Biological Engineering Commons^™

Climate Change Impacts On Streamflow, Water Quality, And Best Management Practices For The Shell And Logan Creek Watersheds In Nebraska, M. W. Van Liew, S. Feng, T. B. Pathak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Improvements in the management of water, sediment, and nutrients under future climatic conditions are needed to ensure increased crop and livestock production to meet greater global needs and the future availability of water for competing demands and protection against adverse water quality impairments. This study determined the impacts of future climate change scenarios on streamflow, water quality, and best management practices (BMPs) for two watersheds in Nebraska, USA. The Soil and Water Assessment Tool (SWAT) was employed to simulate streamflow, sediment, total nitrogen (N) and total phosphorus (P) from the Shell Creek Watershed near Columbus, Nebraska and the Logan Creek …

Carbon, Water, And Heat Flux Responses To Experimental Burning And Drought In A Tallgrass Prairie, Marc L. Fischer, M S. Torn, David P. Billesbach, Geoffrey Doyle, Brian Northup, Sebastien C. Biraud

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Drought and fire are common disturbances to grassland ecosystems. We report two years of eddy covariance ecosystem–atmosphere fluxes and biometric variables measured in nearby burned and unburned pastures in the US Southern Great Plains. Over the course of the experiment, annual precipitation (∼600 mm yr⁻¹) was lower than the long term mean (∼860 mm yr⁻¹). Soil moisture decreased from productive conditions in March 2005 dry, unproductive conditions during the growing season starting in March 2006. Just prior to the burn in early March 2005, burned and unburned pastures contained 520 ± 60 and 360 ± 40 …

Global Estimation Of Evapotranspiration Using A Leaf Area Index-Based Surface Energy And Water Balance Model, H. Yan, S.Q. Wang, David P. Billesbach, Walter Oechel, J.H. Zhang, Tilden Meyers, Ta. Martin, Roser Matamala, Dennis D. Baldocchi, G. Bohrer, D. Dragoni, R. Scott

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Studies of global hydrologic cycles, carbon cycles and climate change are greatly facilitated when global estimates of evapotranspiration (E) are available. We have developed an air-relative-humidity-based two-source (ARTS) E model that simulates the surface energy balance, soil water balance, and environmental constraints on E. It uses remotely sensed leaf area index (L_ai) and surface meteorological data to estimate E by: 1) introducing a simple biophysical model for canopy conductance (G_c), defined as a constant maximum stomatal conductance g_smax of 12.2mm s⁻¹multiplied by air relative humidity (R_{h …}

Energy Issues Affecting Corn/Soybean Systems: Challenges For Sustainable Production, Douglas L. Karlen, David Archer, Adam Liska, Seth Meyer

Adam Liska Papers

Quantifying energy issues associated with agricultural systems, even for a two-crop corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) rotation, is not a simple task. It becomes even more complicated if the goal is to include all aspects of sustainability (i.e., economic, environmental, and social). This Issue Paper examines energy issues associated with and affecting corn/soybean rotations by first defining the size of the system from both a U.S. and global perspective and then establishing boundaries based on the Farm Bill definition of sustainability. This structured approach is essential to help quantify energy issues within corn/soybean …

Subsurface Phosphorus Transport And Scale Dependent Phosphorus Leaching In Alluvial Floodplains, Derek Michael Heeren

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Increased nutrient loads have resulted in several adverse impacts on surface water quality, including excessive algal growth, fish kills, and drinking water taste and odor issues across the United States and especially in the Ozark ecoregion of northeastern Oklahoma and northwestern Arkansas. Nitrogen is a concern, but phosphorus (P) is generally considered the limiting nutrient in most surface water systems. Scientists and engineers need to identify critical nutrient source areas and transport mechanisms within a catchment in order to cost effectively protect and enhance drinking water systems, recreation activities, and aquatic ecosystems. While surface runoff is considered to be the …

Effect Of Extracellular Matrix (Ecm) Protein Micropatterns On The Behavior Of Human Neuroblastoma Cells, Ishwari Poudel

