Silica gels containing incorporated heteropolyacids (HPAs) were synthesized in acidic media by co-condensation of tetraethoxysilane (TEOS) with phosphotungstic or phosphomolybdic acids using the sol-gel technique. The effect of the synthesis conditions on their structure and morphology was studied. Yields of modified materials were somewhat lower compared to non-modified silica gels. All materials were mesoporous but contained micropores in their structures. Presence of bands of Keggin's structures in FT-IR spectra along with absence of XRD patterns of crystalline HPAs confirmed their fine incorporation into silica network. Particle sizes of modified materials were 500-1100 nm except for the W-containing sample obtained with trimethylstearylammonium chloride, which was significantly lower. This unusual effect was attributed to stabilization of primary silica nanoparticles by interactions between the surfactant and HPA. High ratio HPA/TEOS resulted in partial loss of porosity. Obtained results might be used for optimization of synthesis of effective catalysts and adsorbents containing HPAs in mesoporous structure.

NOx (NO, NO2) is one of the most harmful air-pollutants from exhaust, resulting in series of environmental problems as well as severe healthy issues for human beings. Selective catalytic reduction (SCR) system is a common approach to eliminate NOx onboard by using ammonia as a reductant. However, ammonia storage unit has been one of the restriction factors for the NOx conversion efficiency because of insufficient ammonia dosing rate and the corrosive and hazardous nature of ammonia. Thus, a reliable ammonia storage and delivery system is of high scientific and commercial desire. In this thesis, novel composites were fabricated and studied based on MgCl2 and SrCl2, two commercial alkaline earth metal halides (AEMH) for ammonia storage. In order to reduce the melting issue and enhance the kinetics of the ammonia sorption, carbon materials, graphite (Gt) and graphene nanoplatelets aggregates (GNA) were added to MgCl2 at 1 wt.%, 10 wt.% and 20 wt.%. With ball milling and hydraulic pressing, the aforementioned carbon-MgCl2 composites were structured into pellets for various characterization. With real-time recording in the tube furnace at 1073 K, we observed that with 20% carbon additives, the pelletized composites maintained their structure with 95% mass retention, while the pure MgCl2 completely melted and disintegrated. According to the SEM images, carbon materials separated MgCl2 so that the molten MgCl2 cannot form large droplet to spread out. Furthermore, the 20 wt.% GNA-80 wt.% MgCl2 (GNA20) composites demonstrated enhanced kinetics in both absorption and desorption of ammonia, which is 83% faster in ammonia absorption and 73% faster in desorption in the first two minutes compared to the pure MgCl2. The BET surface area and mercury intrusion porosimetry results explains the kinetic elevation by the GNA by introducing extra reaction surface and nanopores as the diffusion path for ammonia. The enhancement of both structural stabilityand kinetics make the GNA20 composite a robust ammonia carrier. During the chemical absorption process, SrCl2 uptakes 8 ammonia molecules resulting in 4 times volume expansion. This dramatic expansion and shrinkage during the absorption and desorption will destroy the structure and disintegrate the SrCl2 into powder, which could bring the dust explosion risk for many applications. Based on the carbon-salts composites, a novel porous SrCl2 structure is designed and fabricated with graphene oxide as skeleton by freeze casting process. Porous SrCl2 structure is feasible for various geometries with different molds at a wide SrCl2 load from 0 wt.% to 96 wt.%. The ammonia capacity of the porous SrCl2 is linear proportional to the SrCl2 load. During the ammonia absorption and desorption cycles, the graphene oxide skeleton could self-adjust along with the volume swing to within its flexibility. This porous SrCl2 demonstrates excellent tolerance of volume swing and enhanced kinetics as a promising ammonia storage material. Our approach and results may cast light on the obstacles of structuring self-expansion and shrinkage materials as well as on enhancing the gas sorption properties.

No description available.

