Dissertations / Theses on the topic 'Flax oil'

Background, Consumption of marine-based oils high in omega-3 polyunsaturated fatty acids (n3PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is known to protect against obesity-related pathologies. It is less clear whether traditional vegetable oils with high omega-6 polyunsaturated fatty acid (n6PUFA) content exhibit similar therapeutic benefits. As such, this study examined the metabolic effects of a plant-based n3PUFA, stearidonic acid (SDA), in polygenic obese rodents. Methods, Lean (LZR) and obese Zucker (OZR) rats were provided either a standard westernized control diet (CON) with a high n6PUFA to n3PUFA ratio (i.e., 16.2/1.0) or experimental diet modified with flaxseed (FLAX), menhaden (FISH), or SDA oil that resulted in n6PUFA to n3PUFA ratios of 1.7/1.0, 1.3/1.0, and 1.0/0.8, respectively. Results, After 12 weeks, total adiposity, dyslipidemia, glucose intolerance, and hepatic steatosis were all greater, whereas n3PUFA content in liver, adipose, and muscle was lower in OZR vs. LZR rats. Obese rodents fed modified FISH or SDA diets had lower serum lipids and hepatic fat content vs. CON. The omega-3 index (i.e., ÓEPA + DHA in erythrocyte membrane) was 4.0, 2.4, and 2.0-fold greater in rodents provided FISH, SDA, and FLAX vs. CON diet, irrespective of genotype. Total hepatic n3PUFA and DHA was highest in rats fed FISH, whereas both hepatic and extra-hepatic EPA was higher with FISH and SDA groups. Conclusions, these data indicate that SDA oil represents a viable plant-derived source of n3PUFA, which has therapeutic implications for several obesity-related pathologies.

Three oil crops, chia (Salvia hispanica L.), flax (Linum usitatissimum L.), and castor (Ricinus communis L.), were studied because of their nutritional and industrial values. Chia and flax are rich in an ω3 fatty acid, α-linolenic acid, and castor is a very high oil producer and high in a hydroxy fatty acid. Ethyl methanesulfonate (EMS) and gamma rays were employed to mutagenize chia seeds to produce early flowering mutants. The M1 population was grown and induced to flower by short-day photoperiods. The M2 population was planted in the field in Lexington, KY in 2008. Early flowering plants were found 55 days after planting while non-mutagenized plants did not produce any flower buds until the 7th of October, 82 days after planting, at a daylength of 11 hours and 32 minutes. 0.012% of the EMS-treated M2 population and 0.024% of the gamma radiation-treated population flowered much earlier than the controls. M3 early flowering mutant lines were able to flower at photoperiods of 12-15 hours in a greenhouse. Selected lines produced flower buds on the 7th of July, 47 days after planting, at a daylength of 14 hours and 41 minutes in the field in Lexington, Kentucky. Different varieties of flax were evaluated for seed yield and field performance in Kentucky. Plant height and yield data were collected from three growing seasons. Yields from 2006 trial varied from 368-1,267 kg/ha. Yields from 2007 and 2008 were much lower due to drought. The variety ‘Carter’ gave the highest yield every season. Flax can be grown in Kentucky but yields are low. Two high-yield castor varieties, ‘Carmencita’ and ‘TTU-LRC’, were crossed in greenhouse. The F1 population was grown in the field. Inflorescences were covered to ensure self-pollination. The F2 population showed a high degree of segregation for plant height, stem color, capsule color and seed yield in the following growing season. Data on plant height, number of branches, color, and yield was collected from 89 F2 individuals. Fifteen lines with the highest yield were selected to plant in the field in spring of 2009. New high-yield castor varieties are being developed for production in Kentucky.

It is well established that replacing dietary saturated fatty acids with unsaturated fatty acids reduces cardiovascular disease (CVD) risk. Although epidemiological and clinical evidence indicate health benefits of consuming various fatty acid classes including n-9, n-6, and short- and longer-chain n-3 fatty acids, current dietary recommendations fall short of providing the optimal amounts of these fatty acids in daily diets. In addition, significant knowledge gaps remain in our understanding of the effects of, and mechanisms underpinning the action of, the various fatty acid classes on risk factors for CVD. The objective of this research was to contribute to the evaluation of health benefits of using different dietary oils, and determine how these benefits may play a role in improving public health and decreasing CVD risk. Additionally, this research examined effects of diet-gene interactions, endogenous fatty acid ethanolamides (FAEs) on body fat mass distribution as well as changes in the composition of gut microbiota following consumption of dietary oil treatments. The Canola Oil Multicenter Intervention Trial (COMIT) was conducted as a 5-phase randomized, controlled, double-blind, cross-over clinical trial. Each 4-wk treatment period was separated by 4-wk washout intervals. A total of 130 volunteers with abdominal obesity consumed each of 5 identical weight-maintaining, fixed-composition diets with one of the following treatment oils (60 g/3000 kcal) in the form of beverages: 1) conventional canola oil (Canola; n-9 rich), 2) high–oleic acid canola oil with docosahexaenoic acid (CanolaDHA; n-9 and n-3 rich), 3) a blend of corn and safflower oil (25:75) (CornSaff; n-6 rich), 4) a blend of flax and safflower oils (60:40) (FlaxSaff; n-6 and short-chain n-3 rich), and 5) high–oleic acid canola oil (CanolaOleic; highest in n-9). At endpoints, plasma fatty acid levels reflected the differences in fatty acid composition of five dietary treatments. All diets lowered total cholesterol (TC) compared with baseline. TC was lowest after the FlaxSaff phase and highest after CanolaDHA. The CanolaDHA treatment improved HDL-C, triglycerides, and blood pressure thereby reducing Framingham risk scores compared with other oils varying in unsaturated fatty acid composition. Homozygotes minor allele carriers of rs174583 (TT) on FADS2 gene showed lower (P<0.01) plasma EPA and DPA levels across all diets, but no differences were observed in DHA concentrations after the CanolaDHA feeding. In addition, plasma FAE levels were positively associated with plasma fatty acid profiles. Minor allele A carriers of rs324420 of FAAH gene showed a higher (P<0.05) plasma FAE levels compared with major allele C carriers across all diets, and showed higher (P=0.0002) docosahexaenoylethanolamide levels in response to the CanolaDHA diet. Impacts of consuming 60 g of five dietary oil treatments on gut microbiota composition were relatively minor at the phylum level and mainly at the genus level, while BMI contributed to a significant shift at the phylum level. In conclusion, consumption of a novel DHA-enriched canola oil improved blood lipid profile and largely reduced CVD risk. Diet-gene interactions might help identify sub-populations who appear to benefit from increased consumption of DHA and oleic acid. The metabolic and physiological responses to dietary fatty acids may be influenced via circulating FAEs, while the altered microbiota profile by shifts in MUFA and/or PUFA may be associated with specific physiological effect. Personalized diets varying in unsaturated fatty acids composition based on specific lifestyles, environmental factors, psychosocial factors, and genetic make-ups will become the future “healthy eating” recommendations to prevent CVD risk.
May 2016

Dissertação de Mestrado em Engenharia Zootécnica/Produção Animal
Atualmente, a nível mundial, configura-se a perspetiva de um aumento de consumo de insetos tanto pelos humanos como pelos animais, pelo que se considera importante a realização de diferentes estudos, nomeadamente da sua utilização nas dietas animais. Com o objetivo de comparar o efeito do uso de duas gorduras suplementadas na dieta de coelhos, nomeadamente de origem animal e vegetal (óleo de Hermetia illucens, e de linho, respetivamente), foram formulados 4 regimes alimentares com teor baixo (5%) e com teor alto (8%) de gordura, para cada fonte de gordura adicionada, e distribuídos a 48 coelhos (12 x 4) com 35 dias (recém desmamados) alojados em gaiolas de digestibilidade. Os animais tiveram acesso ad libitum a alimento e água durante as 5 semanas do perído experimental, sendo abatidos aos 70 dias de idade. Foram avaliados os resultados zootécnicos, sem diferenças significativas (P>0,05) e recolhidas e analisadas as fezes na 4ª semana do ensaio, para se avaliar a digestibilidade aparente das dietas. Os pesos iniciais (1047g) foram uniformes e os finais (2405g) foram semelhantes em todos os grupos. Verificou-se que há um efeito muito significativo na natureza da gordura (P<0,0001), na digestibilidade da matéria seca e na da matéria orgânica. Os regimes com óleo de insetos têm uma digestibilidade da MS e da MO cerca de 95% da digestibilidade das mesmas frações dos regimes com óleo de linho. Também a digestibilidade das frações EE e EB foi significativamente mais baixa (P<0,05) nos regimes com óleo de inseto. Os regimes com teores de gordura mais altos aumentaram a digestibilidade (P<0,0001) do extracto etéreo, mas diminuíram (P<0,003) a digestibilidade da celulose. Foram analisadas as carcaças, e não houveram diferenças significativas (P>0,05) nos pesos do aparelho digestivo, fígado, gorduras peri-renal e inter-escapular, apenas um efeito no peso do estômago vazio (P=0,006), maior nos regimes com óleo de insetos, provavelmente devido a uma maior retenção de alimento durante o período experimental. Entre os resultados colorimétricos obtidos, não parecem haver diferenças significativas, excepto uma tonalidade mais vermelha na carne dos animais dos regimes com óleo de insetos (P=0,047). De acordo com estes resultados a gordura de insetos pode ser utilizada na alimentação do coelho, apenas com alguma perda na digestibilidade da matéria seca e orgânica, mas não afetando o crescimento nem o rendimento da carcaça.
ABSTRACT - Use of alternative foods in the rabbit diet: insect oil vs flax oil - Currently, the world-wide perspective is an increase in the consumption of insects by both humans and animals. Therefore, it is considered important to carry out different studies including their use in animal diets. In order to compare the effect of two fat supplements on the rabbit diet, from animal and vegetable origin (Hermetia illucens oil, and flax/lindseed oil, respectively), four dietary regimens with low (5%) and high (8%) fat content, for each fat souce added, and distributed to 48 rabbits (12 x 4) with 35 days of age (recently weaned) housed in digestibility cages. The animals had access ad libitum to food and water during the 5 weeks of the experimental period, being slaughtered at 70 days of age. The zootechnical results were evaluated, without significant differences (P> 0.05) and feces were collected in the 4th week oh the trial, and analyzed to evaluate the apparent digestibility of the diets. The initial weights (1047g) were uniform and the final weights (2405g) were similar in all groups. It was verified that there is a very significant effect on the nature of fat (P <0.0001), on dry matter and organic matter digestibility. Insect oil regimes have a digestibility of DM and OM about 95% of the digestibility of the same fractions from flax oil regimes. Also, the digestibility of the EE (ethereal extract) and GE (gross energy) fractions were significantly lower (P <0.05) in the insect oil regimens. Regimens with higher fat contents increased the digestibility (P <0.0001) of ethereal extract, but decreased (P <0.003) the cellulose digestibility. Carcasses were analyzed, and there were no significant differences (P> 0.05) in digestive tract, liver, peri-renal and inter-scapular fat weights, only an effect on empty stomach weight (P = 0.006), higher in insect oil regimes, probably due to higher feed retention during the experimental period. Among the colorimetric results obtained, there appear to be no significant differences, except for a reddish in meat of the animals who ate insect oil regimes (P = 0.047). According to these results, insect fat can be used on rabbit diet, with only some slightly lower digestibility in dry matter and organic matter, but not affecting the growth or carcass yield.
N/A

Orientador: Marcos Franke Pinto
Banca: Manoel Garcia Neto
Banca: Massami Shimokomaki
Resumo: O objetivo deste trabalho foi avaliar a incorporação de ácidos graxos poliinsaturados (PUFA) na carne de frango com a utilização de ração enriquecida com óleo de soja e óleo de linhaça, associados a diferentes níveis de vitamina E. A inclusão de óleo de linhaça, substituindo o óleo de soja em diferentes proporções, e de vitamina E até o nível de 400 mg/kg de ração, não interferiu, de forma geral, nas características de desempenho e de composição de carcaça de frangos de corte da linhagem Cobb. O sexo das aves, por outro lado, influenciou significativamente essas características. Os machos apresentaram, em termos gerais, melhor desempenho produtivo que as fêmeas, com maior consumo de ração e ganho de peso e melhor conversão alimentar. As fêmeas apresentaram maior porcentagem de peito e menor porcentagem de coxa e sobrecoxa que os machos. Com relação às características da carne, o sexo e a fonte de ácidos graxos poliinsaturados e os níveis de vitamina E da ração não apresentaram influência no teor de lipídeos totais, na textura e na perda de peso no cozimento. A adição de linhaça na dieta também não modificou o padrão de ácidos graxos, nem o teor de colesterol da carne. Os machos apresentaram maior proporção de PUFA que as fêmeas nos dois cortes analisados. Com relação ao teor de colesterol total, as amostras de peito provenientes dos machos apresentaram médias mais elevadas em relação às das fêmeas. A inclusão de 200mg/kg de vitamina E na ração foram suficientes para impedir a rancidez oxidativa nas amostras de coxa e sobrecoxa com pele, estocadas a -25ºC por 45 dias.
Abstract: The aim of this work was to evaluate the incorporation of polyunsaturated fatty acids (PUFA) in broilers meat using soy and linseed oil enriched rations and different levels of vitamin E. The inclusion of different percentages of linseed oil instead of soy oil and vitamin E until 400 mg/kg in the diets did not interfere in overall performance or composition characteristics of Cobb broilers carcasses. On the other hand, broilers' sexes influenced these characteristics. Male broilers consumed more ration, had higher weight gains and better feed conversions than female broilers. Female broilers had higher breast percentages and lower leg percentages than male broilers. Sex, source of polyunsaturated fatty acids and vitamin E level did not influence total fat content of meat, texture and loose of weight after cooking. The inclusion of linseed oil in the diet did not cause any modification on meat fatty acids composition or total cholesterol content. Male broilers breast and leg samples had higher PUFA content than female broilers. Male broilers had higher cholesterol contents than female broilers in breast cuts. Vitamin E at 200 mg/kg was enough to prevent oxidative rancidity in leg samples frozen at -25ºC for 45 days.
Mestre

