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2016

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Articles 421 - 450 of 450

Full-Text Articles in Other Civil and Environmental Engineering

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, …

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Long-Term Patterns Of Air Temperatures, Daily Temperature Range, Precipitation, Grass-Reference Evapotranspiration And Aridity Index In The Usa Great Plains: Part Ii. Temporal Trends, Meetpal S. Kukal, Suat Irmak Jan 2016

Long-Term Patterns Of Air Temperatures, Daily Temperature Range, Precipitation, Grass-Reference Evapotranspiration And Aridity Index In The Usa Great Plains: Part Ii. Temporal Trends, Meetpal S. Kukal, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Detection of long-term changes in climate variables over large spatial scales is a very important prerequisite to the development of effective mitigation and adaption measures for the future potential climate change and for developing strategies for future hydrologic balance analyses under changing climate. Moreover, there is a need for effective approaches of providing information about these changes to decision makers, water managers and stakeholders to aid in efficient implementation of the developed strategies. This study involves computation, mapping and analyses of long-term (1968-2013) county-specific trends in annual, growing-season (1st May- 30th Sept.) and monthly air temperatures [(maximum (Tmax), …

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Long-Term Patterns Of Air Temperatures, Daily Temperature Range, Precipitation, Grass-Reference Evapotranspiration And Aridity Index In The Usa Great Plains: Part I. Spatial Trends, Meetpal S. Kukal, Suat Irmak Jan 2016

Long-Term Patterns Of Air Temperatures, Daily Temperature Range, Precipitation, Grass-Reference Evapotranspiration And Aridity Index In The Usa Great Plains: Part I. Spatial Trends, Meetpal S. Kukal, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Due to their substantial spatio-temporal behavior, long-term quantification and analyses of important hydrological variables are essential for practical applications in water resources planning, evaluating the water use of agricultural crop production and quantifying crop evapotranspiration patterns and irrigation management vs. hydrologic balance relationships. Observed data at over 800 sites across the Great Plains of USA, comprising of 9 states and 2,307,410 km2 of surface area, which is about 30% of the terrestrial area of the USA, were used to quantify and map large-scale and long-term (1968-2013) spatial trends of air temperatures, daily temperature range (DTR), precipitation, grass-reference evapotranspiration (ET …

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Calibration Procedure For Fuel Flow Meters At The Nebraska Tractor Test Lab, Michael F. Kocher, Matthew T. Wold, Roger M. Hoy, Austin Lammers, Erin E. Blankenship Jan 2016

Calibration Procedure For Fuel Flow Meters At The Nebraska Tractor Test Lab, Michael F. Kocher, Matthew T. Wold, Roger M. Hoy, Austin Lammers, Erin E. Blankenship

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Reports in the literature indicated several factors that can influence the accuracy of Coriolis Effect mass flow meters. A Coriolis Effect mass flow meter is used to verify tractor manufacturer’s fuel consumption claims at the Nebraska Tractor Test Laboratory (NTTL). The accuracy requirement placed on the flow meter by the Organization for Economic Co-operation and Development (OECD) in the Code 2 tractor performance test procedure is not clear, but in the most conservative interpretation is ±0.5% of each flow rate measured. Results showed a dynamic weighing calibration method was not accurate enough to obtain a calibration of the flow meter …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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Protein-Targeted Corona Phase Molecular Recognition, Gili Bisker, Juyao Dong, Hoyoung D. Park, Nicole M. Iverson, Jiyoung Ahn, Justin T. Nelson, Markita P. Landry, Sebastian Kruss, Michael S. Strano Jan 2016

Protein-Targeted Corona Phase Molecular Recognition, Gili Bisker, Juyao Dong, Hoyoung D. Park, Nicole M. Iverson, Jiyoung Ahn, Justin T. Nelson, Markita P. Landry, Sebastian Kruss, Michael S. Strano

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated …

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Preliminary Investigation Into The Rate Of Carbonation Of Concrete Blocks Under Normal Production Yard Conditions, Aimee Byrne, Eanna Nolan Jan 2016

Preliminary Investigation Into The Rate Of Carbonation Of Concrete Blocks Under Normal Production Yard Conditions, Aimee Byrne, Eanna Nolan

Conference papers

The release of CO2 from calcination during the manufacture of cement can be partially or fully offset by the CO2 it naturally absorbs during its lifetime. This paper reports results from a preliminary investigation into the rate of carbonation in concrete blocks stacked in a production yard over a period of 6 months. The blocks were stacked in a normal manner under natural exposure conditions. Carbonation progress was determined by splitting the blocks and spraying the freshly exposed surface with a phenolphthalein solution at intervals over the test period. It was found that the rate of the carbonation front progression …

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Designing A Permeable Reactive Barrier For The Remediation Of Copper Contaminated Groundwater., Christopher Walkons Jan 2016

