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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Generation Of A Novel TiO <sub>2</sub> - Composite – A Feasibility Study

Lindstrom, Mathias E.V. 23 July 2002 (has links)
No description available.
52

Diseño de alimentos saciantes: estudio de las propiedades físicas, sensoriales y de la capacidad saciante esperada en un postre lácteo sólido tipo tarta de queso

Marcano Rodríguez, Johanna María 07 October 2015 (has links)
Tesis por compendio / [EN] The main objective of this project was development of various strategies for the reformulation of satiating food. The effect of composition, physicochemical and sensory factors in a model of solid food (cheese pie), on the expectations of its satiating capacity and gastric behavior in vitro was evaluated. In a first phase, cheese pies were reformulated changing the content of its minor components in order to assess, through methods TDS and Acceptability Dynamic and Static the effect of each of these ingredients on the dynamics of the oral pathway and its relation to the expectations of satiety and acceptance. They were also evaluated, through the use of bipolar scales JAR and penalty analysis, some of the key attributes that determine cakes' acceptability on an "ideal". The cheese pies without egg and more content in powder milk had harder and dry textures that prolonged the oral exposure and increased the satiating capacity perceived without affect radically it acceptability. In a second phase, reformulations were made increasing concentrations of dairy protein and vegetable. To evaluate changes in the physical properties of the cheese pies and their effect on satiety perceived, rheological and texturometric methods and sensory technique CATA were used. The cheese pies with whey protein isolated were harder and more compact than the pies with soy protein. Soy protein conferred characteristics "unexpected" of flavor resulting in a lower acceptability and expectations of satiety. In a third step, the effect of increasing complexity in texture and appearance of cheese pies, incorporating various visible particles, on expectations of satiety was evaluated. Texturometríc method and Flash Profile technique for sensory characterization were used. Using open-ended questions the terms associated with the perception of complexity were explored. The pies with oat flakes were harder, harder to chew and obtained the highest values of expected satiating capacity. In the rest of cheese pies with particles, it was found that when the perception of complexity was greater, also the appreciation of satiating capacity was greater. In a fourth phase of the project, cheese pies were prepared incorporating increasing concentrations of konjac glucomannan (KGM) which is a soluble fiber with high viscosity. The presence of this fiber collaterally allowed the use of skimmed cheese (with the consequent elimination of all cheese fat) and the corn starch suppression. The viscoelastic behavior of pie digested under gastric conditions in vitro using rheology was evaluated. At high concentrations of KGM, radicals increases were observed in the viscoelastic components, showing the formation of a mass of solid features and could cause distention and the consequent delay of emptying gastric. Finally, sensory technique Partial Projective Maps and comparison with the Global Map were used. Different formulations obtained in the previous four phases were characterized and compared. Partial maps explored the perception of consumers to collect information about sensory modalities specific of texture and flavor separately. The results indicated that with the partial maps more detailed information was obtained, allowing consumers to focus on a smaller perceptual focus. The global map showed higher correlation with the map of flavor, indicating that consumers were focused on this method to find similarities and differences between samples, or at least found it easier, allowing differentiation between samples with more and less familiar flavors. The satiating capacity aligned with harder textures without losing recognizable traditional flavors in a cheese pie. Comparison of projective maps proved to be a very interesting design of new product categories as satiating foods. / [ES] El objetivo central de este proyecto se centró en el desarrollo de diversas estrategias para la reformulación de un alimento que resulte saciante. Se evaluó el efecto de diversos factores de composición, fisicoquímicos y sensoriales en pasteles de queso como modelo de alimento sólido, sobre las expectativas de su capacidad saciante y sobre el comportamiento gástrico in vitro. En una primera fase, se reformularon pasteles de queso modificando el contenido de sus componentes minoritarios con el objetivo de evaluar, a través de los métodos de TDS y Aceptabilidad Dinámica y Estática, el efecto de cada uno de estos ingredientes sobre la dinámica de la trayectoria oral y su relación con las expectativas de saciedad y aceptación. También se evaluaron, a través del uso de escalas bipolares JAR y análisis de penalización, algunos de los atributos clave de los pasteles que determinan su aceptabilidad