Esta pesquisa consistiu na verificação do comportamento do reator UASB de bancada (volume igual a 10,5 litros), quando submetido a variações senoidais de vazão afluente, comparando-se com a eficiência no seu funcionamento com vazão constante, através de análises de amostras de afluentes e efluentes. O reator UASB utilizado foi montado no Laboratório de Processos Biológicos da EESC-USP dentro de uma câmara com temperatura constante de 30 ± 3°C, e alimentado com esgoto sintético, com DQO de 500 mg/l, 750 mg/l e 1000 mg/l. O reator foi inoculado em abril de 1999, com 3,5 litros de lodo anaeróbio proveniente de um reator compartimentado, também situado na EESC-USP. Devido à dificuldade de atingir um valor esperado para a eficiência de remoção de Matéria orgânica, foi dada nova partida no reator, em julho de 1999, desta vez com lodo proveniente de outro UASB. Após a segunda partida, o reator operou com vazão constante e DQO afluente em torno de 500 mg/l até setembro de 1999, com média de remoção de DQO bruta de 75% no período, passando-se, então, à fase de variação senoidal de vazão de forma que o máximo e o mínimo fossem de ±30%, ±45% e ±60% da vazão média. Para este regime, obteve-se 80% de eficiência média de remoção de DQO bruta. Os valores de pH, alcalinidade e ácidos voláteis foram praticamente constantes durante a operação. Os perfis de remoção de DQO ao longo do dia mostraram uma pequena queda na eficiência do reator, aproximadamente 1,5 vezes o tempo de detenção hidráulica médio (8 horas), após os máximos de vazão para o regime de variação de vazão de ±30% e ±45% e 2,5 vezes o tempo de detenção hidráulica médio, para variação e ±60%. O mesmo experimento foi repetido para DQO afluente de 1000 mg/l e obteve-se, em média, eficiências de 65% de remoção de DQO. / This research consisted in the UASB reactor performance verification when it was submitted to sine-based variations of loading rate, in comparison to its normal operation. The UASB reactor used was set up at the Biological Process Laboratory of EESC-USP, inside a camera with temperature of 30°C ± 3°C. It was fed with synthetic sewage (COD = 500, 750 and 1000 mg/l). After start-up, the reactor was operated with constant loading rate (COD = 500 mg/l) until September 1999. The organic matter removal average in this period was 75%. Then, it was initiated the phase of sine-based variation loading rate (±30%, ±45% and ±60%). In this regime, it was obtained a medium gross COD removal efficiency of 80%. The pH values, alkalinity and volatile acids were practically constant during the operation. The COD removal profiles during the day showed a subtle fall in the reactor efficiency after 1.5 times the medium hydraulic detection time, for the loading rate variation of ±30% and ±45%. For ±60% variation, the answer time was approximately 2.5 times the medium hydraulic detection time. The efficiency of gross COD removal stay however over 78,53% until the experiment 9, witch showed that the reactor can stand the loading rate variations. The efficiency of filtered COD removal decreased on the second experiment, came back to the initial values and decreased again. The values of variation didn\'t surpass 6,6% for gross COD and 8,43% for filtered COD.

