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Articles 991 - 1020 of 1434

Full-Text Articles in Environmental Engineering

Use Of Precisely Sculptured Thin Film (Stf) Substrates With Generalized Ellipsometry To Determine Spatial Distribution Of Adsorbed Fibronectin To Nanostructured Columnar Topographies And Effect On Cell Adhesion, Tadas Kasputis, Alex Pieper, Keith Brian Rodenhausen, Daniel Schmidt, Derek Sekora, Charles Rice, Eva Schubert, Mathias Schubert, Angela K. Pannier May 2015

Use Of Precisely Sculptured Thin Film (Stf) Substrates With Generalized Ellipsometry To Determine Spatial Distribution Of Adsorbed Fibronectin To Nanostructured Columnar Topographies And Effect On Cell Adhesion, Tadas Kasputis, Alex Pieper, Keith Brian Rodenhausen, Daniel Schmidt, Derek Sekora, Charles Rice, Eva Schubert, Mathias Schubert, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sculptured thin film (STF) substrates consist of nanocolumns with precise orientation, intercolumnar spacing, and optical anisotropy, which can be used as model biomaterial substrates to study the effect of homogenous nanotopographies on the three-dimensional distribution of adsorbed proteins. Generalized ellipsometry was used to discriminate between the distributions of adsorbed FN either on top of or within the intercolumnar void spaces of STFs, afforded by the optical properties of these precisely crafted substrates. Generalized ellipsometry indicated that STFs with vertical nanocolumns enhanced total FN adsorption two-fold relative to flat control substrates and the FN adsorption studies demonstrate different STF characteristics influence …


Temporal Endogenous Gene Expression Profiles In Response To Polymer-Mediated Transfection And Profile Comparison To Lipid-Mediated Transfection, Timothy M. Martin, Sarah A. Plautz, Angela K. Pannier Jan 2015

Temporal Endogenous Gene Expression Profiles In Response To Polymer-Mediated Transfection And Profile Comparison To Lipid-Mediated Transfection, Timothy M. Martin, Sarah A. Plautz, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background Design of efficient nonviral gene delivery systems is limited by the rudimentary understanding of specific molecules that facilitate transfection.

Methods Polyplexes using 25-kDa polyethylenimine (PEI) and plasmid encoding green fluorescent protein (GFP) were delivered to HEK 293T cells. After treating cells with polyplexes, microarrays were used to identify endogenous genes differentially expressed between treated and untreated cells (2 h of exposure) or between flow-separated transfected cells (GFP+) and treated, untransfected cells (GFP–) at 8, 16 and 24 h after lipoplex treatment. Cell priming studies were conducted using pharmacologic agents to alter endogenous levels of the identified differentially expressed genes …


Temporal Endogenous Gene Expression Profiles In Response To Lipid-Mediated Transfection, Timothy M. Martin, Sarah A. Plautz, Angela K. Pannier Jan 2015

Temporal Endogenous Gene Expression Profiles In Response To Lipid-Mediated Transfection, Timothy M. Martin, Sarah A. Plautz, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background — Design of efficient nonviral gene delivery systems is limited as a result of the rudimentary understanding of the specific molecules and processes that facilitate DNA transfer.

Methods — Lipoplexes formed with Lipofectamine 2000 (LF2000) and plasmid-encoding green fluorescent protein (GFP) were delivered to the HEK 293T cell line. After treating cells with lipoplexes, HG-U133 Affymetrix microarrays were used to identify endogenous genes differentially expressed between treated and untreated cells (2 h exposure) or between flow-separated transfected cells (GFP+) and treated, untransfected cells (GFP–) at 8, 16 and 24 h after lipoplex treatment. Cell priming studies were conducted using …


Robust And Flexible Films From 100% Starch Cross-Linked By Biobased Disaccharide Derivative, Helan Xu, Hazal Canisag, Bingnan Mu, Yiqi Yang Jan 2015

Robust And Flexible Films From 100% Starch Cross-Linked By Biobased Disaccharide Derivative, Helan Xu, Hazal Canisag, Bingnan Mu, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In this research, oxidized sucrose, a novel aldehyde-based green cross-linker, endowed starch films with substantial improvement in both tensile strength and elongation, whereas many other cross-linkers did not. Starch films are usually weak, brittle, and highly moisture sensitive, and thus have restricted industrial applications. Cross-linking is one of the most common methods to tackle these problems. However, most of the available cross-linkers are either toxic, expensive, or with low cross-linking efficiencies. Oxidized sucrose is a green cross-linker with multiple aldehyde groups per molecule to cross-link starch molecules via forming hemiacetals/acetals. The starch films cross-linked with oxidized sucrose had tensile strength …


