Emulsions are commonly found both in nature and industry. Due to the complex nature of emulsion systems, their interfacial properties and stability are poorly understood, particularly the influence of droplet deformability on the colloid and interfacial behaviour. This study has highlighted the role of emulsion droplet cross-linking (deformability and penetrability) on droplet surface chemistry, droplet colloidal stability and adsorption at the droplet-water interface and provides insight into methods for enhancing the performance of emulsion formulations.

The aim of this study was to explore the properties of thermal field in spray cooling via experiments. The nozzle diameter (dj) used herein was 200 £gm and the heating surface measured 45 mm ¡Ñ 45 mm. The study was divided into two parts for experiments and analyses. In the first part, with DI water and FC-72 (dielectric liquid) as the working media, the changes in the liquid film thickness on the heater surface under different values of heating power were observed; heat input (Q) and value of gauge pressure (£GP) were taken as the main parameters for discussing the influence of these two parameters on the liquid film thickness in spray cooling. The second part, with DI water as the working medium, adopted the £gLIF system (fluorescent dye: Rhodamine B; concentration: 1.5¡Ñ10-4 M) to measure the effect of different working medium temperatures (23 ¢XC, 30 ¢XC, and 40 ¢XC) on the global temperature distribution, liquid film temperature changes on the heater surface and the thermal field condition of spray cooling, with an aim of exploring the internal physical phenomena of the droplets during cooling.

Accompanied with the improvements of instrument, design, mass spectrometer can provide rapid detection speed, accurate molecular weight of the analyte, and analyte structure, which was identified by tandem mass spectrometry (MS / MS). Because of rapid detection speed of mass spectrometer not only can be applied for real-time detection of the signals of the reactants and products in chemical reactions, but also was validated to detect the intermediates, which have existed in a very short time. For real-time monitoring of liquid phase chemical reactions, it not only must has an the rapid detection speed of mass spectrometer, but also have a suitable ionization source, which can assist that neutral analytes in the liquid directly fused into gas phase and be ionized to form analyte ion. In this study, ion spray ionization source was applied to explore the drolpet-synthesis reaction in the gas phase. In the experimental process, pneumatic nebulizer was validated for producing neutral droplets. The atomization effect is mainly caused by validating high-speed air flow through the liquid surface to shatter the liquid solution into population of droplets. In this experiment, two pneumatic atomizer set at a particular angle for spraying neutral droplets; some of neutral droplets with different analytes would fused into larger one in the gas phase. At the same time, reactant A and reactant B in the fused droplet would process chemical reaction in just a few hundred microseconds. End of the chemical reaction, fused droplets was sent near the entrance of MS inlet by the transmission of gas flow, dry air eluted from mass entrance outflow (dry gas) was validated for the desolvation. Based on the field ionization mechanism, induced electrospray ionization was occurred when MS inlet applied with 4.5 kV. Then, analyte ions via induced electrospray ionization were transferred to the inner of MS inlet and detected by mass spectrometer. In this experiment, several experimental parameters have been discussed and optimized including the angle of nebulizer (15 degrees - 90 degrees), the flow rate of nebulizing gas (3 psi -15 psi), the flow rate of sample solution (100 £gL/hr. - 500 £gL/hr), the flow rate of dry gas (3 L/min - 12 L/min) and the temperature of dry gas (50 oC-300 oC) for improvement of the reaction process and ionization efficiency. Finally, the droplet-synthesis reaction was performed under the optimal experimental parameters. The derivatives of aniline as reagent A, consisting a phenyl group attached to the different functional groups including hydroxyl group (-OH), nitric group (NO2), varied the different functional groups to change the reaction rate of reactant A in the chemical reaction. Then, benzaldehyde and acetic anhydride as reagent B was separately reacted with reagent A via droplet synthesis process to perform addition-elimination reaction. Beside, all of the tested chemical reactions through droplet-synthesis device were also re-verified by the liquid phase chemical reaction. Through the observation of mass spectra, The comparison of the differences (i.e. intermediate and product) between droplets synthesis reaction and liquid phase chemical reaction can also be obtained.

No description available.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: crown; splash; spreading; oscillatory; droplets; microgravity; viscosity; map; stability; solid surface; surface tension; gravity. Includes bibliographical references (p. 111-113).

Hepatitis C virus (HCV) is remarkably capable of efficiently hijacking host cell pathways including lipid metabolism in the liver in order to create pro-viral environments for pathogenesis. It is becoming increasingly clear that identifying small molecule inhibitors that target host factors exploited by the virus will expand available HCV treatment options. As such, a thorough understanding of host-virus interactions is critical to the development of alternative therapeutic strategies. Hepatic lipid droplets (LDs) are recruited by HCV to play essential roles in the viral lifecycle. The intracellular location of LDs is modified upon interacting with viral structural core protein. This enables formation of platforms that support viral particle assembly. Because these interactions are non-static, capturing its dynamic processes in order to better understand viral assembly can be achieved with label-free molecular imaging enhanced with live-cell capabilities. Chemical biology approaches that includes CARS microscopy employed in a multi-modal imaging system was used to probe interactions between HCV and host LDs. By successfully tracking LD trajectories, we identified core protein’s ability to alter LD speed and control for LD directionality. Using protein expression model systems that allowed for simultaneous tracking of core protein and LDs, our data revealed that mutations in the core protein region that vary in hydrophobicity and LD binding strengths, are factors that control for differential modulation of LD kinetics. Furthermore, we measured bidirectional LD travels runs and velocities, and observed critical properties by which core protein induces LD migration towards regions of viral particle assembly. Given that many steps in the HCV lifecycle are directly linked to host lipid metabolism, it is not surprising that disrupting lipid biosynthetic pathways would negatively affect viral replication. From this outlook, we explored small molecule inhibitors that targeted several lipid metabolic pathways to study its antiviral properties. Using fluorescent probes covalently labeled to viral RNA, we captured the visualization of disrupted replication complexes upon antagonizing nuclear hormone receptors that are linked to regulating lipid homeostasis. Correspondingly, biochemistry and molecular imaging techniques were also employed to identify novel antiviral mechanisms of small molecule inhibitors that target additional HCV-dependent lipid metabolic pathways.

No description available.

Parametric resonance is a particular type of resonance in which a parameter in a system changes with time. A particularly interesting case is when the parameter changes in a periodic way, which can lead to very intricate behavior. This di↵ers from periodic forcing in that solutions are not necessarily periodic. A system in which parametric resonance is realized is when a fluid bath is shaken periodically, which leads to an e↵ective time dependent gravitational force. This system will be used to study the onset of surface waves in a bath with non-uniform topography. A linear model for the surface waves is derived from the Euler equations in the limit of shallow waves, which includes the geometry of the bottom and surface tension. Experiments are performed to compare with the proposed model and good qualitative agreement is found. Another experiment which relies on a shaking fluid bath is that of bouncing fluid droplets. In the case of two droplets the shaking allows for a larger bouncing droplet to attract a smaller moving droplet in a way that creates a bound system. This bound system is studied and shows some analogous properties to quantum systems, so a quantum mechanical model for a two dimensional atom is studied, as well as a proposed model for the droplet-wave system in terms of equations of fluid mechanics.

No description available.

No description available.