Engineering Commons^™

Electrical And Material Properties Of Hydrothermally Grown Single Crystal (111) Uo2, Christina L. Dugan, George Glenn Peterson, Alyssa Mock, Christopher Young, J. Matthew Mann, Michael Nastasi, Mathias Schubert, Lu Wang, Wai-Ning Mei, Iori Tanabe, Peter A. Dowben, James Petrosky

Department of Electrical and Computer Engineering: Faculty Publications

The semiconductor and optical properties of UO₂ are investigated. The very long drift carrier lifetimes, obtained from current-voltage I(V) and capacitance-voltage C(V) measurements, along with the well-defined optical properties provide little evidence of an abundance of material defects away from the surface region. Schottky barrier formation may be possible, but very much dependent on the choice of contact and surface stoichiometry and we find that Ohmic contacts are in fact favored. Depth resolved photoemission provided evidence of a chemical shift at the surface. Density functional theory, with the Heyd-Scuseria-Ernzerhof (HSE) functional, indicates a band gap of a 2.19 eV …

Rainwater Harvesting System Scenario Analysis On Runoff Reduction Potential In Surabaya, Indonesia: A Geospatial Analysis For Brantas Hilir Watershed, Putri Sukmahartati

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Global warming has become an environmental concern over the past several decades and its impact on the water cycle is very crucial to the well-being of the human population. In the hydrological cycle, water evaporates by the heat of the sun and atmosphere, where it is accumulated in the atmosphere via clouds and it then falls as rain. With warmer temperatures, more intensive evaporation and downpours occur. In addition, impervious surfaces are increasing as a result of urban development. Those surfaces cause more water to flow faster into open water bodies, creating more extensive flooding, and additionally reducing water quality. …

Dynamic Classification Of Moisture Stress Using Canopy And Leaf Temperature Responses To A Step Changes Of Incident Radiation, Erin E. Stevens, George E. Meyer, Ellen T. Paparozzi

Honors Program: Senior Projects (Public)

Environmental conditions affect plant productivity and understanding how plants respond to drought stress can be measured in different ways. This study focused on measuring leaf response time to induced water stress. Leaf response time to a step increase and step decrease in radiation was computed for four species of well-watered and water-stressed plants in a controlled environment. The canopy temperature was measured with an infrared thermometer and a thermal imaging camera. Thermal images were analyzed to determine the average temperature of a selected single, unobstructed leaf at the top of the canopy. Both the canopy response time and the single …

Imidacloprid Sorption And Transport In Cropland, Grass Buffer, And Riparian Buffer Soils, Laura E. Satkowski, Keith W. Goyne, Stephen H. Anderson, Robert N. Lerch, Elisabeth B. Webb, Daniel D. Snow

Daugherty Water for Food Global Institute: Faculty Publications

An understanding of neonicotinoid sorption and transport in soil is critical for determining and mitigating environmental risk associated with the most widely used class of insecticides. The objective of this study was to evaluate mobility and transport of the neonicotinoid imidacloprid (ICD) in soils collected from cropland, grass vegetative buffer strip (VBS), and riparian VBS soils. Soils were collected at six randomly chosen sites within grids that encompassed all three land uses. Single-point equilibrium batch sorption experiments were conducted using radio-labeled (¹⁴C) ICD to determine solid–solution partition coefficients (K_d). Column experiments were conducted using soils collected …

Method For Data - Driven Learning - Based Control Of Hvac Systems Using High - Dimensional Sensory Observations, Amir-Massoud Farahmand, Saleh Nabi, Piyush Grover, Daniel Nikolaev Nikovski

Department of Mechanical and Materials Engineering: Faculty Publications

A controller for controlling an operation of an air - conditioning system conditioning an indoor space includes a data input to receive state data of the space at multiple points in the space , a memory to store a code of a reinforcement learning algorithm and a history of the state data and a history of control commands having been applied to the air - conditioning system , wherein the history of the control commands is associated with the state data and history of rewards , a processor coupled to the memory determines a value function outputting a cumulative value …

Multi-Point Vibration Measurement And Mode Magnification Of Civil Structures Using Video-Based Motion Processing, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Image-based vibration measurement has gained increased attentions in civil and construction communities. A recent video-based motion magnification method was developed to measure and visualize small structure motions. This new approach presents a potential for low-cost vibration measurement and mode shape identification. Pilot studies using this approach on simple rigid body structures were reported. Its validity on complex outdoor structures has not been investigated. In this study, a non-contact video-based approach for multi-point vibration measurement and mode magnification is introduced. The proposed approach can output a full-field vibration map that increases the efficiency of the current structural health monitoring (SHM) practice. …

