Observational properties of rigidly rotating dust configurations

We study the observational properties of a class of exact solutions of Einstein's field equations describing stationary, axially symmetric, rigidly rotating dust (i.e. non interacting particles). We ask the question whether such solutions can describe astrophysical rotating dark matter clouds near the center of galaxies and we probe the possibility that they may constitute an alternative to supermassive black holes at the center of galaxies. We show that light emission from accretion disks made of ordinary baryonic matter in this space-time has several differences with respect to the emission of light from similar accretion disks around black holes. The shape of the iron K$\alpha$ line in the reflection spectrum of accretion disks can potentially distinguish this class of solution from the Kerr metric, but this may not be possible with current X-ray missions.Comment: 8 pages, 5 figures, to appear in EPJ

The relationship between motivation and perceived autonomy of individual and team sports athletes with disabilities

학위논문(석사)--서울대학교 대학원 :사범대학 체육교육과,글로벌스포츠매니지먼트전공,2019. 8. 이용호.Psychological preparation is important for athletes development and success in sport alongside with physical training. Satisfaction of psychological needs such as motivation and perception of autonomy given by coach is very important in understanding of athletes behavior and performance. Over the last three-decades scholars focused on investigation of motivation influence on performance and autonomy – supportive coaching of able – bodied athletes, however, only few researches dedicated to paralympic sport. Many previous researches showed differences between able – bodied and disabled athletes in terms of motivational behavior reasons to participate in sport, win orientation, competitiveness and autonomy perception. In addition, in addition, such factors as adaptive equipment, classification, venue accessibility and other paralympic sport specific factors also could make influence on athletes motivation. Therefore, implications of previous researches about able – bodied athletes cannot be directly applied on athletes with disabilities. The perception of autonomy given by coach is different in team and individual sport types because of its nature. For example, in individual sport athlete rely only on himself or herself, focus on skills development and need to be concentrated during whole competition. In team sport, where all athletes pursuit team goal, as well as concentration and skills, atmosphere and support in team can be crucial. Sometimes, team sports do not require excellent skill development but require fulfillment of team goals. Based on Self – Determination Theory (SDT) this research will investigate and compare relationship between motivation and autonomy of individual and team disability sport. The quantitative survey will be conducted among athletes with disabilities; questionnaire will include demographic questions (age, gender, sport type, disability onset, etc.), to evaluate motivation will be used Sport Motivation Scale – II, to evaluate autonomy will be used The Autonomy – Supportive Coaching Questionnaire. Survey will be conducted among Korean athletes with disabilities, which compete in individual and team sports and train in Icheon training center of Korean Paralympic Committee and Gyeonggido Sport Association for the Disabled.Abstract i Table of Contents iv Chapter 1. Introduction 1 1.1. Current Context 1 1.2. Background 2 1.3. Problem statement 5 1.4. Purpose of the study 5 1.5. Research questions 5 1.6. Significance of the study 6 Chapter 2. Literature review 7 2.1. Brief history of Paralympic sport 7 2.2. Challenges in Paralympic Movement 9 2.2.1. Classification challenges 9 2.2.2. Doping usage 12 2.2.3. Media coverage 13 2.2.4. Venues accessibility and adaptive equipment 14 2.3. Team and individual sport 17 2.4. Self – Determination Theory 21 2.6. Hypothesis 32 Chapter 3. Methodology 33 3.1. Participants. 33 3.2. Instruments. 34 3.3. Statistical analysis 37 3.4 Results 38 3.4.1 Descriptive Statistics. 38 3.4.2. Correlations between sub – variables of SMS-II and ACSQ. 39 3.4.3. Linear Regression Analysis 41 Chapter 4 Discussion 44 4.1. Findings 44 4.2. Limitations. 50 4.3. Conclusion 51 Bibliography 53 Appendix A 59Maste

The Caspian Sea Resources: The Foundation for a Path Forward for the Economic, Political and Social Development of Azerbaijan and Turkmenistan

This case study explores the Caspian Sea energy politics, specifically the Trans-Caspian Gas Pipeline (TCGP) project and the Azeri-Turkmen conflict over the three offshore oil and gas fields. The conflict has been a deadlock of the project. It is almost unfeasible constructing the TCGP underneath of the sea without finding a viable solution to the Azeri-Turkmen conflict. Discovering the essence of the problem may help to understand what is going on over there. However, without exploring domestic and international barriers in front of the bilateral (on the disputed offshore fields) and multilateral (on the TCGP project) negotiations, none could find aviable solution to these entangled problems. Thus, areas of the domestic-international interaction of the problem are addressed through a comparative analysis of the two countries under theguidance of the `two-level games' theory. This study argues by making small compromises to each other Azerbaijan and Turkmenistan will see not only the long term economic benefits of the TCGP but also immediate political and social benefits. Consequently, this work suggests this is the right time to build the pipeline to develop oil and natural gas resources of the Caspian Sea for the economic, political and social development of Azerbaijan and Turkmenistan

