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- Aagerup, Ulf, 1969-
(författare)
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The Impact of User Weight on Brands and Business Practices in Mass Market Fashion
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Overweight people claim to be mistreated by the fashion industry. If they were, it would be in line with branding theory supporting the idea of rejecting fat consumers to improve user imagery for fashion brands. However, fashion companies do not confess to such practices.To shed some light on the subject, I have conducted two studies.The first attempts to illustrate what effect, if any, user imagery has on fashion brands. It is an experiment designed to show how the weight of users affects consumers’ perceptions of mass market fashion brands. The findings show that consumers’ impressions of mass market fashion brands are significantly affected by the weight of its users. The effect of male user imagery is ambiguous. For women’s fashion on the other hand, slender users are to be preferred.In the second study I examine what effects these effects have on assortments. I compare the sizes of mass market clothes to the body sizes of the population. No evidence of discrimination of overweight or obese consumers was found -quite the contrary.The reasons for these unexpected findings may be explained by the requirements a brand must fulfil to make management of the customer base for user imagery purposes viable. The brand must be sensitive to user imagery; a requirement that mass market fashion fulfils. However, it must also be feasible for a company to exclude customers, and while garment sizes can be restricted to achieve this, the high volume sales strategy of mass market fashion apparently cannot.
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| 3. |
- Abbasi, Saeed
(författare)
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Characterisation of airborne particles from rail traffic
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the investigation of wear particles in rail transport started in late-1910s, the high mass concentration of these particles has raised worries among researchers concerned with air quality. However, effective action has yet to be taken because of lack of relevant knowledge. This thesis provides applicable information for the airborne wear particles in rail transport. Some aspects of their characteristics such as diameter size, mass concentration, number concentration, and morphology of particles were investigated in field tests and laboratory tests.The effects on particle characterisations from different operational conditions in the field tests, and applying different braking materials, conducting tests in different applied loads or sliding velocities in the laboratory tests were studied. The main advantage of conducting laboratory tests was to focus on studying particles from one source. The possibility of repetition, using high sensitive instruments and conducting tests at low costs are the other advantages of laboratory studies. Paper A describes how a pin-on-disc machine was used to reproduce similar real operational conditions during mechanical braking in a train. The results were validated by comparing the field tests results with the laboratory studies. The particles morphology and size distribution were also studied.Paper B presents a summary of field tests results. The effects of curve negotiating and applying braking in different real conditions were investigated with an on-board measurement.The element composition of the particles and their potential sources were also investigated outside of the particles morphologies.Paper C presents comprehensive results from laboratory studies on airborne particles from different braking materials. The differences in the particle characteristics in similar test conditions were attributable to different material compositions and dominant wear mechanisms. A new index was introduced in this paper and is suggested to be used as a qualitative factor with regard to the airborne wear particle emission rate.Paper D is a review of the recent studies of exhaust emission and non-exhaust emission from rail vehicles. A summary of results, measurements, adverse health effects, and proposed or applied solutions are reviewed in this paper.
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| 5. |
- Abdullah Asif, Farazee Mohammad, 1980-
(författare)
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Resource Conservative Manufacturing : New Generation of Manufacturing
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The question of resource scarcity and emerging pressure of environmentallegislations have put the manufacturing industry with a new challenge. On theone side, there is a huge population that demands a large quantity ofcommodities, on the other side, these demands have to be met by minimumresources and with permissible pollution that the earth’s ecosystem can handle.In this situation, technologic breakthrough that can offer alternative resourceshas become essential. Unfortunately, breakthroughs do not follow any rule ofthumb and while waiting for a miracle, the manufacturing industry has to findways to conserve resources. Within this research the anatomy of a large body ofknowledge has been performed to find the best available practices for resourceconservation. Critical review of the research revealed that none of the availablesolutions are compatible with the level of resource conservation desired by themanufacturing industry or by society. It has also been discovered that a largegap exists between the solutions perceived by the scientists and theapplicability of those solutions. Through careful evaluation of the state-of-theart,the research presented in this thesis introduced a solution of maximizingresource conservation i.e., material, energy and value added, as used inmanufacturing. The solutions emerged from the novel concept named asResource Conservative Manufacturing, which is built upon the concept ofMultiple Lifecycle of product. Unlike other research work, the researchdocumented in this thesis started with the identification of the problem andfrom which a ‘wish to do’ list was drawn. The seriousness of the problem andpotential of adopting the proposed concept has been justified with concreteinformation. A great number of arguments have been presented to show theexisting gaps in the research and from that, a set of solutions to conserveresources has been proposed. Finally, one of the prime hypotheses concerningclosed loop supply chain has been validated through the system dynamicsmodeling and simulation.
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| 6. |
- Abidin, Aysajan
(författare)
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Weaknesses of Authentication in Quantum Cryptography and Strongly Universal Hash Functions
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Authentication is an indispensable part of Quantum Cryptography, which is an unconditionally secure key distribution technique based on the laws of nature. Without proper authentication, Quantum Cryptography is vulnerable to “man-in-the-middle” attacks. Therefore, to guarantee unconditional security of any Quantum Cryptographic protocols, the authentication used must also be unconditionally secure. The standard in Quantum Cryptography is to use theWegman-Carter authentication, which is unconditionally secure and is based on the idea of universal hashing.In this thesis, we first investigate properties of a Strongly Universal hash function family to facilitate understanding the properties of (classical) authentication used in Quantum Cryptography. Then, we study vulnerabilities of a recently proposed authentication protocol intended to rule out a "man-in-the-middle" attack on Quantum Cryptography. Here, we point out that the proposed authentication primitive is not secure when used in a generic Quantum Cryptographic protocol. Lastly, we estimate the lifetime of authentication using encrypted tags when the encryption key is partially known. Under simplifying assumptions, we derive that the lifetime is linearly dependent on the length of the authentication key. Experimental results that support the theoretical results are also presented.
