The production of axisymmetric initial data for distorted black holes at a moment of time symmetry is considered within the (3+1) context of general relativity. The initial data is made to contain a distorted marginally trapped surface ensuring that, modulo cosmic censorship, the spacetime will contain a black hole. The resulting equations on the complicated domain are solved using the piecewise linear finite element method which adapts to the curved surface of the marginally trapped surface. The initial data is then analyzed to calculate the mass of the space time as well as an upper bound on the fraction of the total energy available for radiation. The families of initial data considered contain no more than few percent of the total energy available for radiation even in cases of extreme distortion. It is shown that the mass of certain initial data slices depend to first order on the area of the marginally trapped surface and the gaussian curvature of prominent features.

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The production of axisymmetric initial data for distorted black holes at a moment of time symmetry is considered within the (3+1) context of general relativity. The initial data is made to contain a distorted marginally trapped surface ensuring that, modulo cosmic censorship, the spacetime will contain a black hole. The resulting equations on the complicated domain are solved using the piecewise linear finite element method which adapts to the curved surface of the marginally trapped surface. The initial data is then analyzed to calculate the mass of the space time as well as an upper bound on the fraction of the total energy available for radiation. The families of initial data considered contain no more than few percent of the total energy available for radiation even in cases of extreme distortion. It is shown that the mass of certain initial data slices depend to first order on the area of the marginally trapped surface and the gaussian curvature of prominent features. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Along with the growth of Taiwan¡¦s capital markets, the public tend to serve stocks as the main investment tool. Underwriting markets are also monitored by investors. Generally, Taiwanese firms¡¦ stocks possess ¡§honeymoon periods¡¨ after they went public, in which the stocks kept gaining prices for consecutive days. Due to the phenomenon, companies tend to went public once the requirements are satisfied. On the other hand, investors are willing to purchase such stocks, thus let the underwriting market prosper. The aspect of initial public offerings (IPOs) is also gaining attention of researchers. This research aims at examining the relation between Taiwanese firms¡¦ IPOs¡¦ initial return and the Monday effect and Intra-month effect. This thesis also tried to discover that whether Taiwanese IPOs possess differences between size and industry groups. The results indicate that Taiwanese IPOs have lower return if issued in Mondays, which is the Monday effect. The reason may be that the closed market in weekends allowed investors to spend more time to search and to analyze information and to hinder themselves from overreaction. In addition, when issuing companies are determining underwriting prices, they tend to serve discount as a risk compensation for the uninformed investors, thus when investors have more time to analyze their investment decisions, the issuing companies need not to discount to induce investors.

Studying dynamical mechanisms of perturbation growth in tropical cyclones is important from a perspective of designing ensemble prediction system and adaptive observations for tropical cyclones. In this thesis, the role of perturbations in ensemble forecasting and adaptive observations for tropical cyclones is investigated, especially focusing on tropical cyclone tracks. For this purpose, ensemble initial perturbations from operational numerical weather prediction centers are first diagnosed, followed by a study in which the structure and location of singular vectors computed for tropical cyclone-like vortices in a nondivergent barotropic framework are investigated. The three most significant findings of this study are that 1) perturbations grow in the vicinity of tropical cyclones through both baroclinic and barotropic energy conversion as seen in mid-latitude dynamics, that 2) those energy conversions lead to the modification in tracks of tropical cyclones, and that 3) the structure and the location of growing perturbations are sensitive to initial temperature and wind profiles of the tropical cyclone vortex. The above results (1) and (2) determine a mechanism how the ensemble spread of tropical cyclone tracks evolves with time in ensemble prediction systems at operational numerical weather prediction centers. In addition, those results identify the reason why the ensemble spread differs from one ensemble prediction system to another. The result (3) gives an insight into understanding what sensitivity analysis guidance targeted for tropical cyclones represents and helps to optimize observation network for tropical cyclones.

When a firm decides to go public, two abnormalities often occur. The first is called underpricing and can be defined as a capital loss made by the company the first day of trade due to that the offer price is lower than the closing price after the first day of trade. The increase in stock value is equal to capital the issuing firm could have gained initially; this capital loss is referred to as the “money left on the table”. The second abnormality, underperformance, is a result from underpricing. It means that the stocks that were underpriced the first day also tend to underperform 3-5 years after the initial public offering (IPO) compared to competitors within the same industry. These two abnormalities together constitutes a problem for the firm because they loose money. However it also enables investors to make a quick profit. There are many studies covering this area, however mostly made by Americans, therefore the aim of this report is to investigate whether the two abnormalities exist on the Swedish market. In order to fulfill the purpose, companies that were listed 1998-2007 were investigated. Their stock performance is analyzed both on the day of IPO, where we found that 51% of the companies listed were underpriced, with an average of 23%. Further, the average “money left on the table” per company was 3.9 MSEK. The stock prices have also been analyzed on a one- as well as a five year period after the IPO in order to analyze the long-run performance and later compare it to the rest of the industry as well as industry index. We found that most of the companies that where underpriced also tend to follow underperformance. However, how long they underperform depends in which industry they operate. The IT industry, for example had a negative performance after 5 years whereas the Industrials industry has the turning-point from negative performance before 5 years.