Esta pesquisa consistiu na verificação do comportamento do reator UASB de bancada (volume igual a 10,5 litros), quando submetido a variações senoidais de vazão afluente, comparando-se com a eficiência no seu funcionamento com vazão constante, através de análises de amostras de afluentes e efluentes. O reator UASB utilizado foi montado no Laboratório de Processos Biológicos da EESC-USP dentro de uma câmara com temperatura constante de 30 ± 3°C, e alimentado com esgoto sintético, com DQO de 500 mg/l, 750 mg/l e 1000 mg/l. O reator foi inoculado em abril de 1999, com 3,5 litros de lodo anaeróbio proveniente de um reator compartimentado, também situado na EESC-USP. Devido à dificuldade de atingir um valor esperado para a eficiência de remoção de Matéria orgânica, foi dada nova partida no reator, em julho de 1999, desta vez com lodo proveniente de outro UASB. Após a segunda partida, o reator operou com vazão constante e DQO afluente em torno de 500 mg/l até setembro de 1999, com média de remoção de DQO bruta de 75% no período, passando-se, então, à fase de variação senoidal de vazão de forma que o máximo e o mínimo fossem de ±30%, ±45% e ±60% da vazão média. Para este regime, obteve-se 80% de eficiência média de remoção de DQO bruta. Os valores de pH, alcalinidade e ácidos voláteis foram praticamente constantes durante a operação. Os perfis de remoção de DQO ao longo do dia mostraram uma pequena queda na eficiência do reator, aproximadamente 1,5 vezes o tempo de detenção hidráulica médio (8 horas), após os máximos de vazão para o regime de variação de vazão de ±30% e ±45% e 2,5 vezes o tempo de detenção hidráulica médio, para variação e ±60%. O mesmo experimento foi repetido para DQO afluente de 1000 mg/l e obteve-se, em média, eficiências de 65% de remoção de DQO. / This research consisted in the UASB reactor performance verification when it was submitted to sine-based variations of loading rate, in comparison to its normal operation. The UASB reactor used was set up at the Biological Process Laboratory of EESC-USP, inside a camera with temperature of 30°C ± 3°C. It was fed with synthetic sewage (COD = 500, 750 and 1000 mg/l). After start-up, the reactor was operated with constant loading rate (COD = 500 mg/l) until September 1999. The organic matter removal average in this period was 75%. Then, it was initiated the phase of sine-based variation loading rate (±30%, ±45% and ±60%). In this regime, it was obtained a medium gross COD removal efficiency of 80%. The pH values, alkalinity and volatile acids were practically constant during the operation. The COD removal profiles during the day showed a subtle fall in the reactor efficiency after 1.5 times the medium hydraulic detection time, for the loading rate variation of ±30% and ±45%. For ±60% variation, the answer time was approximately 2.5 times the medium hydraulic detection time. The efficiency of gross COD removal stay however over 78,53% until the experiment 9, witch showed that the reactor can stand the loading rate variations. The efficiency of filtered COD removal decreased on the second experiment, came back to the initial values and decreased again. The values of variation didn\'t surpass 6,6% for gross COD and 8,43% for filtered COD.

Background: The most common injuries in new or novice runners include medial tibial stress syndrome and patellofemoral pain syndrome; both overuse injuries. It is known that novice runners use a rearfoot strike pattern 98% of the time while running in traditional running footwear. Furthermore, footwear that is constructed with less cushioning (minimal shoes) and is said to promote forefoot running has increased in popularity. It is still unknown if novice runners convert their strike pattern in minimal shoes or continue to use a rearfoot strike pattern. Consequences of continuing to use a rearfoot strike pattern with less cushioning underfoot include higher vertical loading rates which are directly related to the types of injuries experienced. Aside from the strike pattern in a given shoe, movement stability is an important feature in healthy locomotion. There is a trade-off between being overly stable and being too unstable while running. It is known that the level of experience in running is related to the amount of stride length variability. It is still unknown if altering midsole stiffness has an effect on local dynamic stability while running. Purpose: The primary purpose of this thesis was to compare landing kinematics and kinetics between trained and novice runners in minimal and traditional shoes. The secondary purpose of this thesis was to examine the effect of running experience and midsole construction on local dynamic stability at the ankle, knee and hip. Methods: Twelve trained runners and twelve novice runners were recruited for participation. Four prototypical shoe conditions were tested with midsole geometry and material stiffness being manipulated. This yielded traditional/soft, traditional/hard, minimal/soft and minimal/hard shoe conditions. Participants ran down a 30m indoor runway which was instrumented with force platforms to measure vertical loading rates and motion capture cameras to capture landing kinematics. Participants also ran on a treadmill in each shoe condition to allow for local dynamic stability to be estimated at the ankle, knee and hip in the sagittal plane. Results: Novice runners landed with increased knee extension compared to trained runners. Increasing midsole thickness of the shoes caused an increase in dorsi-flexion of the ankle at heel strike. Manipulating material stiffness did not influence landing kinematics but did influence kinetics. Furthermore, decreasing material stiffness lowered vertical loading rates. Trained runners exhibited increased local dynamic stability (more stable) at the ankle, knee and hip compared to novice runners. Local dynamic stability was not affected by midsole stiffness. Conclusions: Novice runners did not alter their strike pattern in minimally constructed shoes. For this reason, cushioning properties of the shoe dictated vertical loading rates upon the body. Shoe conditions did not alter landing kinematics above the ankle, which is where the between group differences existed as novice runners landed with a more extended knee. Running experience appears to play a role in knee orientation at landing and is unaffected by shoe condition. Local dynamic stability was affected by running experience and does not appear to be related to the shoe condition being worn. Even when kinematics changed across shoe conditions, the stability of the movement did not.

