Ion pumps establish homeostasis across the membranes of living cells. Hearing is a mechanotransduction event that takes place in a closed compartment containing a fluid high in K+ concentrations. In Drosophila melanogaster, this closed compartment is formed by a scolopale cell that wraps around the dendrite of sensory neurons. The receptor lymph is maintained by the scolopale cell. The lumenal membrane of the scolopale cell is the wall of the compartment containing the receptor lymph, the scolopale space. The ablumenal membrane of the scolopale cell creates the border of the scolopidium. The Na/K pump is located on the ablumenal membrane of the scolopale cell, bringing K+ into the scolopale cell cytoplasm and extruding K electrogenically (Roy et al, 2013). We explored other primary and secondary ion pumps that are involved in creating a K+-rich lumen in the Malpighian tubule (Day et al, 2008; Rodan et al, 2012). We used RNAi technology to knockdown one gene at a time and electrophysiology to measure a sound evoked potential (SEP) that reflects the fly’s ability to hear. We found that knocking down V-ATPase, a proton pump, subunits involved in proton extrusion significantly reduces the SEP of knockdown flies. The involvement of cation chloride cotransporters (CCCs) and cation proton antiporter (CPAs), both secondary ion pumps that use the gradients created by the Na/K pump and V-ATPase respectively to pump other ions up their gradient, is less clear. We found that knocking down Nhe3, a CPA, significantly reduced the SEP when knocked down in the scolopale cell, suggesting it as a partner to the V-ATPase. Knocking down CG31547, a CCC, statistically increased the SEP, possibly a type1 statistical error.

This dissertation study describes the development of novel heteroepitaxial growth of 3C-SiC layers by chemical vapor deposition (CVD). It was hypothesized that chloride addition to the "traditional" propane-silane-hydrogen precursors system will enhance the deposition growth rate and improve the material quality via reduced defect density. Thermodynamic equilibrium calculations were performed to obtain a criterion for which chloride specie to select for experimentation. This included the chlorocarbons, chlorosilanes, and hydrogen chloride (HCl) chloride containing groups. This study revealed no difference in the most dominant species present in the equilibrium composition mixture between the groups considered. Therefore, HCl was the chloride specie selected to test the hypothesis. CVD computerized fluid dynamic simulations were developed to predict the velocity, temperature and concentration profiles along the reactor. These simulations were performed using COMSOL Multiphysics and results are presented. The development of a high-temperature (1300 °C -1390°C) 3C-SiC growth process resulted in deposition rates up to ~38 µm/h. This is the highest value reported in the literature to date for 3C-SiC heteroepitaxy. XRD FWHM values obtained varied from 220 to 1160 arcsec depending of the process growth rate or film thickness. These values are superior or comparable to those reported in the literature. It was concluded from this study that at high deposition temperatures HCl addition to the precursor chemistry had the most significant impact on the epitaxial layer growth rate. Low-temperature (1000-1250°C) 3C-SiC growth experiments evidenced that the highest deposition rate that could be attained was ~2.5 µm/h. The best quality layer achieved in this study had a FWHM of 278 arcsec; which is comparable to values reported in the literature and to films grown at higher deposition temperatures in this study. It was concluded from this work that at lower deposition temperatures the HCl addition was more beneficial for the film quality by enhancing the surface. Surface roughness values for films grown with HCl additive were 10 times lower than for films grown without HCl. Characterization of the epitaxial layers was carried out via Nomarski optical microscopy, FTIR, SEM, AFM, XRD and XPS.

