This thesis introduces functional nanomaterials including superatoms and carbon nanotubes (CNTs) for new layered solids and molecular devices. Chapters 1-3 present how we incorporate superatoms into two-dimensional (2D) materials. Chapter 1 describes a new and simple approach to dope transition metal dichalcogenides (TMDCs) using the superatom Co6Se8(PEt3)6 as the electron dopant. Doping is an effective method to modulate the electrical properties of materials, and we demonstrate an electron-rich cluster can be used as a tunable and controllable surface dopant for semiconducting TMDCs via charge transfer. As a demonstration of the concept, we make a p-n junction by patterning on specific areas of TMDC films. Chapter 2 and Chapter 3 introduce new 2D materials by molecular design of superatoms. Traditional atomic van der Waals materials such as graphene, hexagonal boron-nitride, and TMDCs have received widespread attention due to the wealth of unusual physical and chemical behaviors that arise when charges, spins, and vibrations are confined to a plane. Though not as widespread as their atomic counterparts, molecule-based layered solids offer significant benefits; their structural flexibility will enable the development of materials with tunable properties. Chapter 2 describes a layered van der Waals solid self-assembled from a structure-directing building block and C60 fullerene. The resulting crystalline solid contains a corrugated monolayer of neutral fullerenes and can be mechanically exfoliated. Chapter 3 describes a new method to functionalize electroactive superatoms with groups that can direct their assembly into covalent and non-covalent multi-dimensional frameworks. We synthesized Co6Se8[PEt2(4-C6H4COOH)]6 and found that it forms two types of crystalline assemblies with Zn(NO3)2, one is a three-dimensional solid and the other consists of stacked layers of two-dimensional sheets. The dimensionality is controlled by subtle changes in reaction conditions. CNT-based field-effect transistor (FETs), in which a single molecule spans an oxidatively cut gap in the CNT, provide a versatile, ground-state platform with well-defined electrical contacts. For statistical studies of a variety of small molecule bridges, Chapter 4 presents a novel fabrication method to produce hundreds of FETs on one single carbon nanotube. A large number of devices allows us to study the stability and uniformity of CNT FET properties. Moreover, the new platform also enables a quantitative analysis of molecular devices. In particular, we used CNT FETs for studying DNA-mediated charge transport. DNA conductance was measured by connecting DNA molecules of varying lengths to lithographically cut CNT FETs.

Multilayered materials and structures are of special interest to both academic researchers and industrial engineers as they have been used in an increasing number of applications, such as micro- electromechanical system (MEMS) on polymer substrate, protective coating on metal structure for anti-corrosion, ceramic coating on metal substrate for abrasion resistance, thermal barrier coatings, metal or metal oxide coating on metal-coated polymer for reflectance tuning and protection, as well as laminated composites and structures, etc. However, the surface layer and joint interface are commonly prone to premature failures because of cracking and delamination due to their different thermal and mechanical properties. In return, the premature failures will affect the performance and structural integrity of the device and eventually cause the failure of the multilayered structures to perform their functions. Therefore, it is essential to understand the mechanical behavior and corresponding failure mechanisms of the multilayered systems. This Ph.D. dissertation focuses on the study of opening-mode fracture (OMF) behavior and interfacial delamination in different types of multilayered structures, such as the aluminum plate or wire with alumina protective coating, multilayered advanced polymeric reflectors, and asphalt pavements. In addition, another failure mechanism, i.e. the material degradation and aging, is also studied. Firstly, a two-dimensional (2D) elasoplastic fracture model in Cartesian coordinates is developed to study the OMF in the thin alumina film fully bonded to an aluminum plate undergoing large- scale yielding. The stress field in the coating layer is described by one section between two adjacent cracks. The 2D plane strain formulations are employed to analyze the elastic field in the thin film, while a one-dimensional (1D) linear hardening plastic model is applied to account for the large plastic deformations in the substrate under substantial yielding. An elastoplastic shear lag model is established to transfer the tensile stress in the substrate to the thin film. General formulations and explicit expressions of the