Abstract Huge progress has been made in the development of three dimensionally printed tissue structures. With the use of cells, three dimensional printers, and CAD drawing software, donor identical structures can be fabricated. However, cell scaffolds currently lack significant mechanical integrity which can result in reduced cellular survival, attachment, and nutrient delivery. For this reason, multiple strategies have been developed to increase and improve mechanical stability within engineered constructs without having to sacrifice cell viability. The hypothesis of this paper was that incorporating Perfluorotributylamine (PFTBA), a greenhouse gas, with single walled carbon nanotubes (SWCNT), a allotrope of carbon with a cylindrical nanostructure, into an alginate scaffold will not only increase mechanical integrity but also cell survival. The following objectives were proposed: 1. Fabricate and characterize cell laden scaffolds of alginate and 2. Assess the addition of perfluorotributylamine and various concentrations of carbon nanotubes inside of cell laden scaffolds of alginate. Three configurations of perfluorotributylamine and carbon nanotubes were explored in an effort to maximize mechanical properties and cytocompatibility. Perfluorotributylamine was combined with gelatin from bovine skin and phosphate buffered solution to form a PFTBA emulsion. This emulsion was added to each alginate scaffold to encompass 5% of the entire alginate scaffold. Single walled carbon nanotubes were added in increasing concentrations to have four scaffolds, one control, 0 µg/ml, .1 µg/ml, and 1 µg/ml. The results of this study indicate that the configuration of 5% PFTBA emulsion + 1 µg/ml SWCNT + alginate, provided the best cell viability results; Picogreen fluorescence of 8532, excellent viability in live/dead stain, and sufficient morphological features while the control scaffold, containing alginate only, provided the best mechanical properties after a 7 day period. The results contradict the hypothesis that mechanical properties will increase with increasing SWCNT concentration, but support the hypothesis of improved cell viability with the incorporation of PFTBA emulsion to increasing SWCNT concentration.

This study investigated the thermal performances of platinum particles when coupled on a steel support, under the application of a radio frequency (RF) field. Platinum nanoparticles were reduced on the surfaces of type-316 stainless steel balls, based on published methods of Pt reduction from chloroplatinic acid. Alternatively, 1wt. % Pt/Al2O3 commercial catalyst pellets were mixed with stainless steel balls and investigated for hydro-deoxygenation of pyrolysis oil from pine sawdust biomass. The catalysts were placed inside an electric insulator tube suspended within a looping copper coil connected to the induction heater, and heated at different power levels. An infrared camera was utilized to record the surface temperature profile during heating of Pt-coated balls and non-coated balls. Pt particles deposited onto silica beads showed no surface heating when placed inside an RF field. The Pt-coated steel systems, however, showed rapid heating of the surfaces following a first order response. The catalysts were characterized via SEM/EDX, XPS and XRD. Preliminary upgrading tests using these Pt-steel balls did not indicate any effect. The lack of catalytic activity was attributed to the limited surface area per unit volume of the Pt coating due to the large sizes and non-porous structure of the steel balls. For the catalytic upgrading experiment with the use of the Pt/Al2O3 commercial catalyst pellets mixed with steel balls, heating of the catalyst bed with the induction heater was compared with a conventional method of heating using electric tape around the catalyst bed reactor. Partial deoxygenation was successfully achieved in the catalytic upgrading of pyrolysis oil using Pt/Al2O3 pellets mixed with steel balls at 234°C, with the use of the induction heater. The molar O/C ratio of the oil decreased from 1.36 to 0.51. No deoxygenation was observed using the conventional heating method with the electric tape under identical conditions as both carbon and oxygen appeared to be removed at approximately equal rates, with the carbon being deposited in the form of coke onto the catalyst instead of being recovered in the liquid.

A method for collecting dinitrogen gas emissions from open pond waste treatment systems was developed. The method was critically tested in a laboratory for sources of air contamination to ensure reliable gas measurements. A laboratory experiment was done to estimate the rate at which dissolved dinitrogen would be stripped out of solution due to non-dinitrogen bubbles rising through the water column. A volumetric mass transfer coefficient for the process was estimated for clean water. The gas collection method was implemented in a partially aerated lagoon treatment system for dinitrogen and methane gas sampling. The volumetric mass transfer coefficient found in the laboratory for clean water was adjusted to compensate for field gas production rates, temperatures and wastewater quality to estimate the rate of stripped dinitrogen from the partially aerated lagoon. The estimated rate of stripped dinitrogen was subtracted from the total measured dinitrogen flux to estimate the dinitrogen produced biologically. Results from laboratory testing revealed that dinitrogen can be measured with low amounts of dinitrogen atmospheric contamination (0.57% N₂) and the preliminary field results suggest that biological denitrification did occur at this lagoon treatment system.