The objectives of this study were to investigate the long-term effects of feeding increasing supplemental levels (20, 120, or 220 mg/kg) of dietary copper (Cu) as tribasic copper chloride (TBCC) or copper sulfate (CuSO4) on performance, antioxidant status, nutrient digestibility, and trace mineral deposition of sows and piglets; as well as to assess nursery dietary Cu levels on growth performance and response to immunological challenge in nursery pigs from sows fed either high or low Cu diets. In the long-term sow experiment, sows fed TBCC diets had greater adjusted weaning weight for litter and piglet (P < 0.10), as well as adjusted litter and piglet weight gain (P < 0.10) when compared to sows that received CuSO4 diets. Increasing dietary Cu level linearly increased live born piglet weight (P = 0.06). Sows fed TBCC diets had lower apparent total tract digestibility (ATTD) of ether extract (P = 0.01) during late gestation, but greater ATTD of dry matter, nitrogen, and phosphorous during lactation (P < 0.05). Increasing Cu levels linearly increased dry matter digestibility in lactating sows (P = 0.02). Milk from sows fed TBCC diets had a greater concentration of protein (P = 0.02) than that from sows fed CuSO4 diets. Increasing Cu levels increased levels of milk fat and Cu (linear, P < 0.05); but linearly decreased lactose and Zn levels (P < 0.05). Lactating sows fed TBCC diets had a greater activity of Cu/Zn superoxide dismutase (SOD) and ceruloplasmin in serum than those fed CuSO4 diets (P < 0.05). Increasing dietary Cu levels increased total and Cu/Zn SOD activity for lactating sows (linear, P < 0.05). Sows fed TBCC diets had lower concentrations of Cu (P = 0.04), but higher concentrations of iron and manganese (P < 0.05) in the liver, when compared to those fed with CuSO4 diets. In addition, liver Cu concentrations increased with increasing dietary Cu levels (linear and quadratic, P < 0.05). Increasing dietary Cu levels resulted in the elevation of concentrations and contents of Cu in the liver of weanling piglets (linear, P < 0.0001). In the nursery pig experiment, pigs from sows fed 120 mg/kg Cu diets had greater ADG from d 0 to 14 (P < 0.05), and tended to have greater ADG in the overall period (P < 0.08), when compared to pigs from sows fed 20 mg/kg Cu diets. During the lipopolysaccharide challenge period, the challenged pigs from sows fed 120 mg/kg Cu had a greater overall rectal temperature than those from sows fed 20 mg/kg Cu (P = 0.01). Also, the challenged pigs fed with 220 mg/kg Cu diets had greater serum tumor necrosis factor-alpha concentration over time as compared to those fed 20 mg/kg Cu diets (P = 0.03). In summary, the TBCC may be a superior Cu source compared to CuSO4 regarding reproductive performance, and higher dietary Cu levels result in greater birth weight of piglets; furthermore, high Cu levels in sow and nursery diets promote growth performance of nursery pigs and affects their responses to immunological challenge.

Field trials were conducted in 2016, 2017 and 2018 with dark fire-cured, dark air-cured, and burley tobacco at Princeton, Murray and Lexington Kentucky. Tobacco variety used in 2016 was a low converter (LC) variety, varieties used in 2017 and 2018 were LC and higher converter (HC) varieties. Potassium sources used at all locations and in all years were potassium sulfate (K2SO4) and potassium chloride (KCl). Application rates used at all locations and in all years were 93, 186, 279 kg K ha-1along with an untreated control that received no potassium. In all trials, tobacco that was treated with either potassium source yielded numerically higher than the untreated control. In seven out of 10 trials, LC varieties had a higher moisture content than HC varieties. Tobacco treated with KCl had higher chloride levels than tobacco treated with K2­SO4.Quality grade index was similar for tobacco treated with KCl compared to tobacco treated with K2SO4. In all trials, tobacco treated with KCl had numerically lower Tobacco Specific Nitrosamines (TSNA) levels than tobacco treated with K2SO4. Reductions in TSNA levels were 30% lower in tobacco treated with KCl compared to tobacco treated with K2SO­4.

