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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.
101

DRIVING SIMULATION AND REACTION TIME INVESTIGATION ON DRIVER FOOTEDNESS

Ali, Ahmed M. 29 August 2019 (has links)
No description available.
102

Establishment of an action plan for better recovery of building waste from demolition and rehabilitation operations

Miralles, Louis January 2020 (has links)
The aim of this study was to establish an action plan whose implementation would improve waste management practices in demolition and rehabilitation operations and improve the recovery of waste from these operations in accordance with the hierarchy established by the European regulations in the Waste Framework Directive of 19 November 2008. This study made it possible to establish a diagnosis of the current state of waste management in the building sector and to identify the various brakes preventing better waste recovery. For these brakes, levers for improvement were identified by a literature study, associated with concrete examples of innovative solutions implemented by companies in France. A systemic approach to the building sector was used to identify the brakes and levers for improvement. This macroscopic approach took into consideration all the players in the sector as well as all the phases (upstream and downstream) of a demolition or rehabilitation project. On the basis of the brakes and levers identified, graphs representing the causal links between the brakes and the levers of improvement were drawn up. The superimposition of these graphs made it possible to draw up brake-lever pairs, which together forms the basis for the action plan for improving waste recovery. Being limited to demolition and rehabilitation operations only, the method carried out in this study may also be used in future studies applying this protocol to the entire building sector including also infrastructures. The action plan established in this study could thereby be enriched. The second step will be to put the action plan into practice on a "test" work site and to study the impact of the improvement levers on waste recovery in order to conclude on the relevance of this action plan.
103

A fundamental study on the heat partition ratio of vehicle disc brakes

Loizou, Andreas, Qi, Hong Sheng, Day, Andrew J. January 2013 (has links)
no / The interface tribo-layer (ITL) in an automotive brake friction pair is a layer of material created from transfer films, wear particles, and surface transformations between the rotor and stator. Its presence in a brake friction interface has been proven, e.g. by the existence of a temperature ‘jump’ across the friction interface. In this paper two static transient heat transfer models which force one dimensional heat flow, have been used to investigate the ITL behaviour and obtain an equivalent thermal conductance value. The ITL equivalent thermal conductance value is important as it reduces computational requirements and software restrictions encountered in the physical model of the ITL. This approach is developed into a more realistic two-dimensional coupled temperature-displacement model using commercial FEA software (ABAQUS). A newly developed relationship that utilises the contact pressure, real contact area, and the ITL equivalent thermal conductance, has been used to estimate the effective thermal conductance at the friction interface. Subsequently the effective thermal conductance relationship is combined with the 2-D coupled temperaturedisplacement model. The combination of this relationship with the 2D FE model provides a new method of heat partition prediction in brake friction pairs. Heat partition at a brake friction interface is confirmed to be neither uniform nor constant with time. / IMechE / The full text will not be made available in Bradford Scholars due to the publisher's copyright policies.
104

Towards Sustainable Braking: Effects of Alternative Ingredients on the Tribological Properties of Friction Materials

