Engineering Commons^™

Anchoring And Stiffening Techniques For Portable Concrete Barriers, Surajkumar Bhakta

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

Portable concrete barrier (PCB) systems are utilized on federal and state highways in circumstances such as placing adjacent to vertical drop-offs and in construction zones. PCB systems are most commonly used in a free-standing configuration, which are known to have relatively large deflections when impacted. Large deflections are undesirable when dealing with limited space. In order to allow PCBs to be used in space restricted locations, seven PCB anchoring and stiffening techniques were tested and evaluated as per Manual for Assessing Safety Hardware (MASH) testing standards. Results will allow the New Jersey Department of Transportation to update guidance for their …

Numerical Modeling To Evaluate The Performance Of Slow-Release Candles For Groundwater Remediation, Chuyang Liu

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

Slow-release candles (SRC) have been developed as a cost-effective technology to treat groundwater contaminants by passively delivering oxidants into the subsurface over a long time. In this thesis, a numerical model has been developed to simulate oxidant release kinetics, transport, and reaction in a field scale. Parameters of the model were obtained from a field site with SRC installed. Modeling results showed that the radius of influence of oxidants was influenced by the relative contribution of reaction and solute transport, and the limited lateral spreading could be an issue to restrict the application of SRC.

Enhanced aeration could increase or …

Spatial And Temporal Variation In Precipitation In Togo, Koffi Djaman, Vivek Sharma, Daran Rudnick, Komlan Koudahe, Suat Irkmak, Kokou Adambounou Amouzou, Jean Mianikpo Sogbedji

Department of Biological Systems Engineering: Papers and Publications

Precipitation is one of the important variables in hydrological cycle and has important application in both irrigated and rainfed agricultural crop production. Better understanding of spatio-temporal variability of precipitation across Togo is important and useful for water users and most agricultural activities. Thus, the objective this study was to analyze the spatial and temporal variation in monthly and annual precipitation across Togo for the period of 1961-2001. Monthly precipitation data was provided by the national direction of meteorology. The performed analysis revealed a decline in annual total precipitation across almost all agro-ecological zones in Togo with the Maritime Region revealed …

Cam-Based Pose-Independent Counterweighting For Partial Body-Weight Support In Rehabilitation, Ashish Shinde

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

This thesis presents the design and testing of a body weight support system for gait training in a two-dimensional workspace. Extension of the system to a three-dimensional workspace is not within the scope of this thesis.

Gait dysfunctions are changes in normal walking patterns, often related to a disease or abnormality in different areas of the body. There are numerous body weight support (BWS) systems present in the market which are applied to rehabilitation scenarios in mobility recovery like in gait training. But most of these BWE systems are costly and generally are stationary devices. A major drawback of such …

Multiple Scattering Theory For Polycrystalline Materials With Strong Grain Anisotropy: Theoretical Fundamentals And Applications, Huijing He

Department of Mechanical and Materials Engineering: Faculty Publications

This work is a natural extension of the author’s previous work: “Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications” (arXiv:1706.09137 [physics.geo-ph]), which established the foundation for developing multiple scattering model for heterogeneous elastic continua with either weak or strong fluctuations in mass density and elastic stiffness. Polycrystalline material is another type of heterogeneous materials that widely exists in nature and extensively used in industry. In this work, the corresponding multiple scattering theory for polycrystalline materials with randomly oriented anisotropic crystallites is developed. To validate the theory, the theoretical results for a series of …

Floating-Gate Transistor Photodetector, Jinsong Huang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

A field effect transistor photodetector that can operate in room temperature includes a source electrode , a drain electrode , a channel to allow an electric current to flow between the drain and source electrodes , and a gate electrode to receive a bias voltage for controlling the current in the channel . The photodetector includes a light - absorbing mate rial that absorbs light and traps electric charges . The light absorbing material is configured to generate one or more charges upon absorbing light having a wavelength within a specified range and to hold the one or more charges …

Effects Of Nitrogen And Phosphorus Fertilizer And Topsoil Amendment On Native Plant Cover In Roadside Revegetation Projects, Heidi L. Hillhouse, Walter H. Schacht, Jonathan M. Soper, Carol E. Wienhold

