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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Remoção de matéria orgânica, nitrogênio e fósforo em esgoto diluído com reatores em bateladas sequenciais

SANTOS NETO, Antonio Gustavo dos 01 August 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-12-05T14:40:13Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação ANTONIO GUSTAVO BIBLIOTECA - versão final.pdf: 1726777 bytes, checksum: 84cfc9b69cd2e68ee079cffc86278903 (MD5) / Made available in DSpace on 2017-12-05T14:40:13Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação ANTONIO GUSTAVO BIBLIOTECA - versão final.pdf: 1726777 bytes, checksum: 84cfc9b69cd2e68ee079cffc86278903 (MD5) Previous issue date: 2016-08-01 / CAPES / Matéria orgânica e nutrientes são poluentes presentes nos esgotos sanitários que, quando não tratados e lançados nos corpos receptores, causam problemas ambientais como a depleção de oxigênio dissolvido, a perda da biodiversidade e aceleração do processo de eutrofização. A remoção de nutrientes dos esgotos apesar de ser uma questão resolvida nos países desenvolvidos ainda é um desafio para o Brasil. No presente trabalho foram operados dois reatores biológicos em escala piloto sob o regime de bateladas sequências (RBS). Na fase de reação, os reatores eram submetidos a condições anaeróbias, aeróbias e anóxicas, onde, um dos reatores na fase aeróbia, operava em regime de aeração contínua (RC) e o outro sob regime de aeração intermitente (RI). O afluente utilizado no sistema era proveniente do tratamento preliminar de uma estação de tratamento de esgotos e apresentou características de esgoto diluído (304 mgDQO.L-1). A carga orgânica média aplicada ao sistema foi de 63,8 g.DQO-1.d-1 e relação DQO:P de 108,5. O principal ácido graxo volátil presente no afluente foi o ácido acético (numa concentração média de 38,5 mg.L-1). A remoção de matéria orgânica (avaliada em termos de DQO) e de fósforo, através da remoção biológica avançada de fósforo (EBPR) foram satisfatórias para os dois sistemas com remoções acima de 80%, chegando a concentrações abaixo de 10 mgDQO.L-1 e 0,1 mgP.L-1, já a remoção de nitrogênio só se manteve estável no reator de aeração contínua, onde foi alcançada uma remoção de 97% para nitrogênio amoniacal e de 63% para nitrogênio total. / Organic matter and nutrients are pollutants presented in domestic wastewater, when not treated and released into receiving water bodies may cause environmental problems such as depletion of dissolved oxygen, biodiversity loss and acceleration in the eutrophication process. Despite the removal of nutrients be successfully made in developed countries, it is still a challenge in Brazil. In this study, two biological reactors in pilot scale were operated under regime of batch sequence. In the reaction phase, the reactors were carried out in anaerobic, aerobic and anoxic conditions. One of the reactors in aerobic phase was operated under continuous aeration mode (RC) and the other under intermittent aeration system (RI). The influent used in this study underwent preliminary treatment in a wastewater treatment plant and presented diluted sewage characteristics (304 mgDQO.L-1). The average organic load applied to the system was 63.8 gDQO-1d-1 and ratio COD / P 108.5. The main volatile fatty acid present in the influent was acetic acid (an average concentration of 38.5 mg. L-1). The removal of organic matter (measured in terms of COD) and phosphorus, trough of Enhanced Biological Phosphorus Removal (EBPR) were satisfactory for both systems with over 80% removal, reaching concentrations below 10 mgDQO.L-1-one and 0.1 mgP.L-1. In addition, the nitrogen removal remained stable only under continuous aeration reactor in which 97% of ammonia nitrogen and 63% of total nitrogen.
42

Aspectos microbiológicos do tratamento de esgotos sanitários em reatores em batelada sequencial com lodo granular

