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Articles 81631 - 81660 of 196716

Full-Text Articles in Engineering

Integration Of Biology, Ecology And Engineering For Sustainable Algal‑Based Biofuel And Bioproduct Biorefinery, James Allen, Serpil Unlu, Yaşar Demirel, Paul N. Black, Wayne R. Riekhof Jan 2018

Integration Of Biology, Ecology And Engineering For Sustainable Algal‑Based Biofuel And Bioproduct Biorefinery, James Allen, Serpil Unlu, Yaşar Demirel, Paul N. Black, Wayne R. Riekhof

Department of Chemical and Biomolecular Engineering: Faculty Publications

Despite years of concerted research efforts, an industrial-scale technology has yet to emerge for production and conversion of algal biomass into biofuels and bioproducts. The objective of this review is to explore the ways of possible integration of biology, ecology and engineering for sustainable large algal cultivation and biofuel production systems. Beside the costs of nutrients, such as nitrogen and phosphorous, and fresh water, upstream technologies which are not ready for commercialization both impede economic feasibility and conflict with the ecological benefits in the sector. Focusing mainly on the engineering side of chemical conversion of algae to biodiesel has also …

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Irrigation Pumps - Preserving Performance, Derrel L. Martin Jan 2018

Irrigation Pumps - Preserving Performance, Derrel L. Martin

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

This paper describes how pumps must be matched to operating conditions and power units to provide the desired performance and efficiency. We have recently seen installations where one or more components are not properly matched causing higher than necessary pumping costs. Inspection and maintenance of systems and measurement of flow and pressure will go a long way toward monitoring if the proper conditions are being met. This paper also covers types of pumps, pump components, pump curves, impeller speed and trim, pump staging, affinity laws, pump drives, power units, cavitation, and net positive suction head.

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Detection Of Multi-Tomato Leaf Diseases (Late Blight, Target And Bacterial Spots) In Different Stages By Using A Spectral-Based Sensor, Jinzhu Lu, Reza Ehsani, Yeyin Shi, Ana Isabel De Castro, Shuang Wang Jan 2018

Detection Of Multi-Tomato Leaf Diseases (Late Blight, Target And Bacterial Spots) In Different Stages By Using A Spectral-Based Sensor, Jinzhu Lu, Reza Ehsani, Yeyin Shi, Ana Isabel De Castro, Shuang Wang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Several diseases have threatened tomato production in Florida, resulting in large losses, especially in fresh markets. In this study, a high-resolution portable spectral sensor was used to investigate the feasibility of detecting multi-diseased tomato leaves in different stages, including early or asymptomatic stages. One healthy leaf and three diseased tomato leaves (late blight, target and bacterial spots) were defined into four stages (healthy, asymptomatic, early stage and late stage) and collected from a field. Fifty-seven spectral vegetation indices (SVIs) were calculated in accordance with methods published in previous studies and established in this study. Principal component analysis was …

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Evaluation Of Variable Rate Irrigation Using A Remote-Sensing-Based Model, John Burdette Barker, Derek M. Heeren, Christopher M.U. Neale, Daran Rudnick Jan 2018

Evaluation Of Variable Rate Irrigation Using A Remote-Sensing-Based Model, John Burdette Barker, Derek M. Heeren, Christopher M.U. Neale, Daran Rudnick

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Improvements in soil water balance modeling can be beneficial for optimizing irrigation management to account for spatial variability in soil properties and evapotranspiration (ET). A remote-sensing-based ET and water balance model was tested for irrigation management in an experiment at two University of Nebraska-Lincoln research sites located near Mead and Brule, Nebraska. Both fields included a center pivot equipped with variable rate irrigation (VRI). The study included maize in 2015 and 2016 and soybean in 2016 at Mead, and maize in 2016 at Brule, for a total of 210 plot-years. Four irrigation treatments were applied at Mead, including: VRI based …