Turfgrass is a major part of the landscape in North Carolina with its acreage equal to 44% of the stateâs harvested crop acreage. Proper irrigation of residential, industrial and commercial turf areas is required to ensure healthy and acceptable turf quality. With increasing competition for water resources and better turf quality, an efficient irrigation control technology is essential in meeting the dual goals of water conservation and turf quality. The objective of the research was to compare two general types of commercially available irrigation control technologies; one based on estimates of evapotranspiration (ET) and the other based on feedback from soil moisture sensors. Water application and turf quality resulting from using these technologies were compared to results from using a standard time-based irrigation schedule. The study also incorporated the effect of irrigation frequency. The experimental area, located at North Carolina State University Lake Wheeler Turf Field Laboratories, Raleigh, North Carolina, consisted of forty 4-m x 4-m plots established to âConfederateâ tall fescue (Festuca arundinacea Schreb) using sod. There were ten treatments combining control type and watering frequency (3 technologies x 3 frequencies + 1 on-demand technology) with four replicates in a randomized complete block design. Technologies included three systems: a time-based system, a soil-moisture-based âadd-onâ system, an ET-based system each with three frequencies: once per week, twice per week and seven days per week irrigation, and a soil-moisture-based âwater on-demandâ system which was allowed to schedule irrigation everyday. Rain sensors were connected to the timer-based and ET-based systems to prevent irrigation in case of rainfall. The add-on soil-moisture-based system applied the least amount of water while the ET-based technology applied the most water averaged across frequencies. Once a week irrigation frequency applied the least amount of water, and daily irrigation frequency applied the most when averaged across all technologies. Minimally acceptable turf quality was met by all the treatments when averaged over the duration of the study period, although during the last month of the study some technologies, especially the timer-based and add-on systems had noticeably drought stressed plots. In general, the ET-based system and the water on-demand system had the best turf quality. The water on-demand system resulted in the best combination of water use efficiency and turf quality. Canopy temperatures were measured once a week and there were significant differences in canopy temperature among treatments averaged over the season. The ET system plots had the lowest canopy temperature while the add-on system plots had the highest canopy temperature. Also there was no significant difference between mean weekly reference ET estimates from an atmometer and Penman-Montieth reference ET estimates using a weather station at the site.

The rock cross vane, an in-stream boulder structure, consists of a U-shaped weir with the apex upstream at bed elevation and upward sloping arms that tie into downstream banks. The structure provides grade control, bank protection and scour pool development via a protected drop and arms that turn flow away from the banks. A physical model was used to measure the velocity distribution changes caused by a range of geometric configurations of the structure. Results showed linear and quadratic effects of drop ratio, cross product effects of drop ratio and arm angle, drop ratio and arm slope, and arm angle and arm slope on the velocity ratio (the average center velocity to the average outer velocity) of a cross section located two bankfull widths downstream of the drop. The Rock Cross Vane Rapid Assessment Tool (RCV-RAT) was developed to rate rock cross vane failures and assess the causes of structure weakness on NC stream restoration projects. Failure ratings were analyzed for significant correlations to project parameters, class effects of project, and correlations between dependent variables (alpha =0.05). Of the 120 rock cross vanes observed, 109 had at least one incidence of failure ranging from slight to extreme. From this data, an FMEA was developed to compare the risks of the various modes of failure for the rock cross vane and to adapt the FMEA for use in North Carolina stream projects. It was concluded that sufficient drop is necessary for scour pool development, while steep, narrow arms leading to a constricted flow area minimally contribute to scour pool development and may risk bank instability at the structure and at downstream banks. Rock cross vanes that can tolerate rapid lateral migration of the stream post-construction should be developed and tested due to the observed problems of structure side cutting. The final chapter reviews literature for the main effects of stream restoration on benthic macroinvertebrate communities and the expected return of benthic macroinvertebrate communities post-restoration to address what impacts the rock cross vane might have on benthic macroinvertebrates and to recommend practices that might reduce these impacts.

