This thesis characterizes parylene-C films with respect to biological micro-electro-mechanical system (BioMEMS) applications. BioMEMS devices have fueled the growth and research in the area of detecting, analyzing and identifying pathogens rapidly with precision in the bio-medical applications, thereby positively impacting millions of lives and made it extremely popular among researchers. These devices are fabricated using state-of-the-art techniques usually involving more than one material which typically has different biocompatibility and is not acceptable for various BioMEMS and biomedical applications; therefore, a special biocompatible coating is required. The parylene polymer is an example of such a coating as it is known for its biocompatibility (U.S. Pharmacopoeia (USP) Class VI) as well as possessing pinhole free surfaces with low penetrability which provide exceptional barriers to moistures and solvents. The vapor deposition process utilized for depositing parylene coating also provide conformable, uniform thickness throughout targeted sample even with high aspect ratio microstructures, and is compatible with both polymeric (e.g. PMMA, polycarbonate, etc.) and non-polymeric (e.g. nickel, silicon, etc.) substrates, as the samples are kept inside a room temperature (25° C) chamber where the final deposition step occurs. In this study, parylene coatings were characterized with respect to surface roughness, where roughness measurements show no significantly changes when parylene are deposited on smoother pristine PMMA (from ~Ra=2.66nm to ~Ra=2.85nm) and polycarbonate (from ~Ra=3.02nm to ~Ra=5.92nm) and reduces roughness of rougher surfaces (electroplated nickel from ~Ra=374nm to ~Ra=201nm). Parylene is also characterize with respect to surface energy by measuring contact angles, where pristine parylene surface (contact angle = ~89°) becomes more hydrophilic by treating it with oxygen plasma (contact angle = ~32°). Surface modification was used to control the number of live cells (HeLa) attaching on parylene, where O2 plasma was used to increase this by 2-folds and altering substrate roughness helped in minimizing the cells adhesion to parylene.

Due to limited supply of traditional fossil based fuels, and increased interest in air and water quality along with other environmental concerns, there has been a rise in the utilization of biomass based energy sources. Many agricultural materials can be used for the production of biofuels, including materials that are typically underutilized such as sweet sorghum bagasse and otherwise nuisance species such as Chinese tallow tree seeds. The goal of this project was to examine the relationship between the dielectric properties of sweet sorghum bagasse and Chinese tallow tree (CTT) seeds, respectively, and frequency and moisture content; to determine pertinent thermal properties of these materials, and to optimize process parameters of a continuous belt microwave drying system for improved biofuel production. Prior to microwave drying, the elemental composition, fatty acid composition, oil content, and various thermal properties for each of the component layers of CTT seeds were investigated. These tests revealed dramatic differences between each of the component layers of CTT seeds. For both sorghum bagasse and CTT, the dielectric properties across a range of moisture contents and frequencies were measured. The values obtained here were applied to the calculation of the penetration depth of microwaves through the materials in order to illustrate how these materials would behave when exposed to microwave energy. The dielectric properties for each material were found to be dependent on both frequency and moisture content. For microwave drying tests, the parameters investigated include microwave power levels (300W, 750W, and 1.2kW) and ambient air temperatures (room temperature and 55°C) with total residence time of 5 minutes. Data collected included humidity, temperature, sample surface temperature, moisture content, and absorbed microwave power. The moisture removed when microwaves are used is greatly in excess of the internal air moisture holding capacity, due to forced removal of water from the samples via pressure gradients generated by direct interaction with the water molecules in the matrix. Results indicate that microwave drying achieves results better than the control with respect to moisture removed per unit energy input.

No description available.

Thesis (M.S.)--Oklahoma State University, 2009. / Vita. Includes bibliographical references.

Thesis (M.S.)--Ohio State University, 1967. / Includes bibliographical references (leaves 109-112). Available online via OhioLINK's ETD Center

Thesis (M.S.)--Texas A & M University, 2003. / "Major Subject: Biological and Agricultural Engineering." Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--Texas A & M University, 2003. / "Major Subject: Biological and Agricultural Engineering." Title from author supplied metadata. Includes bibliographical references.