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo deste trabalho foi avaliar a incorporação de ácidos graxos poliinsaturados (PUFA) na carne de frango com a utilização de ração enriquecida com óleo de soja e óleo de linhaça, associados a diferentes níveis de vitamina E. A inclusão de óleo de linhaça, substituindo o óleo de soja em diferentes proporções, e de vitamina E até o nível de 400 mg/kg de ração, não interferiu, de forma geral, nas características de desempenho e de composição de carcaça de frangos de corte da linhagem Cobb. O sexo das aves, por outro lado, influenciou significativamente essas características. Os machos apresentaram, em termos gerais, melhor desempenho produtivo que as fêmeas, com maior consumo de ração e ganho de peso e melhor conversão alimentar. As fêmeas apresentaram maior porcentagem de peito e menor porcentagem de coxa e sobrecoxa que os machos. Com relação às características da carne, o sexo e a fonte de ácidos graxos poliinsaturados e os níveis de vitamina E da ração não apresentaram influência no teor de lipídeos totais, na textura e na perda de peso no cozimento. A adição de linhaça na dieta também não modificou o padrão de ácidos graxos, nem o teor de colesterol da carne. Os machos apresentaram maior proporção de PUFA que as fêmeas nos dois cortes analisados. Com relação ao teor de colesterol total, as amostras de peito provenientes dos machos apresentaram médias mais elevadas em relação às das fêmeas. A inclusão de 200mg/kg de vitamina E na ração foram suficientes para impedir a rancidez oxidativa nas amostras de coxa e sobrecoxa com pele, estocadas a -25ºC por 45 dias.
The aim of this work was to evaluate the incorporation of polyunsaturated fatty acids (PUFA) in broilers meat using soy and linseed oil enriched rations and different levels of vitamin E. The inclusion of different percentages of linseed oil instead of soy oil and vitamin E until 400 mg/kg in the diets did not interfere in overall performance or composition characteristics of Cobb broilers carcasses. On the other hand, broilers` sexes influenced these characteristics. Male broilers consumed more ration, had higher weight gains and better feed conversions than female broilers. Female broilers had higher breast percentages and lower leg percentages than male broilers. Sex, source of polyunsaturated fatty acids and vitamin E level did not influence total fat content of meat, texture and loose of weight after cooking. The inclusion of linseed oil in the diet did not cause any modification on meat fatty acids composition or total cholesterol content. Male broilers breast and leg samples had higher PUFA content than female broilers. Male broilers had higher cholesterol contents than female broilers in breast cuts. Vitamin E at 200 mg/kg was enough to prevent oxidative rancidity in leg samples frozen at -25ºC for 45 days.

O carcinoma hepatocelular (HCC) apresenta mau prognóstico o que torna importante sua quimioprevenção. Nesse sentido, a tributirina (TB), um inibidor de desacetilases de histonas (HDACi), mostrou-se um quimiopreventivo promissor da hepatocarcinogênese. Avaliaram-se aqui efeitos quimiopreventivos de lipídios estruturados (EST) obtidos por interesterificação enzimática a partir da TB com o óleo de linhaça (LIN). Ratos foram tratados com EST (grupo EST; 165 mg/100g peso corpóreo [p.c]), TB (grupo TB; 200 mg/100g p.c), LIN (grupo LIN; 133 mg/100g p.c), mistura de TB com LIN (grupo LIN; 165 mg/100g p.c) ou maltodextrina (MD) (grupo MD; controle isocalórico; 300 mg/100g p.c) diariamente durante 8 semanas consecutivas por gavagem. Duas semanas após início dos tratamentos, os animais foram submetidos ao modelo de hepatocarcinogênese do \"hepatócito resistente\" (RH). Os grupos EST e TB apresentaram atividade quimiopreventiva bloqueadora e supressora, respectivamente, da hepatocarcinogênese. TB induziu a apoptose, ao contrário dos EST. O tratamento com TB resultou na acetilação e trimetilação da H3K9 e H3K27, enquanto EST atuaram somente na trimetilação das mesmas. Quando analisada a expressão de genes envolvidos com modificações em histonas, EST e TB reduziram a expressão de Ezh2 e de Hdac4. Por outro lado, somente os EST aumentaram a expressão de Hdac6. Tal efeito por parte dos EST merece ser mais investigado, uma vez que esta desacetilase vem sendo sugerida como alvo potencial para o desenvolvimento de fármacos. Em conclusão, a atividade quimiopreventiva de EST e da TB envolve na hepatocarcinogênese experimental mecanismos epigenéticos que podem ou não ser distintos.
Hepatocellular carcinoma (HCC) has a poor prognosis, which makes its chemoprevention important. Tributyrin (TB), which is a histone deacetylase inhibitor (HDACi), is a promising chemopreventive agent of hepatocarcinogenesis. The chemopreventive effects of structured lipids (STLs) that were obtained by the enzymatic interesterification of TB with flaxseed oil (FSO) were evaluated in the present study. Rats were treated with STLs (STL group, 165 mg/100 g body weight (bw)), TB (TB group, 200 mg/100 g bw), FSO (FSO group, 133 mg/100 g bw), TB mixed with FSO (BLD group, 165 mg/100g bw) or maltodextrin (MD) (MD group; isocaloric control; 300 mg/100 g bw) daily for eight consecutive weeks by gavage. Two weeks after the initiation of treatment, the animals were subjected to the resistant hepatocyte hepatocarcinogenesis model (RH). The STL and TB groups developed blocker and suppressive chemopreventive activity against hepatocarcinogenesis, respectively. TB treatment induced apoptosis, unlike the STL treatment. Additionally, TB treatment resulted in the acetylation and trimethylation of H3K9 and H3K27, whereas the STLs acted only in the trimethylation of these histones. When analyzing the expression of genes involved in histone modifications, the STLs and TB reduced enhancer of zeste homolog 2 (Ezh2) and histone deacetylase 4 (Hdac4) gene expression. Conversely, only the STLs increased Hdac6 gene expression. This effect of the STLs warrants further investigation because this deacetylase has been suggested as a potential drug development target. In conclusion, the chemopreventive activities of the STLs and TB in experimental hepatocarcinogenesis involve epigenetic mechanisms that may be distinct.

A combinação de agentes quimiopreventivos com diferentes mecanismos de ação tem sido considerada uma estratégia promissora para a prevenção do câncer. Dentre os diversos compostos bioativos em alimentos, destacam-se a tributirina, um pró-fármaco do ácido butírico presente em laticínios e produzido pela fermentação de fibras dietéticas, e o óleo de linhaça, fonte de ácido alfa linolênico. Nesse contexto, foi avaliada a atividade quimiopreventiva de lipídios estruturados obtidos a partir da interesterificação enzimática de tributirina e óleo de linhaça durante a fase de promoção inicial da hepatocarcinogênese experimental. Ratos Wistar machos submetidos ao modelo do hepatócito resistente receberam diariamente, por via intragástrica (i.g), maltodextrina, óleo de linhaça, tributirina, a mistura não esterificada ou lipídios estruturados durante a fase de promoção inicial. O tratamento com lipídios estruturados demonstrou atividade quimiopreventiva comparável à da tributirina, mesmo resultando em menor concentração hepática de ácido butírico. Tanto a tributirina quanto os lipídios estruturados não inibiram a proliferação celular em lesões preneoplásicas, mas induziram a apoptose naquelas em remodelação. Os efeitos inibitórios da tributirina em fases iniciais da hepatocarcinogênese experimental estão relacionados ao aumento da acetilação de histonas e à modulação de processos de translocação nuclear da p53. No presente estudo, foi observado aumento substancial da razão nuclear/citoplasmática de p53 e importina-alfa em fígados de animais submetidos ao modelo e tratados com tributirina, mas não nos tratados com lipídios estruturados. Por outro lado, o tratamento com lipídios estruturados reduziu a expressão dos oncogenes Bcl2, Ccnd2, Pdgfa, Vegfa e aumentou a expressão dos genes supressores de tumor Cdh13, Fhit e Socs3. Assim, embora o potencial quimiopreventivo dos lipídios estruturados seja comparável ao da tributirina, os resultados sugerem que o novo composto não exibe atividade de HDACi, e que seus efeitos inibitórios na hepatocarcinogênese possam ser atribuídos à modulação da expressão de oncogenes e genes supressores de tumor.
Combination of chemopreventive agents with different mechanisms of action has been considered a promising strategy to cancer prevention. Among several bioactive food compounds, tributyrin, a butyric acid prodrug obtained from dairy products and dietetic fiber fermentation, and flax seed oil, a rich source of alpha linolenic acid have shown chemopreventive potential. Here, we evaluated the chemopreventive activity of structured lipids obtained by enzymatic interesterification of tributyrin and flax seed oil during the early promotion phase of experimental hepatocarcinogenesis. Male Wistar rats subjected to the resistant hepatocyte model were treated daily, i.g, with maltodextrin, flax seed oil, tributyrin, non-sterified blend, or structured lipids. Treatment structured lipids showed similar chemopreventive activity compared to tributyrin, even when structured lipids yielded lower concentrations of butyric in the liver. Tributyrin and structured lipids did not inhibit cell proliferation in preneoplastic lesions, but both of them induced apoptosis in remodeling preneoplastic lesions. In addition, histone acetylation and p21 restored expression tributyrin molecular mechanisms were related to modulation of p53 nuclear shuttling mechanisms. In the present study, it was observed a substantial increase in p53 nuclear/cytoplasmic ratio and importin-alpha in preneoplastic livers of tributyrin treated rats, but not in those treated with structured lipids. In contrast, treatment structured lipids downregulated expression of major oncogenes Bcl2, Ccnd2, Pdgfa, and Vegfa; and upregulated expression of critical tumor suppressor genes, Cdh13, Socs3 and Fhit. Hence, although structured lipids and tributyrin show similar chemopreventive potential, the results suggest that the new compound does not exhibit HDACi activity, and that its inhibitory effects may be attributed to the modulation of oncogenes and tumor suppressor genes expression.

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The heat transfer characteristics of pure R-114 and R-114/oil mixtures during nucleate pool boiling from a small bundle of finned and High Flux tubes were measured. The bundles had 5 instrumented and 10 additional heated tubes of 15.8 mm outside diameter which were arranged in an equilateral triangular pitch of 19.1 mm giving a pitch-to-diameter ratio of 1.2. Pure refrigerant with York-C lubrication oil mass con-centrations of 1, 2, 3, 6 and 10% was used. All experiments were performed at 2.2C corresponding to a pressure slightly below atmospheric. Data sets were taken using decreasing heat flux only in order to avoid the boiling hysterisis phenomenon. An enhancement in heat-transfer performance of the finned tube bundle due to oil applications was observed. The enhancement increased with up to 3% oil concentration over all heat flux ranges. Further oil additions showed better performances than pure R-114 at high heat flux levels but poorer performance was obtained at lower heat fluxes. High flux tube experiments indicated that the heat transfer performance of the bundle was approximately 2.5 times better than the finned tube bundle performance for pure R-114. No positive performance enhancement was observed from the High Flux tube bundle due to oil addition. The performance immediately degraded with 1% oil and stayed almost constant with 2% and 3% oil additions. A decrease of performance became significant at high heat flux levels with oil concentrations of 6% and 10%. The performance of these two tube bundles was compared to smooth tube operation.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 1990.
Thesis Advisor(s): Marto, Paul J. ; Memory, Steve. "December 1990." Description based on title screen as viewed on March 30, 2010. DTIC Identifier(s): Pool Boiling. Author(s) subject terms: Heat Transfer, Pool Boiling. Includes bibliographical references (p. 102-104). Also available in print.