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Integration Of Hydrogeophysical Datasets And Empirical Orthogonal Functions For Improved Irrigation Water Management, Catherine E. Finkenbiner, Trenton E. Franz, Justin P. Gibson, Derek M. Heeren, J. D. Luck Jan 2018

Integration Of Hydrogeophysical Datasets And Empirical Orthogonal Functions For Improved Irrigation Water Management, Catherine E. Finkenbiner, Trenton E. Franz, Justin P. Gibson, Derek M. Heeren, J. D. Luck

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Precision agriculture offers the technologies to manage for infield variability and incorporate variability into irrigation management decisions. The major limitation of this technology often lies in the reconciliation of disparate data sources and the generation of irrigation prescription maps. Here the authors explore the utility of the cosmic-ray neutron probe (CRNP) which measures volumetric soil water content (SWC) in the top ~ 30 cm of the soil profile. The key advantages of CRNP is that the sensor is passive, non-invasive, mobile and soil temperature-invariant, making data collection more compatible with existing farm operations and extending the mapping period. The objectives …

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Dynamic Rops Test For Tractors Over 6,000 Kilograms, Caleb M. Lindhorst, Roger M. Hoy, Santosh Pitla, Michael F. Kocher Jan 2018

Dynamic Rops Test For Tractors Over 6,000 Kilograms, Caleb M. Lindhorst, Roger M. Hoy, Santosh Pitla, Michael F. Kocher

Department of Agricultural and Biological Systems Engineering: Faculty Publications

OECD static tests (Codes 4, 6, 7, and 8) for agricultural rollover protective structures (ROPS) have become accepted standards for evaluating the ability of these structures to protect the operator during tractor rollover events. The strength properties of some materials typically used in ROPS change because of cold weather embrittlement at low temperatures. The static ROPS tests lack the ability to evaluate the strength of these structures during cold weather. The use of the dynamic ROPS test is well noted as a means for proving cold weather embrittlement resistance properties. Unfortunately, application of the OECD dynamic ROPS test (Code 3) …

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The Open Source Gaitor Suite For Rodent Gait Analysis, Brittany Y. Jacobs, Emily H. Lakes, Alex J. Reiter, Spencer P. Lake, Trevor R. Ham, Nic D. Leipzig, Stacy L. Porvasnik, Christine E. Schmidt, Rebecca A. Wachs, Kyle D. Allen Jan 2018

The Open Source Gaitor Suite For Rodent Gait Analysis, Brittany Y. Jacobs, Emily H. Lakes, Alex J. Reiter, Spencer P. Lake, Trevor R. Ham, Nic D. Leipzig, Stacy L. Porvasnik, Christine E. Schmidt, Rebecca A. Wachs, Kyle D. Allen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Locomotive changes are often associated with disease or injury, and these changes can be quantified through gait analysis. Gait analysis has been applied to preclinical studies, providing quantitative behavioural assessment with a reasonable clinical analogue. However, available gait analysis technology for small animals is somewhat limited. Furthermore, technological and analytical challenges can limit the effectiveness of preclinical gait analysis. The Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) Suite is designed to increase the accessibility of preclinical gait analysis to researchers, facilitating hardware and software customization for broad applications. Here, the GAITOR Suite’s utility is demonstrated in 4 models: …

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Greenhouse Gas Emissions From Beef Feedlot Surface Materials As Affected By Diet, Moisture, Temperature, And Time, Bryan L. Woodbury, John E. Gilley, David B. Parker, Bobbi S. Stomer Jan 2018