Programmable matter is a material whose properties can be programmed to achieve particular shapes or mechanical properties upon command. This is an essential technique that could one day lead to morphing aircraft and ground vehicles. Metamaterials are the rationally designed artificial materials whose properties are not observed in nature. Their properties are typically controlled by geometry rather than chemical compositions. Combining metamaterials with a programmable function will create a new area in the intelligent material design. The objective of this study is to design and demonstrate a tunable metamaterial and to investigate its thermo-mechanical behavior. An integrated approach to the metamaterial design was used with analytical modeling, numerical simulation, and experimental demonstration. The dynamic thermo-mechanical analysis was used to measure base materials' modulus and thermal expansion coefficient as a function of temperature. CPS, the unit cell of the metamaterial, is composed of circular holes and slits. By decomposing kinematic rotation of the arm and elastic deformation of a bi-material hinge, thermo-mechanical constitutive models of CPS were developed and it was extended to 3D polyhedral structures for securing isotropic properties. Finite element based numerical simulations of CPS and polyhedral models were conducted for comparison with the analytical model. 3D printing of multi-materials was used for sample fabrication followed by tests with uniaxial compressive mechanical tests and thermal tests at 50℃. From the analytical model of the metamaterial, the contour plots were obtained for the effective properties – Poisson's ratio, the effective coefficient of thermal expansion of the metamaterial as a function of geometry and materials. A controllable range of temperature and strain was identified associated with maximized thermal expansion mismatch and contact on the slit surface of CPS, respectively. This work will pave the road toward the design of programmable metamaterials with both mechanically- and thermally- tunable capability and provide unique thermo-mechanical properties with a programmable function.

Neste trabalho são apresentados resultados experimentais do processo de filtração tangencial de uma suspensão in natura (soro de leite) aplicada na retenção de bactérias do grupo coliforme. No estudo do processo de separação utilizaram-se tubos microporosos de -alumina (Al2O3) e membranas comerciais de tamanho médio de poros no valor de 0,8 e 1,2m. Os tubos microporosos cerâmicos foram sinterizados à temperatura entre 1400 e 1450ºC, os quais foram caracterizados pela técnica de porosimetria por intrusão de mercúrio, constatando o tamanho médio de poros de 0,3 a 0,5µm. Após a sinterização, os tubos cerâmicos foram sujeitos à impregnação com citrato de prata (material bactericida). As membranas comerciais também passaram pelo mesmo processo de impregnação. Com o uso da técnica de microscopia eletrônica de varredura (MEV) foi realizada uma caracterização da morfologia e da composição dos meios microporosos. Ensaios experimentais do processo de microfiltração foram realizados com soro de leite, com o objetivo de estudar a influência de parâmetros fluidodinâmicos tais como: número de Reynolds e pressão transmembrana, além de analisar a retenção da bactéria, Escherichia coli, em regime de escoamento para Reynolds entre 2700 e 32000 e pressões transmembrana entre 1 e 4 bar. O permeado foi analisado seguindo normas da 20ª. Edição dos Métodos Padrões para Análise de Água e Esgoto, e todos os experimentos seguiram padrões de segurança para minimizar a possibilidade de contaminação do meio junto à análise do material filtrado. A manutenção fisiológica das bactérias foi controlada com os parâmetros de pH e temperatura, respectivamente mantidos entre 6 e 7,0 e de 25 - 30ºC ± 1 ºC. Nestas condições de escoamento, da solução e do meio filtrante, o processo foi considerado satisfatório com vazões transmembrana entre 10 L/(h.m2) e 120 L/(h.m2). / This work reports experimental results of the crossflow microfiltration of emulsion (whey of milk) applied in the microrganism retention of the coliform group. In the study of the separation process were used micro-porous tubes of -alumina (Al2O3) and commercial membranes of average size pores of 0,8 and 1,2m. The micro-porous tubes were sinterised with temperature between 1400 and 1450 ºC and after, were characterized by technique of porosimetry for mercury intrusion, verifing average size of pores between 0,3 and 0,5µm. After the sintering, the ceramic tubes were treated with a citrate of silver solution (bactericidal substance), and submitted to synthesis for removed the organic matters. The commercial membranes were also impregnated by this process. With the scanning eletronic microscopy made the characterization of the morfology and micro-porous structures composition. Experimental tests of the crossflow microfiltration process were performed with whey of milk, with objective to study the influence of fluid dynamics parameters (Reynolds number and flux transmembrane) and to analyse the bacteria retention in turbulent regime, having Re between 2700 and 32000, transmembrane pressure (enters 1 to 4bar) and transmembrane flux between 0,5 and 300 L/h.m2. The permeate was analysed by the 20ª. Edition of the Standard Methods for Examination of Water, and all the experiments followed standards of security to restrict the possibility of contamination of the permeated and the atmosphere. The physiology of the bacteria was controlled by parameters of pH and temperature, respectively keeped between 6 and 7,0 and of 25 - 30ºC ± 1 ºC. In the conditions of flow, of the solution and system flow, the retention was considerated satisfactory with transmembrane flux between 10 L/(h.m2) and 120L/(h.m2).

