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- Abbasi, Saeed, 1973-
(författare)
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Towards elimination of airborne particles from rail traffic
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the investigation of wear particles from rail transport started in the late 1910s, the high mass concentrations of these particles have prompted concern among researchers interested in air quality. However, effective action has yet to be taken because relevant knowledge is still missing. This thesis provides knowledge of airborne wear particles originating from rail transport. Some aspects of their characteristic parameters, such as size, mass concentration, number concentration, and morphology, were investigated in the field and in laboratory tests. We also discuss means to mitigate non-exhaust emissions, as well as the advantages and disadvantages of various test set-ups in the seven appended journal papers:Paper A reviews recent studies of exhaust and non-exhaust emissions from rail vehicles. The results, measurements, adverse health effects, and proposed or applied solutions presented in this literature are summarized in this paper.Paper B summarizes the results of field tests we conducted. The effects of curve negotiation and braking under different real conditions were investigated in a field test in which on-board measurements were made. The elemental composition and morphology of the particles emitted and their potential sources were also investigated.Paper C describes how a pin-on-disc machine can be used to reproduce real operating conditions during mechanical train braking in a controlled laboratory setting. The results were validated by comparing the field test results with the results of laboratory studies.Paper D presents comprehensive results of laboratory studies of airborne particles from different braking materials. A new index is introduced in this paper, which can be used as a quantitative metric for assessing airborne wear particle emission rates.Paper E describes the effects of using various friction modifiers and lubricants on the characteristics of airborne particles from wheel–rail contact under lubricated and unlubricated conditions.Paper F reports work to simulate thermoelastic instability in the cast-iron braking material. We simulated the fluctuation of the flash temperature by considering the temperature dependency of the material properties and the transformation of the contact state due to thermomechanical phenomena and wear.Paper G reviews new full- and sub-scale measurements of non-exhaust emissions from ground transport. The advantages and disadvantages of on-board measurements, pin-on-disc tests, dynamometer tests, and test rig studies are discussed in this paper.
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- Adamsson, Niklas, 1977-
(författare)
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Interdisciplinary integration in complex product development : managerial implications of embedding software in manufactured goods
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Incorporating electronics and software systems into manufactured goods is becoming very common in manufacturing companies. New technical functions, increased flexibility, and compensation for mechanical design weaknesses are some key drivers of this technological change in our everyday products. The automotive industry exemplifies this trend, since approximately 80–90% of new functions in cars are based on electronics and software, and it is expected that at least a third of the total cost of a car will eventually be accounted for by electronics and software. However, one of the main downsides of this technological trend is the increasing number of quality issues related to these new technologies, something usually claimed to be a result of the increased product development complexity. Previous research into product development management has mainly concentrated on either physical products or software systems, but not concurrently on both. Additionally, much of the research has concentrated on issues of integrating marketing, R&D, and manufacturing in these companies, and has treated the engineering disciplines in R&D as a homogenous group. Motivated by this change in technology content and the lack of research into complex product development and especially into integration between engineering disciplines, the present work investigates how to increase operational performance in multidisciplinary engineering organizations. This work has especially focused on interdisciplinary integration and the feasibility of various so-called integration mechanisms, such as building common physical facilities, job rotation programs, the implementation and use of information and communications technology, and computer-aided engineering tools. Both qualitative and quantitative research has been performed, involving 11 different companies and over 300 respondents. Supported by the present findings, it is demonstrated that interdisciplinary integration is a crucial factor to consider, and it is concluded that certain integration mechanisms stand out as more important than others. Organizational structure, work procedures and methods, training, social systems, and computer-aided engineering were the five types of mechanisms that displayed the greatest potential for improvement. It is further concluded that the ability to successfully match the body of practices to current products is essential, since there is a high risk of current practices becoming out-dated with respect to the technology content. Furthermore, inadequate identification of or managerial ability to establish the currently most important interfaces complicate the choice of trade-offs between various technologies that are found to be essential to cope with the inherent dynamic complexity. The organizational powerbase is often re-positioned in the studied organizations, and the loss of decisive power can result in a demoralizing ignorance of newly established disciplines and their design practices. Additionally, rigid structures and counterproductive traditions can reduce the potential gains accruing from new boundary-spanning innovations, so organizational responsibilities and mandates must be declared unambiguously, in many cases differently from how they have been in the past. Based on these conclusions, it is suggested that managers in organizations like those studied must be able to do the following: cultivate software knowledge in all parts and levels of the product development organization; reassess their recruitment strategies; organize for interdisciplinary collaboration; articulate and communicate the technology fusion strategy to all disciplines; and realize and disseminate the fact that product launches do not only concern manufacturability.
