A simple, but innovative microfluidic Lab-on-a-chip (LOC) device which is broadly applicable in point of care diagnostics of biological pathogens was designed, fabricated and assembled utilising explicit microfluidic techniques. The purpose of this design was to develop a cartridge with the capability to perform multiplex DNA amplification reactions on a single device. To achieve this outcome, conventional laboratory protocols for sample preparation; involving DNA extraction, purification and elution were miniaturized to suit this lab-on-a-chip device of 75mm X 50mm cross-sectional area. The extraction process was carried out in a uniquely designed microchamber embedded with chitosan membrane that binds DNA at pH 5.0 and elutes when a different solution at pH 9.0 flows through. Likewise, purification protocol that occurs in the designed waste reservoir is very significant in biomedical field because it is concerned with waste treatment and cartridge disposability, was performed with a super absorbent powder that converts liquid to a gel like substance. This powder is known as sodium polyacrylate, which is also they treated with anti-bacterial chemicals to prevent environmental contamination. Furthermore, this process also employed the use of a passive valve for a precise fluid handling operation involving flow regulation from extraction to waste reservoir. In order to achieve the intended multiplexing function a multiplexer was created to distribute flow simultaneously through a bifurcated network of channels connected to six similar amplification microchambers. Prior to fabrication, computational fluid dynamics (CFD) simulation was utilized at flowrates less than 10μL/s as the means to test the effectiveness of each design components and also to specifically deduct empirical values that can be analyzed to improve or understand the relationship between the fluid and geometrical constraints of the microfluidic modular elements. The device produced was a hybrid cartridge composed of PDMS and glass which is the most widely used materials microfluidics research due to their low cost and simplicity of fabrication by soft lithography technique. The choice of material also took into account the various physical and chemical properties advantages and disadvantages in their bio-medical applications. Such properties include but not limited to surface energy that determines the wetting fluid characteristics, biocompatibility, optical transparency. Subsequently, after a prototype cartridge was developed fluid flow experimentation using liquid coloured dye was used on the fully fabricated cartridge to test the efficacy of its microfluidic functionalities before expensive DNA amplification reagents were utilised at similar flowrates to the CFD simulations. This gave rise to comparison between similar and dissimilar flow Peculiarities in the microfluidic circuit of both experiments. The final experiment was performed with the aid of a recent molecular technique in DNA amplification known as of RPA kit (recombinase polymerase amplification reaction). It involved performing two main reaction experiments; first, was the positive experiment that bears the sample DNA and the latter, negative that served as the control without DNA. In the end, quantitative analysis of results was done using an agarose gel that showed 143 base pairs, for the positive samples, thus validating the amplification experiment.

The structural response of unreinforced masonry elements strengthened with hybrid elastomeric/fiber materials was investigated through material characterization and flexural experiments. Material characterization tests were performed on various unreinforced and reinforced elastomeric materials to identify those materials that were best suited for use as structural retrofits. After material characterization was completed, the three most promising material systems were selected for further investigation, including one unreinforced elastomer film and two reinforced elastomer films with fiber orientations at 0/90° and +/- 45° relative to the major axis of the masonry elements. A series of four-point bending tests were performed on the selected masonry and epoxy bonded elastomer/fiber hybrid retrofits to determine the structural response of the composite systems. The experimental load-deformation response was used, along with material characterization results, in the development of a semi-empirical model to predict the static moment capacity of the strengthened masonry system. This model will be used in the development of reliable design criteria for masonry walls strengthened with these advanced materials.