ALVES, Oucilane Ingret Moreno 17 February 2017 (has links)
Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2018-03-13T18:54:02Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Oucilane - versão final da dissertação.pdf: 2341797 bytes, checksum: 8a8683e7a09cf5b3b53d182aeb69a96c (MD5) / Made available in DSpace on 2018-03-13T18:54:02Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Oucilane - versão final da dissertação.pdf: 2341797 bytes, checksum: 8a8683e7a09cf5b3b53d182aeb69a96c (MD5) Previous issue date: 2017-02-17 / FACEPE / O tratamento com grânulos aeróbios apresentam inúmeras vantagens em relação ao sistema de lodos ativados convencionais. Esta tecnologia, quando operada sob condições específicas, é capaz de realizar em uma única unidade a remoção de matéria orgânica e nutrientes, necessitando, assim, de menores áreas de implantação. Os micro-organismos presentes na estrutura do grânulo são semelhantes ao sistema de lodos ativados. Entretanto, os grânulos possuem em sua estrutura microzonas aeróbias, anóxicas e anaeróbias onde os processos de remoção ocorrem simultaneamente. Contudo, a maioria dos estudos desenvolvidos tem utilizado esgoto sintético e escala laboratorial. Neste trabalho, o objetivo foi estudar a influência de diferentes trocas volumétricas e velocidades ascensionais na formação de grânulos aeróbios e na diversidade microbiana em reatores em bateladas sequenciais tratando esgoto doméstico diluído. Para isso, foram realizados três experimentos, E1, E2 e E3 com diferentes trocas volumétricas (59%, 71% e 59%, respectivamente) e diferentes velocidades ascensionais (1,06 cm.s-1, 0,88 cm.s-1 e 0,88 cm.s-1, respectivamente), tempo final de sedimentação de 10 minutos e tempo de ciclo de 3 horas. Grânulos foram observados nos experimentos aos 51 dias, 78 dias e 53 dias para E1, E2 e E3, respectivamente. Avaliando a influência da presença e ausência de inóculo, quando operados com a mesma troca volumétrica, no tempo necessário à granulação e na concentração média de SSVLM, identificou-se que não houve diferença entre E1 e E3. A eficiência de remoção de DQO e NH4+-N obtida no E1 foi de 81,2 ± 7,8% e 62,6 ± 30,1%, respectivamente; no E2, de 81,3 ± 6,5% e 42,2 ± 19,6%, respectivamente; e, no E3, de 78,3 ± 9,8% e 75,4 ± 25,4%. O processo de nitrificação foi afetado principalmente pela troca volumétrica, devido à lavagem da biomassa de crescimento lento para fora dos reatores. Os testes respirométricos indicaram que houve uma maior concentração de micro-organismos heterotróficos no sistema. Avaliando a comunidade microbiana presente na estrutura dos grânulos, pôde-se observar a predominância da associação de vorticellas e rotíferos na superfície dos grânulos. Aplicando a técnica da PCR observou-se que no processo de nitrificação e desnitrificação, os grupos de bactérias dominantes foram as BOA e as desnitrificantes. A presença identificada do grupo Anammox e desnitrificantes na fase de grânulos nos reatores indicaram a presença de microzonas anóxicas. E, por fim, apesar da presença de PAO nos sistemas, não houve uma alta eficiência de remoção de fósforo. Isso ocorreu devido à não estabilização do sistema e ausência de grânulos bem desenvolvidos com presença de microzonas anaeróbias. / The treatment with aerobic granules has many advantages over the conventional activated sludge system. This technology, when operated under specific conditions, is capable of carrying out in a single unit the removal of organic matter and nutrients, thus requiring smaller areas of implantation. The microorganisms present in the granule structure are similar to the activated sludge system. However, granules have aerobic, anoxic and anaerobic microzones in their structure where removal processes occur simultaneously. However, most studies have used synthetic sewage and laboratory scale. In this work, the objective was to study the influence of different volumetric exchanges and ascending speeds in the formation of aerobic granules and microbial diversity in sequential batch reactors treating dilute domestic sewage. For this, three experiments were held, E1, E2 and E3 with different volumetric exchanges (59%, 71% and 59%, respectively) and different ascending speeds (1.06 cm.s-1, 0.88 cm.s-1 and 0.88 cm.s-1, respectively), final sedimentation time of 10 minutes and cycle time of 3 hours. Granules were observed in the experiments at 51 days, 78 days and 53 days for E1, E2 and E3, respectively. Evaluating the influence of presence and absence of inoculum, when operated with the same volumetric exchange, in the time required for the granulation and in the mean concentration of SSVLM, it was identified that there was no difference between E1 and E3. The removal efficiency of COD and NH4 + -N obtained in E1 was 81.2 ± 7.8% and 62.6 ± 30.1%, respectively; In E2, of 81.3 ± 6.5% and 42.2 ± 19.6%, respectively; and, at E3, 78.3 ± 9.8% and 75.4 ± 25.4%. The nitrification process was mainly affected by the volumetric exchange due to the slow-growing biomass washing out of the reactors. The respirometric tests indicated that a higher concentration of heterotrophic microorganisms in the system. As to microbial community present in the structure of the granules, the was a predominance of association of vorticellas and rotifers. The PCR technique was applied to identify that in the process of nitrification and denitrification, the dominant bacteria groups were AOB and denitrifiers. The identified presence of the Anammox group and denitrifiers in the granule phase in the reactors indicated the presence of anoxic microzones. Finally, despite the presence of PAOs in the systems, there was no high phosphorus removal efficiency. This occurred due to the non-stabilization of the system and the absence of well-developed granules with the presence of anaerobic microzones.
43