Bionanotechnology And The Future Of Glioma, Peter A. Chiarelli, Forrest M. Kievit, Miqin Zhang, Richard G. Ellenbogen Jan 2015

Bionanotechnology And The Future Of Glioma, Peter A. Chiarelli, Forrest M. Kievit, Miqin Zhang, Richard G. Ellenbogen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Designer nanoscaled materials have the potential to revolutionize diagnosis and treatment for glioma. This review summarizes current progress in nanoparticle‑based therapies for glioma treatment including targeting, drug delivery, gene delivery, and direct tumor ablation. Preclinical and current human clinical trials are discussed. Although progress in the field has been significant over the past decade, many successful strategies demonstrated in the laboratory have yet to be implemented in human clinical trials. Looking forward, we provide examples of combined treatment strategies, which harness the potential for nanoparticles to interact with their biochemical environment, and simultaneously with externally applied photons or magnetic fields. …


Integrating Ecological And Engineering Concepts Of Resilience In Microbial Communities, Hyun-Seob Song, Ryan S. Renslow, Jim K. Fredrickson, Stephen R. Lindemann Jan 2015

Integrating Ecological And Engineering Concepts Of Resilience In Microbial Communities, Hyun-Seob Song, Ryan S. Renslow, Jim K. Fredrickson, Stephen R. Lindemann

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Many definitions of resilience have been proffered for natural and engineered ecosystems, but a conceptual consensus on resilience in microbial communities is still lacking. We argue that the disconnect largely results from the wide variance in microbial community complexity, which range from compositionally simple synthetic consortia to complex natural communities, and divergence between the typical practical outcomes emphasized by ecologists and engineers. Viewing microbial communities as elasto-plastic systems that undergo both recoverable and unrecoverable transitions, we argue that this gap between the engineering and ecological definitions of resilience stems from their respective emphases on elastic and plastic deformation, respectively. We …


Surface Energy Balance, Evapotranspiration, And Surface Coefficients During Non-Growing Season In A Maize-Soybean Cropping System, Lameck O. Odhiambo, Suat Irmak Jan 2015

Surface Energy Balance, Evapotranspiration, And Surface Coefficients During Non-Growing Season In A Maize-Soybean Cropping System, Lameck O. Odhiambo, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Surface energy balance components, including actual evapotranspiration (ET), were measured in a reducedtill maize-soybean field in south central Nebraska during three consecutive non-growing seasons (2006/2007, 2007/2008, and 2008/2009). The relative fractions of the energy balance components were compared across the non-growing seasons, and surface coefficients (Kc) were determined as a ratio of measured ET to estimated alfalfa (ETr) and grass (ETo) reference ET (ETref). The non-growing season following a maize crop had 25% to 35% more field surface covered with crop residue as compared to the non-growing seasons following soybean crops. Net …


Control System Development And Response Analysis Of An Electronically Actuated Variable-Orifice Nozzle For Agricultural Pesticide Applications, Joe D. Luck, S. A. Shearer, M. P. Sama, Santosh Pitla Jan 2015

Control System Development And Response Analysis Of An Electronically Actuated Variable-Orifice Nozzle For Agricultural Pesticide Applications, Joe D. Luck, S. A. Shearer, M. P. Sama, Santosh Pitla

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this research project was to further the development of an electromechanically controlled variable-orifice nozzle by creating an electronic control system and then evaluating that system based on step and ramp inputs. The control system was developed in a programming environment that combined an electronic data acquisition system and actuator with pressure and flow sensors. A proportional, variable-gain (based on system pressure) control system was developed to adjust nozzle flow rates to meet target application rates. The constraints were to achieve settling time of less than 1.0 s, overshoot of less than 10% of maximum flow (or minimum …


Flow, Spray Pattern, And Droplet Spectra Characteristics Of An Electronically Actuated Variable-Orifice Nozzle, Joe D. Luck, Santosh Pitla, M. P. Sama, S. A. Shearer Jan 2015