elastic/elastoplastic solutions of the thin film/substrate system under different loading stages have been presented. The elastic field in the thin film is then verified with the finite element (FE) results. The fracture energy release rate (ERR) is calculated and corresponding elastoplastic fracture analysis is conducted. Experimental characterization is further conducted to validate the present model; the results show that this fracture modle can capture the fracture initiation, infilling, and saturation in the thin film successfully. This model has been extended to cylindrical coordinates, where the alumina coating is fully bonded to an aluminum wire/rod. Due to the axial symmetry, the proposed 2D elasoplastic fracture model has been reproduced in polar coordinates and be used to study the OMF behavior of alumina coating fully bonded to an aluminum wire. For the case where thermal loading is applied on coating/substrate structures, neither the plane strain nor plane stress assumption can be applied because the thermal loading would introduce multi axial normal stress, therefore, a three-dimensional (3D) elastic fracture model is then developed to study the OMF in the coating fully bonded to the elastic substrate. When the temperature change reaches a certain level, block cracking will initiate in the surface layer to release the accumulated thermal stress. For simplicity, we assume the top surface of the coating would keep flat and in a rectangular shape after deformation. Then the elastic field in both coating and substrate is analyzed and verified with the FE results. The fracture ERR is then obtained based on the solved elastic field and used to analyze the fracture initiation, infilling, and saturation. In order to verify the fracture analysis, the theoretical fracture analysis results are compared with FE simulation results based on the cohesive zone model (CZM) and experimental data from the literature. The good agreement demonstrates the accuracy of the proposed 3D fracture model. In addition, this model for coating/substrate system is extended to study multilayered structures with arbitrary number of layers. In order to verify this extended model, the predicted elastic field in an advanced polymeric solar reflector is compared with FE simulation results and parametric studies are conducted to investigate the effect of geometry on the accuracy of this model. Furthermore, the fracture behavior of the surface layer in the advanced polymeric solar reflector is studied using the calculated fracture ERR. Additionally, the delamination behavior, as another common failure mode of the coating/substrate structures, is then studied. The delamination fracture energy of a multilayered glass solar reflec- tor is tested by employing the width-tapered beam method. The testing results indicate that the weakest interface of the multilayered solar reflector would be the glass-copper interface with a de- lamination fracture energy 4.4 J/m2. Using the tested fracture energy as an input, an FE model is built based on the CZM and the returned peeling force from simulation is then compared with the test results to verify the accuracy of the test method. The good agreement between the simulation and test results demonstrates that the width-tapered beam method is accurate enough to measure the delamination fracture energy of this multilayered solar reflector. Additionally, the effect of aging on the delamination fracture energy is investigated by measuring the delamination fracture energy after 50 hrs’ accelerated aging test. The results show that the aging has minor effect of delamination fracture energy for samples with alumina (Al2O3) protective coating, while it reduces the delamination fracture energy for samples with titania (TiO2) protective coating. As another failure mechanism, the material degradation or aging behavior is studied in this dissertation. The weight percentage of oxygen (WPO) in three types of asphalt binders extracted from reclaimed asphalt pavements (RAPs) and one extracted from fresh Hot Mix Asphalt (HMA), that have been aged under continuous ultraviolet (UV) or UV/moisture/condensation exposure for different period, is measured using a energy-dispersive X-ray spectroscopy (EDX). Then the tested data are fitted based on two classic aging models, namely the fast-rate constant-rate (FRCR) and nonlinear differential dynamic (NDD) models. The good fitted results show that both FRCR and NDD models can capture the aging behavior of asphalt binders extracted from both RAPs and fresh HMA under continuous UV or UV/moisture/condensation exposure. Meanwhile, although exposed under UV for the same time, the WPO in samples after UV/moisture/condensation aging are lower than those in samples after continuous UV aging, which indicates that condensation and moisture reduce the UV-induced photo-oxidative aging rate.