Flax and hemp seed oils are rich sources of alpha-linolenic acid (ALA; 18:3n-3), which can be converted to eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in humans. We investigated the effects of these oils on erythrocyte concentrations of EPA, DHA, other fatty acids, and plasma lipids in healthy vegetarians. Twenty-two subjects consumed either one tablespoon of flax (7.1 g ALA) or hemp seed oil (2.2 g ALA) daily for twenty-eight days. Diet records were collected at baseline and during supplementation. Blood samples were collected at baseline and post-supplementation. No significant increases in plasma EPA, DHA or dihomo-gamma-linolenic acid (DGLA; 18:3n-6) were observed in either group. Significant increases in plasma high-density lipoprotein cholesterol (HDL) concentrations were observed in both groups. Flax and hemp seed oils were not effective at increasing erythrocyte EPA, DHA or DGLA concentrations but were effective at increasing HDL concentrations.
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The performance of a submerged membrane bioreactor for the duty of gas field produced water treatment was appraised. The system was operated under steady state conditions at a range of mixed liquor suspended solids (MLSS) concentrations and treatment and membrane performance examined. Organics removal (COD and TOC) display removal rates between 90 and 97%. Removal of specific target compounds Benzene, Toulene, Ethylbenzene and Xylene were removed to above 99% in liquid phase with loss to atmosphere between 0.3 and 1%. Comparison of fouling rates at a number of imposed fluxes has been made between long term filtration trials and short term tests using the flux step method. Produced water fed biomass displays a greater fouling propensity than municipal wastewater fed biomass from previous studies. Results indicate an exponential relationship between fouling rate and flux for both long and short term trials, although the value was an order of magnitude lower during long term tests. Moreover, operation during long term trials is characterised by a period of pseudo stable operation followed by a catastrophic rise in TMP at a given critical filtration time (tfi, ) during trials at 6 g. L"1. This time of stable operation, tfit, is characterised by a linear relationship between fouling rate and flux. Results have been compared with the literature. Data for membrane fouling prior to the end of t fit yielded a poor fit with a recently proposed model. Trends recorded at t> trlt revealed the fouling rate to follow no definable trend with flux. The system showed resilience to free oil shocking up to an oil concentration of 200ppmv. Following an increase in oil concentration to 500 ppmv, rapid and exponential fouling ensued.

The current standard electrical downhole machine is the induction machine which is relatively inefficient. Permanent magnet (PM) machines, having higher efficiencies, higher torque densities and smaller volumes, have widely employed in industrial applications to replace conventional machines, but few have been developed for downhole applications due to the high ambient temperatures in deep wells and the low temperature stability of PM materials over time. Today, with the development of variable speed drives and the applications of high temperature magnet materials, it is increasingly interesting for oil and gas industries to develop PM machines for downhole applications. Recently, some PM machines applications have been presented for downhole applications, which are normally addressed on certain specific downhole case. In this thesis the focus has been put on the performance investigation of different PM machines for general downhole cases, in which the machine outer diameter is limited to be small by well size, while the machine axial length may be relatively long. The machine reliability is the most critical requirement while high torque density and high efficiency are also desirable. The purpose is to understand how the special constraints in downhole condition affect the performances of different machines.  First of all, three basic machine concepts, which are the radial, axial and transverse flux machines, are studied in details by analytical method. Their torque density, efficiency, power factor and power capability are investigated with respect to the machine axial length and pole number. The presented critical performance comparisons of the machines provide an indication of machines best suitable with respect to performance and size for downhole applications. Conventional radial flux permanent magnet (RFPM) machines with the PMs on the rotor can provide high torque density and high efficiency. This type of machine has been suggested for several different downhole applications. Flux-switching PM (FSPM) machines, which have the PMs located on the stator and are therefore more reliable, can theoretically also exhibit high torque density and relatively high efficiency. This thesis has put an emphasis on studying this type of machine. Two FSPM machines have been investigated in detail and compared by analytical method, FEM simulation and prototype measuremens. Their operating principle and important design parameters are also presented. A lumped parameter magnetic circuit model for designing a high-torque FSPM machine is newly introduced and the designed machine is verified by FEM simulations. A prototype machine with an outer diameter of 100 mm and an axial length of 200 mm is built in the laboratory and tested at room temperature. Based on that, the machine performance at an ambient temperature of 150°C is also predicted. The results show that the FSPM machine can provide a high torque density with slight compromise of efficiency and power factor. Choosing a proper machine type is significantly dependent on the application specifications. The presented results in this thesis can be used as a reference for selecting the best machine type for a specific downhole case.

This thesis presents research on upward pointing oil jets that provide cooling of downward facing heated surfaces. The specific purpose of this research is to improve understanding of the oil jet cooling of internal combustion engine pistons. In this research, the cooling of heated blocks with flat and concave surfaces was investigated. Temperature measurements were obtained using an array of thermocouples embedded inside the heated blocks. A flash illumination and high resolution CCD camera system was used to observe the liquid jet impingement. Observations identified a 'bell-sheet' flow pattern, jet interference, jet splatter and jet breakup which provided insights into the liquid jet impingement processes normally encountered on downwardfacing surfaces. Bespoke contracting-type nozzles were used to produce the jet flow structure. The data from these nozzles were used to generate new empirical correlations for oil jet cooling of downward-facing flat surfaces and for predicting the size 6f impingement. The results obtained from these tests were also used for comparison with cooling jets from production automotive piston cooling nozzles. The research has demonstrated that the effectiveness of oil jet cooling can be affected by preheating the oil and varying the injector size to alter the targeted cooling efficiency, and liquid loss due to jet breakup and splatter. Local heat transfer coefficients were observed to increase when the jet Reynolds number increased. Piston undercrown cooling was studied using a range of oil jet configurations. The cooling rates improved with optimised targeted jets. The results also indicated that the undercrown geometry designs such as crosshatched surfaces, undercrown-skirt and gudgeon-pin boss, were significant for enhancing the local rate of forced convective heat transfer. New empirical correlations were developed from the experimental results that enabled prediction of the heat transfer coefficient and jet impingement size for high Prandtl number liquid jets impinging onto downward-facing surfaces. The heat transfer correlations were developed for normal (θ = 90°) and inclined (θ = 75°, 60° and 45°) jet impingements.

Renewable energy sources are vital to reduce dependence on fossil fuels that are harmful for the environment and release greenhouse gases causing global warming. Wind energy is a natural source of energy that is abundant in the environment. While wind turbines are most popular, convenient, and used to harvest energy at large scales, there have been recent studies focusing on harvesting energy from the wind for microdevices. Such micro wind energy harvesters can decrease dependence on batteries. In this study, a novel, framed flag micro wind harvester was designed and tested, and its behavior at three different wind speeds was experimentally examined in a wind tunnel. The main purpose of this study is to determine the geometric and wind speed conditions under which regular flapping occurs in the flag material. A high-speed camera was used to visualize the motion of the harvester at different wind speeds and at various parametric ratios of the flag material length to the frame length. The movies taken by the camera are analyzed using Image J software to find the flapping frequency, flapping angle, and the amplitude. Nondimensional parameters such as the Re number and St number also are calculated. This study finds that parametric ratios of 1.1 and 1.2 with the medium wind speed condition of 5 m/s are optimal flapping conditions. These optimal conditions would conveniently allow the use of piezoelectric material as the flag material in order to harvest energy. Further, an advantage of this novel design over previous designs is that the wind harvester naturally aligns with the wind direction and is thus omnidirectional.

The main aim of this work id to provide integral methods to predict and characterize the properties of composite structures based on hybrid polymers and reinforcements, that could lead to useful results from an industrial point of view. This is addressed, if possible, by theoretical predictions of the effective properties by using the available experimental data. The first part is focused on the scientific achievements of the author that allowed a quantitative characterization of the main effective properties of several composite architectures from hybrid polymers and reinforcements, based on bio matrices, tailor-made matrices and different theoretical and simulation methods using computer software to allow good comparison. The second part defines the future research lines to continue this initial investigation. The main objectives are clearly defined to give the reader a sound background with the appropriate concepts that are specifically discussed in the following chapters. As a main objective, this research work makes a first attempt to provide a systematic analysis and prediction of composite hybrid structures.
El objetivo general del trabajo es proporcionar medios integrales para predecir y caracterizar las propiedades de las estructuras de compuestos basados en polímeros y refuerzos híbridos, principales que pueden producir resultados de utilidad práctica simultáneamente. Esto se logra comparando, siempre que sea posible, las predicciones teóricas de las propiedades efectivas con los datos experimentales disponibles. Una primera parte se ocupa de los logros científicos del autor que permitieron caracterizar cuantitativamente las principales propiedades efectivas de las arquitecturas de compuestos basados en polímeros y refuerzos híbridos, basados en matrices bio, auto-desarrollados y diferentes métodos teóricos y de simulación por ordenador utilizados para la comparación. La segunda parte identifica las orientaciones futuras para la evolución y desarrollo de la ciencia y la investigación. Los objetivos generales fueron subrayados y concisos para dar al lector una visión previa de los conceptos que serán discutidos específicamente en los siguientes capítulos. Indirectamente, apuntan hacia uno de los objetivos principales de este trabajo, a saber, proporcionar una dirección para el análisis sistemático de materiales compuestos a base de refuerzos híbridos.
L'objectiu general d'aquest treball es proporcionar els mitjos integrals per tal de predir i caracteritzar les propietats d'estructures de compòsits basats en polímers i reforçaments híbrids, que poden produir resultats amb utilitat pràctica simultàniament. Aquest objectiu s'aconsegueix comparant, sempre que és possible, les prediccions teòriques de les propietats efectives amb les dades experimentals disponibles. Una primera part es centra en els temes científics en què ha treballat l'autor que han permès caracteritzar quantitativament les principals propietats efectives de les arquitectures de compòsits basades en polímers i reforçaments híbrids, derivats de matrius bio, auto-desenvolupats i diferents mètodes teòrics i de simulació informàtica per a una correcta comparació. La segona part identifica les orientacions futures per tal d'establir l'evolució i desenvolupament de la ciència i investigació lligada a la temàtica de la tesi. Els objectius generals han sigut clarament definits per tal de donar-li al lector una visió prèvia i sòlida dels conceptes que es discuteixen en capítols venidors. Indirectament, apunten cap a un dels objectius principals d'aquest treball, a saber, proporcionar una direcció per a l'anàlisi sistemàtica de materials compòsits a base de polímers i reforçaments híbrids.
Motoc, D. (2017). Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90399
TESIS

La structure du flux optique est importante pour le controle des reactions optomotrices. Deux exemples de reactions optomotrices ont ete etudies: les reactions posturales et le reflexe optocinetique (roc). Nous avons pu montrer que ces reflexes sont controles par des voies visuelles dont le domaine de sensibilite est ajuste pour detecter les basses frequences spatiales et les frequences temporelles intermediaires. Le systeme postural et le roc traitent les informations de profondeur afin d'assurer un controle de l'orientation du corps ou de l'axe du regard dans l'espace. Concernant les reactions posturales, elles sont controlees a plusieurs niveaux des membres inferieurs et du tronc. L'analyse electromyographique infirme donc le modele du pendule inverse. Enfin, concernant le roc, il n'est pas completement inhibe durant la poursuite volontaire d'un objet se deplacant dans un environnement visuel. Cette intrusion optocinetique affecte la perception de la vitesse de la cible et le controle de la poursuite manuelle de cette cible

L'objectif principal de cette thèse est d'étudier la dynamique des flux hydrosédimentaires dans le bas cours de l'Orénoque à partir de la mise en œuvre de diverses techniques qui combinent directement la mesure des données in situ et la modélisation par séries chronologiques d'images satellites. Cette thèse aborde pour la première fois trois méthodologies complémentaires pour analyser les flux hydrosédimentaires dans les grands fleuves : (i) un algorithme d'inversion robuste pour l'estimation de MES à l'aide de données Landsat-8(OLI)permet de suivre de façon systématique et fiable les variations spatio-temporelles des flux hydro-sédimentaires de surface, (ii) de même, il a été montré qu'il existe une forte relation entre le coefficient de rétrodiffusion du radar (images Sentinel-1) et les segments fluviaux d'écoulement turbulent. Cette nouvelle utilisation du radar en complément des approches classiques en géomorphologie et hydro-sédimentologie permet d'identifier des sections du fleuve où les MES sont homogénéisées, ce qui est fondamental pour le calcul des flux hydro-sédimentaires en suspension, enfin, (iii) une troisième méthodologie a été mise en œuvre pour mesurer durant le cycle hydrologique, les modifications géomorphologiques d'une île semi-submergée au centre du chenal principal. Grace à des séries topo-bathymétriques fines, associées à une modélisation 3D, l'on peut dorénavant quantifier le charriage de fond. Ces trois approches combinées permettent une évaluation plus précise du bilan hydro-sédimentaire en tenant compte des matières en suspension comme du charriage de fond. Ces études pourront servir aux gestionnaires du fleuve, confrontés à de complexes, lourdes et couteuses opérations de dragage périodiques pour maintenir sa navigabilité, ce qui est d'extrême importance pour les projets de développement socio-économiques de la frange pétrolière du bas cours de l'Orénoque
The main objective of this thesis is to study the dynamics of hydro-sedimentary flows in the lower Orinoco from the implementation of various techniques that directly combine the measurement of in situ data and the modelling of time series of satellite images. This thesis addresses for the first time three complementary methodologies for the analysis of hydro-sedimentary flows in large rivers: i) a robust inversion algorithm for estimating suspended sediment concentration (SSC) using Landsat-8 (OLI) satellite data allows a systematic and reliable monitoring of spatial and temporal variations of surface hydro-sedimentary flows, (ii) it was shown that there is a strong relationship between the radar backscatter coefficient (Sentinel-1 images) and the turbulent flow segments in the river. This new use of radar, in addition to traditional geomorphological and hydro- sedimentological approaches, allows the identification of river sections in which suspended sediments are homogenized, which is fundamental for the calculation of suspended hydro-sedimentary flows, and finally (iii) a third methodology has been implemented to measure during the hydrological regime the geomorphological modifications of a semi-submerged island in the center of the mainstream. Thanks to a high spatial resolution topo-bathymetric series, combined with 3D modeling, it is now possible to quantify and to gain better understanding of river bed transport. These three combined approaches allow a more accurate evaluation of the hydro-sedimentary equilibrium taking into account suspended solids as well as bedload. These studies can be used by those responsible for river management, who face complex, heavy and costly periodic dredging operations to maintain their navigability, which is of extreme importance for socio-economic development projects in the Orinoco oil belt in the lower Orinoco

