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Bioresource and Agricultural Engineering

2004

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Full-Text Articles in Engineering

Synthesis And Characterization Of Starch Acetates With High Substitution, Yixiang Xu, Vesselin Miladinov, Milford A. Hanna Dec 2004

Synthesis And Characterization Of Starch Acetates With High Substitution, Yixiang Xu, Vesselin Miladinov, Milford A. Hanna

Industrial Agricultural Products Center: Publications and Information

Acetylation of high-amylose (70%) maize starch to high degree of substitution (DS) was studied by reacting starch with acetic anhydride using 50% aqueous NaOH as the catalyst. DS increased with increasing reaction times and increasing ratios of acetic anhydride to starch. Reaction efficiency (RE) increased with longer reaction times and decreased with increases in the ratios of acetic anhydride to starch for extended reaction times. Increasing the amount of NaOH increased both DS and RE. A series of starch acetates with DS values of 0.57-2.23 were prepared and their crystalline structures, chemical structures, thermal stability, and morphological properties were investigated. …


Rapid Field Evaluation Of Drip And Microspray Distribution Uniformity, Charles M. Burt Nov 2004

Rapid Field Evaluation Of Drip And Microspray Distribution Uniformity, Charles M. Burt

BioResource and Agricultural Engineering

The Cal Poly ITRC irrigation evaluation programs have been widely used to assess the global distribution uniformity (DU) of drip and microsprayer irrigation systems. The field procedures and formulas used in the program are presented in this paper. The system DU is estimated by mathematically combining the component DU values. DU components include pressure differences, "other causes" (such as manufacturing variation, plugging, and wear), unequal drainage, and unequal application rates. Results are presented from evaluations by several entities, including Cal Poly ITRC. Cal Poly evaluations of 329 fields provided an average DUlq of 0.85 for drip and 0.80 for …


An In Situ Cell For Characterization Of Solids By Soft X-Ray Absorption, Ian J. Drake, Teris C. N. Liu, Mary Gilles, Tolek Tyliszczak, A. L. D. Kilcoyne, David K. Shuh, Richard A. Mathies, Alexis T. Bell Oct 2004

An In Situ Cell For Characterization Of Solids By Soft X-Ray Absorption, Ian J. Drake, Teris C. N. Liu, Mary Gilles, Tolek Tyliszczak, A. L. D. Kilcoyne, David K. Shuh, Richard A. Mathies, Alexis T. Bell

US Department of Energy Publications

A cell has been designed and fabricated for in situ characterization of catalysts and environmental materials using soft x-ray absorption spectroscopy and spectromicroscopy at photon energies above 250 eV. “Lab-on-a-chip” technologies were used to fabricate the cell on a glass wafer. The sample compartment is 1.0 mm in diameter and has a gas path length of 0.8 mm to minimize x-ray absorption in the gas phase. The sample compartment can be heated to 533 K by an Al resistive heater and gas flows up to 5.0 cm3 min−1 can be supplied to the sample compartment through microchannels. The …


Seasonal Aeration Rates For The Eastern United States Based On Long-Term Weather Patterns, Michael D. Montross, Samuel G. Mcneill, Thomas C. Bridges Sep 2004

Seasonal Aeration Rates For The Eastern United States Based On Long-Term Weather Patterns, Michael D. Montross, Samuel G. Mcneill, Thomas C. Bridges

Biosystems and Agricultural Engineering Faculty Publications

Most aeration fans are sized to produce a minimum airflow rate of 0.1 m3/min/t (0.1 cfm/bu) in on-farm grain storage structures. At this airflow rate a significant amount of time is required to move a cooling front completely through a bin. The desired grain temperature and prevailing weather conditions will have a significant effect on required fan size. Thirty years of weather data were analyzed for the eastern United States to determine the amount of time available in temperature windows between 0 to 15.C and 0 to 17.C. Contour maps were generated with ArcMap 8.3 for the percentage …


Vertical Wall Loads In A Model Grain Bin With Non-Axial Internal Inserts, Marek Molenda, Michael D. Montross, Jozef Horabik, Sidney A. Thompson Sep 2004

Vertical Wall Loads In A Model Grain Bin With Non-Axial Internal Inserts, Marek Molenda, Michael D. Montross, Jozef Horabik, Sidney A. Thompson

