Diploma thesis deals with calculations of a steam turbine with two uncontrolled extraction points according to the assignment, aerodynamics of the last two stages and operating range with respect to ventilation, range of performance and straining of the last blading under the large condensation pressure deviations. For the first three stages the calculation of prismatic action blades is executed. The fourth and the fifth stages are designed with inconstant reaction over the blades length and their calculation is executed with constant circulation method. For these stages, aerofoil design with respect to their aerodynamic qualities is carried out using Bézier curves. During the whole time verification process of aerofoils qualities, their energy losses and isoentropic Mach number distribution is executed in MISES program in cooperation with Doosan Škoda Power.

This Master thesis deals with modification of lead battery charger connection. In particular, changes are made to the control board. The theoretical part describes the principle of charging lead batteries and the description of the basic types of switching power supplies. Furthermore, the dimensioning of important components in the circuit together with the optimization of the switching frequency and the parameters of the high-frequency transformer are also presented. At the end of the thesis is the procedure of assembling the whole charger.

The theme of this thesis is design of single body condensing steam turbine of 50 MW to saturated steam for new nuclear power plant generation. In the thesis is made design and calculation of balancing scheme. On the basis of the calculation is made blades part of turbine. Furthermore, the thesis solves basic strength and structural calculations. The result is drawing of longitudinal cut of the turbine.

Diploma thesis is composed of theoretical and practical part. In theoretical part there are findings related to structure changes of concrete exposed to high temperatures. Models used to simulate high temperature exposure of concrete are described in this thesis. Evaluation of internal structure damage is appropriate by using non-destructive methods, which determine dynamic modulus of elasticity in compression and tension. These methods includes ultrasonic impulse method and resonation method and therefore research was made of articles contains these methods. In experimental part of diploma thesis the test specimens was made from repair materials from UTHD and commercially produced repair materials. The test specimens were subjected to thermal load: 200, 400, 600, 800 °C. Damage of internal structure was examined by ultrasonic impulse method and resonation method.

Seventeen strength and power athletes (n = 11 males, 6 females; height: 177.5 ± 7.0 cm, 165.8 ± 11.4 cm; body mass: 90.0 ± 14.1 kg, 66.4 ± 13.9 kg; age: 30.6 ± 10.4 years, 30.8 ± 8.7 years), who regularly performed weightlifting movements during their resistance training programs, were recruited to examine the effect of altering body posture and barbell position on the between-session reliability of force-time characteristics generated in the isometric mid-thigh pull (IMTP). After participants were familiarised with the testing protocol, they undertook two testing sessions which were separated by seven days. In each session, the participants performed three maximal IMTP trials in each of the four testing positions examined, with the order of testing randomized. In each position, no significant differences were found between sessions for all force-time characteristics (p = >0.05). Peak force (PF), time-specific force (F50, F90, F150, F200, F250) and IMP time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) were reliable across each of the four testing positions (ICC ≥ 0.7, CV ≤ 15%). Time to peak force, peak RFD, RFD time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) and peak IMP were unreliable regardless of the testing position used (ICC =15%). Overall, the use of body postures and barbell positions during the IMTP that do not correspond to the second pull of the clean have no adverse effect on the reliability of the force-time characteristics generated.

Power line communication has been around in past decades and gained renewed attention thanks to the demand of high-speed Internet access. With the significant advantages of existing infrastructure and accessibility to even remote areas, power grid has become one of the promising competitors for multi-media transmission in household. However, the power line was not oriented for data transmission providing a rather hash environment. To overcome the difficulties, advanced modulation and channel coding schemes should be employed. In the thesis low density parity check code (LDPC) is employed to reduce the loss caused by various kinds of effects in the channel especially the noise since its performance approaches to Shannon capacity limit. Moreover, OFDM multi-carrier transmission technique is involved which could decrease the inter-symbol interference and frequency selective fading. Nevertheless, LDPC decoding process was designed specifically for the common Gaussian white noise condition, combined with OFDM modulation the system still could not provide satisfying and practicable performance so improvements are needed for the system. The main works of the thesis are as follows. Set up an environment of power line transmission investigating and simulating the channel characteristics; employ multi-path channel model and Class‐A noise model for further developing the improvement algorithms to deal with the selective fading and impulse noise. Two algorithms proposed here are from different perspectives: the first one is modifying initial posterior information for LDPC decoding and the second one aims at suppressing the impulse noise after demodulation. Finally, a few simulations are performed to reveal the effectiveness of proposed methods. As a result, the improved scheme shows a great superiority improving the performance by no less than 5dB compared to traditional system.

