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The Role Of Ca2+ In Central Respiratory Control Neurons Of The Locus Coeruleus: Development Of The Chemosensitive Brake, Ann Nicole Imber

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Chemosensitive LC neurons increase their firing rate in response to increased CO₂ (hypercapnia) in part via inhibition of K⁺ channels. This increase gets smaller during the first two postnatal weeks (neonatal rats aged P3-P16). Alterations of this "accelerating" pathway may account for the developmental changes in the magnitude of the chemosensitive response in LC neurons. Alternatively, Ca²⁺ and Ca²⁺ channels may play a role in the response to hypercapnia, but little is known about the role of Ca²⁺ in central chemosensitivity. Whole cell patch clamp and fluorescence imaging microscopy were used to study a different …

Nanostructured Columnar Thin Films Using Oblique Angle Deposition: Growth, Sers Characterization And Lithographic Processing, Piyush J. Shah

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Oblique angle physical vapor deposition technique has led to the evolution of new class of nanostructured thin films. These films posses' novel anisotropic electrical, magnetic, optical, properties which could be potentially engineered based on the growth conditions and the deposition parameters. The technique is based on the atomistic level self-shadowing principle. In the oblique angle deposition (OAD) technique, the substrate is held at an oblique angle with respect to the incoming vapor flux. As the vapor atoms condense and nucleate on the substrate, the shadowed regions behind each site stop receiving the subsequent vapor atoms. Instead, they land on the …

A Mechanism-Based Model To Describe Gabaa Receptor Trafficking And Benzodiazepine Pharmacoresistance During Status Epilepticus, Elaine Alice Merrill

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Status epilepticus (SE) is a perplexing pathology involving a sudden and long disruption of the brain's normal electrical activity. The study of relevant cellular processes has been useful in identifying therapeutic targets. As a result, many novel drugs are being studied which target receptor systems involved in neuronal membrane excitability. Yet, the standard treatment for SE remains benzodiazepines (BZs), a class of GABAA agonist drugs. Unfortunately, the targeted receptors undergo a desensitization mechanism via enhanced endocytosis (receptor trafficking), leading to rapidly reduced BZ efficacy (pharmacoresistance) within minutes of seizure onset. A comprehensive understanding of the complex interplay between the anticonvulsant's …

Quantification Of Multiple Types Of Uncertainty In Physics-Based Simulation, Inseok Park

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In general, more than one simulation model can be created to analyze and design engineering systems. Uncertainty is inevitably involved in selecting a single best approximating model from among a set of simulation models. Uncertainty in model selection (called model-form uncertainty in the present research) cannot be ignored, especially when the differences between the predictions by plausible models are significant. Also, each simulation model involves uncertainty in its input parameters and unknown errors in its predictions of system responses. A methodology is developed to quantify model-form uncertainty using the differences between experimental data measured from an engineering system and model …

The Effect Of Thermal Hydrolysis Pretreatment On The Anaerobic Degradation Of Nonylphenol And Short-Chain Nonylphenol Ethoxylates In Digested Biosolids, Patrick J. Mcnamara, C. A. Wilson, M. T. Wogen, S. N. Murthy, J. T. Novak, Paige J. Novak

Civil and Environmental Engineering Faculty Research and Publications

The presence of micropollutants can be a concern for land application of biosolids. Of particular interest are nonylphenol diethoxylate (NP₂EO), nonylphenol monoethoxylate (NP₁EO), and nonylphenol (NP), collectively referred to as NPE, which accumulate in anaerobically digested biosolids and are subject to regulation based on the environmental risks associated with them. Because biosolids are a valuable nutrient resource, it is essential that we understand how various treatment processes impact the fate of NPE in biosolids. Thermal hydrolysis (TH) coupled with mesophilic anaerobic digestion (MAD) is an advanced digestion process that destroys pathogens in biosolids and increases methane …

Characteristics Of Laterally Vibrating Resonant Microcantilevers In Viscous Liquid Media, Russell Cox, Fabien Josse, Stephen M. Heinrich, Oliver Brand, Isabelle Dufour

