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Estudo cin?tico da degrada??o t?rmica e catal?tica de petr?leo pesado usando Al-MCM-41Oliveira, Aline Ara?jo Alves de 09 August 2013 (has links)
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Previous issue date: 2013-08-09 / The mesoporous nanostructured materials have been studied for application in
the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000
m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large
molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal
method, on which aluminum was added, in the ratio Si/Al equal to 50, to increase the
generation of active acid sites in the nanotubes. The catalyst was characterized by X-ray
diffraction (XRD), surface area by the BET method and, the average pore volume BJH
method using the N2 adsorption, absorption spectroscopy in the infrared Fourier
Transform (FT-IR) and determination of surface acidity with application of a probe
molecule - n-butylamine. The catalyst showed well-defined structural properties and
consistent with the literature. The overall objective was to test the Al-MCM-41 as
catalyst and thermogravimetric perform tests, using two samples of heavy oil with API ?
equal to 14.0 and 18.5. Assays were performed using a temperature range of 30-900 ? C
and heating ratios (β) ranging from 5, 10 and 20 ?C min-1.The aim was to verify the
thermogravimetric profiles of these oils when subjected to the action of the catalyst Al-
MCM-41. Therefore, the percentage ranged catalyst applied 1, 3, 5, 10 and 20 wt%, and
from the TG data were applied two different kinetic models: Ozawa-Flynn-Wall (OFW)
and Kissinger-Akahrira-Sunose (KAS).The apparent activation energies found for both
models had similar values and were lower for the second event of mass loss known as
cracking zone, indicating a more effective performance of Al-MCM-41 in that area.
Furthermore, there was a more pronounced reduction in the value of activation energy
for between 10 and 20% by weight of the oil-catalyst mixture. It was concluded that the
Al-MCM-41 catalyst has applicability in heavy oils to reduce the apparent activation
energy of a catalyst-oil system, and the best result with 20% by weight of Al-MCM-41 / Os materiais mesoporosos nanoestruturados vem sendo estudados para aplica??o
na ind?stria do petr?leo, em especial o Al-MCM-41, devido ? ?rea superficial em torno
de 800-1000 m2g-1 e di?metro de poros variando de 2 a 10 nm, adequado para cat?lise
de mol?culas grandes como petr?leos pesados. O MCM-41 foi sintetizado pelo m?todo
hidrot?rmico, o qual foi adicionado Alum?nio numa propor??o Si/Al igual ? 50, a fim de
aumentar a gera??o de s?tios ?cidos ativos nos nanotubos. O catalisador foi
caracterizado por difra??o de Raios-X (DRX), ?rea superficial pelo m?todo BET e
volume m?dio de poros pelo m?todo BJH atrav?s da adsor??o de N2, espectroscopia de
absor??o na regi?o do infravermelho por Transformada de Fourier (FT-IR) e
determina??o da acidez superficial com aplica??o de uma mol?cula sonda nbutilamina.
O catalisador apresentou propriedades estruturais bem definidas e coerentes
com a literatura. O objetivo geral foi testar o Al-MCM-41 como catalisador e realizar
ensaios termogravim?tricos, utilizando duas amostras de petr?leo pesado com ?API
iguais ? 14,0 e 18,5. Os ensaios foram realizados usando uma faixa de temperatura de
30 900?C, e raz?es de aquecimento (β) variando de 5, 10 e 20 ?Cmin-1. O intuito era
verificar os perfis termogravim?tricos destes petr?leos quando submetidos ? a??o do
catalisador Al-MCM-41. Para tanto, variou-se o percentual de catalisador aplicado in
situ: 1, 3, 5, 10 e 20% em massa e, a partir dos dados termogravim?tricos foram
aplicados dois modelos cin?ticos diferentes: Ozawa-Flynn-Wall (OFW) e Kissinger-
Akahrira-Sunose (KAS). As energias de ativa??o aparente encontradas para ambos os
modelos tinham valores semelhantes e eram menores para o segundo evento de perda de
massa conhecido como zona de craqueamento, indicando uma atua??o mais efetiva do
Al-MCM-41 nessa zona. Al?m disso, constatou-se uma diminui??o mais acentuada no
valor das energias de ativa??o para valores entre 10 e 20% em massa da mistura
catalisador-?leo. Concluiu-se que o Al-MCM-41 possui aplicabilidade catal?tica em
petr?leos pesados diminuindo a energia de ativa??o aparente de um sistema catalisador?leo,
sendo o melhor resultado com 20% em massa de Al-MCM-41
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Discussão de uma metodologia para diagnóstico e ações para redução de perdas de água: aplicação no sistema de abastecimento de água da Região Metropolitana de São Paulo. / Discussion of a methodology for diagnosis and actions to reduce water losses: application in the water supply system in metropolitan region of Sao Paulo.Débora Soares Melato 01 April 2010 (has links)