Greenhouse Gas Emissions From Beef Feedlot Surface Materials As Affected By Diet, Moisture, Temperature, And Time, Bryan L. Woodbury, John E. Gilley, David B. Parker, Bobbi S. Stomer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A laboratory study was conducted to measure the effects of diet, moisture, temperature, and time on greenhouse gas (GHG) emissions from feedlot surface materials (FSM). The FSM were collected from open-lot pens where beef cattle were fed either a dry-rolled corn (DRC) diet containing no wet distillers grains with solubles (WDGS) or a DRC diet containing 35% WDGS. The FSM were collected, air-dried or mixed with 3.0 L of water to represent dry or wet conditions, and then incubated at temperatures of 5°C, 15°C, 25°C, or 35°C. Static flux chambers were used to quantify GHG emissions over a 14-day period. …

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Surface Detention On Cropland, Rangeland, And Conservation Reserve Program Areas, John E. Gilley Jan 2018

Surface Detention On Cropland, Rangeland, And Conservation Reserve Program Areas, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

One of the factors contributing to overland flow on upland areas is water stored temporarily in a thin sheet on the soil surface as surface detention. This study was conducted to quantify surface detention on selected cropland, rangeland, and Conservation Reserve Program (CRP) sites. Surface detention was determined from the recession portion of runoff hydrographs corresponding with the period when rainfall had ceased but runoff continued. The hydrographs were generated from six previously reported rainfall simulation studies conducted on paired 3.7 m wide  10.7 m long plots on which approximately 128 mm of rainfall was applied. Surface detention values …

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Evaluation Of The Accuracy Of Machine Reported Can Data For Engine Torque And Speed (J1939), Rodney A. Rohrer, Joe D. Luck, Santosh K. Pitla, Roger M. Hoy Jan 2018

Evaluation Of The Accuracy Of Machine Reported Can Data For Engine Torque And Speed (J1939), Rodney A. Rohrer, Joe D. Luck, Santosh K. Pitla, Roger M. Hoy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Most modern off-road machinery use embedded electronic controllers connected to a controller area network (CAN) to broadcast machine information for on-board processes and diagnostics. Commercially available tools can record CAN data for a variety of research and commercial uses. For agricultural tractors, there is an opportunity to create advanced test procedures that are more representative of field operations and that could supplement existing machine performance tests, such as the OECD Code 2 Standard Code for the Official Testing of Agricultural and Forestry Tractor Performance. CAN parameters provide an efficient way to collect tractor performance data during field operations. However, the …

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Prediction Of Agricultural Implement Hydraulic Power Requirements Using Controller Area Network Bus Data, Gabriel P. Stoll, Rodney A. Rohrer, Santosh K. Pitla, Joe D. Luck Jan 2018

Prediction Of Agricultural Implement Hydraulic Power Requirements Using Controller Area Network Bus Data, Gabriel P. Stoll, Rodney A. Rohrer, Santosh K. Pitla, Joe D. Luck

Department of Agricultural and Biological Systems Engineering: Faculty Publications

One of the important challenges in agricultural machinery research is the ability to effectively determine power requirements of a given field operation. The Controller Area Network (CAN) Bus, also known as ISOBUS, has proven to be an effective digital tool for tractor and implement data collection. This study attempted to determine implement hydraulic power requirements using a combination of existing public tractor CAN messages and minimal added sensors. The sensor signals were published on the CAN bus for ease of simultaneous sensor signal and CAN message data collection. Based upon the available CAN messages, this study attempted to measure hydraulic …

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Effects Of Alternate Wetting And Drying Irrigation Regime And Nitrogen Fertilizer On Yield And Nitrogen Use Efficiency Of Irrigated Rice In The Sahel, Koffi Djaman, Valere C. Mel, Lamine Diop, Abdoulaye Sow, Raafat El-Namaky, Baboucarr Manneh, Kazuki Saito, Koichi Futakuchi, Suat Irmak Jan 2018