Biosystems and Agricultural Engineering Faculty Publications

A study was conducted to estimate the degree of load asymmetry in a bin with non-axial internal inserts. Internal inserts in the form of an annulus segment were attached to the wall, and their influence on vertical wall loads during centric filling and discharge in a model bin were measured. Wall and floor loads were measured in a corrugated-wall model grain bin with a diameter of 2.44 m and a height of 7.3 m filled with soft red winter wheat to a depth of 6.7 m (height-to-diameter ratio of 2.75). Tests were conducted with inserts that extended circumferentially 30°, 60°, …


An Undergraduate Engineering Curriculum For Agri-Industrial Facility Designers, David R. Bohnhoff, Sundaram Gunasekaran, Gregory D. Williams, Kurt A. Rosentrater Aug 2004

An Undergraduate Engineering Curriculum For Agri-Industrial Facility Designers, David R. Bohnhoff, Sundaram Gunasekaran, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Faculty of the Biological Systems Engineering Department at the University of Wisconsin-Madison are considering modifications to their undergraduate engineering curriculum that will result in graduates who are better prepared for positions as agri-industrial facility designers.


Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater Aug 2004

Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Feed mills represent an important segment of our food production system, supplying the nutritional need for animals in our meat supply system. Agri-industrial facilities such as feed mills have a number of unique design requirements that are relatively unknown. The purpose of this paper is to summarize state of the art design procedures for feed milling facilities constructed in North America. To this end, in Part I of this series, planning, life safety, and structural design criteria for these facilities are examined and relevant theory is presented. Additional resources are cited for further study of concepts. This paper should be …


Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part Ii: Process Engineering Considerations, Kurt A. Rosentrater, Gregory D. Williams Aug 2004

Design Considerations For The Construction And Operation Of Feed Milling Facilities. Part Ii: Process Engineering Considerations, Kurt A. Rosentrater, Gregory D. Williams

Kurt A. Rosentrater

Feed milling facilities represent an important segment of our food production system, because they manufacture the majority of products used to meet the nutritional needs of livestock in our meat supply chain. Agri-industrial facilities such as feed mills have a number of unique design requirements. In an effort to summarize state of the art design procedures for feed milling facilities constructed in North America, an overview of these procedures and accepted standards has been assembled. Specifically, this paper focuses on process engineering considerations. Consequently, engineers and designers should become familiar with the distinctive design process for these facilities and develop …


Design Considerations For The Construction And Operation Of Grain Elevator Facilities. Part Ii: Process Engineering Considerations, Kurt A. Rosentrater, Gregory D. Williams Aug 2004

Design Considerations For The Construction And Operation Of Grain Elevator Facilities. Part Ii: Process Engineering Considerations, Kurt A. Rosentrater, Gregory D. Williams

Kurt A. Rosentrater

Grain elevators play a key role in U.S. agriculture, and fulfill three main functions: post-harvest handling and storing of cereal grains and oilseeds, conditioning and preserving of grain, and facilitating the delivery of grain to domestic feeding and processing, as well as overseas, end-use destinations. These facilities have evolved from mere storage sites to large, high-throughput, highly automated, processing plants. This trend has been driven by the consolidation of local country elevators, which has been due, in part, to both local economic conditions as well as changing railroad regulations. Another reason has been an increased demand for grain storage space, …


Design Considerations For The Construction And Operation Of Grain Elevator Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater Aug 2004

Design Considerations For The Construction And Operation Of Grain Elevator Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Grain elevators represent a major link our food production system. To date, information about the unique design requirements of these facilities has been limited. In an effort to summarize state of the art design procedures for grain elevator facilities constructed in North America, an overview of accepted standards and procedures has been assembled. With this paper engineers should become more familiar with specific design considerations for grain handling facilities and develop appropriate references to expand their knowledge base. Educators may find this paper useful too.


