The compound 3-phenylindole (3PI) is a particularly active antimicrobial which interacts with phospholipids in fungal mycelia membranes, and which strongly inhibits the uptake of phosphate into fungal mycelia. The physical effects of 3PI on ion transport across bilayer lipid membranes composed of phosphatidylcholine/cholesterol have been investigated using three lipophilic ions and one ion/carrier complex. It was found that 3PI increased the electrical conductivity induced by the lipophilic cation (tetraphenylarsonium) and by the positively charged complex (nonactin-K('+)) by several orders of magnitude whereas 3PI decreased the conductivity induced by the two lipophilic anions (tetraphenylborate, dipicrylamine) by a factor of less than ten. These conductivity changes are explained as a combination of changes in the electrostatic and in the non-electrostatic properties of the bilayer. The electrostatic potential of the bilayer interior was shown to decrease in the presence of 3PI, a phenomenon which was also confirmed by measurements of the surface potential of phosphatidylcholine/cholesterol monolayers. The changes in non-electrostatic properties of the bilayer are qualitatively discussed in terms of increased bilayer fluidity or decreased bilayer thickness brought about by the presence of 3PI. The partition coefficient of the lipophilic anions, as determined by the voltage-step transient current technique, decreased slightly when 3PI was present in the aqueous phase. From the voltage dependence of the normalized steady state conductivity it was shown that 3PI did not kinetically limit tetraphenylarsonium transport but that it did kinetically limit nonactin-K('+) transport at concentrations greater than 25 (mu)M 3PI. The theory of carrier-mediated transport predicts the occurrence of transient currents in the kinetically limited regime but no transients were detected for nonactin-K('+) in the presence of 80 (mu)M 3PI. A method for analyzing the adsorption of neutral lipophilic molecules onto lipid monolayers has been presented, and by this method it was found that the partition coefficient of 3PI onto phosphatidylcholine/cholesterol monolayers was 1.3 x 10('-4) m and that the maximum adsorbed surface number density of 3PI was 1.1 x 10('-6) moles/m('2). From the experimental changes in monolayer surface potential as a function of adsorbed surface number density, a value for the normal component of the dipole moment of 3PI was obtained.

Permeable reactive barrier (PRB) technology is increasingly considered for in situ treatment of contaminated groundwater; however, current design formulas for PRBs are limited and do not properly account for all major physical and attenuation processes driving remediation. This study focused on developing a simple methodology to design PRBs that is easy to implement while improving accuracy and being more conservative than the available design methodologies. An empirical design equation and a simple analytical design equation were obtained to calculate the thickness of a PRB capable of degrading a contaminant from a source contaminant concentration to a maximum contaminant level at a Point of compliance . Both equations integrate the fundamental components that drive the natural attenuation process of the aquifer and the reactive capacity of the PRB.The empirical design equation was derived from a dataset of random hypothetical cases that used the solutions of the PRB conceptual model (Solution I). The analytical design equation was derived from particular solutions of the model (Solution II) which the study showed fit the complex solutions of the model well. Using the hypothetical cases, the analytical equation has shown that it gives an estimated thickness of the PRB just 15 % lower or higher than the real thickness of the PRB 95 percent of the time. To calculate the design thickness of a PRB, Natural attenuation capacity of the aquifer can be estimated from the observed contaminant concentration changes along aquifer flowpaths prior to the installation of a PRB. Bench-scale or pilot testing can provide good estimates of the required residence times ( Gavaskar et al. 2000) , which will provide the reactive capacity of the PRB needed for the calculation. The results of this study suggest also that the installation location downgradient from the source of contaminant is flexible. If a PRB is installed in two different locations, it will achieve the same remediation goals. This important finding gives engineers and scientists the choice to adjust the location of their PRBs so that the overall project can be the most feasible and cost effective. / Master of Science

