Biological Engineering Commons^™

Modeling Changes In Biomass Composition During Microwave-Based Alkali Pretreatment Of Switchgrass, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study used two different approaches to model changes in biomass composition during microwave-based pretreatment of switchgrass: kinetic modeling using a time-dependent rate coefficient, and a Mamdani-type fuzzy inference system. In both modeling approaches, the dielectric loss tangent of the alkali reagent and pretreatment time were used as predictors for changes in amounts of lignin, cellulose, and xylan during the pretreatment. Training and testing data sets for development and validation of the models were obtained from pretreatment experiments conducted using 1–3% w/v NaOH (sodium hydroxide) and pretreatment times ranging from 5 to 20 minutes. The kinetic modeling approach for lignin …

Ultrasound-Assisted Osmotic Dehydration Of Strawberries: Effect Of Pretreatment Time And Ultrasonic Frequency, Juan Garcia-Noguera, Francisca I. P. Oliveira, Maria Izabel Gallão, Curtis L. Weller, Sueli Rodrigues, Fabiano A. N. Fernandes

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Pretreatment of fruits prior to drying has shown success in reducing drying time and costs. In this work, ultrasound-assisted osmotic dehydration has been implemented as a method to increase water diffusivity and reduce drying time in strawberries. Strawberry halves were immersed in distilled water and in two different concentrations of sucrose solutions while pretreatment time and ultrasonic frequency levels were varied to determine their effect on drying time, water loss, and soluble solids gain. A microscopic analysis was carried out to evaluate the formation of microchannels and other changes to the fruit tissue structure. Greater sucrose concentration used in ultrasound- …

Cytocompatible Cross-Linking Of Electrospun Zein Fibers For The Development Of Water-Stable Tissue Engineering Scaffolds, Quiran Jiang, Narendra Reddy, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This paper reports a new method of cross-linking electrospun zein fibers using citric acid as a non-toxic cross-linker to enhance the water stability and cytocompatibility of zein fibers for tissue engineering and other medical applications. The electrospun structure has many advantages over other types of structures and protein-based biomaterials possess unique properties preferred for tissue engineering and other medical applications. However, ultrafine fiber matrices developed from proteins have poor mechanical properties and morphological stability in the aqueous environments required for medical applications. Efforts have been made to improve the water stability of electrospun protein scaffolds using cross-linking and other approaches, …

Microwave-Based Alkali Pretreatment Of Switchgrass And Coastal Bermudagrass For Bioethanol Production, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Switchgrass and coastal bermudagrass are promising lignocellulosic feedstocks for bioethanol production. However, pretreatment of lignocelluloses is required to improve production of fermentable sugars from enzymatic hydrolysis. Microwave-based alkali pretreatment of switchgrass and coastal bermudagrass was investigated in this study. Pretreatments were carried out by immersing the biomass in dilute alkali reagents and exposing the slurry to microwave radiation at 250 W for residence times ranging from 5 to 20 minutes. Simons’ stain method was used to quantify changes in biomass porosity as a result of the pretreatment. Pretreatments were evaluated based on yields of total reducing sugars, glucose, and xylose. …

Preferential Flow Effects On Subsurface Contaminant Transport In Alluvial Floodplains, Derek M. Heeren, Ron B. Miller, Garey A. Fox, Daniel E. Storm, Todd Halihan, Chad J. Penn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

For sorbing contaminants, transport from upland areas to surface water systems is typically considered to be due to surface runoff, with negligible input from subsurface transport assumed. However, certain conditions can lead to an environment where subsurface transport to streams may be significant. The Ozark region, including parts of Oklahoma, Arkansas, and Missouri, is one such environment, characterized by cherty, gravelly soils and gravel bed streams. Previous research identified a preferential flow path (PFP) at an Ozark floodplain along the Barren Fork Creek in northeastern Oklahoma and demonstrated that even a sorbing contaminant, i.e., phosphorus, can be transported in significant …

