published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

An adaptive wing, a zero mass ux ow control device for low speed airfoil separation control, is investigated both experimentally and computationally at low speeds. The adaptive mechanism in the wings provides variable camber that can be actuated across a range of frequencies and amplitudes. Piezoelectric actuators are housed in a NACA 4415 airfoil with a chord length of :203 m. The entire adaptive wing assembly is then wrapped under a layer of latex membrane to provide a exible and smooth upper surface pro le. Experimental diagnostics include ow visualization, particle image velocimetry, as well as lift and drag measurements. The numerical simulation uses a 2D incompressible CFD code based on a nite-volume structured formulation with a chimera overset grid for the purpose of parallel computing. In the current study, the dimensionless speed range examined is 2:5 104 Re 1:5 105, where particular focus is given to Re 7:5 104, where Re = U` . All experiments and simulations are conducted in the range of attack angles from 0 24 and between reduced frequency values from 0 f+ 1:09, where f+ = f` U1 . Both experimental and computational results show that the region of separation is reduced when the actuation is turned on, thus enhancing aerodynamic e ciency. The maximum coe cient of lift increases by 26% when the reduced frequency, f+, is approximately :2, where the ow control mechanism appears to be most e ective. Phase-locked PIV and CFD vorticity plots reveal that the downward motion of the surface actuation decelerates the boundary ow and increases surface pressure, resulting in the formation of a series of cross-stream vortices that provides uid entrainment towards the suction surface, hence reducing separation.

This dissertation serves to study a protein's conformation-function relationship since immobilized proteins often behave differently from their solution-state counterparts. Therefore, this study is important to the application of protein-based biodevices. Another aim of this dissertation is to explore a new approach to realize low voltage electrowetting without the help of oil bath. Utilizing this approach, a protein micro-separation was realized. Additionally, the interfacial properties of ionic liquid (IL) solid-like layer, which played a key role in electrowetting, was studied for further developments of IL-based applications. Atomic Force Microscopy (AFM) was utilized in the study and played multiple roles in this dissertation. First, AFM was used as a fabrication tool. In the contact mode, conductive AFM tip was used to conduct the electrochemical oxidation to create a chemical pattern or to conduct an electrowetting experiment. Subsequently, AFM was used as a characterization tool in the tapping mode to characterize the surface structure, the thickness, and the surface potential. Furthermore, AFM in the contact mode was used as a measurement tool to measure the tribological force properties of sample. The results of the study concerning the conformational change in immobilized calmodulin showed that the immobilized CaM retained its activity. Additionally, the immobilization of CaM on a solid support did not interfere with the ability of the protein to bind calcium, as well as CaM kinase binding domain. For the electrowetting experiment, our data suggested that the ultra-high capacitance density of the IL dielectric layer leads to the low voltage electrowetting. We also successfully demonstrated the streptavidin and GFP proteins separation by Electrowetting-on-Dielectric (EWOD) force. The results of the surface properties study indicated that the charge and dipole of the substrate can influence the structures and properties of the IL interfacial layer. Our study would be beneficial in research and assay work involving engineered proteins, as well as the study and development of electrowetting applications.

Pulsed plasma jets (also called "SparkJets'") were investigated for use in controlling the mean separation location induced by shock wave-boundary layer interaction. These synthetic jet actuators are driven by electro-thermal heating from an electrical discharge in a small cavity, which forces the gas in the cavity to exit through a small hole as a high-speed jet. With this method of actuation, pulsed plasma jets can achieve pulsing frequencies on the order of kilohertz, which is on the order of the instability frequency of many lab-scale shock wave-boundary layer interactions (SWBLI). The interaction under investigation was generated by a 20° compression ramp in a Mach 3 flow. The undisturbed boundary layer is transitional with Re[subscript theta] of 5400. Surface oil streak visualization is used in a parametric study to determine the optimum pulsing frequency of the jet, the optimum distance of the jet from the compression corner, and the optimum injection angle of the jets. Three spanwise-oriented arrays of three plasma jets are tested, each with a different pitch and skew angle on the jet exit port. The three injection angles tested were 22° pitch and 45° skew, 20° pitch and 0° skew, and 45° pitch and 0° skew. Jet pulsing frequency is varied between 2 kHz and 4 kHz, corresponding to a Strouhal number based on separation length of 0.012 and 0.023. Particle image velocimetry is used to characterize the effect that the actuators have on the reattached boundary layer profile on the ramp surface. Results show that plasma jets pitched at 20° from the wall, and pulsed at a Strouhal number of 0.018, can reduce the size of an approximate measure of the separation region by up to 40% and increase the integrated momentum in the downstream reattached boundary layer, albeit with a concomitant increase in the shape factor. / text