Civil and Environmental Engineering Faculty Research and Publications

The characteristics of microcantilevers vibrating laterally in viscous liquid media are investigated and compared to those of similar microcantilevers vibrating in the out-of-plane direction. The hydrodynamic loading on the vibrating beam is first determined using a numerical model. A semi-analytical expression for the hydrodynamic forces in terms of the Reynolds number and the aspect ratio (beam thickness over beam width) is obtained by introducing a correction factor to Stokes’ solution for a vibrating plate of infinite area to account for the effects of the thickness. The results enable the effects of fluid damping and effective fluid mass on the resonant …

Metallic Patterning Using An Atomic Force Microscope Tip And Laser-Induced Liquid Deposition, Carlos Andrés Jarro Sanabria

Theses and Dissertations--Electrical and Computer Engineering

The development of nanoscale patterns has a vast variety of applications going from biology to solid state devices. In this research we present a new direct patterning technique in which laser photoreduction of silver from a liquid is controlled by a scanning atomic force microscope tip. While pursuing the formation of patterns using the plasmonic field enhancement of an electromagnetic wave incident on a metallic Atomic Force Microscope (AFM) tip, our group discovered that contrary to expectations, the tip suppresses, rather than enhances, deposition on the underlying substrate, and this suppression persists in the absence of the tip. Experiments presented …

Analysis Of Π-Phase-Shifted Fiber Bragg Gratings For Ultrasonic Detection, Tongqing Liu, Ming Han

Department of Electrical and Computer Engineering: Faculty Publications

Using numerical simulations, we investigated the responses of the π-phase-shifted fiber Bragg gratings (πFBGs) impinged by pressure ultrasonic waves. The effect of the grating length, grating refractive index modification depth, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the πFBG ultrasonic sensor for ultrasonic waves of different wavelengths was analyzed. The directivity of a πFBG sensor was also studied. Our analysis revealed several unique πFBG response characteristics and will be useful in the design and optimization of fiber-optic ultrasonic sensors that use a πFBG as the sensing element.

Laser Induced Breakdown Spectroscopy Having Enhanced Signal-To-Noise Ratio, Dennis R. Alexander, Troy Anderson, John C. Bruce Iii

Department of Electrical and Computer Engineering: Faculty Publications

A material can be analyzed using short pulses by applying a first pulse and a second pulse to the material in which the second pulse is delayed relative to the first pulse. The first and second pulses are directed toward a material along collinear paths, and the material is ablated using the first pulse to cause particles to be emitted from the surface of the material. The emitted particles are atomized and/or ionized using the second pulse, and the radiation from the atomized and/or ionized particles is analyzed.

Coupled Electromagnetic And Heat Transfer Model For Microwave Heating In Domestic Ovens, Krishnamoorthy Pitchai, Sohan Birla, Jeyamkondan Subbiah, D. D. Jones, Harshanardhan Thippareddi

Department of Food Science and Technology: Faculty Publications

Microwave ovens are used extensively for heating a variety of not-ready-to-eat food products. Non-uniform heating of foods in microwave ovens is a major concern in assuring microbiological safety of such products. The non-uniform heating of foods is attributed by complex interaction of microwaves with foods. To understand this complex interaction, a comprehensive model was developed to solve coupled electromagnetic and heat transfer equations using finite-difference time-domain based commercial software. The simulation parameters, cell size, heating time step, and number of iterations for steady state electromagnetic field were optimized. The model was validated by 30 s heating profile of a cylindrical …

Systems And Synthetic Biology Of The Vessel Wall, Jennifer Frueh, Nataly Maimari, Ying Lui, Zoltan Kis, Vikram Mehta, Negin Pormehr, Calum Grant, Emmanuel Chalkias, Mika Falck-Hansen, Sandra Bovens, Ryan M. Pedrigi, Taka Homma, Gianfillippo Coppola, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is intimately coupled to blood flow by the presence of predilection sites. The coupling is through mechanotransduction of endothelial cells and approximately 2000 gene are associated with this process. This paper describes a new platform to study and identify new signalling pathways in endothelial cells covering an atherosclerotic plaque. The identified networks are synthesized in primary cells to study their reaction to flow. This synthetic approach might lead to new insights and drug targets.