Les lasers solides émettant dans l’UV et le vert suscitent de gros efforts de recherche. Ainsi 3 nouveaux cristaux non linéaires ont été développés et caractérisés pour réaliser la conversion de fréquence dans le domaine UV: 2 matériaux congruents BaNaB9O15 et BaCaBO3F, et un matériau non congruent Ca5(BO3)3F. Leurs principales propriétés optiques et leurs champs d’application ont été déterminés. Pour Ca5(BO3)3F, des premiers tests de doublage à 1064 nm avec estimation des coefficients effectifs non linéaires ont été effectués. L'autodoublage de l'Yb dans GdCOB et YCOB a aussi été étudié pour générer directement une émission laser verte. Des cristaux ont été taillés pour différentes configurations (propagation, longueur d'onde). En utilisant ces cristaux taillés, les caractéristiques spectroscopiques de l’Yb ont été mesurées. De très bonnes performances laser d’autodoublage dans le vert ont été obtenues.

L'imagerie par résonance magnétique fonctionnelle (IRMf) permet d'examiner l'organisation fonctionnelle du cerveau humain de manière non-invasive et chez les sujets sains. L'implémentation de cette technique chez des primates non-humains représente un progrès important dans les neurosciences des systèmes. D'une part, l'IRMf singe permet la réduction et le raffinement des protocoles invasifs impliquant des primates non humains, en révélant les régions d'intérêts dans lesquelles les approches focales invasives, électrophysiologiques ou anatomiques, devraient être menées. D'un autre côté, les connaissances acquises avec ces approches invasives peuvent être transposées plus aisément à l'homme, une fois que les homologies et différences interspécifiques ont été identifiées au travers de protocoles d'IRMf menées en parallèle chez les primates humains et non- humains. La 1ère partie de cette thèse présente les approches conventionnelles d'étude des fonctions cérébrales. Nous montrons que des études invasives chez l'animal demeurent nécessaires pour comprendre les mécanismes neuronaux qui sous-tendent nos fonctions cognitives, malgré le progrès des techniques d'investigation chez l'homme. Suit une revue sur l'évolution des techniques d'IRMf singe et certaines de ses réalisations majeures comme pont dressé entre les études non-invasives menées chez l'homme et les études invasives réalisées chez l'animal, notamment en ce qui concerne notre compréhension des mécanismes neuronaux permettant la saisie manuelle d'objets sous contrôle visuel. Purement méthodologique, la fin de cette 1ère partie décrit l'animalerie et la plate-forme d'IRM à Toulouse et expose les jalons de l'implémentation de l'IRMf chez le singe macaque vigile. La 2ème partie de la thèse présente les 4 études que nous avons menées en IRMf singe. La 1ère étude modélise la réponse hémodynamique chez le singe, un outil indispensable à l'analyses de données d'IRMf, acquises dans les études suivantes. La 2ème étude traite de l'organisation visuotopique du cortex visuel dorsal des primates, et y décrit un nouvel assemblage d'aires visuotopiques chez 2 animaux, grâce à l'usage de nouvelles techniques de stimulation visuelle et d'analyse de champ récepteurs. Ces résultats apportent un point de vue neuf sur l'organisation fonctionnelle de la voie visuelle dorsale et ouvrent de nombreuses perspectives pour les comparaisons entre espèces. La 3ème étude cartographie le réseau d'aires corticales impliqué dans le traitement du flux optique chez les primates non humains et le compare à celui décrit récemment chez l'homme. Grâce à la réplication d'une étude réalisée chez l'homme, nous avons confirmé chez 3 macaques l'implication de zones précédemment identifiées par des enregistrements électrophysiologiques. Nos résultats révèlent de nouvelles zones corticales impliquées dans le traitement du flux optique, dessinant l'image d'un réseau cortical partageant de nombreuses similitudes, mais ayant également des différences frappantes, avec celui documenté dans le cerveau humain. En résumé, l'ambition de cette thèse est double : (1) fournir des recommandations pour la mise en place de techniques IRMf chez le singe, tirées de notre propre expérience et (2) exposer les résultats d'un ensemble d'études que nous avons menées avec cette approche, traitant de l'organisation visuotopique du cortex visuel dorsal et de son implication dans le traitement du mouvement visuel. En plus d'apporter une perspective nouvelle sur l'organisation fonctionnelle du cortex visuel chez les primates non humains, ces études illustrent la contribution de l'IRMf singe comme pont entre études électrophysiologiques chez les primates non humains et études d'imagerie fonctionnelle chez l'homme
Functional magnetic resonance imaging (fMRI) allows addressing the functional organization of the human brain with minimal invasiveness and in healthy individuals. The implementation of that technique in non-human primates represents an important achievement in systems neuroscience. On the one hand, monkey fMRI contributes to the reduction and refinement of invasive approaches in non-human primates, by revealing the regions of interest in which focal electrophysiological and/or anatomical investigations should be carried out. On the other hand, the knowledge acquired with such invasive approaches can be more safely transposed to humans, once inter-species homologies and differences have been identified through the use of similar fMRI protocols in human and non-human primates. The first part of this thesis reviews the most common approaches that have been used to study brain functions, either in humans or in non-human primates. It is shown that despite progresses in the human approaches, invasive studies in monkeys remain necessary for understanding the neuronal mechanisms underlying cognitive functions. Then follows a description of the evolution of the monkey fMRI techniques and some of its achievements in bridging the gap between non-invasive human studies and invasive animal studies, notably for deciphering the neural mechanisms supporting visually-guided grasping. The end of this first part is purely methodological. It undertakes the description of the monkey facilities and the MR platform in Toulouse, and details the necessary milestones for conducting fMRI research in macaque monkeys. The second part of the thesis presents the 4 studies we have conducted with monkey fMRI. The first study is a preparatory experiment for characterizing the monkey hemodynamic response function, which is a prerequisite for proper analysis of subsequent monkey fMRI data. The second study addresses the visuotopic organization of the primate dorsal visual cortex with a novel technique of wide-field (80°) phase-encoded visual stimulation, coupled with a state of the art surface-based analysis of population receptive fields. The results obtained in 2 animals uncover a new cluster of visuotopic areas in the posterior parietal cortex of the macaque monkey, bringing a fresh view to the functional organization of this piece of cortex and opening a promising avenue for inter-species comparisons. The third study unveils the cortical network involved in optic flow processing in non-human primates and it compares this network to that recently described in humans. To that end, we replicated in macaque monkeys an experiment previously conducted in human subjects with optic flow stimuli that are either consistent or inconsistent with egomotion. Besides confirming the involvement of areas previously identified through electrophysiological recordings, our results reveal new cortical areas involved in the processing of optic flow, drawing the picture of a network sharing many similarities, but also striking differences, with that documented in the human brain. In summary, the ambition of this thesis is two-fold: (1) providing guidelines for setting-up monkey fMRI techniques, drawn from our own experience and (2) exposing a set of studies we have conducted with this approach, dealing with the visuotopic organization of the dorsal visual cortex and its involvement in the processing of visual motion. Besides bringing a fresh view to the functional organization of the dorsal visual pathway in non-human primates, these studies illustrate how monkey fMRI bridges the gap between electrophysiological studies in non-human primates and functional imaging studies in humans

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Novel cementing materials formulations containing flexible polymeric admixtures have been studied aiming at improving the mechanical behavior of oil well cement slurries submitted to steam injection. However, research activities in this sector are still under development. The steam injected directly into the well causes casing dilation, which after a reduction in temperature, tends to return to its original dimensions, resulting in crack formation and hydraulic isolation loss of the well, which will result in shortening of well life. In this scenario, the objective of the present study was to evaluate the mechanical behavior of Portland-based slurries containing SBR latex, applied in oil well cementing of wells submitted to steam injection. Were formulated slurries with densities of 1.797 g/cm3 (15.0 lb/Gal) and 1.869 g/cm3 (15.6 lb/Gal), containing admixtures with a latex concentration of 0; 66.88; 133.76; 200.64 and 267.52 L/m3 (0, 0.5, 1.0, 1.5 and 2.0 gpc). Tests including rheology, fluid loss control, thickening time, API compressive strength and splitting tensile strength, beyond steam injection simulation. Microstrutural characteristics of the slurries were also performed (XRD, TG, FTIR and SEM). The results showed that increasing the polymer concentration increased in the rheological properties and fluid loss, and a decrease in the elasticity modulus of the cement slurries. The results obtained showed that the slurries can be applied in cementing operations of oil wells submitted to steam injection.
Novas formula??es de pastas de cimento, aditivadas com materiais polim?ricos com caracter?sticas flex?veis, t?m sido estudadas para aplica??o em po?os sujeitos a inje??o de vapor. Entretanto, pesquisas neste setor ainda s?o atividades em desenvolvimento. O vapor injetado diretamente no po?o provoca a dilata??o do revestimento, o que ap?s redu??o na temperatura, tende a voltar as suas dimens?es iniciais, provocando forma??o de trincas e conseq?ente perda do isolamento hidr?ulico do po?o, que resultar? no encurtamento do tempo de sua vida ?til. Dentro deste contexto, este trabalho tem como objetivo estudar o comportamento mec?nico de sistemas de pastas de cimento Portland, aditivadas com l?tex SBR, para cimenta??o de po?os de petr?leo sujeitos a inje??o de vapor. Foram formuladas pastas com densidades de 1,797 g/cm3 (15,0 lb/Gal) e 1,869 g/cm3 (15,6 lb/Gal), aditivadas com concentra??o de 0; 66,88; 133,76; 200,64 e 267,52 L/m3 (0, 0,5, 1,0, 1,5 e 2,0 gpc) de l?tex. Foram realizados ensaios de reologia, controle de filtrado, tempo de espessamento, resist?ncia ? compress?o API e tra??o por compress?o diametral, al?m de simula??es de inje??o de vapor. Tamb?m foram realizadas caracteriza??es microestruturais das pastas de cimento (DRX, TG, FTIR e MEV). Os resultados mostraram que com o aumento da concentra??o do pol?mero ocorreram mudan?as nas propriedades reol?gicas e no volume de filtrado, al?m de uma diminui??o do m?dulo de elasticidade das pastas de cimento. A partir dos resultados obtidos verificou-se que as pastas podem ser aplicadas em opera??es de cimenta??o de po?os de petr?leo sujeitos a inje??o de vapor.