Evaluation Of A Hybrid Reflectance-Based Crop Coefficient And Energy Balance Evapotranspiration Model For Irrigation Management, J. Burdette Barker, Christopher M. U. Neale, Derek M. Heeren, Andrew E. Suyker

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate generation of spatial soil water maps is useful for many types of irrigation management. A hybrid remote sensing evapotranspiration (ET) model combining reflectance-based basal crop coefficients (K_cbrf) and a two-source energy balance (TSEB) model was modified and validated for use in real-time irrigation management. We modeled spatial ET for maize and soybean fields in eastern Nebraska for the 2011-2013 growing seasons. We used Landsat 5, 7, and 8 imagery as remote sensing inputs. In the TSEB, we used the Priestly-Taylor (PT) approximation for canopy latent heat flux, as in the original model formulations. We also used the …

Modelling And Visualizing Selected Molecular Communication Processes In Biological Organisms: A Multi-Layer Perspective, Aditya Immaneni

School of Computing: Dissertations, Theses, and Student Research

The future pervasive communication and computing devices are envisioned to be tightly integrated with biological systems, i.e., the Internet of Bio-Nano Things. In particular, the study and exploitation of existing processes for the biochemical information exchange and elaboration in biological systems are currently at the forefront of this research direction. Molecular Communication (MC), which studies biochemical information systems with theory and tools from computer communication engineering, has been recently proposed to model and characterize the aforementioned processes. Combined with the rapidly growing field of bio-informatics, which creates a rich profusion of biological data and tools to mine the underlying information, …

Ring And Peg Simulation For Minimally Invasive Surgical Robot, Evan Brown

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Surgical procedures utilizing minimally invasive laparoscopic techniques have shown less complications, better cosmetic results, and less time in the hospital than conventional surgery. These advantages are partially offset by inherent difficulties of the procedures which include an inverted control scheme, instrument clashing, and loss of triangulation. Surgical robots have been designed to overcome the limitations, the Da Vinci being the most widely used. A dexterous in vivo, two-armed robot, designed to enter an insufflated abdomen with a limited insertion profile and expand to perform a variety of operations, has been created as a less expensive, versatile alternative to the Da …

Development Of A Sprayer Performance Diagnostic Tool Using Improved Mapping And Error Quantification Practices, Aaron Shearer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

While sprayer technologies have advanced greatly over the past decade and a half, chemical application errors are still prominent in many in-field operations. Over-application of pesticides can cause harm to the crop, reducing yield, and result in added pollution to the environment. Under-application of pesticides fails to control pests within the field, again lowering crop yields, and causing profit loss for the producer. Current operator feedback from in-field pesticide application operations conveys limited information and often times does not allow the operator to visualize a true representation of their performance. Farm Management Information Systems (FMIS) typically do not account for …

Strategic Audit Of National Instruments, Grant Fishburn

Honors Program: Senior Projects (Public)

The research and analyses compiled in this paper provide a holistic view into the current situation that National Instruments faces as a company and what strategies it can take to overcome current and pressing issues. The goal of the audit is to determine a strategic recommendation for National Instruments that will achieve any number of goals and objectives set by the auditor in accordance to the situation at hand. In addition to this strategic recommendation, an implementation and contingency plan are developed to further expand upon how such a strategy would be created in the real world. The strategic recommendation …

A Strategic Audit Of Medtronic Plc, Jozzy Carter

Honors Program: Senior Projects (Public)

Humans will always have a need for healthcare, and as the world continues to innovate in the tech space, consumers will demand advances in medicine and medical devices. Medtronic is at the forefront of this innovation but faces intense competition in the medical technologies industry. This poses the question: what can Medtronic do to continue its growth and stay competitive in this space? This paper offers an analysis of Medtronic as a medical device company by offering insight to its competitive advantage, financials, business mix, and value chain. It also analyzes the forces that affect Medtronic using SWOT, PEST, and …

Structural Identification And Assessment Of The Inverted Tee Girder Bridge System, Garrett P. D. Martindale

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The Inverted Tee (IT) girder bridge system was originally developed in 1996 by the University of Nebraska–Lincoln (UNL) and Nebraska Department of Roads (NDOR) engineers. This bridge system currently accounts for over 110 bridges in Nebraska used for both state highways and local county roads. Excessive transverse and longitudinal deck cracking has been observed and noted in numerous bridge inspection reports. Since the IT girder bridge system is relatively new, limited data and knowledge exist on its structural performance and behavior. This study evaluates the IT girder bridge system by conducting twenty field observations as well as recording accelerometer time …