Department of Agronomy and Horticulture: Faculty Publications

Establishing vegetation on roadsides following construction can be challenging, especially for relatively slow growing native species. Topsoil is generally removed during construction, and the surface soil following construction (“cut-slope soils”) is often compacted and low in nutrients, providing poor growing conditions for vegetation. Nebraska Department of Transportation (NDOT) protocols have historically called for nitrogen (N) and phosphorus (P) fertilization when planting roadside vegetation following construction, but these recommendations were developed for cool-season grass plantings and most current plantings use slower-establishing, native warmseason grasses that may benefit less than expected from current planting protocols. We evaluated the effects of nitrogen and …

Event And Time-Triggered Control Module Layers For Individual Robot Control Architectures Of Unmanned Agricultural Ground Vehicles, Tyler Troyer

Department of Biological Systems Engineering: Dissertations and Theses

Automation in the agriculture sector has increased to an extent where the accompanying methods for unmanned field management are becoming more economically viable. This manifests in the industry’s recent presentation of conceptual cab-less machines that perform all field operations under the high-level task control of a single remote operator. A dramatic change in the overall workflow for field tasks that historically assumed the presence of a human in the immediate vicinity of the work is predicted. This shift in the entire approach to farm machinery work provides producers increased control and productivity over high-level tasks and less distraction from operating …

Rate Based Impact Analysis, Nishant Sharma

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Impact Analysis (IA) identifies control and data dependencies to determine the system components that could be affected by a change. Changes to robotic systems as they are updated often alter the flow of control and sensor data. Changes to the rates at which data is published from sensors, controllers, and other parts of the system are particularly subtle and difficult to detect. These rate changes, even if minor (e.g. lowering the frame rate of a camera), can propagate throughout the system and have broad impacts. However, for robotic systems, these changes in flow rate cannot be precisely tracked by just …

Increased Span Length For The Mgs Long-Span Guardrail System Part Iii: Failure Analysis, Sagheer A. Ranjha, Robert W. Bielenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

The objective of this research study was to review and analyze the system failure observed during crash testing of an increased span length for the MGS long-span guardrail system in test no. MGSLS-2. Test no. MGSLS-2 was a full-scale crash test conducted on the MGS long-span guardrail with a span length of 311⁄4 ft (9.5 m). This test utilized universal breakaway steel posts (UBSPs) adjacent to the long span in lieu of the controlled release terminal (CRT) wood posts used in previous long span systems.

An engineering analysis was undertaken to review the downstream end anchorage failure observed in test …

Cross-Species Complementation Reveals Conserved Functions For Early Flowering 3 Between Monocots And Dicots, He Huang, Malia A. Gehan, Sarah E. Huss, Sohpie Alvarez, Cesar Lizarraga, Ellen L. Gruebbling, John Gierer, Michael J. Naldrett, Rebacca K. Bindbeutel, Bradley S. Evans, Todd C. Mockler, Dmitri A. Nusinow

Nebraska Center for Biotechnology: Faculty and Staff Publications

Plant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana (Arabidopsis) and crop species, circadian clock factors are critical for growth, flowering, and circadian rhythms. Outside of Arabidopsis, however, little is known about the molecular function of clock gene products. Therefore, we sought to compare the function of Brachypodium distachyon (Brachypodium) and Setaria viridis (Setaria) orthologs of EARLY FLOWERING 3, a key clock gene in Arabidopsis. To identify both cycling genes and putative ELF3 functional orthologs in Setaria, a …

Media, Institutions And Voting: Perceptions Of Nonmetropolitan Nebraskans: 2017 Nebraska Rural Poll Results, Rebecca J. Vogt, Cheryl A. Burkhart-Kriesel, Randolph L. Cantrell, Bradley Lubben, L. J. Mcelravy, Timothy L. Meyer

Rural Futures Institute: Publications

Conclusion

Rural Nebraskans most trust information received from local news sources (TV and newspapers) and public sources (PBS and public radio). They least trust information from social networking sites and Internet blogs. Most rural Nebraskans are somewhat or very confident in their ability to recognize news that is made up.