Les neuropathies optiques comme le glaucome sont souvent des maladies tardives, évolutives et incurables. Malgré les progrès récents de la recherche clinique, de nombreuses questions relatives à l’étiologie de ces troubles et à leur physiopathologie restent ouvertes. De plus, les données sur les tissus postérieurs oculaires sont difficiles à estimer de façon non invasive et leur interprétation clinique demeure difficile en raison de l’interaction entre de multiples facteurs qui ne peuvent pas être facilement isolés. L’utilisation récente de modèles mathématiques pour des problèmes biomédicaux a permis de révéler des mécanismes complexes de la physiologie humaine. Dans ce contexte très enthousiasmant, notre contribution est consacrée à la conception d’un modèle mathématique et computationnel couplant l’hémodynamique et la biomécanique de l’oeil humain. Dans le cadre de cette thèse, nous avons mis au point un modèle spécifique au patient appelé simulateur virtuel de mathématiques oculaires (OMVS), capable de démêler les facteurs multi-échelles et multi-physiques dans un environnement accessible en utilisant des modèles mathématiques et des méthodes numériques avancés et innovants. De plus, le cadre proposé peut servir comme méthode complémentaire pour l’analyse et la visualisation des données pour la recherche clinique et expérimentale, et comme outil de formation pour la recherche pédagogique
Optic neuropathies such as glaucoma are often late-onset, progressive and incurable diseases. Despite the recent progress in clinical research, there are still numerous open questions regarding the etiology of these disorders and their pathophysiology. Furthermore, data on ocular posterior tissues are difficult to estimate noninvasively and their clinical interpretation remains challenging due to the interaction among multiple factors that are not easily isolated. The recent use of mathematical models applied to biomedical problems has helped unveiling complex mechanisms of the human physiology. In this very compelling context, our contribution is devoted to designing a mathematical and computational model coupling tissue perfusion and biomechanics within the human eye. In this thesis we have developed a patient-specific Ocular Mathematical Virtual Simulator (OMVS), which is able to disentangle multiscale and multiphysics factors in a accessible environment by employing advanced and innovative mathematical models and numerical methods. Moreover, the proposed framework may serve as a complementary method for data analysis and visualization for clinical and experimental research, and a training application for educational purposes

Pour répondre à la demande mondiale croissante en huile et en protéines, le tournesol apparaît comme une culture très compétitive grâce à la diversification de ses débouchés et son attractivité environnementale et nutritionnelle. Pourtant, les teneurs en huile et protéines sont soumises à des effets génotypiques et environnementaux qui les rendent fluctuantes et difficilement prédictibles. Nous argumentons qu’une meilleure connaissance des effets les plus importants et leurs interactions devrait permettre de mieux prédire ces teneurs. Deux approches de modélisation ont été développées. Dans la première, trois modèles statistiques ont été construits puis comparés à un modèle simple existant. L’approche dynamique est basée sur l’analyse des relations source-puits au champ et en serre (2011 et 2012) pendant le remplissage. Les performances et domaines de validité des deux types de modélisation sont comparés
Considering the growing global demand for oil and protein, sunflower appears as a highly competitive crop, thanks to the diversification of its markets and environmental attractiveness and health. Yet the protein and oil contents are submitted to genotypic and environmental effects that make them fluctuating and hardly predictable. We argue that a better knowledge of most important effects and their interactions should permit to improve prediction. Two modeling approaches are proposed: statistical one, where we compared three types of statistical models with a simple existing one. The dynamic approach is based on source-sink relationships analysis (field and greenhouse experiments in 2011 and 2012) during grain filling. Performances of both modeling types and their validity domain are compared

La connaissance de la dynamique artérielle ophtalmique est pauvre, principalement issue des études Doppler et rien n'existe sur la composante veineuse. La physiopathologie du Glaucome est encore débattue et perfectible. Les études pointent notamment la vascularisation comme origine potentielle de cette affection, sans parvenir à proposer un modèle physiopathologique qui rassemble les différentes hypothèses. L'IRM en contraste de phase (IRM-PC) est une séquence non invasive, quantitative pour la mesure de la dynamique vasculaire. Principalement utilisée sur les artères de larges diamètres l'IRM PC, n'est à ce jour, pas utilisée sur l'artère et la veine ophtalmique. Le but de ce travail est de quantifier par IRM PC la dynamique vasculaire de l'artère ophtalmique (AO) et de la veine ophtalmique supérieure (VOS) sur une population saine. Dans une seconde étape d'appliquer l'IRM PC chez des patients atteints de glaucome. 21 volontaires sans affections ophtalmiques et 11 patients diagnostiqués comme porteurs d'un Glaucome ont été inclus. Les sujets ont bénéficié dans les mêmes conditions d'un examen sur une IRM 3 Tesla disposant d'une séquence IRM PC. Les AO et VOS gauches et droites ont été identifiées sur des séquences morphologiques pour positionner perpendiculairement l'IRM PC. Les IRM PC ont été analysées par un logiciel dédié pour calculer le débit a chaque phase du cycle cardiaque et construire la courbe d'évolution du débit au cours du cycle cardiaque de chaque vaisseau. Et en calculer : le débit moyen, maximal et minimal et les vitesses. Les résultats obtenus comme référence physiologique, montrent la faisabilité de cette technique. Il est mis en évidence l'existence d'une pulsatilité veineuse non négligeable au cours du cycle cardiaque. La dynamique vasculaire des patients glaucome (pulsatilité) était diminuée. Une corrélation largement significative entre le débit et la vitesse maximale a été mise en évidence dans la veine ophtalmique supérieure des témoins, qui n'était pas retrouvée chez les patients. En conclusion, notre travail a confirmé la possibilité d'étudier par IRM-PC la dynamique du débit sanguin dans l'AO et la VOS. Dans le glaucome, nous avons montré l'existence d'une modification significative de la dynamique vasculaire de la VOS pouvant résulter d'une altération de l'écoulement du réseau capillaire et/ou de la pression d'aval
The dynamics of the vascular arterial and venous supply of the eye remains poorly understood, coming mainly from studies in Doppler color imaging with very little quantitative data about venous component. The physiopathology of glaucoma is still under debate, with many ongoing investigations and hypotheses. Among them, vascular changes have been suggested to be a possible cause for the disease, but no pathophysiology model could be proposed that connect the different current hypotheses. Phase contrast magnetic resonance imaging (PC MRI) is a non-invasive MRI sequence for quantitative measurement of the vascular dynamics of a system. So far mainly used to investigate large caliber arteries, PC MRI has not yet been used to measure flows of the ophthalmic artery and vein. The objective of this work was to quantify by PC MRI the blood flow and vascular dynamics of the ophthalmic artery (OA) and the superior ophthalmic vein (SOV) in a population of healthy subjects in a first part, and in glaucoma patients in a second part. In total, 21 volunteers without ocular disease and 11 patients diagnosed with glaucoma were included. They all underwent 3 Tesla MRI examination with PC MRI sequence, in the same settings. The right and left OA and SOV were identified using anatomic sequences, to place a PC MRI acquisition plane perpendicular to their course. PC MRI series were analyzed using a dedicated software, calculating the flow for each phase of the cardiac cycle and displaying the curve of flow during cardiac cycle for each vessel. From this data the mean, maximal and minimal blood flow for each vessel were calculated. The results obtained in healthy subjects showed the feasibility and reliability of the technique. They were considered as normal reference and were later used as control. Notably, a significant pulsatility of the venous flow during the cardiac cycle was demonstrated. In glaucoma patients, this venous pulsatility was significantly lower. Also in patients our results showed a loss of the correlation between the mean flow and the maximal velocity in the OA. The flow waveform and the relationships between flow, velocity and section of the SOV suggested an impairment of the venous hemodynamics in glaucoma, which could result from capillary changes and/or from downstream pressure changes

Cette étude porte sur la production des bio-huiles à partir de la pyrolyse de bois de hêtre et celui du pin représentant respectivement les bois durs et les bois tendres. Afin de répondre à la problématique liée à la séparation des composés chimique de valeur ajoutée de la bio-huile,une étude a été effectuée sur la faisabilité d’une pré-séparation des constituants chimiques de la bio-huile à l’aide d’une pyrolyse étagée en température dans un réacteur en lit fixe de sorte à cibler la thermo-décomposition sélective des macro-composants de la biomasse (hémicellulose, cellulose et lignine). L’identification du couple macro-composant – marqueur de la décomposition est réalisée à partir du bilan en macro-composant dans le solide résiduel et l’identification par GC/MS des constituants contenus dans la bio-huile produite. Les résultats de cette partie ont montré la possibilité de la pré-séparation des fractions de dérivés de furane et des produits phénoliques, cependant le gain en sélectivité se fait au détriment du rendement total de la bio-huile. La deuxième partie de ce travail concerne l’étude de la production de la bio-huile dans les conditions de pyrolyse rapide dans un réacteur gaz/solide.Afin d’établir une relation entre les conditions opératoires de pyrolyse et la composition des bio-huiles, un outil permettant la comparaison pertinente des testes expérimentaux a été élaboré. Les expériences ont montré que le rendement de et la composition de l’huile de pyrolyse dépend essentiellement de : la nature du bois, la vitesse de chauffe et le temps de séjours effectif des particules de bois dans le réacteur
This research study is concerned in the production of bio-oils from the pyrolysis of beech and pines wood representing the hard and soft wood, respectively. In order to resolve the problems related to the separation of high added value molecules from the bio-oil, a study was held out on the feasibility of the pre-separation of the chemical components of bio-oil using of a staged pyrolysis temperature in a fixed bed reactor in order to target selective thermal decomposition of macro-components of biomass (hemicellulose, cellulose and lignin). The identification of macro-component couples - marker of decomposition is made from the balance macro-component in the residual solid and identification by GC / MS of the chemical components contained in the produced bio-oil. The results of this part have shown the possibility of the pre-separation of furans and phenolic derivatives, despite of the gain in selectivity at the expense of overall yield of bio-oil. The second part of this work (concerns with the study of the production of bio-oil in fast pyrolysis conditions in a gas / solid reactor. To establish a relationship between the operating conditions and chemical composition of pyrolysis bio-oil, a tool for meaningfull comparison of experiments was developed. Experiments have shown that the yield and composition of pyrolysis oil depends mainly on the composition of wood, the heating rate and the effective residence time of the wood particles into the reactor

A non-reactive model system comprising a highly concentrated and unstable oil-in-water emulsion was used to investigate the retention of oil by the membrane in producing biodiesel with a membrane reactor. Critical flux was identified using the relationship between the permeate flux and transmembrane pressure along with the separation efficiency of the membrane. It was shown that separation efficiencies above 99.5% could be obtained at all operating conditions up to the critical flux. It was observed that the concentration of oil in all collected permeate samples using the oil-water system was below 0.2 wt% when operating at a flux below the critical flux. Studies to date have been limited to the characterization of low concentrated emulsions below 15 vol.%. The average oil droplet size in highly concentrated emulsions was measured as 3200 nm employing direct light scattering (DLS) measurement methods. It was observed that the estimated cake layer thickness of 20 to 80 mm was larger than external diameter of the membrane tube i.e. 6 mm based on a large particle size. Settling of the concentrated emulsion permitted the detection of a smaller particle size distribution (30-100 nm) within the larger particles averaging 3200 nm. It was identified that DLS methods could not efficiently give the droplet size distribution of the oil in the emulsion since large particles interfered with the detection of smaller particles. The content of the smaller particles represented 1% of the total weight of oil at 30°C and 5% at 70°C. This was too low to be detected using DLS measurements but was sufficient to affect ultrafiltration. In order to study the critical flux in the presence of transesterification reaction and the effect of cross flow velocity on separation, various oils were transesterified in another membrane reactor providing higher cross flow velocity. higher cross flow velocity provides better separation by reducing materials deposition on the surface of the membrane due to higher shearing. The oils tested were canola, corn, sunflower and unrefined soy oils (Free Fatty Acids (FFA< 1%)), and waste cooking oil (FFA= 9%). The quality of all biodiesel samples was studied in terms of glycerine, mono-glyceride, di-glyceride and tri-glyceride concentrations. The composition of all biodiesel samples were in the range required by ASTM D6751 and EN 14214 standards. A critical flux based on operating pressure in the reactor was reached for waste cooking and pre-treated corn oils. It was identified that the reaction residence time in the reactor was an extremely important design parameter affecting the operating pressure in the reactor.
Natural Sciences and Engineering Research Council of Canada (NSERC)

