Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 4 uppsatser.

Thesis (M.Sc.(Chemical Engineering))--University of Pretoria, 2007. / Abstract in English. Includes bibliographical references (leaves 74-80).

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 12, 2008) Includes bibliographical references.

Thesis (PH.D.)--Michigan State University. Chemistry, 2008. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references. Also issued in print.

Tougher environmental legislations are a driving force for development of aftertreatment technologies for truck and car exhaust gases. In particular, the emission requirements are high on nitrogen oxides (NOx) and particulate matter. Focus of this thesis work is to develop a component in the exhaust system, a NOx level reduction system. The currently used technology with urea evaporator has problem with formation of urea crystals due to delayed urea evaporation. Crystalline urea causes reduced exhaust flow and thus build up a pressure in the system that has negative impact on the performance of the engine. Feasibility study was done to understand function, advantage and disadvantages of current design and the need for a new design. The main task of this project was to investigate and propose a new design of the helix-rotary evaporator and to present it in the form of parametric model. Material selection needed for urea injection arrangement, 3D printed model for visualization of the concept and integration of the model to next generation aftertreatment system (NGA) are examples of sub-tasks that was performed to reach the main objective. Several generations of selected concept were developed in 3D design which later was 3D printed to visualize the ideas. The parametric 3D model was designed so that it later serves as input model for a later phase in the development project, where computational fluid dynamics is utilized. Parametric modelling is used to provide wide range of possibility to generate different models for simulation and reduce pre-simulation works. Selected concept parametric model has six different parameters that can be analysed. Material selection carried out to injection manifold thought CES Edupack and consultancy of material engineers. Three different austenitic stainless steels were recommended.

The study was made at Lubigi sewage treatment plant in Kampala, Uganda, during February and March 2018. The aim of this master thesis was to treat faecal sludge with two different methods, urea and lime, to investigate the efficiency of the chemicals to inactivate pathogens and to estimate the feasibility and the costs of the treatment. The chemical treatments were performed on sludge of two different moisture contents. The results from the treated sludge were compared with an untreated drying bed filled at the start of the study period to use as a control. The investigated pathogens were E. coli, bacteriophages and Ascaris eggs. The total solids and volatile solids were analysed, and the pH was measured. The results of the study including a calculation of costs were used to assess the feasibility of these treatment methods at Lubigi sewage treatment plant. The results show that the treatment using lime and urea reduces the level of active pathogens in the faecal sludge. The drying process in the beds at the treatment plant also decreases the level of detected pathogens in the sludge, but not to the same extent as when adding chemicals. The E. coli in the treated sludge were under the detection limit before the study period was done. Ascaris eggs were still detected in the sludge by the final sampling occasion. Further monitoring of the treated sludge might show an additional decrease of Ascaris since the time of storage after treatment enables pathogen die-off. The bacteriophages analyses only succeeded for two sampling occasions, although a decrease of detected phages is visible in the results. Again, the time of storage is significant for pathogen reduction, which is why a decrease of bacteriophages is expected if the sludge were to be further monitored. The feasibility of the two treatment methods is mainly restricted by costs. Lime treatment is approximately seven times more expensive than urea treatment and is also required in a larger amount to treat the sludge. On the other hand, using lime to treat faecal sludge is a proven and effective method. Further studies would improve the knowledge of the sludge characteristics at Lubigi and help determine the most preferable treatment for the sludge to protect the environment and public health. For example, by focusing on one treatment method, more detailed information can be gathered, and if performing a study in a larger scale, the representativeness would increase. To make sure there is no risk of spreading pathogens to the environment, further analyses should be carried out directly before selling the sludge to farmers.