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg, 2017 / Among of the components of the fuel cell, the polymer electrolyte membrane is critical to the performance and life time of the cell. Over the years the mechanical properties of the membrane, water management have tended to limit its wide spread commercialization as an alternative source of the renewable energy for portable power units. Fuel cell continues to attract extensive research interest as potential source of renewable energy. This work focuses on the production of ionexchange membrane (IEM) for hydrogen fuel cell, using cheap and locally available starting materials. The polystyrene-butadiene rubber (SBR) of different styrene and butadiene compositions, have been explored for functionality in fuel cell application. The production process was conducted in three stages: the first stage involved hydrogenation process followed by sulfonation process. The second stage entailed the production of carbon nano-spheres for the blending in the hydrogenated sulfonated polystyrene-butadiene rubber. The blending was also done between hybrid nanoparticles and hydrogenated sulfonated polystyrenebutadiene rubber. The third stage was the casting in thin film of blended solutions employing the evaporative method and the use of casting tape machine technique. The thin film was later on characterized and tested in a single fuel cell stack. Controlled hydrogenation of SBR employing catalytic method was achieved with maximum degree of hydrogenation in the range of:  90 – 92% for SBR with 23.5% styrene content and for SBR 25% styrene content  76 – 80% for SBR with 40% styrene content and  82 – 92% for SBR with 52% styrene content. The optimum conditions of this process were obtained using the Design of Experiments. SBR was also hydrogenated using a photocatalytic method and the percentage of hydrogenation for all SBR compositions used was found in the range between 60 and 74%. The hydrogenation results using the catalyst were higher compared to those obtained with the photocatalytic method. Therefore they were used to develop the kinetic model for prediction of hydrogenation process. Langmuir – Hinshelwood models were reviewed in this project as they explain these heterogeneous catalytic processes. Data from the kinetic tests were fitted to Langmuir – Hinshelwood models and reaction constants were found in the range between 0.445 h-1 and 0.610 h-1 for the reaction temperature between 20 and 30°C. The hydrogenated SBR of different compositions were effectively sulfonated with chlorosulphonic acid employed as first sulfonating agent of concentrations 0.15, 0.175 and 0.25M for SBR 23.5 and 25% styrene content, for SBR 40% styrene content and for SBR 52% styrene content, respectively. The degree of sulfonation was found in the range between 56 and 72% depending on the rubber composition. Trimethylsilyl chlorosulfonate used as the second sulfonating agent was like wise attached to the same polymer back bone and the degree of sulfonation was between 59 and 74% depending on the rubber’s styrene content. Non-conductive carbon nanospheres (CNS) of uniform size of about 46 nm were produced employing the non-catalytic chemical vapour deposition method at 1000°C. Acetylene and argon were respectively used as carbon source and carrier gas, in a reactor of 16 mm in diameter. Successful blending of 4 wt% nanoparticles and hydrogenated sulfonated styrene butadiene solution was accomplished by magnetic stirring technique combined with ultrasonication at 60% amplitude. The blended solution was casted to produce a thin film membrane of 156 μm thickness. Further the tensile strength test of the membranes has shown an increase in Young’s Modulus by 72-120% for all the rubbers. This test was done using TA.XTplus, Texture Analyser machine. The water uptake increment was in the range of 20-27% and thermal stability in the range of 2-20% depending on the rubber composition. Purchased electrodes from FuelCellsEtc (USA), were pasted on both sides of the membranes by the means of hot press at 125oC for about 5 minutes at a pressure of 40 kPa. The Membrane Electrode Assembly (MEAs) fabricated were tested in the fuel cell stack. The highest power density of approximately 85mW/cm2 was obtained for 52% styrene nanocomposite membrane with 4% hybrid nanoparticles at the current density of 212.41mA/cm2 and the efficiency was between 41 and 43%. MEA fabricated with Nafion112 membrane was tested and yielded the open cell voltage of 0.79V, power density of about 77.34mW/cm2 and efficiency of 45%. Results obtained disclose that the MEA with nanocomposites based SBR 52% styrene composition yielded higher power density and higher voltage than the one with Nafion 112 which is one of the fuel cell membranes available on the market. The results obtained revealed that the nanocomposite membranes with 4% hybrid nanoparticles (CNS + SiO2) had higher voltage than the one with 4% CNS. These optimum conditions obtained in this work may be adopted for a typical continuous production of the membrane for hydrogen fuel cell. / MT2018