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Sob certas hipóteses simplificadoras, o modelo matemático que descreve o escoamento de água e óleo em reservatórios de petróleo pode ser representado por um sistema não linear de Equações Diferenciais Parciais composto por uma equação elíptica de pressão (fluxo) e uma equação hiperbólica de saturação (transporte). Devido a complexidades na modelagem de ambientes deposicionais, nos quais são incluídos camadas inclinadas, canais, falhas e poços inclinados, há uma dificuldade de se construir um modelo que represente adequadamente certas características dos reservatórios, especialmente quando malhas estruturadas são usadas (cartesianas ou corner point). Além disso, a modelagem do escoamento multifásico nessas estruturas geológicas incluem descontinuidades na variável e instabilidades no escoamento, associadas à elevadas razões de mobilidade e efeitos de orientação de malha. Isso representa um grande desafio do ponto de vista numérico. No presente trabalho, uma formulação fundamentada no Método de Volumes Finitos é estudada e proposta para discretizar as equações elíptica de pressão e hiperbólica de saturação. Para resolver a equação de pressão três formulações robustas, com aproximação dos fluxos por múltiplos pontos são estudadas. Essas formulações são abeis para lidar com tensores de permeabilidade completos e malhas poligonais arbitrárias, sendo portanto uma generalização de métodos mais tradicionais com aproximação do fluxo por apenas dois pontos. A discretização da equação de saturação é feita com duas abordagens com característica multidimensional. Em uma abordagem mais convencional, os fluxos numéricos são extrapolados diretamente nas superfícies de controle por uma aproximação de alta resolução no espaço (2ª a 4ª ordem) usando uma estratégia do tipo MUSCL. Uma estratégia baseada na Técnica de Mínimos Quadrados é usada para a reconstrução polinomial. Em uma segunda abordagem, uma variação de uma esquema numérico Verdadeiramente Multidimensional é proposto. Esse esquema diminui o efeito de orientação de malha, especialmente para malhas ortogonais, mesmo embora alguma falta de robustez possa ser observada pra malhas excessivamente distorcidas. Nesse tipo de formulação, os fluxos numéricos são calculados de uma forma multidimensional. Consiste em uma combinação convexa de valores de saturação ou fluxo fracionário, seguindo a orientação do escoamento através do domínio computacional. No entanto, a maioria dos esquemas numéricos achados na literatura tem aproximação apenas de primeira ordem no espaço e requer uma solução implícita de sistemas algébricos locais. Adicionalmente, no presente texto, uma forma modificada desses esquemas “Verdadeiramente” Multidimensionais é proposta em um contexto centrado na célula. Nesse caso, os fluxos numéricos multidimensionais são calculados explicitamente usando aproximações de alta ordem no espaço. Para o esquema proposto, a robustez e o caráter multidimensional também leva em conta a distorção da malha por meio de uma ponderação adaptativa. Essa ponderação regula a característica multidimensional da formulação de acordo com a distorção da malha. Claramente, os efeitos de orientação de malha são reduzidos. A supressão de oscilações espúrias, típicas de aproximações de alta ordem, são obtidas usando, pela primeira vez no contexto de simulação de reservatórios, uma estratégia de limitação multidimensional ou Multidimensional Limiting Process (MLP). Essa estratégia garante soluções monótonas e podem ser usadas em qualquer malha poligonal, sendo naturalmente aplicada em aproximações de ordem arbitrária. Por fim, de modo a garantir soluções convergentes, mesmo para problemas tipicamente não convexos, associados ao modelo de Buckley-Leverett, uma estratégia robusta de correção de entropia é empregada. O desempenho dessas formulações é verificado com a solução de problemas relevantes achados na literatura.
Under certain simplifying assumptions, the problem that describes the fluid flow of oil and water in heterogeneous and anisotropic petroleum reservoir can be described by a system of non-linear partial differential equations that comprises an elliptic pressure equation (flow) and a hyperbolic saturation equation (transport). Due to the modeling of complex depositional environments, including inclined laminated layers, channels, fractures, faults and the geometrical modeling of deviated wells, it is difficult to properly build and handle the Reservoir Characterization Process (RCM), particularly by using structured meshes (cartesian or corner point), which is the current standard in petroleum reservoir simulators. Besides, the multiphase flow in such geological structures includes the proper modeling of water saturation shocks and flow instabilities associated to high mobility ratios and Grid Orientation Effects (GOE), posing a great challenge from a numerical point of view. In this work, a Full Finite Volume Formulation is studied and proposed to discretize both, the elliptic pressure and the hyperbolic saturation equations. To solve the pressure equation, we study and use three robust Multipoint Flux Approximation Methods (MPFA) that are able to deal with full permeability tensors and arbitrary polygonal meshes, making it relatively easy to handle complex geological structures, inclined wells and mesh adaptivity in a natural way. To discretize the saturation equation, two different multidimensional approaches are employed. In a more conventional approach, the numerical fluxes are extrapolated directly on the control surfaces for a higher resolution approximation in space (2nd to 4th order) by a MUSCL (Monotone Upstream Centered Scheme for Conservation Laws) procedure. A least squares based strategy is employed for the polynomial reconstruction. In a second approach, a variation of a “Truly” Multidimensional Finite Volume method is proposed. This scheme diminishes GOE, especially for orthogonal grids, even though some lack of robustness can be observed for extremely distorted meshes. In this type of scheme, the numerical flux is computed in each control surface in a multidimensional way, by a convex combination of the saturation or the fractional flow values, following the approximate wave orientation throughout the computational domain. However, the majority of the schemes found in literature is only first order accurate in space and demand the implicit solution of local conservation problems. In the present text, a Modified Truly Multidimensional Finite Volume Method (MTM-FVM) is proposed in a cell centered context. The truly multidimensional numerical fluxes are explicitly computed using higher order accuracy in space. For the proposed scheme, the robustness and the multidimensional character of the aforementioned MTM-FVM explicitly takes into account the angular distortion of the computational mesh by means of an adaptive weight, that tunes the multidimensional character of the formulation according to the grid distortion, clearly diminishing GOE. The suppression of the spurious oscillations, typical from higher order schemes, is achieved by using for the first time in the context of reservoir simulation a Multidimensional Limiting Process (MLP). The MLP strategy formally guarantees monotone solutions and can be used with any polygonal mesh and arbitrary orders of approximation. Finally, in order to guarantee physically meaningful solutions, a robust “entropy fix” strategy is employed. This produces convergent solutions even for the typical non-convex flux functions that are associated to the Buckley-Leverett problem. The performance of the proposed full finite volume formulation is verified by solving some relevant benchmark problems.

Neste trabalho apresentamos um esquema numérico para a simulação computacional de escoamentos bifásicos, água-óleo, em reservatórios de petróleo. O modelo matemático consiste em um sistema de equações diferenciais parciais não-linear nas incógnitas velocidade, pressão e saturação. Uma quebra de operadores a dois níveis possibilita uma maior eficiência ao método permitindo que a velocidade, fornecida pelo problema de velocidade-pressão, seja atualizada somente para determinados intervalos de tempo associados ao problema de transporte advectivo-difusivo em termos da saturação. O método dos volumes finitos é empregado na resolução numérica do problema de velocidade-pressão e do transporte de massa por advecção e difusão. Na solução do problema de transporte de massa utilizamos limitadores de fluxo na aproximação dos termos advectivos e diferenças centradas para os termos difusivos. O nosso simulador foi validado a partir de confrontações dos seus resultados com as soluções teóricas conhecidas para os problemas unidimensionais, equações de Burgers e de Buckley-Leverett, e com outros resultados numéricos em se tratando do escoamento bifásico água-óleo bidimensional em meios porosos heterogêneos.
A new numerical method is proposed for the solution of two-phase flow problem in petroleum reservoirs. The two-phase (water and oil) flow problem is governed by a pressure-velocity equation coupled to a saturation equation. For computational eficiency an operator spliting technique is used; distinct time steps can be used for the computation of transport and pressure-velocity problems. The finite volume method is used in the numerical solution of the velocity-pressure and mass transport problems. A flux limiter is used for the numerical discretization of the advective terms while centered schemes are employed for the diffusion terms in the mass transport problem. In the validation of our numerical method we compared numerical and theoretical solutions for one dimensional problems, Burgers and Buckley-Leverett equations, and compared our numerical results to others, in the case of oil-water flows in two dimensions for an heterogeneous porous media.

The content of this thesis is the design layout and construction of the building of new fire station in South Moravian Region. It is an object split into two interconnected parts: administrative - two-storey, basementless garage for trucks - single-storey, basementless The object is used to perform the services of eight firefighters per shift and one full-time worker. Architecture was chosen so that the object is functionally meet the requirements of firefighters on duty at both organizational (work on PS) and at the operational (exit) procedure. The building is covered with a flat roof, attic walled building on the peripheral wall with white facade and symbols accentuating the purpose of the building. The inner workings of the object are designed to meet the performance demands of service 24ti - hour shifts. The building is brick, based on the footings and load distribution base. The roof structure is made of reinforced concrete load-bearing concrete slab with heat-waterproofing layers classical arrangement of layers. The building is insulated ETICS. This - the operational part is located on the 1st and 2nd floor of the south-western part of the building, single-storey garage built for trucks in the northeastern part.

Dans l’industrie, les fabricants tendent à limiter la lubrification conventionnelle lors de l’usinage et s’orientent de plus en plus vers la microlubrification (MQL : Minimum Quantity Lubrication) pour des raisons économiques, écologiques et pour respecter la santé des opérateurs. Une très faible quantité de lubrifiant de faible pression nécessite une conception optimale des canaux internes de l’outil afin de limiter les pertes de charges et avoir les avantages de la microlubrification. Premièrement, une revue bibliographique introduit l’étude en présentant les avantages qu’induit le passage à la microlubrification. Par la suite, quelques conceptions d’outils avec une lubrification interne qui vise la face de coupe ou la face de dépouille de la plaquette sont passées en revue
In machining industry, manufacturers tend to limit conventional lubrication and are moving increasingly towards Minimum Quantity Lubrication (MQL) for economic and ecological reasons, and with a view to safeguarding operator health and safety. A very small amount of lubricant at low pressure requires optimized design of the tools internal channels in order to minimize pressure drops and gain benefit from MQL. First, a literature review introduces the study by presenting the benefits induced by switching to MQL. Thereafter, some tool designs with internal lubrication for rake face or flank face lubrication are presented