Net Radiation Dynamics: Performance Of 20 Daily Net Radiation Models As Related To Model Structure And Intricacy In Two Climates, Suat Irmak, Denis Mutiibwa, José O. Payero

Department of Agricultural and Biological Systems Engineering: Faculty Publications

We compared daily net radiation (R_n) estimates from 19 methods with the ASCE‐EWRI R_n estimates in two climates: Clay Center, Nebraska (sub‐humid) and Davis, California (semi‐arid) for the calendar year. The performances of all 20 methods, including the ASCE‐EWRI R_n method, were then evaluated against R_n data measured over a non‐stressed maize canopy during two growing seasons in 2005 and 2006 at Clay Center. Methods differ in terms of inputs, structure, and equation intricacy. Most methods differ in estimating the cloudiness factor, emissivity (α), and calculating net longwave radiation (R_nl). All methods use …

Development Of The Mask Scentometer, A Comparison Of Ambient Odor Assessment Methods, And Their Application In Ground Truthing Atmospheric Dispersion Models, Christopher G. Henry

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

This dissertation is organized as four stand-alone papers. Paper No. 1 describes the development of the Mask Scentometer and reports dilution ratios measured during use by twelve different people. Dilution ratios at the Mask Scentometer’s five dilution-to-threshold (D/T) settings were found to be 0.35, 1, 2, 4.5 and 18. In Paper No.’s 2 and 4, ambient odor assessment methods were compared in both controlled laboratory conditions and in the field. Laboratory analysis of ambient air samples using dynamic triangular forced-choice olfactometry (DTFCO) did not correlate well with any of the ambient odor assessment methods. Average intensity-predicted D/T was roughly five …

Responses To “Comment On ‘Response To Plevin: Implications For Life Cycle Emissions Regulations’” And “Assessing Corn Ethanol: Relevance And Responsibility”, Adam Liska, Kenneth Cassman

Adam Liska Papers

This letter responds to two issues concerning the greenhouse gas (GHG) emissions intensity of corn-ethanol that were raised in discussions of our response (Liska and Cassman 2009) to Plevin’s article (2009), which critiques our original research (Liska et al. 2009) published in the Journal of Industrial Ecology. ... The suggestion by Anex and Lifset (2009) that corn-ethanol does not reduce GHG emissions by 47% compared to gasoline, but instead by “somewhere between” 35 to 40%, is unsubstantiated.

Extraction And Characterization Of Natural Cellulose Fibers From Common Milkweed Stems, Narendra Reddy, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Natural cellulose fibers with cellulose content, strength, and elongation higher than that of milkweed floss and between that of cotton and linen have been obtained from the stems of common milkweed plants. Although milkweed floss is a unique natural cellulose fiber with low density, the short length and low elongation make milkweed floss unsuitable as a textile fiber. The possibility of using the stems of milkweed plant as a source for natural cellulose fibers was explored in this research. Natural cellulose fibers extracted from milkweed stems have been characterized for their composition, structure, and properties. Fibers obtained from milkweed stems …

Department Of Biological Systems Engineering Newsletter, Volume 5, Number 1, July 2009

BSE Department Magazine

No abstract provided.

Actual And Reference Evaporative Losses And Surface Coefficients Of A Maize Field During Nongrowing (Dormant) Periods, Christopher H. Hay, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Effective water resources planning, allocation, management, and use in agroecosystems require accurate quantification of actual evapotranspiration (ET_c) during growing and nongrowing (dormant) periods. Prediction of ET_c for a variety of vegetation surfaces during the growing season has been researched extensively, but relatively little information exists on evaporative losses during nongrowing periods for different surfaces. The objectives of this research were to evaluate ET_c in relation to available energy, precipitation, and grass and alfalfa-reference ET (ET_o and ET_r) for a maize (Zea mays L.) field and to analyze the dynamics of surface coefficients …