respecto de un "ideal". Los pasteles sin huevo y con mayor contenido en leche en polvo resultaron con texturas más duras y secas que prolongaron su exposición oral y aumentaron la capacidad saciante percibida sin afectar radicalmente su aceptabilidad. En una segunda fase, se realizaron reformulaciones incorporando concentraciones crecientes de proteínas láctea y vegetal. Para evaluar los cambios en las propiedades físicas de los pasteles y su efecto sobre la saciedad percibida se utilizaron métodos de reología, texturometría y la técnica sensorial C.A.T.A. Los pasteles con aislado de proteína de suero lácteo resultaron más duros y compactos que los pasteles con proteína de soja. La proteína de soja confirió características de sabor "no esperadas" resultando en una menor aceptabilidad y expectativas de saciedad. En una tercera etapa, se evaluó el efecto de incrementar la complejidad en textura y apariencia de los pasteles de queso, incorporando distintas partículas visibles sobre las expectativas de saciedad. Se utilizaron texturometría y la técnica de Flash Profile para la caracterización sensorial. Mediante técnica de preguntas abiertas se exploraron los términos asociados con la percepción de complejidad. Los pasteles con copos de avena fueron más duros, difíciles de masticar y obtuvieron los mayores valores de saciedad esperada, confirmando los resultados de las fases uno y dos de la presente memoria. En el resto de los pasteles se encontró que a mayor percepción de complejidad mayor valoración de su capacidad saciante. Los pasteles con salvado de trigo, seguidos de los que contenían semillas de lino (partículas oscuras y de tamaño bien visible) se percibieron como más complejos que los pasteles con coco rallado (partículas blancas, pequeñas y bien integradas en la masa del pastel). En una cuarta fase del proyecto, se elaboraron pasteles incorporando concentraciones crecientes de glucomanano de konjac (KGM). Se evaluó el comportamiento viscoelástico de los pasteles digeridos bajo condiciones gástricas in vitro utilizando técnicas de reología instrumental. El aumento en la concentración de KGM en los pasteles de queso digeridos, incrementó gradualmente las propiedades viscoelásticas. Los pasteles formulados con KGM mostraron mayor dureza y masticabilidad instrumentales lo que evidenció beneficios adicionales ya mencionados a nivel orosensorial. En cuanto a la aceptabilidad, el ingrediente disminuyó la intensidad del sabor percibido, por lo que las futuras reformulaciones deben reorientar el sabor. Finalmente, se utilizó la técnica sensorial de Mapas Proyectivos Parciales y Global. Se caracterizaron y compararon diferentes formulaciones obtenidas en las cuatro fases anteriores. Los mapas parciales permitieron explorar la percepción de los consumidores para reunir información acerca de las modalidades sensoriales específicas de textura y sabor separadamente. La capacidad saciante se alineó con texturas más duras pero sin perder sabores tradicionales reconocibles en un pa / [CA] L'objectiu central d'aquest projecte es va centrar en el desenvolupament de diverses estratègies per a la reformulació d'un aliment que resulte saciant. Es va avaluar l'efecte de diversos factors de composició, fisicoquímics i sensorials en pastissos de formatge com a model d'aliment sòlid, sobre les expectatives de la seua capacitat saciant i sobre el comportament gàstric in vitro.En una primera fase, es van reformular pastissos de formatge modificant el contingut dels seus components minoritaris amb l'objectiu d'avaluar, a través dels mètodes de TDS i Acceptabilitat Dinàmica i Estàtica, l'efecte de cadascun d'aquests ingredients sobre la dinàmica de la trajectòria oral i la seua relació amb les expectatives de sacietat i acceptació. També es van avaluar, a través de l'ús d'escales bipolars JAR i anàlisis de penalització, alguns dels atributs clau dels pastissos que determinen la seua acceptabilitat respecte d'un "ideal". Els pastissos sense ou i amb major contingut en llet en pols van resultar amb textures més dures i seques que van perllongar la seua exposició oral i van augmentar la capacitat saciant percebuda sense afectar radicalment la seua acceptabilitat. En una segona fase, es van realitzar reformulacions incorporant concentracions creixents de proteïnes làctiques i vegetal. Per a avaluar els canvis en les propietats físiques dels pastissos i el seu efecte sobre la sacietat percebuda es van utilitzar mètodes de reologia, textura i la tècnica sensorial C.A.T.A. Els pastissos amb aïllat de proteïna de sèrum làctic van resultar més durs i compactes que els pastissos amb proteïna de soia. La proteïna de soia va conferir característiques de sabor "no esperades" resultant en una menor acceptabilitat i expectatives de sacietat. En una tercera etapa, es va avaluar l'efecte d'incrementar la complexitat en textura i aparença dels pastissos de formatge, incorporant diferents partícules visibles, sobre les expectatives de sacietat. Es van utilitzar texturometria i la tècnica de Flash Profile per a la caracterització sensorial. Mitjançant tècnica de preguntes obertes es van explorar els termes associats amb la percepció de complexitat. Els pastissos amb flocs