Arterial Wall Mechanics And Clinical Implications After Coronary Stenting: Comparisons Of Three Stent Designs, Linxia Gu, Shijia Zhao, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this work is to quantitatively assess the relationship between the reported restenosis rates and stent induced arterial stress or strain parameters through finite element method. The impact of three stent designs (Palmaz–Schatz stent, Express stent, and Multilink Vision stent) on the arterial stress distributions were characterized. The influences of initial stent deployment location, stent-tissue friction, and plaque properties on the arterial stresses were also investigated. Higher arterial stresses were observed at the proximal end of the plaque. The Multilink–Vision stent induced lesser stress concentrations due to the high stiffness of the Cobalt Chromium material and thinner strut …

In Vivo Demonstration Of Surgical Task Assistance Using Miniature Robots, Jeff A. Hawks, Jacob Kunowski, Stephen R. Platt

Department of Mechanical and Materials Engineering: Faculty Publications

Laparoscopy is beneficial to patients as measured by less painful recovery and an earlier return to functional health compared to conventional open surgery.However, laparoscopy requires the manipulation of long, slender tools from outside the patient’s body. As a result, laparoscopy generally benefits only patients undergoing relatively simple procedures. An innovative approach to laparoscopy uses miniature in vivo robots that fit entirely inside the abdominal cavity. Our previous work demonstrated that a mobile, wireless robot platform can be successfully operated inside the abdominal cavity with different payloads (biopsy, camera, and physiological sensors). We hope that these robots are a step toward …

An Investigation Of Reflective Mulches For Use Over Capillary Mat Systems For Winter-Time Greenhouse Strawberry Production, George E. Meyer, Ellen T. Paparozzi, Elizabeth Walter-Shea, Erin E. Blankenship, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

Photosynthethically active radiation (PAR) is a principle environmental variable used by horticultural specialists, agronomists and ecosystem modelers to characterize the quantity and quality of light conducive to plant growth and development. Spatial distribution of PAR in a greenhouse can be quite variable and diffuse throughout the day time photoperiod, especially at low sun angles in northern regions of the United States. Four colors of reflective plastic mulches (white, red, olive, and black) were evaluated for winter-time strawberry (Fragaria × ananassa Duch.) production based on their reflectance and transmittance properties in a double-polyethylene, plastic-glazed Quonset greenhouse inNebraska. The spectral properties …

A 3-D Computational Fluid Dynamics Model For Forced Air Cooling Of Eggs Placed In Trays, Vikas Kumar, Ai Pheeng Wee, Sohan Birla, Jeyamkondan Subbiah, Harshanardhan Thippareddi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Shell eggs must be cooled quickly after laying for controlling Salmonella Enteritidis (SE) growth. To fulfill a research need identified by Food Safety and Inspection Service (FSIS), a 3-D Computational Fluid Dynamics (CFD) model was developed to predict the temperature of eggs placed on a tray (6 rows × 5 columns) under forced air cooling. The continuity, momentum, and energy equations were solved along with standard k-ε turbulence model using PHOENICS software. The model was validated by conducting experiments in a wind tunnel at various air temperatures (7–11 °C) and velocities (0.3– 0.7 m/s). Root mean square error for predicting …

The Biological Systems Engineering Program In Nebraska 1895-2011, William Splinter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