Can-Based Distributed Control For Autonomous Vehicles, Matthew J. Darr, Timothy S. Stombaugh, Scott A. Shearer, John P. Fulton Aug 2004

Can-Based Distributed Control For Autonomous Vehicles, Matthew J. Darr, Timothy S. Stombaugh, Scott A. Shearer, John P. Fulton

Matthew J. Darr

Through the work of researchers and the development of commercially available products, automated guidance has become a viable option for agricultural producers. One limiting factor of many commercially available technologies is that they only automate one function of an agricultural vehicle and that their control systems are proprietary to a single machine model.The objective of this project was to evaluate a controller area network (CAN bus) as the basis of an automated agricultural vehicle. The prototype system utilized several microcontroller-driven nodes to act as control points along a system wide CAN bus. Messages were transferred to the steering, transmission, and …


Application Rate And Timing Effects On Urease Inhibitor Performance For Minimizing Ammonia Emissions From Beef Cattle Feedyards, David B. Parker, Syam Pandrangi, L. Wayne Greene, Lal K. Almas, N. Andy Cole, Marty B. Rhoades, Jacek A. Koziel Aug 2004

Application Rate And Timing Effects On Urease Inhibitor Performance For Minimizing Ammonia Emissions From Beef Cattle Feedyards, David B. Parker, Syam Pandrangi, L. Wayne Greene, Lal K. Almas, N. Andy Cole, Marty B. Rhoades, Jacek A. Koziel

Jacek A. Koziel

A laboratory study was conducted to evaluate how rate and timing of urease inhibitor application affects ammonia emissions from simulated beef cattle feedyard surfaces. The urease inhibitor N-(n-butyl)thiophosphoric triamide (NBPT) was applied at rates of 0, 1 and 2 kg/ha, at 8, 16, and 32 day frequencies, and with or without simulated rainfall. Synthetic urine was added every 2 days to the manure surface. Gaseous NH3 was trapped in a sulfuric acid solution using a vacuum system and analyzed for nitrogen using automated procedures. NBPT applied every 8 days was most effective, with the 1 and 2 kg/ha NBPT treatments …


Multidimensional Gas Chromatography-Olfactometry For Identification And Prioritization Of Malodors From Confined Animal Feeding Operations, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen, Fred W. Kuhrt, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker Aug 2004

Multidimensional Gas Chromatography-Olfactometry For Identification And Prioritization Of Malodors From Confined Animal Feeding Operations, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen, Fred W. Kuhrt, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker

Jacek A. Koziel

Odor profiling efforts were directed at applying to high-density livestock operations, some of the lessons learned in resolving past, highly diverse, odor-focused investigations in the consumer product industry. Multidimensional-GC-Olfactometry was utilized in an attempt to define and prioritize the basic building blocks of odor character associated with representative cattle feedyard and swine feeding operations. Although scores of potential odorant volatiles have been previously identified in high-density livestock operations, the odor profile results developed herein suggest that only a very few of these may constitute the preponderance of the odor complaints associated with these environments. This appeared to be especially true …


Evaluation Of Sample Recovery Of Malodorous Gases From Air Sampling Bags, Spme, And Sampling Canisters, Jacek A. Koziel, Jarett P. Spinhirne, Jenny D. Lloyd, David B. Parker, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen Aug 2004

Evaluation Of Sample Recovery Of Malodorous Gases From Air Sampling Bags, Spme, And Sampling Canisters, Jacek A. Koziel, Jarett P. Spinhirne, Jenny D. Lloyd, David B. Parker, Donald W. Wright, David K. Eaton, Lawrence T. Nielsen

Jacek A. Koziel

Odorous gases associated with livestock operations are complex mixtures of hundreds if not thousands of compounds. Research is needed to know how best to sample and analyze these compounds. The main objective of this research was to compare recoveries of a standard gas mixture of 11 odorous compounds from the Carboxen/PDMS 75 µ m SPME fibers, PVF (Tedlar), FEP (Teflon), foil, and PET (Melinex) air sampling bags, and standard 6 L Stabilizer™ sampling canisters after sample storage at room temperature. A standard mixture consisted of 7 VFAs from acetic to hexanoic, and 4 semi-VOCs including p-cresol, indole, 4-ethylphenol, and 2'-aminoacetopheone …


Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan Aug 2004

Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan

Michelle L. Soupir

Land applications of manure from confined animal systems and direct deposit by grazing animals are both major sources of nutrients in streams. An understanding of the overland transport mechanisms from land applied waste is needed to improve design of best management practices and modeling of NPS pollution. Release and transport plots were established to study in-field nutrient release and transport from pasturelands receiving phosphorus based livestock waste applications. The release plots determined the concentrations available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, standard cowpies, and none) and three …


Educational Needs For Agri-Industrial Facility Designers And Managers, Gregory D. Williams, Kurt A. Rosentrater, David R. Bohnhoff Aug 2004

Educational Needs For Agri-Industrial Facility Designers And Managers, Gregory D. Williams, Kurt A. Rosentrater, David R. Bohnhoff

Kurt A. Rosentrater

This paper summarizes educational needs for agri-industrial facility designers and mangers. Relevant skills required for the design, planning, and operation of agri-industrial facilities are discussed. Continuing and University educational needs for facility designers and managers are also presented.