Synthesis And Characterization Of Hazelnut Oil-Based Biodiesel, Yixiang Xu, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The demand for diesel fuel far exceeds the current and future biodiesel production capabilities of the vegetable oil and animal fat industries. New oilseed crops that do not compete with traditional food crop are needed to meet existing energy demands. Hybrid hazelnut oil is just such an attractive raw material for production of biodiesel. Hazelnut oil was extracted from hybrid hazelnuts and the crude oil was refined. Hazelnut oil-based biodiesel was prepared via the transesterification of the refined hazelnut oil with excess methanol using an alkaline catalyst. The effects of reaction temperature, time and catalyst concentration on the yield of …

Magnitude And Variability In Emissions Savings In The Corn-Ethanol Life Cycle From Feeding Co-Products To Livestock, Virgil R. Bremer, Adam Liska, Terry J. Klopfenstein, Galen E. Erickson, Haishun Yang, Daniel T. Walters, Kenneth G. Cassman

Adam Liska Papers

Conclusions

• Co-product GHG emissions credit varied by >2-fold, from 11.5 to 28.3 gCO₂e per MJ of ethanol produced

• Co-product GHG emissions credit depend on
-types of co-products produced
-proportion fed to beef cattle vs. diary or swine
-location of corn production; the CP credit is highest in regions where GHG kg^-1grain are highest

• Depending on CP production types and feeding livestock classes, corn-ethanol net life cycle GHG intensity is 44-56 gCO₂e per MJ

• Midwest corn-ethanol reduces GHG emissions compared to gasoline by 47% on average, with co-products offsetting 23% of …

Development Of Novel Microwave Cooking Model For Not-Ready-To Eat Foods, Sohan Birla, Krishnamoorthy Pitchai, Jeyamkondan Subbiah, David D. Jones

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Recently safety of microwave cooked food has come under scrutiny because of recent outbreak and recalls associated with some of these not-ready-to-eat (NRTE) frozen foods. Heating uniformity of these foods is paramount in rendering the foods safe for consumption. Degree of uneven microwave heating is influenced by both microwave oven and characteristics of food load which decides the electric field distribution within the food load. Given the complexity of parameters, a computer model is always desirable to optimize heating uniformity by proper selection of food shape, proportions, plating, packaging selection and more. Earlier many researchers have made one or more …

Process Simulation Of Dilute Acid Pretreatment Of Coastal Bermudagrass For Bioethanol Production, Arthur Redding, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Coastal bermudagrass is a promising lignocellulosic feedstock for bioethanol production. It is well suited for the Southeastern United States where it is currently grown for hay production and nutrient management in animal farming operations. Prior experiments have generated sugar and sugar degradation data from the dilute acid pretreatment and enzymatic hydrolysis of bermudagrass over a range of pretreatment conditions. Experimentally, the yield of total glucose and xylose was maximized at 93 % of the theoretical value for the pretreatment conditions 140 °C and 1.2 % sulfuric acid (w/w) for a residence time of 30 minutes. To explore further potential optimum …

Farm Tractor Rollover Protection: Why Simply Getting Rollover Protective Structures Installed On All Tractors Is Not Sufficient, Roger M. Hoy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In North America, agricultural is one of the most hazardous occupations, trailing only mining and construction in likelihood of experiencing a serious injury or fatality. Without quoting specific statistics, roughly one-half of the serious injuries experienced each year involve an agricultural tractor, and roughly one-half of the serious injuries involving tractors are rollovers. It is well established that when a tractor is equipped with a rollover protective structure (ROPS) and seatbelt, and both are utilized, serious injuries rarely, if ever occur, in the event of an overturn. In fact, tractor overturns are the leading cause of agricultural fatalities in the …