Carlevaris, Davide 26 July 2024 (has links)
The most important safety device for commercial vehicles is the brake system. It has to satisfy multiple requirements such as braking performance, wear resistance and low noise production. In the last years, a further requirement has been gaining increasing attention: their particulate matter emission. Indeed, brake systems are one of the most relevant sources of non-exhaust traffic-related emission PM. These emissions have been shown to negatively affect both the environment and the human health, urging authorities to take legislative action. This work is focused on improving the sustainability aspects of brake friction materials. This was done by following two different approaches, both of which involved the use of alternative ingredients in the friction material composition. The new ingredients were chosen based on their properties while also considering aspects related to an eventual industrial application. The first approach involved the use of a natural ingredient, rice husk, as an ingredient in the composition of friction materials; whereas the second approach dealt with the substitution of the conventional phenolic resin binder with benzoxazine resins. The tribological and PM emission properties of friction material samples produced using these ingredients were investigated via tribological testing, and were correlated to the results of the characterization analyses that were performed on the worn surfaces, on the collected emitted particles, and on the newly adopted ingredients themselves. Rice husk is a widely available byproduct of the agricultural industry, and possesses some peculiar properties related to its considerable inorganic content that separates it from the other lignocellulosic materials. Friction materials modified with rice husk were tested with a Pin-on-Disc tribometer and with a reduced-scale dynamometric bench while also monitoring their PM emission. Overall, the adoption of rice husk showed promising results, preserving the friction material coefficient of friction, PM emission and wear resistance. However, when higher temperatures were reached, a loss of performance and durability was observed. Nevertheless, this temperature range was above that associated to common LDV brake system operation, which this application is targeted to. Benzoxazine resins are a relatively new class of binders that display some attractive properties when compared to the conventionally used phenolic resins, such as more forgiving storage conditions, improved thermal stability and customizability of their properties. Two of the simplest representatives of the benzoxazine resin family were hereby adopted. An initial characterization of the thermal behaviour of the resins was first carried out to design the production process of the friction materials containing them. Friction materials bound by benzoxazine resins and by a commercial phenolic resin were tested by Pin-on-Disc and reduced-scale dynamometric bench testing while monitoring their PM emission production. The substitution of phenolic resin with benzoxazine resin as friction material binder proved to be successful, leading to lower wear of the samples, which would translate to a lower environmental impact.
105

Vers un contrôle de gestion supply chain intra et inter-organisationnel : l'apport du levier interactif et de la régulation conjointe / Towards intra and inter-organizational supply chain management control : the contribution of interactive lever and joint regulation

Kartit, Imane El 08 October 2018 (has links)
Dans la littérature en contrôle de gestion, plusieurs chercheurs ont exprimé le besoin d’attribuer plus d’attention à l’intégration des problématiques inter-organisationnelles dans l’étude des systèmes de contrôle de gestion depuis l’émergence des nouvelles formes d’organisations qualifiées d’hybrides, de réseaux, ou encore de supply chains. Cette recherche doctorale, de nature exploratoire, consiste donc à étudier le contrôle de gestion supply chain selon une double perspective intra et inter-organisationnelle. Au travers un mode de raisonnement abductif et une méthodologie de recherche qualitative réalisée en trois temps (analyse des descriptifs de profils de 50 contrôleurs de gestion supply chain repérés sur LinkedIn et Viadeo ; 7 entretiens d’experts ; et 19 entretiens semi-directifs avec des informateurs clés), nous proposons une définition du contrôle de gestion supply chain et présentons ses dimensions, ses enjeux, ses axes, ses outils et son périmètre de pilotage. Des facteurs, freins et facilitateurs à sa mise en place, sont aussi repérés. Ils sont regroupés en quatre catégories : intra-organisationnels, inter-organisationnels, techniques/technologiques et humains. Enfin, nous étudions sa dimension interactive à la lumière du levier interactif (Simons, 1995) et la régulation conjointe (Reynaud, 1996) / In the management control literature, several researchers have expressed the need to pay more attention to the integration of inter-organizational issues into the study of management control systems since the emergence of new forms of organization. qualified as hybrids, networks, or even supply chains. This doctoral research, of an exploratory nature, consists in studying supply chain management control from a dual intra and inter-organizational perspective. Through a mode of abductive reasoning and a qualitative research methodology carried out in three stages (analysis of profiles of 50 supply chain management controllers identified on LinkedIn and Viadeo, 7 expert interviews and 19 semi-structured interviews with key informants), we propose a definition of supply chain management control and present its dimensions, its stakes, its axes, its tools and its scope of management. Factors, brakes and facilitators to its implementation, are also identified. They are grouped into four categories: intra-organizational, inter-organizational, technical / technological and human. Finally, we study its interactive dimension in the light of the interactive lever (Simons, 1995) and the joint regulation (Reynaud, 1996).
106

Analyse de l'échec des innovations dans un marché en émergence : approche intégratrice aux niveaux individuel et collectif / To what extent an inclusive approach in marketing work and sociology of innovation, combining the individual and collective levels, it captures the resistance to the construction of a new solution in an emerging market ?

