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2016

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Articles 691 - 720 of 726

Full-Text Articles in Environmental Engineering

Extreme Hydrological Changes In The Southwestern Us Drive Reductions In Water Supply To Southern California By Mid Century, Brianna R. Pagan, Moetasim Ashfaq, Deeksha Rastogi, Donald R. Kendall, Shih-Chieh Kao, Bibi S. Naz, Rui Mei, Jeremy S. Pal Jan 2016

Extreme Hydrological Changes In The Southwestern Us Drive Reductions In Water Supply To Southern California By Mid Century, Brianna R. Pagan, Moetasim Ashfaq, Deeksha Rastogi, Donald R. Kendall, Shih-Chieh Kao, Bibi S. Naz, Rui Mei, Jeremy S. Pal

Civil and Environmental Engineering Faculty Works

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive artificial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble modeling approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly …


Decision Making Of Environmental Engineers On Project Selection, Millicent Amanda Davis Jan 2016

Decision Making Of Environmental Engineers On Project Selection, Millicent Amanda Davis

Walden Dissertations and Doctoral Studies

Some environmental engineers do not understand how to perceive profitable opportunities in redeveloping the large number of contaminated brownfield sites in New Jersey. The purpose of this qualitative exploratory case study was to find effective decision-making strategies that help environmental engineers acquire profitable environmental redevelopment projects. The target population consisted of 4 environmental engineers in an environmental organization in Camden County, New Jersey who possessed proven decision-making strategies that helped them acquire profitable environmental redevelopment projects in the past 5 years. The conceptual framework for this study was the multiple criteria decision method (MCDM). Semistructured interviews were conducted with the …


A Characterization Of The Water Quality Conditions And Pollutant Loads In Surface Waters Near The Northeast Ohio Regional Sewer District’S Combined Sewer System In Cleveland, Ohio, Nathan Zgnilec Jan 2016

A Characterization Of The Water Quality Conditions And Pollutant Loads In Surface Waters Near The Northeast Ohio Regional Sewer District’S Combined Sewer System In Cleveland, Ohio, Nathan Zgnilec

Dissertations, Master's Theses and Master's Reports

The Northeast Ohio Regional Sewer District (NEORSD, Cleveland, OH) serves over one million citizens through the operation of three waste water treatment plants. NEORSD provides this service through combined and separated sewer systems, which, during rainfall events, are known to deliver large volumes of untreated wastewater containing high concentrations of Escherichia coli (E.coli), ammonia nitrogen, and phosphorus. NEORSD is currently investing $3 billion over the next 25 years to mitigate its combined sewer overflows and plans to allocate additional funds to improve remaining pollutant sources related to its system, e.g. separated sewers. A suite of PC-SWMM pollutant loading models have …


Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl Jan 2016

Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl

Dissertations, Master's Theses and Master's Reports

The aim of this study was to validate and apply a lake model for predicting the susceptibility of small inland lakes in Michigan to changes in thermal regime and increased cyanobacteria growth as a result of future climate conditions. The Freshwater Lake Model was selected, tested for sensitivity to various inputs, and validated through comparison to observed conditions. The sensitivity analysis showed that the lake model was most sensitive to solar radiation, air temperature, and air humidity. Comparison of predicted climate data with observed conditions revealed highly variable climate model error. The lake model validation was conducted using 10 lakes …


Polychlorinated Biphenyl Compound And Metal Contamination And Remediation In Torch Lake, Houghton County, Mi, Ankita Mandelia Jan 2016

Polychlorinated Biphenyl Compound And Metal Contamination And Remediation In Torch Lake, Houghton County, Mi, Ankita Mandelia

Dissertations, Master's Theses and Master's Reports

Torch Lake was subject to approximately 100 years of industrial pollution due to the dumping of waste associated with copper mining in the Keweenaw Peninsula, which lasted from approximately the 1860s through the 1960s. It is well-known that this waste included copper-containing mine tailings. What was less understood are the impacts of polychlorinated biphenyls (PCBs) and heavy metals besides copper on the lake system.