The aqueous geochemistry and hydrology of the North Fork of the American Fork River, its tributaries, and the ground water in the vicinity of the Pacific Mine site were investigated in order to determine what impact ground water entering the North Fork has on toxic metal loads in the river. Toxic metal contamination in the North Fork is great enough that brown and cutthroat trout have absorbed lead, cadmium, and arsenic in their tissues at concentrations that are hazardous to human health if consumed. Ground water that flows through the mine site flows directly through the mine tailings before entering the North Fork, which produces an acidic ground water plume that has high concentrations of toxic metals. Together, the surface water discharge results and toxic metals concentrations from the surface and ground waters were used to determine toxic metals loading rates in the North Fork and its tributaries. The results suggest that the dissolved toxic metals (As, Cd, Cu, Fe, Mn, Pb, and Zn) enter the North Fork when the river is gaining water from the ground water. However, the total toxic metal load generally decreases through the reach of river adjacent to the mine site and is significantly greater than the dissolved load. Cadmium and Mn travel as dissolved species while Cu, Fe, Pb, and Zn travel as suspended solids in the North Fork and its tributaries. Arsenic seems to be associated with both the suspended solids and travel in the dissolved state. The geochemical modeling program PHREEQC and the diffuse double layer surface complexation model were used to investigate the chemistry that controls toxic metal mobility and attenuation in the surface and ground waters at the mine site. Based on PHREEQC results, the most important reaction in these waters is the precipitation of hydrous fe1Tic oxide. The toxic metals that sorb to the hydrous ferric oxide are Cu, Pb, most importantly Zn, and to a lesser degree As.

Atmospheric deposition is a marginally understood source of nutrient loadings to waterbodies. Atmospheric deposition occurs via wet (rain, snow) and dry (gaseous and particulate transport) pathways. Bulk atmospheric deposition is defined as the total deposition from both wet and dry pathways. Utah Lake is a shallow eutrophic freshwater lake located in central Utah, USA. Recent studies have shown atmospheric deposition to be a significant contributor to the nutrient budget of Utah Lake. This study presents the analysis using three different methods of six years' worth of wet atmospheric deposition samples from nine locations around the lake, though these samples do include some contribution from dry deposition. We present and compare nutrient loads and nutrient loading rates for total phosphorus, total in-organic nitrogen, and ortho-phosphorus. We conclude that wet atmospheric deposition contributed between 309 to 529 tons of total phosphorus, 1,166 to 2,078 tons of total nitrogen, and 106 to 201 tons of ortho-phosphorus to the lake during the study period. We extracted loading rates for the calendar year (in tons per year) and winter/summer month (in tons per month) from the data from each of the three methods of analysis. We show that wet atmospheric deposition is a significant pathway in which nutrients are transported to Utah Lake.

The bond between concrete and reinforcing steel is fundamental to the load bearing capacity of reinforced concrete structures. Several experimental studies indicate strength or rather resistance enhancements coming with increasingly dynamic loading. The phenomenon is known as strain or loading rate effect and its causes are still not fully clarified. The work presented herein provides a numerical view of the bond of reinforcement in concrete and investigates its loading rate dependent behaviour. Finite element analyses focusing on structural and inertia effects are carried out. Modelling is conducted at the rib scale, where bond is predominately controlled by mechanical interaction. In the first step, the model is developed and calibrated. Its quality, credibility, and limitations are assessed by a series of numerical case studies and the results are compared with available experimental data. Numerical parametric studies follow. The loading rate dependence of bond is featured, loading rate dependent characteristics are identified, and conclusions on causes of the phenomenon drawn. It is shown that structural effects are strongly involved and the same holds for hydrostatic pressure stress states and inertia effects. The thesis concludes in reviewing currently available methods for incorporating the results into large-scale simulations and highlighting further investigations and developments that are necessary in order to design dynamic loading-resistant structures in the future.

The suitability of water hyacinth in biogas production was evaluated as a means of waste management in the interests of sustainable energy production. Batch anaerobic digestion (AD) of water hyacinth was conducted to determine the optimal pre-treatment method for maximum methane production. Physical pre-treatment methods produced a highest cumulative methane of 2.3 L during batch AD. The selected pre-treatment method, hand-cutting, was further evaluated in a semi-continuous AD using both mono- and co-digestion. The emphasis was on identifying microbial communities involved and their response to organic loading rates (OLRs). The Illumina Miseq results proved that bacterial communities were more sensitive to disturbances caused by irregular OLRs as compared to archaeal communities. In addition, the variation in substrate nutrients as a result of mono- and co-digestion of water hyacinth, contributed to variations in the bacterial diversity. For example, Bacteroides and Petrimonas diversity varied between mono- and co-digestion. Overall, the study verified that water hyacinth is a suitable feedstock for biogas production and the simple pre-treatment methods are recommended. Furthermore, OLRs influenced the microbial community structure and associated biogas yield. / National Research Foundation (South Africa) / Environmental Science / M. Sc. (Environmental Science)