O presente trabalho apresenta uma discussão de metodologia para o diagnóstico e ações para redução de perdas de água, auxiliando na determinação do perfil das perdas, permitindo uma melhor priorização das ações de combate e redução de perdas reais (físicas) e perdas aparentes (comerciais). Para o desenvolvimento desta metodologia, foi realizada uma ampla revisão bibliográfica, onde é apresentada a conceituação geral sobre perdas de água, suas causas e ocorrências, indicadores, ações para redução, e uma abordagem detalhada quanto às metodologias existentes para avaliação de perdas e ferramentas disponíveis para isto. A metodologia aqui aplicada desenvolve a avaliação das perdas através do balanço hídrico, utilizando o software gratuito desenvolvido pelo Banco Mundial (W-B Easy Calc - v1.17), e foi aplicada no sistema de abastecimento de água da Região Metropolitana de São Paulo (RMSP). Foram levantados os dados básicos de controle do sistema e realizados ensaios de campo, com medições de pressão e ensaios para determinação das perdas aparentes. Como estudo de caso, a metodologia foi aplicada em três setores de abastecimento da área central da RMSP, com características distintas. Os resultados do diagnóstico das perdas foram coerentes com as expectativas. Em função dos resultados, em cada setor deverá ser desenvolvida uma estratégia específica para a redução de perdas. / This study presents a discussion of a methodology for diagnosis and actions to reduce water losses, to assist in determining the profile of water losses, allowing a better prioritization of actions to combat and reduce real (physical) losses and apparent (commercial) losses. For developing the methodology, it was conducted an extensive bibliography review, where is presented the general concepts on water losses, its causes and events, indicators, actions to reduce, and a detailed discussion about the existing methodologies to assess losses and tools available for this. The applied methodology consists of an assessment of losses through the water balance, using free software developed by the World Bank (WB Easy Calc - v1.17) and it was applied in the water supply system in metropolitan region of Sao Paulo. To do this, it was necessary to collect basic data of system control and field tests, with pressure measurements and tests to determine apparent losses. As case study, the methodology was applied in three supply zones at the central area of metropolitan region of Sao Paulo, with different characteristics. The results of water losses diagnosis were consistent with expectations. With these results, a specific strategy should be developed in each sector for reducing losses.
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Influência do tamanho molecular aparente de substâncias húmicas aquáticas na eficiência da coagulação por hidroxicloreto de alumínio / Influence of apparent molecular size from aquatic humic substances in the efficiency of coagulation by aluminum hydroxychlorideSantos, Camila Tolledo 16 November 2009 (has links)
Estações de tratamento de água que tratam águas com cor elevada, causada pela presença de substâncias húmicas, e baixa turbidez têm apresentado problemas operacionais, principalmente na coagulação. As substâncias húmicas aquáticas (SHA) apresentam moléculas de massa molecular variada, grande parte entre 500 Da e 10 kDa. Por esse motivo, as condições de coagulação (tipo e dosagem de coagulante e pH de coagulação) podem ser totalmente distintas no tratamento de águas com a mesma coloração, devido à presença de SHA com propriedades estruturais diferentes, conforme já observado em pesquisas recentes. Neste contexto, o presente trabalho estudou a influência do tamanho molecular aparente das SHA na coagulação por hidroxicloreto de alumínio e fez a comparação dos custos entre este coagulante e dois estudados anteriormente - sulfato de alumínio e cloreto férrico - para mesma eficiência de remoção de cor. Para isso, realizaram-se ensaios de coagulação seguida de filtração em jarteste com quatro águas de estudo preparadas com frações de diferentes tamanhos moleculares aparentes de SHA, com cor verdadeira de 100 uH e turbidez de 5,0 uT. A partir dos resultados encontrados, pode-se afirmar que há influência do tamanho molecular aparente de diferentes frações de substâncias húmicas aquáticas na coagulação por hidroxicloreto de alumínio. Observou-se a tendência de maior consumo de coagulante para a coagulação de frações de SHA de menores tamanhos moleculares