The objectives of this thesis are to summarize the status of contamination and remediation activities in Torch Lake and to estimate the magnitude of potential sources of PCBs to Torch Lake. First, a brief overview of …


Early Life History Of Three Pelagic-Spawning Minnows Macrhybopsis Spp. In The Lower Missouri River, T. A. Starks, M. L. Miller, J. M. Long Jan 2016

Early Life History Of Three Pelagic-Spawning Minnows Macrhybopsis Spp. In The Lower Missouri River, T. A. Starks, M. L. Miller, J. M. Long

United States Army Corps of Engineers, Omaha District

Life-history characteristics of age-0 sturgeon chub Macrhybopsis gelida, shoal chub Macrhybopsis hyostoma and sicklefin chub Macrhybopsis meeki were compared using several methods. All Macrhybopsis species consumed mostly midge pupae, but M. meeki had the most general diet (Levins’ index, B=0⋅22) compared with M. hyostoma (B=0⋅02) and M. gelida (B=0⋅09). Morisita’s diet overlap index among species pairs ranged from 0⋅62 to 0⋅97 and was highest between M. hyostoma and M. gelida. Daily ages estimated from lapilli otoliths for each species ranged from 15 to 43 days for M. gelida, 19 to 44 for …


Temporal Dynamics Of Maize Plant Growth, Water Use, And Leaf Water Content Using Automated High Throughput Rgb And Hyperspectral Imaging, Yufeng Ge, Geng Bai, Vincent Stoerger, James C. Schnable Jan 2016

Temporal Dynamics Of Maize Plant Growth, Water Use, And Leaf Water Content Using Automated High Throughput Rgb And Hyperspectral Imaging, Yufeng Ge, Geng Bai, Vincent Stoerger, James C. Schnable

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Automated collection of large scale plant phenotype datasets using high throughput imaging systems has the potential to alleviate current bottlenecks in data-driven plant breeding and crop improvement. In this study, we demonstrate the characterization of temporal dynamics of plant growth and water use, and leaf water content of two maize genotypes under two different water treatments. RGB (Red Green Blue) images are processed to estimate projected plant area, which are correlated with destructively measured plant shoot fresh weight (FW), dry weight (DW) and leaf area. Estimated plant FW and DW, along with pot weights, are used to derive daily plant …


Analytical Solution For Speed To Achieve A Desired Operating Point For A Given Fan Or Pump, Michael F. Kocher, Jeyamkondan Subbiah Jan 2016

Analytical Solution For Speed To Achieve A Desired Operating Point For A Given Fan Or Pump, Michael F. Kocher, Jeyamkondan Subbiah

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Affinity Laws for fans (and pumps) provide a way of determining new fan or pump speed given fan or pump performance curve data and a desired operating point (combination of flow rate and pressure) that does not fall on the curve. However, the affinity law calculations require using a point on the curve (hereafter referred to as the “basic point”) to determine the new speed. Most references regarding the Affinity Laws do not give a clear description of the method for determining the “basic point”, and improper selection of this point can affect the results considerably. This article describes …


In-Field Fuel Use And Load States Of Agricultural Field Machinery, Santosh Pitla, Joe D. Luck, Jared Werner, Nannan Lin, Scott A. Shearer Jan 2016

In-Field Fuel Use And Load States Of Agricultural Field Machinery, Santosh Pitla, Joe D. Luck, Jared Werner, Nannan Lin, Scott A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The ability to define in-field tractor load states offers the potential to better specify and characterize fuel consumption rate for various field operations. For the same field operation, the tractor experiences diverse load demands and corresponding fuel use rates as it maneuvers through straight passes, turns, suspended operation for adjustments, repair and maintenance, and biomass or other material transfer operations. It is challenging to determine the actual fuel rate and load states of agricultural machinery using force prediction models, and hence, some form of in-field data acquisition capability is required. Controller Area Networks (CAN) available on the current model tractors …


Inter-Row Robot Navigation Using 1d Ranging Sensors, Tyler A. Troyer, Santosh Pitla, Ethan Nutter Jan 2016

Inter-Row Robot Navigation Using 1d Ranging Sensors, Tyler A. Troyer, Santosh Pitla, Ethan Nutter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In this paper a fuzzy logic navigation controller for an inter-row agricultural robot is developed and evaluated in laboratory settings. The controller receives input from one-dimensional (1D) ranging sensors on the robotic platform, and operated on ten fuzzy rules for basic row-following behavior. The control system was implemented on basic hardware for proof of concept and operated on a commonly available microcontroller development platform and open source software libraries. The robot platform used for experimentation was a small tracked vehicle with differential steering control. Fuzzy inferencing and defuzzification, step response and cross track error were obtained from the test conducted …