Effects Of Alternate Wetting And Drying Irrigation Regime And Nitrogen Fertilizer On Yield And Nitrogen Use Efficiency Of Irrigated Rice In The Sahel, Koffi Djaman, Valere C. Mel, Lamine Diop, Abdoulaye Sow, Raafat El-Namaky, Baboucarr Manneh, Kazuki Saito, Koichi Futakuchi, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The objectives of this study were to investigate water saving strategies in the paddy field and to evaluate the performance of some of the newly released rice varieties. Field experiments were conducted at Fanaye in the Senegal River Valley during two rice growing seasons in 2015. Three irrigation regimes ((i) continuous flooding, (ii) trigging irrigation at soil matric potential (SMP) of 30 kPa, (iii) trigging irrigation at SMP of 60 kPa) were tested in an irrigated lowland rice field. Irrigation regimes (ii) and (iii) are alternate wetting and drying (AWD) cycles. Four inbred rice varieties (NERICA S-21, NERICA S-44, Sahel …

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Crop Evapotranspiration, Irrigationwater Requirement And Water Productivity Of Maize From Meteorological Data Under Semiarid Climate, Koffi Djaman, Michael O'Neill, Curtis K. Owen, Daniel Smeal, Komlan Koudahe, Margaret West, Samuel Allen, Kevin Lombard, Suat Irmak Jan 2018

Crop Evapotranspiration, Irrigationwater Requirement And Water Productivity Of Maize From Meteorological Data Under Semiarid Climate, Koffi Djaman, Michael O'Neill, Curtis K. Owen, Daniel Smeal, Komlan Koudahe, Margaret West, Samuel Allen, Kevin Lombard, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Under the semiarid climate of the Southwest United States, accurate estimation of crop water use is important for water management and planning under conservation agriculture. The objectives of this study were to estimate maize water use and water productivity in the Four Corners region of New Mexico. Maize was grown under full irrigation during the 2011, 2012, 2013, 2014 and 2017 seasons at the Agricultural Science Center at Farmington (NM). Seasonal amounts of applied irrigation varied from 576.6 to 1051.6 mm and averaged 837.7 mm and the total water supply varied from 693.4 to 1140.5 mm. Maize actual evapotranspiration was …

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Hydrologic Evaluation Of Residential Rain Gardens Using A Stormwater Runoff Simulator, A. R. Anderson, T. G. Franti, D. P. Shelton Jan 2018

Hydrologic Evaluation Of Residential Rain Gardens Using A Stormwater Runoff Simulator, A. R. Anderson, T. G. Franti, D. P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Engineered bioretention cells with underdrains have shown water quality and hydrologic benefits for abating urban stormwater problems. Less is known about the hydrologic performance of residential rain gardens that rely on in situ soil infiltration as the primary mechanism of volume control. Eleven residential rain gardens in Lincoln, Nebraska, were evaluated using a variable-rate stormwater runoff simulator. A volume-based water quality volume (WQV) design storm of 3.0 cm was applied to each rain garden as an SCS Type II runoff hydrograph until the system began overflowing to test the rain gardens for surface and subsurface storage capacity, drawdown rate, ponding …

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Registration For Optical Multimodal Remote Sensing Images Based On Fast Detection,Window Selection, And Histogram Specification, Xiaoyang Zhao, Jian Zhang, Chenghai Yang, Huaibo Song, Yeyin Shi, Xingen Zhou, Dongyan Zhang, Guozhong Zhang Jan 2018

Registration For Optical Multimodal Remote Sensing Images Based On Fast Detection,Window Selection, And Histogram Specification, Xiaoyang Zhao, Jian Zhang, Chenghai Yang, Huaibo Song, Yeyin Shi, Xingen Zhou, Dongyan Zhang, Guozhong Zhang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In recent years, digital frame cameras have been increasingly used for remote sensing applications. However, it is always a challenge to align or register images captured with different cameras or different imaging sensor units. In this research, a novel registration method was proposed. Coarse registration was first applied to approximately align the sensed and reference images. Window selection was then used to reduce the search space and a histogram specification was applied to optimize the grayscale similarity between the images. After comparisons with other commonly-used detectors, the fast corner detector, FAST (Features from Accelerated Segment Test), was selected to extract …