O trabalho tem por objetivo apresentar procedimentos de projeto e execução de obras de pavimentos permeáveis visando sua aplicação prática como medidas compensatórias de drenagem urbana com a finalidade de retenção e amortecimento de picos de enchentes em cidades densamente urbanizadas. Os procedimentos propostos se baseiam na experiência adquirida para a implementação de dois tipos de pavimentos permeáveis; um com revestimento constituído de blocos intertravados de concreto e outro com revestimento de concreto asfáltico poroso, conhecido como camada porosa de atrito. Para subsidiar o trabalho uma pista experimental foi construída como área de estacionamento nas dependências do Centro Tecnológico de Hidráulica CTH na Universidade de São Paulo onde foi realizado o experimento. O local do estacionamento atua como um reservatório subsuperficial de águas pluviais sendo que sua estrutura, constituída de agregados granulares, abriga no interior de seus vazios a água infiltrada pelas camadas do pavimento. Recomenda-se, após os estudos, que os procedimentos e seqüências de atividades de projeto e execução de obras de pavimentos permeáveis sejam contemplados pelo poder público e privado como solução alternativa em diferentes empreendimentos urbanos como grandes áreas públicas ou particulares, estacionamentos, parques, quadras esportivas, passeios, calçamentos e ruas de pouca solicitação de tráfego entre outros. / The present work intents to show design and built procedures, of porous pavements; by paying attention on its practical appliances as compensatory option in urban drainage with purpose to retaining rainfall water by storage, reducing downstream flooding in cities with great urban density. The procedures here proposed are based in the know how acquired for the construction of two kinds of porous pavements: one built with interlocked concrete blocks and the other built with porous asphalt. In order to aid the present work, an experimental field was built as parking area inside the propriety of CTH Centro Tecnologico de Hidraulica in State University of Sao Paulo where the tests and experiments were made. The parking area is a reservoir structure where rain water is stored inside courses of aggregates. The storage volume is in the void space between particles of material that comes by infiltration trough the pavement layer. The commendation, after the studies, is that procedures and activities of design and build of porous pavements could be observed by government and private sector as alternative solution in many kinds of urban projects such as large public and private lots, parking areas sport fields side walks and streets, with low capacity of traffic loads, and so forth.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho, copolímeros à base de acrilonitrila e divinilbenzeno foram sintetizados, utilizando a técnica de polimerização em suspensão, na presença de três agentes porogênicos diferentes (álcool isoamílico, metil-etil-cetona e tolueno). Esses copolímeros foram caracterizados por meio da determinação da densidade aparente, do volume e diâmetro de poros, por microscopia ótica e microscopia eletrônica de varredura e foram avaliados quanto à capacidade de inchamento em heptano e tolueno. O principal intuito dessa pesquisa foi correlacionar a formação da estrutura porosa desses materiais com os principais parâmetros de síntese (grau de diluição dos monômeros, poder solvatante do diluente e teor do agente de reticulação). Desses parâmetros, o que mais influenciou na formação da estrutura porosa desses materiais foi o poder solvatante do diluente. A teoria dos parâmetros de solubilidade de Hansen e Hildebrand foi utilizada com o intuito de fazer uma previsão das características porosas dos copolímeros à base