de civada van ser més durs, difícils de mastegar i van obtenir els majors valors de sacietat esperada, confirmant els resultats de les fases un i dues de la present memòria. En la resta dels pastissos, es va trobar que a major percepció de complexitat major valoració de la seua capacitat saciant. En una quarta fase del projecte, es van elaborar pastissos incorporant concentracions creixents de glucomanan de konjac (KGM). Es va avaluar el comportament viscoelàstic dels pastissos digerits sota condicions gàstriques in vitro utilitzant tècniques de reologia instrumental. L'augment en la concentració de KGM en els pastissos de formatge digerits, va incrementar gradualment les propietats viscoelàstiques. D'altra banda, els pastissos formulats amb KGM van mostrar major duresa i mastegabilitat instrumentals el que va evidenciar beneficis addicionals ja esmentats a nivell oro-sensorial. Respecte a l'acceptabilitat, l'ingredient va disminuir la intensitat del sabor percebut, per la qual cosa les futures reformulacions han de reorientar el sabor. Finalment, es va utilitzar la tècnica sensorial de Mapes Projectius Parcials i Global. Es van caracteritzar i van comparar diferents formulacions obtingudes en les quatre fases anteriors. Els mapes parcials van permetre explorar la percepció dels consumidors per a reunir informació sobre les modalitats sensorials específiques de textura i sabor separadament. La capacitat saciant es va alinear amb textures més dures però sense perdre sabors tradicionals reconeguts en un pastís de formatge. La comparació de mapes projectius va resultar ser una aportació integradora molt interessant en el disseny de noves categories de productes com els aliments saciants. / Marcano Rodríguez, JM. (2015). Diseño de alimentos saciantes: estudio de las propiedades físicas, sensoriales y de la capacidad saciante esperada en un postre lácteo sólido tipo tarta de queso [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/55683 / Compendio
53

Investigation into the occurrence of the dinoflagellate, Ceratium hirundinella in source waters and the impact thereof on drinking water purification / van der Walt N.

Van der Walt, Nicolene January 2011 (has links)
The Ceratium species occurring in the Vaal River since 2000, was identified as Ceratium hirundinella (O.F. Müller) Dujardin as proposed by Van Ginkel et al (2001). Ceratium hirundinella is known to cause problems in drinking water purification and has been penetrating into the final drinking water of Rand Water since 2006. Ceratium hirundinella is associated with many other water purification problems such as disrupting of the coagulation and flocculation processes, blocking of sand filters and algal penetration into the drinking water. Ceratium hirundinella also produce fishy taste and odorous compounds and causes discolouration of the water. The aims of this study were to determine the main environmental factors which are associated with the bloom formation of C. hirundinella in the source water and to investigate the influence of C. hirundinella on the production of potable water. In order to optimise treatment processes and resolve problems associated with high C. hirundinella concentrations during the production of potable water, jar testing and chlorine exposure experiments were performed. Multivariate statistical analyses were performed to determine the main environmental variables behind C. hirundinella blooms. Ten years data (2000 - 2009) from the sampling point C–VRB5T in the Vaal River, (5 km upstream from the Barrage weir) were used for this investigation, because C. hirundinella occurred there frequently during the ten year period. In this study, it was found that C. hirundinella was favoured by high pH, Chemical Oxygen Demand (COD), orthophoshapte (PO4), and silica concentrations, as well as low turbidity and low dissolved inorganic nitrogen (DIN) concentrations. No correlation was found between C. hirundinella and temperature, suggesting that this alga does not occur during periods of extreme warm or extreme cold conditions, but most probably during autumn and spring. The results of the multivariate statistical analysis performed with historical data from Vaalkop dam, indicate that the dinoflagellate C. hirundinella seems to be favoured by low temperature and turbidity, and high DIN, Fe, Methyl–orange alkalinity, Cd, PO4, Conductivity, pH, hardness and SO4 concentrations. In order to optimise treatment processes such as coagulation, flocculation and sedimentation, jar testing experiments were performed to investigate different coagulant chemicals namely: cationic poly–electrolyte only, cationic poly–electrolyte in combination with slaked lime (CaO) and CaO in combination with activated silica. Water from four different sampling localities were chosen to perform the different jar testing experiments: 1) sampling point M–FOREBAY (in the Forebay, connecting the canal to the Zuikerbosch Purification plant) near Vereeniging due to its proximity to the Zuikerbosch treatment plant, 2) M–CANAL_VD (upstream from the inflow of the recovered water from Panfontein) to determine the influence of (if any) the recovered water from Panfontein on Forebay source water, 