Mash Test No. 3-10 Of A Non-Proprietary, High-Tension, Cable Median Barrier For Use In 6h:1v V-Ditch (Test No. Mwp-9), Mojdeh Asadollahi Pajouh, Karla A. Lechtenberg, Ronald K. Faller, James C. Holloway, Robert W. Bielenberg, Scott K. Rosenbaugh

Nebraska Department of Transportation: Research Reports

The Midwest Pooled Fund Program has been developing a prototype design for a non-proprietary, high-tension, cable median barrier for use in a 6H:1V median V-ditch. This system incorporates four evenly spaced cables, Midwest Weak Posts (MWPs) spaced at 8 to 16 ft (2.4 to 4.9 m) intervals, and a bolted, tabbed bracket to attach the cables to each post. Full-scale crash testing was needed to evaluate the barrier’s safety performance. According to the Manual for Assessing Safety Hardware 2016 (MASH) testing matrix for cable barriers installed within a 6H:1V median V-ditch, a series of eight full-scale crash tests are required …

Phase Ii Evaluation Of Floor Pan Tearing For Cable Barrier Systems, Dylan T. Meyer, Mojdeh Asadollahi Pajouh, Karla A. Lechtenberg, Ronald K. Faller, Robert W. Bielenberg, James C. Holloway

Nebraska Department of Transportation: Research Reports

The objective of this research effort was to mitigate the potential for floor pan tearing and penetration into the occupant compartment by modifying the posts utilized in a prototype cable barrier system. A series of dynamic component tests were conducted on the modified Midwest Weak Post (MWP). A bogie vehicle was equipped with a simulated floor pan designed to replicate the height, thickness, and strength of the floor pan of a Kia Rio. Two methods of post modification were investigated, including edge protection on the top of the MWP as well as weakening of the MWP at the ground line. …

High-Resolution Water Footprints Of Production Of The United States

Daugherty Water for Food Global Institute: Faculty Publications

The United States is the largest producer of goods and services in the world. Rainfall, surface water supplies, and groundwater aquifers represent a fundamental input to economic production. Despite the importance of water resources to economic activity, we do not have consistent information on water use for specific locations and economic sectors. A national, spatially detailed database of water use by sector would provide insight into U.S. utilization and dependence on water resources for economic production. To this end, we calculate the water footprint of over 500 food, energy, mining, services, and manufacturing industries and goods produced in the United …

Broadband Plasmonic-Enhanced Forward And Backward Multiplex Coherent Anti-Stokes Raman Scattering Microscopy, Baoshan Guo, Lan Jiang, Yanhong Hua, Xin Li, Tianhong Cui, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Coherent anti-Stokes Raman scattering (CARS) microscopy is an attractive technique for label-free biochemical-specific characterization of biological specimens. However, it has very low sensitivity in monitoring and imaging molecules present in extremely low concentrations or at fast speeds. To improve this sensitivity, especially for multiplex CARS, the intensity of the pump beam and broadband Stokes beam should be enhanced simultaneously. Therefore, the gold shell particle and gold surface are demonstrated to enhance the forward and backward CARS, respectively. Results show that a signal enhancement factor of ∼25;000 can be achieved for the gold surface and an even higher enhancement factor can …

The Effect Of Poly (Glycerol Sebacate) Incorporation Within Hybrid Chitin–Lignin Sol–Gel Nanofibrous Scaffolds, Tuerdimaimaiti Abudula, Lassaad Gzara, Giovanna Simonetti, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Afsoon Fallahi, Ali Tamayol, Sidi A. Bencherif, Adnan Memic

Department of Mechanical and Materials Engineering: Faculty Publications

Chitin and lignin primarily accumulate as bio-waste resulting from byproducts of crustacean crusts and plant biomass. Recently, their use has been proposed for diverse and unique bioengineering applications, amongst others. However, their weak mechanical properties need to be improved in order to facilitate their industrial utilization. In this paper, we fabricated hybrid fibers composed of a chitin–lignin (CL)-based sol–gel mixture and elastomeric poly (glycerol sebacate) (PGS) using a standard electrospinning approach. Obtained results showed that PGS could be coherently blended with the sol–gel mixture to form a nanofibrous scaffold exhibiting remarkable mechanical performance and improved antibacterial and antifungal activity. The …