Tractor Hydraulic Power Data Acquisition System, J. B.W. Roeber, Santosh Pitla, Michael F. Kocher, Joe D. Luck, Roger M. Hoy Jan 2016

Tractor Hydraulic Power Data Acquisition System, J. B.W. Roeber, Santosh Pitla, Michael F. Kocher, Joe D. Luck, Roger M. Hoy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tractor hydraulic power is used on a wide range of agricultural implements; however, the availability of operational hydraulic data at points other than full engine throttle position is limited. Operators could utilize this hydraulic data to maximize field efficiency and minimize machinery costs when determining suitable machinery for field operations. A field usable hydraulic test apparatus capable of measuring tractor hydraulic pressure and flow rate data was developed. The goal of this study was to determine if a hydraulic flow and pressure measurement device could be installed on the rear of a tractor to provide implement hydraulic power consumption at …


Quantifying The Fate Of Agricultural Nitrogen In An Unconfined Aquifer: Stream-Based Observations At Three Measurement Scales, Troy E. Gilmore, David P. Genereux, D. Kip Solomon, John E. Solder, Briant A. Kimball, Helena Mitasova, Francois Birgand Jan 2016

Quantifying The Fate Of Agricultural Nitrogen In An Unconfined Aquifer: Stream-Based Observations At Three Measurement Scales, Troy E. Gilmore, David P. Genereux, D. Kip Solomon, John E. Solder, Briant A. Kimball, Helena Mitasova, Francois Birgand

Department of Agricultural and Biological Systems Engineering: Faculty Publications

We compared three stream-based sampling methods to study the fate of nitrate in groundwater in a coastal plain watershed: point measurements beneath the streambed, seepage blankets (novel seepage-meter design), and reach mass-balance. The methods gave similar mean groundwater seepage rates into the stream (0.3–0.6 m/d) during two 3–4 day field campaigns despite an order of magnitude difference in stream discharge between the campaigns. At low flow, estimates of flowweighted mean nitrate concentrations in groundwater discharge ([NO-3 ]FWM) and nitrate flux from groundwater to the stream decreased with increasing degree of channel influence and measurement scale, i.e., …


Groundwater Transit Time Distribution And Mean From Streambed Sampling In An Agricultural Coastal Plain Watershed, North Carolina, Usa, Troy E. Gilmore, David P. Genereux, D. Kip Solomon, John E. Solder Jan 2016

Groundwater Transit Time Distribution And Mean From Streambed Sampling In An Agricultural Coastal Plain Watershed, North Carolina, Usa, Troy E. Gilmore, David P. Genereux, D. Kip Solomon, John E. Solder

Department of Agricultural and Biological Systems Engineering: Faculty Publications

We measured groundwater apparent age (s) and seepage rate (v) in a sandy streambed using point-scale sampling and seepage blankets (a novel seepage meter). We found very similar MTT estimates from streambed point sampling in a 58 m reach (29 years) and a 2.5 km reach (31 years). The TTD for groundwater discharging to the stream was best fit by a gamma distribution model and was very similar for streambed point sampling in both reaches. Between adjacent point-scale and seepage blanket samples, water from the seepage blankets was generally younger, largely because blanket samples contained a fraction of ‘‘young’’ stream …


Comparing Various Hardware/Software Solutions And Conversion Methods For Controller Area Network (Can) Bus Data Collection, Samuel E. Marx, Joe D. Luck, Santosh Pitla, Roger M. Hoy Jan 2016

Comparing Various Hardware/Software Solutions And Conversion Methods For Controller Area Network (Can) Bus Data Collection, Samuel E. Marx, Joe D. Luck, Santosh Pitla, Roger M. Hoy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Various hardware and software solutions exist for collecting Controller Area Network (CAN) bus data. Digital data accuracy could vary based upon different data logging methods (e.g., hardware/software timing, processor timing, etc.). CAN bus data were collected from agricultural tractors using multiple data acquisition solutions to quantify differences among collection methods and demonstrate potential data accumulation rates. Two types of data were observed for this study. The first, CAN bus frame data, represents data collected for each line of hex data sent from an ECU. One issue with frame data is the resulting large file sizes, therefore a second logging format …


Removal Of Cattle Manure Constituents In Runoff From No-Till Cropland As Affected By Setback Distance, John E. Gilley, Aaron J. Sindelar, Brian L. Woodbury Jan 2016