 Acorus calamus L. је вишегодишња зељаста биљка влажних подручја, чија су лековита својства одавно позната. Дрогу иђирота чини ризом који се употребљава као чај, прах, сок, гел, уље или крема. Због прекомерне експлоатације и високог степена угрожености ове дивље лековите биљне врсте у Србији је уведена забрана његовог сакупљања из природе. Да би се задовољила повећана потражња од стране индустрија које га користе, гајење иђирота се намеће као једно од најпрагматичнијих решења. За потребе утврђивање начина гајења, прво се приступило истраживању услова успевања и варирање својстава иђирота са пет локалитета природних станишта: Обедска бара, Делиблатска пешчара, Засавица, Раковац и Дубовац. Потом је заснован двогодишњи пољски оглед на ком је испитиван утицај примене основних агротехничких мера, односно густине садње и ђубрења азотом, на својства биљака. Оглед је постављен 2013. године, на подручју засеока Ћумуране у насељу Рипањ. Код биљка са природних станишта и са огледног поља праћена су следећа својства: висина биљака, дужина ризома, број и дужина бочних грана на ризому, број пупољака на ризому и бочним гранама, број нодуса на ризому и бочним гранама, проценат суве материје ризома, маса свежег и сувог ризома, однос масе свежег и сувог ризома. Код гајених биљака праћен је и принос свежег и сувог ризома. Код свих узорака иђирота испитиван је садржај и састав етарског уља из ризома. Идентификоване су, такође, најзаступљеније компоненте и утврђен је садржаја β-азарона. За утврђивање нивоа плоидије популација из Србије рађено је пребројавање хромозома. Испитивањем биљака са природних станишта, констатовано је да на већину њихових морфолошких одлика, локалитет није имао утицаја. Утицај локалитета испољен је само на: број нодуса на ризому (највећи је био у Дубовцу - 58 а најмањи на Обедској бари - 15), проценат суве материје (највећи је био у Раковцу - 50,2%, а најмањи на Делиблатској пешчари - 37,9%) и однос масе свежег и сувог ризома (највећи је на Делиблатској пешчари - 2,64, а најмањи у Раковцу - 1,90). У пољском огледу добијени су следећи резултати: висина биљака је била највећа при најмањој густини усева (35000 биљака/ha) и најмањој дози азота (60 kg/ha) дужина ризома, као и број и дужина њихових бочних грана су највећи при средњој густини садње (48000 биљака/ha) и најмањој дози азота; број пупољака на ризому има највећу вредност при најмањој густини садње и најмањој дози азота. Број пупољака прве бочне гране је био највећи на највећој густини садње (62000 биљака/ha) и при најмањој дози азота, а број нодуса на ризому није зависио од густине садње, као ни од доза ђубрења. Највећа маса свежег и сувог ризома остварена је при средњој густини садње (48000 биљака/ha) и најмањој (62000 биљака/ha) дози азота, док је проценат суве материје био највећи при највећој густини и најмањој дози азота (60 kg/ha). На однос масе свежег и сувог ризома утицај нису имали ни ђубрење ни густинасадње усева, док су приноси свежег и сувог ризома били највећи на највећој густини садње и при најмањој дози азота. Садржај етарског уља иђирота из природе није показао значајна одступања између локалитета. Садржај етарског уља ризома гајеног иђирота опадао је са порастом густине садње, док различите дозе азота нису утицале на ову особину. Максимална концентрација β-азарона у етарском уљу иђирота са природног станишта била је 17,07 % (локалитет Раковац), док је највећи садржај β-азарона код гајеног иђирота био 21,41 %. Повећана концентрација β- азарона се објашњава интензивнијим метаболизмом азота, због повећане количине из ђубрива. обијени резултати потврђују да је концентрација β-азарона у етарском уљу ризома иђирота слична резултатима из других земаља Европе. Бројањем хромозома утврђено је да иђирот припада триплоидном, европском варијетету Аcоrus cаlаmus vаr. cаlаmus.
 Acorus calamus L. je višegodišnja zeljasta biljka vlažnih područja, čija su lekovita svojstva odavno poznata. Drogu iđirota čini rizom koji se upotrebljava kao čaj, prah, sok, gel, ulje ili krema. Zbog prekomerne eksploatacije i visokog stepena ugroženosti ove divlje lekovite biljne vrste u Srbiji je uvedena zabrana njegovog sakupljanja iz prirode. Da bi se zadovoljila povećana potražnja od strane industrija koje ga koriste, gajenje iđirota se nameće kao jedno od najpragmatičnijih rešenja. Za potrebe utvrđivanje načina gajenja, prvo se pristupilo istraživanju uslova uspevanja i variranje svojstava iđirota sa pet lokaliteta prirodnih staništa: Obedska bara, Deliblatska peščara, Zasavica, Rakovac i Dubovac. Potom je zasnovan dvogodišnji poljski ogled na kom je ispitivan uticaj primene osnovnih agrotehničkih mera, odnosno gustine sadnje i đubrenja azotom, na svojstva biljaka. Ogled je postavljen 2013. godine, na području zaseoka Ćumurane u naselju Ripanj. Kod biljka sa prirodnih staništa i sa oglednog polja praćena su sledeća svojstva: visina biljaka, dužina rizoma, broj i dužina bočnih grana na rizomu, broj pupoljaka na rizomu i bočnim granama, broj nodusa na rizomu i bočnim granama, procenat suve materije rizoma, masa svežeg i suvog rizoma, odnos mase svežeg i suvog rizoma. Kod gajenih biljaka praćen je i prinos svežeg i suvog rizoma. Kod svih uzoraka iđirota ispitivan je sadržaj i sastav etarskog ulja iz rizoma. Identifikovane su, takođe, najzastupljenije komponente i utvrđen je sadržaja β-azarona. Za utvrđivanje nivoa ploidije populacija iz Srbije rađeno je prebrojavanje hromozoma. Ispitivanjem biljaka sa prirodnih staništa, konstatovano je da na većinu njihovih morfoloških odlika, lokalitet nije imao uticaja. Uticaj lokaliteta ispoljen je samo na: broj nodusa na rizomu (najveći je bio u Dubovcu - 58 a najmanji na Obedskoj bari - 15), procenat suve materije (najveći je bio u Rakovcu - 50,2%, a najmanji na Deliblatskoj peščari - 37,9%) i odnos mase svežeg i suvog rizoma (najveći je na Deliblatskoj peščari - 2,64, a najmanji u Rakovcu - 1,90). U poljskom ogledu dobijeni su sledeći rezultati: visina biljaka je bila najveća pri najmanjoj gustini useva (35000 biljaka/ha) i najmanjoj dozi azota (60 kg/ha) dužina rizoma, kao i broj i dužina njihovih bočnih grana su najveći pri srednjoj gustini sadnje (48000 biljaka/ha) i najmanjoj dozi azota; broj pupoljaka na rizomu ima najveću vrednost pri najmanjoj gustini sadnje i najmanjoj dozi azota. Broj pupoljaka prve bočne grane je bio najveći na najvećoj gustini sadnje (62000 biljaka/ha) i pri najmanjoj dozi azota, a broj nodusa na rizomu nije zavisio od gustine sadnje, kao ni od doza đubrenja. Najveća masa svežeg i suvog rizoma ostvarena je pri srednjoj gustini sadnje (48000 biljaka/ha) i najmanjoj (62000 biljaka/ha) dozi azota, dok je procenat suve materije bio najveći pri najvećoj gustini i najmanjoj dozi azota (60 kg/ha). Na odnos mase svežeg i suvog rizoma uticaj nisu imali ni đubrenje ni gustinasadnje useva, dok su prinosi svežeg i suvog rizoma bili najveći na najvećoj gustini sadnje i pri najmanjoj dozi azota. Sadržaj etarskog ulja iđirota iz prirode nije pokazao značajna odstupanja između lokaliteta. Sadržaj etarskog ulja rizoma gajenog iđirota opadao je sa porastom gustine sadnje, dok različite doze azota nisu uticale na ovu osobinu. Maksimalna koncentracija β-azarona u etarskom ulju iđirota sa prirodnog staništa bila je 17,07 % (lokalitet Rakovac), dok je najveći sadržaj β-azarona kod gajenog iđirota bio 21,41 %. Povećana koncentracija β- azarona se objašnjava intenzivnijim metabolizmom azota, zbog povećane količine iz đubriva. obijeni rezultati potvrđuju da je koncentracija β-azarona u etarskom ulju rizoma iđirota slična rezultatima iz drugih zemalja Evrope. Brojanjem hromozoma utvrđeno je da iđirot pripada triploidnom, evropskom varijetetu Acorus calamus var. calamus.
  Acorus calamus L. is a perennial herbaceous plant found in wet areas, whose medicinal properties have been long known. The drug of sweet flag is made from the rhizome which is used as tea, powder, juice, gel, oil or cream. Because of overexploitation and the high degree of endangerment of this wild medicinal plant species in Serbia collecting was banned. In order to meet the increased demand for this plant by industries that use it, cultivation of sweet flag is emerging as one of the most pragmatic solutions. For the purpose of determining the method for plant growth, the first approach was studying the growing conditions and the variation of properties of sweet flag from five natural habitats: Obedska pond, Deliblato Sands, Zasavica, Rakovac and Dubovac.After that a two-year field experiment was designed in which the effect of application of basic agrotechnical measures, i.e., different planting density and doses of nitrogen fertilization on the plants, was studied. The experiment was set up in 2013, in the area of the hamlet Ćumurana in the settlement Ripanj. In plants from natural habitats and the experiment, the following properties were measured: the height of the plants, the length of the rhizome, the number and length of lateral branches on the rhizome, the number of buds on the rhizome and lateral branches, the number of leaf scars on the rhizome and lateral branches, the percentage of dry matter of the rhizome, the mass of the fresh and the dry rhizome, the ratio of mass between the fresh and the dry rhizome. In the experiment with cultivated plants, the yield of the fresh and the dry rhizome was also measured. For all samples of sweet flag, the content and composition of the essential oil from the rhizome was measured. Also, the main components were identified and the content of the β-asarone was determined. For the purposes of identifying the ploidy, i.e., which varieties the sweet flag from Serbia belongs to, counting of chromosomes was done. By examining plants from natural habitats, it was noted that the site had no influence on the majority of morphological features of plants. The impact of the sites was manifested only in the number of leaf scars (the largest number was in Dubovac-58,0 and the smallest number was in Obedska pond-15,0), percentage of dry matter (the largest percentage was in Rakovac-50.2% and the smallest percentage was in Deliblato Sands-37,9 %) and the ratio of mass between a fresh and a dry rhizome (the largest ratio was in Deliblato Sands-2,6 and the smallest ratio was in Rakovac-2,2). In the field experiment, the following results were obtained: the height of the plants is the largest at the lowest planting density (35000 plants/ha) and lowest nitrogen dosage (60 kg/ha), the length of the rhizome, as well as number and length of lateral branches of the rhizome are largest at medium planting density (48000 plants/ha) and the lowest dosage of nitrogen (60 kg/ha), the number of buds on the rhizome has the highest value at the lowest planting density (35000 plants/ha) and the lowest dosage of nitrogen (60 kg/ha). The number of buds on the first lateral branch was largest at the largest planting density (62000 plants/ha) and the lowest dosage of nitrog (60 kg/ha) , and the number of leaf scars on the rhizome doesnot depend on the planting dosage or the dosage of fertilizing. The largest mass of the fresh and the dry rhizome is accomplished at medium planting density and the lowest dosage of nitrogen, while the percentage of dry matter was largest at the largest density and the lowest dosage of nitrogen. The fertilization and the crop density had no effect on the ratio of mass between the fresh and the dry rhizome, while the yields of the fresh and the dry rhizome were largest at the largest planting density and the lowest dosage of nitrogen. The content of essential oils of natural sweet flag showed no significant discrepancies between the sites. The content of essential oil of cultivated sweet flag rhizomes declined with the increase of planting density, while different nitrogen doses had no effect on this property. The maximum concentration of β-asarones in the essential oil of natural sweet flag was 17,07 % (Rakovac), while the largest content of β-asarones in cultivated sweet flag was 21,41 %. The larger concentration of β-asarones is explained through increased nitrogen metabolism, because of increased amounts of fertilizer. The results confirm that the concentration of β-asarone in the essential oil of sweet flag rhizomes is similar to the concentration of essential oil of sweet flag rhizomes from Europe. By counting the chromosomes it is established that sweet flag belongs to the triploid, European variety of Аcоrus cаlаmus vаr. cаlаmus.

This thesis draws on David Harvey’s concept of “accumulation by dispossession” and an international political economy (IPE) approach centred on the institutional arrangements and power structures that privilege certain actors and values, in order to critique current capitalist practices of primitive accumulation by the global corporate extractive industry. The thesis examines how accumulation by dispossession by the global extractive industry is facilitated by the “free entry” or “free mining” principle. It does so by focusing on Canada as a leader in the global extractive industry and the spread of this country’s mining laws to other countries – in other words, the transnationalisation of norms in the global extractive industry – so as to maintain a consistent and familiar operating environment for Canadian extractive companies. The transnationalisation of norms is further promoted by key international institutions such as the World Bank, which is also the world’s largest development lender and also plays a key role in shaping the regulations that govern natural resource extraction. The thesis briefly investigates some Canadian examples of resource extraction projects, in order to demonstrate the weaknesses of Canadian mining laws, particularly the lack of protection of landowners’ rights under the free entry system and the subsequent need for “free, prior and informed consent” (FPIC). The thesis also considers some of the challenges to the adoption and implementation of the right to FPIC. These challenges include embedded institutional structures like the free entry mining system, international political economy (IPE) as shaped by international institutions and powerful corporations, as well as concerns regarding ‘local’ power structures or the legitimacy of representatives of communities affected by extractive projects. The thesis concludes that in order for Canada to be truly recognized as a leader in the global extractive industry, it must establish legal norms domestically to ensure that Canadian mining companies and residents can be held accountable when there is evidence of environmental and/or human rights violations associated with the activities of Canadian mining companies abroad. The thesis also concludes that Canada needs to address underlying structural issues such as the free entry mining system and implement FPIC, in order to curb “accumulation by dispossession” by the extractive industry, both domestically and abroad.

Aflatoxins (AFs) are highly toxic second metabolites produced by Aspergillus flavus and A. parasiticus. They are widely detected in cereals, spices, and drinks worldwide. Aflatoxin contamination of foods and crops poses a high health risk for humans and livestock. It is well known that environmental conditions and substrates could influence fungal growth and aflatoxin production. This study tested the effect of water activity (0.82, 0.86, 0.90, 0.94, and 0.98 a_w) and incubation temperatures (20°, 27°, and 35°C) on the growth and aflatoxin production of A. flavus and A. parasiticus on ground flax seeds and ground niger seeds. The effect of oil contents of ground niger seeds on fungal growth and aflatoxin production was also investigated in this study.

These two fungal species could not grow on any of the tested substrates with 0.82 a_w at 20°, 27°, or 35°C. Aspergillus flavus grew most rapidly on flax seeds with 0.90 a_w at 27°C and also 0.94 a_w at 27° or 35°C. However, on niger seeds, A. flavus grew best at 0.90 or 0.94 a_w incubated at 35°C as well as at 0.94 or 0.98 a_w incubated at 27°C. Aspergillus parasiticus showed the optimum growth on flax seeds with 0.90 a_w at 35°C, whereas on niger seeds, the optimum occurred on seeds with 0.90 a_w at 35°C and also on seeds with 0.94 a_w at 27° or 35°C. The optimum conditions for A. flavus to produce high levels of aflatoxins (270-299 μg/kg) on flax seeds were 0.90 a_w at 35°C; whereas, the optimum conditions for A. flavus to produce aflatoxin (203-278 μg/kg) on niger seeds were 0.90 or 0.98 a_w at 27°C and also 0.90 a_w at 35°C. Aspergillus parasiticus produced high levels of aflatoxins (284-365 μg/kg) on flax seeds under the following three conditions, 0.86 or 0.98 a_w at 35°C and 0.94 a_w at 27°C; A. parasiticus produced 200-384 μg/kg of aflatoxins on niger seeds under nine out of 12 tested incubation conditions.

Reducing mean oil contents from 35.2 to 10.5% of ground niger seeds had very little effect on the growth of the two fungi but significantly decreased their aflatoxin production under certain incubation conditions. On de-oiled niger seeds inoculated with A. flavus, only 13μg/kg of AFB1 was found on seeds with 0.94 a_w at 27°C; whereas, on de-oiled niger seeds inoculated with A. parasiticus, high levels of aflatoxins (245-345 μg/kg) were only detected under the three following incubation conditions, 0.90 or 0.94 a_w at 27°C, and 0.86 a_w at 35°C.

This study showed that the optimum growth and aflatoxin production by A. flavus and A. parasiticus were not identical and influenced by incubation conditions, including temperature, water activity, and growth substrates. The results of this study could help establish guidelines for post-harvest and storage conditions for oil seeds to prevent fungal growth and aflatoxin formation.