Mokaddem, Sarra 16 June 2016 (has links)
Dans le cadre de nos études doctorales, nous avons travaillé au sein d'une école d'ingénierie de renom qui a développé un partenariat avec l'entreprise Ecoway, en vue du développement de l'innovation de service Movin'out. Adressée aux particuliers (BtoC), aux entreprises, aux opérateurs et aux collectivités (BtoB), cette innovation se présente sous la forme d'une plateforme comunautaire d'écomobilité, visant à inciter les individus à adopter des modes de déplacement vertueux, et donc alternatifs à l'utilisation individuelle de la voiture. Malencontreusement, l'innovation de service responsable Movin'out n'a pas rencontrer le succès attendu pendant notre présence sur le terrain de recherche, et a été rejetée par les adopteurs potentiels sans générer l'effet communautaire.Malgré la richesse de la littérature sur la diffusion et l'adoption des innovations, celle-ci reste fragmentée. En effet, différentes approches ont vu le jour à la croisée de plusieurs disciplines. Ainsi, pour répondre à la question centrale de cette thèse et pour inscrire nos travaux dans le champ théorique du marketing de l'innovation, nous nous sommes premièrement concentrés sur l'approche linéaire développée par Rogers (2003) pour une analyse au niveau des individus, ainsi que sur les travaux sur les communautés virtuelles (Rheingold, 1993; Kozinets, 1999, 2002, 2010), pour une analyse au niveau collectif de l'innovation. Toutefois, ces approches, ne tenant pas compte de l'environnement social de l'individu et des interactions qu'il peut avoir avec l'objet (l'innovation) et les autres individus (les réseaux), nous les complétons avec les travaux en sociologie de l'innovation pour souligner l'importance des interactions dans les réseaux pour la construction réussie d'une innovation.Nous constatons que chaque approche théorique prise séparément en se focalisant sur un niveau d'analyse, que ce soit l'acteur individuel ou collectif, ne peut offrir une vision d'ensemble de la diffusion et de l'adoption des innovations. Aussi, notre objectif est de proposer une approche intégratrice à la croisée du marketing et de la sociologie de l'innovation afin d'analyser la construction échouée d'une innovation de service responsable en train de se faire, sur un marché en émergence, celui de l'écomobilité. L'approche intégratrice se situe ainsi à différents niveaux d'observation : l'individu, la communauté, le réseau. Le parti pris de cette thèse est d'articuler ces niveaux afin d'identifier et d'analyser les comportements de résistance aux innovations de services responsables. Notre contribution se situe dans la mobilisation de cette approche intégratrice pour étudier un sujet peu traité dans la littérature : l'échec d'une innovation. / As part of our doctoral studies, we worked in an engineering school that has developed a partnership with the company Ecoway , for the development of Movin'out service innovation. Addressed to individuals ( BtoC ) , enterprises , service providers and communities ( BtoB) , this innovation comes in the form of a Community eco-mobility platform , to encourage individuals to adopt virtuous modes of transport , and therefore alternative to individual car use . Unfortunately, Movin'out responsible for innovation does not meet the expected success for our presence in the search field and was rejected by potential adopters without generating the communautary effect.Despite the wealth of literature on the diffusion and adoption of innovations, it remains fragmented. Indeed, different approaches have emerged at the crossroads of several disciplines (economics, sociology, management, psychology, etc.) (Masson, Weil and Hatchuel, 2006). So, to answer the central question of this thesis and to register our work in the theoretical field of marketing innovation, we primarily focused on the linear approach developed by Rogers (2003) for an analysis at the individual level as well as work on virtual communities (Rheingold, 1993; Kozinets, 1999, 2002, 2010) for a discussion at the collective level of innovation. However, these approaches, disregarding the social environment of the individual and the interactions it may have with the object (innovation) and other individuals (networks), we complete the work sociology of innovation to emphasize the importance of interaction in networks for the successful construction of innovation.We find that every theoretical approach taken separately by focusing on a level of analysis, whether individual or collective actor, can provide an overall view of the diffusion and adoption of innovations. Also, our goal is to provide an integrative approach at the crossroads of marketing and sociology of innovation to analyze the failed construction of a responsible service innovation in the making, on an emerging market, the ecomobility. The integrative approach is thus situated at different levels of observation: the individual, the community, the network. The bias of this thesis is to articulate these in order to identify and analyze the behavior of resistance to innovations. Our contribution lies in the mobilization of this inclusive approach to study a little treated in the literature about: the failure of an innovation.
107