aparentes, em uma faixa determinada de pH. Em relação aos custos, o cloreto férrico foi o coagulante que apresentou menor valor para tratamento (por filtração direta) de águas com elevada cor aparente devida a presença de SHA. / The water treatment plants that treat waters with high brown color caused by the presence of humic substances, and low turbidity have been presenting operational problems, mostly in the coagulation. The aquatic humic substances (AHS) present molecules of different molecular mass, most part between 500 Da and 10 kDa. Therefore, the coagulation terms (coagulant type and dosage and coagulation pH) can be totally distinct in waters treatment with the same coloration, due to the presence of AHS with different structural properties, as already observed in recent researches. In this context, the present work presented the influence of AHS\'s apparent molecular size in the coagulation for aluminum hydroxychloride and did the costs comparison between this coagulant and two studied previously - aluminum sulfate and ferric chloride - for same efficiency of the color removal. For that, it accomplished coagulation rehearsals followed by filtration in jar-test with four waters of study prepared with fractions of different AHS\'s apparent molecular sizes, with true color of 100 uH and turbidity of 5.0 uT. From the found results, it can affirm that there is influence of the apparent molecular size of different fractions from aquatic humic substances in the coagulation for aluminum hydroxychloride. The larger coagulant consumption tendency was observed for the AHS\'s fractions coagulation of smaller apparent molecular sizes, in a range determined by pH. Regarding the costs, the ferric chloride was the coagulant that presented smaller value for treatment (for direct filtration) of waters with high brown apparent color due the presence of AHS.
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Tribunal penal internacional e o impacto com a ordem jurídica interna.Soares Neto, Edigardo Ferreira 03 September 2015 (has links)
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Previous issue date: 2015-09-03 / In this dissertation, it will be made an approach to the International Criminal Court (ICC) rules in comparison with those of the Brazilian legal system, what coincide, making a check analysis of possible antinomies between internal standard and internalized. In this north, will be carried out an assessment of International Courts historical evolution that existed and the Court of Rome predecessors forms, in addition to the perception of data relating to its creation and accession of Brazil for their rules. In sequence, the features Court are related and, in this line, individual criminal responsibility, own this approach, in addition to the reflection on the concept of the Statute Member States sovereignty. Then the study is concentrated on the examination of international criminal law in comparison with the international criminal law, where international cooperation is addressed, in addition to the core crimes and criminal principles common to the internal order and external, all under the rules paradigm for the protection of international human rights. Finally, it will be checked the apparent shocks between constitutional rules and the Rome Statute, a verification of compatibility, a control of all juridical convention on domestic law impact and effect. / Neste trabalho, far-se-á uma abordagem das normas do Tribunal Penal Internacional em comparação com as do ordenamento jurídico brasileiro, naquilo que coincidem, fazendo uma análise de verificação das possíveis antinomias entre a norma interna e a internalizada. Neste norte, será realizada uma apreciação da evolução histórica das Cortes Internacionais que existiram e foram antecessoras do Tribunal de Roma, além da percepção dos dados referentes à sua criação e adesão do Brasil as suas regras. Em sequência, as características da Corte serão relacionadas e, nesta linha, a responsabilidade penal individual, própria desta abordagem, além do reflexo no conceito de soberania dos Estados/Partes do Estatuto. Em seguida, o estudo é concentrado no exame do direito penal internacional em comparação com o direito internacional penal, onde a cooperação internacional é abordada, além dos core crimes e princípios penais comuns à ordem interna e externa, tudo sob o paradigma das regras de proteção aos direitos humanos internacionais. Por fim, checar-se-á os aparentes choques entre normas constitucionais e as do Estatuto de Roma, numa verificação de compatibilidade, num controle de convencionalidade do impacto e consequência ao direito interno.