Most rural Nebraskans have confidence in their local institutions (public safety agencies in their community; public schools in their community; and voting and election systems in their county). On the other hand, over one-quarter of rural Nebraskans have very little confidence in the following national institutions: U.S. House of Representatives, …

Physical Water Scarcity Metrics For Monitoring Progress Towards Sdg Target 6.4: An Evaluation Of Indicator 6.4.2 “Level Of Water Stress”, D. Vanhama, A. Y. Hoekstra, Y. Wada, F. Bouraoui, A. De Roo, Mesfin Mekonnen, W. J. Van De Bund, O. Batelaan, P. Pavelic, W. G.M. Bastiaanssen, M. Kummu, J. Rockström, J. Liu, B. Bisselink, P. Ronco, A. Pistocchi, G. Bidoglio

Daugherty Water for Food Global Institute: Faculty Publications

Target 6.4 of the recently adopted Sustainable Development Goals (SDGs) dealswith the reduction ofwater scarcity. To monitor progress towards this target, two indicators are used: Indicator 6.4.1 measuring water use efficiency and 6.4.2 measuring the level of water stress (WS). This paper aims to identify whether the currently proposed indicator 6.4.2 considers the different elements that need to be accounted for in a WS indicator.WS indicators compare water use with water availability.We identify seven essential elements: 1) both gross and net water abstraction (or withdrawal) provide important information to understand WS; 2) WS indicators need to incorporate environmental flow requirements …

Feature Extraction And Parallel Visualization For Large-Scale Scientific Data, Lina Yu

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Advanced computing and sensing technologies enable scientists to study natural and physical phenomena with unprecedented precision, resulting in an explosive growth of data. The unprecedented amounts of data generated from large scientific simulations impose a grand challenge in data analytics and visualization due to the fact that data are too massive for transferring, storing, and processing.

This dissertation makes the first contribution to the design of novel transfer functions and application-aware data replacement policy to facilitate feature classification on highly parallel distributed systems. We design novel transfer functions that advance the classification of continuously changed volume data by combining the …

Water Use In Irrigated Agriculture: An Approach To Water Productivity In Drip And Sprinkler Systems, Fernanda Lamede Ferreira De Jesus, Jéssica Garcia Nascimento, Rubens Duarte Coelho, Sergio Nascimento Duarte, Fernando Campos Mendonça

Daugherty Water for Food Global Institute: Faculty Publications

Irrigation plays an important role in agriculture and the increase in the irrigated area and scarce water resources have encouraged the use of irrigation systems and management systems that increase the efficiency of water use. Thus, maximize water productivity has been one of the most important challenges in agriculture. The present study aimed to relate information on water productivity for two irrigation systems, drip and sprinkler systems, with the purpose of understanding the characteristics of these systems and contributing to the advancement of studies and research carried out in the area. Technological innovations aimed at reducing consumption and increasing water …

Software For Extracting Deformation Gradient And Stress From Md Simulations: Simulations Using The Charmm Force Field, Mehrdad Negahban, Lili Zhang, Zesheng Zhang, John Jasa, Antoine Jérusalem

Department of Mechanical and Materials Engineering: Faculty Publications

Software was developed, and is provided under a general use license, to calculate continuum level deformation gradient and stress for any group of atoms in an MD simulation that uses the Charmm force fields. This software can also calculate the interaction stress applied by one group of atoms on any other group. To obtain deformation gradient and stress, the user needs to provide the selected group(s) of atoms in an atom group identification file, and provide the associated LAMMPS format files and force field parameter file. An example is included to demonstrate the use of the software.

Rapid Thermocycler System For Rapid Amplification Of Nucleic Acids And Related Methods, Joel R. Termaat, Scoltt E. Whitney, Hendrik J. Viljoen, Matthew R. Kreifels

Department of Chemical and Biomolecular Engineering: Patents

A thermo cycling device and method of operating a thermocycler instrument, the instrument including a sample holder, at least one thermal cycling element, and at least one first and second temperature sensors, for causing the sample holder containing the at least one sample to undergo polymerase chain reaction amplification by repeated cycling between at least a denaturation heating stage and an aunealing cooling stage. The first temperature corresponding with the temperature of the sample holder is monitored using the at least one first temperature sensor, and a second temperature corresponding with the temperature external of the sample holder is monitored …

Improving Wildflower Longevity In Roadside Seeding Areas, Walter Schacht, Jonathan M. Soper, Carol Wienhold