Η μελέτη της δυνατότητας αποθήκευσης ενέργειας σε σύνθετα συστήματα ελαστομερικής μήτρας με ενσωματωμένα ανόργανα νανοεγκλείσματα, παρουσιάζει μεγάλο ενδιαφέρον τόσο από τη πλευρά της έρευνας όσο και από τη πλευρά των εφαρμογών. Η μεγάλη τους ανάπτυξη οφείλεται, κυρίως, στην ηλεκτρική συμπεριφορά που παρουσιάζεται σε εναλλασσόμενο πεδίο αλλά και στο ευρύ φάσμα εφαρμογών που περιλαμβάνει τις δομικές και μηχανικές εφαρμογές, τις ηλεκτρικές και ηλεκτρονικές εφαρμογές και τέλος εφαρμογές σε πεδία όπως η οπτική, οπτοηλεκτρονική, βίο- νανοτεχνολογία και σε διατάξεις αποθήκευσης ενέργειας. Στο πρώτο μέρος της διπλωματικής εργασίας παρουσιάζονται οι βασικές αρχές που αφορούν τα σύνθετα υλικά, τη θεωρία των διηλεκτρικών, την ηλεκτρική απόκριση σύνθετων υλικών με ελαστομερική μήτρα και τις μεθόδους αποθήκευσης ενέργειας σε τέτοια συστήματα. Στο δεύτερο μέρος εξετάζεται η διηλεκτρική απόκριση ελαστομερικών σύνθετων υλικών με ενσωματωμένα νανοσωματίδια στρωματικά άλατα πυριτίου και η δυνατότητα αποθήκευσης ενέργειας μέσω της συνάρτησης πυκνότητας ενέργειας. / The study of the energy storage efficiency in elastomeric matrix composites with embedded inorganic nano-inclusions, presents an increasing interest not only from the research point of view, but also from the technological applications side. Their increased development is mainly ought to their electric behavior, under the influence of an alternating field, but also to a wide range of applications, which include structural and mechanical applications, electric and electronic applications and finally, applications in fields such as optical, optoelectrical, and bio-nanotechnology. At the first part of this final project basic issues concerning composite materials, the theory of dielectrics, electric response of composites materials in a elastomeric matrix, and the methods of energy storing at the examined systems are presented. In the second part, the dielectric response of elastomeric composites with embedded layered silicates nanoinclusions is investigated. Finally, the energy storage efficiency of the nanocomposites is examined via the density of energy.

This thesis focuses on the experimental studies conducted on the development of low-cost seismic base isolation pads using scrap automobile tires. Seismic base isolation is a well-defined building protection system against earthquakes, on which numerous studies have been conducted. The majority of the previous studies focus on the performance improvement of the base isolation systems. However, this study aims at cost and weight reduction of seismic base isolation pads by recycling otherwise useless material: scrap tires. Elastomer-based isolators have been heavily studied and used for the last 25 years. Steel or fiber reinforcement inside the elastomer isolators provides high vertical stiffness, whereas rubber segments between reinforcement layers provide low horizontal stiffness for the seismic base isolation. Since 1960&rsquo / s, automobile tires have been produced by means of vulcanizing rubber with steel mesh in different forms which have a similar effect as the steel plates or fibers inside the conventional elastomer-based isolators. Therefore, rectangular shaped layers cut from tread sections of used tires and then piled on top of each other can function as an elastomeric bearing. Since the tires are being designed for friction, load transfer between scrap tire layers would be large enough to keep all layers intact. A minimal slip generated between the piled layers at high strain rates may even help to dissipate some extra energy. Axial compression, dynamic free vibration, static shear and shaking table tests have been conducted on Scrap Tire Pads (STP) prepared by using different tire brands for different number of layers and orientations. The results have shown that the average shear modulus of STPs change between 0.9MPa and 1.85MPa. At the end of the dynamic tests it has been noticed that the lateral stiffness of STPs can be simply adjusted by changing the number of tread layers placed on top of each other. The amount of wire mesh inside the tire tread layers is relatively low compared to the steel plates in regular elastomeric pads / consequently, axial load capacity of STPs has been found to be around 8.0MPa. Static large deformation shear experiments have been performed to obtain the horizontal stiffness and shear modulus values at high strains and the results are tabulated in the manuscript. Steel and rubber layers are produced separately and just put on top of each other without any adhesive to form the &frac14 / scaled versions of STPs which were used to isolate a &frac14 / scaled masonry house on the shaking table available in METU Structural Laboratory. The experiment showed that non-vulcanized rubber-steel layers put on top of each other can also be used to isolate structures. In conclusion, STPs may be used as a low-cost alternative to conventional elastomer-based pads for seismic isolation of massive structures (e.g. stone wall rural masonry) or for temperature induced deformation compensation of rural bridges. STP usage is demonstrated using three hypothetical design examples in the manuscript.

