Thesis (M. S.)--Texas A&M University, 2005. / "Major Subject: Biological and Agricultural Engineering" Title from author supplied metadata (automated record created on Feb. 23, 2007.) Vita. Abstract. Includes bibliographical references.

The kinetics of fecal coliforms (FC) decay and regrowth were analyzed under laboratory conditions using filtered dairy wastewater under anaerobic conditions. The mean specific growth rates during the regrowth phase, µr , in the batch study were 1.79, 1.46, and 1.27d-1 for initial organic carbon concentrations of 478, 235 and 127 mg/L COD, respectively. The substrate concentrations had a significant impact on the FC regrowth. A maximum specific growth rate (mmax) of 1.92 d-1, and half-saturated coefficient (ks) of 60.92mg/L were determined from these data. The mean dark FC decay rate coefficients, kd , at 35oC in the batch study were 2.19, 2.52 and 3.29 d-1 for organic carbon concentrations of 478, 235 and 127 mg/L COD, respectively. The effect of substrate concentrations on the FC dark decay rate coefficient was significant (P-value=0.0004). A simple linear regression equation of kd= 3.460-0.00497 *S was obtained for the batch study. The decay rate coefficients of FC, determined from non-steady state data, for hydraulic retention times of 1.7, 3.5, and 6.9days at 25oC were 1.34, 1.57, and1.38 d-1, respectively. The mean µr values in the CSTR at 35oC were 0.83, 2.85, 2.68, 2.29, 2.11 d-1 for the hydraulic retention times of 1.7, 3.5 (Trial 1), 3.5 (Trial 2), 3.5 (Trial 3) and 6.9days, respectively. mmax of 4.00d-1, and ks of 275.12mg/L were obtained for the CSTR studies. mmax of 3.03 d-1, and ks of 169.01mg/L was obtained for the combined data from batch and CSTR studies. The mean kd-ìd values determined from the non-steady state data for hydraulic retention times of 1.7, 3.5 (Trial 1), 3.5(Trial 2), 3.5 (Trial 3), and 6.9days at 35oC were 4.67, 1.72, 0.72, 1.63, and 5.87d-1, respectively. These results indicate that the 3.5days hydraulic retention time reactors were near steady state conditions.

Design and calibration of spreading equipment for agricultural materials are critically important but is facing some limitations in time and costs. Lack of personnel and environmental constraints, as well as equipment features present challenges in the calibration process and results. The major objective of this project was to introduce and investigate the feasibility of integration of automated electrical equipment into this calibration process in order to optimize the overall procedure in terms of cost, time and precision as an ultimate goal. Specific objectives focused on optical techniques as well as novel accelerometer technology. A photo based method in detection of collected grains based on counting of particles was investigated. Results from tests with three different grain particles showed that the sensor could be used in applications up to 20gr of collected materials in one pass. The sensor could detect multiple particles passage at the same time, but was unable to go further than a certain sample weight of 20, 30 and 60 grams for ammonium sulfate, rice and urea respectively while maintaining acceptable precision. In this regard, physical characteristics of the mentioned granular particles were also investigated to better address the importance of physical uniformity in this sensing system. A novel set of sensing plates based on accelerometer technology were introduced and the practicality of the sensors was tested using the standard setup for measurement of spreading patterns. A comparison between the outputs of a set of identical accelerometer plates showed a close estimate of the trend which could be achieved in the same deposition using the traditional dry calibration process. Moreover, the introduced sensor was highly flexible and could be adjusted in various ways in order to better match the application demands. In this regard, the proposed sensor was also tested at 10 and 20 degree angles with respect to the horizon and the results indicated almost twofold improvement in resolution from 595mV/g to 955mV/g at 10 and 20 degrees respectively. This novel accelerometer based technique may be practical for improved automation of calibration techniques.