3) source water from Vaalkop Dam (M–RAW_VAALKOP) and 4) source water from Rietvlei Dam (water from both Vaalkop and Rietvlei Dams contained high concentrations of C. hirundinella at that time of sampling) to determine which coagulant chemical is the most effective in removing high concentrations of C. hirundinella cells during the production of drinking water. The jar testing experiments with Vaalkop Dam and Rietvlei Dam source water (rich with C. hirundinella) indicated that using cationic poly–electrolyte alone did not remove high concentrations of C. hirundinella efficiently. However, when CaO (in combination with cationic poly–electrolyte or activated silica) were dosed to Vaalkop Dam source water a significant decrease of C. hirundinella concentration was observed. This indicates that the C. hirundinella cells were “shocked or stressed” when exposed to the high pH of the CaO, rendering it immobile and thereby enhancing the coagulation and flocculation process. However, when 10 mg/L CaO in combination with poly–electrolyte was dosed to Rietvlei Dam source water the turbidity and chlorophyll–665 results indicated that this coagulant chemical procedure was ineffective in removing algal material from the source water. The jar testing experiments using the cationic poly–electrolyte alone or cationic poly–electrolyte in combination with CaO on M–FOREBAY and M–CANAL_VD source water, showed a decrease in turbidity, chlorophyll–665 concentration, and total algal biomass, with an increase of coagulant chemical. When CaO in combination with activated silica was dosed, the inherent turbidity of the lime increased the turbidity of the Vaalkop Dam, M–FOREBAY and M–CANAL_VD source water to such an extent that it affected coagulation negatively, resulting in high turbidity values in the supernatant. Regardless of the turbidity values, the chlorophyll–665 concentration and total algal biomass (C. hirundinella specifically in Vaalkop Dam source water) decreased significantly when CaO was dosed in combination with activated silica. Therefore it was concluded that a cationic poly–electrolyte alone is a good coagulant chemical for the removal of turbidity, but when high algal biomass occur in the source water it is essential to add CaO to “stress” or “shock” the algae for the effective removal thereof. However, when CaO in combination with activated silica was dosed to Rietvlei Dam source water a decrease in turbidity and chlorophyll–665 concentration was found with an increasing coagulant chemical concentration. These results confirm the fact that coagulant chemicals may perform differently during different periods of the year when water chemistry changes and that certain coagulant chemicals may never be suitable to use for certain source waters. For the effective removal of algae during water purification, it is recommended that cationic poly–electrolyte in combination with CaO are used as coagulant chemical at the Zuikerbosch Water Purification Plant. Turbidity is not a good indication of algal removal efficiency during jar testing experiments. If problems with high algal concentrations in the source water are experienced it is advisable to also determine the chlorophyll–665 concentrations of the supernatant water during the regular jar testing experiments, since it will give a better indication of algal removal. Chlorine exposure experiments were performed on water from Vaalkop Dam (M–RAW_VAALKOP) and Rietvlei Dam source water, to determine the possibility of implementing pre– or intermediate chlorination with the aim to render the cells immobile for more effective coagulation. The chlorine exposure experiments with Vaalkop Dam and Rietvlei Dam source water showed similar results. The chlorine concentration to be dosed as part of pre– or intermediate chlorination will differ for each type of source water as the chemical and biological composition of each water body are unique. When the effect of chlorine on the freshwater dinoflagellate C. hirundinella was investigated, it was found that the effective chlorine concentration where 50 % of Ceratium cells were rendered immobile (EC50) was approximately 1.16 mg/L for Vaalkop Dam source water. For the source water sampled from Rietvlei Dam, it was found that the EC50 was at approximately 0.87 mg/L. Results of analyses to determine the organic compounds in the water after chlorination revealed that an increase in chlorine concentration resulted in increase in total organic carbon concentration (TOC), as well as a slight increase in MIB and trihalomethanes (CHCl3). Pre– or intermediate chlorination seem to be an effective treatment option for the dinoflagellate C. hirundinella to be rendered immobile and thereby assisting in its coagulation process. The use of pre– or intermediate chlorination to effectively treat source waters containing high concentrations of C. hirundinella is a viable option to consider. However, the organic compounds in the water should be monitored and the EC50 value for each source water composition should be determined carefully as to restrict cell lysis and subsequent release of organic compounds into the water. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2012.