Flow, Spray Pattern, And Droplet Spectra Characteristics Of An Electronically Actuated Variable-Orifice Nozzle, Joe D. Luck, Santosh Pitla, M. P. Sama, S. A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The purpose of this study was to develop and evaluate the flow rate, spray pattern, and droplet spectra characteristics of an actively controlled variable-orifice nozzle at constant carrier pressures. A commercially available variable- orifice nozzle (VariTarget) was modified to allow for direct electromechanical control of the metering stem. The modified system was tested at five carrier pressures ranging from 138 to 414 kPa and five metering stem (and thus orifice) positions. The metering stem position range was chosen because it provided a linear response in flow rate at each carrier pressure. Flow rate testing indicated a turndown ratio of 2.4:1 …


Evaluation Of Sixteen Reference Evapotranspiration Methods Under Sahelian Conditions In The Senegal River Valley, Koffi Djaman, Alpha B. Balde, Abdoulaye Sow, Bertrand Muller, Suat Irmak, Mamadou K. N'Diaye, Baboucarr Manneh, Yonnelle D. Moukoumbi, Koichi Futakuchi, Kazuki Saito Jan 2015

Evaluation Of Sixteen Reference Evapotranspiration Methods Under Sahelian Conditions In The Senegal River Valley, Koffi Djaman, Alpha B. Balde, Abdoulaye Sow, Bertrand Muller, Suat Irmak, Mamadou K. N'Diaye, Baboucarr Manneh, Yonnelle D. Moukoumbi, Koichi Futakuchi, Kazuki Saito

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Study region: Reference evapotranspiration (ETo) plays a key role in irrigation sys-tems design, water management under irrigated and rainfed production. Underthe sahelian conditions in the Senegal River Valley that receives less than 300 mmannual rainfall, rice crop water use should be estimated for the sustainability of theresource. Study focus: However the Penman–Monteith (PM) equation is revealed the mostaccurate one; it necessitates several climatic parameters that are not always avail-able mostly in the developing countries. The objective of this study was to evaluatethe performance of 16 ETo equations against the ASCE-PM equation under thesahelian conditions at Ndiaye and Fanaye …


Robust Estimates Of Soil Moisture And Latent Heat Flux Coupling Strength Obtained From Triple Collocation, Wade T. Crow, Fangni Lei, Christopher R. Hain, Martha C. Anderson, Russell L. Scott, David P. Billesbach, Timothy Arkebauer Jan 2015

Robust Estimates Of Soil Moisture And Latent Heat Flux Coupling Strength Obtained From Triple Collocation, Wade T. Crow, Fangni Lei, Christopher R. Hain, Martha C. Anderson, Russell L. Scott, David P. Billesbach, Timothy Arkebauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Land surface models (LSMs) are often applied to predict the one-way coupling strength between surface soil moisture (SM) and latent heat (LH) flux. However, the ability of LSMs to accurately represent such coupling has not been adequately established. Likewise, the estimation of SM/LH coupling strength using ground-based observational data is potentially compromised by the impact of independent SM and LH measurements errors. Here we apply a new statistical technique to acquire estimates of one-way SM/LH coupling strength which are nonbiased in the presence of random error using a triple collocation approach based on leveraging the simultaneous availability of independent SM …


Using Swat To Simulate Crop Yields And Salinity Levels In The North Fork River Basin, Usa, Aaron R. Mittelstet, Daniel E. Storm, Art L. Stoecker Jan 2015

Using Swat To Simulate Crop Yields And Salinity Levels In The North Fork River Basin, Usa, Aaron R. Mittelstet, Daniel E. Storm, Art L. Stoecker

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop yields and salinity levels in the North Fork of the Red River (North Fork River) basin, located in southwestern Oklahoma and the Texas Panhandle, were analyzed based on the diverse climate in the region. Saline irrigation water is a major problem in the basin. The Elm Fork Creek flows through salt deposits, making the creek and its receiving stream, the North Fork River, too saline to use for irrigation. This greatly reduces the number of hectares that can be utilized for agricultural crops within the basin. A baseline SWAT model was setup, calibrated and validated to simulate streamflow and …


Identifying Intracellular Pdna Losses From A Model Of Nonviral Gene Delivery, Timothy Michael Martin, Beata Joanna Wysocki, Tadeusz Antoni Wysocki, Angela K. Pannier Jan 2015

