Coagulopathy, a condition in which blood coagulation is impaired, can be inherited or result from a variety of conditions including severe trauma, illness or surgery. Perioperative monitoring of a patient’s coagulation status is important to identify coagulopathic patients. Thromboelastography or TEG remains the gold standard for whole blood coagulation monitoring. However, TEG suffers from certain well-documented drawbacks such as contact containment and manipulation of the blood sample, large and uncontrolled strain, and the inability to distinguish the contribution of elasticity and viscosity during blood coagulation. We developed a non-contact blood rheometer which uses a single drop of blood to measure its viscoelastic properties. Small sample size (typically 5-15 μL), low shear strain (linear viscoelasticity), and non-contact manipulation and containment of samples make this technique unique for real-time monitoring of blood coagulation. In the first part of this work, we addressed the development of the technique, benchmarking the results against known material properties standards. We observed large amplitude oscillations of the levitated drop results in multiple resonance modes and excessive dissipation. We suggested upper bound limits for drop oscillation amplitudes required to satisfy the Lamb theoretical expressions for drop frequency and damping. In the second part, we applied our technique to study sickle-cell disease. Our technique showed that the shape oscillation of blood drops was able to assess an abnormally increased viscosity in sickle cell patients when compared with normal controls over a range of hematocrit. Furthermore, the technique was sensitive enough to detect viscosity changes induced by hydroxyurea treatment. The third part of this work focused on blood coagulation monitoring. The technique showed sensitivity to coagulation parameters, such as platelet count, calcium ion concentration, and hematocrit. A comparison of the results with TEG showed coagulation started sooner in the levitation technique, but with a lower rate and lower maximum stiffness. Thus, the technique developed can be used as a monitoring tool to assess blood mechanical properties sensitively enough to be of use in clinical diagnostic settings. / 2020-06-04T00:00:00Z

This dissertation talks about the dynamics of the drop impact in two parts, the impact of the drop on the deep liquid pool with singular jet and sound emission, and the bouncing drop with filaments on the superhydrophoic solid surface. First, we use experiments and simulations to study drop impacts on a deep liquid pool, with a focus on fine vertical jetting and underwater sound emission from entrapped bubbles, during the rebounding of the hemispherical crater. The much larger parametric complexity introduced by the use of two immiscible liquids, compared to that for the same liquid, leads to an extended variety of compound-dimple shapes. The fastest jet occurs from the rebounding of a telescope dimple shape without bubble pinch-off, at around 45 m/s, which leaves a toroidal micro-bubbles from the air-cusp at the base of the dimple. The finest jets have diameter of only 12 µm. A new focusing mechanism for singular jetting from collapsing drop-impact craters is then proposed based on high-resolution numerical simulations. The fastest jet is confined in a converging conical channel with the entrained air sheet providing a free-slip outer boundary condition. Sound can be emitted from the oscillation of the entrapped dimple-bubble, while the tiny bubble from the initial impact is induced to oscillate with the entrapped bubble, triggering the double crest of the acoustic signal. We track the compression of the bubble volume from the high-speed imaging and relate it to the hydrophone signal. In the second part, we investigate the impact of a polymeric drop on a superhydrophobic solid substrate with micropillar structure. The drop spreads on the substrate, wets the tops of the pillars, and rebounds out of the superhydrophobic soild surface. Numerous liquid filaments are stretched from the liquid drop to the attached adjacent pillars, and minuscule threads would be left on the top of the pillars using the inclined superhydrophobic solid surface. The well-organized exposed polymer threads are left on the top of the pillars after solvent evaporation. The thickness of the deposition of filament bundles using the bouncing method are thinner than those formed by drop evaporation or drop rolling from SEM (scanning electron microscope) observation.

This work encompasses studies on the development of biocontrol strategies to manage the disease lettuce drop, caused by the fungi Sclerotinia sclerotiorum and S. minor, using the mycoparasitic fungus Coniothyrium minitans, and to better understand interactions during mycoparasitism at the biochemical level. Results from field experiments revealed that two applications of C. minitans at manufacturer recommended rates significantly reduced the incidence of lettuce drop caused by S. sclerotiorum but not by S. minor. Applications of other biocontrol products tested did not significantly reduce disease incidence caused by either pathogen. Sclerotium population studies revealed that soil populations of S. sclerotiorum in lettuce production fields ranged from 0.08 to 2.9 sclerotia/100g of soil and were generally aggregated in their distribution. Continued field studies revealed that there was no significant effect of irrigation (sprinkler vs furrow) on either the impact of sclerotium density or the efficacy of C. minitans. Studies on the evaluation of different application rates of Contans against S. minor revealed that two applications of Contans at 5 X manufactures recommended rates significantly reduced the disease incidence. Examination of sclerotial exudates of Sclerotinia spp. revealed that crude exudates from both Sclerotinia spp. stimulated C. minitans spore germination and the stimulation was due to compounds within the polar fraction. Studies on the role of lectin-carbohydrate binding during fungal-mycoparasite interactions revealed that many plant lectins as well as crude proteins extracted from sclerotia of either Sclerotinia spp. induced agglutination of C. minitans spores in vitro. Spore germination of C. minitans stimulated by sclerotial exudates of either Sclerotinia spp. was significantly inhibited in the presence of the lectin Con A but not other plant lectins. In vitro studies on the directional growth of C. minitans preceding mycoparasitism revealed the involvement of G proteins for optimal response of C. minitans toward Sclerotinia stimulus.