Determination of wastewater characteristics from Chemical Engineering Programme Laboratories

University Technology PETRONAS, UTP, has several wastewater treatment plants treating wastewater generated within the university campus. A small wastewater treatment plant located behind Chemical Engineering Programme Buildings is the subject matter for this project. Recently, issue on whether the existing Effluent Treatment Plant for Chemical Engineering Programme Buildings is suitable with the characteristics ofthe wasteproduced has been raised. Several characteristics of the wastewater influent to the wastewater plant were analyzed and as a result all the tested parameters except for chromium (VI) content showed that the existing plant is suitable with the characteristics of the waste produced. Hexavalent chromium concentration was found to be in the range of 0.05 - 0.086 mg/L, which is more than the allowable limit of 0.05 mg/L

The Analyses of Hard- and Soft- Switching SiC Schottky- Buck Converter Performance

In this project two types ofbuck converters, hard switching and soft switching buck converters are compared in term of power lossand reverse recovery current of diode in DC applications. The test circuit used is dc to dc buck converter circuit. The main switch ofcircuit is the IGBT and the same type ofIGBT is used for both techniques. The diode used is fastswitching type Silicon Carbide Schottky (SiC) diode. First semester theory research has been verified with simulations, which were conducted in Cadence Pspice 14.2. The power loss waveforms of diode and IGBT transistor were obtained. Using those power waveforms the energy loss of both circuits were calculated. Second semester, hard and soft switching choppercircuitswere constructed on PCB (Printed Circuit Boards), so that simulation results can be compared with experimentation results. All the PCB layouts were prepared in ARES IV. Powerloss waveforms were obtained from digital oscilloscope. The simulation and experimentation values are found to be quite close to one another. It has found that hard switching chopper has more energy losses comparing soft switching chopper. The main losses occur during SiC diode turn-off (caused by reverse recovery current), IGBT transistor turn-on (caused by ICe current spike) and the highest main loss is IGBT turn-off (caused by tailing time, tailing current). Reducing the turn-off and turn-on switching losses of the IGBT would imply decreasing of the total loss of the system. Thatcould be done by implementing zero voltage switching across the IGBT transistor which would decrease IGBT turn-on and turn-off losses

The Analyses of Hard- and Soft- Switching SiC Schottky- Buck Converter Performance

In this project two types ofbuck converters, hard switching and soft switching buck converters are compared in term of power lossand reverse recovery current of diode in DC applications. The test circuit used is dc to dc buck converter circuit. The main switch ofcircuit is the IGBT and the same type ofIGBT is used for both techniques. The diode used is fastswitching type Silicon Carbide Schottky (SiC) diode. First semester theory research has been verified with simulations, which were conducted in Cadence Pspice 14.2. The power loss waveforms of diode and IGBT transistor were obtained. Using those power waveforms the energy loss of both circuits were calculated. Second semester, hard and soft switching choppercircuitswere constructed on PCB (Printed Circuit Boards), so that simulation results can be compared with experimentation results. All the PCB layouts were prepared in ARES IV. Powerloss waveforms were obtained from digital oscilloscope. The simulation and experimentation values are found to be quite close to one another. It has found that hard switching chopper has more energy losses comparing soft switching chopper. The main losses occur during SiC diode turn-off (caused by reverse recovery current), IGBT transistor turn-on (caused by ICe current spike) and the highest main loss is IGBT turn-off (caused by tailing time, tailing current). Reducing the turn-off and turn-on switching losses of the IGBT would imply decreasing of the total loss of the system. Thatcould be done by implementing zero voltage switching across the IGBT transistor which would decrease IGBT turn-on and turn-off losses

Determination of wastewater characteristics from Chemical Engineering Programme Laboratories

