Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-06, Section: B, page: 3928. Adviser: Yuanhui Zhang. Includes bibliographical references (leaves 132-146) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph. D.)--Columbia University, 1920. / Vita. "Selected bibliography for farm shop work": p. 79-82.

The general objective of this work was to evaluate the effectiveness of a Laser Measurement Systems (LMS) mounted on an agricultural vehicle at detecting foreign objects in standing crops such as Hay, Wheat, Soy, and Oats. More specifically, to evaluate the effectiveness of various algorithms and evaluating the affect of various test parameters. A SICK LMS 291-S14 scanner was placed on an agricultural tractor to scan different standing crops in which standard test objects were placed. A high rate of detection was found for objects that were significantly taller than crops. Crop density or foliage cover had a negative impact on the detection rate for shorter test objects. Increasing vehicle speed was also found to reduce detection rates due to lower field scan resolution. The average height and density methods had greater success rates of 72.4% and 49.4%. The discontinuity and connectivity methods had a success rate of 20.6% and 18% respectively. This system, with the conjunction of other safety systems, may be useful for ensuring safe field operation of autonomous agricultural vehicles.

The use of co-substrates can significantly enhance biogas production from manure while helping to treat and dispose of high carbon organic wastes from the food processing industry and municipalities. This thesis will focus on the experimental setup and results collected at the University of Guelph -- Campus d'Alfred from a series of Biochemical Methane Potential assays and six 30 L semi-continuous anaerobic digesters operating under mesophilic conditions. The co-substrates investigated during the study include: corn silage, canola meal, whey, glycerine and dissolved air floatation sludge. The use of liquid dairy manure proved to be beneficial for the anaerobic digestion process by supplementing necessary buffering capacity, nitrogen, micro and macro elements for the co-digestion of high carbon organic wastes. Biochemical Methane Potential assays of the co-substrates increased the biogas yield from 5 to 250%. When these co-substrates were elaborated in semi-continuous pilot digesters, volumetric biogas production increased two to three-folds in relation to liquid dairy manure.

No description available.

A laboratory-scale, horizontal, continuous, countercurrent solid-liquid extractor was constructed and used in experiments to determine: (1) axial dispersions in solid phase, (2) convective mass-transfer coefficients, (3) axial dispersions in liquid phase, and (4) extraction yields and solute concentration profiles in liquid and solid phases at various stripping factors, and Fick's numbers. Exhaustively extracted and sucrose-infused roasted and ground coffee with a narrow particle size range was used as solid carrier in experiments to determine axial dispersions in the liquid phase, extraction yields, and concentration profiles. All experiments were carried out at room temperature, i.e. between 17$\sp\circ$C and 23$\sp\circ$C. The solid-phase superficial axial dispersion coefficients ranged between 8.37 $\times$ 10$\sp{-6}$ m$\sp2$/sec and 3.85 $\times$ 10$\sp{-6}$ m$\sp2$/sec, and the corresponding 1/Pe for the solid phase were between 0.0050 and 0.0065. At such low 1/Pe, the effect of solid-phase axial dispersion on extraction efficiency is insignificant. The measured convective mass-transfer coefficients ranged between 2.6 $\times$ 10$\sp{-5}$ m/sec and 5.2 $\times$ 10$\sp{-5}$ m/sec, and corresponding mass transfer Biot numbers were between 500 and 1100. High axial dispersion in liquid phase was obtained by using liquid recirculation to examine the effects of liquid-phase axial dispersion on extraction efficiency. Liquid-phase axial dispersion coefficients increased 4.2 to 11.6 times when recirculation was used, and other flow conditions were maintained constant, and extraction yields decreased by 1.75% to 4.83%. Diffusion partial differential equation solutions which account for liquid-axial dispersion can be used to improve predictions of extraction yields and concentration profiles. Experimental yields ranged between 87.0% and 101.7% as high as the predicted yields. Major factors which probably contributed to experimental yields being lower than predicted yields were: (1) partial bypassing of liquid due to cross-sectional nonuniformity in solid bed packing, and (2) decreases of mass-transfer driving force due to cling. Solute concentration profiles predicted agreed well with experimental data when the Fick's number (Fo) was small, and average discrepancies of 7.4% occurred at high Fo.