54

Investigation into the occurrence of the dinoflagellate, Ceratium hirundinella in source waters and the impact thereof on drinking water purification / van der Walt N.

Van der Walt, Nicolene January 2011 (has links)
The Ceratium species occurring in the Vaal River since 2000, was identified as Ceratium hirundinella (O.F. Müller) Dujardin as proposed by Van Ginkel et al (2001). Ceratium hirundinella is known to cause problems in drinking water purification and has been penetrating into the final drinking water of Rand Water since 2006. Ceratium hirundinella is associated with many other water purification problems such as disrupting of the coagulation and flocculation processes, blocking of sand filters and algal penetration into the drinking water. Ceratium hirundinella also produce fishy taste and odorous compounds and causes discolouration of the water. The aims of this study were to determine the main environmental factors which are associated with the bloom formation of C. hirundinella in the source water and to investigate the influence of C. hirundinella on the production of potable water. In order to optimise treatment processes and resolve problems associated with high C. hirundinella concentrations during the production of potable water, jar testing and chlorine exposure experiments were performed. Multivariate statistical analyses were performed to determine the main environmental variables behind C. hirundinella blooms. Ten years data (2000 - 2009) from the sampling point C–VRB5T in the Vaal River, (5 km upstream from the Barrage weir) were used for this investigation, because C. hirundinella occurred there frequently during the ten year period. In this study, it was found that C. hirundinella was favoured by high pH, Chemical Oxygen Demand (COD), orthophoshapte (PO4), and silica concentrations, as well as low turbidity and low dissolved inorganic nitrogen (DIN) concentrations. No correlation was found between C. hirundinella and temperature, suggesting that this alga does not occur during periods of extreme warm or extreme cold conditions, but most probably during autumn and spring. The results of the multivariate statistical analysis performed with historical data from Vaalkop dam, indicate that the dinoflagellate C. hirundinella seems to be favoured by low temperature and turbidity, and high DIN, Fe, Methyl–orange alkalinity, Cd, PO4, Conductivity, pH, hardness and SO4 concentrations. In order to optimise treatment processes such as coagulation, flocculation and sedimentation, jar testing experiments were performed to investigate different coagulant chemicals namely: cationic poly–electrolyte only, cationic poly–electrolyte in combination with slaked lime (CaO) and CaO in combination with activated silica. Water from four different sampling localities were chosen to perform the different jar testing experiments: 1) sampling point M–FOREBAY (in the Forebay, connecting the canal to the Zuikerbosch Purification plant) near Vereeniging due to its proximity to the Zuikerbosch treatment plant, 2) M–CANAL_VD (upstream from the inflow of the recovered water from Panfontein) to determine the influence of (if any) the recovered water from Panfontein on Forebay source water, 3) source water from Vaalkop Dam (M–RAW_VAALKOP) and 4) source water from Rietvlei Dam (water from both Vaalkop and Rietvlei Dams contained high concentrations of C. hirundinella at that time of sampling) to determine which coagulant chemical is the most effective in removing high concentrations of C. hirundinella cells during the production of drinking water. The jar testing experiments with Vaalkop Dam and Rietvlei Dam source water (rich with C. hirundinella) indicated that using cationic poly–electrolyte alone did not remove high concentrations of C. hirundinella efficiently. However, when CaO (in combination with cationic poly–electrolyte or activated silica) were dosed to Vaalkop Dam source water a significant decrease of C. hirundinella concentration was observed. This indicates that the C. hirundinella cells were “shocked or stressed” when exposed to the high pH of the CaO, rendering it immobile and thereby enhancing the coagulation and flocculation process. However, when 10 mg/L CaO in combination with poly–electrolyte was dosed to Rietvlei Dam source water the turbidity and chlorophyll–665 results indicated that this coagulant chemical procedure was ineffective in removing algal material from the source water. The jar testing experiments using the cationic poly–electrolyte alone or cationic poly–electrolyte in combination with CaO on M–FOREBAY and