Analysis Of Factors Affecting Corn Masa Byproduct Generation, Kurt A. Rosentrater Aug 2004

Analysis Of Factors Affecting Corn Masa Byproduct Generation, Kurt A. Rosentrater

Kurt A. Rosentrater

The production of corn masa-based products in the U.S. has been increasing over the last several years, and consequently, so has the volume of waste materials generated from this processing sector. These byproducts, which consist of corn dry matter losses that occur during the nixtamalization process, are currently underutilized, but have much potential for value-added processing and utilization, and thus hold the simultaneous promises of economic benefit for corn processors as well as decreased potential impact on surrounding ecosystems. Because information concerning masa byproducts, and the rate at which they are generated, is currently very limited and not readily available, …


Comparison Of Vrt Granular Applicators, John P. Fulton, Scott A. Shearer, Steven F. Higgins, Timothy S. Stombaugh, Matthew J. Darr, Dennis W. Hancock, Edward L. Hutchins Aug 2004

Comparison Of Vrt Granular Applicators, John P. Fulton, Scott A. Shearer, Steven F. Higgins, Timothy S. Stombaugh, Matthew J. Darr, Dennis W. Hancock, Edward L. Hutchins

Matthew J. Darr

Granular applicators equipped with variable-rate technology have gained popularity in recent years due to increased interests in variable-rate application. The purpose of this investigation was to characterize distribution patterns at varying rates and quantify rate transitions from various granular applicators. Both uniform- and variable-rate tests were conducted to assess the accuracy of variable-rate application from four granular applicators (2 spinner spreaders and 2 pneumatic applicators). The patterns results indicated a consistent triangular pattern for spinner spreader B and consistent patterns for pneumatic applicators C and D. However, applicator D produced pattern variations at the center and right side. Simulated overlap …


Ambient Ammonia And Hydrogen Sulfide Concentrations At A Beef Cattle Feedlot In Texas, Jacek A. Koziel, Bok-Haeng Baek, Jarett P. Spinhirne, David B. Park Aug 2004

Ambient Ammonia And Hydrogen Sulfide Concentrations At A Beef Cattle Feedlot In Texas, Jacek A. Koziel, Bok-Haeng Baek, Jarett P. Spinhirne, David B. Park

Jacek A. Koziel

Concentrations of ammonia (NH3) and hydrogen sulfide (H2S) in ambient air were semicontinuously measured at a 50,000-head cattle feedyard in Texas panhandle in three seasons: fall 2002 (10 days), winter 2003 (14 days), and spring 2003 (15 days). Sampling was conducted at 1.5 m above the ground at one location each season at the western fence line of cattle pens. Gas concentrations were measured using continuous analyzers housed in an onsite instrument shelter. Measured concentrations were upwind or downwind of the feedyard pens depending on the wind direction. Wind directions, wind velocity, and air temperature were measured to correlate them …


Post-Tier Rail And Typar® Or Metal-Covered Tobacco Field Curing Structures, George A. Duncan Jul 2004

Post-Tier Rail And Typar® Or Metal-Covered Tobacco Field Curing Structures, George A. Duncan

Agricultural Engineering Extension Publications

Tobacco producers are rapidly adopting field curing structures with several variations in construction materials and methods. They are looking to lower costs and increase efficiency by installing structures that require less maintenance and last longer.

Two recently designed structures appear to provide more permanent options for producers who dislike the tedious tasks of covering and securing the plastic over the tobacco during the curing season. Both structures use two-rail-wide, two-post wooden construction, but they differ in their roof coverings. One uses Typar®, and the other uses metal.