de acrilonitrila e divinilbenzeno sintetizados na presença de três diluentes diferentes. Dentre esses diluentes, o álcool isoamílico foi o pior solvente para os copolímeros de AN-DVB, em todos os teores de agente de reticulação e em todas as diluições utilizadas. O tolueno foi o melhor solvente para os copolímeros que contêm altos teores de agente de reticulação. Estas observações estão de acordo com as previsões dos parâmetros de solubilidade de Hansen e Hildebrand. A metil-etil-cetona foi o melhor solvente para os copolímeros que contêm teores intermediários de agente de reticulação. Esta observação só está condizente com o parâmetro de solubilidade de Hansen. / In this work, acrylonitrile-divinylbenzene copolymers were synthesized using the technique of suspension polymerization in the presence of three different solvents (isoamyl alcohol, methyl-ethyl-ketone and toluene). These copolymers were characterized by apparent density, pore volume and pore diameter, optical and scanning electron microscopy, and were evaluated for their ability to swell in heptane and toluene. The principal aim of this research was to correlate the porous structure formation of these materials, with the main synthesis parameters (degree of dilution, solvating power of the diluent and crosslinking degree). Among these parameters, the most important on the formation of the materials porous structure was the solvating power of the diluent. The theory of solubility parameters of Hansen and Hildebrand was used in order to make a prediction of the porous characteristics of acrylonitrile-divinylbenzene copolymers synthesized in the presence of three different diluents. Among these solvents, the isoamyl alcohol was the worst solvent for acrylonitrile-divinylbenzene copolymers, at all levels of crosslinking degree and at all dilutions used. Toluene was the best solvent for the copolymers containing high levels crosslinking degree. These observations are consistent with the predictions of the solubility parameters of Hansen and Hildebrand. The methyl-ethyl-ketone was the best solvent for the copolymers containing intermediate crosslinking degree. This observation is only consistent with the Hansen solubility parameters. In this work, acrylonitrile-divinylbenzene copolymers were synthesized using the technique of suspension polymerization in the presence of three different solvents (isoamyl alcohol, methyl-ethyl-ketone and toluene). These copolymers were characterized by apparent density, pore volume and pore diameter, optical and scanning electron microscopy, and were evaluated for their ability to swell in heptane and toluene. The principal aim of this research was to correlate the porous structure formation of these materials, with the main synthesis parameters (degree of dilution, solvating power of the diluent and crosslinking degree). Among these parameters, the most important on the formation of the materials porous structure was the solvating power of the diluent. The theory of solubility parameters of Hansen and Hildebrand was used in order to make a prediction of the porous characteristics of acrylonitrile-divinylbenzene copolymers synthesized in the presence of three different diluents. Among these solvents, the isoamyl alcohol was the worst solvent for acrylonitrile-divinylbenzene copolymers, at all levels of crosslinking degree and at all dilutions used. Toluene was the best solvent for the copolymers containing high levels crosslinking degree. These observations are consistent with the predictions of the solubility parameters of Hansen and Hildebrand. The methyl-ethyl-ketone was the best solvent for the copolymers containing intermediate crosslinking degree. This observation is only consistent with the Hansen solubility parameters.

