An energy balance was developed for heated and unheated earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanism affecting pond temperature; 2) predict pond temperatures; 3) estimate the energy required to control pond temperatures, and 4) recommend efficient heating and cooling methods. PHATR (Pond Heating and Temperature Regulation), a computer program using 4th order Runge-Kutta numerical method was developed to solve the energy balance using weather, flow rate and pond temperature data. By comparing measured and modeled pond temperatures, the average difference (the average bias) was 0.5°C for unheated ponds and 2.4°C for heated ponds. The error in warm water flow measurements explained the elevated average bias for heated ponds. The dominant energy transfer mechanisms for unheated ponds were solar radiation (maximum: 55%), pond radiation (average: 35% to 42%) and longwave sky radiation (average: 28% to 34% ). The dominant energy transfer mechanisms for heated ponds were solar radiation (maximum: 50%), pond radiation (average: 25%), longwave sky radiation (average: 19%) and the 36°C water used to heat the ponds (maximum: 60%). The difference in biases when comparing three empirical evaporation equations ranged from 0.2°C to 1.9°C. The difference in biases when comparing two empirical convection equations ranged from 0.0°C to 2.1°C. The average light extinction coefficient for the ponds was 0.013 mm-1. The sensitivity analysis, used to determine how variations in input data affected the model results, showed that output varied linearly with changes in average air temperature and solar radiation. The output decayed exponentially to changes in wind speed and flow rate. Using PHATR and 40 years of weather data, the pond temperature for a 400-m3 pond was calculated for cold, hot and average years. The average pond temperature for an average year was 21.8°C. The net energy required to maintain the pond temperature at 25°C was 3.24 x 109 J/m3. Warming a 400- m3 pond 2°C/day during a typical mid-January week would require 7.64 x 1010 J over 9 days.

The inadequate removal of aconitic acid from sugar cane juice during the clarification process results in the acid contributing to processing difficulties, sucrose loss and extended down time. However, very few attempts have been made to remove the acid during normal factory operations. Batch clarification techniques were used in this study to investigate the effect of sucrose concentration, temperature, pH, time, defecant, and defecant concentration on aconitic acid removal from a synthetic juice solution. Methodology for determining the significance of each parameter to aconitic acid removal involved setting up a multiple factorial experiment looking at aconitic acid removal across all the parameters and their sublevels using the mixed linear modeling procedure in SAS (statistics analysis software) and applying results to raw juice. Results indicated that sucrose concentration, temperature and defecant concentration were the most significant parameters contributing to Aconitic acid removal, since aconitic acid removal was limited by cis-aconitic acid formation, the solubility of aconitates and competing compounds. Optimizing aconitic acid removal form synthetic juice points to reducing cis-aconitic acid formation by clarifying at low temperatures, reducing solubility of aconitates by increasing sucrose concentration and providing adequate reactants for competing compounds. Optimal conditions for aconitic acid removal from synthetic juice, when applied to raw juice resulted in a marginal increase in aconitic removal. However, prospects for increased aconitic acid removal from raw juice points to clarification of raw juice at the concentrated levels.

Carrot cubes were ohmically heated with 2 different frequencies 1 Hz and 60 Hz to evaluate change in color, texture and rehydration properties. Carrot samples were stored under 4 different relative humidity (RH) conditions 11.1 %, 32.7%, 55.7 % and 75.3 %. Experiments were conducted to monitor the textural parameters of hardness, fracturability, adhesiveness, cohesiveness and chewiness and color changes in terms of CIE color values. Results showed that the hardness, fracturability and adhesiveness of 1- Hz samples stored at 75.3 % RH were different from those at 55.7 % RH. The adhesiveness, cohesiveness and chewiness of 1-Hz samples were different from the control at 55.7 % RH. There was significant correlation between cohesiveness and chewiness and moisture content of the rehydrated samples. For the moisture content after ohmic heating a negative correlation was observed with properties of chewiness, hardness and adhesiveness. Color lightness (L*) values of rehydrated carrots decreased (i.e. became darker) with the increase in storage time. At both 1-Hz and 60-Hz the difference in the L values of fresh and rehydrated carrots was significantly different from that of the control. The degree of redness (a*) of 1-Hz rehydrated samples after 1 Hz treatment were different from the control stored at 55.7 % RH. The water absorption capacity values decreased throughout the six-day storage period for both the treated and control carrot samples. Thus there exists a great potential to enhance mass and heat transfer properties in food process engineering using ohmic heating, particularly because ohmic treatment has been shown to significantly alter rehydration, texture and color efficiencies. This study demonstrated that ohmic treatment significantly affects color, texture and rehydration properties of carrots stored under different RH environments.