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| 7. |
- Abou-Taouk, Abdallah, 1982
(författare)
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CFD Modeling of Combustion in Flexi-Fuel Burners at Gas Turbine Conditions
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main source of energy in the nearest future will come from fossil fuels. Increasing demands on environmentally friendly energy conversion implies that pollutants, such as CO and NOx, need to be reduced. This project aims to investigate recent developments in combustion modeling and turbulence modeling in the context of engineering type Computational Fluid Dynamics (CFD) analysis tools, applied to the main problem area of swirl-stabilized flexi-fuel flames. To perform a CFD simulation of reacting flows, kinetic information needs to be provided to the CFD code. Fully detailed kinetic mechanisms are expensive in terms of computer time when coupled with CFD and hence the use of global reaction mechanisms is preferable. Global mechanismsconsist of a reduced number of reactions mostly one-way reactions which are governed by tuned Arrhenius rate expressions. The optimization at each equivalence ratio is here done by comparing results from Perfectly Stirred Reactor (PSR) calculations for both a detailed reference mechanism and the chosen multi-step global reaction mechanisms.Steady-state Reynolds Averaged Navier Stokes (RANS), hybrid Unsteady RANS/Large Eddy Simulation (URANS/LES) and LES turbulence models have been used in the CFD work. This thesis includes the development and derivation of new 3-step global reaction mechanism for methane-air flames, which has been implemented and evaluated in the CFD analysis for two different burner configurations. In papers I and II an atmospheric burner test rig at Lund University (LTH) has been modeled and the results have been compared to high quality experimental data (emission and Particle Image Velocimetry (PIV) data). There is good agreement between the CFD simulations and measurements of emissions, velocity field and flame visualization. The second configuration that has been modeled and compared with experimental data is the Sandia Flame D test case, which is reported in paper III.Keywords: CFD, Chemistry, Combustion, RANS, LES, SAS-SST, PSR, Global reaction mechanism
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| 8. |
- Abrahamsson, Johan
(författare)
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Kinetic Energy Storage and Magnetic Bearings, for vehicular applications
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the main challenges in order to make electric cars competitive with gaspowered cars is in the improvement of the electric power system. Although many of the energy sources currently used in electric vehicles have sufficiently high specific energy, their applicability is limited due to low specific power. It would therefore be advantageous to create a driveline with the main energy storage separated from a smaller energy buffer, designed to have high power capabilities and to withstand frequent and deep discharge cycles. It has been found that rotating kinetic energy storage in flywheels is very well suited for this type of application. The work presented in this thesis and the included papers span a number of topcis Introductory overview - This section explains the concept of the modern flywheel, and investigates some of its properties. It illustrates the concepts with a number of examples, relevant for the usage of flywheels in vehicular applications. Experimental set-up - The construction of a complete electric driveline is ongoing within the division for Electricity at Uppsala University. An optimized electric machine has been constructed and connected with a programmable load, as well as with a DC power source through power electronics controlled by PWM. As a part of this system, an experimental set-up of an active magnetic bearing for two degrees-of-freedom has been constructed. The work with this device is described in detail and some preliminary results are presented. Self-bearing machine - The electric machine developed for the existing driveline is coreless, double wound and with a double rotor. In order to achieve magnetic bearing functionality in this device for all DOF, a novel Lorentz force self-bearing machine is suggested. The design is analyzed analytically and numerically.
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| 10. |
- Acuña, José, 1982-
(författare)
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Improvements of U-pipe Borehole Heat Exchangers
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The sales of Ground Source Heat Pumps in Sweden and many other countries are having a rapid growth in the last decade. Today, there are approximately 360 000 systems installed in Sweden, with a growing rate of about 30 000 installations per year. The most common way to exchange heat with the bedrock in ground source heat pump applications is circulating a secondary fluid through a Borehole Heat Exchanger (BHE), a closed loop in a vertical borehole. The fluid transports the heat from the ground to a certain heating and/or cooling application. A fluid with one degree higher or lower temperature coming out from the borehole may represent a 2-3% change in the COP of a heat pump system. It is therefore of great relevance to design cost effective and easy to install borehole heat exchangers. U-pipe BHEs consisting of two equal cylindrical pipes connected together at the borehole bottom have dominated the market for several years in spite of their relatively poor thermal performance and, still, there exist many uncertainties about how to optimize them. Although more efficient BHEs have been discussed for many years, the introduction of new designs has been practically lacking. However, the interest for innovation within this field is increasing nowadays and more effective methods for injecting or extracting heat into/from the ground (better BHEs) with smaller temperature differences between the heat secondary fluid and the surrounding bedrock must be suggested for introduction into the market.This report presents the analysis of several groundwater filled borehole heat exchangers, including standard and alternative U-pipe configurations (e.g. with spacers, grooves), as well as two coaxial designs. The study embraces measurements of borehole deviation, ground water flow, undisturbed ground temperature profile, secondary fluid and groundwater temperature variations in time, theoretical analyses with a FEM software, Distributed Thermal Response Test (DTRT), and pressure drop. Significant attention is devoted to distributed temperature measurements using optic fiber cables along the BHEs during heat extraction and heat injection from and to the ground.
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