Devido à taxa de urbanização crescente e às deficiências do sistema de drenagem urbana, tem sido cada dia mais evidente a recorrência e o aumento das inundações nas cidades brasileiras. Nas últimas duas décadas, as medidas estruturais alternativas ganharam espaço nos grandes centros urbanos devido à possibilidade de redução do efeito das cheias através de sistemas de detenção e/ou retenção, sem transferir o volume incremental de água para a jusante. Esta dissertação objetiva analisar a relação custo/eficiência de reservatórios de detenção e de pavimentos permeáveis. Para tal, foi necessária a verificação da possibilidade de implantação do pavimento permeável sem infiltração, seguida da modelagem hidrológica com pavimento permeável e com reservatórios de detenção na bacia hidrográfica do rio Pirajuçara. Para o desenvolvimento dessas análises, foram realizadas simulações matemáticas com o software Hec-Hms. O software ArcGis foi a ferramenta SIG utilizada para a preparação dos dados de entrada. A base de dados que caracteriza os reservatórios de detenção foi fornecida pelo DAEE. Para o pavimento permeável, foram consultadas as pesquisas geradas em função do protótipo de pavimento permeável, implantado no estacionamento do Centro Tecnológico de Hidráulica e Recursos Hídricos, dentro da Universidade de São Paulo. Com as simulações e análises desenvolvidas, foi possível quantificar a redução do escoamento superficial gerado e estimar o custo de reservatórios de detenção e pavimento permeável por unidade de redução do escoamento superficial. Este estudo evidencia que nas bacias de área menor, o uso do pavimento permeável apresenta uma boa relação custo/eficiência, sendo equivalente ao uso de reservatórios de detenção. Conclui-se que, quanto menor a área de implantação, mais competitivo fica o uso do pavimento permeável como medida estruturante. / The increasing urbanization rate and deficiency of urban drainage systems in Brazil has contributed to changes in the recurrence and impacts of urban floods. The actions to reduce the magnitude and damages caused by floods so far are mostly local and focused on classical solutions of urban drainage. The use of structural measures during the last two decades have increased in urban centers due to its effectiveness in reducing the effects of floods without transferring the incremental volume of water to downstream. The most common solutions are detention and/or retention systems. The objective of this dissertation is to analyze the relationship between cost and efficiency of detention reservoirs and permeable pavements. The feasibility of the implementing permeable pavements with retention underneath, that is, permeable pavements that do not infiltrate directly to the ground was analyzed in the Pirajuçara watershed area in São Paulo. A hydrological model was used to compare the response of the permeable pavement solution with the detention reservoirs already installed in the watershed. The hydrological simulation used the HEC-HMS software together with a GIS tool based on ArcGis software. The detention system database was provided by DAEE- Departamento de Águas e Energia Elétrica. The permeable pavement data on cost and efficiency was derived from the prototype installed the parking lot of the Centro Tecnológico de Hidráulica e Recursos Hídricos at the Universidade de São Paulo. This study was able to quantify the reduction of runoff generated, estimate the cost of permeable pavements per unit of reduction and compare it with the peak reduction of the reservoirs. This study showed that, on small watersheds, the use of permeable pavement presents a better cost/efficiency relationship, equivalent to the use of detention reservoirs. The conclusion is that the smaller the watershed, the more competitive is the solution of permeable pavement when compared to other structural measures.

This research offers permeable Spirit ecclesiology as a viable way forward for the churches in the context of the challenges in North India. Broadly, the challenges of the church in North India are twofold: one, to be an Indian Christian church amidst the plural religio-cultural context; second, to be in solidarity with the struggles of the marginalised. In other words, the church arguably ought to be relational with other communities and rooted in the North Indian context; on the other, it should critically and distinctly witness for Christ as a community of liberation in the context of the struggles of the marginalised. Thus, the church in North India arguably needs a relational-distinctive dialectics to address the challenges. This calls for a church with permeable borders to uphold the above in tension. I show that such dialectics can be upheld if ecclesiology in North India is construed from a pneumatological perspective with a Christological dimension. In dialogue with both Western and Indian theologians I show that a permeable Spirit ecclesiology is a viable way forward for the churches in North India.