Oberflächenmodifikation von Si(001) mittels Se

Kutzer, Martin 21 October 2005 (has links)
Im Rahmen dieser Diplomarbeit wurden Si(001)-Oberflächen mit Selen modifiziert und anschließend charakterisiert. Die Herstellung der Selenpassivierungsschichten wurde in einer MBE-Anlage durchgeführt. Die Charakterisierung erfolgte durch RHEED-, LEED- und RBS-Untersuchungen.
44

Simultaneous Quantification and Visualization of Titanium Dioxide Nanomaterial Uptake at the Single Cell Level in an In Vitro Model of the Human Small Intestine

Meyer, Thomas, Venus, Tom, Sieg, Holger, Böhmert, Linda, Kunz, Birgitta M., Krause, Benjamin, Jalili, Pegah, Hogeveen, Kevin, Chevance, Soizic, Gauffre, Fabienne, Burel, Agnes, Jungnickel, Harald, Tentschert, Jutta, Laux, Peter, Luch, Andreas, Braeuning, Albert, Lampen, Alfonso, Fessard, Valerie, Meijer, Jan, Estrela-Lopis, Irina 12 May 2020 (has links)
Useful properties render titanium dioxide nanomaterials (NMs) to be one of the most commonly used NMs worldwide. TiO2 powder is used as food additives (E171), which may contain up to 36% nanoparticles. Consequently, humans could be exposed to comparatively high amounts of NMs that may induce adverse effects of chronic exposure conditions. Visualization and quantification of cellular NM uptake as well as their interactions with biomolecules within cells are key issues regarding risk assessment. Advanced quantitative imaging tools for NM detection within biological environments are therefore required. A combination of the label-free spatially resolved dosimetric tools, microresolved particle induced X-ray emission and Rutherford backscattering, together with high resolution imaging techniques, such as time-of-flight secondary ion mass spectrometry and transmission electron microscopy, are applied to visualize the cellular translocation pattern of TiO2 NMs and to quantify the NM-load, cellular major, and trace elements in differentiated Caco-2 cells as a function of their surface properties at the single cell level. Internalized NMs are not only able to impair the cellular homeostasis by themselves, but also to induce an intracellular redistribution of metabolically relevant elements such as phosphorus, sulfur, iron, and copper.
45

Improved handling of a sample holder goniometer at Uppsala University’s Tandem Laboratory

WU-VIGNOLO, Alexander January 2020 (has links)
Rutherford backscattering spectrometry are performed at the Tandem Laboratory of Uppsala Univer-sity, providing information on thickness and composition of materials. To avoid the channelling effect,a wiggling routine has been created to randomly move the sample holding goniometer during the spec-trum acquisition. The aim of this project is to incorporate this routine into the batch measurement infrastructure.
46

Phenomenology of Restricted Repetitive Behavior in Children with Autism Spectrum Disorders: Association with Demographic and Clinical Features

Novak, Laura Elizabeth, Novak January 2018 (has links)
No description available.
47

Synthesis, Modification, and Analysis of Silicate Cosmic Dust Analogues Using Ion-Beam Techniques