Currently, there exists a great deal of uncertainty regarding atmospheric aerosols and the role that they play within the Earth’s atmosphere. It is known that atmospheric aerosols can play a role in the Earth’s climate by scattering and absorbing solar radiation or acting as a cloud condensation nuclei. The purpose of this work is to obtain an improved understanding of the chemistry of atmospheric aerosols to better determine their impacts the environment, air quality, and climate. This work revolves around one specific type of atmospheric aerosol, i.e. sea spray aerosol. Sea spray aerosol is generated via breaking waves, through wind-driven mechanisms. Ocean water covers roughly 71% of the Earth’s surface, and from this over 1300 Tg of sea spray aerosols is emitted into the atmosphere every year. However, until recently, the study of sea spray was very challenging and often inconclusive due to the inability to filter background particles out. In this work, the understanding of sea spray aerosol is progressed by taking a two-pronged approach. First, this work focuses on the study of model systems of simple ocean surfactants and NaCl and the change in chemistry that occurs when the two are in the presence of each other. Second, sea spray samples generated during a biological bloom are isolated and analyzed. Using this two pronged approach, it is shown that model systems can provide supporting evidence for hypotheses created from trends discovered in more complex samples. Finally, common aerosol generation, storage, and analysis techniques are studied in order to improve our understanding of their effects on aerosol particles.

A greenhouse study was conducted to determine the effects of deposition from static rocket test fires on corn and alfalfa. Seeds were germinated in a wide concentration range of depositional material, called test fire soil (TFS). Additionally, the impact of chloride and aluminum, two major components of test fire soil, on germination was also evaluated. Furthermore, plants were grown in packed columns and exposed to test fire soil, either in the root zone or on foliage. Tissue was weighed and analyzed to compare biomass production and plant composition. Corn and alfalfa exposed to test fire soil in the root zone produced less biomass than controls, but foliar treatment had no effect on biomass production. No kernels were produced by corn exposed to test fire soil in the root zone. Leaves of plants exposed to test fire soil in the root zone accumulated more metals and nutrients than controls, whereas plant tissue treated with test fire soil on the leaves contained only elevated levels of aluminum, although levels were still within reasonable concentrations for plants. Germination of seeds was not affected below 1% test fire soil in soil; however higher concentrations of test fire soil decreased percent germination. Addition of chloride to soil also inhibits germination, but addition of aluminum has no effect on germination percentage. Corn germination was restored in test fire soil leached with 200 mm artificial rainwater. The results of this research contribute information regarding the potential impact of test fire soil from static test fires on crop production. Test fire soil inhibits germination and growth if deposited in the root zone, and even foliar application alters tissue composition. However, plant composition is not altered significantly in terms of feed criteria, and germination can be restored by irrigating the TFS. The effects of test fire soil are attributed to high levels of chloride that induce salt stress. Crop damage may be avoided by conducting static test fires after crops are harvested or providing extra irrigation to soil impacted with the TFS.

Experiment A explored the influence of sodium on direct acid, nonfat Mozzarella cheese. Cheeses with differing salt levels were obtained by varying dry salt applications (none, 0.5%, and 1.0% NaCl w/w) and hot brine stretching (0%, 5%, and 10% NaCl wt/v). Salt application and salt content influenced cheese moisture, meltability, expressible serum, micro- and ultra-structure, and color. Moisture was highest when cheese was salted before stretching (P = 0.03) . Melt was lowest in cheeses that were unsalted (P = 0.05). Cheeses stretched in salt brine had < 1% of the amount of expressible serum found in unsalted cheese (P < 0.0001). Unsalted cheeses had a more open structure with pockets of serum distributed throughout the protein matrix giving it an opaque, white appearance. Salted cheeses had a more homogeneous protein matrix lacking light scattering surfaces, resulting in a translucent cheese. Neither salt concentration nor method of salting affected the calcium content of the cheeses (P > 0.05). Experiment B explored the influence of calcium, moisture, and pH on cheese structure and functionality. Cheeses were manufactured using combinations of citric and acetic acids. Addition of EDTA to the whey during cooking, CaCl2 fortification, and extended drain times were used to produce eight cheeses in a 23 factorial design with target pH levels of 5.8 and 5.3, 70% and 66% moisture, and 0.6% and 0.3% calcium levels. EDTA was unsuccessful in removing calcium from pH 5.8 cheese. Adding CaCh successfully increased the calcium level of pH 5.3 cheese. Cheese with 0.3% calcium had greatest melt, decreased hardness and increased adhesiveness. Cheese with 0.6% calcium had decreased melt and adhesiveness, and increased hardness. When calcium content was held at 0.6% there was no significant difference in melting even when pH was varied from pH 5.8 to pH 5.3 . The microstructure of the 0.6% calcium cheeses had an increase in protein folds and serum pockets. Low calcium cheeses had a very homogeneous structure. Directly acidified nonfat Mozzarella cheese manufactured with 1.0% dry salt and hot water stretching produced the best cheese. This cheese contained 0.4% salt, 0.4% calcium, no expressible serum, and good meltability.