Effect Of Moisture Content And Broken Kernels On The Bulk Density And Packing Of Corn, Samuel G. Mcneill, Sidney A. Thompson, Michael D. Montross Jul 2004

Effect Of Moisture Content And Broken Kernels On The Bulk Density And Packing Of Corn, Samuel G. Mcneill, Sidney A. Thompson, Michael D. Montross

Biosystems and Agricultural Engineering Faculty Publications

Shelled yellow dent corn samples were conditioned to three moisture content levels (12%, 15%, and 18% w.b.) and mixed with a prescribed amount of broken corn particles of known size (geometric mean diameter of 1.0, 1.4, 2.0, 2.8, and 4.0 mm) and concentration (2.5%, 5.0%, and 7.5% by weight) levels. The initial bulk density and grain compaction under simulated overburden pressure tests were determined for each sample. Uniaxial compression tests were performed for seven vertical pressure levels (3.4, 6.9, 14, 28, 55, 110, and 165 kPa) with a minimum of three replications each. Tests were performed at two locations with …


Estrogen Content Of Dairy And Swine Wastes, D. Raj Raman, Elizabeth L. Williams, Alice C. Layton, Robert T. Burns, James P. Easter, Adam S. Daugherty, Michael D. Mullen, Gary S. Sayler Jul 2004

Estrogen Content Of Dairy And Swine Wastes, D. Raj Raman, Elizabeth L. Williams, Alice C. Layton, Robert T. Burns, James P. Easter, Adam S. Daugherty, Michael D. Mullen, Gary S. Sayler

D. Raj Raman

Naturally occurring estrogens in animal wastes may cause negative environmental impacts, yet their abundance in animal waste treatment and storage structures is poorly documented. To better quantify estrogen concentra tions in animal wastes, multiple waste samples were collected from treatment and storage structures at dairy and swine facilities and analyzed for concentrations of 17β-estradiol (E2), estrone (E1), and 17α-estradiol by gas chromatography−mass spectroscopy and by enzyme linked immunosorbent assay (E2 only). Mass ratios of each estrogen to the macronutrients nitrogen, phosphorus, and potassium were also determined. Because manure application rates are typically macronutrient-based, estrogen to macronutrient ratios are proportional to …


Suitability Of A Gps Collar For Grazing Studies, Carmen T. Agouridis, Timothy S. Stombaugh, Stephen R. Workman, Benjamin K. Koostra, Dwayne R. Edwards, Eric S. Vanzant Jul 2004

Suitability Of A Gps Collar For Grazing Studies, Carmen T. Agouridis, Timothy S. Stombaugh, Stephen R. Workman, Benjamin K. Koostra, Dwayne R. Edwards, Eric S. Vanzant

Biosystems and Agricultural Engineering Faculty Publications

The traditional means of tracking animal location in a field is by visual observation. Not only is this method labor intensive, it is also prone to error as the observer can alter cattle movement, observation periods are often too short to obtain confidence in general daily behavior patterns, and observer fatigue becomes an issue. In the 1990s, the University of Kentucky began using GPS collars on cattle to track their position with the goal of incorporating this information into cattle management practices. One of the key unanswered questions regarding the GPS collars is the accuracy of the position data recorded …


Genetic Algorithm-Based Model For Determination Of Efficient Management Strategies For Irrigation Canal Networks, Talaat Taher El Gamel Jul 2004

Genetic Algorithm-Based Model For Determination Of Efficient Management Strategies For Irrigation Canal Networks, Talaat Taher El Gamel

Civil & Environmental Engineering Theses & Dissertations

An optimization model for the determination of efficient management strategies for an irrigation canal network is developed. The objective is to minimize the total water consumed while satisfying various system constraints. An unsteady flow model is used to simulate the flow in the network. A genetic algorithm- (GA-) based framework is used to solve the model. The suitable GA parameters that should be used within the model, as well as the performance of various constraint-handling techniques, are studied. Uncertainties in crop pattern and water consumption rates are incorporated into the search procedure to identify more reliable solutions. A graphical interface …


A Nebraska Odor Footprint Tool For Planning Pork Facilities, Richard Koelsch Jul 2004

A Nebraska Odor Footprint Tool For Planning Pork Facilities, Richard Koelsch

Biological Systems Engineering: Papers and Publications

Pork producers and rural communities are struggling to balance air quality issues (primarily odors) with the presence and growth of the industry. Currently the type of pork facility, odor control measures, prevailing wind direction, atmospheric conditions, and a community's tolerance to some degree of odor are largely ignored in the planning process because scientific tools that incorporate this information are lacking. Without such tools, decisions on setback distances and acceptable type and size of facilities are influenced by a range of arguments, often emotional in nature. In addition, pork producers lack tools to assist in evaluating impact on a rural …