Designing A Permeable Reactive Barrier For The Remediation Of Copper Contaminated Groundwater., Christopher Walkons

Dissertations, Master's Theses and Master's Reports

This project details the design of a sorption based pilot-scale permeable reactive barrier (PRB) for the removal of copper from groundwater. The reactive material for the barrier is the residual of coagulants used in drinking water treatment operations. Physical and chemical properties of these water treatment residuals (WTR) have been studied to optimize PRB design. Batch reactor tests have shown that equilibrium sorption of copper can be fit to a Langmuir type isotherm. Kinetic and column experiments have been conducted to understand the significance of chemical and physical mass transfer limitations. A leaching test indicated the concentrations of hazardous elements …

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A Sustainability-Based Project Selection Algorithm: Socio-Technical-Economic Project Selection (Steps) Algorithm, Bharathi Bhattu Jan 2016

A Sustainability-Based Project Selection Algorithm: Socio-Technical-Economic Project Selection (Steps) Algorithm, Bharathi Bhattu

Dissertations, Master's Theses and Master's Reports

Multi-dimensional aspects play a vital role in the task of project-decision making. Environmental effects are to be considered in addition to other technical and non-technical aspects in order to avoid undue environmental damage. This current work introduces a new decision-making algorithm (Socio-Technical-Economic Project Selection or STEPS) that is demonstrated with the use of RCA (recycled concrete aggregate) as riprap for slope stabilization and erosion control which leaches chemical arsenic when in contact with water. Arsenic has long been recognized for its lethal properties. The main intention of introducing this new algorithm is to use sustainability concepts of social, technical, and …

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Potential Wave Impacts On Shorelines In Intertidal Waterways, Collin Ries Jan 2016

Potential Wave Impacts On Shorelines In Intertidal Waterways, Collin Ries

UNF Graduate Theses and Dissertations

Coastal erosion is caused by a deficit in the sediment balance along coastal shorelines. Within the intertidal waterway of Jacksonville, Florida, the primary processes acting on the shoreline are tidal currents and waves generated by winds and passing vessels. This study focuses on the analysis of vessel-generated waves and their possible effects on different shoreline types. The experiment conducted herein examines variations in turbidity related to passing boats at a specifically selected site location, at which different tidal stages expose three different shoreline types, a non-vegetated scarp, a vegetated scarp and a vegetated area with no scarp in the breaking …

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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 …

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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 …

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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., …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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, …

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Cement Based Batteries And Their Potential For Use In Low Power Operations, Aimee Byrne, Niall Holmes, Brian Norton Jan 2016

Cement Based Batteries And Their Potential For Use In Low Power Operations, Aimee Byrne, Niall Holmes, Brian Norton

Articles

This paper presents the development of an innovative cement-electrolyte battery for low power operations such as cathodic protection of reinforced concrete. A battery design was refined by altering different constituents and examining the open circuit voltage, resistor loaded current and lifespan. The final design consisted of a copper plate cathode, aluminium plate anode, and a cement electrolyte which included additives of carbon black, plasticiser, Alum salt and Epsom salt. A relationship between age, temperature and hydration of the cell and the current it produced was determined. It was found that sealing the battery using varnish increased the moisture retention and …

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The Influence Of Sea-Level Rise On Salinity In The Lower St. Johns River And The Associated Physics, Teddy Mulamba Jan 2016

The Influence Of Sea-Level Rise On Salinity In The Lower St. Johns River And The Associated Physics, Teddy Mulamba

UNF Graduate Theses and Dissertations

The lower St Johns River is a low-gradient coastal river with tidal hydrodynamics that remain active from the Atlantic Ocean through to the upstream end of Lake George (river km 200). Salinity in the lower St Johns River is spatially and temporally variable, whereby the salinity distribution is driven primarily by the combination of ocean processes of tides and storm surges and hydrological processes of watershed runoff. This study examines the probability distributions and modes of behavior of salinity for present-day conditions using data, numerical modeling and eigen-analysis. The hypothesis is that long-term changes (decadal scale) in the ocean processes …

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The Next Billion: Lessons In Off-Grid Electricity Development From The Global South, Peter Mcdonough Jan 2016

The Next Billion: Lessons In Off-Grid Electricity Development From The Global South, Peter Mcdonough

Graduate Student Theses, Dissertations, & Professional Papers

Today about a third of the world’s population has no access to electricity, and another third has only limited access. Driven by the push for development on one hand and the reality of climate change on the other, a combination of for-profit companies, NGOs, missions, and aid organizations is looking for the silver bullet to sustainable electricity development. In order to understand the challenges facing off-grid electricity projects I used recent literature in the form of peer-reviewed journals, agency reports, news articles, and technical documents; stakeholder interviews; and on-site observations in selected case studies in Nepal, India, and Tanzania. In …

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