Removal Of Cattle Manure Constituents In Runoff From No-Till Cropland As Affected By Setback Distance, John E. Gilley, Aaron J. Sindelar, Brian L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Vegetative filter strips located at the bottom of a hillslope have been shown to substantially reduce nutrients and sediment in runoff. Cropland areas could serve a similar function. However, little scientifically derived information is available to help identify the setback distances required to effectively reduce the transport of contaminants in runoff. The objective of this study was to determine the effects of setback distance and runoff rate on the concentrations and mass transport rates of selected constituents following land application of beef cattle manure to a no-till cropland area. The study site had a residue cover of 8.84 Mg ha-1 …


Impact Of Scale/Resolution On Evapotranspiration From Landsat And Modis Images, Vivek Sharma, Ayse Kilic, Suat Irmak Jan 2016

Impact Of Scale/Resolution On Evapotranspiration From Landsat And Modis Images, Vivek Sharma, Ayse Kilic, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Understanding the role of landscape heterogeneity and its influence on the scaling behavior of surface fluxes as observed by satellite sensors with different spatial resolutions is a critical need to investigate. In this study, the effects of pixel scales on ETc estimation and other parameters that are used to calculate ETc were investigated over different vegetation surfaces in south central Nebraska, USA. Surface Energy Balance System (SEBS) was used to estimate spatially distributed ETc by combining ground-based meteorological data for Landsat and MODIS imagery. The estimated surface energy fluxes were compared and validated to the measured Bowen Ratio Energy Balance …


Removal Of Cattle Manure Constituents In Runoff From No-Till Cropland As Affected By Setback Distance, John E. Gilley, Aaron J. Sindelar, Bryan L. Woodbury Jan 2016

Removal Of Cattle Manure Constituents In Runoff From No-Till Cropland As Affected By Setback Distance, John E. Gilley, Aaron J. Sindelar, Bryan L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Vegetative filter strips located at the bottom of a hillslope have been shown to substantially reduce nutrients and sediment in runoff. Cropland areas could serve a similar function. However, little scientifically derived information is available to help identify the setback distances required to effectively reduce the transport of contaminants in runoff. The objective of this study was to determine the effects of setback distance and runoff rate on the concentrations and mass transport rates of selected constituents following land application of beef cattle manure to a no-till cropland area. The study site had a residue cover of 8.84 Mg ha …


262. Direct Measure Of Cervical Interbody Forces In Vivo: Load Reversal After Plating, Eric H. Ledet, Josh Peterson, Rebecca A. Wachs, Mary Beth M. Grabowsky, Joseph C. Glennon, Darryl J. Dirisio Jan 2016

262. Direct Measure Of Cervical Interbody Forces In Vivo: Load Reversal After Plating, Eric H. Ledet, Josh Peterson, Rebecca A. Wachs, Mary Beth M. Grabowsky, Joseph C. Glennon, Darryl J. Dirisio

Department of Agricultural and Biological Systems Engineering: Faculty Publications

BACKGROUND CONTEXT: Biomechanics play an important role in spine fusion, but the in vivo biomechanics of the cervical spine are not well characterized and the in vivo biomechanics after spinal arthrodesis have never been studied. Load sharing facilitates fusion, but overloading of interbody implants can lead to subsidence and failure. In vitro studies have demonstrated that anterior plating significantly alters mechanical loading in the cervical spine. The instantaneous axis of rotation is shifted anteriorly and loading is reversed relative to an uninstrumented spine; the interbody space is compressed during extension and unloaded during flexion. However, this has never been tested …


Moisture Insensitive Prediction Of Soil Properties From Vnir Reflectance Spectra Based On External Parameter Orthogonalization, Nuwan K. Wijewardane, Yufeng Ge, Cristine L.S. Morgan Jan 2016

Moisture Insensitive Prediction Of Soil Properties From Vnir Reflectance Spectra Based On External Parameter Orthogonalization, Nuwan K. Wijewardane, Yufeng Ge, Cristine L.S. Morgan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Moisture is the single most important factor that affects soil reflectance spectra, particularly for field applications. Interest in using soil VNIR spectral libraries, which are commonly based on dry ground soils, to predict soils in the intact field-moist condition (in situ VNIR) is growing. External parameter orthogonalization (EPO) has been proposed as a useful method that links dry ground VNIR models to field moist scans. The goal of this study is to test EPO on a wider set of soil properties and four different modeling techniques, namely, Partial Least Squares Regression (PLS), Artificial Neural Network (ANN), Random Forest (RF), and …