4. Preface: How Mechanization Has Impacted Food Production THE PIONEERS WHO ESTABLISHED THIS DEPARTMENT 8 Oscar Van Pelt Stout 10 Charles Russ Richards 12 J. Brownlee Davidson 14 Leon W. Chase FORMER FACULTY AND THEIR CONTRIBUTIONS 18 Laurence Froyd Seaton 20 Ivan D.Wood 22 Oscar W. Sjogren 23 Chauncey W. Smith 25 Elmer E. Brackett 27 Claud Kedzie Shedd 29 Ruby M. Loper 31 Lester F. Larsen 33 Lloyd W. Hurlbut 36 Rollin Schnieder 39 Howard D. Wittmuss 41 Deon Axthelm 46 Paul. E. Fischbach 48 Stuart O. Nelson 51 Kenneth von Bargen 56 John R. Davis 58 Robert W. …

Evaluation Of The Impact Of Surface Residue Cover On Single And Dual Crop Coefficient For Estimating Soybean Actual Evapotranspiration, Lameck O. Odhiambo, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Single and dual crop coefficient methods are used in conjunction with grass reference evapotranspiration (ET_o) to estimate actual crop evapotranspiration (ET_c). However, the impact of soil surface residue cover on the accuracy of ET_c estimated with these methods is not well understood. The objective of this study is to evaluate and compare the accuracy of the FAO-56 single crop coefficient (single-K_c) and dual crop coefficient (dual-K_c) methods for estimating soybean [Glycine max (L.) Merr.] ET_c in a partially residue covered field. The study was conducted …

Using Rapid Geomorphic Assessments To Assess Streambank Stability In Oklahoma Ozark Streams, Derek M. Heeren, Aaron R. Mittelstet, Garey A. Fox, Daniel E. Storm, Abdulsahib T. Al-Madhhachi, Taber L. Midgley, Ashley F. Stringer, Kevin B. Stunkel, Ron D. Tejral

Department of Agricultural and Biological Systems Engineering: Faculty Publications

High streambank erosion and failure rates on streams in the Ozark ecoregion of Oklahoma may be attributed to land use change and degradation of riparian areas. Numerous benefits may be achieved from streambank stabilization, but methods are needed to determine the most critical reaches for investing limited funds. Rapid geomorphic assessments (RGAs) have been used to aid in prioritizing stream reaches. This research (1) applied an existing RGA, the channel stability index (CSI), on several reaches along the Barren Fork Creek and Spavinaw Creek, and (2) modified the existing RGA to create an ecoregion-specific RGA called the Oklahoma Ozark streambank …

Climate Change Impacts On Streamflow, Water Quality, And Best Management Practices For The Shell And Logan Creek Watersheds In Nebraska, M. W. Van Liew, S. Feng, T. B. Pathak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Improvements in the management of water, sediment, and nutrients under future climatic conditions are needed to ensure increased crop and livestock production to meet greater global needs and the future availability of water for competing demands and protection against adverse water quality impairments. This study determined the impacts of future climate change scenarios on streamflow, water quality, and best management practices (BMPs) for two watersheds in Nebraska, USA. The Soil and Water Assessment Tool (SWAT) was employed to simulate streamflow, sediment, total nitrogen (N) and total phosphorus (P) from the Shell Creek Watershed near Columbus, Nebraska and the Logan Creek …

Carbon, Water, And Heat Flux Responses To Experimental Burning And Drought In A Tallgrass Prairie, Marc L. Fischer, M S. Torn, David P. Billesbach, Geoffrey Doyle, Brian Northup, Sebastien C. Biraud

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Drought and fire are common disturbances to grassland ecosystems. We report two years of eddy covariance ecosystem–atmosphere fluxes and biometric variables measured in nearby burned and unburned pastures in the US Southern Great Plains. Over the course of the experiment, annual precipitation (∼600 mm yr⁻¹) was lower than the long term mean (∼860 mm yr⁻¹). Soil moisture decreased from productive conditions in March 2005 dry, unproductive conditions during the growing season starting in March 2006. Just prior to the burn in early March 2005, burned and unburned pastures contained 520 ± 60 and 360 ± 40 …