Várias tentativas de correlacionar o tamanho da partícula e a resposta da flotação nas maiores usinas do Brasil (usinas de minério de ferro e fosfato) têm mostrado que partículas grossas (dp100 m) não flotam eficientemente. Uma vez que a suspensão de sólidos é uma condição necessária para a coleta de partículas, o estudo da suspensão de partículas grossas em células de flotação é totalmente justificado e constitui o objetivo desta tese. Neste trabalho, a suspensão de sólidos foi estudada em célula Denver e Wemco de laboratório (6 L) com os minerais apatita, quartzo e hematita, classificados como grossos (dp100 m). Estudo complementar foi realizado em célula piloto Metso (3000 L), no processamento de minério de Ni, no oeste australiano. A circulação de fluido nas células Denver e Wemco foi caracterizada pelo número de bombeamento do impelidor (NQ) e pela velocidade da água (vb), medida na descarga do impelidor, numa faixa de operação normalmente utilizada nos ensaios de flotação (900rpmN1300rpm). Para condições não-aeradas, NQ=0,043 e 12,7cm/s vb 18,3cm/s para célula Denver, e NQ=0,57 e 15,0cm/svb21,8cm/s, para Wemco. Em condições aeradas (0,05cm/sJG0,15cm/s para Denver e 0,52cm/sJG0,95cm/s para Wemco), assim como nas bombas centrífugas, a capacidade de bombeamento do impelidor diminui consideravelmente: 0,028NQ0,038 e 8,4cm/svb17,3cm/s para Denver e 0,42NQ0,53 e 11,6cm/svb 19,8cm/s para Wemco. Medidas obtidas com um transdutor de pressão, colocado próximo da região rotor/estator (células Denver e Wemco) ilustraram a capacidade dos impelidores de gerarem turbulência em células mecânicas de flotação. A rotação mínima do impelidor (Njs) em que nenhuma partícula permanece no fundo do tanque por mais do que 1 segundo (Critério 1-s de Zwietering) foi determinada para ambas a células (Denver e Wemco), em condições aeradas (Njsg) e não-aeradas (Njsu). Um modelo empírico foi utilizado para relacionar a rotação crítica de suspensão (Njs) com as propriedade sólido (diâmetro-dp, massa específica-s)-liquido (massa específica-L; concentração mássica de sólidos-X, viscosidade-)-gás (JG). Os resultados indicaram a influência dessas variáveis no valor de Njs, de acordo com o expoente de cada termo: (L)0,36-0,42> (dp)0,3> (X)0,2 > ()0,06-0,07. Através dos resultados de suspensão de apatita, levando em consideração seu tamanho e velocidade terminal (vt) e Njs foi possível relacionar o status da suspensão (segregação, suspensão e arraste) com a rotação do impelidor (N/Njsu) versus (vt/vb). Verificou-se que os valores de (N/Njsu) e (vt/vb) mais favoráveis para a suspensão de partículas grossas não são os mesmos para partículas finas. O perfil de distribuição axial de apatita (dp=127 m) em célula Denver, mostrou que quanto maior o valor de N, mas uniforme será a distribuição vertical de sólidos na célula, enquanto que em baixas rotações há uma segregação de sólidos no fundo do tanque. Quando a velocidade superficial de ar, em célula Metso, variou de JG=0,92 cm/s para JG=1,59 cm/s, aumentou a concentração de partículas grossas próximo ao fundo do tanque. O Modelo de Sedimentação-Dispersão possibilitou a identificação dos limites das zonas turbulenta e quiescente, nas células Denver e Metso. Em ambas as células, quanto maior a taxa de aeração, menor a espessura da zona turbulenta. / Several attempts to correlate particle size and flotation response at the biggest Brazilian plants (iron ore and phosphate) have concluded that coarse particles (dp 100m) do not float efficiently. As solids suspension is a necessary precondition for particle collection, the study of coarse particle suspension in mechanical cells is fully justified and it is the objective of this thesis. In this work, particle suspension was studied in laboratory Denver and Wemco flotation cells (6,0 dm3) with apatite, quartz and hematite coarse particles. Complementary study was carried out in pilot scale with a Metso (3,000 dm3) cell which processed Ni ore in Western Australia. Fluid circulation in Denver and Wemco laboratory cells was characterized by the impeller pumping number (NQ) and also by water velocity (vb) measured at the impellers discharge under a typical range of working rotational speed (900 rpm N 1,300 rpm). For