Nebraska Department of Transportation: Research Reports

Re-vegetation efforts on bare roadsides of newly-constructed highways are primarily focused on the stabilization of soil to reduce rates of erosion. The Nebraska Department of Transportation (NDOT) seeds roadsides with a diverse mixture of grasses and wildflowers for site stabilization as well as to enhance the visual quality of roadsides. Although grasses dominate roadside plantings in terms of cover and density, wildflowers are largely responsible for the visual enhancement of recently-seeded roadsides. In addition to the visual component, wildflowers provide essential ecological functions on roadsides. Wildflowers improve water and nutrient cycling in the compacted roadside soils by increasing water infiltration …

Biofuels From Crop Residue: Soil Organic Carbon And Climate Impacts In The Us And India, Adam Liska

Adam Liska Papers

The transformation of crop residue to soil organic carbon and CO₂ is a conserved process that occurs globally. Due to the mathematics of carbon intensity calculations found in government regulations, the amount of CO₂ emitted from crop residue per unit of energy in biofuel is largely independent of the amount of residue removed and the location of its removal, as shown by results from the US and India.

Soil organic carbon (SOC) levels are at equilibria determined by carbon inputs from plant material (+I_c) and loss from oxidation to CO₂

Are the US results relevant …

Energy Absorbing Guardrail System, John R. Rohde, John D. Reid, King K. Mak, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A highway crash attenuation system having W - beam rail elements attached to a plurality of vertical posts . An impact terminal with a feeder chute guides one or more of the W - beam rail elements through the impact terminal . The feeder chute has an impact shield extending along a traffic facing side of the chute from an upstream - most end to a downstream - most end of the chute closing the traffic - facing side of the chute . The system also has an anchor cable release mechanism for releasing the cable downstream of the first …

Shape-Adaptive Mechanism For Robotic Grasping, Carl A. Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

A grapser can include a first pantograph cell and a second pantograph cell coupled with the first pantogrpah cell. The first and second pantograph cells can be coupled together at a first pivot and a second pivot. The grasper can also include a finger extendable in a direction extending between the first pivot and the second pivot. The grasper can include a support base, where one or more links of the first pantograph cell can be slidably coupled with the support base for extending the grasper. In some embodiment, the grasper can be configured to extend along a curved path. …

Viscoelastic Analysis And Fatigue Characterization Of Bituminous Materials In Two Length Scales Under The Influence Of Aging, Santosh Reddy Kommidi

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

Fatigue cracking in asphalt concrete (AC) is of immense importance to pavement design and analysis because it is one of the most important forms of distress that can lead to structural failure in pavement. Once started, these types of cracks can be combined with other environmental factors leading to detrimental effects such as faster rates of pavement deterioration and shortened pavement life and functionality.

Currently AASHTO TP101, also known as linear amplitude sweep (LAS) specification, is being widely used to evaluate the ability of an asphalt binder to resist fatigue. The LAS method, although mechanistic in its approach, has certain …

Shopping For Food In Nonmetropolitan Nebraska: 2017 Nebraska Rural Poll Results, Rebecca J. Vogt, Cheryl A. Burkhart-Kriesel, Randolph L. Cantrell, Bradley Lubben, L.J. Mcelravy, Timothy L. Meyer, Vanessa Wielenga

Rural Futures Institute: Publications

Conclusion

Rural Nebraskans purchase their food from a variety of stores. Almost four in ten buy most of their food from a supercenter (like Wal-Mart or Costco). Just over three in ten typically shop at a supermarket and just under three in ten buy most of their food at a small grocery store. Differences in the type of store most utilized occur by community size. Persons living in or near larger communities are more likely than persons living in or near smaller communities to purchase the majority of their food from either a supermarket or supercenter.