Particle emissions from car brakes : The influence of contact conditions on the pad-to-rotor interface

Alemani, Mattia January 2017 (has links)
Due to their adverse health effects emissions have been regulated for over three decades. Brake wear particulate matter is the most important non-exhaust source, however current knowledge is mainly limited to observational studies. This thesis aims to investigate relations between the brake system contact conditions and the related emissions on a model scale; validate the results on a component level; and understand to what extent they are significant on a full-scale. Paper A investigates the influence of nominal contact pressure on a model scale. Results show that higher pressure corresponds to higher emissions Paper B investigates the influence of the nominal contact pressure, for different friction materials, on a model scale. A temperature threshold, responsible for a relevant emission increase, is identified. Paper C investigates particle characteristics and wear mechanisms for different nominal contact pressures, on a model scale. Results show an enhanced tribo-layer at higher pressure levels. Paper D investigates the influence of brake system conditions on emissions, on a model scale. Results show that frictional power is the most important parameter. A transition temperature independent of the contact condition is identified. Paper E investigates similarities occurring on a component scale and a model scale in terms of emissions. Results show a promising correlation, and the possibility of using a pin-on-disc tribometer for R&amp;D activities. Paper F investigates analogies occurring on a component scale and a model scale, in terms of friction performance, fictional surface and chemical composition. Results show similar phenomena occurring for the two test stands. Paper G analyses real brake system working conditions in a urban environment defining, by means of an inertia dyno bench, the related emissions. Results reveal emission factors compliant to EURO6 and EURO2 regulations, in terms of number and mass, respectively. / På grund av deras negativa hälsoeffekter har partikel emissioner reglerats i över tre årtionden. Bromsslitagepartiklar är den viktigaste icke-avgaskällan, men nuvarande kunskaper är huvudsakligen begränsade till observationsstudier. Avhandlingen syftar till att undersöka förhållandena mellan bromssystemets kontaktförhållanden och de relaterade utsläppen på modellskala. Validera resultaten på komponentnivå och förstå i vilken utsträckning de är betydande i full skala. Papper A undersöker påverkan av nominellt kontakttryck i en modellskala. Resultat visar att högre tryck motsvarar högre utsläpp. Papper B undersöker påverkan av det nominella kontakttrycket, för olika friktionsmaterial, i modellskala. En temperaturtröskel,  för en emissionsökning identifieras. Papper C undersöker partikelegenskaper och slitagemekanismer för olika nominella kontakttryck, i en modellskala. Resultat visar ett förbättrat triboskikt vid högre trycknivåer. Papper D undersöker påverkan av bromssystemets förhållanden på utsläpp i en modellskala. Resultat visar att friktionskraften är den viktigaste parametern. En övergångstemperatur oberoende av kontaktförhållandet identifieras. Papper E undersöker likheter som uppträder på komponentskala och  modellskala när det gäller emissioner. Resultatet visar en lovande korrelation, och möjligheten att använda en pinne-på-skiva-tribometer för FoU-aktiviteter. Papper F undersöker analogier som förekommer på en komponentskala och en modellskala, vad gäller friktionsprestanda, friktionsyta och kemisk sammansättning. Resultat visar liknande fenomen som förekommer för de två testskalorna. Papper G analyserar verkliga bromssystem arbetsförhållanden i en stadsmiljö som definierar, med hjälp av en tröghetsdyno bänk, de relaterade utsläppen. Resultatet visar utsläppsfaktorer som är förenliga med EURO6 och EURO2-reglerna, i fråga om antal respektive massa. / <p>QC 20170808</p> / REBRAKE Project
108

Trådbromssystem : En fallstudie för implementering av bromssystem i en lindningsprocess