M–CANAL_VD source water, showed a decrease in turbidity, chlorophyll–665 concentration, and total algal biomass, with an increase of coagulant chemical. When CaO in combination with activated silica was dosed, the inherent turbidity of the lime increased the turbidity of the Vaalkop Dam, M–FOREBAY and M–CANAL_VD source water to such an extent that it affected coagulation negatively, resulting in high turbidity values in the supernatant. Regardless of the turbidity values, the chlorophyll–665 concentration and total algal biomass (C. hirundinella specifically in Vaalkop Dam source water) decreased significantly when CaO was dosed in combination with activated silica. Therefore it was concluded that a cationic poly–electrolyte alone is a good coagulant chemical for the removal of turbidity, but when high algal biomass occur in the source water it is essential to add CaO to “stress” or “shock” the algae for the effective removal thereof. However, when CaO in combination with activated silica was dosed to Rietvlei Dam source water a decrease in turbidity and chlorophyll–665 concentration was found with an increasing coagulant chemical concentration. These results confirm the fact that coagulant chemicals may perform differently during different periods of the year when water chemistry changes and that certain coagulant chemicals may never be suitable to use for certain source waters. For the effective removal of algae during water purification, it is recommended that cationic poly–electrolyte in combination with CaO are used as coagulant chemical at the Zuikerbosch Water Purification Plant. Turbidity is not a good indication of algal removal efficiency during jar testing experiments. If problems with high algal concentrations in the source water are experienced it is advisable to also determine the chlorophyll–665 concentrations of the supernatant water during the regular jar testing experiments, since it will give a better indication of algal removal. Chlorine exposure experiments were performed on water from Vaalkop Dam (M–RAW_VAALKOP) and Rietvlei Dam source water, to determine the possibility of implementing pre– or intermediate chlorination with the aim to render the cells immobile for more effective coagulation. The chlorine exposure experiments with Vaalkop Dam and Rietvlei Dam source water showed similar results. The chlorine concentration to be dosed as part of pre– or intermediate chlorination will differ for each type of source water as the chemical and biological composition of each water body are unique. When the effect of chlorine on the freshwater dinoflagellate C. hirundinella was investigated, it was found that the effective chlorine concentration where 50 % of Ceratium cells were rendered immobile (EC50) was approximately 1.16 mg/L for Vaalkop Dam source water. For the source water sampled from Rietvlei Dam, it was found that the EC50 was at approximately 0.87 mg/L. Results of analyses to determine the organic compounds in the water after chlorination revealed that an increase in chlorine concentration resulted in increase in total organic carbon concentration (TOC), as well as a slight increase in MIB and trihalomethanes (CHCl3). Pre– or intermediate chlorination seem to be an effective treatment option for the dinoflagellate C. hirundinella to be rendered immobile and thereby assisting in its coagulation process. The use of pre– or intermediate chlorination to effectively treat source waters containing high concentrations of C. hirundinella is a viable option to consider. However, the organic compounds in the water should be monitored and the EC50 value for each source water composition should be determined carefully as to restrict cell lysis and subsequent release of organic compounds into the water. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2012.
55

The Effect of Selected Coagulants on Chloride-to-Sulfate Mass Ratio for Lead Control and on Organics Removal in Two Source Waters

El Henawy, Walid January 2009 (has links)