Devido à taxa de urbanização crescente e às deficiências do sistema de drenagem urbana, tem sido cada dia mais evidente a recorrência e o aumento das inundações nas cidades brasileiras. Nas últimas duas décadas, as medidas estruturais alternativas ganharam espaço nos grandes centros urbanos devido à possibilidade de redução do efeito das cheias através de sistemas de detenção e/ou retenção, sem transferir o volume incremental de água para a jusante. Esta dissertação objetiva analisar a relação custo/eficiência de reservatórios de detenção e de pavimentos permeáveis. Para tal, foi necessária a verificação da possibilidade de implantação do pavimento permeável sem infiltração, seguida da modelagem hidrológica com pavimento permeável e com reservatórios de detenção na bacia hidrográfica do rio Pirajuçara. Para o desenvolvimento dessas análises, foram realizadas simulações matemáticas com o software Hec-Hms. O software ArcGis foi a ferramenta SIG utilizada para a preparação dos dados de entrada. A base de dados que caracteriza os reservatórios de detenção foi fornecida pelo DAEE. Para o pavimento permeável, foram consultadas as pesquisas geradas em função do protótipo de pavimento permeável, implantado no estacionamento do Centro Tecnológico de Hidráulica e Recursos Hídricos, dentro da Universidade de São Paulo. Com as simulações e análises desenvolvidas, foi possível quantificar a redução do escoamento superficial gerado e estimar o custo de reservatórios de detenção e pavimento permeável por unidade de redução do escoamento superficial. Este estudo evidencia que nas bacias de área menor, o uso do pavimento permeável apresenta uma boa relação custo/eficiência, sendo equivalente ao uso de reservatórios de detenção. Conclui-se que, quanto menor a área de implantação, mais competitivo fica o uso do pavimento permeável como medida estruturante. / The increasing urbanization rate and deficiency of urban drainage systems in Brazil has contributed to changes in the recurrence and impacts of urban floods. The actions to reduce the magnitude and damages caused by floods so far are mostly local and focused on classical solutions of urban drainage. The use of structural measures during the last two decades have increased in urban centers due to its effectiveness in reducing the effects of floods without transferring the incremental volume of water to downstream. The most common solutions are detention and/or retention systems. The objective of this dissertation is to analyze the relationship between cost and efficiency of detention reservoirs and permeable pavements. The feasibility of the implementing permeable pavements with retention underneath, that is, permeable pavements that do not infiltrate directly to the ground was analyzed in the Pirajuçara watershed area in São Paulo. A hydrological model was used to compare the response of the permeable pavement solution with the detention reservoirs already installed in the watershed. The hydrological simulation used the HEC-HMS software together with a GIS tool based on ArcGis software. The detention system database was provided by DAEE- Departamento de Águas e Energia Elétrica. The permeable pavement data on cost and efficiency was derived from the prototype installed the parking lot of the Centro Tecnológico de Hidráulica e Recursos Hídricos at the Universidade de São Paulo. This study was able to quantify the reduction of runoff generated, estimate the cost of permeable pavements per unit of reduction and compare it with the peak reduction of the reservoirs. This study showed that, on small watersheds, the use of permeable pavement presents a better cost/efficiency relationship, equivalent to the use of detention reservoirs. The conclusion is that the smaller the watershed, the more competitive is the solution of permeable pavement when compared to other structural measures.

The purpose of this study was to use controlled release technology combining with in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) to remediate TCE-contaminated groundwater. In this study, potassium permanganate (KMnO4) releasing material was designed for potassium permanganate release in groundwater. The components of potassium permanganate releasing material included poly (£`-caprolactone) (PCL), potassium permanganate, and starch with a weight ratio of 2:1:0.5. Approximately 63.8% (w/w) of potassium permanganate was released from the material after 76 days of operation. The released was able to oxidize contaminant in groundwater. Results from the solid oxidation demand (SOD) experiment show that the consumption rate increased with increased contaminant concentration. TCE removal efficiency increased with the increased TCE concentration. The second-order rate law can be used to simulate the TCE degradation trend. In the column experiment, results show that the released MnO4- could oxidize TCE and TCE degradation byproducts when 95.6 pore volume (PV) of contaminated groundwater was treated. More than 95% of TCE removal can be observed in the column study. Although the concentration of manganese dioxide (MnO2) began to rise after 8.8 PV of operation, TCE removal was not affected. Results also show that low level of hexavalent chromium was detected (< 0.05 mg/L). Results from the scanning electron microscope (SEM) and energy-dispersive spectroscope (EDX) analyses show that the amounts of manganese and potassium in the materials decreased after the releasing experiment. Results indicate that the concentration of TCE and SOD need to be analyzed before the releasing materials are applied in situ. In the practical application, the releasing materials will not become solid wastes because they are decomposed after use. If this slow-releasing technology can be combined with a permeable reactive barrier system, this technology will become a more economic and environmentally-friendly green remedial system.