No description available.

No description available.

In this experimental investigation the evaporative behaviour of liquid droplets of both pure fluids and fluids containing nanoparticles was studied. Initial tests were conducted on drops of pure volatile liquids using IR thermography, and the effect of substrate material, drop composition, and substrate temperature was investigated. The effect of the addition of nanoparticles to the liquid drops was then investigated using a contact angle analyser which could record the drop profile in time. The effects of liquid composition, nano-particle composition, nanoparticles concentration, substrate hydrophobicity, and substrate temperature were all studied. Results obtained from IR thermography showed that there exists interfacial temperature instabilities in evaporating volatile drops, the appearance of these fluctuations was found to be dependent on the liquid and substrate in question and are self generated temperature gradients resulting from non-uniform evaporation. A stability analysis was conducted and the results give a good agreement with experimental results. The addition of nanoparticles to a liquid drop was found to alter the evaporative behaviour by enhancing pinning of the drop contact line and preventing the drop radius from shrinking. By manipulating the concentration of the particles suspended in a drop, a stick-slip evaporative process was achieved, leading to rings of particulate material formed upon total evaporation. By varying parameters such as substrate hydrophobicity, nanoparticle concentration, liquid composition, and substrate temperature, many distinct nanoparticle deposit patterns were observed upon total evaporation. It was shown that by varying these parameters, many different patterns could be achieved, and that inside these deposit patterns regular formations such as particulate rings, radial lines, and cellular structures were present.

The purpose of this research is to examine the longevity of the stereotype of the tragic mulatto in American film history. Specifically, my research focuses on the portrayals and perceptions of biracial actresses. Media informs, entertains, and influences how we, and especially youth, self-identify and interact with others. This research focuses on the portrayal of biracial actresses throughout film history. It is also important in its investigation of the perpetuation of the one-drop rule. In this research, I will examine if historical stereotypes of tragic mulatto are apparent in contemporary Hollywood film. The methodologies used in this research include a content analysis of films with biracial actresses and an online survey of respondents’ perceptions of four actresses. Statistical techniques used for analysis include ordinary least square regression and multinomial logistic regression. Findings suggest that the tragic mulatto stereotype is not blatant in contemporary Hollywood film, but issues of colorism may be apparent.

Since the 1980s, pre-registration nurse education has undergone dramatic changes that have led to the creation of a new course - Project 2000 - and its delivery within the Higher Education sector. Very little written during this period has addressed the issue of nurse learner wastage/persistence. The literature on nurse learner wastage/persistence prior to this period has tended to be largely atheoretical in nature. One of the chief objectives of this study was to produce a much more complex picture of wastage/persistence. This involved the building of a theoretical framework designed to explore one aspect of voluntary wastage - the interaction between integration and wastage/persistence, and which could capture the complexity of the phenomenon by taking into account the interaction between the individual and the institution within the process of wastage/persistence. This study draws on Tinto's (1975) Student Integration Model, which identified the learners' integration into an institution to be one of the critical factors in understanding the wastage/persistence of learners, as well as on some of the studies within the area of nurse learner wastage/persistence which have examined the role of a learner's identity in the wastage/persistence process. Accordingly, this study defined integration in terms of how well a learner has adopted the identity/ies afforded to them by the institution. Finally, drawing inspiration from Foucault (1988, 1990,1991), this study re-conceptualised identity in terms of the concept of subjectivity and defined integration in terms of how well the learner was able to subscribe to the discourses (and the subject positions that these made available) that constituted the given institution. A multiple case study was carried out that focused on leavers and stayers in the first year of a Project 2000 course in three particular cohorts within a particular institution. A modified version of discourse analysis, referred to as MODA (Meaning Orientated Discourse Analysis), was used. Two major discourses were identified which offered the learner a number of contradictory subject positions regarding what it means to be a learner and a nurse - the 'autonomous' and the 'apprentice' discourse. It was found that stayers were those most able to manage these contradictory subject positions offered by these discourses. This meant that they were more playful in their discursive reading patterns than leavers. This playfulness implied they were not only doing a lot more with these discourses, but that that the nature of what they were doing enabled them to accept and embrace the contradictory notions of what it means to be a learner and a nurse existing in the institution. The stayers' management of discourses was a reflection of the high level of integration that they had achieved within a institution that is riddled with two incommensurable discourses which offer competing definitions of what it means to be a nurse and a learner.

This study was conducted to determine the effects of compression on pressure drops in non-metallic flexible duct. Duct sizes of 12”, 14” and 16” diameters were tested at a five different compression ratios (maximum stretch, 4%, 15%, 30% and 45%) following the draw through methodology in ASHRAE Standard 120 -1999 – Methods of Testing to Determine Flow Resistance of Air Ducts and Fittings. With the pressure drop data gathered, equations were developed to approximate the pressure loss at a given air flow rate for a given duct size. The data gathered showed general agreement with previous studies showing an increase in compression ratio leads to an increase in static pressure loss through the duct. It was determined that pressure losses for compression ratios greater than 4% were over four times greater than maximum stretched flexible duct of corresponding duct size. The increased static pressure losses can lead to decreased performance in HVAC systems. The findings of this study add to the existing ASHRAE and industry data for flexible duct with varying compression ratios.

No description available.