Operation S.A.F.E workshops, commonly known as fly-ins help agricultural pilots fine tune their aircraft for aerial application work. During the fly-in several ancillary measurements are recorded; aircraft speed, aircraft spray release height, air temperature and relative humidity, wind speed and direction. These measurements are recorded by personnel operating the flight line with manually operated sensors. Some of the difficulties arise when the lack of personnel and or experience level hinders the ancillary measurement, or when equipment becomes difficult to repair and/or replace. The objectives of this project are to design two automated sensor platforms to aid data collection and analysis for Operation S.A.F.E. type clinics. The first platform is the automated field measurement system (AFMS) and acquired aircraft ground speed and application release height measurements. The results from field experiments show that the AFMS was able to acquire representative aircraft ground speed data when the sensor was oriented at 45°. The AFMS was also able to acquire a series of 50 80 of height values after the aircraft passes over the height measurement sensor. A representative height value was able to be determined by averaging the 50 80 height values. The second platform is the new string analysis system (NSAS). This unit was developed to process liquid spray deposition patterns collected onto 1 mm diameter cotton string. The system was able to detect rhodamine water tracer RWT dye collected on the cotton string collector during the spray pattern analysis trials. The system produced a series of values which represented the florescence intensity of the RWT. The NSAS produced the optimum fluorometer sensor response when a distance of 2 mm between the sensor and string collector was implemented. The NSAS processes the string collector at speeds between 1.6 m/min to 5.0 m/min. The fluorescence sensor detected higher readings when operating at 1.6 m/min, however overall processing speed was greater than 28 minutes for standard string collector lengths of 45 m. The two automated systems have been field tested and the results indicate that prototypes have the potential to be further developed into tools for use with Operation S.A.F.E. calibration workshops.

Coastal land loss in Louisiana is occurring at astounding rates. New technologies for shoreline protection are needed that incorporate traditional engineering designs with natural systems (e.g., oyster reefs). Under optimal environmental conditions eastern Oysters (Crassotrea virginica) can biologically dominate artificial concrete reef structures used as coastal breakwaters within the intertidal zone. These reefs can also serve as oyster broodstock sanctuaries providing a nexus to the public oyster grounds benefiting the aquaculture industry. The use of biologically dominated, engineered breakwaters may provide a viable solution to coastal restoration and shoreline protection challenges. Biologically dominated coastal breakwaters can be integrated into coastal zone management strategies to preserve coastal resources by offering compatible uses across multiple disciplines. An experimental study was conducted at Rockefeller Wildlife Refuge monitoring material strength, sediment accretion, and oyster biometrics on high-relief, three-dimensional artificial reefs using concrete scaffoldings for growth substrates. Spat plate data on these reefs indicated the spring spatfall exceeded 10,000 spat/m^2 in some locations. Oyster shell height measurements of 50 cm were recorded after six months growth, with oyster counts exceeding 500 per m^2 on the artificial concrete modular breakwater reefs. Alternate concrete substrates (i.e., vitrified expanded clay) showed optimal strength and weight when compared to traditional higher density aggregates, weighing less than 50% by volume with no statistically significant difference in ASTM 39 standards for compressive strength (3,328 lbs with P<.001). Biologically dominated concrete structures showed a significant increase in ASTM 78 standards for flexural strength over time from an initial 28-day curing load of 100 lbs to loads of 479 lbs in six months and 1,344 lbs in two years. Pilot scale breakwater emplacements dominated by biological growth accumulated nearly 4 m3 of sediment over four years. Heavy and light density reef emplacements installed for less than one year accreted 1.6 and 0.37 m3 of sediment, respectively, relative to baseline cross-shore transects with no breakwater emplacements.