Improvements in the external color of Regreened 'Valencia' oranges were studied using ethylene gas. Twelve hour cycles of gassing were followed by the restoration of normal air concentrations with high humidity. Two temperatures, 14°C and 22°C were used with ethylene concentrations of 5, 10 μl/l as well as normal generated ethylene concentration in air for two weeks. The reflectance of the fruit was measured to indicate chlorophyll concentration changes. Chroma measurements were used to mimic the human eye response. The oranges treated at 22°C with either 5 or 10 μl/l ethylene gas lost their chlorophyll (greenness) and gained orange pigment (redness). Brightness increased more in the 10 μl/l ethylene than in the 5 μl/l concentrations. At 5 μl/l little evidence of stem-end decay was observed which indicates senescence was not accelerated. Some stem-end decay was observed in oranges treated with 10 μl/l of ethylene at 22°C an indication that shelf life had been reduced because of the treatments.

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Wenqiao Yuan / Biodiesel production and utilization has been increasing rapidly worldwide in recent years. A main challenge in the commercialization and public acceptance of biodiesel is its quality control. This work reports the use of infrared spectroscopy to monitor biodiesel quality through the development of models to predict (1) the blending level of biodiesel in biodiesel-diesel mixtures, (2) the fatty acid profile of biodiesel fuels derived from various lipids, and (3) the concentration of most common impurities present in biodiesel including water, glycerol, methanol and triglycerides. Regressions based on near-infrared (NIR) spectroscopy were developed for relatively inexpensive and rapid on-line measurement of the concentration and specific gravity of biodiesel-diesel blends. Methyl esters of five different oils—soybean oil, canola oil, palm oil, waste cooking oil, and coconut oil—and two different brands of commercial-grade No. 2 on-highway diesel and one brand of off-road No. 2 diesel were used in the calibration and validation processes. The predicted concentration and specific gravity of the biodiesel-diesel blends were compared with the actual values. The maximum and average root-mean-square errors of prediction (RMSEP) of biodiesel concentration were 5.2% and 2.9%, respectively, from the biodiesel type-specific regression. For the general regression, the RMSEP were 3.2% and 0.002 for biodiesel concentration and specific gravity predictions, respectively. Five different models were developed to determine the concentration of methyl palmitate (C16:0), methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2), and methyl linolenate (18:3) present in biodiesel. Using the NIR range a set of models based on four different types of biodiesel was developed. The maximum RMSEP was 0.553% when the models were validated with biodiesel samples that were used in the calibration, however, prediction accuracy of the model under external samples was poor, therefore, a new set of models was proposed. For this case, six different types of biodiesel were used. The models developed for C18:1, C18:2 and C18:3 presented good accuracy on prediction. However, for C16:0 and C18:0, additional work was necessary to reach reasonable accuracy in prediction. Three sub models for specific ranges of concentration (low, medium, and high) were developed. The RMSEP was reduced from 2.98% to 1.51% for the C16:0 and from 2.33% to 0.56% for C18:0, when the sub-models were validated under internal and external samples. Similar procedures were followed to develop regression models based on mid infrared (MIR) spectra. The RMSEP for C16:0, C18:0, C18:1, C18:2, and C18:3 were 0.83%, 0.37%, 1.45%, 1.59%, and 0.84%, respectively. Predictions using MIR spectroscopy models were better than those obtained with NIR spectroscopy models for the C16:0 and C18:0 models. The most common impurities present in biodiesel from production processes, including methanol, free glycerol, triglycerides, and water, were determined by infrared methods using NIR and MIR spectra and partial least square regression (PLSR) methods. The models were developed in two different approaches, one was when a single impurity was present and the other was when all impurities were present. In the single impurity models, the maximum RMSEP obtained in the NIR and MIR models were 647 mg kg[superscript]-1 and 206 mg kg[superscript]-1, respectively. The models for methanol, glycerol, and water performed better using the NIR data. For the triglycerides model, MIR worked better. Only NIR data were used to develop the models for samples with all impurities. Data pre-treatment (Savitzky-Golay second derivative) was necessary to achieve reasonable accuracy in the predictions in this type of models. The maximum RMSEP was 932 mg kg[superscript]-1 presented in the model for triglycerides. The best performance was obtained in the model developed to predict methanol concentration in biodiesel with RMSEP of 177 mg kg[superscript]-1 when all listed impurities were presented. The feasibility of using NIR and MIR spectroscopy to monitor biodiesel quality was demonstrated in this work. The developed method was accurate, rapid, convenient, yet inexpensive to determine some important characteristics of biodiesel, such as biodiesel blending level in biodiesel-diesel mixtures, the fatty acid profile of biodiesel, and impurities present in the fuel.