Захист відбудеться 24 грудня 2019 р. о 14.00 годині на засіданні екзаменаційної комісії №18 у Тернопільському національному технічному університеті імені Івана Пулюя за адресою: 46000, м. Тернопіль, вул. Танцорова, 5, навчальний корпус №5, ауд. 14.
Витрикуш Ю.А. Тема: «Розробка і створення біологічно активної харчової добавки із збалансованим співвідношенням жирних кислот родини омега». – Рукопис. Дослідження на здобуття освітньо-кваліфікаційного рівня магістра за спеціальністю 181 «Харчові технології та інженерія». – Тернопільський національний технічний університет імені Івана Пулюя, Тернопіль, 2019. Магістерська кваліфікаційна робота присвячена розробці купажованих олій на основі кукурудзяної, лляної, ріпакої та оливкової олії, які у відомих пропорціях забезпечать оптимальне співвідношення між ПНЖК родин омега-3, -6 та -9. Метою є розробка купажованих олій як біологічно активних харчових добавок з оптимальним балансом ненасичених жирних кислот, зокрема з високим вмістом поліненасичених родини ω-3. На основі одержаних результатів запропонована суміш конопляної, лляної, соєвої та ріпакої олії у співвідношенні 60 : 20 : 10 : 10. із збалансованим співвідношенням поліненасичених жирних кислот родини ω-3, ω-6 і ω-9, яке становило 1 : 2,4 : 2,4 Ключові слова: кукурудзяна, лляна, оливкова і ріпакова олії, купаж, жирнокислотний склад, поліненасичені жирні кислоти
Vytrykush J. А. Theme: "Development of a bioactive food additive with the most suitable balance of fatty acids of omega family". - Manuscript. Research on obtaining a master's qualification level in the specialty 181 "Food Technology and Engineering". Ternopil by Ivan Puluj National Technical University, Ternopil, 2019. The master's qualification is dedicated to the development of blended oils based on corn, linseed, rapeseed and olive oil, which in known proportions will provide the optimal ratio between PUFAs of omega-3, -6 and -9 families. The aim is to develop blended oils as biologically active food additives with an optimal balance of unsaturated fatty acids, in particular with a high content of polyunsaturated ω-3 family. Based on the results obtained, a mixture of hemp, flax, soybean and rapeseed oil in the ratio of 60: 20: 10: 10. with a balanced ratio of polyunsaturated fatty acids of the family ω-3, ω-6 and ω-9 was proposed, which was 1: 2,4 : 2.4 Keywords: corn, flax, olive and rapeseed oil, blend, fatty acid composition, polyunsaturated fatty acids
Вступ 1. Огляд літератури. Харчові добавки з різним вмістом поліненасичених жирних кислот родин омега-3, -6 та-9 1.1. Купажі олій як нові функціональні харчові продукти 1.2. Характеристика ринку купажованих олій 1.3. Біологічна і харчова цінність олій як джерел омега кислот 1.4. Метаболізм поліненасичених жирних кислот в організмі 1.4.1. Метаболізм ПНЖК родини ώ-6 1.4.2. Метаболізм ПНЖК родини ώ-6 2. Матеріали і методи досліджень 2.1. Схема досліджень 2.2. Дослідження жирнокислотного складу олій і їх купажів 3. Результати власних досліджень та їх обговорення 3.1. Жирнокислотний склад кукурудзяної, лляної, ріпакової і оливкової олії 3.2. Жирнокислотний склад купажованих олій 4. Охорона праці та безпеки у надзвичайних ситуаціях 4.1. Охорона праці 4.2. Безпека в надзвичайних ситуаціях 5. Екологія 5.1 Екологічна безпека харчових продуктів 65Економічна ефективність Висновки і пропозиції виробництву Список використаної літератури Додатки

Зміни в раціоні харчування, що відбулись напротязі останніх десятиліть і характеризуються споживанням надмірної кількості рафінованих та висококалорійних продуктів негативно впливають на функціонування організму, здоровя внутрішніх органів та шкіри людини. Спричинене це низьким вмістом харчових волокон, поліненасичених жирних кислот, рослинного білка, мінеральних речовин та вітамінів, і довготривале їх обмеження може спричинити низку так званих «цивілізаційних хвороб», які в сиву давнину не мали місця в житті молодого і працездатного населення, а останнім часом усе частіше спостерігаються власне у молоді. І одним з важливих завдань для харчової промисловості є забезпечення балансу поживних речовин для функціонування організму людини і попередження розвитку небажаних хвороб молодого населення. В сучасному вищезгаданому раціоні, багатому в Омега 6 та Омега 9 жирні кислоти власне чітко спостерігається потреба в Омега 3 жирних кислотах, для нормалізування балансу Омега 3-6-9 жирних кислот в організмі людини. А отже одним з найбільш перспективних напрямків є збагачення популярних харчових продуктів, таких як хліб та хлібні вироби, поліненасиченими жирними кислотами, а зокрема альфа-ліноленовою (ALA) кислотою, що є одною з основних Омега 3 поліненасичених жирних кислот, яку можна отримати з продукції рослинного походження. Найбільш поширеним джерелом якої є льон, а зокрема лляна олія та насіння льону, багате в олії і складається всередньому в 50% з ALA. Сьогодні пшеничне борошно є чи не найбільш розповсюдженою сировиною для виробництва хліба та хлібних виробів, а паляниця українська - це традиційний український хлібний виріб, плеската кругла хлібина, з переважним вмістом пшеничного борошна. Поверхня хлібини трішки мучиста з хрусткою скоринкою-козирком, яка утворюється внаслідок надрізу на хлібі перед випічкою, яка є символом культури, гостинності, прихильності, обереговим та ритуальним знаком. А отже покращувати раціон харчування на її базі – це чудова можливість для збагачення раціону харчування поживними речовинами і забезпечення здоровя населення.
Changes in the diet that have occurred in recent decades and are characterized by the consumption of excessive amounts of refined and high-calorie foods adversely affect the functioning of the body, the health of internal organs and skin. This is due to the low content of dietary fiber, polyunsaturated fatty acids, vegetable protein, minerals and vitamins, and their long-term restriction can cause a number of so-called "civilizational diseases", which in ancient times did not occur in young and able-bodied people. they are more and more often observed in young people. And one of the important tasks for the food industry is to ensure the balance of nutrients for the functioning of the human body and prevent the development of unwanted diseases in young people. In the modern above-mentioned diet, rich in Omega 6 and Omega 9 fatty acids, the need for Omega 3 fatty acids is clearly observed to normalize the balance of Omega 3-6-9 fatty acids in the human body. Therefore, one of the most promising areas is the enrichment of popular foods, such as bread and bakery products, with polyunsaturated fatty acids, in particular alpha-linolenic (ALA) acid, which is one of the main Omega 3 polyunsaturated fatty acids that can be obtained from products of vegetable origin. The most common source of which is flax, in particular flaxseed oil and flaxseed, which is rich in oil and consists of an average of 50% ALA. Today, wheat flour is perhaps the most common raw material for the production of bread and bakery products, and Ukrainian palyanitsa is a traditional Ukrainian bread product, flat bread, with a predominant content of wheat flour. The surface of the bread is a bit floury with a crispy crust-visor, which is formed as a result of an incision on the bread before baking, which is a symbol of culture, hospitality, affection, a precautionary and ritual sign. Therefore, improving the diet based on it is a great opportunity to enrich the diet with nutrients and ensure the health of the population.
РЕФЕРАТ ВСТУП 1. ОГЛЯД ЛІТЕРАТУРИ. 1.1. Сучасна ситуація на ринку виробників хлібобулочних виробів. 1.2. Формування нового асортименту хлібобулочних виробів. 1.3. Сучасні харчові тенденції населення. 1.4. Продукти на основі інгредієнтів, багатих на омега-3 жирні кислоти. 1.5. Сучасні проблеми харчування та потенційне застосування льону в їх вирішенні. 1.6. Популярні високоякісні джерела омега 3. 1.7. Хлібопекарський виріб, паляниця українська 2. ДОСЛІДЖЕННЯ. АНАЛІЗ НОВІТНІХ МЕТОДІВ ПОКРАЩЕННЯ ХАРЧОВИХ ПРОДУКТІВ. 2.1. Їжа і її вплив на організм. 2.2. Особливості обміну речовин в організмі. 2.3. Омега 3, та інші поліненасичені жирні кислоти. 2.4. Льон та його вплив на організм. 2.5. Нові методи збагачення продуктів поліненасиченими жирними кислотами омега 3. 2.6. Функціональна їжа 3. ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ. 4. ВИСНОВКИ БІБЛІОГРАФІЯ ДОДАТКИ

Thesis (Ph. D.)--University of Alberta, 2010.
Title from pdf file main screen (viewed on June 11, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering, [Department of] Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

Canada has the largest known reserve of oil in the world in the form of oil sands: an estimated 1.7 to 2.5 trillion barrels of oil are deposited in combination of the sand, water and clay. The presented research is devoted to bubble-solid surface interaction, which is one of the critical areas of the oil sand processing and it is also a key point for many other processing technologies, such as mineral recovery, froth flotation, soil remediation, de inking of paper, heat transfer in boilers tube, biological and medical sciences. The goal of this work was to investigate new theoretical and practical approaches, which would help in better understanding of fundamentals of the flotation process in oil sands extraction. Among many achievements of this research are: 1)development of the method for generation of a single micro bubble. Dependence of this process on micropipette tip size and inclination, gas type, taper length and other parameters has also been studied (Chapter 3); 2)study of gas bubble - flat surface interactions based on a practical approach of determination of two dynamic parameters, sliding velocity and induction time of a gas bubble. Various types of gas bubbles (CO2, Air, H2, and O2) and collector surfaces (bitumen, treated hydrophobic and hydrophilic silica) were used in sliding velocity and induction time measurements. The sliding velocity of gas bubbles under an inclined collector surface was found to be in a strong dependence of water chemistry, type of gases, temperature, initial separation between bubble and collector surface (Chapter 4); 3)developing an analytical model for predicting bubble sliding velocity based on previously developed models. The model was in a good agreement with experimental results (Chapter 5); 4)establishing a new method for bubble zeta potential measurements. The measurements were in a good agreement with previously studies reported in literature (Chapter 6). Summarized above findings from this research represent valuable advances in understanding oil sands processing. The prospects of future work are provided in Chapter 8.
Chemical Engineering

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
In the scope of the master’s dissertation, this current project was developed during a curricular internship at MAHLE Engine Components S.A in Murtede where pistons rings (segments) are produced.The main objective of this project it’s focused in developed and implement of improvements in the external brushing process in pistons rings with PVD, ensuring that the final product fulfills the requirements of the costumers. In this case study the initial problem was an excessive material reduction in the external face of the piston ring, in other words, the initial problem is an excessive rounding of the radius of contact face.In the course of this work an evaluation was made of the current situation of the external brushing process for PVD oil rings. A test plan was set up, it was made an analysis of the respective results, as well as the definition of correct parameters to be used in the process and the presentation of proposals for new brushes to be used in the process.In the analysis of test results, it was used the MAHLE metrology laboratory, where all the measurements presented in this work were made.Besides that, the influence of time and brushing pressure for the current process was studied, with the purpose to realize the impact of these parameters in the reduction of material in the external face of the piston ring. After testing brushes, with densities and grain sizes lower than the brush that it´s currently used in the process, it was verified that there is less material removal from the contact face of the ring. It has also been notice that for the flap brush currently used in this process there is more material removal when the brushing pressure is varied than when the brushing time is varied.
No âmbito da realização da dissertação de mestrado, este projeto foi desenvolvido durante um estágio curricular na Mahle Componentes de Motores S.A em Murtede onde são produzidos anéis de pistão (segmentos). O principal objetivo deste trabalho passa por desenvolver e implementar melhorias no processo de escovamento externo em anéis de óleo com PVD, garantindo que o produto final vá de encontro às especificações e necessidades exigidas pelos clientes.Neste caso de estudo o problema inicial trata-se de uma remoção excessiva de material da face de contacto do anel de óleo com PVD, isto é, havia um arredondamento excessivo dos raios da face de trabalho do segmento destinado à terceira canaleta.No decorrer deste trabalho foi feita uma avaliação da situação atual do processo de escovamento externo para anéis de óleo com PVD.Foi definido um plano de testes, levantamento dos respetivos resultados, assim como a definição de parâmetros corretos a usar no processo e apresentação de propostas de novas escovas a utilizar na operação. Para além disso foi estudada a influência do tempo e da pressão de escovamento para o processo atual.No procedimento da análise de resultados dos testes, recorreu-se ao laboratório de metrologia da MAHLE, onde foram efetuadas todas as medições apresentadas neste trabalho.Depois de realizados testes com escovas, de densidades e tamanhos de grão inferiores, comparativamente com a escova usada atualmente no processo, verificou-se que há menor remoção de material da face de contacto do anel.Constatou-se que para a escova flap usada atualmente neste processo, há maior remoção de material quando se faz variar a pressão de escovamento do que quando se faz variar o tempo do escovamento.