In many situations, the manure produced by confined animal feeding operations (CAFO) needs to be treated before being land applied in order to prevent negative impacts on the environment. Treatment methods are focused on reducing organics, recovering nitrogen and phosphorous. The purpose of this study is to evaluate the efficacy of burnt-lime (Ca(OH)2) and bentonite clay precipitation system of recovering phosphorous from dairy wastewater and alligator wastewater and trapping any possible emissions of ammonia (NH3). Wastewater samples of flush dairy manure from a collection pit, dairy wastewater from an anaerobic lagoon and alligator wastewater from an anaerobic lagoon were investigated in this study. The addition of burnt lime and bentonite clay solutions were found to be effective in removing 88.18% of total phosphorous (TP) and 100% of dissolved phosphorous (PO4-) from the flush dairy manure by the addition of 9% by volume of 10% lime solution (1:9 Ca(OH)2 to water) along with 0.9% by volume of 5% bentonite clay solution (24.25g in 485 mL water). The same concentrations of lime and clay solutions added in the same proportions to dairy lagoon wastewater resulted in a 99.86% reduction of TP and a 98.58% reduction of PO4-. The addition of 9.009% by volume of lime and 0.9% by volume of clay solutions to the alligator wastewater resulted in 99.95% and 95.76% removal of TP and PO4- respectively. The addition of lime and clay solutions resulted in raised pH of the wastewater. This led to a hypothesis of ammonium (NH4+) being converted to ammonia (NH3) and volatilized into the atmosphere. Acid traps were used in this study to evaluate the NH3 concentrations of wastewater, were found not to contain any detectable concentrations of ammonia indicating that there was minimal volatilization of NH3. The higher alkalinity values observed in all the wastewater samples indicated the presence of ammonium (NH4+) complexes in wastewater as ammonium hydroxide (NH4OH). Therefore, the addition of lime and clay solutions effectively removed most of the P present in the wastewater samples and there were no ammonia emissions detected.

Co-location of algae production facilities with sugarcane mills in Louisiana was investigated as a way to address the bottlenecks for algal biodiesel production. Using the process modeling software Sugars, an algal biodiesel production process was integrated with the operation of a typical-sized 10,000 metric tons/day (11,000 short tons/day) sugarcane mill to evaluate material and energy balances. A process is proposed wherein alga production is supplemented with energy, water, and CO2 available from a sugarcane mill. The Energy Return on Invested, EROI (a ratio of the energy produced/energy required) of the proposed algal biodiesel production process was 1.25; meaning 25% more energy can be produced than is required by the process. A sensitivity analysis showed that this number ranged from 0.8 to 1.4 when the range of values for oil content, CO2 utilization, oil conversion and harvest density reported in the literature were evaluated. A locally sourced alga, Louisiana strain, was evaluated for its suitability as a biodiesel feedstock and to justify some of the assumptions used in the model. Hexane and ethanol were compared as neutral and polar solvents for extracting oil from the alga in order to establish a range for oil yield; it was found that 5% and 37% by wt. of the alga could be extracted as crude oil by the two solvents, respectively. The crude oil was subjected to an acid catalyzed esterification to produce fatty acid methyl esters (FAME, i.e. biodiesel). Using gas chromatography mass spectrometry (GC-MS) it was determined that 17-19% of the crude oil was converted FAME for both solvents; therefore ethanol is a more effective solvent. By incorporating the lab-generated results into the assumptions of the computer model, biodiesel yield was projected to be 920,000 liters biodiesel/yr (240,000 gallons biodiesel/year) on 440 hectares (1,100 acres) with an EROI of 0.91.

Nano and micro particles have steadily grown in interest for synthetic bone composite structures. Nano and micro sized calcium phosphates especially are of interest because of the osteoinductive behavior of calcium phosphate. Engineered composites incorporating polymers and ceramics, such as poly l-lactic acid (PLLA)/β-TCP, for bone tissue regeneration have been well investigated for their proliferative and osteoinductive abilities. Limited research has been done to thoroughly investigate the effects of various sized β-TCP particles on human mesenchymal stem cell behavior. Foreign bodies are known to elicit an inflammatory and cytotoxic response and several nano-particles are known to elicit cytotoxic and pro-inflammatory responses of mesenchymal stem cells. In this study, the modulation of adult human adipose-derived mesenchymal stem cell (hASC) behavior exposed to β-TCP, as functions of particle size, content and composition in a polymeric-ceramic scaffold system was investigated. The objectives of this work include the development and characterization of monolithic 3-D polymeric-ceramic structures using a modified unidirectional fabrication technique to investigate the cytotoxic, pro-inflammatory and osteogenic potential of PLLA-β-TCP composite on adult human stem cells. Characterization of PLLA-β-TCP composites showed that increasing β-TCP content the compressive strength decreases. Viability of hASCs over a 7 day exposure study showed increasing cytotoxicity with respect to increasing particle concentration regardless of size, although acute (24hr) cytotoxicity was more influenced by size. qPCR was used to measure the pro-inflammatory (IL-6) expression as well as early osteogenic differentiation (hALP). Results suggest there is a modulation in stem cell behavior as a function of β-TCP particle size, concentration and composite system.