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Impact Of Eastern Redcedar Proliferation On Water Resources In The Great Plains Usa—Current State Of Knowledge, Chris B. Zou, Dirac Twidwell, Christine H. Bielski, Dillon T. Fogarty, Aaron R. Mittelstet, Patrick J. Starks, Rodney E. Will, Yu Zhong, Bharat Sharma Acharya Jan 2018

Impact Of Eastern Redcedar Proliferation On Water Resources In The Great Plains Usa—Current State Of Knowledge, Chris B. Zou, Dirac Twidwell, Christine H. Bielski, Dillon T. Fogarty, Aaron R. Mittelstet, Patrick J. Starks, Rodney E. Will, Yu Zhong, Bharat Sharma Acharya

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In the Great Plains of the central United States, water resources for human and aquatic life rely primarily on surface runoff and local recharge from rangelands that are under rapid transformation to woodland by the encroachment of Eastern redcedar (redcedar; Juniperus virginiana) trees. In this synthesis, the current understanding and impact of redcedar encroachment on the water budget and water resources available for non-ecosystem use are reviewed. Existing studies concluded that the conversion from herbaceous-dominated rangeland to redcedar woodland increases precipitation loss to canopy interception and vegetation transpiration. The decrease of soil moisture, particularly for the subsurface soil layer, …

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Investigation Of Organic Solvents’ Effects On Kenaf (Hibiscus Cannabinus L.) Biomass Conversion In Subcritical Water, Bahar Meryemoglu, Arif Hasanoglu, Mehtap Kurtulus, Sibel Irmak Jan 2018

Investigation Of Organic Solvents’ Effects On Kenaf (Hibiscus Cannabinus L.) Biomass Conversion In Subcritical Water, Bahar Meryemoglu, Arif Hasanoglu, Mehtap Kurtulus, Sibel Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Kenaf biomass was hydrolyzed under subcritical water conditions in the presence of various organic solvents. The solvents tested were tetrahydrofuran (THF), acetone, xylene (mixed isomers) and methanol. The organic compounds released into hydrolysates, total organic contents, water-soluble total phenols, and the molecular weight distributions of the polysaccharides in the hydrolysates, solid residues leftover after hydrolysis and gaseous products formed during the solubilization process were determined. The results showed that organic solvents significantly enhanced the dissolution of kenaf biomass (methanol < (omp)xylene ≤ acetone ~ tetrahydrofuran). The hydrolysis percentage was found to be between 75-82% depending on the type of the solvent. Hydrolysis yield and total organic carbons released into hydrolysates highly differed when the solubilization process was performed under carbon dioxide pressure and this effect considerably varied based on the type of solvent used in hydrolysis process. The main gas product formed during hydrolysis process was carbon dioxide with ~80% composition. Morphological measurements of the solid biomass residues left after hydrolysis showed substantial degradations with increasing number of pores on the biomass surfaces.

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Near Infrared Fluorescent Single Walled Carbon Nanotubes As Tissue Localizable Biosensors, Nicole M. Iverson, Michael S. Strano, Nigel F. Strano, Thomas P. Mcnicholas Jan 2018

Near Infrared Fluorescent Single Walled Carbon Nanotubes As Tissue Localizable Biosensors, Nicole M. Iverson, Michael S. Strano, Nigel F. Strano, Thomas P. Mcnicholas

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A nanosensor for detecting an analyte can include a sub strate, a photoluminescent nanostructure, and a polymer interacting with the photoluminescent nanostructure. The nanosensor can be used in in vivo for biomedical applications.