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Recent advances in patterning techniques and emerging surface microtechnologies have allowed cell micropatterning to control spatial location of the cells on a surface as well as cell shape, attachment area, and number of contacting neighbor cells. These parameters play important roles in cell cellular behaviors. Cell micropatterning has thus become one of the most important strategies for biomedical applications, such as, tissue engineering, diagnostic immunoassays, lab-on-chip devices, bio-sensing, etc., and cell biology studies as well. For neuronal cells, there have been attempts to distribute neuronal cells on specific patterns to control cell-to-cell interaction. However, there have been very limited understanding …

Studies On Power Hop Using A Nonlinear Model Of An Agricultural Tractor, Adam B. Flaugh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Power hop is an unstable dynamic phenomenon that is observed on agricultural tractors operating at field working speeds under typical draft loads. This dynamic instability can be identified as a bounce motion preceded by an increasing oscillation in either the pitch or bounce modes. A definite and comprehensive correction or prevention strategy for the control of power hop does not exist. In this work a linear and a nonlinear model of an agricultural tractor were developed. The method of multiple time scales has been employed in the analysis of the nonlinear model. Numerical results have been obtained using Mathematica to …

The Economics And Logistics Of The Dual Harvest Of Grain And Biomass In A Single-Pass, Matthew T. Wold

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Significant interest has developed in using cellulosic resources, especially crop residues, to create biofuels. Collecting these residues in a single-pass of the harvester across the field has the potential to be a low cost option. Two models have been developed; the first characterizes the in-field logistics of single-pass crop residue collection, the second the economics. These models allow the user to easily examine a wide variety of both grain-only and single-pass residue collection harvest cases. A variety of possible residue collection cases have been examined, and their effects both on harvester field capacity and harvest cost compared to grain-only harvest …

A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

It is well known that biological systems utilize communication in some form, one prolific example of this is the propagation of HIV (Human Immunodeficiency Virus) in the human body. By modeling HIV infection as a communication system, we hope to gain a unique insight into HIV and biological communication systems in general. Such a model would provide researchers a platform for experimenting and simulating various biological communication systems. We have previously developed a layered communication protocol for interpreting biological communication systems using telecommunications paradigms and will apply said model to HIV proliferation. We will also demonstrate the effectiveness of the …

Climate Change Policy Could Make Keystone Xl Obsolete, Adam Liska

Adam Liska Papers

Clearly the Keystone XL pipeline threatens both surface and ground water that sustains the agricultural economy of Nebraska, but the projected profitability of tar sands oil and the pipeline operation are dependent on the future economics of climate change. Three recent scientific studies estimate the total carbon intensity of tar sands-based gasoline from Alberta (from both production and burning of the fuel) at an average of roughly 22 percent higher than U.S. gasoline in 2005, with the range of average carbon intensities for tar sands-gasoline at 16 to 27 percent higher than most other sources.

Extrusion And Alkali Extrusion Of Corn Stover To Improve Enzyme Saccharification, Shujing Zhang

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Biomass pretreatment constitutes an important part in the whole process of bioethanol production. The main goals of pretreatment include improving cellulose accessibility to enzyme, enhancing sugar yields from hemicellulose, achieving low capital and energy costs, as well as low sugar degradation and low chemical requirements. Extrusion, as a continuous and high throughput pretreatment method, requires much less chemical compared to traditional alkali pretreatment. In this research, twin-screw extrusion was evaluated for its effect with regard to promoting sugar yields from corn stover. Also, the underlying factors contributing to this improvement were examined. It was found that extrusion with no chemicals …

Quantitative Analysis Of The Reaction Between Gliadin And Citric Acid Under Weak Acidic And Weak Alkaline Conditions, Wei Li

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Gliadin was reacted with citric acid under weak acidic and weak alkaline conditions in both wet and dry states and the reaction mechanism was studied. The low morphological stability in an aqueous environment and inferior mechanical properties have restricted the applications of plant proteins, although these materials possess a unique structure, biocompatibility and biodegradability. Carboxylic acids such as citric acid are inexpensive and nontoxic chemicals and are preferred for crosslinking proteins and cellulose to improve the desired properties of the materials.