Switchgrass For Bioethanol And Other Value-Added Applications: A Review, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Switchgrass is a promising feedstock for value-added applications due to its high productivity, potentially low requirements for agricultural inputs and positive environmental impacts. The objective of this paper is to review published research on the conversion of switchgrass into bioethanol and other value-added products. Environmental benefits associated with switchgrass include the potential for carbon sequestration, nutrient recovery from runoff, soil remediation and provision of habitats for grassland birds. Pretreatment of switchgrass is required to improve the yields of fermentable sugars. Based on the type of pretreatment, glucose yields range from 70% to 90%, and xylose yields range from 70% to …

Plant Sterol And Policosanol Characterization Of Hexane Extracts From Grain Sorghum, Corn, And Their Ddgs, Caolina Leguizamón, Curtis L. Weller, Vicki L. Schlegel, Timothy P. Carr

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Plant sterols (PS) and policosanols (PC) have been attributed with plasma cholesterol-lowering properties in humans. Hexane extracts from grain sorghum, corn and their distillers dried grain with solubles (DDGS), an important co-product of ethanol production, contain these health promoting compounds, which could be used to develop health promoting dietary products. However, limited information is currently available regarding optimal methods of extraction and their influence on plant sterol or PC levels and compositions. Therefore, the objective of this study was to quantify lipids, particularly PS and PC extracted from grain sorghum and its DDGS using reflux and Soxtec methods. Corn and …

Thermal Degradation Kinetics Of Distillers Grains And Solubles In Nitrogen And Air, Lijun Wang, Ajay Kumar, Milford Hanna, Curtis L. Weller, D. D. Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The pyrolysis and oxidation kinetics of distillers grains and solubles were determined using thermogravimetric analysis. The starting temperature of pyrolysis and oxidation of distillers grains and solubles increased with the increase of heating rate and initial moisture content. The pyrolysis and oxidation of distillers grains and solubles were completed at 650°C and 850°C, respectively, which were independent of the heating rate and the initial moisture content. The residual weights of distillers grains and solubles after pyrolysis and oxidation were 27.15% and 5.49% of the original dry mass of distillers grains and solubles. Thermogravimetrical analysis data was used to determine kinetic …

Indirect Land Use Emissions In The Life Cycle Of Biofuels: Regulations Vs. Science, Adam J. Liska, Richard K. Perrin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Recent legislative mandates have been enacted at state and federal levels with the purpose of reducing life cycle greenhouse gas (GHG) emissions from transportation fuels. This legislation encourages the substitution of fossil fuels with “low-carbon” fuels. The burden is put on regulatory agencies to determine the GHG-intensity of various fuels, and those agencies naturally look to science for guidance. Even though much progress has been made in determining the direct life cycle emissions from the production of biofuels, the science underpinning the estimation of potentially significant emissions from indirect land use change (ILUC) is in its infancy. As legislation requires …

Sorghum Distillers Dried Grain Lipid Extract Increases Cholesterol Excretion And Decreases Plasma And Liver Cholesterol Concentration In Hamsters, Jia Tse Hoi, Curtis L. Weller, Vicki Schlegel, Susan L. Cuppett, Ji-Young Lee, Timothy P. Carr

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Grain sorghum is a rich source of phytochemicals. In this study, male hamsters were fed AIN-93M diets supplemented with a hexane-extractable lipid fraction from sorghum distillers dried grains with solubles (DDGS). Diets contained 0.0%, 0.5%, 1.0%, and 5.0% (w/w) DDGS lipid extract. After 4 wk, the 5.0% DDGS lipids group had significantly lower plasma non-HDL cholesterol and liver esterified cholesterol concentration. Fecal neutral sterol (i.e., cholesterol) excretion was significantly higher in the 5.0% DDGS lipids group compared to the other treatments (66% higher compared to controls). Bile acid excretion was not affected by DDGS lipid intake. Fecal cholesterol excretion was …

