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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

Évolutions microstructurales et défauts générés par laser cladding lors du dépôt de Ni sur des moules de verrerie en alliage de Cu-Ni-Al et en fonte GL / Microstructural evolution and defects generated by laser cladding of Cu-Ni-Al alloy and flake-graphite cast iron glassmolds with Ni powder

Bourahima, Fazati 21 January 2019 (has links)
Dans l’industrie de la verrerie, le laser cladding est une technique de rechargement très innovante permettant de déposer une couche très fine d’un alliage à base de nickel pour protéger les moules (utiles à la fabrication de bouteilles en verre) de la corrosion, de l’abrasion ainsi que de la fatigue thermique. La méthode utilisée ici (fusion de poudre projetée par laser) est très courante en fabrication additive. Cette étude s’intéresse à l’impact du rechargement sur le dépôt et les substrats en Cu-Ni-Al et en fonte GL. L’influence sur la microstructure ainsi que sur le comportement mécanique a pu être étudiée (MEB et microanalyses, dureté, contraintes résiduelles ...). Nous nous sommes focalisés sur l’apparition de défauts tels que le manque d’accroche lors du laser cladding sur du Cu-Ni-Al et sur la possible fissuration lors du rechargement sur de la fonte GL. Le but est bien sûr de s’affranchir de ces défauts. Il a notamment été mis en évidence que le manque d’accroche (cas du Cu-Ni-Al) est lié à la distribution gaussienne de la poudre qui atténue la puissance incidente du laser au niveau du pic de poudre. Le manque d'accroche n'est pas détecté sur le substrat en fonte en raison de sa forte absorptivité et de sa faible conductivité thermique. Néanmoins, des fissures peuvent être observées en raison de contraintes résiduelles thermiques et de la présence d'une zone affectée thermiquement. De plus, l’analyse statistique ANOVA a permis une optimisation des paramètres de rechargement de telle sorte à obtenir une accroche dans toute la section tout en respectant les préconisations géométriques données par les Établissements CHPOLANSKY pour le cordon. / In glass industry, the laser cladding is an innovative surfacing technique allowing to deposit a very thin layer of nickel to protect glass mold (useful for glass bottle production) against corrosion, abrasion and thermal fatigue. This method (powder fusion by projection) is well known in additive manufacturing. The aim of this work is to observe the impact of the laser cladding on the coating behavior but also on the Cu-Ni-Al and flake-graphite cast iron substrates. The microstructure and the mechanical properties were studied (SEM and microanalysis, microhardness, residual stress …) around the interface cladding/substrate. The work was also focused on the defects like lack of bonding but also on cracking behavior during surfacing on cast iron. The purpose was to prevent from those defects. This work showed that the lack of bonding to the Cu-Ni-Al substrate is due to the gaussian distribution of the powder which attenuates the input laser power at its peak. The lack of bonding is not detected on cast iron substrate thanks to its high absorptivity and low thermal conductivity. Nevertheless, cracks can be observed due to thermal residual stresses and the presence of a thermal affected zone. The ANOVA technique allowed us to optimize the processing parameters in order to obtain a perfect bonding and the geometry wanted by CHPOLANSKY Establishments.
2

Specifické vývojové poruchy učení a využití speciálních pomůcek / Developmental learning ditficueties and the use of special need instruments

LEMBERGEROVÁ, Petra January 2010 (has links)
The thesis is divided into two parts - the theoretical and practical. The theoretical part describes the basic characteristics, symptoms and causes of specific learning disabilities {--} dyslexia, dysgraphia, dyscalculia and dysorthography. Deal with their diagnosis, remedy and methods how to work with children with SLD, what special tools to use what are the possibilities of integration. I have the current state of the three children with SLD and I consider the options for remedy in the practical part. The aim is to determine by questionnaire survey the tools used with working with children who have developmental learning difficulties.
3