Education Institutions Creation Of Partnerships, Iwasan D. Kejawa Ed.D

Department of Educational Administration: Faculty Publications

This issue is embracing the creation of partnerships with establishments worldwide for the provisions of life embodiments to graduates. At moment, there may be lack of friendship or partnership with establishments to create incentives for newly graduates of so many colleges and universities (Hirsh & Weber, 1999). Partnership with external companies will surely bring enormous grants to the colleges and universities and it will also encourage friendly establishments to provide incentives and perks to colleges, universities and alumni. It may be concluded that the advantages of creating rapport with external congruences is the comraderies and also compromises that will be …

An Analysis Of Project Setup And Organization In Software, Adam Fitzgibbon

Honors Program: Senior Projects (Public)

The setup of a software project can greatly influence how efficiently software can be built. In this paper, I will be discussing my experiences with various software projects and their setups. These experiences will be used as a basis to draw conclusions on the strengths and weaknesses of specific project setups in certain situations.

Because of the complexity of building software, there isn’t a project setup that works optimally for solving every type of software-based problem. The best approach is to know what variations would best fit the situation and make design decisions from there.

Qtsac: An Energy-Efficient Mac Protocol For Delay Minimization In Wireless Sensor Networks, Yuxin Liu, Kaoru Ota, Kuan Zhang, Ming Ma, Naixue Xiong, Anfeng Liu, Jun Long

Department of Electrical and Computer Engineering: Faculty Publications

Millions of sensors are deployed to monitor the smart grid. They consume huge amounts of energy in the communication infrastructure. Therefore, the establishment of an energy-efficient medium access control (MAC) protocol for sensor nodes is challenging and urgently needed. The Quorum-based MAC protocol independently and adaptively schedules nodes’ wake-up times and decreases idle listening and collisions, thereby increasing the network throughput and extending the network lifetime. A novel Quorum time slot adaptive condensing (QTSAC)-based MAC protocol is proposed for achieving delay minimization and energy efficiency for the wireless sensor networks (WSNs). Compared to previous protocols, the QTSAC-based MAC protocol has …

The Positive Role Of Curcumin-Loaded Salmon Nanoliposomes On The Culture Of Primary Cortical Neurons, Mahmoud Hasan, Shahrzad Latifi, Cyril J.F. Kahn, Ali Tamayol, Rouhollah Habibey, Elodie Passeri, Michel Linder, Elmira Arab-Tehrany

Department of Mechanical and Materials Engineering: Faculty Publications

Curcumin (diferuloylmethane) is a natural bioactive compound with many health-promoting benefits. However, its poor water solubility and bioavailability has limited curcumin’s biomedical application. In the present study, we encapsulated curcumin into liposomes, formed from natural sources (salmon lecithin), and characterized its encapsulation efficiency and release profile. The proposed natural carriers increased the solubility and the bioavailability of curcumin. In addition, various physico-chemical properties of the developed soft nanocarriers with and without curcumin were studied. Nanoliposome-encapsulated curcumin increased the viability and network formation in the culture of primary cortical neurons and decreased the rate of apoptosis.

Nanostructural Origin Of Semiconductivity And Large Magnetoresistance In Epitaxial Nico2O4/Al2O3 Thin Films, Congmian Zhen, Xiaozhe Zhang, Wengang Wei, Wenzhe Guo, Ankit Pant, Xiaoshan Xu, Jian Shen, Li Ma, Denglu Hou

Xiaoshan Xu Papers

Despite low resistivity (~1 mΩ cm), metallic electrical transport has not been commonly observed in inverse spinel NiCo₂O₄, except in certain epitaxial thin films. Previous studies have stressed the effect of valence mixing and the degree of spinel inversion on the electrical conduction of NiCo₂O₄ films. In this work, we studied the effect of nanostructural disorder by comparing the NiCo₂O₄ epitaxial films grown on MgAl₂O₄ (1 1 1) and on Al₂O₃ (0 0 1) substrates. Although the optimal growth conditions are similar for the …

Respirable Dust Monitoring In Construction Sites And Visualization In Building Information Modeling Using Real-Time Sensor Data, Nour Smaoui, Kyungki Kim, Omprakash Gnawali, Young-Joo Lee, Wonho Suh

Durham School of Architectural Engineering and Construction: Faculty Publications

Construction activities, involving cutting, drilling, and grinding of materials, often produce toxic respirable dust that can cause fatal diseases and illnesses. To protect workers from breathing excessive amounts of respirable dust at job sites, superintendents should continuously monitor the level of respirable dust in workspaces and make timely interventions for overexposed workers. However, current practices of respirable dust monitoring have critical drawbacks, and superintendents cannot accurately estimate workers’ exposures to respirable dust or make prompt decisions to protect the workers. Therefore, there is a need for real-time air dust monitoring that can be deployed ubiquitously at a construction site and …