Wave energy generation is a promising renewable energy source but it faces certain challenges before it can become commercially viable. In comparison to conventional energy generation it is expensive, furthermore it has been plagued by reliability challenges due to the harsh operating demands of the marine environment. This Thesis investigates the reliability of wave energy devices, and specifically focuses on mooring system reliability. Two major themes are developed: Firstly, an assessment is conducted on a conventional mooring component, reviewing safety factors suggested in mooring system design guidelines and investigating whether there is a potential to reduce these safety factors (and in so doing, reduce system costs). Numerical modelling, laboratory testing and field testing demonstrate that excessively large safety factors are published in design guidance for static loading scenarios. However, when considering fatigue loading regimes (a critical aspect of wave energy generation), the proposed safety factors are found to be appropriate. In fatigue design, the importance of selecting an appropriate stress concentration factor for use with generic S-N curves is highlighted. These findings indicate the publication of additional stress concentration factors and a standard approach for mean stress adjustment would be a valuable addition to mooring system design guidance for fatigue. The second theme introduces a novel mooring component, The Exeter Tether, designed to reduce mooring loads and thus reduce system costs. The introduction of any novel technology brings new reliability considerations, and a reliability assessment of the tether and sub-components is presented in this Thesis. Following a failure modes and effects analysis, a bespoke range of physical tests is developed to investigate reliability concerns unique to this novel component. Laboratory testing of the tether assembly shows promising fatigue performance, however field trials highlight concerns regarding bio-fouling and marine debris ingress. Sub-component testing of the EPDM (Ethylene propylene diene monomer) polymer core suggests an increase in material stiffness with both marine ageing and repeated compression cycles. This finding supports results from assembly trials in the laboratory and at sea, where tether assembly dynamic axial stiffness is observed to increase over time. The overarching design philosophy behind the Exeter Tether is to reduce mooring system loads, so establishing the `worked' operating profile of the tether is crucial for the design intentions to be realised without compromising the reliability of the overall mooring system. Trials on the anti-friction membrane establish optimum performance when using two layers of UHMWPE (Ultra high molecular weight polyethylene) tape. Further areas requiring research are highlighted, and suggestions are made to improve the reliability of future design iterations of The Exeter Tether. The two reliability approaches presented demonstrate the potential for cost reduction in mooring system design and highlight the importance of physical component testing, both in the field and in laboratory conditions, to optimise component design whilst ensuring overall system reliability.

Devido a forte concorrência dentro do mercado automobilístico, aspectos como qualidade e custo tornam-se prioritários na busca de competitividade. Diversas empresas trabalham em propostas visando a redução de custo sem perda de qualidade. Diversos veículos dentro do mercado brasileiro usam o coxim hidráulico no sistema de apoio do motor. A proposta inicial visa substituição deste coxim por um coxim elastomérico. Seguindo esta proposta, tem-se esta pesquisa que visa apresentar comparativamente o comportamento entre o coxim hidráulico e o coxim elastomérico. Além da revisão bibliográfica, realizamos o estudo comparativo experimental com peças físicas avaliadas conforme especificações utilizadas pela indústria automobilística. Observamos que o coxim elastomérico apresentou substancial melhoria desde os anos 70, oferecendo bom compromisso entre rigidez estática e isolação de vibração. O coxim hidráulico, por sua vez, apresenta alto amortecimento na faixa de baixa freqüência e sua rigidez dinâmica ainda é maior na faixa de alta freqüência, porém seu desempenho quanto a isolação de vibração irá depender da rigidez dinâmica, da constante de amortecimento e da faixa de freqüência em estará submetido. Devido ao custo do coxim elastomérico ser cerca de três vezes menor que o custo do coxim hidráulico, o mesmo torna-se grande atrativo para compor o sistema de apoio do motor. Ainda acrescentamos que se deve avaliar o veículo como um todo em laboratórios especializados para avaliação do desempenho quanto ao conforto do usuário. / Due to strong competition inside of the automotive market, aspects as quality and cost become priority in the search of competitiveness. Several companies work in proposals seeking the cost reduction without quality loss. Several vehicles inside of Brazilian market use the hydraulic mount at their engine mount system. The initial proposal seeks the substitution of this type of mount by an elastomeric mount. Based on this proposal, we have this research that intends to present comparatively the behavior between the hydraulic mount and the elastomeric mount. Besides the researched bibliography, we accomplished the practical comparative study with physical parts evaluating as specifications used by automotive industries. We observed that the elastomeric mount presented substantial improvements since the seventies, offering good compromising between static stiffness and isolation vibration performance. The hydraulic mount presents high damping at low frequency range but its dynamic stiffness at high frequency is larger than elastomeric mount, but its performance at vibration isolation will depend of dynamic stiffness, damping coefficient and of the frequency range that it will be submitted. Due to the cost of the elastomeric mount to be about three times smaller than hydraulic mount cost, the elastomeric mount becomes great attraction to compose the engine mount system. Besides the cost, is evident that should be also evaluate the performance for the users comfort and new studies in specialized laboratories shall be accomplished.

