Several previous studies have compared design storms with continuous simulation results for the purposes of estimating flood frequency distributions. These previous studies were limited in scope to primarily urban single lumped catchments. This thesis attempted to perform a more detailed comparison of design storm and continuous simulation flood frequency distributions by extending the analysis to different basin types, as well as examining the effect of more complex watershed systems and storage elements (detention ponds). It was found that design storms could reasonably reproduce continuous simulation flood frequency distributions if an appropriate distribution and antecedent conditions were selected. Design storms were found to compare increasingly well to continuous simulation results in more complex watershed systems and through storage elements. / Thesis / Master of Applied Science (MASc)

1 / xu zhou

An enormous and urgent energy demand is predicted due to the growing global population, increase in power intensive industries, higher living standards, electrification of remote areas, and globalisation (transportation). Moreover, the global consciousness about the harmful effects of traditional methods of power generation on the environment. That, in turn, has created a need to strategically plan and develop renewable and sustainable energy generation systems. This study presents a wind resource assessment of seven locations proximate to the largest industrial hub in the Middle East, Jubail Industrial City, Kingdom of Saudi Arabia, and a Geographic Information System, GIS based model considering a multi-criteria wind farm site suitability approach for the entire Kingdom of Saudi Arabia and elsewhere. The hourly mean wind speed data at 10, 50 and 90 m above the ground level (AGL) over a period of five years was used for a meteorological station at the Industrial Area (Central) of Jubail. At the remaining six sites, the meteorological data were recorded at 10 m AGL only. Five years of wind data were used for five sites and three years of data were available for the remaining one site. At the Industrial Area (East), the mean wind speeds were found to be 3.34, 4.79 and 5.35 m/s at 10, 50 and 90 m AGL, respectively. At 50 and 90 m AGL, the availability of wind speed above 3.5 m/s was more than 75%. The local wind shear exponent, calculated using measured wind speed values at three heights, was found to be 0.217. The mean wind power density values at measurement heights were 50.92, 116.03 and 168.46 W/m2, respectively. After the assessment and comparison of wind characteristics of all seven sites, the highest annual mean wind speed of 4.52 m/s was observed at Industrial Area (East) and the lowest of 2.52 m/s at the Pearl Beach with standard deviations of 2.52 and 1.1 m/s, respectively. In general, at all sites, the highest monthly mean wind speed was observed in February/June and the lowest in September/October. The period of higher wind availability coincides with a high power demand period in the region attributable to the air conditioning load. The wind rose plots show that the prevailing wind direction for all sites was from the north-west. Weibull parameters for all sites were estimated using maximum likelihood, least-squares regression method (LSRM), and WAsP algorithm. In general, at all sites, the Weibull parameter, c, was the highest in the months of February/June and the lowest in the month of October. The most probable and maximum energy carrying wind speed was determined by all three methods. The highest value of most probable wind speed was found to be in the range of 3.2 m/s to 3.6 m/s at Industrial Area (East) and the highest value of maximum energy carrying wind speed was found to be in the range 8.6 m/s to 9.0 m/s at Industrial Area 2 (South) by three estimation methods. The correlation coefficient (R2), root mean square error (RMSE), mean bias error (MBE), and mean bias absolute error (MAE) showed that all three methods represent wind data at all sites accurately. However, the maximum likelihood method is slightly better than LSRM, followed by WAsP algorithm. The wind power output at all seven sites, from five commercially available wind turbines of rated power ranging from 1.8 to 3.3 MW, showed that Industrial Area (East) is most promising for wind farm development. At all sites, based on percentage plant capacity factor, PCF, the 1.8 MW wind turbine was found to be the most efficient. At Industrial Area (East), this wind turbine was found to have a maximum PCF of 41.8%, producing 6,589 MWh/year energy output. The second best wind turbine was 3 MW at all locations except the Al-Bahar Desalination Plant and Pearl Beach. At both of these locations, 3.3 MW was the next best option. The energy output from the 3 MW wind turbine at Industrial Area (East) was found to be 11,136 MWh/year with a PCF of 41.3%. The maximum duration of rated power output from all selected wind turbines was observed to be between 8 to 16.6% at Industrial Area 2 (South). The minimum duration of rated power output, less than 0.3% for all wind turbines, was observed at Pearl Beach. The maximum duration of zero power output of between 35 to 60% was also observed at Pearl Beach. / Thesis (PhD)--University of Pretoria, 2017. / Mechanical and Aeronautical Engineering / PhD / Unrestricted