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- Adamsson, Niklas, 1977-
(författare)
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Mechatronics engineering : New requirements on cross-functional integration
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Several industrial sectors experience an increased reliance on mechatronic systems as electronics and software are being embedded into the traditional mechanical systems of these industries. Important challenges within mechatronics engineering comes from management of multi-disciplinary development project teams and the highly complex scope of problems, which in turn require extensive coordination and integration, both in terms of technical and organisational matters. The concept of cross-functional integration in product development research has in previous research mainly addressed integration of the functions marketing, R&D, and manufacturing, and whereas the present thesis is delimited to include only the R&D organization and the functions and engineering disciplines within such an organization. The purpose with thesis has been to investigate mechatronics engineering in order to understand and explain how co-operation, integration, and knowledge sharing between engineering disciplines can be supported. This research has been realized by empirical studies in mechatronic development settings in engineering companies, but also by taking part in industrial and academic research projects that develop and study computer-aided mechatronics engineering. Findings presented in this thesis show that mechatronics is a matter of integration at three organizational levels where the most substantial needs are found to be at the team-level and the individual level. Furthermore, it is identified that to be able to succeed in mechatronics engineering, managers and engineers must look beyond disciplinary needs. Subsequently, both teamwork and competence management become key issues for management of mechatronics engineering. Finally, computer-supported and model-based development of mechatronics show great potential for successful integration of engineering disciplines, even though such technological aids are still rather immature and needs further research and development. A tentative analysis model of organizational integration for mechatronics engineering is also presented and discussed in this thesis. Based on the presented findings, it is concluded that companies incorporating electronics and software in their mechanical products must effectively manage software and electronics development of these embedded systems. Despite the focus on cross-functional integration in engineering companies, this thesis shows examples of inadequate integration of software and electronics engineering with mechanical integration in organisations dominated by the latter. Future research studies are needed to investigate the relation between factors influencing the need for organizational integration and potential integration mechanisms. To further understand mechatronics engineering it is important to look deeper into research issues such as changed conditions for the engineering profession implied by multidisciplinary settings, social systems supporting integration of disciplines, changed work conditions due to implementation of technological aids for model-based system development, relationship between product and organizational complexity, organizational designs supporting integration of engineering disciplines, and cross-disciplinary training of highly specialized engineers.
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- Aftab, Ahmad, 1979-
(författare)
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Model-based design of haptic devices
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Efficient engineering design and development of high precision and reliable surgical simulators, like haptic devices for surgical training benefits from model-based and simulation driven design. The complexity of the design space, multi-domains, multicriteria requirements and multi-physics character of the behavior of such a product ask for a model based systematic approach for creating and validating compact and computationally efficient simulation models to be used for the design process.The research presented in this thesis describes a model-based design approach towards the design of haptic devices for simulation of surgical procedures, in case of hard tissues such as bone or teeth milling. The proposed approach is applied to a new haptic device based on TAU configuration.The main contributions of this thesis are: Development and verification of kinematic and dynamic models of the TAU haptic device. Multi-objective optimization (MOO) approach for optimum design of the TAU haptic device by optimizing kinematic performance indices, like workspace volume, kinematic isotropy and torque requirement of actuators. A methodology for creating an analytical and compact model of the quasi-static stiffness of haptic devices, which considers the stiffness of; actuation system;flexible links and passive joints.
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- Aghaali, Habib, 1981-
(författare)
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On-Engine Turbocharger Performance Considering Heat Transfer
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Heat transfer plays an important role in affecting an on-engine turbocharger performance. However, it is normally not taken into account for turbocharged engine simulations. Generally, an engine simulation based on one-dimensional gas dynamics uses turbocharger performance maps which are measured without quantifying and qualifying the heat transfer, regardless of the fact that they are measured on the hot-flow or cold-flow gas-stand. Since heat transfer situations vary for on-engine turbochargers, the maps have to be shifted and corrected in the 1-D engine simulation, which mass and efficiency multipliers usually do for both the turbine and the compressor. The multipliers change the maps and are often different for every load point. Particularly, the efficiency multiplier is different for every heat transfer situation on the turbocharger. The heat transfer leads to a deviation from turbocharger performance maps, and increased complexity of the turbocharged engine simulation. Turbochargers operate under different heat transfer situations while they are installed on the engines. The main objectives of this thesis are: heat transfer modeling of a turbocharger to quantify and qualify heat transfer mechanisms, improving turbocharged engine simulation by including heat transfer in the turbocharger, assessing the use of two different turbocharger performance maps concerning the heat transfer situation (cold-measured and hot-measured turbocharger performance maps) in the simulation of a measured turbocharged engine, prediction of turbocharger walls’ temperatures and their effects on the turbocharger performance on different heat transfer situations. Experimental investigation has been performed on a water-oil-cooled turbocharger, which was installed on a 2-liter GDI engine for different load points of the engine and different heat transfer situations on the turbocharger by using insulators, an extra cooling fan, radiation shields and water-cooling settings. In addition, several thermocouples have been used on accessible surfaces of the turbocharger to calculate external heat transfers. Based on the heat transfer analysis of the turbocharger, the internal heat transfer from the bearing housing to the compressor significantly affects the compressor. However, the internal heat transfer from the turbine to the bearing housing and the external heat transfer of the turbine housing mainly influence the turbine. The external heat transfers of the compressor housing and the bearing housing, and the frictional power do not play an important role in the heat transfer analysis of the turbocharger. The effect of the extra cooling fan on the energy balance of the turbocharger is significant. However, the effect of the water is more significant on the external heat transfer of the bearing housing and the internal heat transfer from the bearing housing to the compressor. It seems the radiation shield between the turbine and the compressor has no significant effect on the energy balance of the turbocharger. The present study shows that the heat transfer in the turbocharger is very crucial to take into account in the engine simulations. This improves simulation predictability in terms of getting the compressor efficiency multiplier equal to one and turbine efficiency multiplier closer to one, and achieving turbine outlet temperature close to the measurement. Moreover, the compressor outlet temperature becomes equal to the measurement without correcting the map. The heat transfer situation during the measurement of the turbocharger performance influences the amount of simulated heat flow to the compressor. The heat transfer situation may be defined by the turbine inlet temperature, oil heat flux and water heat flux. However, the heat transfer situation on the turbine makes a difference on the required turbine efficiency multiplier, rather than the amount of turbine heat flow. It seems the turbine heat flow is a stronger function of available energy into the turbine. Of great interest is the fact that different heat situations on the turbocharger do not considerably influence the pressure ratio of the compressor. The turbine and compressor efficiencies are the most important parameters that are affected by that. The component temperatures of the turbocharger influence the working fluid temperatures. Additionally, the turbocharger wall temperatures are predictable from the experiment. This prediction enables increased precision in engine simulations for future works in transient operations.
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