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Plant-seed predator interactions – ecological and evolutionary aspectsÖstergård, Hannah January 2008 (has links)
<p>Plant-animal interactions are affected by both abundance and distribution of interacting species and the community context in which they occur. However, the relative importance of these factors is poorly known. I examined the effects of predator host range, environmental factors, host plant populations, plant traits and fruit abortion on the intensity of pre-dispersal seed predation in 46 host populations of the perennial herb <i>Lathyrus vernus</i>. I recorded damage by beetle pre-dispersal seed predators, mainly <i>Apion opeticum </i>and <i>Bruchus atomarius</i> with different host ranges on <i>L. vernus</i> as well as on two additional host plants. Local seed predator population size was mainly influenced by plant population size, current seed production and beetle population size in the previous year, but was not strongly affected by connectivity. The monophagous seed predator was less abundant and had lower densities than the oligophagous. Both predator species had a strong ability to track fluctuations in seed production; intensity of predation increased with relative increases in seed production. Oligophagous predation on<i> L. vernus i</i>ncreased with the abundance of alternative hosts, but presence of<i> L. vernus</i> did not affect predation on alternative hosts. Abundances and trait preferences differed among three co-occurring seed predators, but were also associated with the abundance of the other species. Overall, seed predation influenced selection on flower number. I found clear indications of seed predator offence but no obvious plant defence. The pattern of fruit abortion was associated with reduced plant fitness since the seed predator had an advanced ability to locate fruits with high probability of retention. Taken together, different factors influencing abundance of the seed predator species, different preferences, and context dependent trait selection are likely to result in complex spatio-temporal variation in overall seed losses and trait selection in the common host plant.</p>
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Plant-seed predator interactions – ecological and evolutionary aspectsÖstergård, Hannah January 2008 (has links)
Plant-animal interactions are affected by both abundance and distribution of interacting species and the community context in which they occur. However, the relative importance of these factors is poorly known. I examined the effects of predator host range, environmental factors, host plant populations, plant traits and fruit abortion on the intensity of pre-dispersal seed predation in 46 host populations of the perennial herb Lathyrus vernus. I recorded damage by beetle pre-dispersal seed predators, mainly Apion opeticum and Bruchus atomarius with different host ranges on L. vernus as well as on two additional host plants. Local seed predator population size was mainly influenced by plant population size, current seed production and beetle population size in the previous year, but was not strongly affected by connectivity. The monophagous seed predator was less abundant and had lower densities than the oligophagous. Both predator species had a strong ability to track fluctuations in seed production; intensity of predation increased with relative increases in seed production. Oligophagous predation on L. vernus increased with the abundance of alternative hosts, but presence of L. vernus did not affect predation on alternative hosts. Abundances and trait preferences differed among three co-occurring seed predators, but were also associated with the abundance of the other species. Overall, seed predation influenced selection on flower number. I found clear indications of seed predator offence but no obvious plant defence. The pattern of fruit abortion was associated with reduced plant fitness since the seed predator had an advanced ability to locate fruits with high probability of retention. Taken together, different factors influencing abundance of the seed predator species, different preferences, and context dependent trait selection are likely to result in complex spatio-temporal variation in overall seed losses and trait selection in the common host plant.
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Evaluation of a Miniaturized Rotating Disk Apparatus for In Vitro Dissolution Rate Measurements in Aqueous Media : Correlation of In Vitro Dissolution Rate with Apparent SolubilityPersson, Anita M. January 2010 (has links)
The general aim of this thesis was to evaluate a newly designed and constructed miniaturized rotating disk apparatus for in vitro dissolution rate measurements of different drug substances from all of the classes in the Biopharmaceutical Classification System (BCS). The new equipment is based on a low volume flow-through cell of Plexiglas, a gold plated magnetic bar and a special designed press. The disk of drug substance (approx. 5 mg) is placed eccentrically in the bar. Rotation speeds were set with a graded magnetic stirrer. An external HPLC pump delivered a continuous flow of aqueous medium to the flow-through cell during dissolution testing. A reversed phase high-performance liquid chromatography system using diode array detection (RP-HPLC-DAD) was coupled online to the new equipment. The injections from the miniaturized rotating disk outlet into the quantifying HPLC system were controlled by a six-position switching valve. The injection volumes from the valve and the autosampler, used for the external standards, were statistically evaluated to match each other volumetrically. No analyses were longer than three minutes, using isocratic mode. A traditional USP rotating disk apparatus was used as a reference system and the two instruments were shown to be statistically dissimilar in the numerical dissolution rate values probably due to different hydrodynamics, but had approximately the same precision/repeatability. When correlating the logarithmic values of the in vitro dissolution rate (G) with the apparent solubility (S), using shake-flask methodology in the solubility studies, the two apparatuses gave the same correlation patterns. Further correlation studies were done where the media components were altered by the use of different buffer species or additives into the buffers, such as inorganic salts. Chemometric tools, e.g. orthogonal partial least squares (OPLS), were used to better evaluate the most influential factors for G and S in different media. The most significant factor for a model basic drug substance (terfenadine) was pH, followed by the ionic strength (I) and added sodium chloride in one of the media. However, the surfactants in the Fasted State Simulated Intestinal Fluid (FaSSIF-V2) were found to be insignificant for G and S in this study (using a 95% confidence interval). The new miniaturized apparatus is a promising prototype for in vitro dissolution rate measurements both for early screening purposes and in dissolution testing during drug development, but needs further instrumental improvements.