Global Estimation Of Evapotranspiration Using A Leaf Area Index-Based Surface Energy And Water Balance Model, H. Yan, S.Q. Wang, David P. Billesbach, Walter Oechel, J.H. Zhang, Tilden Meyers, Ta. Martin, Roser Matamala, Dennis D. Baldocchi, G. Bohrer, D. Dragoni, R. Scott

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Studies of global hydrologic cycles, carbon cycles and climate change are greatly facilitated when global estimates of evapotranspiration (E) are available. We have developed an air-relative-humidity-based two-source (ARTS) E model that simulates the surface energy balance, soil water balance, and environmental constraints on E. It uses remotely sensed leaf area index (L_ai) and surface meteorological data to estimate E by: 1) introducing a simple biophysical model for canopy conductance (G_c), defined as a constant maximum stomatal conductance g_smax of 12.2mm s⁻¹multiplied by air relative humidity (R_{h …}

Fabrication And Characterization Of Dna-Loaded Zein Nanospheres, Mary C. Regier, Jessica D. Taylor, Tyler Borcyk, Yiqi Yang, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background: Particulates incorporating DNA are promising vehicles for gene delivery, with the ability to protect DNA and provide for controlled, localized, and sustained release and transfection. Zein, a hydrophobic protein from corn, is biocompatible and has properties that make it a promising candidate material for particulate delivery, including its ability to form nanospheres through coacervation and its insolubility under physiological conditions, making it capable of sustained release of encapsulated compounds. Due to the promise of this natural biomaterial for drug delivery, the objective of this study was to formulate zein nanospheres encapsulating DNA as the therapeutic compound, and to …

Runoff Nutrient Loads As Affected By Residue Cover, Manure Application Rate, And Flow Rate, Chance Thayer, John E. Gilley, Lisa M. Durso, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure is applied to cropland areas with varying surface cover to meet single‐year or multiple‐year crop nutrient requirements. The objectives of this field study were to: (1) examine runoff water quality characteristics following land application of manure to sites with and without wheat residue, (2) compare the water quality impacts of land application of manure to meet 0‐, 1‐, 2‐, 4‐, and 8‐year P‐based requirements for corn, and (3) evaluate the effects of varying runoff rates on runoff nutrient loads. Three 30‐min simulated rainfall events, separated by 24 h intervals, were applied at an intensity of 70 mm h^{‐1 …}

Quantification And Heterogeneity Of Infiltration And Transport In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Peter Q. Storm, Brian E. Haggard, Todd Halihan, Ronald B. Miller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In order to protect drinking water systems and aquatic ecosystems, all critical nutrient source areas and transport mechanisms need to be characterized. It is hypothesized that hydrologic heterogeneities (e.g., macropores and gravel outcrops) in the subsurface of floodplains play an integral role in impacting flow and contaminant transport between the soil surface and shallow alluvial aquifers which are intricately connected to streams. Infiltration is often assumed to be uniform at the field scale, but this neglects the high spatial variability common in anisotropic, heterogeneous alluvial floodplain soils. In the Ozark ecoregion, for example, the erosion of carbonate bedrock (primarily limestone) …

Berm Method For Quantification Of Infiltration And Leaching At The Plot Scale In High Conductivity Soils, Derek M. Heeren, Garey A. Fox, Daniel E. Storm

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Measuring infiltration and leaching at the plot scale is difficult, especially for high hydraulic conductivity soils. Infiltration rate has been indirectly calculated at the plot scale by comparing surface runoff to rainfall. Direct measurement of infiltration and leaching beyond the point scale is typically limited to locations where land forming has been performed, e.g. infiltration ponds and fields with basin irrigation. The standard method for field measurement of infiltration is a double ring infiltrometer, which is limited in size (typically 30 cm diameter). In this research, a new method is proposed that uses a temporary berm constructed of a water …

Comparison Of 2-Way Versus Metered 3-Way Boom Shut-Off Valves For Automatic Section Control On Agricultural Sprayers, Ajay Sharda, Joe D. Luck, John P. Fulton, Timothy P. Mcdonald, Scott A. Shearer, Daniel K. Mullenix