Zone Heating For Wean-To-Finish Facilities: A Performance Comparison, Rick R. Stowell May 2004

Zone Heating For Wean-To-Finish Facilities: A Performance Comparison, Rick R. Stowell

Biological Systems Engineering: Papers and Publications

Farm research trials were conducted in 2003 and 2004 to assess the effects of the type of zone heater and floor mat used in a wean-to-finish building on the thermal environment created for newly weaned pigs and resulting pig performance. Modulated LP gas-fired brooder heaters were compared to electric heat lamps, and floor mats made from farm-cut wood sheathing (3/8” oriented-strand board, OSB) were compared to commercial [unheated] rubber mats in a replicated 2x2 factorial experiment. No consistent differences in air temperature near the heating zone were found between either of the treatments, with treatment means within 1oF …


Effect Of Stover Fraction On Glucose Production Using Enzymatic Hydrolysis, Czarena L. Crofcheck, Michael D. Montross May 2004

Effect Of Stover Fraction On Glucose Production Using Enzymatic Hydrolysis, Czarena L. Crofcheck, Michael D. Montross

Biosystems and Agricultural Engineering Faculty Publications

Corn stover was fractionated into three fractions: cobs, stalks, and leaves and husks. The fractions were dried and ground through a 2 mm screen. Samples of the three fractions and whole corn stover with and without NaOH pretreatment were subjected to enzymatic hydrolysis in order to determine the effect of fractionation on glucose production. The average amounts of glucose released after 60 h of hydrolysis from pretreated cobs, leaves and husks, stalks, and whole stover were 0.50, 0.36, 0.28, and 0.36 g/g dry biomass, respectively. The average amounts of glucose released after 60 h of hydrolysis from nonpretreated cobs, leaves …


The Influence Of Environmental Temperature And Substrate Initial Moisture Content On Aspergillus Niger Growth And Phytase Production In Solid−State Cultivation, Seaborn B. Carter, Sue E. Nokes, Czarena L. Crofcheck May 2004

The Influence Of Environmental Temperature And Substrate Initial Moisture Content On Aspergillus Niger Growth And Phytase Production In Solid−State Cultivation, Seaborn B. Carter, Sue E. Nokes, Czarena L. Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Aspergillus niger is being used commercially for phytase production utilizing solid-state cultivation; however, no studies have been published that investigated the optimal environmental temperature and initial substrate water content to maximize fungal growth and/or phytase production. Solid-state cultivations of Aspergillus niger on wheat bran and soybean meal were conducted at three temperatures (25°C, 30°C, and 35°C) and three initial moisture contents (50%, 55%, and 60% wet basis) in a split-plot full-factorial experimental design. Fermentations were conducted for 0, 24, 48, 72, and 120 h. The containers were sampled destructively and assayed for phytase activity and glucosamine concentration as an estimate …


Determining Pesticide Persistence On Plastic Mulches Used As Row Covers In Tennessee, William Tod Pinson May 2004

Determining Pesticide Persistence On Plastic Mulches Used As Row Covers In Tennessee, William Tod Pinson

Masters Theses

During the past decade, the use of plasticulture production systems has become an increasingly common practice for vegetable production in the United States. The plasticulture system is the use of plastic mulch to serve as a row cover in the field. The semi-permeable material can be made of varying densities of polyethylene, and serves as a barrier that helps maintain soil moisture and reduce weed growth. Increased use of these plastics has created a waste management problem, as producers have difficulties trying to find the best and cheapest disposal method. A few companies had begun collecting the materials for reprocessing …


Irrigation District Observations On Large Diameter, Low Pressure Pipeline Materials, Charles M. Burt Mar 2004

Irrigation District Observations On Large Diameter, Low Pressure Pipeline Materials, Charles M. Burt

BioResource and Agricultural Engineering

There are approximately 1,400 miles of low pressure non-reinforced cast-in-place ("monolithic" or "CIP") concrete pipe in California irrigation districts. Cast-in-place pipe was irrigation districts’ material of choice for large diameter pipelines from 1930 to at least 1980. Many of these pipelines were installed in the early 1900’s. They are predominately found on the east side of the San Joaquin Valley, from Manteca in the north to Visalia in the south. Most of these pipes are deteriorating and will need to be replaced within the next 10-20 years.

Irrigation districts have attempted to find new ways to repair these pipes. However, …