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Seismic response control of structures using novel adaptive passive and semi-active variable stiffness and negative stiffness devicesPasala, Dharma Theja 16 September 2013 (has links)
Current seismic design practice promotes inelastic response in order to reduce the design forces. By allowing the structure to yield while increasing the ductility of the structure, the global forces can be kept within the limited bounds dictated by the yield strength. However, during severe earthquakes, the structures undergo significant inelastic deformations leading to stiffness and strength degradation, increased interstory drifts, and damage with residual drift. The research presented in this thesis has three components that seek to address these challenges.
To prevent the inelastic effects observed in yielding systems, a new concept “apparent weakening” is proposed and verified through shake table studies in this thesis. “Apparent weakening” is introduced in the structural system using a complementary “adaptive negative stiffness device” (NSD) that mimics "yielding” of the global system thus attracting it away from the main structural system. Unlike the concept of weakening and damping, where the main structural system strength is reduced, the new system does not alter the original structural system, but produces effects compatible with an early yielding. Response reduction using NSD is achieved in a two step sequence. First the NSD, which is capable of exhibiting nonlinear elastic stiffness, is developed based on the properties of the structure. This NSD is added to the structure resulting in reduction of the stiffness of the structure and NSD assembly
or “apparent weakening”-thereby resulting in the reduction of the base shear of the assembly. Then a passive damper, designed for the assembly to reduce the displacements that are caused due to the “apparent weakening”, is added to the structure-thereby reducing the base shear, acceleration and displacement in a two step process.
The primary focus of this thesis is to analyze and experimentally verify the response reduction attributes of NSD in (a) elastic structural systems (b) yielding systems and (3) multistory structures. Experimental studies on 1:3 scale three-story frame structure have confirmed that consistent reductions in displacements, accelerations
and base shear can be achieved in an elastic structure and bilinear inelastic structure by adding the NSD and viscous fluid damper. It has also been demonstrated that the stiffening in NSD will prevent the structure from collapsing. Analogous to the inelastic design, the acceleration and base shear and deformation of the structure
and NSD assembly can be reduced by more than 20% for moderate ground motions and the collapse of structure can be prevented for severe ground motions.
Simulation studies have been carried on an inelastic multistoried shear building
to demonstrate the effectiveness of placing NSDs and dampers at multiple locations along the height of the building; referred to as “distributed isolation”. The results reported in this study have demonstrated that by placing a NSD in a particular story the superstructure above that story can be isolated from the effects of ground motion. Since the NSDs in the bottom floors will undergo large deformations, a generalized scheme to incorporate NSDs with different force deformation behavior in each storey is proposed. The properties of NSD are varied to minimize the localized inter-story deformation and distribute it evenly along the height of the building. Additionally, two semi-active approaches have also been proposed to improve the performance of NSD in yielding structures and also adapt to varying structure properties in real time.
The second component of this thesis deals with development of a novel device to control the response of structural system using adaptive length pendulum smart tuned mass damper (ALP-STMD). A mechanism to achieve the variable pendulum length is developed using shape memory alloy wire actuator. ALP-STMD acts as a
vibration absorber and since the length is tuned to match the instantaneous frequency, using a STFT algorithm, all the vibrations pertaining to the dominant frequency are absorbed. ALP-STMD is capable of absorbing all the energy pertaining to the tuned-frequency of the system; the performance is experimentally verified for forced vibration (stationary and non-stationary) and free vibration.