Lead is a known toxin, with the ability to accumulate in the human body from as early as fetal development. Lead exposure is known to cause a myriad of health effects which are more prominent among children. Health effects upon exposure can range from renal and heart disease or potentially cancer in adults to neurotoxicity in children. The continued presence of old lead service lines and plumbing in distribution systems as well as lead-containing solders and brass fixtures in homes may contribute lead to drinking water. Recent studies have highlighted the importance of a predictor known as the chloride-to-sulfate mass ratio (CSMR) in controlling lead release. A ratio above 0.5 – 0.6 theoretically increases the aggressiveness of lead leaching in galvanic settings, while a lower ratio controls lead corrosion. A switch in coagulant type could significantly alter the ratio. However, a coagulant switch could also trigger changes in finished water turbidity and organics, including disinfection by-product (DBP) precursors, as well as impact sludge production. Anecdotal evidence from an Ontario water treatment utility suggested the potential applicability of a newly formulated polymer, cationic activated silica (CAS), in improving DBP precursor removal when used in concurrence with a primary coagulant. No previous scientific research had been dedicated to testing of the polymer. The present research had three primary objectives: The first was to investigate the effect of conventional coagulation with six different coagulants on the chloride-to-sulfate mass ratio as it pertains to lead corrosion in two Ontario source waters of differing quality. Additionally, the effect of coagulant choice on pH, turbidity, and organics removal was investigated. The second objective was aimed at testing potential reductions in CSMR and organics that could be brought about by the use of two polymers, cationic and anionic activated silica (CAS and AAS, respectively), as flocculant aids. Finally, the performance of a high-rate sand-ballasted clarification process was simulated at bench-scale to gauge its performance in comparison with conventional coagulation simulation techniques. The first series of jar-tests investigated the effectiveness of CAS as a primary coagulant on Lake Ontario water. In comparison with the conventional coagulants aluminum sulfate and polyaluminum chloride, CAS did not offer any apparent advantage with respect to turbidity and organics removal. Testing of CAS and AAS as flocculant aids was also conducted. Results from a full factorial experiment focused on CAS testing on Lake Ontario water showed that coagulant dose is the most significant contributor to CSMR, turbidity, DOC removal, and THM control. Generally, improvements resulting from CAS addition were of small magnitude (<15%). Reductions in CSMR were attributed to the presence of the sulfate-containing chemicals alum and sulfuric acid in the CAS formulation. Testing of sulfuric acid-activated AAS on Grand River water showed that pairing of AAS with polyaluminum chloride provides better results than with alum with respect to DOC removal (39% and 27% respectively at 60 mg/L coagulant dose). Highest turbidity removals (>90%) with both coagulants were achieved at the tested coagulant and AAS doses of 10 mg/L and 4 mg/L respectively. CSMR reductions in the presence of AAS were also attributable to sulfate contribution from sulfuric acid. Bench-scale simulation of a high-rate sand-ballasted clarification process on Grand River water showed comparable removal efficiencies for turbidity (80 – 90% at 10 mg/L), and DOC (30 – 40% at 50 mg/L). Finally, six different coagulants were tested on the two source waters for potential applicability in CSMR adjustment in the context of lead corrosion. The two chloride-containing coagulants polyaluminum chloride and aluminum chlorohydrate increased CSMR in proportion to the coagulant dose added, as would be expected. Average chloride contribution per 10 mg/L coagulant dose was 2.7 mg/L and 2.0 mg/L for polyaluminum chloride and aluminum chlorohydrate, respectively. Sulfate-contributing coagulants aluminum sulfate, ferric sulfate, pre-hydroxylated aluminum sulfate, and polyaluminum silicate sulfate reduced CSMR as coagulant dose increased, also as would be expected. The highest sulfate contributors per 10 mg/L dose were pre-hydroxylated aluminum sulfate (6.2 mg/L) and ferric sulfate (6.0 mg/L). The lowest CSMR achieved was 0.6 in Lake Ontario water at a 30 mg/L dose and 0.8 in Grand River water at a 60 mg/L dose. Highest DOC removals were achieved with the chloride-containing coagulants in both waters (35 – 50%) with aluminum chlorohydrate showing superiority in that respect. DOC removals with sulfate-containing coagulants were less, generally in the range of 22 – 41%. Specificity of critical CSMR values to source water needs to be investigated. Additionally, long term effects of sustained high or low CSMR values in distribution systems need to be further looked into. Finally, the effect of interventions to alter CSMR on other water quality parameters influencing lead corrosion such as pH and alkalinity still represent a research deficit.