Young, Joshua Michael 08 1900 (has links)
Silicates analogous to cosmic dust were synthesized, modified, and analyzed utilizing ion-beam techniques with Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD). Silicate dust is a common constituent in interstellar space, with an estimated 50% of dust produced in the stellar winds of M class Asymptotic Giant Branch (AGB) stars. Silicate dust acts as a surface upon which other chemicals may form (water ice for example), increasing significance in the cosmochemistry field, as well as laboratory astrophysics. Silicate formation in the stellar winds of AGB stars was simulated in the laboratory environment. Three sequential ion implantations of Fe-, MgH2-, and O- with thermal annealing were used to synthesize a mixture appropriate to silicate dust in the surface layers of a p-type Si substrate. Post implantation He+ irradiation was shown to preferentially induce crystalline formation in the analogue prior to thermal annealing. This effect is believed to originate in the ion-electron interaction in the Si substrate. The effects of ionization and ion energy loss due to electronic stopping forces is believed to precipitate nucleation in the amorphous media. For annealing temperatures of 1273 K, predominant quartz formation was found in the substrate, whereas lower annealing temperatures of 1000 K formed enstatite without post-implantation He+ irradiation, and olivine with He+ irradiation. Post annealed crystalline phase modification was investigated via x-ray diffraction and elemental compositions were investigated utilizing RBS. Finally, the interdiffusion of Fe and Mg at temperatures of 900-1100 K was investigated with RBS, and activation energies for interdiffusion were extracted for the transition from amorphous to crystalline phase in the silicate analogues. Fe had an interdiffusion energy of 1.8 eV and Mg 1.5eV. The produced analogues have similar properties to those inferred from infrared spectroscopy of the stellar winds of M-class AGB stars with an oxygen-rich outflow. This work established a method of silicate production using ion beam modifications, explored He+ irradiation effects in the annealed structures, and derived interdiffusion activation energies for Fe and Mg in the amorphous structure. Grain sizes were <100 nm with the observed formation of quartz, enstatite, and olivine.
48

A Study on the Behavior of Deep, Slender Wide Flange Steel Beam-Column Members in Seismic Applications

Pettersson, Frida 28 June 2016 (has links)
No description available.
49

Modificações superficiais em polímeros por feixes iônicos para estudo de biocompatibilidade / Surface modifications in polymers by ion beams for the study of biocompatibility

Trindade, Gustavo Ferraz 07 October 2013 (has links)
Nos dias atuais, grande parte das intervenções cirúrgicas inclui o implante de materiais. Os grandes obstáculos na implantação de próteses em organismos humanos são a coagulação sanguínea em contato com o material devido ao alto grau de ativação plaquetária e a compatibilidade dos tecidos biológicos ao material implantado. Agregando melhorias de propriedades mecânicas a superfícies biocompatíveis, materiais poliméricos apresentam grandes tendências a serem excelentes candidatos a biomateriais para tais aplicações. O objetivo deste trabalho foi realizar modificações superficiais em polímeros através do método de implantação por feixe iônico a fim de se investigar mudanças induzidas em suas propriedades superficiais e estudar possíveis mudanças em sua biocompatibilidade, em específico, sua hemocompatibilidade. Amostras de policarbonato foram irradiadas com feixes de íons de argônio com energia 23 keV e cinco diferentes doses. As superfícies das amostras foram analisadas com medidas de ângulo de contato, microscopia de força atômica, espectroscopia de massa de íons secundários, espectroscopia de fotoelétrons, espectroscopia de retroespalhamento Rutherford, deteção de recuo elástico, espectroscopia de raios-X induzidos por partículas e testes de adesão plaquetária. Os resultados das diferentes técnicas apontaram de forma consistente a uma série de alterações químicas e físicas induzidas nas superfícies das amostras, dentre elas: a perda significativa de hidrogênio nas amostras irradiadas, aumento do grau de reticulação entre as cadeias poliméricas que levou ao aumento de elétron deslocalizados e mudança de coloração, remoção de aditivos, migração à superfície de átomos de argônio implantados e alteração de hidrofilicidade. Ao confrontar todos os resultados obtidos com os resultados dos testes de adesão plaquetária, constatou-se que os efeitos observados aumentam o caráter trombogênico da superfície do policarbonato e que a remoção de aditivos com grupos sulfato e sulfonato após irradiação com argônio teve grande influência em tal aumento. / In the current days, a big part of the surgical interventions includes the implant of materials. The great obstacles for prosthesis implantation in living organisms are the blood clotting when in contact to the material due to a high level of platelet activation and the biological tissues compatibility to the implanted material. By joining improvements on mechanical properties to biocompatible surfaces, polymer materials present high tendencies to be excellent biomaterials candidates for such applications. The objective of this work was to perform surface modification in polymers through the ion beam implantation method in order to investigate changes induced in their surface properties and study possible biocompatibility changes. Samples of polycarbonate were irradiated with argon ion beam with 23 keV energy and different doses. The surfaces of the samples were analyzed by contact angle measurements, atomic force microscopy, secondary ion mass spectroscopy, x-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, elastic recoil detection, particle induced x-ray spectroscopy and platelet adhesion tests. The results from the different techniques pointed consistently to a series of chemical and physical changes induced on the samples\' surfaces, such as: significant loss of hydrogen for the irradiated samples, increase of cross-linking between polymer chains which led to the increase of delocalized electrons and color change, removal of additives, migration of argon atoms to the surface and hydrophilicity changes. By comparing all the obtained results to the platelet adhesion tests results, it was found that the observed effects increase the thrombogenic characteristic of the polycarbonate surface and that the removal of additives with sulfate and sulfonate groups after the argon irradiation had great influence on such increase.
50

