Engineering Commons^™

Equipment Fragility Due To Shock Response, Christopher Y. Tuan

Department of Civil and Environmental Engineering: Faculty Publications

Because of its simplicity, the shock response spectrum has become widely used as a means of describing the shock responses and fragilities of structures and equipment. This paper focuses on the drawbacks of using the shock response spectrum for defining equipment shock tolerance. A cantilever beam with a tip mass was used to model a hypothetical piece of equipment subjected to strong ground motion such as that caused by an explosion. The exact solution from a detailed modal analysis shows that multiple modes of response were excited. Contributions from higher modes can be more predominant than that from the fundamental …

Numerical Simulations Of Dynamic Behavior Of Polyurea Toughened Steel Plates Under Impact Loading, Chien-Chung Chen, Daniel G. Linzell

Department of Civil and Environmental Engineering: Faculty Publications

The objective of the work discussed herein is to develop a nonlinear 3D finite element model to simulate dynamic behavior of polyurea toughened steel plates under impact loading. Experimental and numerical work related to model development are presented. Material properties are incorporated into numerical models to account for strain-rate effects on the dynamic behavior of polyurea and steel. One bare steel plate and four polyurea toughened steel plates were tested under impact loading using a pendulum impact device. Displacement time-history data from experimental work was used to validate the numerical models. Details on material model construction, finite element model development, …

Assessment Of Load Sharing Members In An Anti-Ram Bollard System, Scott Kinney, Daniel Linzell, Edward O'Hare

Department of Civil and Environmental Engineering: Faculty Publications

Due to the increased frequency, scale, and danger of malicious attacks carried out by Vehicle Borne Improvised Explosive Devices (VBIEDs), anti-ram bollards have become a key element in the protection of critical structures. This study focused on the evaluation of above grade load sharing members in a steel anti-ram bollard system in an attempt to develop efficient load sharing mechanisms that improve the structure’s ability to resist vehicle impacts, while concurrently remaining aesthetically pleasing to the general public. A computational assessment was completed using calibrated LS-DYNA finite element models to determine if effective load sharing member configurations and designs could …

Physiological And Transcriptional Memory In Guard Cells During Repetitive Dehydration Stress, Laetitia Virlouvet, Michael E. Fromm

Nebraska Center for Biotechnology: Faculty and Staff Publications

Arabidopsis plants subjected to a daily dehydration stress and watered recovery cycle display physiological and transcriptional stress memory. Previously stressed plants have stomatal apertures that remain partially closed during a watered recovery period, facilitating reduced transpiration during a subsequent dehydration stress. Guard cells (GCs) display transcriptional memory that is similar to that in leaf tissues for some genes, but display GC-specific transcriptional memory for other genes. The rate-limiting abscisic acid (ABA) biosynthetic genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) and ALDEHYDE OXIDASE 3 (AAO3) are expressed at much higher levels in GCs, particularly during the watered recovery interval, relative to their low …

The Pseudomonas Syringae Type Iii Effector Hopd1 Suppresses Effector-Triggered Immunity, Localizes To The Endoplasmic Reticulum, And Targets The Arabidopsis Transcription Factor Ntl9, Anna Block, Tania Y. Toruno, Christian G. Elowsky, Chi Zhang, Jens Steinbrenner, Jim Beynon, James R. Alfano

Nebraska Center for Biotechnology: Faculty and Staff Publications

Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and …

The Biophysical Link Between Climate, Water, And Vegetation In Bioenergy Agro-Ecosystems, Justin E. Bagley, Sarah C. Davis, Matei Georgesu, Mir Zaman Hussain, Jesse Miller, Stephen W. Nesbitt, Andy Vanloocke, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Land use change for bioenergy feedstocks is likely to intensify as energy demand rises simultaneously with increased pressure to minimize greenhouse gas emissions. Initial assessments of the impact of adopting bioenergy crops as a significant energy source have largely focused on the potential for bioenergy agroecosystems to provide global-scale climate regulating ecosystem services via biogeochemical processes. Such as those processes associated with carbon uptake, conversion, and storage that have the potential to reduce global greenhouse gas emissions (GHG). However, the expansion of bioenergy crops can also lead to direct biophysical impacts on climate through water regulating services. Perturbations of processes …

Divergence And Flow Direction As Indicators Of Subsurface Heterogeneity And Stage-Dependent Storage In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, A. K. Fox, Daniel E. Storm, Ronald B. Miller, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Assuming homogeneity in alluvial aquifers is convenient, but limits our ability to accurately predict stream-aquifer interactions. Research is needed on (i) identifying the presence of focused, as opposed to diffuse, groundwater discharge/recharge to streams and (ii) the magnitude and role of large-scale bank and transient storage in alluvial floodplains relative to changes in stream stage. The objective of this research was to document and quantify the effect of stage-dependent aquifer heterogeneity and bank storage relative to changes in stream stage using groundwater flow divergence and direction. Monitoring was performed in alluvial floodplains adjacent to the Barren Fork Creek and Honey …

