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Since the dawn of space exploration, material outgassing has been a major concern when developing a spacecraft. This has not only led to the creation of clean-rooms, but also to the development of various testing methods and standards used to understand the outgassing characteristics of any given material. In industry, low-outgassing materials are used to prevent contamination of electronics and camera lenses, because outgassed contaminates can lead to electronic failure and blurry images. The objective of this study is to develop a gas sensing sensor data acquisition system comprised of inexpensive commercial off-the-shelf components capable of detecting acceleration, atmospheric characteristics, and gas concentrations. Ground tests have been conducted to determine baseline characteristics of the components and develop an understanding of the CO2, CO and NO2 sensors’ ability to detect outgassing from PLA and ABS. Significant CO2 outgassing from PLA and ABS was observed, while CO outgassing was highly temperature dependent.

Three decades ago, the first securitization product was introduced to the investing public in the United States by federal agencies and similar products showed up in Taiwan in 2002. It is a brand new concept for investors in Taiwan and material differences between the west and the east should be considered thoroughly. This research focus on must-knows and critical techniques of securitization of credit card receivables in Taiwan. The researcher discovered that, the competitiveness of originators is one crucial factor for credit card securitization to survive during serious conditions. Without the ability to refill declining credit card receivables in asset pool of securitization transactions, early amortization will be triggered and that’s where case closed. Cash flow forecasting model is another important player in credit card securitization. By predicting future cash flows needed and generated, originators can reap the most profit. However, the variables in this magic model are not easy to find. Through multiple analyses and one simulated case, the researcher found that the most important factors are yield rate, loss rate, repurchase rate, and monthly payment rate. / Three decades ago, the first securitization product was introduced to the investing public in the United States by federal agencies and similar products showed up in Taiwan in 2002. It is a brand new concept for investors in Taiwan and material differences between the west and the east should be considered thoroughly. This research focus on must-knows and critical techniques of securitization of credit card receivables in Taiwan. The researcher discovered that, the competitiveness of originators is one crucial factor for credit card securitization to survive during serious conditions. Without the ability to refill declining credit card receivables in asset pool of securitization transactions, early amortization will be triggered and that’s where case closed. Cash flow forecasting model is another important player in credit card securitization. By predicting future cash flows needed and generated, originators can reap the most profit. However, the variables in this magic model are not easy to find. Through multiple analyses and one simulated case, the researcher found that the most important factors are yield rate, loss rate, repurchase rate, and monthly payment rate.

The number of elderly people has been steadily rising in Sweden for a long time and as a proportion of the population, the increase has been even greater. The population structure in the country means that in the not too distant future, there will be a sharp rise in demand for care and elderly accommodation. A tighter credit market as a consequence of new rules and regulations with a stricter capital and liquidity requirements combined with market turbulence, has made financing property developement more difficult and more expensive which has resulted in many companies using alternative sources of finance. DEmand for safe investments with low risk is high as the market is volatile and banks, pension funds, fund management and life insurance companies are looking for investments outside the stock market that can deliver a safe return in the longer term. There has also been a debate about whether institutional investors as the AP pension funds really should own properties directly. As properties for care and elderly accommodation are definable assets with predictable payment flows, long leases and often a local authority as tenant that would not risk cancelling payments, these would be highly appropriate for securitisation, i.e. to issue bonds or other tradable securities based on the cash flows from the assets. In other words, the securitisation of rent flows would offer the opportunity to create an attractive investment product of the type being demanded, well suited to institutional investor requirements, while at the same time, it can provide an attractive financing opportunity to meet the need for more care and elderly accommodation.

En stor del av fastighetskrediterna på den svenska fastighetsmarknaden kommer under de närmsta åren att refinansieras. Detta i kombination med striktare kapital- och likviditetskrav samt riskkontroll, innebär att fastighetsinvesterare kommer att söka sig till kapitalmarknaden för alternativa finansieringskällor. Detta öppnar upp för värdepapperisering av fastigheters hyresflöden som ett intressant finansieringsalternativ. Värdepapperisering är ett förfarande som innebär att relativt homogena tillgångar eller fordringar med förutsägbara betalningsflöden överlåtes till ett Special Purpose Vehicle (SPV) vars enda uppgift är att äga tillgångarna eller fordringarna. Förvärvet finansieras genom att SPV:n emitterar obligationer eller andra lätt omsättningsbara värdepapper som placeras hos investerare. I princip alla typer av fordringar kan värdepapperiseras som exempelvis kreditkortsskulder och billån, men värdepapperisering av fastighetslån är det vanligaste. I Sverige har det till dags dato endast genomförts två värdepapperiseringar med fastigheters hyresflöden som underliggande tillgång. Den mest utmärkande av dessa får anses vara Fysikcentrum i Stockholm, vilket innefattade en emission av obligationer till ett värde om totalt 1,7 miljarder kronor. I och med den ökade efterfrågan på såväl investerings- samt finansieringsalternativ i kombination med stramare regelverk, som Basel III, bör intresset för denna typ av värdepapperisering öka. Exemplet Fysikcentrum tyder på att värdepapperiseringar av fastigheters hyresflöden lämpar sig väl vid nybyggnadsprojekt där ett stabilt hyresflöde kan säkerställas genom en långsiktig och säker aktör, såsom en statlig eller kommunal hyresgäst. Värdepapperisering av detta slag är förenliga med en rad potentiella fördelar, såsom effektivare prissättning av risker samt lägre finansieringskostnader i förhållande till traditionella finansieringsalternativ. Då det rör sig om ett komplext finansiellt instrument bör det dock poängteras att kunskapskravet bör vara väl uppfyllt. Slutligen får värdepapperisering, i tider med skillnader i prissättning av fastigheter mellan kapital- och fastighetsmarknad, anses vara en fördelaktig metod för att avyttra fastigheter. Detta kan motiveras med anledning av den arbitragemöjlighet som uppstår p.g.a. skillnaden i prissättning hos de olika marknaderna.