Identifying Intracellular Pdna Losses From A Model Of Nonviral Gene Delivery, Timothy Michael Martin, Beata Joanna Wysocki, Tadeusz Antoni Wysocki, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nonviral gene delivery systems are a type of nanocommunication system that transmit plasmid packets (i.e., pDNA packets) that are programmed at the nanoscale to biological systems at the microscopic cellular level. This engineered nanocommunication system suffers large pDNA losses during transmission of the genetically encoded information, preventing its use in biotechnological and medical applications. The pDNA losses largely remain uncharacterized, and the ramifications of reducing pDNA loss from newly designed gene delivery systems remain difficult to predict. Here, the pDNA losses during primary and secondary transmission chains were identified utilizing a MATLAB model employing queuing theory simulating delivery of pEGFPLuc …


Narrow Grass Hedges Reduce Tylosin And Associated Antimicrobial Resistance Genes In Agricultural Runoff, Bhavneet Soni, Shannon L. Bartelt-Hunt, Daniel D. Snow, John E. Gilley, Bryan Woodbury, David B. Marx, Xu Li Jan 2015

Narrow Grass Hedges Reduce Tylosin And Associated Antimicrobial Resistance Genes In Agricultural Runoff, Bhavneet Soni, Shannon L. Bartelt-Hunt, Daniel D. Snow, John E. Gilley, Bryan Woodbury, David B. Marx, Xu Li

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Agricultural runoff from areas receiving livestock manure can potentially contaminate surface water with antimicrobials and antimicrobial resistance genes (ARGs). The objective of this study was to investigate the effectiveness of narrow grass hedges (NGHs) on reducing the transport of antimicrobials and ARGs in runoff after land application of swine manure slurry. Plot-scale rainfall simulation tests were conducted on 0.75 m by 4.0 m plots designed to test three treatment factors: manure amendment (control plots receiving no manure vs. amended plots receiving manure based on 3 times N requirement), NGH (plots with a NGH vs. plots without a NGH), and rainfall …


Vulnerability Of Crops And Native Grasses To Summer Drying In The U.S. Southern Great Plains, Naama Raz-Yaseef, Dave P. Billesbach, Marc L. Fischer, Sebastien C. Biraud, Stacey A. Gunter, James A. Bradford, Margaret S. Torn Jan 2015

Vulnerability Of Crops And Native Grasses To Summer Drying In The U.S. Southern Great Plains, Naama Raz-Yaseef, Dave P. Billesbach, Marc L. Fischer, Sebastien C. Biraud, Stacey A. Gunter, James A. Bradford, Margaret S. Torn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Southern Great Plains are characterized by a fine-scale mixture of different land-cover types, predominantly winter-wheat and grazed pasture, with relatively small areas of other crops, native prairie, and switchgrass. Recent droughts and predictions of increased drought in the Southern Great Plains, especially during the summer months, raise concern for these ecosystems. We measured ecosystem carbon and water fluxes with eddy-covariance systems over cultivated cropland for 10 years, and over lightly grazed prairie and new switchgrass fields for 2 years each. Growing-season precipitation showed the strongest control over net carbon uptake for all ecosystems, but with a variable effect: grasses …


A Sustainable Slashing Industry Using Biodegradable Sizes From Modified Soy Protein To Replace Petro-Based Poly(Vinyl Alcohol), Yi Zhao, Yuzhu Zhao, Helan Xu, Yiqi Yang Jan 2015

A Sustainable Slashing Industry Using Biodegradable Sizes From Modified Soy Protein To Replace Petro-Based Poly(Vinyl Alcohol), Yi Zhao, Yuzhu Zhao, Helan Xu, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biodegradable sizing agents from triethanolamine (TEA) modified soy protein could substitute poly(vinyl alcohol)(PVA) sizes for high-speed weaving of polyester and polyester/cotton yarns to substantially decrease environmental pollution and impel sustainability of textile industry. Nonbiodegradable PVA sizes are widely used and mainly contribute to high chemical oxygen demand (COD) in textile effluents. It has not been possible to effectively degrade, reuse or replace PVA sizes so far. Soy protein with good biodegradability showed potential as warp sizes in our previous studies. However, soy protein sizes lacked film flexibility and adhesion for required high-speed weaving. Additives with multiple hydroxyl groups, nonlinear molecule, …