Ohmic heating has been shown to affect the drying rate and texture of foods. This research was designed to determine the effect of ohmic heating on rehydration, color and texture properties of sweet potatoes. Three combinations: 60Hz, 40V, 60Hz, 60V and 1Hz, 40V were applied to ohmically heat sweet potato cubes. The ohmic treated cubes and untreated cubes or controls were stored for six days in four different %relative humidities of 11.15%, 32.73%, 57.70% and 75.32%. Results showed that there was no significant difference in the rehydration properties of ohmic treated samples and control samples. The % moisture gain varied between a minimum of 0.1% and a maximum of 40.7% in the case of ohmically treated samples and 0.71% to 32.41% for control samples. The color lightness values increased with increase in storage time for both ohmically treated and control samples. The 60Hz, 40V ohmically treated samples had less increase compared to control samples. The degree of redness (a*) and degree of yellowness (b*) values were significantly higher for ohmically treated samples during storage. A significant loss of color pigments into rehydrating water was observed during rehydration for ohmically treated samples. The 60Hz, 40V treated samples retained color and appearance compared to other treatments. Texture analysis showed that the ohmic treated samples (60H, 60V) had higher hardness, springiness and chewiness values than the control samples. At lower humidities the firmness or hardness values increased with increase in storage time. Positive correlations were obtained between the moisture content of the samples after rehydration and the hardness and chewiness values. This study demonstrated that ohmic heating played a pivotal role in retaining rehydration properties, color attributes and some of the texture attributes of the sweet potato samples when appropriate combinations of frequency and electrical field strength were used.

This research investigated the growth kinetic parameters (Ks and µmax) of the Kluyveromyces marxianus yeast strain for a batch process under aerobic and anaerobic conditions at 45oC using the Two-Liter Bioflo® 2000 Fermentors and the Orbital Shaker Bed with 250mL flasks (New Brunswick Scientific). This yeast strain was grown in twelve different glucose media concentrations (Anderson et al. 1986), ranging from 200 mg/L to 80,000 mg/L. Several analytical techniques were used, such as COD measurement to determine soluble and total substrate concentrations, TSS and OD measurements to determine biomass formation, HPLC measurements to determine carbohydrate concentrations, and GC measurements to determine alcohol concentrations. The growth kinetic parameters were investigated using the Monod Model which accounts for microbial growth in any environmental condition, assuming decay a constant for the microorganism negligible during the exponential growth phase. The nonlinear (the Lee equation) and linear (the Hanes and the Lineweaver-Burk equations) methods were used to estimate the kinetic parameters (Ks and µmax) for the aerobic and the anaerobic conditions. Neither the nonlinear nor the linear method succeeded with reasonable estimations for the growth kinetic parameters (Ks and µmax). The lack of information and investigation on the nonlinear and the linear models in the literature, concerning Kluyveromyces marxianus kinetic analysis initiated an investigation of these nonlinear and linear models using a mathematical simulation technique called the Monte Carlo method with the SAS (Statistical Analysis Software) program (version 9). The sweet potato waste was used as substrate for a preliminary experiment which was designed to determine the growth kinetic parameters at 40oC, 45oC, and 50oC and the Arrhenius parameters for the Kluyveromyces marxianus yeast strain (Appendix A). This preliminary experiment used the three Two-Liter Bioflo® 2000 fermentors (New Brunswick Scientific) for a batch process under anaerobic conditions.