ungassed conditions, Denver impeller showed NQ=0.043 and 12.7cm/s vb 18.3cm/s, whereas Wemco type showed NQ=0.57 and 15.0 cm/s vb 21.8 cm/s. Under gassed conditions (0.05 cm/s JG 0.15cm/s for Denver; 0.52 cm/s JG 0.95 cm/s for Wemco), like centrifugal pumps, the impeller pumping capacity decreased markedly: 0.028 NQ 0.038 and 8.4 cm/s vb 17.3 cm/s for Denver and 0.42 NQ 0.53 and 11.6 cm/s vb 19.8 cm/s for Wemco. Measures using a pressure transducer placed near the stator/impeller discharge region (Denver and Wemco) illustrated the ability of both impellers to create turbulence in the cells. The impellers rotational speed (N) at which no particle remains on the cell bottom for more than one second (Zwieterings 1-s Criterium) was determined for Denver and Wemco cells under gassed (Njsg) and ungassed (Njsu) conditions. An empirical model was used to correlate Njs to particle (diameter-dp, specific gravity-s)-liquid (specific gravity-L; solids mass concentration-X, viscosity-)-gas (JG) properties. The results of the model indicated a ranking for the influence of the variables on Njs based on its power: (L)0.36-0.42> (dp)0.3> (X)0.2 > ()0.06-0.07. Regarding apatite particles, taking into account its size, terminal settling velocity (vt) and Njsu, it was possible to address the status of particle suspension (segregation, suspension and dragging) to impeller rotation (N/Njsu) versus fluid velocity at the discharge of the impeller (vt/vb). It was verified that the values of (N/Njsu) and (vt/vb) more favorable to promote the suspension of the coarsest particles are not the same for the finest ones. Distribution of apatite particles (dp=127m) along the height of Denver cell indicated that when N increases, particles become more uniformly distributed along the impellers axis, whereas at lower values of N, a segregation occurs on the cell bottom. At Metso pilot cell, when air feed was increased from JG=0.92 cm/s to 1.59 cm/s, the concentration of coarse particles (D50 > 100 m) on the lower part of the cell increased markedly. The adoption of the Sedimentation-Dispersion Model to Denver and Metso cells allowed the identification of the limit of the turbulent zone versus quiescent zone within the cell. In both cells, the higher was the air flow-rate, the lower was the height of the turbulent zone.

In this thesis, we focus on the problem of interactions between solids and fluids. / The main part is the study of the motion of a rigid body immersed in an incompressible fluid. First, for the case of 2D ideal flow, a global weak solution is derived. Second, for the case of viscous flow in 3D, the problem is investigated in the Lp--framework. We get a decomposition of Lp-space associated with the problem. Then We prove that the corresponding semigroup is analytic in L65 R3∩L pR3 (p ≥ 2). Our result yields a local in time existence and uniqueness of strong solutions taking initial data in L65 R3∩L pR3 (p ≥ 3). / The other part is some research about micro-macro models of polymeric fluids. We provide a new proof for the global well-posedness of the coupling systems in 2D. / Wang, Yun. / Adviser: Zhouping Xin. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 112-119). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Made available in DSpace on 2015-04-22T22:16:05Z (GMT). No. of bitstreams: 1 Celia Maria Nogueira Batista.pdf: 1926587 bytes, checksum: f61cde4e613a60695c9ce389a0eba8b1 (MD5) Previous issue date: 2007-12-26 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / This thesis presents a new demonstration of the result FOR Plato not the fourth century BC in Ancient Greece, to que There hum Finite number of classes Poliedro Regular congruent, using a basic theory of spherical geometry, of the agreement with the work " The solid platonicos " make Dr. John Lucas Marques Barbosa University of Ceará, presented in Manaus. / Esta dissertação apresenta uma nova demostração do resultado obtido por Platão no século IV a.C, na Grécia antiga, de que existe um número finito de classes de Poliedro regulares congruentes, usando a teoria básica da Geometria Esférica, de acordo com o trabalho "Os sólidos Platônicos", do Dr. joão Lucas Marques Barbosa da Universidade do Céara, apresentado em Manaus.