Os elásticos corrente estão presentes na ortodontia desde o início do século XX, e devido a sua importância na biomecânica ortodôntica a indústria vem aperfeiçoando suas propriedades. O objetivo dessa pesquisa foi avaliar o remanescente de força, a deformação plástica e a embebição dos elásticos corrente ortodônticos, imersos em água destilada, durante um período de 4 semanas. Neste estudo foram selecionados elásticos corrente de 5 modelos comerciais, divididos em 2 grupos (100gf e 300gf), sendo que em cada grupo foi gerado 12 corpos de prova produzindo um total de 24 corpos de cada modelo comercial, totalizando 120 corpos de prova de elásticos corrente ortodônticos de quatro marcas comerciais ( American Orthodontics, Rocky Mountain, 3M Unitek e Morelli). Os elásticos corrente foram cortados padronizandoos em 6 módulos, pesados e medidos, e foram submetidos a um teste estático por um período de 4 semanas. Durante o teste, os elásticos foram armazenados em água destilada à 37ºC e estirados no simulador oral em distâncias que representavam 100gf ou 300gf. O remanescente de força foi mensurado em 6 intervalos de tempo (1 hora, 24 horas, 1 semana, 2 semanas, 3 semanas e 4 semanas) em uma balança digital modificada. Ao final da mensuração da quarta semana os elásticos foram retirados da balança modificada e, foram levemente secos em papel toalha e pesados individualmente em uma balança analítica. Em seguida foram medidos novamente utilizando um paquímetro digital. Para analisar os dados obtidos do remanescente de força, embebição e deformação plástica, foram realizadas análises de variância (ANOVA), e teste de Tukey (p<0,05) para identificar as diferenças entre os grupos. A carga inicial (100 e 300gf) foi estatisticamente significante no remanescente de força (p<0,05) e para o fenômeno da embebição não significante (p>0,05). Os elásticos da empresa 3M Unitek apresentaram os menores remanescentes de força e foram estatisticamente diferentes dos demais elásticos (p<0,05). Houve uma correlação moderada com (r=0,68) e p=0,03 indicando que quanto maior o ganho de massa (maior embebição), menor o remanescente de força. / The elastomeric chain (EC) are present in orthodontics since the beggining of the XX century, and due to its fundamental importance in orthodontic biomechanic, the industry has been perfecting it\'s properties and many studies have been done to understand them better. The objective of this research was to evaluate the remaining force, the plastic deformation and the sorption of the orthodontic EC, submerged in distilled water, during a period of 4 weeks. In this study 5 elastomeric chain commercial models were selected, divided in two groups (100gf and 300gf), and from each group 12 specimen were generated producing a total of 24 specimen of each commercial model. Totalizing 120 specimen of orthodontic EC of four commercial brands (American Orthodontics, Rocky Mountain, 3M Unitek and Morelli). For this study an oral simulator device was developed for activation of EC. EC were cut standardizing them in 6 modules, weighted and measured, and were submitted to a static test for a a period of 4 weeks. During the test, EC were stored in distilled water at 37ºC and stretched in distances that represented 100gf or 300gf. The remaining force was measured in 6 time intervals (1 hour, 24 hours, 1 week, 2 weeks, 3 weeks and 4 weeks) in a modified digital scale. At the end of the measurement of the fourth week the elastics were removed from the modified scale and were dried slightly in paper towel and weighted individually in an analytic scale. Next, they were measured again using a digital pachymeter. To analyze the data obtained of the remaining force, soaking and plastic deformation, variance analysis (ANOVA) and Tukey test (p<0,05) were performed to identify the differences between groups. The initial load (100 and 300gf) was statistically significant on remaining force (p<0,05), and for the soaking phenomenon non significant (p>0.05). EC of the 3M Unitek company presented the smallest remaining force.l and were statistically different from the other elastics (p<0,05). There was a moderate correlations with (r=0,68) and p=0,03 indicating that the bigger the weight gain (more soaking), the smaller the remaining force.

Orientador: Inez Valeria Pagotto Yoshida / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T13:38:50Z (GMT). No. of bitstreams: 1 PachecoeSilva_Viviane_M.pdf: 4530394 bytes, checksum: 571677ec4e372aa12989ee8eada906a1 (MD5) Previous issue date: 2005 / Mestrado / Quimica Inorganica / Mestre em Química

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