Many occupational groups work under adverse conditions in which their spinal columns are fully flexed under load for substantial periods of time. This study was designed to determine the response of the lumbar spine to a static load of a substantial duration under a range of load magnitudes. The impact of static loads of 20, 40 and 60N were applied over 30 min flexion, 10 min rest, and 30 min flexion (for a total of one hour exposure) followed by a 7 h rest. Lumbar viscoelastic creep (laxity) and reflex electromyographic (EMG) activity were monitored over both flexion periods and the 7 h rest period. It was found that 10 min of rest was not sufficient for complete recovery of the creep developed in the first 30 min of flexion resulting in a large cumulative creep at the end of the work-rest session. Muscle activity indicated spasms during the static flexion periods and demonstrated the development of initial and delayed hyperexcitability in each of the 3 loads. Larger magnitudes of initial and delayed hyperexcitability were observed for larger loads although the differences were not statistically significant. Thus, intense periods of static flexion will result in neuromuscular disorders regardless of load magnitude. The results of the 3:1 work-rest ratio were compared with previously obtained data of a series of short static flexion periods (1:1 ratio) of the same cumulative time to determine which can best expedite the recovery of creep. Although the valuable effects of a 1:1 work-rest ratio have been documented (Sbriccoli, 2004), a 3:1 work-to-rest duration ratio was not sufficient to attenuate or prevent the development of any of the components of a neuromuscular disorder and the associated microdamage and inflammation. In conclusion, a cumulative low back disorder was elicited from exposure to two 30 min static loads spaced by a 10 min interval.

A process-control temperature system was designed and developed for facilitating somatic cell research on eastern oyster Crassostrea virginica. The system consisted of sixteen independent tanks capable of individual temperature regimes controlled by a central computer. Food grade 250-L tanks were used to hold 60 oysters per tank. Each tank was equipped with heating and cooling mechanisms. Immersion heaters were used for heating and a pump and a stainless steel heat exchangers immersed in chilled water (~ 7°C) were used for cooling. Type-T thermocouples along with a CIOEXP32 multiplexer board (Measurement Computing Inc.) were used to measure water temperatures. Control was achieved via a pair of analog and digital (A/D) boards that actuated heaters and pumps through solid state relays. The performance of the system was evaluated in two experiments for studies on somatic cell proliferation in eastern oysters. In the first experiment, the system was programmed to maintain constant temperatures of 10, 15, and 20°C for a 20-day period. The system was able to maintain temperatures within ± 0.2°C. In the second experiment, diurnal fluctuations of 20 ± 1°C, 20 ± 5°C, 15 ± 1°C, 15 ± 5°C, and 15 ± 10°C were imposed. The system was able to simulate water temperatures within ± 0.2°C for regimes 20 ± 1°C, 20 ± 5°C, 15 ± 1°C. A computer program Realwire for measuring and simulating real-time water temperatures was developed using freely available public domain software called Python and GNUwget. The software was able to measure and simulate real-time water temperatures.

Louisiana's coastline has received national attention due to rapid erosion rates estimated from approximately 60 to 100 square kilometers per year. The disappearance of coastal areas jeopardizes public and private infrastructure, property values, aquatic ecosystems, and standards of living. In order to resolve the erosion problem, innovative solutions have been explored that may improve effectiveness and cost efficiency. This research involves a technology, termed an "oysterbreak," which is a bioengineered submerged breakwater. This structure promotes oysters to form a dense structure that dissipates wave energy. Since the structure is biologically dominated, initial material use is modest. The oysterbreak was evaluated through a series of experiments. Settlement patterns were analyzed by quantifying the biological fouling on the structure during its deployment in Grand Isle, Louisiana for one year. Secondly, settlement preference on materials was analyzed in a tank under various flows. To investigate further, the wave interactions with various scaled designs were also analyzed in a wave tank. The transmission, reflection, and dissipation characteristics were determined as growth occurred. Lastly, a predictive model was developed from the results. Experiments suggest that a uniform distribution pattern could be expected in the absence of predation. Also, it was shown that mortar coating was superior for oyster settlement to PVC pipe and commercially available oyster tubes. The wave tank experiments concluded that wave transmission through the structure decreased as growth occurred. It was also shown that a structure with 2 vertical slats/meter, could be used to effectively dissipate waves. The predictive model developed suggests that the oysterbreak can be used in field conditions. The model showed that after one year of growth, an oysterbreak 20 meters wide has the capacity to reduce wave energy by 70%. This prediction is consistent with other submerged breakwater designs. The results of these experiments will be used to design, deploy and monitor full scale oysterbreaks.