Neural Encoding Of Saltatory Pneumotactile Velocity In Human Glabrous Hand, Hyuntaek Oh, Rebecca Custead, Yingying Wang, Steven M. Barlow Jan 2016

Neural Encoding Of Saltatory Pneumotactile Velocity In Human Glabrous Hand, Hyuntaek Oh, Rebecca Custead, Yingying Wang, Steven M. Barlow

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Neurons in the somatosensory cortex are exquisitely sensitive to mechanical stimulation of the skin surface. The location, velocity, direction, and adaptation of tactile stimuli on the skin's surface are discriminable features of somatosensory processing, however the representation and processing of dynamic tactile arrays in the human somatosensory cortex are poorly understood. The principal aim of this study was to map the relation between dynamic saltatory pneumatic stimuli at discrete traverse velocities on the glabrous hand and the resultant pattern of evoked BOLD response in the human brain. Moreover, we hypothesized that the hand representation in contralateral Brodmann Area (BA) 3b …


Analyses, Calibration And Validation Of Evapotranspirationmodels To Predict Grass-Reference Evapotranspiration In Thesenegal River Delta, Koffi Djaman, Hossein Tabari, Alpha B. Balde, Lamine Diop, Koichi Futakuchi, Suat Irmak Jan 2016

Analyses, Calibration And Validation Of Evapotranspirationmodels To Predict Grass-Reference Evapotranspiration In Thesenegal River Delta, Koffi Djaman, Hossein Tabari, Alpha B. Balde, Lamine Diop, Koichi Futakuchi, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Study region: Grass-reference evapotranspiration estimation by the Penman-Monteithmethod (PM-ETo) requires a number of climate variables which are not always availableat all weather stations. Different alternative ETo equations have been developed and theirutilization for various local climate conditions requires analyses of their accuracy as com-pared to the standardized Penman-Monteith method. There is a significant lack of data andinformation on this topic in the Senegal River Delta (SRD). Study focus: The objective of this study was to evaluate, calibrate and validate six EToequations ((Trabert, Mahringer, Penman1948, Albrecht, Valiantzas1 and Valiantzas2) forthe SRD. Although all six equations showed good agreement with the PM-ETo …


A Multi-Sensor System For High Throughput Field Phenotyping In Soybean And Wheat Breeding, Geng Bai, Yufeng Ge, Waseem Hussain, P. Stephen Baenziger, George L. Graef Jan 2016

A Multi-Sensor System For High Throughput Field Phenotyping In Soybean And Wheat Breeding, Geng Bai, Yufeng Ge, Waseem Hussain, P. Stephen Baenziger, George L. Graef

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Collecting plant phenotypic data with sufficient resolution (in both space and time) and accuracy represents a long standing challenge in plant science research, and has been a major limiting factor for the effective use of genomic data for crop improvement. This is particularly true in plant breeding where collecting large-scale field-based plant phenotypes can be very labor intensive and costly. In this paper we reported a multi-sensor system for high throughput phenotyping in plant breeding. The system comprised five sensor modules (ultrasonic distance sensors, thermal infrared radiometers, NDVI sensors, portable spectrometers, and RGB web cameras) to measure crop canopy traits …


A Multi-Scale Comparison Of Modeled And Observed Seasonal Methane Emissions In Northern Wetlands, Xiyan Xu, William J. Riley, Charles D. Koven, Dave P. Billesbach, Rachel Y.-W. Chang, Roisin Commane, Eugenie S. Euskirchen, Sean Hartery, Yoshinobu Harazono, Hiroki Iwata, Kyle C. Mcdonald, Charles E. Miller, Walter C. Oechel, Benjamin Poulter, Naama Raz-Yaseef, Colm Sweeny, Margaret Torn, Steven C. Wofsy, Zhen Zhang, Donatella Zona Jan 2016

A Multi-Scale Comparison Of Modeled And Observed Seasonal Methane Emissions In Northern Wetlands, Xiyan Xu, William J. Riley, Charles D. Koven, Dave P. Billesbach, Rachel Y.-W. Chang, Roisin Commane, Eugenie S. Euskirchen, Sean Hartery, Yoshinobu Harazono, Hiroki Iwata, Kyle C. Mcdonald, Charles E. Miller, Walter C. Oechel, Benjamin Poulter, Naama Raz-Yaseef, Colm Sweeny, Margaret Torn, Steven C. Wofsy, Zhen Zhang, Donatella Zona