The third component of this thesis covers the development of an adaptive control algorithm to compensate hysteresis in hysteretic systems. Hysteretic system with variable stiffness hysteresis is represented as a quasi-linear parameter varying (LPV) system and a gain scheduled controller is designed for the quasi-LPV system using linear matrix inequalities approach. Designed controller is scheduled based on two parameters: linear time-varying stiffness (slow varying parameter) and the stiffness of friction hysteresis (fast varying parameter). The effectiveness of the proposed
controller is demonstrated through numerical studies by comparing the proposed controller with fixed robust H∞ controller. Superior tracking performance of the LPV-GS
over the robust H∞ controller in different displacement ranges and various stiffness switching cases is clearly evident from the results presented in this thesis. The LPV-GS controller is capable of adapting to the parameter changes and is effective over the entire range of parameter variations.
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Des interactions indirectes entre les proies : modélisation et influence du comportement du prédateur communTeixeira Alves, Mickael 25 January 2013 (has links) (PDF)
Cette thèse a pour objet la modélisation de systèmes multi-proies-prédateurs. Elle s'intéresse particulièrement à l'influence du comportement d'un prédateur sur les interactions indirectes entre ses proies, i.e. l'effet de l'ajout d'une proie sur la densité des autres. La théorie classique prédit l'occurrence d'effets indirects négatifs entre les proies, ou compétition apparente, résultant de l'interaction avec un prédateur commun ; des résultats plus récents identifient certains mécanismes à même d'atténuer ces effets négatifs. Nos travaux revisitent les hypothèses autour de ces mécanismes dans des systèmes composés de deux proies et de leur prédateur commun. Après avoir fixé le cadre écologique en rappelant les principaux types d'interactions directes et indirectes, nous introduisons les modèles proies-prédateurs classiques. Les travaux se concentrent ensuite sur une famille de modèles présentant de la densité-dépendance négative chez les prédateurs couplés à différentes modélisations du comportement des prédateurs lorsqu'ils sont confrontés à plusieurs types de proies. Nous montrons notamment que les interactions entre ces mécanismes peuvent inverser la compétition apparente et, contre intuitivement, accroître la densité des proies par l'intermédiaire d'un prédateur commun. Nos résultats trouvent pour partie application en lutte biologique, où il est courant de chercher à favoriser les auxiliaires en aménageant leur environnement (apport de nourriture alternative, refuge, ...). Ils suggèrent que de telles pratiques peuvent se révéler contre-productives, le contrôle des ravageurs pouvant être affaibli du fait d'une distraction de leurs prédateurs.
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Micro-PIV Study Of Apparent Slip Of Water On Hydrophobic SurfacesAsthana, Ashish 01 July 2008 (has links)
The condition of no relative velocity of fluid past solid is termed as ‘no-slip boundary condition’. This condition is a general observation in fluid mechanics. However, several research groups have recently reported slip of water for surfaces with water repelling chemistry (referred to as hydrophobic surfaces). The effect has been attributed to disruption of H-bonding network of water molecules at such surfaces and resulting nucleation of dissolved gases and even reduced water density locally in absence of dissolved air. Slip of water on hydrophobic surfaces has been demonstrated to get amplified by high degree of roughness and patterning. Trapping of air in the surface asperities has been cited as the possible reason. The present work focuses on the study of effect of surface chemistry and roughness on flow behavior close to solid surfaces.
Superhydrophobic surfaces have been generated by novel methods and wet-etching has been used to generate well-defined patterns on silicon surfaces. For flow characterisation, a micrometre resolution Particle Image Velocimetry (micro-PIV) facility has been developed and flow measurements have been carried out with a spatial resolution of less than 4 µm.
It has been found from the experiments that flow of water on smooth surfaces, with or without chemical modification, conforms to the no-slip within the resolution limits of experiments. Deviation is observed in case of rough and patterned hydrophobic surfaces, possibly because of trapped air in asperities. Total Internal Reflection experiments, used to visualise the air pockets, confirmed the trapping of air at asperities. Diffusion of air out of the crevices seems to be the limiting factor for the utility of these surfaces in under-water applications.
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