Many biochemical processes in which DNA and other nucleic acids participate are central to functions in both living cells and in molecular biology assays. While many compounds have been used to regulate the activity of DNA, these strategies are limited to the aqueous-based diffusion of the activator to the target DNA molecule. An improvement to the induction of DNA bioactivity is to move to a light-based modulation. This research demonstrates a light-based technique using a photo-cleavable cage compound to transiently inactivate DNA hybridization. Function can be restored with exposure to near-UV light, allowing for temporal control of DNA oligonucleotide (ODN) activity. This method has demonstrated the control of hybridization in molecular biology assays, and provides the framework for in vivo experimentation. A similar light-activated strategy has been shown useful in controlling expression of plasmid transgenes (Monroe 1999). By adapting this method to DNA oligonucleotides (ODNs), we have partially blocked hybridization with the cage compound (1-(4,5-dimethoxy-2-nitrophenyl)ethyl ester (DMNPE) for both phosphodiester and phosphorothioate DNA ODNs. The production and purification of DMNPE-caged DNA ODNs yields products with similar spectrophotometric properties to caged plasmids. In hybridization studies, 20-mer (20 base long) caged DNA ODNs were hybridized with complementary 30-mer molecular beacon probes, and fluorescence measurements were used to assess hybridization of native (non-caged), caged, and caged-light-exposed ODNs. Developments of the molecular beacon assays were studied to improve sensitivity of the assay to caged and caged-flashed ODN hybridization control. Results demonstrated that hybridization can be blocked and subsequently restored by light through the attachment of the DMNPE cage compound, and were further characterized with gel electrophoresis assays. ODN hybridization was restricted to as little as 2% when compared to native (non-caged) ODNs and restored to up to nearly 80% of the native (non-caged) ODN hybridization activity levels. Additional studies on adduction, purification, and characterization of the DMNPE-caged ODNs were performed to optimize their production and efficacy in controlling hybridization. These results suggest that this light-based technology can be used as a tool for the spatial and temporal regulation of hybridization-based DNA bioactivity, including applications with antisense ODNs as a form of controlled gene therapy.

Bird predation is a major problem in aquaculture. A novel method for dispersing birds is the use of a vehicle that can sense and chase birds. Image recognition software can improve their efficiency in chasing birds. Three recognition techniques were tested to identify birds 1) image morphology 2) artificial neural networks, and 3) template matching have been tested. A study was conducted on three species of birds 1) pelicans, 2) egrets, and 3) cormorants. Images were divided into 3 types 1) Type 1, 2) Type 2, and 3) Type 3 depending upon difficulty to separate from the others in the images. These types were clear, medium clear and unclear respectively. Image morphology resulted in 57.1% to 97.7%, 73.0% to 100%, and 46.1% to 95.5% correct classification rates (CCR) respectively on images of pelicans, cormorants and egrets before size thresholding. The artificial neural network model achieved 100% CCR while testing type 1 images and its classification success ranged from 63.5% to 70.0%, and 57.1% to 67.7% while testing type 2 and type 3 images respectively. The template matching algorithm succeeded in classifying 90%, 80%, and 60% of Type 1, Type 2 and Type 3 images of pelicans and egrets. This technique recognized 80%, 91.7%, and 80% of Type 1, Type 2, and Type 3 images of cormorants. We developed a real time recognition algorithm that could capture images from a camera, process them, and send output to the autonomous boat in regular intervals of time. Future research will focus on testing the recognition algorithms in natural or aquacultural settings on autonomous boats.