O objetivo deste estudo foi avaliar o efeito da inclusão de leite em pó desnatado e de açúcar sobre a viabilidade de microrganismos probióticos e a qualidade do leite fermentado desnatado. Para isso, foram constituídos 8 tratamentos, a saber: 1. leite desnatado (LD) e padronizado com 0,2% de gordura (LD 0,2%G); 2. LD 0,2%G + 5% de leite em pó (Lp); 3. LD 0,2%G + 10% de Lp; 4. LD 0,2%G + 15% de Lp; 5. LD 0,2%G + 5% de Lp + 10% de açúcar (A); 6. LD 0,2%G + 10% de Lp + 10% de A; 7. LD 0,2%G + 15% de Lp + 10% de A; 8. LD 0,2%G + 10% de A. Foi preparada a cultura láctea mista DVS ABT-4 (Chr-Hansen) contendo Streptococcus thermophilus, Bifidobacterium animalis e Lactobacillus acidophilus, que foi aplicada em todos os tratamentos para a fermentação e produção do leite fermentado. O produto foi então envasado e armazenado a 5ºC para as análises subseqüentes. Os leites fermentados foram submetidos à avaliação físico-química, microbiológica e sensorial nos dias 1, 10 e 21 após a fabricação. Os resultados mostraram que todos os tratamentos permaneceram de acordo com a legislação brasileira no que diz respeito aos aspectos físico-químicos, além de os mesmos terem permanecido constantes durante os 21 dias de armazenamento, com exceção do pH, que diminuiu nos dias seguintes a fabricação em decorrência da pós-acidificaçao dos leites fermentados. Quanto às características microbiológicas, observou-se maiores contagens nos tratamentos com maior teor de leite em pó (tratamentos 3, 4, 6 e 7), principalmente para as bactérias probióticas, com diferença estatisticamente significativa entre todos os tratamentos. Entretanto, a adição de açúcar não interferiu nas contagens de probióticos dos leites fermentados. As contagens microbiológicas permaneceram constantes durante todos os 21 dias de armazenamento. O tratamento 6 (LD 0,2%G + 10% de Lp + 10% de A) foi o que obteve melhores notas na avaliação sensorial nos dias 1, 10 e 21 de armazenamento, indicando ser esta formulação a melhor dentre as estudadas para a aceitação do produto com maior viabilidade de bactérias probióticas. / The aim of this study was to evaluate the effect of skimmed milk powder and sugar inclusion on the viability of probiotic microorganisms and on the quality of skimmed fermented milk. Eight different treatments were prepared: 1. Skimmed and standardized milk (SM) at 0,2% of fat (SM 0,2%F); 2. SM 0,2%F + 5% of milk powder (MP); 3. SM 0,2%F + 10% MP; 4.SM 0,2%F + 15% MP; 5. SM 0,2%F + 5% MP + 5% of sugar (S); 6. SM 0,2%F + 10% MP + 5% S; 7. SM 0,2%F + 15%MP + 10%S; 8. SM 0,2%F + 10%S. The mixed lactic culture DVS ABT-4 (Chr-Hansen) containing Streptococcus thermophilus, Bifidobacterium animalis and Lactobacillus acidophilus was prepared and placed in all the treatments for the fermented milk fermentation and production. The product was bottled and stored at 5°C for the subsequent analyses. The fermented milks were submitted to physical-chemical, microbiological and sensory analyses on the 1st, 10th and 21st days after production. Results for the physic-chemical analyses showed that all the treatments comprised the requirements as adopted in Brazilian regulations. All the physical-chemical variables were constant during the 21 days of storage, except for the pH, which decreased during storage because of the fermented milks post-acidification. For the microbiological analyses, greater numbers, especially the probiotic bacteria, were obtained in treatments with higher milk powder content (treatments 3, 4, 6 and 7), with significant statistical differences among all the treatments. However, the sugar addition did not interfere with the recovery of probiotic bacteria in the fermented milks. The microbiological data were constant during the 21 days of storage. Results obtained in the sensory analyses showed that treatment 6 was the one with higher grades on days 1, 10 and 21 of storage, hence indicating that this composition is the best one among those studied for acceptability of the product with greater viability of probiotic bacteria.