Monitoring the nutrient dynamics in the nutrient solutions of hydroponically-grown sweetpotato plants gave the following results. (1) Monitoring the concentrations of critical individual chemical species over time in the hydroponic solution would allow for optimal nutrient management: (a) While the time variation in the Electrical Conductivity (EC) level of a hydroponic solution could suggest normal nutrient uptake, nitrate uptake inhibition, or increased nitrate uptake, the time variation in EC levels could not identify which specific nutrient species were being inhibited or increased in their uptake; (b) Even when the total nitrate assimilation per plant increased over time, the specific nitrate uptake over time actually decreased significantly and correlated well with the saturation of average growth rate, justifying the addition of nitrogen in the solution to achieve optimal growth during the plant's vegetative phase; (c) Doubled-N by ammonium resulted in the significant suppression of the uptake of nitrate and potassium as well as calcium, phosphorus, magnesium, iron and boron, among others; (d) Under doubled-N by nitrate, approximately twice as much nitrate was taken up from the solution relative to the control, indicating that the uptake of nitrate was nitrate-concentration-dependent; (e) Under doubled-N by nitrate, the uptake of potassium was unaffected; and (f) Doubled-K, designed to initiate sweetpotato rooting, significantly suppressed nitrate uptake as desired and kept the potassium uptake unaffected. (2) The fairly reasonable regularity of time variation of EC level and nutrient uptake would allow for mathematical modeling, useful for biomass prediction and stress diagnostics: (a) EC modeling over time by exponential fits resulted in reasonably acceptable r-squares under doubled-N by nitrate treatment and the control condition; (b) EC changes in the standard solution provided reasonable inverse correlation with the plant's average growth rate; (c) Exponential fitting of nitrate concentrations over time resulted in reasonable r-squares both for the doubled-N by nitrate treatment and the control condition; and (d) Under the doubled-K treatment, nitrate uptake was significantly suppressed, so that the resulting variation in nitrate concentration over time deviated significantly from that for the control condition or even that for the doubled-N by nitrate treatment, indicating physiological stress for the plants.

The assessment of environmental degradation from farming practices has received recent attention due to the concern for sustainable agriculture. The United States Department of Agriculture and the Environmental Protection Agency have set forth the Unified National Animal Feeding Operation Strategy to protect the nation's water resources from contamination. The Unified Animal Feeding Operation Strategy requires that field application of manure, a common fertilization method and manure disposal practice, may not exceed crop nutrient needs. This requirement necessitates studies to determine how the multiple variables involved interact so that farmers may comply with the regulation. In this research, the effects of the application of manure, both fresh and composted, on a production alfalfa (Medicago sativa L.) field was examined. Manure and compost were applied to a production alfalfa field to determine the impact on alfalfa yield, soil nutrient content, and the potential for nitrate leaching. A conventional "no nitrogen added" treatment was also maintained as a control. Manure and compost were applied after each harvest in amounts such that the amount of nitrogen removed in the alfalfa harvest was replaced with the same amount of nitrogen in manure or compost. Application rates varied from 35 to 476 kg nitrogen ha⁻¹ after each harvest. It was found that the finer particles of the compost incorporated into the soil profile better than the chunky form of the manure. Soil analysis down to 150 cm depth showed that the compost treatment plots contained nearly 3000 kg total nitrogen ha⁻¹, the manure plots contained about 1750 kg ha⁻¹, and the no nitrogen plots had approximately 1400 kg ha⁻¹. Final PO₄-P soil analysis revealed that compost plots contained about 125 kg PO₄-P ha⁻¹, manure plots had approximately 115 kg ha⁻¹, and no nitrogen plots had only 20 kg ha⁻¹. Alfalfa yield did not vary between treatments throughout the one and a half year study. Also, no detectable nitrate or phosphate was found in the leachate collected from each of the treatments.