Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 95-114).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed July 9, 2007). PDF text: vi, 167 p. : ill. UMI publication number: AAT 3245356. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (doctoral)--University of Helsinki, 2007. / Includes bibliographical references. Also available on the World Wide Web.

Microbiologically Influenced Corrosion (MIC) is a process influenced by microbial presence and their metabolic activities. This study examined the microbial effects on metal corrosion under different environmental conditions with nutrient supplements. Experiments were conducted by inserting stainless steel 304 and mild steel coupons (2.5 x 2.5 cm²) into loam soil and a simulated seawater/sediment system with various nutrient conditions (sterilized, without supplement, 5 mM NaNO₃ or NH₄NO₃). Two mild and stainless steel coupons were removed monthly and the corrosion rate was evaluated based on the weight loss. Bacterial populations were enumerated using the most probable number (MPN) technique. The presence and adhesion of microbes on mild steel coupons were examined using Scanning Electron Microscopy (SEM). The extent of the corrosion process on the surface of the metal coupons were visualized by using the Stereo Microscope. The elemental composition of the corrosion products formed on the coupon surface were determined by Energy Dispersive X-Ray analyses. Isolation and identification of aerobic microorganisms were conducted and examined for its potential in either accelerating or inhibiting corrosion. The bacterial populations present on the mild steel surface were analyzed by fluorescent in situ hybridization. Denaturing gradient gel electrophoresis (DGGE) analyses of PCR-amplified 16S rDNA fragments were conducted to determine the microbial community complexity of the biofilm. Greater weight losses of mild steel in loam soil and the seawater/sediment system with NaNO₃ (48.86 mg/g and 19.96 mg/g of weight loss, respectively after 20 weeks) were observed with total heterotrophic bacterial population presented (106.695 MPN/ml and 0.11187 MPN/ml respectively) compared to the autoclaved control (7.17845 mg/g and 0.12082 mg/g of weight loss respectively). Supplementation of 5 mM NH₄NO₃ increased the total heterotrophic bacterial population and resulted in a decrease in weight loss measurements on the stainless steel coupons (211.4 MPN/ml with a 0.01 mg/g weight loss) after 20 weeks compared to the non-autoclaved loam soil and loam soil supplemented with NaNO₃ (139.2 MPN/ml and 134.9 MPN/ml respectively with no weight loss). SEM images of the mild steel coupons confirmed the presence and adherence of bacteria on the metal surface. Stereo microscopic images displayed reddish-brown deposits and pitting on the coupon surface. Isolation, identification and sequence analysis revealed that most microorganisms were the Bacillus species. This group of microorganisms are iron-oxidizing bacteria that could also promote the corrosion process. After 20 weeks of incubation, the total SRB cell counts were lower in samples supplemented with NaNO₃ in both loam soil and the seawater/sediment system. This study also indicated that the isolated aerobic microorganisms do play a role in the corrosion process in both stainless and mild steel. DGGE analysis revealed microbial diversity in the corrosion products especially those affiliated to the bacterial phyla Firmicutes and Gamma-Proteobacteria. Fluorescent in situ hybridization analysis allowed for an overall estimation of Eubacteria and sulphate-reducing bacteria present in the biofilm formed on the surface of mild steel. The current study indicates that the addition of nitrates did not significantly reduce the rates of corrosion of both mild and stainless steel. However, it does seem that environmental conditions did pose as an important factor in the corrosion process. Therefore, further studies need to be implemented to analyze the environmental type, microbial composition and optimization of the concentration of nitrates for possible mitigation of metal corrosion. To optimize MIC prevention and control, collaboration between engineers and microbiologists proves advantageous to develop an environmentally sound and potentially cost-effective approach to control corrosion. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

