This study developed a microfluidic flow sensor for the detections of velocity and viscosity, especially for ultra-low viscosity detection. An etched optic fiber with the diameter of 9 £gm is embedded in a microfluidic chip to couple green laser light into the microfluidic channel. The flow induced vibration causes periodic flapping motion of the optic fiber cantilever because of the pressure difference from two sides of fiber cantilever. Through the frequency analysis, the fluidic properties including the flow rate and the viscosity can be detected and identified. Results show that this developed sensor is capable of sensing liquid samples with the flow rates from 0.17 m/s to 68.81 m/s and the viscosities from 0.306 cP to 1.200 cP. In addition, air samples (0.0183 cP) with various flow rates can also be detected using the developed sensor. Although the detectable range for flow rate sensing is not wide, the sensitivity is high of up to around 3.667 mm/(s¡EHz) in test liquid in DI water, and when detecting air the sensitivity is 6.190 mm/(s¡EHz). The developed flow sensor provides a simple and straight forward method for sensing flow characteristics in a microfluidic channel.

The goal of this research is to measure viscosity via the analysis of amplitude response of a piezo driven vibrating cantilevers partially immersed in a viscous medium. As a driving frequency is applied to a piezoceramic material, the external forces acting on the system will affect its maximum amplitude. This thesis applies this principle through experimental and analytical analyses of the proportional relationship between viscosity and the amplitude response of the first natural frequency mode of the sinusoidal vibration. Currently, the few cantilever-based viscometer designs that exist employ resonant frequency response as the parameter by which the viscosity is correlated. The proposed piezoelectric viscometer employs amplitude response in lieu of resonant frequency response. The goal of this aspect of the research was to provide data confirming amplitude response as a viable method for determining viscosity. A miniature piezoelectric plate was mounted to a small stainless-steel cantilever beam. The tip of the cantilever was immersed within various fluid test samples. The cantilever was then swept through a range of frequencies in which the first frequency mode resided. The operating principle being as the viscosity of the fluid increases the amplitude response of cantilever vibration will decrease relatively. What was found was in fact an inversely exponential relationship between dynamic viscosity and the cantilever beam's vibrational amplitude response. The experiment was performed using three types of cantilevers as to experimentally test the sensitivity of each.

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Plastics are highly useful economically because of their resistance to diverse types of environmental and chemical agents and their ability to be molded into many types of products. Globally, plastic production is greater than 20 million metric tons per year. However, their widespread use and often their disposable nature results in significant plastic accumulation in the environment. Plastics are made of hydrocarbons, materials that are biodegradable depending on their molecular structure and size. It is hypothesized that pre-treatment of plastic materials could enhance their bioavailability, facilitating their microbial biodegradation. In this dissertation, a process was developed to treat nylon 6,6 polymers by acid hydrolysis to produce a microbial growth medium. The chemical composition of the medium was determined by low pressure liquid chromatography-spectrophotometry and electrospray ionization mass spectrometry and found that the medium was a mixture of molecules with molecular weight > 800 m/z and with similar chemical characteristics to polyamines. There was steady growth of Pseudomonas putida KT2440 in the medium with concomitant substrate biodegradation. Notably, the yeast Yarowia lipolytica grew well in the medium when supplemented with yeast extract. A similar medium derived from nylon 6,6 containing nylon-derived particles supported the growth of Beijerinckia sp. and Streptomyces sp. BAS1. Confocal laser scanning microscopy and flame ionization gas chromatography were used to identify and quantify the production of polyhydroxybutyrate, a type of “bioplastic”. The aforementioned microorganisms were cultivated in a bench-scale bioreactor that was developed as part of this dissertation. The bioreactor had a novel impeller design resulting in enhanced mixing and rotation and also a modular format allowing for diverse configurations. The bioreactor was notable for its durability and low cost. A detailed description of its design is included in the appendices. In summary, plastic materials can potentially be processed into growth media for microorganisms and can be used for production of value-added products. The media described herein can be used in bioconversion processes using a bioreactor.