Modificações superficiais em polímeros por feixes iônicos para estudo de biocompatibilidade / Surface modifications in polymers by ion beams for the study of biocompatibility

Gustavo Ferraz Trindade 07 October 2013 (has links)
Nos dias atuais, grande parte das intervenções cirúrgicas inclui o implante de materiais. Os grandes obstáculos na implantação de próteses em organismos humanos são a coagulação sanguínea em contato com o material devido ao alto grau de ativação plaquetária e a compatibilidade dos tecidos biológicos ao material implantado. Agregando melhorias de propriedades mecânicas a superfícies biocompatíveis, materiais poliméricos apresentam grandes tendências a serem excelentes candidatos a biomateriais para tais aplicações. O objetivo deste trabalho foi realizar modificações superficiais em polímeros através do método de implantação por feixe iônico a fim de se investigar mudanças induzidas em suas propriedades superficiais e estudar possíveis mudanças em sua biocompatibilidade, em específico, sua hemocompatibilidade. Amostras de policarbonato foram irradiadas com feixes de íons de argônio com energia 23 keV e cinco diferentes doses. As superfícies das amostras foram analisadas com medidas de ângulo de contato, microscopia de força atômica, espectroscopia de massa de íons secundários, espectroscopia de fotoelétrons, espectroscopia de retroespalhamento Rutherford, deteção de recuo elástico, espectroscopia de raios-X induzidos por partículas e testes de adesão plaquetária. Os resultados das diferentes técnicas apontaram de forma consistente a uma série de alterações químicas e físicas induzidas nas superfícies das amostras, dentre elas: a perda significativa de hidrogênio nas amostras irradiadas, aumento do grau de reticulação entre as cadeias poliméricas que levou ao aumento de elétron deslocalizados e mudança de coloração, remoção de aditivos, migração à superfície de átomos de argônio implantados e alteração de hidrofilicidade. Ao confrontar todos os resultados obtidos com os resultados dos testes de adesão plaquetária, constatou-se que os efeitos observados aumentam o caráter trombogênico da superfície do policarbonato e que a remoção de aditivos com grupos sulfato e sulfonato após irradiação com argônio teve grande influência em tal aumento. / In the current days, a big part of the surgical interventions includes the implant of materials. The great obstacles for prosthesis implantation in living organisms are the blood clotting when in contact to the material due to a high level of platelet activation and the biological tissues compatibility to the implanted material. By joining improvements on mechanical properties to biocompatible surfaces, polymer materials present high tendencies to be excellent biomaterials candidates for such applications. The objective of this work was to perform surface modification in polymers through the ion beam implantation method in order to investigate changes induced in their surface properties and study possible biocompatibility changes. Samples of polycarbonate were irradiated with argon ion beam with 23 keV energy and different doses. The surfaces of the samples were analyzed by contact angle measurements, atomic force microscopy, secondary ion mass spectroscopy, x-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, elastic recoil detection, particle induced x-ray spectroscopy and platelet adhesion tests. The results from the different techniques pointed consistently to a series of chemical and physical changes induced on the samples\' surfaces, such as: significant loss of hydrogen for the irradiated samples, increase of cross-linking between polymer chains which led to the increase of delocalized electrons and color change, removal of additives, migration of argon atoms to the surface and hydrophilicity changes. By comparing all the obtained results to the platelet adhesion tests results, it was found that the observed effects increase the thrombogenic characteristic of the polycarbonate surface and that the removal of additives with sulfate and sulfonate groups after the argon irradiation had great influence on such increase.

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