Carbonaceous deposits accumulate on the majority of the inner surfaces of internal combustion engines. The presence of these deposits is known to cause impaired engine performance. This is manifested as increased knocking, higher fuel consumption, higher emissions and other adverse effects. One of the proposed mechanisms for this behaviour is the adsorption and desorption of fuel components in the pores within the deposit. The porous nature of the deposits promotes this behaviour, altering the fuel composition and reducing the amount of fuel entering the combustion chamber. Previous research in this area was aimed at determining the porous structure of the deposits by combining experimental procedures with molecular simulations to investigate adsorption interactions with fuel components. Using a characterisation procedure regularly applied to activated carbons, a molecular model was developed that was able to provide new insights into the deposit structure. This model enabled predictions to be made for the single-component adsorption of normal heptane and iso-octane, two species commonly used as a gasoline reference fuel. Results showed significant adsorption of both species, and highlighted the impact of adsorption into the internal porous structure of the engine deposits. The aim of this thesis is to further investigate adsorption in engine deposits by expanding the studies to more complex systems. We develop a model to predict the adsorption of normal heptane, iso-octane, toluene and their mixtures in deposits of different origins and under different conditions. The study of multi-component mixtures provides insight into selectivity effects of adsorption under confinement, while at the same time bringing the systems under consideration closer to realistic multi-component mixtures that better represent fuel blends. The study also considers for the first time adsorption of aromatic species, both as a single component and in mixtures, since aromatics have a high presence in gasoline fuel. We explore the influence of molecular structure of adsorbing species, composition of the bulk mixture and temperature on the uptake and selectivity behaviour of the engine deposits. We demonstrate that under equilibrium conditions, deposits can adsorb substantial amounts of hydrocarbon species of all types. However, selectivity behaviour in engine deposits was found to be a subtle and complex property, highly sensitive to both pore size and system pressure.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho, copolímeros à base de acrilonitrila e divinilbenzeno foram sintetizados, utilizando a técnica de polimerização em suspensão, na presença de três agentes porogênicos diferentes (álcool isoamílico, metil-etil-cetona e tolueno). Esses copolímeros foram caracterizados por meio da determinação da densidade aparente, do volume e diâmetro de poros, por microscopia ótica e microscopia eletrônica de varredura e foram avaliados quanto à capacidade de inchamento em heptano e tolueno. O principal intuito dessa pesquisa foi correlacionar a formação da estrutura porosa desses materiais com os principais parâmetros de síntese (grau de diluição dos monômeros, poder solvatante do diluente e teor do agente de reticulação). Desses parâmetros, o que mais influenciou na formação da estrutura porosa desses materiais foi o poder solvatante do diluente. A teoria dos parâmetros de solubilidade de Hansen e Hildebrand foi utilizada com o intuito de fazer uma previsão das características porosas dos copolímeros à base de acrilonitrila e divinilbenzeno sintetizados na presença de três diluentes diferentes. Dentre esses diluentes, o álcool isoamílico foi o pior solvente para os copolímeros de AN-DVB, em todos os teores de agente de reticulação e em todas as diluições utilizadas. O tolueno foi o melhor solvente para os copolímeros que contêm altos teores de agente de reticulação. Estas observações estão de acordo com as previsões dos parâmetros de solubilidade de Hansen e Hildebrand. A metil-etil-cetona foi o melhor solvente para os copolímeros que contêm teores intermediários de agente de reticulação. Esta observação só está condizente com o parâmetro de solubilidade de Hansen. / In this work, acrylonitrile-divinylbenzene copolymers were synthesized using the technique of suspension polymerization in the presence of three different solvents (isoamyl alcohol, methyl-ethyl-ketone and toluene). These copolymers were characterized by apparent density, pore volume and pore diameter, optical and scanning electron microscopy, and were evaluated for their ability to swell in heptane and toluene. The principal aim of this research was to correlate the porous structure formation of these materials, with the main synthesis parameters (degree of dilution, solvating power of the diluent and crosslinking degree). Among these parameters, the most important on the formation of the materials porous structure was the solvating power of the diluent. The theory of solubility parameters of