Environmentally sound treatment of by-products in a value-adding process is an ongoing challenge in animal agriculture. Thermophilic anaerobic digestion of wastes originating from agricultural production and animal processing represents a potential waste treatment technology to address environmental concerns such as odor emissions and removal of pathogenic microorganisms, while at the same time producing renewable energy (biogas) as a by-product. However, thermophilic digestion is subject to inhibition by ammonia and long chain fatty acids (LCFA), both of which are prevalent in manure and animal processing wastewater. Several swine manure collection methods under development separate the urine from the feces, which creates the opportunity to operate a digester on feces only, greatly reducing the ammonia load to the digester. One objective of this study was to determine whether operation on feces only would yield significant performance improvements for a thermophilic anaerobic digester operating on swine waste. Effluent from a continuously stirred tank reactor (CSTR) was used as the inoculum for batch tests in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine:feces ratio and double the as-excreted urine:feces ratio). Inocula were acclimated to these same urine:feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained TKN concentrations up to 7.20 g-N liter-1. The sludge collected from the dissolved air flotation (DAF) wastewater treatment process in swine processing facilities is an example of a high-lipid substrate containing potentially inhibitory levels of LCFA. A second objective of this study was to determine the fundamental performance parameters for thermophilic anaerobic digestion of DAF sludge. Testing in a semi-continuous stirred tank reactor and in batch reactors was conducted to determine substrate degradation rates and biogas yield. Stable operation could not be achieved using pure DAF sludge as a substrate, possibly due to inhibition by long chain fatty acids or to nutrient deficiencies. However, a 1:1 ratio (w/w, dry basis) of DAF sludge and swine manure (feces only), resulted in stable and productive digester operation. In the semi-continuous stirred reactor at 54.5ï°C, a hydraulic residence time of 10 days, and an organic loading rate of 4.68 gVS/day/L, the methane production rate was 2.19 L/L/day and the specific methane production rate was 0.47 L/gVS (fed). Maximum specific methanogenic activity (SMA) in batch testing was 0.15 mmolesCH4 hr-1 gVS-1 at a manure/DAF substrate concentration of 6.9 gVS liter-1. Higher substrate concentrations cause an initial lag in methane production, possibly due to long chain fatty acid or nitrogen inhibition.

The objectives of this project were to develop operating conditions for a bench-scale sequencing batch reactor to match the design of a full-scale sequencing batch reactor system for treating swine waste and to determine the effects of continuous, low oxygen versus cyclic aeration schemes on sequencing batch reactor system performance. The low aeration technique was intended to develop conditions for low oxygen nitrification and simultaneous nitrification and denitrification so that a comparison could be made to a typical cyclic aeration reactor for biological nitrogen and phosphorus removal. The performance of the two reactor configurations was measured by the settling efficiency, mass removal efficiency, and accumulation of chemical oxygen demand (COD), suspended solids (SS), total Kjeldahl nitrogen (TKN), and total phosphorus (TP). The performance of the reactors did not meet expectations due to excessive loading and source inconsistency. Operational changes to the solids wasting mechanism and to the cyclic aeration system were made during the experiment in an attempt to stimulate reactor performance, which provided insight into the responses of the two types of reactors to these changes. The performance of the continuous aeration reactors met or exceeded the performance of the cyclic aeration reactors, while receiving a 73% lower supply of oxygen. The results support the potential for equipment and energy savings by utilizing low-oxygen continuous aeration for the treatment of swine waste with sequencing batch reactors.