Persons living in or …

Security For 5g Mobile Wireless Networks, Dongfeng Fang, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications

The advanced features of 5G mobile wireless network systems yield new security requirements and challenges. This paper presents a comprehensive survey on security of 5G wireless network systems compared to the traditional cellular networks. The paper starts with a review on 5G wireless networks particularities as well as on the new requirements and motivations of 5G wireless security. The potential attacks and security services with the consideration of new service requirements and new use cases in 5G wireless networks are then summarized. The recent development and the existing schemes for the 5G wireless security are presented based on the corresponding …

Loss Of Buffer Value Due To Aquifer Depletion: The Case Of High Plains Aquifer, Mani Rouhi Rad, Timothy Foster, Nicholas Brozovic

Daugherty Water for Food Global Institute: Faculty Publications

Existing literature in economics and engineering do not realistically capture the effects of aquifer depletion on loss of profits from agricultural production. While the former literature ignores the physical characteristics of aquifer and the relationship between aquifer levels and groundwater availability, the latter strand of literature does not consider farmers' decisionmaking as a result of aquifer depletion. Misspecification of these relationships and their effect on irrigation decisions can result in misunderstanding the consequences of aquifer depletion and may provide ineffective policies. This paper provides a framework to study the effects of aquifer depletion on the profit of agricultural production. We …

Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling

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

An Unmanned Aircraft System (UAS) is a Cyber-Physical System (CPS) in which a host of real-time computational tasks contending for shared resources must be cooperatively managed to obtain mission objectives. Traditionally, control of the UAS is designed assuming a fixed, high sampling rate in order to maintain reliable performance and margins of stability. But emerging methods challenge this design by dynamically allocating resources to computational tasks, thereby affecting control and mission performance. To apply these emerging strategies, a characterization and understanding of the effects of timing on control and trajectory following performance is required. Going beyond traditional control evaluation techniques, …

Frequency Sensitive Mechanism In Low-Intensity Ultrasound Enhanced Bioeffects, April D. Miller, Abdoulkadri Chama, Tobias M. Louw, Anuradha Subramanian, Hendrik J. Viljoen

Department of Chemical and Biomolecular Engineering: Faculty Publications

This study presents two novel theoretical models to elucidate frequency sensitive nuclear mechanisms in low-intensity ultrasound enhanced bioeffects. In contrast to the typical 1.5 MHz pulsed ultrasound regime, our group previously experimentally confirmed that ultrasound stimulation of anchored chondrocytes at resonant frequency maximized gene expression of load inducible genes which are regulatory markers for cellular response to external stimuli. However, ERK phosphorylation displayed no frequency dependency, suggesting that the biochemical mechanisms involved in enhanced gene expression is downstream of ERK phosphorylation. To elucidate such underlying mechanisms, this study presents a theoretical model of an anchored cell, representing an in vitro …

Design And Experimentation Of Cable-Driven Platform Stabilization And Control Systems, Matthew Newman

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

Agricultural researchers are constantly attempting to generate crops superior to those currently in use by the world. Whether this means creating crops with greater yield, crops that are more resilient to disease, or crops that can tolerate harsh environments with fewer failures, test plots of these experimental crops must be studied in real-world environments with minimal invasion to determine how they will perform in full-scale agricultural settings. To monitor these crops without interfering on their natural growth, a noninvasive sensor system has been implemented. This system, instituted by the College of Agricultural Sciences and Natural Resources at the University of …

Design And Experimentation Of Cable-Driven Platform Stabilization And Control Systems, Matthew Newman

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

Agricultural researchers are constantly attempting to generate crops superior to those currently in use by the world. Whether this means creating crops with greater yield, crops that are more resilient to disease, or crops that can tolerate harsh environments with fewer failures, test plots of these experimental crops must be studied in real-world environments with minimal invasion to determine how they will perform in full-scale agricultural settings. To monitor these crops without interfering on their natural growth, a noninvasive sensor system has been implemented. This system, instituted by the College of Agricultural Sciences and Natural Resources at the University of …

Development Of The End-Effector Of A Cable-Driven Parallel Manipulator For Automated Crop Sensing, Iman Salafian

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

A four cable-driven parallel manipulator (4CDPM), consisting of sophisticated spectrometers and imagers, is under development for use in acquiring phenotypic and environmental data over an acre-sized maize field. This thesis presents the design, controls, and testing of two sub-systems in a 4CDPM: a Center of Mass Balance System (CMBS) and a Drop-Down System (DDS).

One of the factors that influences stability is the center of mass (COM) position of the end effector. An offset in COM can cause a pendulum effect or an undesired tilt angle. A center of mass balancing system is presented in this thesis to minimize the …