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Modern spray rate controllers along with technologies such as automatic section control (ASC) provide benefits such as overlap reduction on agricultural sprayers. However, product (liquid) dynamics within the boom plumbing affect off-rate errors and application uniformity during rate changes and ASC actuation. Therefore, this study was conducted to compare nozzle flow stability and uniformity across the boom when using two different boom shut-off valves (2-way and metered 3-way) on an 18.3-m sprayer boom. Pressure transducers were mounted at 1) the boom manifold, 2) randomly at 12 nozzle bodies across the spray boom, and 3) upstream and downstream of the flow …

Selecting Sprinkler Packages For Center Pivots, Derrel L. Martin, William L. Kranz, Allen L. Thompson, Hong Liang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Center pivots are the primary method of irrigation across the U.S. Great Plains. Center-pivot irrigation is also the fastest growing method of irrigation in the U.S. and around the world. Pivots have the potential to be very efficient and uniform if sprinkler devices are properly selected for local field conditions. New water application devices provide for selection that minimizes runoff and controls droplet sizes to reduce evaporation and drift losses. We present updates to models for computing runoff potential based on characteristics of sprinkler devices and soil textural classes. A dimensionless solution to the Green-Ampt infiltration method for center pivots …

Sensitivity Of Grass- And Alfalfa-Reference Evapotranspiration To Weather Station Sensor Accuracy, Dana O. Porter, Prasanna H. Gowda, Thomas H. Marek, Terry A. Howell, Jerry Moorhead, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A sensitivity analysis was conducted to determine the relative effects of measurement errors in climate data input parameters on the accuracy of calculated reference crop evapotranspiration (ET) using the ASCE-EWRI Standardized Reference ET Equation. Data for the period of 1995 to 2008 from an automated weather station located at the USDA-ARS Conservation and Production Research Laboratory at Bushland, Texas were used for the analysis. Results

indicated that grass (ET_os) and alfalfa (ET_rs) reference crop ET were most sensitive to measurement errors in wind speed and air temperature followed by incoming shortwave (solar) radiation, and that data …

Evaluation Of A Rhodamine-Wt Dye/Glycerin Mixture As A Tracer For Testing Direct Injection Systems For Agricultural Sprayers, Joe D. Luck, Scott A. Shearer, Brian D. Luck, Fred A. Payne

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The purpose of this study was to provide valuable insight regarding the use of Rhodamine WT (red) dye as a tracer for evaluating injected concentrations. More specifically, the effects of mixing the dye with glycerin to simulate the viscosity of a pesticide (e.g., glyphosate) or injecting the dye/glycerin mixture into deionized (DI) versus tap water on developing appropriate calibration equations were evaluated. Test results indicated that mixing the dye in a solution of glycerin and DI water significantly affected absorbance measurements compared to the dye mixed solely in DI water. The error in estimating absorbance was 7.4% between the two …

Swat: Model Use, Calibration, And Validation, Jeffrey G. Arnold, Daniel N. Moriasi, Philip W. Gassman, Karim C. Abbaspour, Michael J. White, Raghavan Srinivasan, Chinnasamy Santhi, Daren Harmel, Ann Van Griensven, Michael W. Van Liew, Narayanan Kannan, Manoj K. Jha

Department of Agricultural and Biological Systems Engineering: Faculty Publications

SWAT (Soil and Water Assessment Tool) is a comprehensive, semi-distributed river basin model that requires a large number of input parameters, which complicates model parameterization and calibration. Several calibration techniques have been developed for SWAT, including manual calibration procedures and automated procedures using the shuffled complex evolution method and other common methods. In addition, SWAT-CUP was recently developed and provides a decision-making framework that incorporates a semi-automated approach (SUFI2) using both manual and automated calibration and incorporating sensitivity and uncertainty analysis. In SWAT-CUP, users can manually adjust parameters and ranges iteratively between autocalibration runs. Parameter sensitivity analysis helps focus the …