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Foam is one of the most frequently used multiphase fluids in underbalanced drilling operations because of its high carrying capacity of cuttings, compressibility property, formation fluid influx handling, etc. Foam rheology has been studied for many years. Researchers tried to explain foam behaviour by using conventional methods, i.e., determining rheological parameters of pre-defined rheological models like Power law, Bingham Plastic etc., as a function of gas ratio. However, it is known that bubble size and texture of the foam is also effective on foam behaviour. When foam is generated by using different foaming agents, even if the gas ratio is constant, different rheological parameters are observed. Therefore a more general foam characterization method that uses the bubble size and texture of foam is required. Improvements on image analysis, and computer technology allow monitoring the bubble size and texture of foam bubbles. A more comprehensive model of foam rheology definition in which the bubble size, and texture effects of the foam body is developed. Three different analysis methodologies are introduced / i) Generalized volume equalized approach, ii) Generalized volume equalized approach and image processing data, and iii) Image processing data only. The necessary information including the rheological information and image data is acquired from the experimental set-up developed for this study. It has been observed that, the pressure losses could be predicted as a function of bubble size, circularity and general rheological parameters, in &amp / #61617 / 20 % certainty limit. It is also observed that using only the image information is possible to characterize the foam in an accurate and fast manner.

The addition of coarse particles to a flocculating fine particle slurry increases the Bingham yield stress of the resulting mixture, which can drastically alter the laminar-to-turbulent transition velocity. The objective of this study is to quantify the effect of coarse particle size and volume concentration on mixture rheology. Fine particle (kaolin) mixtures of 10% to 22% (by volume) were prepared, to which sand particles were added to provide a coarse solid concentration of 5% to 20% (by volume). Sand particles of two different sizes – 90 and 190 microns – were added and these kaolin-sand-water mixtures tested with a concentric cylinder viscometer. At higher total solids concentrations, the Bingham yield stress of the bimodal mixture can increase by as much as 80% over that of a kaolin-only slurry. Coarse particle diameter had little effect. This study demonstrates that the use of existing correlations should be eschewed. System-specific high-quality measurements are necessary. / Chemical Engineering

Cartilage tissue provides compressive resistance in diarthrodial joints, and has been shown to be regulated by mechanical signals, in particular with regard to production of extracellular matrix proteins. However, less is understood about how chondrocytes in regions not solely purposed to provide compressive resistance may also be affected by mechanical forces. The growth plate is a small layer of cartilage that functions to facilitate longitudinal growth of the long bones from in utero through post-adolescent development. The growth plate maintains distinct regions of chondrocytes at carefully regulated stages of endochondral ossification that are in part characterized by their morphology and differential responsiveness to vitamin D metabolites. Understanding if mechanical cues could be harnessed to accelerate or delay the process of endochondral ossification might be beneficial for optimizing tissue engineering of cartilage or osteochondral interfaces. This study focused on three aims to provide a basis for future work in this area: 1) Develop a cell line culture model useful for studying growth plate chondrocytes, 2) Determine the response of primary growth plate chondrocytes and the cell line model to fluid shear stress, and 3) determine if expression of integrin beta 1 is important for the observed responses to shear stress. The findings of this study suggest that inorganic phosphate can promote differentiation in coordination with the 24,25(OH)2D3 metabolite of vitamin D, and that fluid shear stress generally inhibits differentiation and proliferation of growth plate chondrocytes in part through an integrin beta 1 mediated pathway.

La connaissance de la viscosité est un défi majeur dans les technologies de pointe (biomédical, pétrochimie, imprimerie, cosmétique, agroalimentaire, etc). Cette étude présente un capteur de viscosité qui exploite la vibration transversale forcée d’une poutre mince. L’amortissement induit par le fluide permet d’évaluer sa viscosité et sa masse volumique par la seule connaissance des caractéristiques à la résonance de la poutre (amplitude et fréquence). Cette mesure est réalisée par un circuit électromagnétique. Dans ce travail, la simulation numérique et l’étude expérimentale du viscosimètre sont réalisées en vue de mieux cerner les paramètres influençant le fonctionnement du capteur. Les différentes investigations menées dans ce travail sont d’une grande importance pour l’optimisation du viscosimètre d’une part. D’autre part, c’est une contribution à l’ensemble des études qui traitent de l’aspect du couplage fluide-structure-électromagnétisme. / Knowing the viscosity becomes increasingly a major challenge in leading-edge technologies (biomedical, petrochemical, printing, cosmetic, food industry, etc). This study presents a viscosity sensor based on a thin beam immersed in a newtonian fluid and subjected to transverse vibrations due to an electromechanical excitation system. The damped vibration can be used to evaluate the fluid viscosity and density by measuring the beam’s resonance characteristics (amplitude, frequency). This measurement is done by an electromagnetic feedback circuit. In this work, numerical model and experimental studies of the vibrating viscometer are conducted to better understand the influencing factors of the sensor’s operation. The different investigations carried out in this work are of great importance for the viscometer optimization on one hand. On the other hand, it’s a contribution to all studies dealing with the aspect of fluid-structure-electromagnetism coupling.