Electron Effective Mass In In0.33ga0.67n Determined By Mid- Infrared Optical Hall Effect, Nerijus Armakavicius, Vallery Stanishev, Sean Knight, Mathias Schubert, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

Mid-infrared optical Hall effect measurements are used to determine the free charge carrier parameters of an unintentionally doped wurtzite-structure c-plane oriented In_0.33Ga_0.67N epitaxial layer. Room temperature electron effective mass parameters of m_ ¼ ð0:20560:013Þm0 andm_k ¼ ð0:20460:016Þm0 for polarization perpendicular and parallel to the c-axis, respectively,were determined. The free electron concentration was obtained as (1.760.2)_1019 cm^-3. Within our uncertainty limits, we detect no anisotropy for the electron effective mass parameter and we estimate the upper limit of the possible effective mass anisotropy as 7%. We discuss the influence of conduction band nonparabolicity on …

Piezocone Penetration Testing Device, Chung R. Song, Benyam M. Bekele, Brian Sawyer

Nebraska Department of Transportation: Research Reports

Hydraulic characteristics of soils can be estimated from piezocone penetration test (called PCPT

hereinafter) by performing dissipation test or on-the-fly using advanced analytical techniques. This

research report presents a method for fast estimation of hydraulic conductivity of overconsolidated soils

based on the piezocone penetration test. The method relies on an existing relationship developed for the

determination of hydraulic conductivity of normally consolidated soils on-the-fly. The present research

revises this relationship so that it can be applied for overconsolidated soils by incorporating a proper

correction equation. The revised relationship provides a pore pressure representing the hydraulic

conductivity of a hypothetical “equivalent …

Condensation And Subsequent Freezing Delays As A Result Of Using Femtosecond Laser Functionalized Surfaces, Chongji Huang, Ryan Bell, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, the authors report on the use of femtosecond laser surface processing (FLSP) to enhance the anti-icing properties of a commonly used aircraft alloy, Al 7075-O Clad. By changing the surface morphology through FLSP and the surface chemistry through siloxane vapor deposition, the wettability of Al 7075-O Clad was altered. Tall mound and short mound FLSP functionalized surfaces were created through two sets of laser parameters. Condensation and the subsequent freezing of condensates on FLSP Al 7075-O Clad was studied. Both structure height and surface wettability were shown to play a role in the delay of freezing. Freezing …

Climate-Driven Crop Yield And Yield Variability And Climate Change Impacts On The U.S. Great Plains Agricultural Production, Meetpal Singh Kukal, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Climate variability and trends affect global crop yields and are characterized as highly dependent on location, crop type, and irrigation. U.S. Great Plains, due to its significance in national food production, evident climate variability, and extensive irrigation is an ideal region of investigation for climate impacts on food production. This paper evaluates climate impacts on maize, sorghum, and soybean yields and effect of irrigation for individual counties in this region by employing extensive crop yield and climate datasets from 1968–2013. Variability in crop yields was a quarter of the regional average yields, with a quarter of this variability explained by …

Ureteral Tunnel Length Versus Ureteral Orifice Configuration In The Determination Of Ureterovesical Junction Competence: A Computer Simulation Model, Carlos A. Villanueva, J. Tong, Carl A. Nelson, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction The long-held belief that a ureteral re-implant tunnel should be five times the diameter of the ureter, as proposed by Paquin in 1959, ignores the effect of the orifice on the occurrence of reflux. In 1969, Lyon proposed that the shape of the ureteral orifice (UO) is more important than the intravesical tunnel. However, both theories missed quantitative evidence from principles of physics. The goal of the current study was to test Lyon’s theory through numerical models (i.e. to quantify the sensitivity of ureterovesical junction (UVJ) competence to intravesical tunnel length and to the UO).

Materials and methods The …

Internet Of Underground Things: Sensing And Communications On The Field For Precision Agriculture, Mehmet C. Vuran, Abdul Salam, Rigoberto Wong, Suat Irmak

School of Computing: Conference and Workshop Papers

The projected increases in World population and need for food have recently motivated adoption of information technology solutions in crop fields within precision agriculture approaches. Internet of underground things (IOUT), which consists of sensors and communication devices, partly or completely buried underground for real-time soil sensing and monitoring, emerge from this need. This new paradigm facilitates seamless integration of underground sensors, machinery, and irrigation systems with the complex social network of growers, agronomists, crop consultants, and advisors. In this paper, state-of-the-art communication architectures are reviewed, and underlying sensing technology and communication mechanisms for IOUT are presented. Recent advances in the …