University Technology PETRONAS, UTP, has several wastewater treatment plants treating wastewater generated within the university campus. A small wastewater treatment plant located behind Chemical Engineering Programme Buildings is the subject matter for this project. Recently, issue on whether the existing Effluent Treatment Plant for Chemical Engineering Programme Buildings is suitable with the characteristics ofthe wasteproduced has been raised. Several characteristics of the wastewater influent to the wastewater plant were analyzed and as a result all the tested parameters except for chromium (VI) content showed that the existing plant is suitable with the characteristics of the waste produced. Hexavalent chromium concentration was found to be in the range of 0.05 - 0.086 mg/L, which is more than the allowable limit of 0.05 mg/L

Über die retrograde Obturation mit MTA-Zement und Super-EBA-Zement bei der Wurzelspitzenresektion- eine vergleichende Fallstudie in Vivo

Entzug des Doktorgrades mit Bescheid vom 4. Mai 2018 durch die FAU.Objectives Endodontically treated teeth often show failure. Usually it's due to bacterial leakage at the apical tip. A surgical shortening of the apical tip of the root via a root tip resection and simultaneous retrograde root canal sealing will lead to pathological changes in the apical area, often followed by a healing process and eventually the tooth can be saved in its function. In this research the therapeutic potency of Pro-Root-MTA and Super- EBA-Cement, both root canal filling materials are under investigation. Materials and methods In the following study, 120 single rooted root canal treated teeth with apical ostitis and radiographic proven periapical radiolucencies, were surgically treated. Out of the 120 teeth, 60 were filled retrogradly with Pro-Root-MTA and Super-EBA-Cement. Preand postoperative radiographs were taken of these teeth. The PAI index was utilized to show the degree of changes in periapical radiolucencies. After 3 months clinical and radiographical healing processes were diagnosed and interpreted. Results The results showed that both material MTA and EBA used to retrogradely obturate the root canals drastically led to a reduction of the inflammatory processes. The grade 1 observed with 34 teeth 62% with retrograded fillings with Pro-Root-MTA and 31 with Super-EBA-Cement. Conclusion The retrograde obturation of root canal treated teeth with Pro-Root-MTA and Super- Eba-Cement achieves a good coronal seal which had a positive result in the healing process. Both successfully seal of the root canal and thus stimulate the healing process of the periapical lesion. Due to the results in this study, we can recommend the use of Pro-Root-MTA and Super-EBA-Cement.Hintergrund und Ziele Bei endodontisch behandelten Zähnen treten oft Misserfolge auf. Die Ursache liegt in der Regel in einem bakterienundichten Abschluss am Neoapex. Eine operative Kürzung der Wurzelspitze durch eine Wurzelspitzenresektion mit gleichzeitigem retrogradem Wurzelkanalobturation führt häufig zur Ausheilung einer pathologischen Veränderung im apikalen Bereich und damit zur Erhaltung des Zahnes. In einer klinischen Fallstudie wurde die therapeutische Wirkung der retrograden Wurzelkanalfüllmaterialien MTAPro- Root und Super-EBA-Zement überprüft. Materialen und Methode In der vorliegenden Studie wurden 120 operative Angriffe an einwurzeligen wurzelkanalgefüllten Zähnen mit apikaler Ostitis und radiologisch nachgewiesenen periapikalen Aufhellungen durchgeführt. Von diesen 120 Zähnen wurden jeweils 60 mit MTA-Pro-Root und Super-EBA-Zement retrograd gefüllt. Präoperativ und postoperativ erfolgten Röntgenaufnahmen des zu behandelnden Zahnes. Der Grad der Aufhellung wurde an Hand des periapikalen Indexes (PAI) festgestellt. Nach drei Monaten wurden klinische und röntgenologische Heilungsprozesse befundet und beurteilt. Ergebnisse Die Ergebnisse zeigten, dass beide untersuchten Materialien bei der retrograden Wurzelkanalobturation, MTA- und Super-EBA-Zement, zu deutlichen Rückgängen der Entzündungsprozesse geführt haben. Den Grad I zeigten 34 Zähne (62%) bei retrograder Füllung mit MTA und 31 Zähne (56%) mit Super-EBA. Schlussfolgerung Die retrograde Obturation der Wurzelkanäle durch Anwendung der MTA-Zement und Super-EBA-Zement erzielt einen guten apikalen Verschluss, was einen positiven Einfluss auf den Heilungsprozess hat. Beide Materialien erfüllen den Zweck, den Wurzelkanal dicht zu verschließen und somit eine Ausheilung des periradikulären Prozesses zu stimulieren. Aufgrund der in dieser Studie gewonnenen Ergebnisse kann die Verwendung von MTA-Zement und Super-EBA-Zement empfohlen werden