Antiproliferation Properties Of Grain Sorghum Dry Distiller’S Grain Lipids In Caco-2 Cells, Richard Zbasnik, Timothy P. Carr, Curtis L. Weller, Keum Taek Hwang, Lijun Wang, Susan L. Cuppett, Vicki Schlegel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Antiproliferative properties of lipids extracted from grain sorghum (GS) dry distiller’s grain (DDG) were analyzed to determine the feasibility of developing GS coproducts as a source for human health dietary ingredients. The lipid extract of GSDDG was delivered to human colon carcinoma (Caco-2) cells by solubilizing 0−1000 μg/mL of GS-DDG lipids in 100 μg/mL increments with micelles. A significant reduction in cell viability (25−50%) resulted at treatment levels of 400−1000 μg/mL GS-DDG lipids (p < 0.05). Alternatively, total protein levels of cells treated with 400, 500, and 600 μg/mL of GS-DDG lipid were not significantly different from the control, indicating cell growth during the treatment period. Total cell counts for the control were not significantly different from the GS-DDG lipid treated cells, but dead cell counts increased by 10% for the latter sample with a concomitant increase of the intercellular protein lactate dehydrogenase leakage (30−40%) in the medium. Preliminary analysis by the fluorescence-activated cell method (FACs) demonstrated that nonviable cells were in either the early apoptotic, late apoptotic, or necrotic stage post-treatment with 400, 500, and 600 μg/mL GS-DDG lipids. Physiochemical characterization of the GS-DDG lipids used for the antiproliferation study showed the presence of vitamin E (predominantly γ-tocopherol), triacylglycerides (predominantly linoleic acid), policosanols, aldehydes, and sterols (predominantly campesterol and stigmasterol), each of which or as synergistic/additive group of constituents may be responsible for the antiproliferative effect.

Bess: BIofuel ENergy SYstems SImulator: Life Cycle Energy & Emissions Analysis Model For Corn-Ethanol Biofuel Production Systems -- User’S Guide For The Bess Model, Adam Liska, Haishun Yang, Daniel T. Walters, Kenneth Cassman, Terry Klopfenstein, Galen Erickson, Virgil R. Bremer, Richard K. Koelsch, Dan Kenney, Patrick Tracy

Adam Liska Papers

The BESS model is a software tool to calculate the energy efficiency, greenhouse gas (GHG) emissions, and natural resource requirements of corn–to-ethanol biofuel production systems. The model provides a “cradle-to-grave” analysis of the production life cycle of biofuels from the creation of material inputs to finished products, producing an inventory of distributed GHG emissions from fossil fuels and a few key indirect emissions in the production life cycle. The model parameters can be set by the user to achieve the highest accuracy in evaluating a single corn-ethanol biorefinery and its surrounding feedstock crop production zone. The model equations and summary …

Mathematical Modeling Of Growth Of Salmonella In Raw Ground Beef Under Isothermal Conditions From 10 To 45° C, Vijay K. Juneja, Martin Valenzuela Melendres, Lihan Huang, Jeyamkondan Subbiah, Harshavardhan Thippareddi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The objective of this study was to develop primary and secondary models to describe the growth of Salmonella in raw ground beef. Primary and secondary models can be integrated into a dynamic model that can predict the microbial growth under varying environmental conditions. Growth data of Salmonella at nine different isothermal conditions — 10,15, 20, 25, 28, 32, 35, 42, and 45 °C were first fitted into primary models, namely the logistic, modified Gompertz, Baranyi, and Huang models. Performances of these models were evaluated by using various statistical criteria, namely mean square error (MSE), pseudo-R², −2 log likelihood, …