The objective of this study was to investigate the effectiveness of sulfuric acid, sodium hydroxide, hydrogen peroxide, and ozone pretreatments for conversion of cotton stalks to ethanol. Sulfuric acid, sodium hydroxide, and hydrogen peroxide at concentrations of 0.5, 1, and 2% (w/v) were used to pretreat ground cotton stalk samples at a solid loading of 10% (w/v). Treatment temperatures of 90 degrees Celsius and 121 degrees Celsius at 15 psi were investigated for residence times of 30, 60, and 90 minutes. Ozone pretreatment was performed in the liquid phase at 4 degrees Celsius with constant sparging. Lignin, carbohydrate, and moisture content analyses were performed on the pretreated solids. The pretreated solids from sulfuric acid, sodium hydroxide, and hydrogen peroxide pretreatment (at 2%, 60 min, 121C/15psi) showed significant lignin degradation and/or high sugar availability and hence were hydrolyzed by cellulases from Trichoderma reesei and â-glucosidase at 50 degrees Celsius. The results showed that time, temperature and concentration were all significant (p is less than or equal to 0.05) factors in delignification for NaOH and xylan removal for H2SO4. Sulfuric acid pretreatment resulted in the highest xylan reduction (95.23% for 2% acid, 90 min, 121C/15psi) during pretreatment and the lowest cellulose to glucose conversion during hydrolysis (23.85%). Sodium hydroxide pretreatment resulted in the highest level of delignification (65.63% for 2% NaOH, 90 min, 121C/15psi) and the highest cellulose conversion (60.8%). Hydrogen peroxide pretreatment resulted in significantly lower (p is less than or equal to 0.05) delignification (maximum of 29.51% with 2%, 30 min, 121C/15psi) and cellulose conversion (49.8%) than sodium hydroxide pretreatment, but had a higher (p is less than or equal to 0.05) conversion than sulfuric acid pretreatment. Ozone pretreatment showed no significant changes in lignin, xylan, or glucan contents with increasing time. Quadratic models using time, temperature, and concentration as numeric variables were developed to predict xylan reduction for H2SO4 pretreatment and lignin reduction for NaOH pretreatment. In addition, linear models relating a modified severity parameter (log Mo) combining the pretreatment parameters with xylan or lignin reduction were developed and resulted in R-squared values of 0.89 and 0.78, respectively.

Current tobacco baling technology utilizes hydraulic power to press tobacco into bales. The high system pressures at which hydraulic systems operate pose a risk to workers. Hydraulic systems are costly and hydraulic oil leaks contaminate baled tobacco. A pneumatically driven, vertically oriented, multi-stroke baler was designed as an affordable alternative to current hydraulic balers. Pneumatics was chosen due to the lower system operating pressure and absent risk of tobacco bale contamination. The transmission of power was achieved through a reversible pneumatic gearmotor turning left and right hand acme threaded rods coupled together to form a powerscrew. The plunger was driven by a scissor-jack design and was used to take advantage of the non-linear force response of tobacco. The scissor-jack was driven by acme nuts traveling along the acme rod of the powerscrew. The baler was tested with burley tobacco grown during the 2007 season at the Central Crops Research Station in Clayton, NC. The compressive force and plunger displacement was measured for each bale produced. These readings were used to determine the compressive force as a function of plunger travel and the compressive force as a function of bale density. The baler required 3-4 presses to produce burley bales roughly 42 inches cubed and weighing approximately 500-600 pounds.

Ammonia emission from animal feeding operations has potential negative impacts on the environment and public health and it also reduces the nutrient value of animal waste. When conditions are not suitable for land application, broiler cake (or litter) may be stored in stockpiles which may contribute to ammonia emission. In this study, summer and winter ammonia emission factors from broiler cake stockpiles stored in a naturally ventilated shed were developed. The lab experiment measured relative ammonia emissions as affected by type of cover and depth of cake. Scrubbers were used to measure ammonia concentration both in the field and lab studies. In the field, the integrated horizontal flux (IHF) method and Fickâs law of diffusion were used to determine ammonia emissions due to forced and natural convections, respectively. The ammonia emission due to natural convection was <0.01% of total emission. However, it may be necessary to calculate emissions based on concentrations measured only during conditions of forced convection. In summer, the estimated total ammonia-N loss was 0.8 % of total N. In winter, the total ammonia loss was 1.4 % of total N during the first 7 d and 2.5 % for the whole 15-d period. The estimated average daily ammonia emission factor in summer (7 d) was 24.5 g NH3-N/m3-d of cake or 7.0 g NH3-N/AU (500 kg LW)-d. The estimated daily ammonia emission factor for the first 7 d in winter was 35.6 g NH3-N/m3âd or 42.5 g NH3-N/AU-d. The total ammonia lost during the 15-d winter study was 33.8 g NH3-N/m3-d or 40.2 g NH3-N/ AU-d. Ammonia losses from the tarp covered cake were significantly lower than the control and double depth treatments by 45% and 49%, respectively, at the end of study. Ammonia losses (g/m3) are lower from stockpiles with lower surface area per unit volume.