étude est d’explorer leurs conditions de vie et d’études afin de tendre vers une compréhension approfondie leur persévérance à l’UdeM. Constatant l’augmentation des migrations étudiantes, nous avons choisi de nous intéresser aux expériences sociales et universitaires d’étudiants internationaux. Des étudiants en mobilité internationale arrivent dans un pays et une université qu’ils ne connaissent pas ou peu et dans une nouvelle ville et une nouvelle culture qui leur sont souvent étrangères. Toutefois, nous ignorons beaucoup des conditions de vie et d’études des étudiants internationaux aux cycles supérieurs alors qu’ils jouent un rôle clé au chapitre des performances économique et scientifique des pays et institutions qui les accueillent. Dès lors, nous voulons comprendre comment des étudiants internationaux inscrits en programmes de recherche (maîtrise et doctorat) persévèrent à l’Université de Montréal. Cette thèse expose donc les points relatifs aux conditions d’accueil, d’intégration et de formation d’étudiants internationaux inscrits en programme de recherche à l’Université de Montréal. Nous partons des contextes canadiens et québécois de l’internationalisation de l’enseignement supérieur pour analyser la trame de l’expérience desdits étudiants, depuis les conditions scolaires, sociales et personnelles de leurs milieux d’accueil. Ainsi, la thèse nous plonge dans l’univers de ces étudiants et présente de nombreux points d’intérêt et une contribution à la sociologie de l’enseignement supérieur. Nous avons analysé les aspects relatifs aux caractéristiques des étudiants susceptibles de favoriser ou compromettre leur persévérance (Tinto, 1993) et les expériences scolaires et sociales de ces étudiants et le sens qu’ils donnent à ces expériences (Dubet, 1994; Rochex, 1995) et, enfin, nous avons exploré les trois temps de l’affiliation (Coulon, 1997). La question de recherche est la suivante : quels sont les aspects associés aux caractéristiques des étudiants (Tinto), à leurs expériences sociales (Dubet) et à l’apprentissage du métier d’étudiant (Coulon) susceptibles d’influencer la persévérance aux études chez les étudiants internationaux ? En ce qui concerne la méthodologie, cette recherche est de type exploratoire et repose sur une démarche d’investigation qualitative. Notre étude s’est attachée à décrire le cheminement scolaire des étudiants internationaux, nous avons tenté de tirer du sens de données institutionnelles mises à disposition. Des entretiens auprès de huit étudiants internationaux ont été réalisés. Nous proposons un survol des facteurs freinant ou favorisant la poursuite des études. Finalement, l’analyse compréhensive des entretiens suggère une forte capacité de résilience et l’importance d’une solidarité entre étudiants internationaux, en dépit de l’absence de bourses d’études ou d’autres soutiens financiers. Concernant leur intégration sociale et académique, si le Canada est décrit comme une société accueillante, les étudiants internationaux ont encore à surmonter des barrières culturelles et linguistiques, ils souffrent également d’un manque d’amitiés interculturelles faisant en sorte qu’ils ressentent un malaise général. Les échos de leurs récits suggèrent également l’importance des interactions de qualité avec leurs directions de recherche. Les étudiants internationaux ont besoin du soutien intellectuel, moral et financier de leur direction de recherche. Ces dernières sont souvent et systématiquement décrites comme première, voire unique, source d’informations. Elles sont aussi reconnues comme favorisant la persévérance aux études. Dans un tout autre ordre de déterminant, les étudiants internationaux mentionnent également que leur bien-être (physique et psychologique) dépend également de leur alimentation et la pratique de leur religion. Par exemple, certains sont véritablement en lutte pour accepter une alimentation totalement différente de celle de chez eux. De toute évidence, l’alimentation, la langue et la religion sont décrites comme véhicule de maintien de leur identité culturelle, au Canada et ce maintien est important pour leur bien-être et leur confort général dans le pays d’accueil. La recherche a permis de rendre plus audible la vie universitaire et sociale de ces étudiants jusque-là méconnue au Québec et à Montréal. L’approche exploratoire et compréhensive a montré que les migrations pour études répondent avant tout à des choix individuels liés à des aspirations sociales et professionnelles élevées. Mais, la décision de persévérer dépend de l’interrelation entre les stratégies individuelles et les contraintes migratoires, économiques et sociales. La thèse contribue à une meilleure compréhension de l’expérience des étudiants internationaux, notamment en montrant comment leur persévérance s’accompagne d’une fragilité et ces connaissances sont importantes pour les universités qui cherchent à accroître leur place sur le marché international de l’enseignement supérieur.