Effect Of Timing Of A Deficit-Irrigation Allocation On Corn Evapotranspiration, Yield, Water Use Efficiency And Dry Mass, J. O. Payero, David D. Tarkalson, Suat Irmak, Don Davison, James L. Petersen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water regulations have decreased irrigation water supplies in Nebraska and some other areas of the USA Great Plains. When available water is not enough to meet crop water requirements during the entire growing cycle, it becomes critical to know the proper irrigation timing that would maximize yields and profits. This study evaluated the effect of timing of a deficit-irrigation allocation (150 mm) on crop evapotranspiration (ETc), yield, water use efficiency (WUE = yield/ETc), irrigation water use efficiency (IWUE = yield/irrigation), and dry mass (DM) of corn (Zea mays L.) irrigated with subsurface drip irrigation in the semiarid climate of …

A Modified Surface Energy Balance For Modeling Evapotranspiration And Canopy Resistance, Luis O. Lagos

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

A modified surface energy balance (SEB) model based on the Shuttleworth-Wallace and Choudhury-Monteith methods was developed to estimate evaporation from soil covered by crop residue, and transpiration from crop canopies. The model describes the energy balance and flux resistances for partially-vegetated and residue-covered surfaces. Physical and biochemical energy storage terms and lateral fluxes are neglected in the model. Net radiation is one of the inputs in the SEB model and provides the energy needed for soil evaporation, crop transpiration and heat transfer through the canopy, soil/residue surfaces and the atmosphere.

A sensitivity analysis of the SEB model parameters showed that …

Department Of Biological Systems Engineering Newsletter, Volume 4, Number 2, December 2008

BSE Department Magazine

Environmental Management Research
From the Department Head
Meet the Faculty
Alumni News
Comings and Goings
Alumna Profile
In Memoriam
Museum Hand-picked for HELP
Urban Water Quality
Summer Graduates
Distinguished Fellowship Awards
Partners in Pollution Prevention Interns
Quarter-scale Tractor Competition
Scholarships and Ice Cream
BSE faculty develop Odor Footprint Tool By Crystal Powers
Ethanol Co-product Storage and Utilization Conference, by John Hay
Biological Systems Engineering Department Hall of Fame: Don Eret and Ned Meier
International Symposium
Faculty and Staff News
University Service Awards
ASABE Annual Meeting

Monitoring Tissue Engineering Using Magnetic Resonance Imaging, Huihui Xu, Shadi F. Othman, Richard L. Magin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Assessment of tissue regeneration is essential to optimize the stages of tissue engineering (cell proliferation, tissue development and implantation). Optical and X-ray imaging have been used in tissue engineering to provide useful information, but each has limitations: for example, poor depth penetration and radiation damage. Magnetic resonance imaging (MRI) largely overcomes these restrictions, exhibits high resolution (approximately 100 μm) and can be applied both in vitro and in vivo. Recently, MRI has been used in tissue engineering to generate spatial maps of tissue relaxation times (T₁, T₂), water diffusion coefficients, and the stiffness (shear moduli) of …

Extracellular Matrix Protein Orientation By Adsorption On Self-Assembled Monolayers Controls Nonviral Gene Delivery, Beth A. Duensing, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

To date, most efforts to understand and improve the efficiency of nonviral gene delivery have focused on altering the physicochemical properties of delivery systems and developing new delivery strategies. The importance of the cellular microenvironment in achieving successful nonviral gene transfer has not been thoroughly examined, though proteins of the extracellular matrix (ECM) mediate cell adhesion and serve to regulate cellular behavior that may, in turn, dictate the cellular responsiveness to nonviral gene delivery. Self-assembled monolayers (SAMs) of alkanethiols on gold were used to control adsorption of ECM molecules and thus control the architecture of the extracellular environment presented to …

Department Of Biological Systems Engineering Newsletter, Volume 4, Number 1, August 2008

BSE Department Magazine

Contents:
New Biomedical Lab Makes Debut
From the Department Head
The Dean's List
Meet the Faculty
Alumni News
Student News
UCARE
Graduates
John Miller: A Success Story
Discover Your Career: Mechanized Systems Management
Alumnus Profile
Faculty and Staff News
Comings and Goings
Spreading the word about No-till