In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using two microwave systems were investigated in this study. In the first part, utilizing a batch system, parameters tested were catalyst concentration (1-4 wt.%), solvent ratio (2-6 v/w), reaction time (15-60 min) and temperature (50-70°C). A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Dohlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this process were determined as: catalyst concentration of 1.74 wt.%, solvent ratio about 3 (v/w), reaction time of 20 min and temperature of 58.1°C. GC and H-NMR were used to profile the fatty acid methyl esters and reaction conversion, respectively. All methyl esters produced using this method met ASTM biodiesel quality specifications. For the second part, a continuous In-situ transesterification of the seeds using a microwave-assisted CSTR system was investigated with determination of kinetic parameters. A high production yield of 90.02% with 97.53% conversion rate was obtained in 24 min CSTR residence time at a methanol/hexane/CTT seed ratio of 3:3:1 (v/v/w), a microwave heating power of 290 W and 14 sec exposure time, reaction temperature of 60°C and sodium hydroxide catalyst loading of 4% wt. of oil. The experimental data fits the first order reaction kinetics. The values of rate constants at different temperatures and the corresponding activation energy were found out to be 0.083-0.087 min -1 and 1987.82 J/mol, respectively. The thermodynamic parameters values such as Gibbs free energy (ÄG), enthalpy (ÄH) and entropy of activation (ÄS) were also determined. The positive values of ÄG and small negative value of ÄH indicated that the reaction has an unspontaneous/endergonic nature and is slightly exothermic.

<p> Slow sand filters (SSF) have been used to treat surface water to drinking water standards for over a century. Today many cities, including London still treat surface waters to drinking water standards, however because there are viruses that are not efficiently removed by a slow sand filter and are not killed by chlorine, communities have turned to the use of micro filtration and/or reverse osmosis to provide safe drinking water. These technologies are much more efficient if organics are removed and turbidity reduced to less than 1 Nephelometric Turbidity Units (NTU). The greenhouse industry is another potential user of slow sand filters. They are not able to recycle irrigation drainage water without it being treated to reduce bacteria, virus, and fungi. </p><p> The objective of this research was to develop management strategies for SSF that specifically meet the needs of entities using SSF for pretreatment of potable water or use in a greenhouse. This data was used to test a scour system that resulted in scouring 80 percent of the organic layer in the filter and suspending the solids for 40 minutes. A conceptual design was done for a full scale SSF that took advantage of the scour and suspension data to clean the SSF at the end of a run cycle. SSF were able to consistently produce water with a turbidity less than 1 (NTU) and with the infiltration capacity of 0.27 m³m^-2. For greenhouse effluent a 1,000 square meter greenhouse that is discharging 3,600 L d^-1 of drainage water would require a 12.6 m² SSF, and the SSF for the community requiring treatment of 4.7 million liters per day of raw water was 730 m². The innovative cleaning system based on an air/water jet was developed to clean the SSF. Experiments were run to determine the amount of time that the solids were suspended and a scour system developed to exceed these times. The entire time for cleaning and recovery of the SSF was an average of 118 minutes for the greenhouse system and 170 minutes for the SSF serving a small community.</p>

Filtrate, which accounts for almost 15 to 20% of the mixed juice produced in a raw sugar factory, is usually recirculated, which is detrimental to the process. This can lead to: increased sugar inversion and reduction in both sugar quality and clarifier performance. Previous attempts on filtrate clarification have shown limitations for its implementation due to the long residence times of the clarifiers, complex operations and low quality of clarified filtrate. A filtrate clarification pilot plant using a very short residence time clarifier (10 minutes) was designed and tested during the 2012 Louisiana sugarcane harvesting season. Louisiana Low Turbulence technology (LLT) that has been successfully used for mixed juice clarification was utilized. The results show that when clarified filtrate and the clear juice of the main factory clarifiers were mixed in a proportion of 1:5, no significant difference was found between the clarified juice and this mixture. Additionally, the suspended solids removal achieved in the filtrate clarifier was as high as 95% and the color of the clarified filtrate was lower than the clear juice color. Finally, these results suggest that the unit operated satisfactorily and a full scale implementation of this technology can avoid the undesirable recirculation of filtrate by using a simple process, with high throughput and small footprint.