Abstract A novel process of combining electrokinetic remediation and nano-sized iron wall was used for studying its effectiveness of treating nitrate-containing soil. Nitrates and nitrites are commonly found in surface water and groundwater. These substances, in general, could pose a threat to both organisms in the water bodies and human health. Traditionally, nitrogen oxides in various water bodies are treated by biological denitrification processes. However, it would take a longer time to yield a satisfactory result as compared with physicochemical processes. In recent years, permeable reactive barriers (PRBs) using zero-valent iron have been successfully used for degradation of various compounds including nitrates. Electrokinetic processing (EK) also is considered as an effective in-situ technology for removing both inorganic and organic substances from the treatment zone. In this work, the synthesized nano-scale iron particles were incorporated into a PRB, which was further combined with EK to form a novel process for the degradation of nitrates. Various operating parameters were studied in this work. The nano-sized iron particles were determined to be ranging from 50-80nm in size and having specific surface area of 37.83m2. The isoelctric point of these nanoparticles was found to be at pH 7.3. Experimental results have shown that the best location of the iron wall was 5cm from the anode reservoir. Also, the optimal treatment time would be six days in this study. The treatment efficiency was found to increase with increasing dose of nano-sized iron particles in the PRB. Operating with the polarity reverse would slightly increase the overall treatment efficiency as compared with the case of no polarity reverse (92.38% versus 88.34%). An electric gradient of 1.5V/cm was determined to be the optimal electric field strength in this study. In this work, it was also found that 2.5g nano-scale iron particles outperformed 20g micro-scale iron particles (75-150&#x00B5;m) in terms of nitrate degradation. In a study of using an extended treatment time up to 20 days, the black colored iron wall would fade away becoming a rusty plume toward the cathode as the treatment time elapsed. Furthermore, the Fe2+ concentration was elevated throughout the soil column after the 20-day treatment. Therefore, it is evident that nano-sized iron particles would migrate when they are subjected to EK. Based on the research findings obtained, the novel process employed in this study was found to be an effective one for in-situ treatment of nitrate-containing soil.

The increase in the contamination of ground-water (GW) with nitrates in both developing and developed countries mainly results from agricultural activities and improper sanitation systems, and is a recent phenomenon that has become a source of great health concern, particularly in regions where people rely on the ground-water as their primary water source. Due to the advantages of using Permeable Reactive Barriers (PRB) including its cost-effectiveness as well as its capability to remove or mitigate the spread of large spectrum of contaminants (including nitrates), a significant increase has been observed in the use of this subsurface treatment technology compared to other methods. However, identifying more economic and reliable reactive media to be used instead of the costly conventional PRB materials is now of key importance. Two local soils namely Berea Red Sand (BRS) and Umgeni Sand (US) were the main focus of this research. In addition to these soils, Zero Valent Iron (ZVI) was also used in this study. Through the use of batch experiments the feasibility of the nitrate reduction was investigated by five substrates including 100% ZVI, 100% BRS, 100% US, mix of 75% ZVI + 25% BRS, and mix of 50% ZVI + 50% BRS. Five concentrations of nitrate synthetic solution including 10 mg/l, 25 mg/l, 50 mg/l, 100 mg/l, and 500 mg/l were used to simulate nitrate-contaminated ground-water. All the batch experiments were performed under semi-aerobic and uncontrolled pH conditions, and only one solid/liquid ratio of 1:10 was used. The two mixes (mix of 75% ZVI + 25% BRS, and mix of 50% ZVI + 50% BRS) exhibited a nitrate removal efficiency of 100%, with all the different initial concentrations that were used with it; besides these two mixes, none of the other substrates showed this performance. 100% ZVI; however, managed complete nitrate reduction when the 10 mg/l and 25 mg/l concentrations were used. Finally, it was concluded that the benefits of using BRS in combination with other materials such as ZVI in the PRB field are promising. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2013.

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