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Nitric Oxide Sensors For Biological Applications, Nicole M. Iverson, Eric M. Hofferber, Joseph A. Stapleton Jan 2018

Nitric Oxide Sensors For Biological Applications, Nicole M. Iverson, Eric M. Hofferber, Joseph A. Stapleton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nitric oxide (NO) is an essential signaling molecule within biological systems and is believed to be involved in numerous diseases. As a result of NO’s high reaction rate, the detection of the concentration of NO, let alone the presence or absence of the molecule, is extremely difficult. Researchers have developed multiple assays and probes in an attempt to quantify NO within biological solutions, each of which has advantages and disadvantages. This review highlights many of the current NO sensors, from those that are commercially available to the newest sensors being optimized in research labs, to assist in the understanding and …

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Evaluation Of Critical Nitrogen And Phosphorus Models For Maize Under Full And Limited Irrigation Conditions, Koffi Djaman, Suat Irmak Jan 2018

Evaluation Of Critical Nitrogen And Phosphorus Models For Maize Under Full And Limited Irrigation Conditions, Koffi Djaman, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Proper nitrogen (N) fertiliser application rates and timing of application, coupled with optimum irrigation management can improve the sustainability of maize production and reduce the risk of environmental contamination by nutrients. The impact of full and limited irrigation and rainfed conditions on in-season maize (Zea mays L.) shoot biomass nutrient concentration and critical N and phosphorus (P) indices were evaluated using a combination of measured nutrients and critical N and P models in south central Nebraska in 2009 and 2010. Four irrigation treatments [fully-irrigated treatment (FIT), 75% FIT, 60% FIT and 50% FIT) and rainfed] were imposed. Irrigation regimes …

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Phenotypic Responses To Interspecies Competition And Commensalism In A Naturally Derived Microbial Co-Culture, Nymul Khan, Yukari Maezato, Ryan S. Mcclure, Colin J. Brislawn, Jennifer M. Mobberley, Nancy Isern, William B. Chrisler, Lye Meng Markillie, Brett M. Barney, Hyun-Seob Song, William C. Nelson, Hans C. Bernstein Jan 2018

Phenotypic Responses To Interspecies Competition And Commensalism In A Naturally Derived Microbial Co-Culture, Nymul Khan, Yukari Maezato, Ryan S. Mcclure, Colin J. Brislawn, Jennifer M. Mobberley, Nancy Isern, William B. Chrisler, Lye Meng Markillie, Brett M. Barney, Hyun-Seob Song, William C. Nelson, Hans C. Bernstein

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The fundamental question of whether different microbial species will co-exist or compete in a given environment depends on context, composition and environmental constraints. Model microbial systems can yield some general principles related to this question. In this study we employed a naturally occurring co-culture composed of heterotrophic bacteria, Halomonas sp. HL-48 and Marinobacter sp. HL- 58, to ask two fundamental scientific questions: 1) how do the phenotypes of two naturally co-existing species respond to partnership as compared to axenic growth? and 2) how do growth and molecular phenotypes of these species change with respect to competitive and commensal interactions? We …

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Impact Of Vegetative Treatment Systems On Multiple Measures Of Antibiotic Resistance In Agricultural Wastewater, Lisa M. Durso, Daniel N. Miller, Christopher G. Henry Jan 2018

Impact Of Vegetative Treatment Systems On Multiple Measures Of Antibiotic Resistance In Agricultural Wastewater, Lisa M. Durso, Daniel N. Miller, Christopher G. Henry

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wastewater is an important vector of antibiotic resistant bacteria and antibiotic resistance genes (ARB/G). While there is broad agreement that ARB/G from agricultural (ag) wastewaters can be transported through the environment and may contribute to untreatable infectious disease in humans and animals, there remain large knowledge gaps surrounding applied details on the types and amounts of ARB/G associated with different agricultural wastewater treatment options and different ag production systems. This study evaluates a vegetative treatment system (VTS) built to treat the wastewater from a beef cattle feedlot. Samples were collected for three years, and plated on multiple media types to …

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Special Issue: Microbial Community Modeling: Prediction Of Microbial Interactions And Community Dynamics, Hyun-Seob Song Jan 2018

Special Issue: Microbial Community Modeling: Prediction Of Microbial Interactions And Community Dynamics, Hyun-Seob Song

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Microbial communities are networks of species, the interaction structure of which dynamically reorganizes in a varying environment. Even in a static condition, community dynamics are often difficult to predict due to highly nonlinear interspecies interactions. Understanding the fundamental principles of microbial interactions is therefore key for predicting and harnessing community function and properties. As extensively reviewed previously, mathematical models and computational methods that can predictively link interactions to community behaviors are indispensable tools for achieving this goal [1].