Sustainable And Hydrolysis-Free Dyeing Process For Polylactic Acid Using Nonaqueous Medium, Suxin Xu, Jiangang Chen, Bijia Wang, Yiqi Yang Jan 2015

Sustainable And Hydrolysis-Free Dyeing Process For Polylactic Acid Using Nonaqueous Medium, Suxin Xu, Jiangang Chen, Bijia Wang, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A sustainable and hydrolysis-free dyeing process was developed for polylactic acid (PLA) fibers. PLA is a biobased alternative to petroleum based polyethylene terephthalate (PET), which is the most widely used textile fiber. However, the hydrolytic degradation of PLA fibers under the conventional aqueous dyeing conditions limited its applications in textile industry. A new solvent dyeing process was developed using liquid paraffin as a nonaqueous dyeing medium. High quality dyed PLA fabrics were obtained without consuming water and auxiliaries. Minimal strength loss of dyed fibers was achieved by postheat setting treatment. The 3R principle (reduce, reuse, and recycle) was implemented to …


Chitosan-Alginate Scaffold Cell Culture System And Related Methods, Miqin Zhang, Forrest Kievit, Matthew Chi-Hang Leung, Stephen Florczyk Jan 2015

Chitosan-Alginate Scaffold Cell Culture System And Related Methods, Miqin Zhang, Forrest Kievit, Matthew Chi-Hang Leung, Stephen Florczyk

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Methods for culturing cancer cells in vitro using a three dimensional scaffold, scaffolds that include the cultured cancer cells, and methods for using the cultured cancer cells and the scaffolds that include the cultured cancer cells in anticancer therapeutic drug development.


Nanoparticle Mediated Silencing Of Dna Repair Sensitizes Pediatric Brain Tumor Cells To Y-Irradiation, Forrest M. Kievit, Zachary R. Stephen, Kui Wang, Christopher J. Dayringer, Jonathan G. Sham, Richard G. Ellenbogen, John R. Silber, Miqin Zhang Jan 2015

Nanoparticle Mediated Silencing Of Dna Repair Sensitizes Pediatric Brain Tumor Cells To Y-Irradiation, Forrest M. Kievit, Zachary R. Stephen, Kui Wang, Christopher J. Dayringer, Jonathan G. Sham, Richard G. Ellenbogen, John R. Silber, Miqin Zhang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Medulloblastoma (MB) and ependymoma (EP) are the most common pediatric brain tumors, afflicting 3000 children annually. Radiotherapy (RT) is an integral component in the treatment of these tumors; however, the improvement in survival is often accompanied by radiation-induced adverse developmental and psychosocial sequelae. Therefore, there is an urgent need to develop strategies that can increase the sensitivity of brain tumors cells to RT while sparing adjacent healthy brain tissue. Apurinic endonuclease 1 (Ape1), an enzyme in the base excision repair pathway, has been implicated in radiation resistance in cancer. Pharmacological and specificity limitations inherent to small molecule inhibitors of Ape1 …


Color Removal From Pulp Mill Effluent Using Coal Ash Produced From Georgia Power Coal Combustion Plants, Christopher B. Willett Jan 2015

Color Removal From Pulp Mill Effluent Using Coal Ash Produced From Georgia Power Coal Combustion Plants, Christopher B. Willett

College of Graduate Studies: Theses & Dissertations

Two environmental concerns currently face Georgia: coal fly ash (CFA) waste from coal power plants, and the effluent generated by pulp mills. Pulp mill effluent discolors surface waters into which it is discharged, and has been proven to negatively impact the dissolved oxygen and carbon necessary for aquatic life. The proposed solution is a cost-effective adsorption treatment using an inexpensive but abundantly available waste material: CFA. CFA possesses beneficial properties that allow it to effectively remove contaminants, and is available at significantly reduced cost. The primary research objective was to define treatment parameters that would result in the maximum removal …


Underwater Sound Transmission Through Arrays Of Disk Cavities In A Soft Elastic Medium, David C. Calvo, Abel L. Thangawng, Christopher N. Layman Jr., Riccardo Casalini, Shadi F. Othman Jan 2015