Hyperaktivita / Hyperactivity

VELKOVÁ, Martina January 2010 (has links)
In my diploma thesis I deal with the issues of hyperactivity that has recently been a very current and discussed topic. In the theoretic part of my thesis, I specify the concept of hyperactivity and talk further about its symptoms and consequent effects. I, as well, pay close attention to the current possibilities of reeducation with a consequent focus on the programs supporting hyperactive children and their parents. The practical part of the diploma thesis consists of three parts: an interview with a pedagogue working with hyperactive children; a case report of a hyperactive child; questionnaire survey and its subsequent interpretation. The practical part of the diploma thesis focuses on the particular symptoms of hyperactivity at hyperactive children in the school environment and their consequent effects. It tries to find out the possibilities of the reeducation and remedy at the same time. In detail, it targets the help to hyperactive children and their parents offered by schools and consequently the ratio of utilization by the parents. At the very end of the practical part of the diploma thesis, I dedicate my work to an assessment of hypothesis defined by myself.
4

Automatic monitoring and control of Laser Metal Deposition Process

Byseke, David, Thunell, Alexander January 2021 (has links)
Laser metal deposition is an additive manufacturing technique that enables the manufacturing or repair of high-quality metal parts by building fine layers one at a time. To get a stable process with a low number of flaws and irregularities the process needs a fully operational and functioning control system. At PTC in Trollhättan, a production research facility that is a department of University West, several experiments have previously been conducted with an LMD machine.  The main objective of this thesis is to deliver input from available methods for automatic control and monitoring of the LMD process. The available methods are explained in the report and previous experiments that have been conducted have been documented in this thesis. Another objective of the thesis is to develop a prototype for monitoring and control of the process. Previous work has mainly used a visual-based control system that has used CMOS-, CCD-, or an infrared camera. Pyrometers and structured light scanning have also been used. Non-optical methods such as acoustical sensors and thermocouples have also been used for monitoring and control.  With the gathered information about the available control methods, a prototype has been developed to automatically control the LMD machine located at PTC. The control uses a CMOS camera to gather live imaging from the machine in order to adjust machine parameters, in real-time, to automatically control the process. The different parameters have a strong correlation to the final machine output and are also explained in the thesis.  The prototype and the gathering of data from the process have been made using Labview as an image-processing software. An evaluation of the developed prototype has been made and the different control methods have been discussed. The developed prototype measures the melt pool by using an algorithm that counts the number of pixels in the melt pool. However, further research needs to be made to determine if the measured width correlates with the actual width of the cladded string.
5

La notion de qualité de l'enseignement supérieur et son évaluation chez les acteurs dans le cadre de la transposition du Processus de Bologne : le cas des universités publiques et de l'INP-HB en Côte d'Ivoire / The notion of quality of higher education and its evaluation for the stakeholders in the framework of Bologna Process transposition : The case of public universities and INP-HB in Côte d’Ivoire.