This work focuses on the integration of microfluidics and dielectrophoresis(DEP) with the principles of field flow fractionation (FFF) to create a continuous-flow isolator for rare and viable circulating tumor cells (CTCs) from peripheral blood mononuclear cells (PBMNs) drawn from cancer patients. The method exploits differences in the plasma membrane capacitances of tumor and blood cells, which correspond to differences in the membrane surface areas of these cell types. DEP-FFF was first adapted to measure cell membrane capacitance, cell density and deformability profiles of cell populations. These properties of the NCI-60 panel of cancer cell types, which represents the wide functional diversity of cancers from 9 organs and leukemia, were compared with the normal cell subpopulations of peripheral blood. In every case, the NCI-60 cells exhibited membrane capacitance characteristics that were distinct from blood and, as a result, they could be isolated from blood by DEP. The heightened cancer cell membrane capacitances correlated strongly with membrane-rich morphological characteristics at their growth sites, including cell flattening, dendritic projections, and surface wrinkling. Following harvest from culture and maintenance in suspension, cancer cells were found to shed cytoplasm and membrane area over time and the suspended cell populations developed considerable morphological diversity. The shedding changed the cancer cell DEP properties but they could still be isolated from blood cells. A similar shedding process in the peripheral blood could account for the surprisingly wide morphological diversity seen among circulating cells isolated from clinical specimens. A continuous flow DEP-FFF method was devised to exploit these findings by allowing CTCs to be isolated from the nucleated cells of 10 mL clinical blood specimens in 40 minutes, an extremely high throughput rate for a microfluidic-based method. Cultured cancer cells could be isolated at 70-80% efficiency using this approach and the isolation of CTCs from clinical specimens was demonstrated. The results showed that the continuous DEP-FFF method delivers unmodified, viable CTCs for analysis, is perhaps universally applicable to isolation of CTCs from different cancer types and is independent of surface antigens - making it suitable for cells lacking the epithelial markers used in currently accepted CTC isolation methods. / text

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<p>When the producers’ responsibility for packaging was introduced in Sweden in 1994 the industry set up public recycling stations to facilitate the collection of the waste material. In order to establish recycling stations at suitable locations the municipalities assist the industry’s service organization for operation of the recycling stations, the Package and Newspaper Collection Service (Förpacknings- och tidningsinsamlingen, FTI). The objectives of this thesis are to improve the service of the public recycling stations within Lidingö town and to increase the accessibility to these stations for the inhabitants of Lidingö. The Municipal authority of Lidingö in consultations with the FTI will use the collected information on the attitudes of the inhabitants in order to bring the recycling system into line with the opinions of the inhabitants.</p><p>The information on the attitudes of the inhabitants towards the public recycling stations has been collected through an opinion poll. About half of those asked are living in blocks of flats while half are living in self-contained houses. In order to secure the differences in attitudes between different forms of living, sex, and age, hypotheses tests were conducted on selected parts of the collected material. New locations for public recycling stations have been suggested and assessed on the basis of accessibility, the risk of littering, the level of noise, the traffic situation, existing hard surfaces and property ownership.</p><p>The inhabitants of Lidingö want the public recycling stations to be located near their homes, near main roads or near shops in order to be accessible. Car is the main means of transport to the recycling stations. Women and people living in blocks of flats walk to the recycling station to a greater extent than men and those living in self-contained houses. The recycling stations ought to be asphalted and well-lit in order to decrease the risk of littering.</p><p>Many inhabitants of Lidingö, living in areas where the population density is high, lack access to public recycling stations within walking distance. New recycling stations should preferably be located in these housing areas. Ten new suggested locations will, if they are adopted, increase the number of inhabitants living within walking distance of a recycling station.</p> / <p>Då producentansvaret för förpackningar infördes 1994 valde näringslivet att lösa insamlingen av förpackningar genom att sätta upp återvinningsstationer till vilka hushållen kan lämna det utsorterade materialet. För att göra det möjligt att placera ut återvinningsstationer på lämpliga platser bistår kommunerna näringslivets serviceorganisation, Förpacknings- och tidningsinsamlingen, med lokaliseringsförslag. För att anpassa insamlingssystemet till lokala förhållanden är Förpacknings- och tidningsinsamlingen ålagd att samråda med kommunerna.</p><p>Examensarbetet syftar till att förbättra servicen på återvinningsstationerna på Lidingö och öka tillgängligheten för kommuninvånarna. Informationen om lidingöbornas attityder ska användas vid samråd mellan kommunen och Förpacknings- och tidningsinsamlingen för att anpassa insamlingssystemet efter kommuninvånarnas önskemål.</p><p>Genom en postal enkätundersökning har lidingöbornas attityder till återvinningsstationerna´utretts. Hälften av de tillfrågade bodde i flerfamiljshus medan den andra hälften bodde i småhus. För att säkerställa skillnader i attityder mellan olika boendeformer, kön och åldrar utfördes hypotesprövningar på utvalda delar av materialet. Platser för nya återvinningsstationer har tagits fram och bedömts utifrån tillgänglighet, risk för nedskräpning, bullerstörning, trafiksituation, markägarförhållanden samt befintliga hårdytor och tillfartsvägar.</p><p>Lidingöborna vill att återvinningsstationer ska placeras i närheten av hemmet, större bilvägar eller i anslutning till affärer för att vara lättillgängliga. Det huvudsakliga transportmedlet till återvinningsstationen är bil. Kvinnor och boende i flerbostadshus tar sig i större utsträckning till fots till återvinningsstationen samt anser i högre grad att återvinningsstationerna ska ligga i närheten av hemmet än vad män och boende i småhus gör. Återvinningsstationerna bör vara asfalterade och välupplysta för att minska risken för nedskräpning.</p><p>Stora områden på Lidingö med hög befolkningstäthet saknar helt tillgång till återvinningsstationer inom gångavstånd. I dessa bostadsområden bör nya återvinningsstationer prioriteras. Tio lämpliga platser för nya återvinningsstationer har lokaliserats vilka, om de upprättas, ökar andelen lidingöbor som har möjlighet att ta sig till fots till återvinningsstationen.</p>