In the 21st century, the proliferation of steer-by-wire systems has become a central issue in the automobile industry. With such systems there is often an objective to minimise vibrations on the steering wheel to increase driver comfort. Nevertheless, steering wheel vibration is also recognised as an important medium that assists drivers in judging the vehicle's subsystems dynamics as well as to indicate important information such as the presence of danger. This has led to studies of the possible role of vibrational stimuli towards informing drivers of environment conditions such as road surface types. Numerous prior studies were done to identify how characteristics of steering wheel vibrational stimuli might influence driver road surface detection which suggested that there is no single, optimal, acceleration gain that could improve the detection of all road surface types. There is currently a lack of studies on the characteristics of transient vibrations of steering wheel as appear to be an important source of information to the driver road surface detection. Therefore, this study is design to identify the similarity characteristics of transient vibrations for answering the main research question: "What are the time-domain features of transient vibrations that can optimise driver road surface detection?" This study starts by critically reviewing the existing principles of transient vibrations detection to ensure that the identified transient vibrations from original steering wheel vibrations satisfy with the definition of transient vibrations. The study continues by performing the experimental activities to identify the optimal measurement signal for both identification process of transient vibrations and driver road surface detection without taking for granted the basic measurement of signal processing. The studies then identify the similarity of transient vibrations according to their time-domain features. The studies done by performing the high-dimensional reduction techniques associated with clustering methods. Result suggests that the time-domain features of transient vibrations that can optimise driver road surface detection were found to consist of duration (Δt), amplitude (m/s2), energy (r.m.s) and Kurtosis.

No description available.

No abstract provided. / Thesis / Doctor of Philosophy (PhD) / Scope and contents: The atomic vibrations in rubidium have been studied by the method of slow neutron spectrometry. The results have been analysed to yield atomic force constants which are used to compute the phonon frequency distribution. An interesting effect in the [00ζ]L branch has been examined, and an explanation of the observations is offered. Anharmonic calculations of frequency shifts and widths are presented, as well as a calculation of the anharmonic heat capacity. The third and fourth derivatives of the real space interatomic potential, which are required for these computations, are estimated in various ways. A determination of the lattice spacing of rubidium by neutron diffraction is described.

No description available.

No description available.

In this work, we constructed a new model for the collisional evolution of the Main Asteroid Belt. Our goals are to test the scaling law from the work of Benz & Asphaug (1999) and ascertain if it can be used for the whole belt. We want to find initial size-frequency distributions (SFDs) for the considered six parts of the belt, and to verify if the number of asteroid families created during the simulation matches the number of observed families as well. We used new observational data from the WISE satellite (Masiero et al., 2011) to construct the observed SFDs. We simulated mutual collisions of asteroids with a modified Boulder code (Morbidelli et al., 2009), in which the results of hydrodynamic (SPH) simulations from the work of Durda et al. (2007) are included. Because material characteris- tics can affect breakups, we created two models - for monolithic asteroids and for rubble-piles (Benavidez et al., 2012). The results for monolithic and rubble- -pile asteroids are comparable and in both cases the number of created families is, within uncertainties, consistent with the observations. A disagreement of the SFDs for a limited size range D 1 to 5 km a is a good motivation to conduct new SPH simulations with relatively small targets. 1