Made available in DSpace on 2017-07-10T19:24:06Z (GMT). No. of bitstreams: 1 Osvaldo Kuczman.pdf: 473345 bytes, checksum: b3778df4351e601c96e945da1cf28c16 (MD5) Previous issue date: 2007-07-18 / The grouping of cassava starch production factories at northwest/west Paraná regions, Mato Grosso do Sul and São Paulo region has led to a million daily income of wastewater, which, treated at stabilization lagoons, generates greenhouse gases, unpleasant odors and landscape s degradation. The current research has evaluated the anaerobic digestion of waste cassava starch in one-phase horizontal reactor, having a 16,2 L volume, operated at 33 ± 1°C with manipueira having organic load rates of 1,28, 1,57, 2,68 and 1,18 g COD L- 1reactor day-1 for the Hydraulic Retention Times (HRT) being the experiment realization order of 12,96, 8,27 6,59 and 15,00 days, respectively. The feeding has been continuous, approaching to the real production s conditions. The cycle evaluation, for each HRT, lasted 15 days, revealing that the time didn t interfere, within 5%. The average removal in Total Solids (TS) is 98 and 77 %, Volatile Solids (VS) 99 and 90%, organic loads 96 and 95%, having as biogas yielding 0,817 and 0,604 L gas g-1 COD removed at the 8, 27 and 6,59 days, respectively. However, the most homogeneous removals in TS and VS occurred at the 12,96 and 8,27 days, not following the COD removals. The best average specific production for biogas ranged from 0,654 to 0,627 L gás L-1r d-1, verified in TRH 8,27 and 6,59 days. The average biogas methane content, come from the 15,00 days HRT, was 58,85%. The average relation Volatile Acidity/Total Alkalinity situated from 0,14 to 0,30. By the obtained results, it was concluded that it is possible to reduce the organic load of waste cassava starch through anaerobic digestion in one-phase horizontal reactor for the conditions established at the present study. / A concentração de indústrias processadoras de mandioca, nas regiões noroeste e oeste do Paraná e sul dos estados de Mato Grosso do Sul e São Paulo, produz diariamente milhões de litros de manipueira diluída que, tratada em lagoas de estabilização, geram gases de efeito estufa, maus odores e impactam a paisagem. Esse estudo avaliou a digestão anaeróbia em reator horizontal de fase única com volume de 16,2 L à temperatura de 33 ± 1 °C, alimentado com manipueira de fecularia e cargas orgânicas de 1,28, 1,57, 2,68, e 1,18 g DQO L-1r d-1 para os tempos de retenção hidráulica (TRH), sendo a ordem de realização dos experimentos de 12,96, 8,27, 6,59 e 15 dias, respectivamente. A alimentação foi contínua, aproximando-se das reais condições de geração de manipueira nas fecularias, sem correção de pH ou nutrientes. O período de avaliação diária, para cada TRH, foi de 15 dias, onde o fator tempo não interferiu ao nível de 5% de significância. As reduções médias de sólidos totais foram de 98 e 77%, sólidos voláteis de 99 e 90%, cargas orgânicas em DQO de 96 e 95% e produções de 0,817 e 0,604 L gás g- 1 DQOc nos TRH s de 8,27 e 65,9 dias, respectivamente. Porém, as reduções mais homogêneas para sólidos totais e voláteis ocorreram nos TRH s de 12,96 e 8,27 dias, não acompanhando a redução de DQO, semelhante apenas no TRH de 12,96 dias. A melhor produção específica média de biogás foi de 0,654, seguida de 0,627 L gás L-1r d-1 verificada no TRH de 8,27 e 6,59 dias e cargas orgânicas médias aplicadas de 1,57 e 2,68 g DQO L-1r d-1, respectivamente. O teor médio de metano no biogás, produzido no TRH de 15 dias, foi de 58,85%. A relação média da acidez volátil versus alcalinidade total, nos TRH s avaliados, permaneceu entre 0,14 e 0,30. A estabilização anaeróbia de manipueira em reator horizontal de fase única mostrou-se eficaz para as condições estabelecidas no presente estudo.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-31T17:58:43Z No. of bitstreams: 2 Michael Feroldi.pdf: 1564105 bytes, checksum: b0057f88efcba9ac5541c4aa3b057f63 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-31T17:58:43Z (GMT). No. of bitstreams: 2 Michael Feroldi.pdf: 1564105 bytes, checksum: b0057f88efcba9ac5541c4aa3b057f63 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The transition from fossil sources of energy for renewables in the vehicular sector has been reality in recent years and in this sense the biogas and biomethane present significant potential for use in motor vehicles. Due to several technical issues inherent in methane storage are currently employed LNG (liquefied natural gas) and CNG (compressed natural gas) technologies, which spend high amounts of energy, cylinders and heavy duty equipment for safety reasons, which makes these more expensive technologies. On the other hand, in recent years the adsorption technology with porous materials (GNA) has been studied because it employs smaller amounts of energy and also cylinders built with lighter and cheap materials. In this sense, the present work aims to evaluate the performance of activated carbon in different granulometries (A=3-5 mm, B=2 mm and C= 1-1,5 mm) in storage of methane at 10 bar using factorial planning 2², evaluating also the input parameters of a storage system prototype (flow and