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Impacts Of Cover Crops On Soil Physical Properties: Field Capacity, Permanent Wilting Point, Soil-Water Holding Capacity, Bulk Density, Hydraulic Conductivity, And Infiltration, Suat Irmak, Vivek Sharma, Ali T. Mohammed, Koffi Djaman Jan 2018

Impacts Of Cover Crops On Soil Physical Properties: Field Capacity, Permanent Wilting Point, Soil-Water Holding Capacity, Bulk Density, Hydraulic Conductivity, And Infiltration, Suat Irmak, Vivek Sharma, Ali T. Mohammed, Koffi Djaman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Field experiments were carried out to quantify the effects of cover cropping on soil physical properties. Field capacity (FC), permanent wilting point (PWP), soil-water holding capacity (SWHC), bulk density (  b), saturated and unsaturated hydraulic conductivity (Ks and Kus, respectively), and infiltration rates were measured and compared for four land cover treatments [cover crop without seed maize (CC), seed maize followed by cover crop (SCCC), bare soil, and seed maize without cover crop (SC)] in three large-scale production fields (~64 ha each) with silt loam soil in the 2012-2013, 2013-2014, 2014-2015, and 2015-2016 cover crop growing seasons. All production …

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Saw Assisted Domain Wall Motion In Co/Pt Multilayers, Westin Edrington, Uday Singh, Maya Abo Dominguez, James Rehwaldt Alexander, Rabindra Nepal, Shireen Adenwalla Jan 2018

Saw Assisted Domain Wall Motion In Co/Pt Multilayers, Westin Edrington, Uday Singh, Maya Abo Dominguez, James Rehwaldt Alexander, Rabindra Nepal, Shireen Adenwalla

Shireen Adenwalla Papers

The motion of domain walls in thin ferromagnetic films is of both fundamental and technological interest. In particular, the ability to use drivers other than magnetic fields to control the positions of domain walls could be exciting for memory applications. Here, we show that high frequency dynamic strain produced by surface acoustic waves is an efficient driver of magnetic domain walls in ferromagnetic films with perpendicular anisotropy. A standing surface acoustic wave of resonant frequency 96.6MHz increases the domain wall velocities in thin films of [Co/Pt]n by an order of magnitude compared to magnetic fields alone. This effect is highly …

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Sustainable Waste-To-Energy Technologies: Bioelectrochemical Systems, Rami Ziara, Bruce Dvorak, Jeyamkondan Subbiah Jan 2018

Sustainable Waste-To-Energy Technologies: Bioelectrochemical Systems, Rami Ziara, Bruce Dvorak, Jeyamkondan Subbiah

Department of Civil and Environmental Engineering: Faculty Publications

The food industry produces a large amount of waste and wastewater, of which most of the constituents are carbohydrates, proteins, lipids, and organic fibers. Therefore food wastes are highly biodegradable and energy rich. Bioelectrochemical systems (BESs) are systems that use microorganisms to biochemically catalyze complex substrates into useful energy products, in which the catalytic reactions take place on electrodes. Microbial fuel cells (MFCs) are a type of bioelectrochemical systems that oxidize substrates and generate electric current. Microbial electrolysis cells (MECs) are another type of bioelectrochemical systems that use an external power source to catalyze the substrate into by-products such as …