Ble, Méagnet Désiré 27 June 2017 (has links)
La qualité de l’enseignement supérieur en Afrique est une notion très évoquée, pour en relever la dégradation, ou la nécessité d’en voir pourvus les institutions et systèmes d’enseignement.Pourtant le cadre de la transposition du processus de Bologne interroge quant au contenu et à la pertinence de cette notion dans nos pays.Au plan théorique, en rappelant l’importance de l’enseignement supérieur dans le développement socio-économique, puis le contexte de création du processus de Bologne, ainsi que l’analyse de ses principaux textes, nous avons souligné les conditions de déroulement de la transposition du processus de Bologne dans l’enseignement supérieur. Nous terminons cette partie en disséquant l’aspect de la qualité dans l’enseignement supérieur, ainsi que son évaluation en Europe et dans le monde.Dans cette étude, en approchant les acteurs de l’enseignement supérieur, par les méthodes d’entretien et de questionnaires, nous tentons de mettre en lumière la notion de la qualité et son évaluation selon le point de vue de ceux-ci. Ce sont principalement les universités publiques et l’INP-HB qui ont constitué notre terrain d’étude.Les résultats de l’étude nous montrent une qualité de l’enseignement supérieur, en particulier avec les intrants (compétences des enseignants, infrastructures et équipements) comme principales caractéristiques mais également l’insertion professionnelle et l’employabilité, marqueurs de cette qualité. / The quality of Higher Education in Africa is a very evocated word, to say its fallings or the need to see institutions and education systems with it. However, the framework of Bologna Process transposition questions about content and relevance of this notion in our countries.From the theoretical viewpoint, remembering the importance of Higher Education in socio-economic growing, then the context of Bologna Process creation, as well as the analysis of Bologna mains texts, we emphasize the circumstances of Bologna Process transposition in Higher Education. We complete this part dissecting the issue of quality in Higher Education, as well as its assessment in Europe and in the world.In this study, approaching higher education stakeholders, with interviews and questionnaires, we try to put the light on this issue and its assessment according to their view points. It’s mainly the public’s universities and INP-HB, our ground studies.Results shows us a quality of Higher Education, in particular with entrants (teacher’s abilities, infrastructures and equipment’s) as mains characteristics but equally the professional insertion and employability, clue of this quality
6

Les universités publiques à l'épreuve de la professionnalisation des études dans la réforme LMD : le cas du Sénégal / State universities put to the test of the professionalisation of higher education in the "LMD" reform : the case of Senegal

Ndior, Badara 29 May 2013 (has links)
Cette thèse a eu pour objet de montrer comment les universités d’Etat sous prétexte d’une conformité aux référentiels internationaux s’engagent dans la réforme du L.M.D et développent la professionnalisation. Le texte met en exergue les épreuves auxquelles sont soumis les Etats, notamment les pays en voie de développement comme le Sénégal, dans l’incitation à la professionnalisation des études par le milieu de l’emploi, les pouvoirs politiques, les institutions et organismes partenaires internationaux. Le statut de service public garantissant la démocratisation des savoirs transmis comme bien public est fortement examiné. La réforme de la professionnalisation des études universitaires est-elle imitable, transposable ou se construit-elle localement ? Est-elle opportune pour une université du sud et compatible avec la gratuité de l’enseignement supérieur ? Telles sont les questions essentielles auxquelles l’étude a tenté d’apporter des réponses. / The purpose of this thesis work is to show how state universities - under the pretence of accordance with international frameworks - undertake the L.M.D. reform and develop professionalization. The text highlights how states - particularly in developing countries like Senegal - come under pressure from the world of employment, political powers and international partner institutions and organisms for the development of occupational qualifications. The “public service” status as a guarantee of the democratization of the knowledge transmitted as a public good has been closely examined. Is the reform of the professionalization of higher education imitable and transferable, or is it necessarily home-grown ? Is this reform suitable for southern universities and compatible with free higher education ? These are the main questions raised and discussed in this study.
7

Rodinný příběh dětí s ADHD / Family story of ADHD diagnosed children

KRÁLOVÁ, Kateřina January 2009 (has links)
This master thesis deals with issues of children with ADHD, hyperactivity, on the second grade elementary school and their own view of themselves as a hyperactive individual using the narration method. Abstract The objective of the theoretical part was to define the terms MBD, ADHD, ADD and the narration method. The objective of the practical part was to analyze school experience of children with diagnosed ADHD, hyperactivity. I tried to consider the issues mainly from the insights of children themselves. In doing so, I stem from the theoretical part.
8

Covid-19 and its effect on consumer preference in the last-mile delivery : A study on Swedish consumers and the last-mile delivery industry in Sweden