Cereals contain naturally occurring biopolymers (for example proteins and starches) that can be used as renewable raw materials in a variety of speciality chemical applications. The separation of protein and starch biopolymers from wheat is well established and relies on a group of proteins called glutens that have a unique network-forming functionality. Oat and other cereals do not naturally contain these gluten proteins and typically rely on chemical-based separation techniques which alter the chemical and physical structures and damage the inherent natural functionality of the biopolymers. This research study investigated the separation of the protein and starch fractions from cereals using the Al-Hakkak Process, a new aqueous process. This process involves adding water and wheat gluten protein to cereals that do not contain gluten. The wheat gluten interacts with the cereal proteins, facilitating the separation of the starch and protein fractions whilst retaining their inherent natural functionality. The aim of this research project was to investigate and optimise the pilot scale separation performance of the Al-Hakkak Process using oat flour. As very little prior research had been carried out, the focus was to characterise the oat starch and protein separation performance and gain an understanding of the mechanisms involved. A variety of techniques were employed. Large scale deformation rheology was used to gain an understanding of the oat-gluten dough rheology and establish the relationship between the rheology and the separation performance. Confocal scanning laser microscopy was used to investigate the structure of the oat-gluten protein network. The molecular interactions between the oat and gluten proteins were studied using gel electrophoresis. The network-forming functionality of the new oat-gluten protein was explored. The influence of various processing parameters on the pilot scale separation performance was investigated and the results compared with other data collected through the study to identify key processing parameters. This research programme has resulted in interesting, encouraging and some unexpected outcomes and these are discussed in detail in the thesis. It was concluded that an insoluble protein network formed in the oat-gluten dough and both kneading and extraction processes were found to contribute to the formation of this. A key conclusion was that the changes that took place in the oat-gluten dough were similar to, but not identical to, the changes that occur in wheat dough. It was proposed that the mechanism for the development of a protein network in oat-gluten dough differed from wheat dough for two main reasons: a) the presence of the oat flour disrupted the normal wheat gluten behaviour, and b) components in the oat flour altered the activity of the gluten proteins. The research identified key processing parameters for the Al-Hakkak Process including kneading time, gluten content, and sodium chloride content of the oat-gluten dough as well as sodium chloride concentration, pH, and temperature of the extract liquor. An important discovery was that the oat and gluten proteins interacted at a molecular level through reducible, covalent, bonding (most likely disulphide linkages) to form the insoluble protein network in the oat-gluten dough. It was concluded that these reducible bonds coupled the individual protein subunits to form new hybrid oat-gluten protein molecules (a combination of oat proteins and gluten proteins). Both insoluble and soluble proteins in the oat and gluten flour were involved in the formation of the insoluble protein network in the oat-gluten dough. This outcome has applications beyond the Al-Hakkak Process, as this new knowledge can be applied to the wider dough processing industry. It was concluded that the wheat gluten was the source of the protein network-forming functionality of the hybrid oat-gluten protein and that the oat proteins had a diluting effect. It was proposed that oat-gluten protein flour from the Al-Hakkak Process could be reused to replace the commercial wheat gluten flour in subsequent production batches. During spray drying of the starch stream, the soluble biopolymers in the extract liquor were found to act as an adhesive and glued individual starch granules together to form spherical agglomerates. Acidification of the extract liquor was found to enhance this agglomeration. It was proposed the acidified starch granules were sticker during spray drying due to the partial acid hydrolysis of the starch granule suface which enhanced the agglomeration.