<p>When a firm decides to go public, two abnormalities often occur. The first is called underpricing and can be defined as a capital loss made by the company the first day of trade due to that the offer price is lower than the closing price after the first day of trade. The increase in stock value is equal to capital the issuing firm could have gained initially; this capital loss is referred to as the “money left on the table”. The second abnormality, underperformance, is a result from underpricing. It means that the stocks that were underpriced the first day also tend to underperform 3-5 years after the initial public offering (IPO) compared to competitors within the same industry.</p><p>These two abnormalities together constitutes a problem for the firm because they loose money. However it also enables investors to make a quick profit. There are many studies covering this area, however mostly made by Americans, therefore the aim of this report is to investigate whether the two abnormalities exist on the Swedish market.</p><p>In order to fulfill the purpose, companies that were listed 1998-2007 were investigated. Their stock performance is analyzed both on the day of IPO, where we found that 51% of the companies listed were underpriced, with an average of 23%. Further, the average “money left on the table” per company was 3.9 MSEK. The stock prices have also been analyzed on a one- as well as a five year period after the IPO in order to analyze the long-run performance and later compare it to the rest of the industry as well as industry index. We found that most of the companies that where underpriced also tend to follow underperformance. However, how long they underperform depends in which industry they operate. The IT industry, for example had a negative performance after 5 years whereas the Industrials industry has the turning-point from negative performance before 5 years.</p>

This thesis discusses the effect of initial particle size and alloying of Pt nanocatalysts on the degradation of Proton Exchange Membrane Fuel Cells (PEMFC). Platinum nanocatalysts with initial particle sizes of 2.2nm, 3.2nm, 5.0nm, 6.7nm and 11.3nm were studied, before and after potential cycling. The two smallest initial particle sizes show significant degradation, while the remainder of the samples show negligible degradation after 10,000 cycles. Among the possible degradation mechanisms operating, the results show that dissolution and re-precipitation is insignificant among all the samples. On the other hand, modified electrochemical Ostwald ripening (MEOR) is the main cause for particle growth and degradation of the Pt nanocatalysts. Moreover, MEOR could also assist the coalescence of particles. Thus, controlling the Pt dissolution rate is the key factor to prevent degradation. In the case of Pt₃Co nanocatalysts, both MEOR as well as dissolution & reprecipitation play an irrelevant role in degradation. However, particle migration and coalescence seems to be more severe in Pt₃Co nanoparticles than for Pt nanoparticles. / text

This paper presents a seminal analysis of firms withdrawn from the IPO market (post security regulation filings) that return later for a subsequent IPO. This study contributes to the existing literature in four ways. First, by using IPO data from 1997 to 2012 in the Japanese market, the study extends the analysis on key determinants of a firm’s returning decision after an IPO withdrawal to the Japanese market. Secondly, it identifies VC ownership percentage and market run-up value 20 ~ 40 days prior to the withdrawn IPO as the key determinants of the probability a firm will return. Thirdly, using the duration model, the paper finds that an increase in VC ownership percentage and market run-up value 0 ~ 20 days prior to the withdrawn IPO allow the subsequent IPO to take place sooner. Finally, this paper attempts to find a correlation between macroeconomic indicators and the number of withdrawals at a given time. These findings can help find the factors that influence a firm’s decision in pursuing the public market option even after a failed attempt. However, censoring issues and the use of non-stationary variables remain as limitations to my findings.

This thesis studies the present methods used to predict the ultimate tripping strength of stiffened panels under compressive axial stress. The current methods involve the use of a bifurcation, or eigenvalue, approach to predicting failure stress. The effects of initial transverse eccentricity of the stiffener are ignored using such a method. Six panels were modeled and tested with ABAQUS, a finite element software package, and the results were compared to output from ULSAP, a closed-form ultimate strength analysis program. The ultimate strengths predicted by ABAQUS changed with the influence of initial deflection of the stiffener flange, while the results from ULSAP did not change. This thesis attempts to use beam-column analysis on the imperfect stiffener flange to predict the tripping strength. It was determined that the procedure presented in this thesis does not accurately model the true failure mode of stiffeners in tripping. The resulting ultimate strengths are extremely conservative and neglect the importance of the stiffener web's role in tripping. Future work is recommended to expand on these findings and to incorporate the influence of the stiffener web into a beam-column solution. / Master of Science