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wetlands are the largest global natural methane (CH4) source, and emissions between 50 and 70° N latitude contribute 10–30% to this source. Predictive capability of land models for northern wetland CH4 emissions is still low due to limited site measurements, strong spatial and temporal variability in emissions, and complex hydrological and biogeochemical dynamics. To explore this issue, we compare wetland CH4 emission predictions from the Community Land Model 4.5 (CLM4.5-BGC) with siteto regional-scale observations. A comparison of the CH4 fluxes with eddy flux data highlighted needed changes to the model’s estimate of aerenchyma area, which …


Direct And Indirect Effects Of Climatic Variations On The Interannual Variability In Net Ecosystem Exchange Across Terrestrial Ecosystems, Junjiong Shao, Xuhui Zhou, Yiqi Luo, Bo Li, Mika Aurela, David Billesbach, Peter D. Blanken, Rosvel Bracho, Jiquan Chen, Marc Fischer, Yuling Fu, Lianhong Gu, Shijie Han, Yongtao He, Thomas Kolb, Yingnian Li, Zoltan Nagy, Shuli Niu, Walter C. Oechel, Krisztina Pinter, Peili Shi, Andrew Suyker, Margaret Torn, Andrej Varlagin, Huimin Wang, Junhua Yan, Guirui Yu, Junhui Zhang Jan 2016

Direct And Indirect Effects Of Climatic Variations On The Interannual Variability In Net Ecosystem Exchange Across Terrestrial Ecosystems, Junjiong Shao, Xuhui Zhou, Yiqi Luo, Bo Li, Mika Aurela, David Billesbach, Peter D. Blanken, Rosvel Bracho, Jiquan Chen, Marc Fischer, Yuling Fu, Lianhong Gu, Shijie Han, Yongtao He, Thomas Kolb, Yingnian Li, Zoltan Nagy, Shuli Niu, Walter C. Oechel, Krisztina Pinter, Peili Shi, Andrew Suyker, Margaret Torn, Andrej Varlagin, Huimin Wang, Junhua Yan, Guirui Yu, Junhui Zhang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Climatic variables not only directly affect the interannual variability (IAV) in net ecosystem exchange of CO2 (NEE) but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C) dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor …


Cellulase Immobilization On Superparamagnetic Nanoparticles For Reuse In Cellulosic Biomass Conversion, Qing Song, Yu Mao, Mark Wilkins, Fernando Segato, Rolf Prade Jan 2016

Cellulase Immobilization On Superparamagnetic Nanoparticles For Reuse In Cellulosic Biomass Conversion, Qing Song, Yu Mao, Mark Wilkins, Fernando Segato, Rolf Prade

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Current cellulosic biomass hydrolysis is based on the one-time use of cellulases. Cellulases immobilized on magnetic nanocarriers offer the advantages of magnetic separation and repeated use for continuous hydrolysis. Most immobilization methods focus on only one type of cellulase. Here, we report co-immobilization of two types of cellulases, β-glucosidase A (BglA) and cellobiohydrolase D (CelD), on sub-20 nm superparamagnetic nanoparticles. The nanoparticles demonstrated 100% immobilization efficiency for both BglA and CelD. The total enzyme activities of immobilized BglA and CelD were up to 67.1% and 41.5% of that of the free cellulases, respectively. The immobilized BglA and CelD each retained …


Switchgrass Storage Effects On The Recovery Of Carbohydrates After Liquid Hot Water Pretreatment And Enzymatic Hydrolysis, Noaa Frederick, Mengxing Li, Danielle Julie Carrier, Michael D. Buser, Mark R. Wilkins Jan 2016

Switchgrass Storage Effects On The Recovery Of Carbohydrates After Liquid Hot Water Pretreatment And Enzymatic Hydrolysis, Noaa Frederick, Mengxing Li, Danielle Julie Carrier, Michael D. Buser, Mark R. Wilkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Perennial grasses that would be used for bioenergy and bioproducts production will need to be stored for various periods of time to ensure a continual feedstock supply to a bioprocessing facility. The effects of storage practices on grass composition and the response of grasses to subsequent bioprocesses such as pretreatment and enzymatic hydrolysis needs to be understood to develop the most efficient storage protocols. This study examined the effect of outdoor storage of round switchgrass bales on composition before and after liquid hot water pretreatment (LHW) and enzymatic hydrolysis. This study also examined the effect of washing LHW pretreated biomass …