Östman, Fredrik, Melin, Philip January 2021 (has links)
For an energy efficient current transmission, high demands are set on the construction of transformers. One of the more significant parts is the winding that constitutes the core of the transformer. In order to secure a high quality and reduced loss of energy, companies therefore work actively with decreasing possible sources of error in order to gain better control over the processes.The thesis is an investigative feasibility study with the purpose to examine the possibility to implement amore reliable brake system in a wire winding process aswell as creating documents with possible solutions for how the feeding of wire can be controlled.In the study are first and foremost qualitative methods for data collection used. These partly consist of an interview study with employees, observations from the industry and a literature review aswell as a market study. The methods are chosen to give a broad description of how the process function and what other solutions can be applicable to be used in a final conceptual solution proposal.From the interview study, the needs and requirements were summarized into a list of selection criterias. These criterias were weighted and then used to select one of the concepts for further development. The final solution presented two different proposals for brake types depending on whether the company wants to use a pneumatic or electric brake system. Further in the development, suggestions are given on how the brakes could be controlled. The aim of this point is to be able to create a higher reliability in the regulation of the system's brake pressure and allow the operator to do this from the front of the workstation. / För en energieffektiv strömöverföring ställs det höga krav på konstruktionen av transformatorer. En betydelsefull faktor är de lindningar som utgör kärnan på transformatorn. För att kunna säkerställa en hög kvalitet och minskad energiförlust arbetar företagen aktivt med att minimera möjliga felkällor för att få bättre kontroll över processerna.Rapporten har strukturen av en undersökande förstudie där syftet är att undersöka möjligheten att implementera ett mer pålitligt bromssystem i en trådlindningsprocess samt skapa underlag för möjliga lösningar över hur trådmatningen kan regleras.Som grund används framför allt kvalitativa datainsamlingsmetoder. Dessa utgörs dels av en intervjustudie med anställda, observationer av verksamheten och processen, dels en litteratur- ochmarknadsundersökning. Metoderna används för att få en bred uppfattning av den process som undersöks samt vilka andra lösningar som kan vara tillämpbara för att slutligen användas som underlag till konceptuella lösningsförslag.Från intervjustudien sammanfattade de behov och krav som finns till en lista med urvalskriterier. Dessa kriterier viktades varpå de användes för att välja ett av koncepten för vidare utveckling och förtydligande. I det slutgiltiga lösningsförslaget presenterades två olika förslag på bromstyper beroende på om företaget vill utnyttja ett pneumatiskt eller elektriskt bromssystem. I nästa steg av utvecklingen ges förslag på hur styrning av bromsarna skulle kunna ske. Målet med denna punkt är kunna skapa en högre pålitlighet i regleringen av systemets bromstryck samt tillåta operatören att göra detta framifrån arbetsstationen.
109

Konstrukce čtyřkolky (ATV) s elektrickým pohonem / Design of all-terrain vehicle with electric drive

Kučera, Pavel January 2011 (has links)
This master's thesis describes the design of All-Terrain Vehicle (ATV) with electric drive. The design is focused on the main parts of the ATV, which are designed with modern trends ATVs. Location of electric drive and batteries in the frame of the ATV is solved for the sport version of the ATV. Steering geometry is designed using the program Adams. For models of main components are created stress analysis in Ansys Workbench. The input is 3D model, which is created in Pro/Engineer. The braking system and wheels are designed for movement and braking of the terrain.
110

Analýza zpomalování trolejbusů a vyhodnocení jeho účinků na stojící cestující / Analysis of Deceleration of Trolleybuses and Evaluation of its Impact on Standing Passengers

Semmler, Petr January 2012 (has links)
This thesis is focused on analysis and evaluation of the trolley deceleration effect on his standing passengers. The first part focuses on theoretical knowledge in terms of legislative requirements for the operation of trolleybuses and transport standing passengers. This section also lists physical findings during deceleration and forces acting on the vehicle. The central part is divided into two measurements. The first measure is aimed at obtaining data (deceleration) and information (number of passengers, increased stability, and fall) of the normal operation of the standing passengers in interior trolley. The second measurement will be focused on driving performance demonstration tests with the interior trolley helpers in various traffic situations. The conclusion of this thesis will summarize the values and knowledge of both measurements. The evaluated data set will limit the slowdown in the trolley passengers where standing still maintains stability.

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