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Profit, embezzlement, restitution. The role of the traitants in the Nine Years War and Chamillart’s tax on financial benefits The aim of this article is to revisit the question of the financiers in Old Regime France. It starts with an analysis of the discourses about the financiers under the Absolute monarchy that underlines the complexity of their relationship with the government and the public. It then reviews the secondary literature and highlights the existence of competing historical interpretations (functional, political, utilitarian), which raise the question of their overall capacity to account for the role and impact of the financiers at different times. On this ground, the article focuses on a specific group of financiers, the so-called traitants d’affaires extraordinaires, during the Nine Years War. Further to a description of the specific role and scope of the activities of the various financiers responsible for helping the monarchy to raise the funds it needed to pay for its peace and wartime expenditure, the article examines the conditions and profits granted by the king in his contracts with the traitants whose services were hired for the purpose of selling royal offices in the public and advancing the revenue to the Treasury. It also explores the contractual arrangements of the companies established by the financiers to manage their operations as well as the rights and the responsibilities of their various stakeholders. These bases being laid, the article relies on the administrative correspondence relating to the traités during the Nine Years War to address a range of issues, in particular the extent to which these contracts, and other control procedures, were robust enough to deter fraud. The accounts of two traitants’ companies offer an opportunity to analyse and compare the structure of their income and expenditure (including the volume and cost of the promissory notes sold in the public to finance their payments to the Treasury), to explore the strategies of the contractors, to calculate their net profits and further discuss the problem of embezzlement. The article ends with the study of the context and debates which led to the introduction by finance minister Michel Chamillart, in 1700, of a shortfall tax on the financial profits of the gens d’affaires or traitants, the method used to determine its rate (50 % of the net benefits), its distribution among the various stakeholders (including the bailleurs de fonds or backers), and the related procedures. In total, the article argues that the relationship between the monarchy, society and the financiers under the Ancien Regime was not static and, therefore, suggests that the broad question of control and fraud must be examined against changing circumstances. With regard specifically to the Nine Years War, the article concludes that within the constraints of the Absolute monarchy, contractors offered valuable services by raising capital for the benefit of a king who ruled over a country which, at the time, was by far the wealthiest in Europe, and where ministers failed to foresee long wars of attrition and whose financial strategy was limited by the very existence of privilege. Overall, the traités were too costly to be a viable system of war financing. In these conditions, the substantial fortunes made by a handful of very successful traitants suffice to explain that the government easily gave in to public criticism against the wealth of the financiers and felt compelled, when peace resumed, to cancel the advantageous conditions offered in the treaties by taxing financial profits.
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The surface failure characteristics of different work roll materials, i.e. High Speed Steel, High Chromium Iron and Indefinite Chill Iron, used in the finishing stands of a hot strip mill have been investigated using stereo microscopy, 3D optical profilometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results show that the surface failure mechanisms of work rolls for hot rolling are very complex, involving plastic deformation, abrasive wear, adhesive wear, mechanical and thermal induced cracking, material transfer and oxidation. Despite the differences in chemical composition and microstructure, the tribological response of the different work roll materials was found to be strongly dependent on the material microstructure and especially the presence and distribution of microstructural constituents, such as the different carbide phases and graphite (in the case of Indefinite Chill Iron). Cracking and chipping of the work roll surfaces, both having a negative impact on work roll wear, are strongly influenced by the presence of carbides, carbide networks and graphite in the work roll surface. Consequently, the amount of carbide forming elements as well as the manufacturing process must be controlled in order to obtain an optimised microstructure and a predictable wear rate.
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Nesse trabalho, procurou-se estudar os mecanismos de desgaste de diversas geometrias de ferramentas cerâmicas (Al2O3 + SiCw e Al2O3 + TiC) e ferramentas de PCBN. Para isto foram realizados ensaios de torneamento com alta velocidade de corte em uma superliga à base de níquel (Waspaloy) com dureza de aproximadamente 40 HRC sob condição de corte a seco. As superligas são conhecidas como materiais de difícil usinabilidade devido à alta dureza, alta resistência mecânica em alta temperatura, afinidade para reagir com materiais da ferramenta e baixa condutividade térmica. Os resultados mostraram que o material da ferramenta e a geometria influenciaram o comportamento dos mecanismos de desgaste. de uma maneira geral, o tipo de desgaste dominante foi o de entalhe e os mecanismos foram abrasão, attrition (aderência com arrastamento) e provável difusão na maioria das ferramentas utilizadas.
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In this paper we consider the transmission problem, in one space dimension, for linear dissipative waves with frictional damping. We study the wave propagation in a medium with a component with attrition and another simply elastic. We show that for this type of material, the dissipation produced by the frictional part is strong enough to produce exponential decay of the solution, no matter how small is its size. ©2007 Texas State University.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)