temperature), built for the present work. The activated carbon samples in the three granulometries were characterized by N2 fisisorption technique for the determination of texture characteristics, Helium gas pycnometry for quantification of particle density and, scanning electron microscopy and infrared spectroscopy for observation of the morphological and indication of functional surface groups. Under the conditions employed in this study, it was observed the increased ability of adsorption of carbons with a decrease in temperature in all granulometries of carbon with the variation of the input flow to the coals A and B in the range evaluated. With the present study it was possible to triple the storage capacity filled cylinder (activated carbon A = V V-1 39.41) when compared with the empty cylinder (13.14 V V-1), and still submit desorption near 100% (60 ºC and 30 min), proving the efficacy of reuse of adsorbents in cyclic tests. / A transição das fontes fósseis de energia para as renováveis no setor veicular tem sido realidade nos últimos anos e, neste sentido o biogás e o biometano apresentam potencial expressivo para utilização em veículos automotores. Devido a diversas questões técnicas inerentes ao armazenamento do metano, atualmente são empregadas as tecnologias GNL (gás natural liquefeito) e GNC (gás natural comprimido), que despendem altas quantidades de energia, cilindros e equipamentos resistentes, por questões de segurança, o que torna estas tecnologias com custos elevados. Por outro lado, nos últimos anos a tecnologia de adsorção com materiais porosos (GNA) vem sendo estudada, pois emprega menores quantidades de energia e também cilindros construídos com materiais mais leves e baratos. Neste sentido, o presente trabalho tem por objetivo avaliar o desempenho de carvões ativados em três granulometrias (A=3-5 mm, B=2 mm e C= 1-1,5 mm) no armazenamento de metano a 10 bar, utilizando planejamento fatorial 2², avaliando também parâmetros de entrada de um sistema de armazenamento protótipo (vazão e temperatura), construído para condução do presente trabalho. As amostras de carvão ativado nas três granulometrias foram caracterizadas pelas técnicas de fisissorção de N2, para determinação das características texturais, picnometria de gás Hélio, para quantificação da densidade das partículas e, microscopia eletrônica de varredura e espectroscopia de infravermelho para observação da estrutura morfológica e indicação de grupos funcionais de superfície. Nas condições empregadas neste estudo, foi observado o aumento da capacidade de adsorção dos carvões com a diminuição da temperatura em todas as granulometrias do carvão e com a variação da vazão de entrada para os carvões A e B no intervalo avaliado. Com o presente estudo foi possível triplicar a capacidade de armazenamento do cilindro preenchido (carvão A = 39,41 V V-1) quando comparado com o cilindro vazio (13,14 V V-1) e, ainda, apresentarem dessorção próxima a 100% (60 ºC e 30 min), comprovando o reuso dos adsorventes em ensaios cíclicos.

Neste trabalho, foram levantados dados sobre o tratamento da água e os resíduos gerados nos decantadores e filtros da ETA Fonte Luminosa, localizada em Araraquara, que é do tipo convencional com decantadores de alta taxa, objetivando-se obter parâmetros sobre a qualidade e quantidade dos resíduos gerados na ETA referida. Foram analisados e relacionados fatores relevantes na geração e composição destes resíduos, tais como: consumo de produtos químicos, procedimentos operacionais e qualidade da água bruta. O trabalho foi dividido em três etapas. Na primeira, foi realizada a caracterização física e operacional da ETA Fonte Luminosa através de visitas e levantamento de dados históricos da água afluente à estação, da água tratada, dos produtos químicos e dos dados operacionais da estação no período de 2001 a 2003. Na segunda etapa, realizou-se a caracterização qualitativa da água nas diversas etapas do tratamento em termos de pH, cor aparente, turbidez e sólidos; nos resíduos originados nos decantadores e filtros, também, foi realizada a caracterização qualitativa (DQO, nitrogênio total, fosfato total, pH, cor aparente, turbidez e sólidos) e quantitativa (medida e estimada com o emprego de balanço de massas) dos. A ultima etapa, foi a avaliação da ocorrência de metais (Fe, Cd, Zn, Ni, Cu, Pb, Cr e Mg) na água ao longo do tratamento e nos resíduos. Os processos e as operações empregadas no tratamento influenciaram diretamente na qualidade e na quantidade dos resíduos. No período observado, os resultados indicaram grande semelhança entre os resíduos gerados nos decantadores de alta taxa e filtros da ETA Fonte Luminosa. Notou-se grande divergência entre os resíduos gerados em decantadores convencionais (ETA São Carlos) e de alta taxa (descargas diárias). Observou-se a ocorrência de chumbo, níquel e cromo total na água tratada em valores acima do Padrão de Potabilidade fixado pela Portaria nº 518/MS de 25/03/2004. / In this work, it was made a data survey about the water treatment and the residuals generated in the settling tanks and filters from the Fonte Luminosa WTA located at Araraquara-SP, a conventional type WTA with high rate settling