CAPES / O presente estudo tem como objetivo avaliar o efeito das dietas: aveia, azevém e suplemento (AVAZS), aveia, azevém e ervilhaca (AVAZE) e aveia, azevém, ervilhaca e suplemento (AVAZES), no consumo de nutrientes, parâmetros ruminais e na síntese de proteína microbiana em bovinos. O experimento foi conduzido na Universidade Tecnológica Federal do Paraná (UTFPR), Câmpus Dois Vizinhos, na Unidade de Ensino e Pesquisa (UNEPE) – Bovinocultura de Corte, durante os meses de junho à dezembro de 2014. O delineamento experimental foi um duplo Quadrado Latino 3 x 3 (3 dietas x 3 períodos), utilizando-se seis bovinos machos castrados, canulados no rúmen, com peso vivo médio de 350 kg. As amostras de forragem foram coletadas pelo método de simulação de pastejo. O consumo dos animais em pastejo foi determinado utilizando óxido de cromo. As coletas de líquido ruminal foram realizadas a cada duas horas no último dia de cada período experimental. As coletas de urina foram realizadas nos últimos cinco dias de cada período. O consumo de carboidratos não fibrosos (CCNF), o consumo de nutrientes digestíveis totais (CNDT), consumo de nitrogênio (CN), a retenção de nitrogênio (RN), a digestibilidade verdadeira do nitrogênio (DVN), a digestibilidade do nitrogênio (DN) e a eficiência de utilização do nitrogênio (EUN) variaram estatisticamente (α<0,05) para os bovinos alimentados com as diferentes dietas. O pH e a amônia foram superiores (α<0,05) para as dietas sem suplemento, já os açucares totais, peptídeos e α- amino foram superiores (α<0,05) no tratamento contento leguminosa e suplemento. O pH, amônia e os açúcares totais variaram cubicamente em relação as horas do dia, já os peptídeos e os α-amino variaram linearmente. Os valores de síntese microbiana não variou significativamente (α>0,05). Bovinos mantidos em pastagens temperadas associadas à leguminosa e recebendo suplementação apresentam maior CCNF e CNDT. Já os bovinos não suplementados apresentam maior CN, melhor RN, maior DN, maior DVN e melhor EUN. Animais em pastejo exclusivo apresentam pH e amônia ruminal mais elevados, já bovinos recebendo suplementação e em consórcio com ervilhaca possuem teores de açúcares totais, peptídeos e α-amino superior as demais dietas. / This study aims to evaluate the effect of diets: oats, ryegrass and supplement (AVAZS), oats, rye and vetch (AVAZE) and oats, ryegrass, vetch and supplement (AVAZES), consumption of nutrients, ruminal parameters and microbial protein synthesis in cattle. The experiment was conducted at the Universidade Tecnológica Federal do Paraná (UTFPR), Câmpus Dois Vizinhos, the Unit of Education and Research (UNEPE) - Cattle Court, during the months of June to December 2014. The experimental design was a double Latin square 3 x 3 (3 diets x 3 times), using six cattle steers, cannulated in the rumen, with average live weight of 350 kg. The forage samples were collected by the grazing simulation method. The consumption of grazing animals was determined using chromium oxide. The samples of rumen fluid were taken every two hours on the last day of each experimental period. Urine samples were taken in the last five days of each period. The consumption of non-fibrous carbohydrates (CCNF), the total digestible nutrients (CNDT), nitrogen consumption (CN), nitrogen retention (RN), the true digestibility of nitrogen (DVN), the digestibility of nitrogen (DN ) and nitrogen use efficiency (NUE) varied statistically (α <0.05) for cattle fed different diets. The pH and ammonia were higher (α<0.05) for the diets without supplement, since total sugars, peptides and α-amino were higher (α <0.05) in treatment satisfaction and legume supplement. The pH, ammonia and total sugars varied cubically regarding hours of the day, as the peptides and α-amino varied linearly. The values of microbial synthesis did not differ significantly (α> 0.05). Cattle kept in temperate grasslands associated with legumes and receiving supplementation have higher CCNF and CNDT. The non-supplemented cattle have higher CN, RN best, most DN greater DVN and better EUN. Animals exclusively grazing have pH and higher ruminal ammonia, since cattle receiving supplementation and intercropping with vetch have levels of total sugars, peptides and α-amino superior to other diets.