Underwater Sound Transmission Through Arrays Of Disk Cavities In A Soft Elastic Medium, David C. Calvo, Abel L. Thangawng, Christopher N. Layman Jr., Riccardo Casalini, Shadi F. Othman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Scattering from a cavity in a soft elastic medium, such as silicone rubber, resembles scattering from an underwater bubble in that low-frequency monopole resonance is obtainable in both cases. Arrays of cavities can therefore be used to reduce underwater sound transmission using thin layers and low void fractions. This article examines the role of cavity shape by microfabricating arrays of disk-shaped air cavities into single and multiple layers of polydimethylsiloxane. Comparison is made with the case of equivalent volume cylinders which approximate spheres. Measurements of ultrasonic underwater sound transmission are compared with finite element modeling predictions. The disks provide a …


Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson Dec 2014

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …


United States Patent Application Publication, John H. Posselius, Christopher A. Foster, Santosh Pitla, Scott A. Shearer, Joe D. Luck, Michael P. Sama, Rodrigo S. Zandonadi Nov 2014

United States Patent Application Publication, John H. Posselius, Christopher A. Foster, Santosh Pitla, Scott A. Shearer, Joe D. Luck, Michael P. Sama, Rodrigo S. Zandonadi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A multiple robot control architecture including a plurality of robotic agricultural machines including a first and second robotic agricultural machine. Each robotic agricultural machine including at least one controller configured to implement a plurality of finite state machines Within an individual robot control architecture (IRCA) and a global information module (GIM) communicatively coupled to the IRCA. The GIMs of the first and second robotic agricultural machines being configured to cooperate to cause said first robotic agricultural machine and said second agricultural machine to perform at least one agricultural task.


Soil Carbon Accumulation Under Switchgrass Barriers, Humberto Blanco-Canqui, John E. Gilley, Dean E. Eisenhauer, Paul J. Jasa, Alan L. Boldt Oct 2014

Soil Carbon Accumulation Under Switchgrass Barriers, Humberto Blanco-Canqui, John E. Gilley, Dean E. Eisenhauer, Paul J. Jasa, Alan L. Boldt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The benefits of grass barriers or hedges for reducing offsite transport of non-point-source water pollutants from croplands are well recognized, but their ancillary benefits on soil properties have received less attention. We studied the 15-yr cumulative effects of narrow and perennial switchgrass (Panicum virgatum L.) barriers on soil organic C (SOC), total N, particulate organic matter (POM), and associated soil structural properties as compared with the cropped area on an Aksarben silty clay loam (fine, smectitic, mesic Typic Argiudoll) with 5.4% slope in eastern Nebraska. Five switchgrass barriers were established in 1998 at ~38-m intervals parallel to the crop rows …


Emission Of Volatile Organic Compounds After Land Application Of Cattle Manure, Bryan Woodbury, John E. Gilley, David B. Parker, David B. Marx, Daniel N. Miller, Roger A. Eigenberg Jul 2014

Emission Of Volatile Organic Compounds After Land Application Of Cattle Manure, Bryan Woodbury, John E. Gilley, David B. Parker, David B. Marx, Daniel N. Miller, Roger A. Eigenberg

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Beef cattle manure can serve as a valuable source of nutrients for crop production. However, emissions of volatile organic compounds (VOCs) after land application may pose an odor nuisance to downwind populations. This study was conducted to evaluate the effects of land application method, diet, soil moisture content, and time since manure application on VOC emissions. Manure was collected from feedlot pens where cattle were fed diets containing 0, 10, or 30% wet distillers grains with solubles (WDGS). Land application methods included surface-applying manure (i.e., no-tillage) or incorporating manure using disk tillage. The effects of soil moisture content on VOC …


Integration Of Models For Low Carbon Economy, Getachew F. Belete, Alexey Voinov Jun 2014

Integration Of Models For Low Carbon Economy, Getachew F. Belete, Alexey Voinov

International Congress on Environmental Modelling and Software

Designing the transition to low carbon economy is a very complex task that touches upon a wide variety of climate-energy-economic systems. We need to explore the various possible climate mitigation scenarios at different temporal and spatial scales. However, due to the diversity of the involved disciplines it is difficult to find one complete and unified modeling approach that works equally well in all those different domains. As a result we have to select 'appropriate' models, which represent only specific aspects of the scenarios and assemble them 'coherently'. In this research we have identified some challenges in integrating multidisciplinary models; and …