Hansen and Hildebrand was used in order to make a prediction of the porous characteristics of acrylonitrile-divinylbenzene copolymers synthesized in the presence of three different diluents. Among these solvents, the isoamyl alcohol was the worst solvent for acrylonitrile-divinylbenzene copolymers, at all levels of crosslinking degree and at all dilutions used. Toluene was the best solvent for the copolymers containing high levels crosslinking degree. These observations are consistent with the predictions of the solubility parameters of Hansen and Hildebrand. The methyl-ethyl-ketone was the best solvent for the copolymers containing intermediate crosslinking degree. This observation is only consistent with the Hansen solubility parameters. In this work, acrylonitrile-divinylbenzene copolymers were synthesized using the technique of suspension polymerization in the presence of three different solvents (isoamyl alcohol, methyl-ethyl-ketone and toluene). These copolymers were characterized by apparent density, pore volume and pore diameter, optical and scanning electron microscopy, and were evaluated for their ability to swell in heptane and toluene. The principal aim of this research was to correlate the porous structure formation of these materials, with the main synthesis parameters (degree of dilution, solvating power of the diluent and crosslinking degree). Among these parameters, the most important on the formation of the materials porous structure was the solvating power of the diluent. The theory of solubility parameters of Hansen and Hildebrand was used in order to make a prediction of the porous characteristics of acrylonitrile-divinylbenzene copolymers synthesized in the presence of three different diluents. Among these solvents, the isoamyl alcohol was the worst solvent for acrylonitrile-divinylbenzene copolymers, at all levels of crosslinking degree and at all dilutions used. Toluene was the best solvent for the copolymers containing high levels crosslinking degree. These observations are consistent with the predictions of the solubility parameters of Hansen and Hildebrand. The methyl-ethyl-ketone was the best solvent for the copolymers containing intermediate crosslinking degree. This observation is only consistent with the Hansen solubility parameters.

O trabalho tem por objetivo apresentar procedimentos de projeto e execução de obras de pavimentos permeáveis visando sua aplicação prática como medidas compensatórias de drenagem urbana com a finalidade de retenção e amortecimento de picos de enchentes em cidades densamente urbanizadas. Os procedimentos propostos se baseiam na experiência adquirida para a implementação de dois tipos de pavimentos permeáveis; um com revestimento constituído de blocos intertravados de concreto e outro com revestimento de concreto asfáltico poroso, conhecido como camada porosa de atrito. Para subsidiar o trabalho uma pista experimental foi construída como área de estacionamento nas dependências do Centro Tecnológico de Hidráulica CTH na Universidade de São Paulo onde foi realizado o experimento. O local do estacionamento atua como um reservatório subsuperficial de águas pluviais sendo que sua estrutura, constituída de agregados granulares, abriga no interior de seus vazios a água infiltrada pelas camadas do pavimento. Recomenda-se, após os estudos, que os procedimentos e seqüências de atividades de projeto e execução de obras de pavimentos permeáveis sejam contemplados pelo poder público e privado como solução alternativa em diferentes empreendimentos urbanos como grandes áreas públicas ou particulares, estacionamentos, parques, quadras esportivas, passeios, calçamentos e ruas de pouca solicitação de tráfego entre outros. / The present work intents to show design and built procedures, of porous pavements; by paying attention on its practical appliances as compensatory option in urban drainage with purpose to retaining rainfall water by storage, reducing downstream flooding in cities with great urban density. The procedures here proposed are based in the know how acquired for the construction of two kinds of porous pavements: one built with interlocked concrete blocks and the other built with porous asphalt. In order to aid the present work, an experimental field was built as parking area inside the propriety of CTH Centro Tecnologico de Hidraulica in State University of Sao Paulo where the tests and experiments were made. The parking area is a reservoir structure where rain water is stored inside courses of aggregates. The storage volume is in the void space between particles of material that comes by infiltration trough the pavement layer. The commendation, after the studies, is that procedures and activities of design and build of porous pavements could be observed by government and private sector as alternative solution in many kinds of urban projects such as large public and private lots, parking areas sport fields side walks and streets, with low capacity of traffic loads, and so forth.