tanks; aiming to obtain parameters about the quality and quantity of residuals generated at this WTA. The relevant parameters in the residuals generation and composition, like the chemical consume, the operational proceedings and the raw water quality, were evaluated and related to each other. The work was divided in three stages. In the first, it was made the physic and operational characterization from the Fonte Luminosa WTA by means of visits and historical data surveys from the water that enters the WTA, the treated water, the chemicals used and the operational data from the period of 2001 to 2003. In the second stage, it was made a qualitative characterization from the water in several stages of the treatment, with the parameters: pH, apparent color, turbidity and solids; to the residuals generated in the settling tanks and filters, it was also made the qualitative characterization with the parameters: COD, total nitrogen, total phosphate, pH, apparent color, turbidity and solids; and it was made a quantitative characterization for these residuals (measured and estimated by the mass balance). The last stage was the evaluation of the occurrence of metals (Fe, Cd, Zn, Ni, Cu, Pb, Cr and Mg) in the total water treatment and in the residuals. The processes and operations applied in the water treatment have a direct influence in the quality and quantity of the generated wastes. In the observed period, the results show a great similarity between the wastes generated in the high rate settling tanks and filters from this WTA. It was observed a great difference between the residuals generated in conventional settling tanks (São Carlos WTA) and high rate settling tanks (daily discharge). It was observed the occurrence of lead, nickel and chrome in the treated water, with values bigger than the ones fixed by the Portaria nº 518/MS from 03/25/2004 to a drinking water.

Whilst biodiesel has many advantages as a renewable-energy fuel and as a substitute source of petroleum diesel, it suffers from poor performance at both low temperatures and high pressures. Not only does biodiesel crystallise at low temperatures below ~0 °C, but it also crystallises under the high pressures experienced in common-rail and injector systems within diesel engines. Crystalline solids induced by temperature and pressure can clog filters and injectors in the diesel engine, thereby causing engine failure. This thesis focuses on developing an enhanced understanding of the behaviour of biodiesel using a range of spectroscopy and diffraction techniques. The crystallisation behaviour of biodiesel at high pressure (0.1 GPa to 4 GPa) or low temperature (0 °C to -40 °C) was studied in this work. Structural phase transitions of the components of biodiesel induced by both temperature and pressure were observed. On account of the complex nature of biodiesel, it proved difficult to characterise these changes in biodiesel itself. Instead, one of the main components, methyl stearate, was therefore investigated. The crystallisation behaviour of methyl stearate is temperature-sensitive. A new polymorph of form II was successfully characterised by single crystal diffraction - by growing crystals from a saturated carbon disulfide solution at room temperature while data collection was conducted at 120 K. Form III was obtained by crystallisation from melt followed by slow cooling. Structural characterisation using single crystal diffraction showed disordered packing behaviour of the molecules in this form. The crystal structure of form IV was obtained using a combination of synchrotron X-ray powder diffraction and high resolution neutron powder diffraction. It was crystallised from the melt by quench cooling at low temperature. The thermal expansion behaviour of this form was also investigated in this work. Furthermore, a phase transition from form IV to form V was observed in neutron diffraction experiments for a fully deuterated sample, but no evidence for this transition was observed in X-ray diffraction studies. Due to the complexity of methyl stearate and the limitations of the experimental data, the crystal structure of form V was not solved. In addition to the temperature studies, the crystallisation behaviour of methyl stearate under variable pressure conditions was investigated in this work. A diamond-anvil cell was employed to generate high-pressure environments. Synchrotron high-pressure X-ray powder diffraction and Raman spectroscopy showed that pressures of as little as 0.1 GPa can induce form IV of methyl stearate to convert to form II. Four phase transitions in the pressure range of 0.1 GPa to 6.3 GPa were also observed. The phase behaviour of methyl stearate induced by pressure is reversible and form II was recovered when the pressure was released. The structure of these high-pressure phases of methyl stearate have still to be determined. High-pressure neutron powder diffraction experiments have also been conducted with form IV of methyl stearate using a Paris-Edinburgh Press. Fluorinert (FC-87) was employed as pressure-transmitting medium to generate hydrostatic condition. No evidence of a phase transition was observed in the pressure range up to 3.31 GPa.