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Signal Timing Optimization For Corridors With Multiple Highway-Rail Grade Crossings Using Genetic Algorithm, Yifeng Chen, Laurence Rilett Jan 2018

Signal Timing Optimization For Corridors With Multiple Highway-Rail Grade Crossings Using Genetic Algorithm, Yifeng Chen, Laurence Rilett

Department of Civil and Environmental Engineering: Faculty Publications

Safety and efficiency are two critical issues at highway-rail grade crossings (HRGCs) and their nearby intersections. Standard traffic signal optimization programs are not designed to work on roadway networks that contain multiple HRGCs, because their underlying assumption is that the roadway traffic is in a steady-state.During a train event, steady-state conditions do not occur.This is particularly true for corridors that experience high train traffic (e.g., over 2 trains per hour). In this situation, the non-steadystate conditions predominate. This paper develops a simulation-based methodology for optimizing traffic signal timing plan on corridors of this kind.The primary goal is to maximize safety, …

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Investigation Of Rapid Remote Sensing Techniques For Forensic Wind Analyses, Yijun Liao, Richard L. Wood, Mohammad Ebrahim Mohammadi, Peter J. Hughes, J. Arn Womble Jan 2018

Investigation Of Rapid Remote Sensing Techniques For Forensic Wind Analyses, Yijun Liao, Richard L. Wood, Mohammad Ebrahim Mohammadi, Peter J. Hughes, J. Arn Womble

Department of Civil and Environmental Engineering: Faculty Publications

Perishable damage data resulting from severe windstorms require efficient and rapid field collection techniques. Such datasets permit forensic damage investigations and characterization of civil infrastructure. Ultimately, observed structural damage serves as a proxy approach to estimate wind speeds for storms that include hurricanes, tornadoes, straight-line winds, etc. One of the more common methods to collect, preserve, and reconstruct three-dimensional damage scenes is the use of an unmanned aerial system (UAS), commonly known as a drone. Onboard photographic payloads permit scene reconstruction via structure-from-motion; however, such approaches often require direct site access and survey points for accurate results, which limit its …

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Behavior Of Cold-Formed Steel Metal Industrial Buildings, Adrianna M. Early, Mohammad Ebrahim Mohammadi, Richard L. Wood, Kara D. Peterma Jan 2018

Behavior Of Cold-Formed Steel Metal Industrial Buildings, Adrianna M. Early, Mohammad Ebrahim Mohammadi, Richard L. Wood, Kara D. Peterma

Department of Civil and Environmental Engineering: Faculty Publications

This paper presents research focused on understanding the observed behavior of cold-formed steel (CFS) metal buildings during Hurricane Harvey, which made landfall Friday, August 25, 2017 between Port Aransas and Port O’Connor, Texas. Through the Geotechnical Extreme Event Reconnaissance (GEER) association (funded by the National Science Foundation) a team of structural engineers and researchers performed rapid and detailed assessments of structural damage caused by the hurricane. The National Science Foundation gathered photographs, damage assessments sheets, and three-dimensional laser point cloud data of severely damaged cold-formed steel industrial buildings. The Port Aransas County Airport experienced severe damage to several cold-formed steel …

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Post-Earthquake Structural Damage Assessment Through Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood Jan 2018

Post-Earthquake Structural Damage Assessment Through Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood

Department of Civil and Environmental Engineering: Faculty Publications

Structural damage assessment following an extreme event can provide valuable information and insight into unanticipated damage and failure modes to improve design philosophies and design codes as well as reduce vulnerability. Oftentimes, structural engineers create finite element models (FEM) of the structure in which numerous model parameters require calibration to simulate the current state. This information may include structural plan details (geometry), material characteristics (strength and stiffness parameters), as well as observed damage patterns (cracks, spalling, etc.). Ground-based lidar (GBL) scans and Structure-from-Motion (SfM) can rapidly capture dimensionally accurate point clouds of the structure or facility of interest. Furthermore, point …

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