Orientador: Marcos David Ferreira / Resumo: Objetivo. Analisar a eficácia antimicrobiana in vitro de compósito em pó a base de prata e sua aplicação em diferentes concentrações em filmes de policloreto de vinila (PVC) produzidos em escala industrial e em laboratório. Métodos. Um material compósito constituído por dióxido de sílicio (SiO2) e nanopartículas de prata (NpAg), produzido e cedido por uma empresa de soluções tecnológicas, foi caracterizado por Microscopia Eletrônica de Varredura (MEV), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Filmes de PVC industrial aditivados com 6,25, 12,5, 25 e 100 ppm de NpAg e filmes produzidos laboratorialmente pelo método de casting aditivados com 12,5, 25 e 100 ppm de NpAg foram caracterizados por Microscopia Eletrônica de Varredura (MEV), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Testes microbiológicos in vitro foram realizados com o compósito de prata e com os filmes de PVC. Com o compósito realizou-se o Teste de Difusão em Ágar por poço e a Contagem de Microrganismos Viáveis. Com os filmes industrial e laboratorial realizou-se o teste da Norma JIS Z 2801:2000, e com os filmes industriais realizou-se os testes de Agitação em Frasco e Contagem de Microrganismos Viáveis. Resultados. O compósito apresentou inibição para Escherichia coli em todas as concentrações estudadas e para Staphylococcus aureus nas concentrações de 12,5, 25 e 100 ppm de NpAg. A adição de compósito na matriz... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Reverse Osmosis (RO) is widely accepted as an alternative method to produce freshwater from different feed water sources. This technology competitively substitutes the thermal processes in the near future because of several advantages particularly in energy saving. The success of RO operation will, however, depends largely on the overall membrane performance. Deposit or build-up of solute is one of the main reasons for membrane operation failure. Build-up of solute or deposit which is known as fouling and scaling will decrease the permeate flux and increase the energy consumption in particular after prolonged operation of RO. The thesis presents the experimental results obtained in a small-scale RO system. The aim of this study is to investigate the effect of sodium chloride and calcium carbonate on the membrane performance and subsequent build-up of solute on the membrane surface. The experiments were carried out in a small-scale of RO (2 m3/day capacity) with spiral wound membrane using simulated feed water, secondary effluent, and groundwater samples. The parameters chosen for the experiments are applied pressure (1250-4750 kPa), and concentration of sodium chloride (l00-5000 mg/L) and calcium carbonate (50-100 mg/L). / The results from feedwater runs indicated that initial sodium chloride and calcium carbonate in feed water and applied pressure affects the overall membrane performance. However, there is no significant effect on membrane performance for sodium chloride with concentration below 1200 mg/L and applied pressure lower than 2250 kPa. Applied pressure appears to have an impact on build-up of sodium and calcium on the membrane surface for pressures greater than 2750 kPa. For typical small-scale RO system used in this experiment, build-up of calcium will slightly decrease with given pressure caused by the characteristic of membrane that easily removes the divalent ions. The osmotic pressure of solution also strongly affects the permeate flow rate in particular for relatively higher sodium concentration (> 2500 mg/L). As a consequence of higher osmotic pressure, zero permeate flux is achieved when sodium chloride concentration was greater than 5000 mg/L and applied pressure lower than 1750 kPa. Results also indicated that fouling might pose a potential problem in small-scale RO operation. In order to investigate the membrane performance, experiments with secondary effluent samples were also performed. Results indicated that water recovery percentages and permeate flux also linearly increase with applied pressure. However, effectiveness of membrane decreases less than 98% otherwise build-up of solute tends to increase. It is suggested that lower values of the water recovery percentage (WRP) and permeate