In this study, gliadin was chosen as a model of plant proteins to react with citric acid. However, previous …

Zein Nanospheres For Gene Delivery, Mary C. Regier

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Particulates incorporating DNA provide for protection and sustained release of DNA, and thus are promising candidates for DNA delivery systems. Among the routes of administration for gene delivery, the oral route is perhaps the most appealing as it is associated with patient comfort and compliance and allows for targeting to intestinal targets for therapeutic and vaccination applications. With the goal of realizing the potential of an oral DNA delivery system, zein, a hydrophobic protein from corn that is biocompatible and degraded enzymatically, was investigated. This thesis describes the formulation of zein nanospheres encapsulating DNA by a coacervation technique and their …

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …

Monitoring Of Mesenchymal Based Constructs Using Magnetic Resonance Elastography, Evan T. Curtis

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Evaluating the functionality of an engineered material lies in the proper characterization of its material and functional properties. In the treatment of musculoskeletal disorders, engineered bone or fat tissue must behave as an adequate replacement else failure of the material could result in discomfort and further surgical procedures. A significant material characteristic that reflects tissue development is the mechanical properties (i.e. shear strength and viscosity). Shear strength and viscosity provide an indication of how efficient the material is in dissipating energy. Energy dissipation occurs naturally in many tissues including fat and can prevent damage to deeper tissues. Many of the …

Review Of Gasoline, Diesel, And Ethanol Biofuels From Grasses And Plants, By Ram B. Gupta And Ayhan Demirbas., Adam J. Liska

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A new book on the production of biofuels by Gupta and Demirbas provides technical insight into the conversion processes that could provide a range of domestic fuels from plant materials to substitute for foreign oil. It focuses primarily on conversion processes for production of cellulosic ethanol, Fischer-Tropsch diesel, pyrolysis bio-oil, and hydrothermal biocrude from biomass resources, as well as "first-generation" grain ethanol and biodiesel from vegetable oil. In addition to a detailed summary of these chemical processes, the book provides a briefer treatment of related matters such as biofuel policy, economics, and environmental issues.

Analysis Of Site-Specific Adjustment Applied To On-The-Go Soil Sensing Data For Agronomic Use, Allison K. Jonjak

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Successful variable-rate applications of agricultural inputs such as lime rely on the quality of input data. Systematic grid soil sampling is the most common method used for creating variable rate prescription maps. The insufficient number of point measurements usually obtained using this method has been primarily responsible for the typical inaccuracies seen in lime prescription maps. To increase sampling density, on-the-go sensing technology was developed for the mapping of soil pH and other relevant attributes. In this study, five fields in eastern Nebraska were mapped using both on-thego sensing technology and systematic grid sampling. Ten calibration points per field were …

Nutrient Runoff Following Manure Application, Chance Thayer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

A field study was completed to measure the effects of varying flow rate on nutrient transport following the application of varying amounts of beef cattle manure to plots containing either no-residue or a wheat residue cover.  Beef cattle manure was applied and incorporated into the soil in May 2010 to meet zero, one, two, four or eight year corn phosphorus requirements. Simulated rainfall events were applied in June and July 2010. The presence of a crop residue cover significantly increased the transport of dissolved phosphorus, total phosphorus, NO₃-N, NH₄-N, and total nitrogen in runoff but decreased …

Characterization Of Potential Health Promoting Lipids In The Co-Products Of De-Flossed Milkweed, Vicki Schlegel, Richard Zbasnik, Tammy Gries, Bo Hyun Lee, Timothy Carr, Ji-Young Lee, Curtis Weller, Susan Cuppett