A turbine was investigated by various methods of calculating its efficiency. The project was based on an existing impulse turbine, a one-stage turbine set in an organic Rankine cycle with the working fluid being R245fa. Various methods of loss calculation were explored in the search for a method sufficiently accurate to make valid assumptions regarding the turbine performance, while simple enough to be time efficient for use in industrial research and development.  The calculations were primarily made in an isentropic manner, only taking into account losses due to the residual velocity present in the exit flow. Later, an incidence loss was incorporated in the isentropic calculations, resulting in additional losses at off-design conditions. Leaving the isentropic calculations, the work by Tournier, “Axial flow, multi-stage turbine and compressor models” was used. The work presents a method of calculating turbine losses separated into four components: profile, trailing edge, tip clearance and secondary losses. The losses applicable to the case were implemented into the model. Since the flow conditions of the present turbine are extreme, the results were not expected to coincide with the results of Tournier. In order to remedy this problem, the results were compared to results obtained through computational fluid dynamics (CFD) of the turbine. The equations purposed by Tournier were correlated in order to better match the present case. Despite that the equations by Tournier were correlated in order to adjust to the current conditions, the results of the losses calculated through the equations did not obtain results comparable to the ones of the available CFD simulations. More research within the subject is necessary, preferably using other software tools.

The purpose of this study is to examine and clarify what impulse purchases look like online. The method chosen was of a quantitative nature in the form of a digital survey and was used to try to answer the research question "What are the influencing factors when impulse buying online, and what are the influencing factors when impulse buying clothes online?". The digital surveys were shared on Facebook and Instagram and the data collected consisted of 177 responses.  Hawkins Stern's Impulse Buying Theory, Impulse Buying Tendencies (IBT) and Theory of Planned Behavior (TPB) were the theories used in this study and they were chosen based on its relevance and contribution to understanding impulse buying and possible influencing factors when impulse buying. Additional support for the study’s results, analysis and conclusions consisted of scientifically reviewed articles about the research area being studied. The results of this study show no possible influencing factors when impulse buying online or when impulse buying clothes online. / Undersökningens syfte är att studera hur impulsköp ser ut online. Metoden som valdes var av kvantitativ karaktär i form av en digital enkätundersökning och användes för att försöka besvara forskningsfrågan “Vilka är påverkansfaktorerna vid impulsköp online, och vilka är påverkansfaktorerna vid impulsköp av kläder online?”. Enkäterna skickades ut via Facebook och Instagram och insamlad data bestod av 177 respondentsvar.   Hawkins Sterns Impulse Buying Theory, Impulse Buying Tendencies (IBT) och Theory of Planned Behavior (TPB) var de teorier som användes i undersökningen och valet av dessa baserades på dess relevans och bidrag till förståelse vad gäller impulsköp och möjliga  påverkansfaktorer vid impulsköp. Ytterligare stöd till undersökningens resultat, analys och slutsatser bestod av vetenskapligt granskade artiklar som behandlar forskningsområdet som studerats. Undersökningens resultat visar inga specifika möjliga påverkansfaktorer vid impulsköp online eller vid impulsköp av kläder online.

<p>Development of complex aerospace systems often takes decades of research and testing. High  performing propellants are important to the success of rocket propulsion systems. Development  and testing of new propellants can be expensive and dangerous. Full scale tests are often required  to understand the performance of new propellants. Many industries have started using data science  tools to learn from previous work and conduct smarter tests. Material scientists have started using  these tools to speed up the development of new materials. These data science tools can be used to  speed up the development and design better propellants. I approach the development of new solid  propellants through two steps: Prediction of delivered performance from available literature tests,  prediction of ideal performance using physics-based models. Random Forest models are used to  correlate the ideal performance to delivered performance of a propellant based on the composition  and motor properties. I use Parsimonious Neural Networks (PNNs) to learn interpretable models  for the ideal performance of propellants. I find that the available open literature data is too biased  for the models to learn from and discover families of interpretable models to predict the ideal  performance of propellants. </p>

Thesis (M. Com. (Economics)) -- University of Limpopo, 2019 / Financial markets and quite a diverse number of financial instruments have been growing in a controlled manner in recent decades in terms of value and volume. Brazil, Russia, India, China and South Africa (BRICS) are distinguished as having the fast growing markets in the universe compared to other markets of emerging economies, according to their promising economic prospective and demographic power. This study investigated the effects of government stock on investment activity in BRICS countries. This study used panel autoregressive distributed lag model (PARDL), Engel-Granger causality test, impulse response functions (IRF) and variance decomposition tests. Such techniques were applied to the annual data for the periods 2001 to 2016 in order to determine the effects of government stock on investment activity. The variables (government stock on bonds, government stock on mutual banks, government stock on corporations and government stock on liquid assets), including gross fixed capital formation which is a measure of investment activity, were subjected to panel unit root tests and that confirmed different orders of cointegration. The existence of a long run relationship between investment activity and other macroeconomic variables used in this study was determined by means of the panel cointegration tests, where one lag was used. The PARDL showed that in the long run investment activity was positively influenced by government stock on mutual banks and government stock on liquid assets, and negatively related to government stock on bonds and government stock on corporations. The Engel-Granger causality test revealed existence of unidirectional movement between investment activity and government stock on corporations as well as from government stock on bonds to liquid assets. The impulse response function test showed the impulse percentage of fluctuation that the variables did contribute to each other, from various periods both in the short and long run. While the variance decomposition of investment indicated that Investment was shocked by its own innovations throughout all the periods. A critical evaluation is needed to avoid investment shocks, instability of investment activity, instability of financial markets and the economy as a whole.