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-08-31T13:55:01Z No. of bitstreams: 1 2011 - Luciane Marins Bed?.pdf: 3568218 bytes, checksum: dd8b031aa116daa6b17232d9004b198b (MD5) / Made available in DSpace on 2016-08-31T13:55:01Z (GMT). No. of bitstreams: 1 2011 - Luciane Marins Bed?.pdf: 3568218 bytes, checksum: dd8b031aa116daa6b17232d9004b198b (MD5) Previous issue date: 2011-06-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This study was conducted in the Jabaquara mangrove, Paraty, Rio de Janeiro, with the aim of investigate the spatial distribution, population biology of brachyuran species and somatic growth of Uca rapax (Smith, 1870) (Crustacea, Decapoda, Ocypodidae) in the Jabaquara`s mangrove/Paraty - RJ. Sampling was performed in two grids from July 2007 to June 2008, using the capture effort per unit. Two collectors captured the crab monthly, during 15 minutes in low tide. Sediment samples from all the selected plots were collected to determinate particle size and organic matter. Air temperature and salinity also were measured. Eight species of brachyuran were captured, U. rapax, U. thayeri, U. vocator, U. uruguayensis, U. cumulanta, Neohelice granulata, Ucides cordatus and Eurytium limosum. U. rapax was the most abundant species in number of individuals and ovigerous females. The results indicated that distribution of the species was influenced by abiotic factors. The most species were more abundant in the inner portions of the mangroove and near of the sea. The ovigerous females of U. rapax were more abundant in the inner portions of the mangroove and near from the sea and N. granulata more distant from the sea. U. rapax showed a positive correlation with organic matter. U. thayeri, U. uruguayensis and E. limosum negatively correlated to distance from the sea. U. vocator showed positive correlation for sand and organic matter and negatively correlated to distance from the sea. U. cumulanta was positively correlated to sand. The ovigerous females of U. rapax showed a positive correlation to air temperature and organic matter. N. granulata and U. cordatus were the species more versatile in habitat colonization. The size of the crabs in the Jabaquara?s Mangrove were the smallest size than those found in other Brazilian mangroves. However, the males attained a larger size than females. The size frequency distribution was unimodal for the most species. In general, the males were predominant in all size classes, and more evident in larger classes. The sex ratio differ significant from 1:1 proportion (male: female), which most of the time dislocated for males. The most species showed a seasonal reproductive period, with more abundance of ovigerous females during the spring and summer. The growth curves in width (mm) for males and females were described by the equations: LC= 24,28 [ 1- e -0,0038(t-2,8) ] and LC= 22,0 [ 1- e -0,0031(t-2,3)], respectively. The males reach larger sizes and a higher growth rate than females. The longevity was estimated at three years for males and four years for females / Este trabalho foi realizado no manguezal de Jabaquara, em Paraty, Rio de Janeiro com o objetivo de analisar a distribui??o espacial, a biologia populacional das esp?cies de braqui?ros e o crescimento som?tico de Uca rapax (Smith, 1870) no manguezal de Jabaquara/ Paraty ? RJ. As coletas foram realizadas em dois grides de julho 2007 a junho2008, utilizando-se a t?cnica de esfor?o por unidade de captura. Dois coletores capturaram os caranguejos mensalmente, durante 15 minutos em per?odo de mar? baixa. Amostras de sedimento foram coletadas nas parcelas selecionadas, para determinar o tamanho das part?culas e mat?ria org?nica e a temperatura do ar e a salinidade tamb?m foram tomados. Foram capturadas oito esp?cies de braqui?ros: U. rapax, U. thayeri, U. vocator, U. uruguayensis, U. cumulanta, Neohelice granulata, Ucides cordatus e Eurytium limosum. U. rapax foi ? esp?cie mais abundante em n?mero de indiv?duos e de f?meas ov?geras. Os resultados revelaram que a distribui??o das esp?cies foi influenciada pelos fatores abi?ticos. A maioria das esp?cies foi mais abundante nas parcelas mais internas do manguezal e pr?ximas ao mar. As f?meas ov?geras de U. rapax e N. granulata foram mais abundantes nas parcelas mais internas do manguezal e mais pr?ximas e mais distantes do mar, respectivamente. U. rapax apresentou correla??o positiva para mat?ria org?nica. U. thayeri, U. uruguayensis e E. limosum apresentaram correla??o negativa para dist?ncia do mar. U. vocator apresentou correla??o positiva para areia e mat?ria org?nica e correla??o negativa para dist?ncia do mar. U. cumulanta apresentou correla??o positiva para areia. As f?meas ov?geras de U. rapax apresentaram uma correla??o positiva para temperatura do ar e mat?ria org?nica. N. granulata e U. cordatus foram as esp?cies mais vers?teis em formas de colonizar ambientes. Com rela??o ao tamanho dos indiv?duos, observou-se que os braqui?ros do Manguezal de Jabaquara, de maneira geral, apresentam tamanhos maiores que os encontrados em outros manguezais do Brasil. Contudo, os machos atingiram tamanhos maiores que as f?meas. A distribui??o de freq??ncia em classes de tamanho foi unimodal para a maioria das esp?cies. De maneira geral, os machos foram predominantes em todas as classes de tamanho, sendo mais evidente nas maiores classes. A raz?o sexual diferiu significativamente da propor??o 1:1, estando na maioria das vezes deslocada para os machos. A maioria das esp?cies apresentou um per?odo reprodutivo sazonal, ocorrendo maior abund?ncia de f?meas ov?geras na primavera e no ver?o. O modelo de von Bertalanffy foi utilizado para a descri??o do crescimento. As curvas de crescimento em largura (mm) para machos e f?meas de U. rapax, foram descritas pelas equa??es: LC= 24,28 [ 1- e -0,0038(t-2,8) ] e LC= 22,0 [ 1- e -0,0031(t-2,3)], respectivamente. Os machos apresentaram uma taxa de crescimento maior do que as f?meas. A longevidade foi estimada em 3 anos para os machos e 4 anos para as f?meas.