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The floss and oil of the common milkweed (Asclepias syriaca L.) seeds are currently used to produce comforters/pillows and skin care products, respectively. As an outcome of these products, copious quantities co-products (pressed seed meal and pod biomass) are disposed of each year despite the presence of potential health benefiting lipids. The objective of this project was to determine the feasibility of developing the lipid fraction from of these co-products for the fast growing dietary human health market. Although certain types of lipids were affected by the extraction solvent used (hexane and diethyl ether) as were overall amounts, analysis …

Life Cycle Assessment Of Greenhouse Gas Emissions From Ethanol And Biopolymers, Adam J. Liska, Xiao Xue Fang

Adam Liska Papers

Conclusions

• Regulatory LCA is not likely to be used for non‐fuel chemicals alone in the near future

• Significant GHG emission credits for corn‐ethanol can be obtained by using only roughly 6‐9% of initial starch for production of biopolymers based on previous LCA theory

• Pay close attention to values in calculating credits per kg—these have to stand up in litigation to ensure the credit

• Credits are proportional to the mass of polymer produced

• Many theoretical issues are uncertain and credits will only be determined in conjunction with EPA

• Indirect emissions are uncertain and are a …

Department Of Biological Systems Engineering Newsletter, Volume 7, Number 1, March 2011

BSE Department Magazine

No abstract provided.

Ethanol Yields And Cell Wall Properties In Divergently Bred Switchgrass Genotypes, Gautam Sarath, Bruce S. Dien, Aaron J. Saathoff, Kenneth P. Vogel, Robert B. Mitchell, Han Chen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Genetic modification of herbaceous plant cell walls to increase biofuels yields is a primary bioenergy research goal. Using two switchgrass populations developed by divergent breeding for ruminant digestibility, the contributions of several wall-related factors to ethanol yields was evaluated. Field grown low lignin plants significantly out yielded high lignin plants for conversion to ethanol by 39.1% and extraction of xylans by 12%. However, across all plants analyzed, greater than 50% of the variation in ethanol yields was attributable to changes in tissue and cell wall architecture, and responses of stem biomass to diluteacid pretreatment. Although lignin levels were lower in …

Evaluation Of A Stream‐Aquifer Analysis Test For Deriving Reach‐Scale Streambed Conductance, Garey A. Fox, Derek M. Heeren, Michael A. Kizer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Extracting groundwater from pumping wells located adjacent to streams can reduce streamflow, a result that is known as alluvial well depletion. Numerous analytical solutions have been developed for alluvial well depletion that vary in their mathematical complexity. Predicted drawdown by the analytical solutions can be matched to observed drawdown from a stream–aquifer analysis (SAA) test (i.e., a pumping test adjacent to a stream) to simultaneously estimate aquifer and streambed hydrologic parameters. However, only a few SAA tests have been documented in the literature and compared to field–measured streambed parameters. Therefore, the objective of this research was to perform an SAA …

Biocomposites Developed Using Water-Plasticized Wheat Gluten As Matrix And Jute Fibers As Reinforcement, Narendra Reddy, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biocomposites developed from wheat gluten using water without any chemicals as plasticizer and jute fibers as reinforcement have much better flexural and tensile properties than similar polypropylene composites reinforced with jute fibers. Wheat gluten is an inexpensive and abundant co-product derived from renewable resources and is biodegradable but non-thermoplastic. Previous attempts at developing biocomposites from wheat gluten have used plasticizers such as glycerol or chemical modifications to make gluten thermoplastic. However, plasticizers have a considerably negative effect on the mechanical properties of the composites and chemical modifications make wheat gluten less biodegradable, expensive and/or environmentally unfriendly. In the research reported, …

Corn Seed Spacing Uniformity As Affected By Seed Tube Condition, Michael F. Kocher, John M. Coleman, John A. Smith, Stephen D. Kachman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Variation in corn seed spacing from a John Deere MaxEmerge^TM Plus Vacumeter planter was evaluated on the University of Nebraska Planter Test Stand in a laboratory setting for two seed tube conditions (new or worn) with two examples of corn seed shape (round or flat). Seed spacing uniformity was measured using three seed spacing uniformity parameters: Coefficient of Precision (CP3), ISO Multiples index, and ISO Miss index.