A Decision Support System Approach For Identifying Poliutant Source For Optimization Of Beneficial Management Practices Scenario Modelling In Lake Winnipeg Watersheds, Isaac Wong, Luis Leon, Jason Vanrobaeys, Craig Mccrimmon, Phil Fong Jun 2014

A Decision Support System Approach For Identifying Poliutant Source For Optimization Of Beneficial Management Practices Scenario Modelling In Lake Winnipeg Watersheds, Isaac Wong, Luis Leon, Jason Vanrobaeys, Craig Mccrimmon, Phil Fong

International Congress on Environmental Modelling and Software

The Soil and Water Assessment Tool (SWAT) results can be used to source trace loading "hotspots• for optimally locating beneficial management practices (BMP). It is possible to trace upstream and compute the relative contribution of each sub-basin to a point of interest, accounting for in-stream processes, reservoirs and point sources. A decision support system (DSS) framework was developed to run SWAT, perform the otherwise tedious process of source tracing "hotspots" and to optimize BMP locations. The "Crop to Hay- land use change BMP scenario was applied in an attempt to reduce annual loadings of total phosphorus (TP) for three Lake …


Agroecosystem-Watershed (Ages-W) Model Delineation And Scaling, Timothy R. Green, Robert H. Erskine, James C. Ascough Ii, Bruce Vandenberg, Björn Pfennig, Holm Kipka, Olaf David, Micheal L. Coleman Jun 2014

Agroecosystem-Watershed (Ages-W) Model Delineation And Scaling, Timothy R. Green, Robert H. Erskine, James C. Ascough Ii, Bruce Vandenberg, Björn Pfennig, Holm Kipka, Olaf David, Micheal L. Coleman

International Congress on Environmental Modelling and Software

Water movement and storage within an agricultural watershed can be simulated at different spatial resolutions of land areas or hydrological response units (HRUs). Interactions between HRUs in space and time vary with the HRU sizes, such that natural scaling relationships are confounded with the simulation scales. Scaling concepts can be tested using the AgroEcoSystem­ Watershed (AgES-W) model with different resolutions of HRUs. Here, we delineated a 56-ha agricultural watershed in northern Colorado, USA farmed primarily under a wheat-fallow rotation. Factors used to distinguish HRUs included topography (surface flow paths), land use (crop strips and native grass), and mapped soil units …


Global Sensitivity Analysis Of Key Parameters In A Process-Based Sugarcane Growth Model - A Bayesian Approach, Justin Sexton, Yvette Everingham Jun 2014

Global Sensitivity Analysis Of Key Parameters In A Process-Based Sugarcane Growth Model - A Bayesian Approach, Justin Sexton, Yvette Everingham

International Congress on Environmental Modelling and Software

While several statistical methods are available to analyse model sensitivity, their application to complex process-based models is often impractical due to the large number of simulation runs required. A Bayesian approach to global sensitivity analysis can greatly reduce the number of simulation runs required by building an emulator of the model which is less computationally demanding. A Gaussian Emulation Machine (GEM) was used to efficiently assess the sensitivity of key agronomic outputs from the APSIM-Sugar crop model to influential input parameters. The sensitivity of simulated biomass and sucrose at harvest was assessed on 14 parameters representing varietal differences and growth …


Dynamic Feedback Between Land Use And Hydrology For Ecosystem Services Assessment, Seleshi Getahun Yalew, Tobias Pilz, Christian Schweitzer, Stefan Liersch, Johannes Van Der Kwast, Marloes L. Mul, Ann Van Griensven, Pieter Van Der Zaag Jun 2014

Dynamic Feedback Between Land Use And Hydrology For Ecosystem Services Assessment, Seleshi Getahun Yalew, Tobias Pilz, Christian Schweitzer, Stefan Liersch, Johannes Van Der Kwast, Marloes L. Mul, Ann Van Griensven, Pieter Van Der Zaag

International Congress on Environmental Modelling and Software

Ecosystem services assessment requires an integrated approach, as it is influenced by elements such as climate, hydrology and socio-economics, which in turn influence each other. However, there are few studies that integrate these elements in order to assess ecosystem services. Absence of integrated approach to modelling hydrological and land-use changes, for instance, often oversights the dynamic feedback between the two processes. Dynamic changes in land-use should be fed into hydrological models and vice-versa at each time-step for a more realistic representation. In this study, this approach is demonstrated with a case study of the uThukela catchment, South Africa. There is …