flux (Jw) are caused by the characteristic of secondary effluent that have high-suspended solids, organic carbon, and minerals. Further, the membrane performance also examined with ground water as feed water sample. / Results showed that both water recovery percentage and permeate flux linearly increased with operating pressure. However, intensive pretreatment are required as a result of higher concentration of humic acid and iron in raw feed. Percentages of ion rejection for sodium and calcium are greater than 98 and 99% respectively. The high ion rejections are mainly due to the characteristics of groundwater with low TDS and EC. Sodium and calcium build-up in a small-scale RO system considered appears to be affected by the applied pressure. Build-up of solute in small-scale of RO system has been predicted using the empirical model proposed in this work. Two ions namely sodium and calcium in feed water considered as predominant ions responsible for fouling and scaling on the membrane surface. Four main parameters namely, applied pressure (P), permeate flux (Jw), membrane resistance (Rm), and feed concentration (Cf) are considered which strongly affect the overall membrane performance. The empirical correlations derived from experimental observation among these parameters can be expressed as follows: In Md NaCI = O. 77 In P + 0.67 In Jw + 0.19 In Rm + 0.171n Cf In Md CaCO3= 0.96 In P + 0.75 In Jw + 0.2 In Rm - 0.07 In Cf / The empirical models proposed in this thesis may be useful for predicting the buildup of solute on the membrane surfaces. In the present work, an attempt has been made to estimate the energy consumption and unit cost for desalting of different feed water samples in a small-scale RO system. In RO plants, unit cost of water production from feed water is primarily governed by the energy required for pumping raw water. Estimates of specific energy consumption (SEC) for desalting of sodium chloride, combined sodium and calcium carbonate solutions were found to be in the range of 0.79 - 3.21 and 0.81 - 3.22 kwh/m3 respectively. For groundwater and secondary effluent, they are estimated to 0.63 - 1.71 and 0.79 - 2.02 kWh/m3 respectively. Moreover, energy consumption for different feed water samples was used to estimate the unit cost for water production. Estimation of unit costs for combined sodium chloride and calcium carbonate solution, groundwater, and secondary effluent runs are $2.06 - 3.22, $1.98 - 2.57 and $1.56- 2.66 respectively. In this work, unit cost is still higher due to greater energy consumption .by the pumping system which is required in a small-scale RO operation. Based on the experimental results, it appears that the characteristics of feed water samples affect the membrane performance and their effects must be taken into account in the design of RO units so as to reduce the unit cost for water production. / The findings from the present experimental and modelling work are of practical significance in not only providing the knowledge base in the area of desalination but also paves the way for developing tools for the prediction of build-up of solutes on membrane surface in full scale reverse osmosis operations.

Osmotic distillation is a process of removing water from an aqueous solution, driven by water vapour pressure gradient across a hydrophobic membrane. The process occurs at or below ambient temperature and under atmospheric pressure. This research project investigates the osmotic distillation process in hollow fibre modules using hollow fibres PP375, PV375 and PV660 supplied by Memcor Australia. Operating conditions such as temperature, feed concentration and brine cross flow velocity, but not the feed cross flow velocity, were found to have significant effect on the flux. Models for heat and mass transfers were used to study the polarisation phenomena in osmotic distillation. Temperature and concentration profiles at the membrane surfaces due to polarisation were quantified. Scholfield and Ordinary Diffusion models for flux prediction based on the bulk conditions were developed and validated. Models for water activity and viscosity of aqueous glucose and calcium chloride solutions were also developed and validated in this work. / Master of Science (Hons)