Differences were detected in all three seed spacing uniformity parameters due to the seed tube condition. The new seed tubes had better seed spacing uniformity than the worn seed tubes, within each …

Spatial Variability Of Field Machinery Use And Efficiency, Viacheslav I. Adamchuk, Robert Grisso, Michael F. Kocher

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In site-specific crop management, It is a common practice to log the geographic coordinates of agricultural machinery measured using a global satellite navigation system (GNSS) such as the global positioning system (GPS). Yield, fertilizer application, and seed placement maps provide useful data for making agronomic decisions. However, the travel path itself reveals valuable information about machinery performance. Often, during field operations, odd field shapes, obstacles, or contour farming will require operators to increase the complexity of the machinery maneuvering. This usually reduces field efficiency. This chapter presents a methodology to parameterize the spatially variable characteristics of traffic patterns, and to …

Completely Biodegradable Soyprotein–Jute Biocomposites Developed Using Water Without Any Chemicals As Plasticizer, Narendra Reddy, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soyprotein–jute fiber composites developed using water without any chemicals as the plasticizer show much better flexural and tensile properties than polypropylene–jute composites. Co-products of soybean processing such as soy oil, soyprotein concentrate and soy protein isolates are inexpensive, abundantly available and are renewable resources that have been extensively studied as potential matrix materials to develop biodegradable composites. However, previous attempts on developing soy-based composites have either chemically modified the co-products or used plasticizers such as glycerol. Chemical modifications make the composites expensive and less environmentally friendly and plasticizers decrease the properties of the composites. In this research, soyprotein composites reinforced …

Verifying Power Claims Of High‐Power Agricultural Tractors Without A Pto To Sell In Nebraska, Michael F. Kocher, Viacheslav Adamchuk, John A. Smith, Roger M. Hoy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nebraska law requires the Nebraska Tractor Test Board of Engineers to compare results of the tests of an agricultural tractor model with the manufacturer's claims regarding power, fuel use, and other performance ratings in order to recommend a permit to sell that tractor model in the state. PTO tests are conducted to verify the manufacturer's PTO power and fuel claims for tractor models. In recent years, several tractor manufacturers have been producing models of large tractors either without a PTO or with a PTO not capable of transmitting the full engine power and, therefore, have chosen to advertise engine power. …

Evaluation Of Soil Salinity Leaching Requirement Guidelines, John Letey, Glenn J. Hoffman, Jan W. Hopmans, Stephen R. Grattan, Donald Louis Suarez, Dennis L. Corwin, Jim D. Oster, Laosheng Wu, Christopher Amrhein

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water for irrigation is a major limitation to agricultural production in many parts of the world. Use of waters with elevated levels of salinity is one likely option to meet the supply of increased demands. The sources of these waters include drainage water generated by irrigated agriculture, municipal wastewater, and poor quality groundwater. Soil salinity leaching requirements that were established several decades ago were based on steady-state conditions. Recently transient-state models have been developed that potentially can more correctly predict the dynamics of the chemical–physical–biological interactions in an agricultural system. The University of California Center for Water Resources appointed a …

Comparison Of Subsurface And Surface Runoff Phosphorus Transport Rates In Alluvial Floodplains, Aaron R. Mittelstet, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Michael J. White, Ronald B. Miller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Phosphorus (P) loading to streams can occur by both surface runoff and subsurface transport, with subsurface P transport often assumed negligible. Groundwater P concentrations in alluvial aquifers can be significant, especially in preferential flow paths (PFPs). The objectives of this research were to quantify subsurface P transport rates at two sites in northeastern Oklahoma and to compare them with surface runoff P transport rates derived from a hydrologic model, the Pasture Phosphorus Management Calculator (PPM Plus). Ozark ecoregion study sites were adjacent to the Barren Fork Creek and Honey Creek in northeastern OK, USA. Each site, instrumented with 24 observation …