Made available in DSpace on 2015-10-06T13:03:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-30. Added 1 bitstream(s) on 2015-10-06T13:18:41Z : No. of bitstreams: 1 000849738.pdf: 569843 bytes, checksum: 1e0c956302526d7e014876a325301df6 (MD5) / A escória de siderurgia surgiu na agricultura como fonte alternativa de material corretivo da acidez do solo, trazendo em sua composição o silício, considerado um elemento benéfico para as plantas. O objetivo do presente trabalho foi avaliar o efeito da aplicação de nitrogênio em cobertura associado ao uso da escória de siderurgia e calcário sobre as propriedades químicas do solo, o estado nutricional, o acúmulo de N e Si nas folhas e colmos, a produção de colmos e a qualidade tecnológica da terceira soqueira de cana-de-açúcar. O experimento foi desenvolvido em sistema de colheita sem despalha a fogo em um Latossolo Vermelho distrófico, textura média. O delineamento foi de blocos ao acaso, com tratamentos dispostos em esquema fatorial 5x2, cinco doses de nitrogênio (0; 40; 80; 120 e 160 kg ha-1) e dois materiais corretivos, escória de siderurgia 0,9 t ha-1 e calcário 1,0 t ha-1, com quatro repetições. Foram avaliados os atributos químicos do solo, o desenvolvimento, o estado nutricional, a produção de matéria seca, a produção de colmos e a qualidade tecnológica da cana-de-açúcar. Aplicação dos corretivos afetou os teores de H+Al e a saturação por bases aos 12 meses. Houve interações dos corretivos, doses de N e profundidades aos 6 e 12 meses. Os tratamentos não afetaram o estado nutricional e o desenvolvimento da cultura, apesar de interação para acúmulo de matéria seca nas folhas. As doses de nitrogênio, independentemente do corretivo aplicado, não afetaram a produção de colmos e a qualidade tecnológica da cana-de-açúcar / The slag appeared in agriculture as an alternative source of corrective material soil acidity, bringing in its composition silicon, considered a beneficial element for plants. The objective of this study was to evaluate the effect of nitrogen application in coverage associated with the use of slag and limestone on the chemical properties of the soil, nutritional status, the accumulation of N and Si in the leaves and stems, producing stems and the technological quality of the third ratoon of sugarcane. The experiment was carried on without fire husking harvesting system in an Oxisol, medium texture. The design was a randomized block, with treatments arranged in a 5x2 factorial scheme, five nitrogen rates (0, 40, 80, 120 and 160 kg ha- 1) and two corrective materials, slag 0,9 t ha-1 and limestone 1,0 t ha-1, with four replications. They evaluated the soil chemical properties, development, nutritional status, the production of dry matter production of stems and the technological quality of sugarcane. Liming affected the H+Al contents and base saturation at 12 months. There were interactions corrective, N rates and depths at 6 and 12 months. The treatments did not affect the nutritional status and the development of culture, although interaction for dry matter accumulation in the leaves. Nitrogen rates, regardless of the correction did not affect the production of stems and the technological quality of sugarcane

Made available in DSpace on 2014-06-11T19:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-01Bitstream added on 2014-06-13T20:16:26Z : No. of bitstreams: 1 delbem_fc_me_araca.pdf: 413934 bytes, checksum: 54368953c1828d11391dee67578da4fa (MD5) / Universidade Estadual Paulista (UNESP) / No Brasil, as pastagens têm sido a forma mais utilizada para a alimentação de bovinos. Ao longo dos primeiros anos perdem seu potencial produtivo e vigor da rebrota, frequentemente associada à falta de adubação nitrogenada. O objetivo desse trabalho foi verificar o efeito de fontes e doses de adubação nitrogenada, em profundidades, sobre a atividade microbiana, a colonização micorrízica e a fertilidade de solo em uma área de Brachiaria brizantha (Hochst) Stapf cv. Xaraés. O delineamento experimental em blocos casualizados e os tratamentos em esquema fatorial 3 x 4, envolvendo três fontes de nitrogênio (uréia, sulfato de amônio e ajifer-L40), quatro doses de nitrogênio (0, 100, 200 e 400 kg ha-1) estudadas em duas profundidades (0- 0,10 e 0,10-0,20 m), com três repetições. Por parcela, as amostras compostas, por 5 amostras simples de solo, foram coletadas, peneiradas, homogeneizadas e destinadas às análises. A aplicação crescente de doses de N proporcionou redução para os valores de pH no solo, culminando com a percolação do K+ e Mg2+ para as camadas mais profundas do solo e elevando os valores para H+AL e Al3+. O uso do sulfato de amônio em doses elevadas provocou redução aos valores de carbono da biomassa microbiana e quociente microbiano e elevação para quociente metabólico, caracterizando uma atividade microbiana ineficiente. A aplicação de N não alterou significativamente a colonização de fungos micorrízicos arbusculares. No entanto, a esporulação se elevou com relação às doses aplicadas. A produção de massa seca da parte aérea foi maior com o ajifer e da uréia, reduzindo em elevadas doses de N. / Pastures have been the most common method of feeding bovines in Brazil. Throughout the first years these pastures lose their yield potential and regrowth energy. The objective of this study was to verify the effect of sources and doses of nitrogen fertilization, concerning the depths, under microbial activity, percentage of mycorrhizal colonization and soil fertility when covered by Brachiaria brizantha (Hochst) Stapf cv. Xaraés. The randomized blocks design was used and the treatments were under a 3 x 4 factorial scheme, regarding three nitrogen sources (urea, ammonium sulphate, and ajifer-L40) and 4 nitrogen levels (0, 100, 200 and 400 kg ha-1), studied at 2 different depths (0- 0.10 and 0.10-0.20 m), with 3 replications. In each plot, the soil samples, composed with 5 simple samples, were collected, sieved, homogenized and sent to be analyzed. The increasing doses of N employed caused a decrease oh the pH levels in soil with the percolation of K+ and Mg2+ to the deepest layers in soil, increasing the levels of H+Al and Al3+. The usage of ammonium sulfate in high dosages caused a decrease in levels of carbon microbial biomass and an increase in the metabolic quotient, caracterizing an ineffective microbial activity. The employment of N did not meaningfully disturb the fungi mycorrhizal arbusculares colonization. However, these was an increase on the sporulation in relation to the employed dosages. The production of dry matter proved to be grater with ajifer and urea and smaller in high dosage of N.