The blood-brain barrier (BBB), which protects the central nervous system (CNS) from unnecessary substances, is a challenging obstacle in the treatment of CNS disease such as Parkinsons Disease (PD). Many therapeutic agents such as hydrophilic and macromolecular drugs cannot overcome the BBB. One promising solution is the employment of polymeric nanoparticles (NPs) such as poly (lactic-co-glycolic acid) (PLGA) NPs as drug carrier. Over the past few years, significant breakthroughs have been made in developing suitable poly (lactic-co-glycolic acid) (PLGA) and poly (lactic acid) (PLA) nanoparticles for drug delivery across the BBB. Recent advances on PLGA/PLA NPs enhanced neural delivery of drugs were reviewed in the second chapter. Both in vitro and in vivo studies were included. In these papers, enhanced cellular uptake and therapeutic efficacy of drugs delivered with modified PLGA/PLA NPs compared to free drugs or drugs delivered by unmodified PLGA NPs was shown; no significant in vitro cytotoxicity was observed for PLGA NPs and PLA NPs. Surface modification of PLGA/PLA NPs by coating with surfactants/polymers or covalently conjugating with targeting ligands has been confirmed to enhance drug delivery across the BBB. Most unmodified PLGA NPs showed low brain uptake (<1%), which confirms the safety of PLGA/PLA NPs used for other purposes than treating CNS diseases. For the second part of the study, wheat germ agglutinin (WGA), a lectin was conjugated to PLGA nanoparticles (PLGA-tWGA NPs, 221 nm) to improve DAergic neuron delivery in C.elegans. PLGA-tWGA NPs did not show a significant effect on pumping rate and life span of C. elegans at low concentration (<3 mg/ml). Fluorescent studies of GFP-DAergic neurons revealed that area of GFP-DAergic neurons of worms treated with high concentrations PLGA-tWGA NPs (>3mg/ml) was significantly decreased. Number and mean intensity of GFP-DAergic neurons also decreased, but no significant difference was found compared with control group. Co-localization of the fluorescent particles with the GFP-DAergic neurons of treated worms proved targeting property of PLGA-tWGA nanoparticles to DAergic neurons. Enhanced targeted delivery of PLGA-tWGA NPs to neurons compared with tWGA and PLGA-t NPs made PLGA-tWGA NPs potential targeted neural delivery systems for the treatment of PD.

Synthesis of micro/nanomaterials within confined flow-based systems such as microfluidics has always been a promising research. However, the inability to scale up reagent volumes due to geometric constraints and pressure development within the channels at higher flow rates has limited their usage. In recent times, millifluidics has emerged as a useful technique where, apart from the synthesis, the in situ characterization of materials becomes easier. In this study, formation of morphology-controlled gold structures at different time intervals (viz. 1, 5, and 9 h) within a millifluidic chip reactor was investigated using gold chloride and dimercaptosuccinic acid (DMSA) as precursor reagents and sodium borohydride as the reducing agent. The structures formed were characterized using 3-D X-ray tomography, X-ray absorption near edge spectroscopy (XANES) and scanning electron microscopy (SEM). The X-ray tomography results show that the dimension of the gold structures vary with respect to their time of deposition within the channel. The gold structures formed at 1 h are 26 µm wide, 5 h are 55 µm wide and 9 h are 100 µm wide. However, the height of the gold structures remained relatively uniform and peaked at 27.5 µm for all the samples. The XANES results show that there are differences in the chemical nature and bonding of the structures before and after reduction with sodium borohydride. A linear combination fitting of the XANES spectra show 50% Au and 50% S with both Au-Au and Au-S bonding for the structures before reduction and 83% Au, 17% S predominantly Au-Au bonding after reduction with borohydride. The SEM of the gold structures show hemispherical shape for sample formed for 9 h, flower-shape for 5 h and polygonal-shape for the 1 h sample. The catalytic activity of these gold structures was also demonstrated through 4-nitrophenol and Ferricyanide conversion reactions. In both the conversion reactions, the gold structures formed for 9 h flow time show better catalytic performance in terms of yield with 90.5% conversion for 4-nitrophenol and 85.5% conversion for Ferricyanide.