This work focuses on car braking systems. The theoretical part describes types of brakes used in vehicles, construction parameters of drum and disc brakes. This work also describes the electronic system ABS and possibilities of its braking effects on cylinder and platform braking test rooms. Practical part of this diploma thesis focuses on measuring of the braking forces of Škoda Superb in time. The measurement was performed with both active and inactive systém ABS. The results where compared with the braking results of a Volkswagen Golf Variant. Amount of force and decceleration in time measured were used for results evaluation. Results show that the systém ABS has a significant effect on braking. The length of braking is increased, but the car keeps its maneuverability.

In this work, fatigue experiments and observations are used to experimentally and computationally quantify fatigue structure-property relationships and then capture these effects through a microstructure-based MultiStage Fatigue (MSF) model for a thermoplastic Acrylonitrile Butadiene Styrene copolymer. Completely reversed fatigue experiments were conducted over a range of strain amplitudes at two frequencies (1 Hz and 10 Hz). Scanning electron microscopy of fatigue fracture surfaces was used to quantify the microstructural notch root or initiating particle size for structure-property relations. Results were then processed in an MSF model sensitive to microstructural effects to capture the fatigue lifetimes for the thermoplastic ABS copolymer.

No description available.

Tires play an extremely important role in the operation of a vehicle as they transmit forces between the ground and the vehicle. Consistent efforts have been made over the years towards modeling and simulation of tires and more recently, there has been an increasing need to understand the transient response of tires to various high-frequency events such as anti-lock braking and short-wavelength disturbances from the road. Major thrust has been provided by the tire industry to develop simulation models that accurately predict the dynamic response of tires without the use of computationally intensive tools such as FEA. The objective of this research is to explain the development, implementation and validation of a simulation tool based on a dynamic tire model that would assist in the analysis of the effect of tire belt vibrations on the braking performance of a vehicle. A rigid ring tire model, tandem elliptical cam enveloping model and a rule-based ABS model have been developed for this purpose. These were combined together in a quarter vehicle model and implemented in Matlab-Simulink. These models were developed for adaptation with CarSim to provide a simulation tool that can be utilized in both tire and vehicle design processes. In addition to model implementation, a parameterization procedure was developed to estimate the parameters of the rigid ring tire and enveloping model based on experimental data for a given tire. Validation studies have also been performed to ensure the accuracy and validity of the tire model. Following this, the braking performance of ABS under different road surfaces were evaluated. Based on the simulation results, final conclusions were drawn with regards to the analysis and detailed recommendations for future work directed towards the improvement of the tool were provided. / Master of Science

The principle of braking in road vehicles involves the conversion of kinetic energy into heat. This high energy conversion therefore demands an appropriate rate of heat dissipation if a reasonable temperature and performance stability are to be maintained. While the design, construction, and location features severely limit the heat dissipation function of the friction brake, electromagnetic brakes work in a relatively cool condition and avoid problems that friction brakes face by using a totally different working principle and installation location. By using the electromagnetic brake as supplementary retardation equipment, the friction brakes can be used less frequently and therefore practically never reach high temperatures. The brake linings thus have a longer life span, and the potential "brake fade" problem can be avoided. It is apparent that the electromagnetic brake is an essential complement to the safe braking of heavy vehicles. In this thesis, a new mathematical model for electromagnetic brakes is proposed to describe their static characteristics (angular speed versus brake torque). The performance of the new mathematical model is better than the other three models available in the literature in a least-square sense. Compared with old models that treat reluctance as a constant, our model treats reluctance as a function of speed. In this way, the model represents more precisely the aggregate effect of all side effects such as degree of saturation of the iron in the magnet, demagnetizing effects, and air gap. The software program written in Matlab can be used to code different brake characteristics (both static and dynamic) and evaluate their performance in different road scenarios. A controller is designed that achieves wheel-slip control for vehicle motion. The objective of this brake control system is to keep the wheel slip at an ideal value so that the tire can still generate lateral and steering forces as well as shorter stopping distances. In order to control the wheel slip, vehicle system dynamic equations are given in terms of wheel slip. The system shows the nonlinearities and uncertainties. Hence, a nonlinear control strategy based on sliding mode, which is a standard approach to tackle the parametric and modeling uncertainties of a nonlinear system, is chosen for slip control. Due to its robustness properties, the sliding mode controller can solve two major difficulties involved in the design of a braking control algorithm: 1) the vehicle system is highly nonlinear with time-varying parameters and uncertainties; 2) the performance of the system depends strongly on the knowledge of the tire/road surface condition. A nominal vehicle system model is simulated in software and a sliding mode controller is designed to maintain the wheel slip at a given value. The brake control system has desired performance in the simulation. It can be proven from this study that the electromagnetic brake is effective supplementary retardation equipment. The application and control of electromagnetic brakes might be integrated with the design of vehicles and their friction braking systems so that an ideal match of the complementary benefits of both systems might be obtained to increase safety to a maximum while reducing vehicle operating costs to a minimum. / Master of Science