Ecosystem Evapotranspiration: Challenges In Measurements, Estimates, And Modeling, D.M. Amatya, Sibel Irmak, P. Gowda, G. Sun, J.E. Nettles, K.R. Douglas-Mankin Jan 2016

Ecosystem Evapotranspiration: Challenges In Measurements, Estimates, And Modeling, D.M. Amatya, Sibel Irmak, P. Gowda, G. Sun, J.E. Nettles, K.R. Douglas-Mankin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Evapotranspiration (ET) processes at the leaf to landscape scales in multiple land uses have important con- trols and feedbacks for local, regional, and global climate and water resource systems. Innovative methods, tools, and technologies for improved understanding and quantification of ET and crop water use are critical for adapting more effective management strategies to cope with increasing demand for freshwater resources under global climate change. This article introduces an ASABE Special Collection of 12 articles on ET monitoring and modeling research for multiple land uses and scales. The collection focuses on recent advances in four critical topical areas: (1) reference …


Critical Factors Affecting The Integration Of Biomass Gasification And Syngas Fermentation Technology, Karthikeyan D. Ramachandriya, Dimple K. Kundiyana, Ashokkumar M. Sharma, Ajay Kumar, Hasan K. Atiyeh, Raymond L. Huhnke, Mark R. Wilkins Jan 2016

Critical Factors Affecting The Integration Of Biomass Gasification And Syngas Fermentation Technology, Karthikeyan D. Ramachandriya, Dimple K. Kundiyana, Ashokkumar M. Sharma, Ajay Kumar, Hasan K. Atiyeh, Raymond L. Huhnke, Mark R. Wilkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Gasification-fermentation is a thermochemical-biological platform for the production of fuels and chemicals. Biomass is gasified at high temperatures to make syngas, a gas composed of CO, CO2, H2, N2 and other minor components. Syngas is then fed to anaerobic microorganisms that convert CO, CO2 and H2 to alcohols by fermentation. This platform offers numerous advantages such as flexibility of feedstock and syngas composition and lower operating temperature and pressure compared to other catalytic syngas conversion processes. In comparison to hydrolysis-fermentation, gasification-fermentation has a major advantage of utilizing all organic components of biomass, including lignin, to yield higher fuel production. Furthermore, …


Incorporation Of Globally Available Datasets Into The Roving Cosmic-Ray Neutron Probe Method For Estimating Field-Scale Soil Water Content, William A. Avery, Catherine Finkenbiner, Trenton E. Franz, Tiejun Wang, Anthony L. Nguy-Robertson, Andrew E. Suyker, Timothy J. Arkebauer, Francisco Munoz-Arriola Jan 2016

Incorporation Of Globally Available Datasets Into The Roving Cosmic-Ray Neutron Probe Method For Estimating Field-Scale Soil Water Content, William A. Avery, Catherine Finkenbiner, Trenton E. Franz, Tiejun Wang, Anthony L. Nguy-Robertson, Andrew E. Suyker, Timothy J. Arkebauer, Francisco Munoz-Arriola

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The need for accurate, real-time, reliable, and multi-scale soil water content (SWC) monitoring is critical for a multitude of scientific disciplines trying to understand and predict the Earth’s terrestrial energy, water, and nutrient cycles. One promising technique to help meet this demand is fixed and roving cosmic-ray neutron probes (CRNPs). However, the relationship between observed low-energy neutrons and SWC is affected by local soil and vegetation calibration parameters. This effect may be accounted for by a calibration equation based on local soil type and the amount of vegetation. However, determining the calibration parameters for this equation is labor- and time-intensive, …


Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq Jan 2016

Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq

Theses and Dissertations (Comprehensive)

Numerous studies have been conducted on the removal of inorganic phosphorus (P) from wastewater, but a push towards lower effluent targets necessitates the additional removal of organic phosphorus as well. This study tested the ability of manganese oxide nanoparticles and iron oxide as potential catalysts for conversion of organic P into more readily removable inorganic forms, as well as the role of iron(III) chloride as coagulant to subsequently allow P to be removed by solids/liquid separation. Removals of 99-101% were obtained for model compounds at pH 5-7, 0.05-0.5 M H2O2, and Fe:P molar ratio of 5:1. …