A method of solubilizing and extracting proteins from by-products was tested. The raw materials used were finely homogenized and digested at 60(DEGREES)C and pH 10.5 for 30 to 120 minutes in the presence of 0.5% alkaline nonspecific bacterial proteases from Bacillus subtillis. The protein in solution was separated from nonsoluble and organic solvent soluble components by filtration or centrifugation. When desired, the proteinaceous solution was dried (preferably by spray drying). Raw materials that were test digested included keratin from turkey feathers, bovine skin collagen, shark waste, shrimp heads, whole squid, inedible chicken carcass, bovine blood plasma, slaughterhouse waste, cotton gin waste, Enteromorpha sp. (a marine alga), Batis sp. and Distycilus sp. (two halophytes), soybean meal, casein, and fibrinogen. With this method, plant proteins were 57.4% to 59.9% extractable and animal proteins were 75.8% to 93.0% extractable. The native protein hydrolyzed by the procedure was reduced to an average molecular weight of 10,000-15,000 daltons. Other changes characteristic of the digestion process were increased protein concentration and decreased ash concentration. Complementation of by-product proteins in Tetrahymena medium resulted in increased growth compared to Tetrahymena cultures using soy or casein as the sole protein source up to 1.25 times. Decreasing protein molecular weight resulted in decreased growth in Tetrahymena (up to 4 times). Shrimp fed hydrolyzed animal proteins grew only 37.6% to 54.8% as much as squid-fed shrimp controls. White leghorn chicks fed 40% protein as hydrolyzed by-product proteins grew as much as chicks fed a commercial-type milo-soy diet supplemented with methionine. Amino acids from smaller peptides were more rapidly absorbed and more completely incorporated into muscle mass by chicks than were larger peptides.

A mathematical model has been developed which describes the fluid exchange from a capillary network of realistic topology, and calculates the spatial distribution of extravascular pressure. In this model, the capillaries are represented by a superposition of sources and sinks, resulting from a D'Arcy's Law description of flow in tissue of uniform fluid conductivity. The combination of this representation and Starling's Hypothesis, which relates the forces influencing transmural fluid exchange, yields an integral equation of the second kind which is solved numerically for the source strength distribution. Two important features of this approach are that: (i) it allows for interaction between the local tissue pressure field and fluid exchange (the model is called, therefore, the tissue pressure interaction model); and (ii) complex network morphologies are easily modeled. In single capillaries, this interaction, which decreases the predicted fluid exchange, increases with the magnitude of the ratio of capillary wall to extravascular fluid conductivities. For multiple capillaries, in addition to the "self" interaction of a capillary with the local extravascular pressure field, there is the possibility of interaction between capillaries ("capillary-capillary" interaction). The ratio of conductivities, and the additional factors of intercapillary distance and the number of capillaries, also affect interaction in capillary networks. Although interaction is only a weak function of intercapillary distance, it depends strongly on the number of capillaries. The major result from this work is that for the entire physiological range of conductivity ratios, interaction cannot be neglected in predicting fluid exchange. Although tissue pressure interaction affects the magnitude of fluid exchange, it does not greatly alter the pattern of extravascular flow. Therefore, previous models which neglected interaction are not invalidated by the present findings. The effect of interaction on planar capillary networks within a semi-infinite tissue space was also investigated. Flow boundary conditions were imposed at opposed planar boundaries, parallel with the capillary network. Interaction was found to decrease with decreasing distance between the boundary and plane of the capillaries. It still exerted a large effect, however, for distances greater than one-fourth the reference capillary length.