Lindqvist, Kim, Lindgren, Mikael, Arias, Nicolas January 2022 (has links)
Background: E-commerce has experienced tremendous growth in the past few years. At the same time, the Covid-19 pandemic has swept across the world. As a result, many people became enforced to stay more at home because of restrictions and lockdowns, resulting in an even larger increase for the e-commerce industry, and some changes in consumer behavior. In relation to this, the last-mile delivery industry has seen demand shock as a result of the increased volumes within e-commerce. Purpose: The purpose of this paper aims to answer two research questions: How have Swedish e-consumer behaviors and preferences towards delivery services changed due to the Covid-19 pandemic? And how will Swedish e-consumer behaviors and preferences towards delivery services change after the Covid-19 pandemic? Method: With the research questions in mind, an exploratory inductive study was developed using qualitative and quantitative data. As a result, an interview and a survey were developed. The interview provided first-handed insights from the industry to better give an understanding of the challenges of the pandemic and the effect on consumer preferences. The survey on the other hand investigated consumer preferences regarding five different LMD service offerings: home delivery iiwithout signature, home delivery with signature, delivery to service points, delivery to parcel lockers, and pick-up at web shop's physical store. Another aspect of the survey is that the consumer preference is explored before, during, and after the pandemic.  Conclusion: The findings of this study conclude that Covid-19 has significantly impacted peoples' preferences regarding last-mile delivery preferences. As a general conclusion, consumers prefer delivery methods which reduce human contact as well as travel distance. The findings of this study will provide the industry with meaningful insights as well as contributing to the existing knowledge of last-mile delivery.
9

Understanding the Effect of Isothermal Heat Treatments on Microstructure of LMD-w Titanium Alloy (Ti-6242) - As-Built microstructure / Förstå effekten av Isotermiska värmebehandlingar på mikrostrukturen av LMD-w byggt Ti-6242

Harish, Prakruth January 2020 (has links)
The most widely used titanium alloy in the hot sections of a jet engine is Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) and with the technological advancements additive manufacturing (AM) of Ti-6242 is of great interest. Although, there is not much published related to additively manufactured Ti-6242. The project aimed to provide an experimental input for simulations of additively manufactured,laser metal deposited–wire (LMD-w) of Ti-6242. The main part of this project has been to experimentally study the effect of isothermal temperatures and holding times on the microstructural changes in as-built Ti-6242 on Ti-64 base-plate. The evaluation of micro-structural changes with isothermal temperature, holding time and cooling rates on Ti-6242 are quantified in terms of alpha laths, phase fraction by using MIPAR (image analysis software) and preliminary determine mechanical properties by performing hardness tests.The microstructures obtained through a process are highly dependent on the thermal history is it exposed to and the mechanical properties are determined by the microstructures present. In this thesis work the alpha lath thickness and the hardness of the material increases with increasing isothermal temperature. From the phase fractions obtained forthe heat treated samples an equilibrium phase diagram and a TTT diagram is plotted for as-built microstructure.
10

L'OFFRE DE FORMATION DES UNIVERSITÉS :<br />UNE ANALYSE PAR LA THÉORIE DE L'ARCHITECTURE ORGANISATIONNELLE

Biot-Paquerot, Guillaume 28 June 2006 (has links) (PDF)
Nous nous sommes attachés à analyser le processus décisionnel au sein des universités, conduisant à l'émergence de l'offre de formation, en privilégiant une approche partenariale de l'organisation. La structure de répartition de la valeur ayant un effet sur la production des flux, la dimension organisationnelle revêt une importance toute particulière. L'intégration des différentes parties prenantes permet alors de mesurer la contribution de chacun au processus de création de valeur, via le processus décisionnel.<br />Nous avons cherché à justifier l'existence des mécanismes de contrôle au sein des universités à partir de l'étude des droits décisionnels et de leur caractère aliénable, qui permettent de définir l'architecture organisationnelle à travers trois dimensions : la répartition des droits décisionnels, le système d'évaluation de la performance, et le système d'incitation. <br />Cette problématique trouve des éléments de réponse à travers quatre études de cas d'universités françaises, qui nous ont permis de tendre vers une généralisation analytique.

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