56

The Effect of Selected Coagulants on Chloride-to-Sulfate Mass Ratio for Lead Control and on Organics Removal in Two Source Waters

El Henawy, Walid January 2009 (has links)
Lead is a known toxin, with the ability to accumulate in the human body from as early as fetal development. Lead exposure is known to cause a myriad of health effects which are more prominent among children. Health effects upon exposure can range from renal and heart disease or potentially cancer in adults to neurotoxicity in children. The continued presence of old lead service lines and plumbing in distribution systems as well as lead-containing solders and brass fixtures in homes may contribute lead to drinking water. Recent studies have highlighted the importance of a predictor known as the chloride-to-sulfate mass ratio (CSMR) in controlling lead release. A ratio above 0.5 – 0.6 theoretically increases the aggressiveness of lead leaching in galvanic settings, while a lower ratio controls lead corrosion. A switch in coagulant type could significantly alter the ratio. However, a coagulant switch could also trigger changes in finished water turbidity and organics, including disinfection by-product (DBP) precursors, as well as impact sludge production. Anecdotal evidence from an Ontario water treatment utility suggested the potential applicability of a newly formulated polymer, cationic activated silica (CAS), in improving DBP precursor removal when used in concurrence with a primary coagulant. No previous scientific research had been dedicated to testing of the polymer. The present research had three primary objectives: The first was to investigate the effect of conventional coagulation with six different coagulants on the chloride-to-sulfate mass ratio as it pertains to lead corrosion in two Ontario source waters of differing quality. Additionally, the effect of coagulant choice on pH, turbidity, and organics removal was investigated. The second objective was aimed at testing potential reductions in CSMR and organics that could be brought about by the use of two polymers, cationic and anionic activated silica (CAS and AAS, respectively), as flocculant aids. Finally, the performance of a high-rate sand-ballasted clarification process was simulated at bench-scale to gauge its performance in comparison with conventional coagulation simulation techniques. The first series of jar-tests investigated the effectiveness of CAS as a primary coagulant on Lake Ontario water. In comparison with the conventional coagulants aluminum sulfate and polyaluminum chloride, CAS did not offer any apparent advantage with respect to turbidity and organics removal. Testing of CAS and AAS as flocculant aids was also conducted. Results from a full factorial experiment focused on CAS testing on Lake Ontario water showed that coagulant dose is the most significant contributor to CSMR, turbidity, DOC removal, and THM control. Generally, improvements resulting from CAS addition were of small magnitude (<15%). Reductions in CSMR were attributed to the presence of the sulfate-containing chemicals alum and sulfuric acid in the CAS formulation. Testing of sulfuric acid-activated AAS on Grand River water showed that pairing of AAS with polyaluminum chloride provides better results than with alum with respect to DOC removal (39% and 27% respectively at 60 mg/L coagulant dose). Highest turbidity removals (>90%) with both coagulants were achieved at the tested coagulant and AAS doses of 10 mg/L and 4 mg/L respectively. CSMR reductions in the presence of AAS were also attributable to sulfate contribution from sulfuric acid. Bench-scale simulation of a high-rate sand-ballasted clarification process on Grand River water showed comparable removal efficiencies for turbidity (80 – 90% at 10 mg/L), and DOC (30 – 40% at 50 mg/L). Finally, six different coagulants were tested on the two source waters for potential applicability in CSMR adjustment in the context of lead corrosion. The two chloride-containing coagulants polyaluminum chloride and aluminum chlorohydrate increased CSMR in proportion to the coagulant dose added, as would be expected. Average chloride contribution per 10 mg/L coagulant dose was 2.7 mg/L and 2.0 mg/L for polyaluminum chloride and aluminum chlorohydrate, respectively. Sulfate-contributing coagulants aluminum sulfate, ferric sulfate, pre-hydroxylated aluminum sulfate, and polyaluminum silicate sulfate reduced CSMR as coagulant dose increased, also as would be expected. The highest sulfate contributors per 10 mg/L dose were pre-hydroxylated aluminum sulfate (6.2 mg/L) and ferric sulfate (6.0 mg/L). The lowest CSMR achieved was 0.6 in Lake Ontario water at a 30 mg/L dose and 0.8 in Grand River water at a 60 mg/L dose. Highest DOC removals were achieved with the chloride-containing coagulants in both waters (35 – 50%) with aluminum chlorohydrate showing superiority in that respect. DOC removals with sulfate-containing coagulants were less, generally in the range of 22 – 41%. Specificity of critical CSMR values to source water needs to be investigated. Additionally, long term effects of sustained high or low CSMR values in distribution systems need to be further looked into. Finally, the effect of interventions to alter CSMR on other water quality parameters influencing lead corrosion such as pH and alkalinity still represent a research deficit.
57

The role of Archaeology in the Jesus industry

Dyer, Jennifer 12 1900 (has links)
The question leading to this study is whether the facts and theories pertaining to the Bible and Jesus Story as presented by The Authors (H Schonfield, D Joyce, B Thiering, M Baigent, R Leigh, H Lincoln; M Starbird, and D Brown) could be verified by the Archaeology evidence. I have adopted a multidiscipline and holistic approach considering information gathered from all media sources to ascertain what theories, if any could replace the traditional Jesus Story of the New Testament. I considered whether the alternative theories or traditional theories were believable due to the evidence presented by Biblical Archaeology or by the techniques used by The Authors in presenting their facts. By using Thouless’ system of Straight and Crooked thinking I was able to ascertain that the theories used in the novels written by The Authors may have been persuasive, but lacked substance. / Biblical and Ancient Studies / M. Th. (Biblical Archaeology)

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