Long-Term Activity Of Biohybrid Coatings Of Atrazine-Degrading Bacteria Pseudomonas Sp. Adp, Angela K. Pannier, T. Lehrer, M. Vogel, U. Soltmann, H. Bottcher, S. Tarre, M. Green, J. Raff, K. Pollmann

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The atrazine-degrading bacterial strain Pseudomonas sp. ADP was immobilized by the sol–gel process within thin silica layers coated onto water-retaining carrier materials (expanded clay pellets and scoria). The performance of the obtained biohybrid material has been investigated concerning long-term activity under non-growth conditions. Experiments were run in phosphate buffer containing atrazine (20 mg l^-1) as the sole source of carbon and nitrogen. Even after one year of consecutive batch tests, P. ADP immobilized onto expanded clay pellets showed a high atrazine degradation activity. In the course of long-term batch experiments, the average amount of removed atrazine was about …

Use Of Controller Area Network (Can) Data To Determine Field Efficiencies Of Agricultural Machinery, Santosh Pitla, N. Lin, Joe D. Luck, Scott A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Controller Area Network (CAN) bus is used on current agricultural equipment for in-vehicle communication among multiple microcontrollers. In this study, CAN data was collected from the tractor diagnostic port during three field operations: anhydrous ammonia (NH₃) application, field cultivation, and planting. Specifically, CAN messages corresponding to engine fuel use rate were filtered, decoded, and analyzed. High fuel use rates were recorded from the tractor when implements were engaged in the soil compared to when the implements were lifted out of the ground at the end of the passes or, when the tractor was turning and idling. Threshold fuel …

Meng 4200: Heat Transfer—A Peer Review Of Teaching Project Benchmark Portfolio, Yuebin Yu

UNL Faculty Course Portfolios

The main goal of attending this course review project is to improve my teaching performance of technical courses so that both the students and I can enjoy the mutual-learning process. Teaching to me is really rewarding. I believe teaching is an art, which can be continuously improved through learning from the peers, collecting and analyzing students' feedback and practice, regardless whether it is technical or practical. With good teaching, any course can be taught in a joyful manner. The specific objectives of the course portfolio include the follows: 1. Document the main materials for future refining through the documentation process …

Agen/Bsen 344: Biological And Environmental Transport Processes—A Peer Review Of Teaching Project Benchmark Portfolio, Shadi F. Othman

UNL Faculty Course Portfolios

The course I am providing a portfolio for is BSEN/AGEN 344 which is a required course for all our undergraduate students. The Department provides an assessment for the course to align itself with the ABET's Accreditation Process. I taught the course in Spring 2012 adapting a new Team Based Learning Approach. I have three main objective from my portfolio: (1) refine my methods in documenting the linkage between my course goals and assessment measures, (2) document the efficacy of team based learning approach, (3) refine team based learning approach for the current course and adapt the approach to future courses, …

Effect Of Laser-Assisted Resonant Excitation On The Growth Of Gan Films, H. Rabiee Golgir, Y. Gao, Y. S. Zhou, L. S. Fan, Kamran Keramatnejad, Yongfeng Lu

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

Gallium nitride (GaN) films were grown using laser-assisted metal organic chemical vapor deposition (LMOCVD). The vibrational mode (1084.63 cm^-1) of ammonia (NH₃) molecules was resonantly excited using a wavelength-tunable CO₂ laser at a laser wavelength of 9.219 μm due to its high absorption cross-section. Through wavelength-matched resonant excitation of the NH3 molecules, highly c-axis oriented GaN films were successfully deposited on sapphire (α-Al₂O₃) substrates at low temperatures (250 to 600^oC). The strong (0001) GaN peak in Xray diffraction spectra confirmed the good crystalline quality of GaN films. Additionally, the …

Fate Of Antimicrobials And Antimicrobial Resistance Genes In Simulated Swine Manure Storage, Stacey R. Joy, Xu Li, Daniel D. Snow, John Gilley, Bryan L. Woodbury, Shannon L. Bartelt-Hunt

School of Natural Resources: Faculty Publications

The behavior of three antibiotics (bacitracin, chlortetracycline, and tylosin) and two classes of antibiotic resistance genes (ARGs), tet and erm, were monitored in swine manure slurry under anaerobic conditions. First-order decay rates were determined for each antibiotic with half-lives ranging from1 day (chlortetracycline) to 10 days (tylosin). ARGs were monitored in the swine manure slurry, and losses of approximately 1 to 3 orders of magnitude in relative abundance were observed during the 40 day storage period. First-order degradation profiles were observed for chlortetracycline and its corresponding resistance genes, tet(X) and tet(Q). Tylosin was degraded to approximately 10% …

Enhanced Optical Bistability With Film-Coupled Plasmonic Nanocubes, Christos Argyropoulos, Cristian Ciraci, David R. Smith

Department of Electrical and Computer Engineering: Faculty Publications

Colloidally synthesized nanocubes strongly coupled to conducting films hold great promise for enhancing different nonlinear optical processes. They exhibit a robust and sensitive scattering response that can be easily controlled by their geometrical and material parameters. Strong local field enhancement is generated at the gap regions between the nanocubes and the metallic film. We show that strong optical bistability and all-optical switching behavior can be obtained by loading these nanogaps with Kerr nonlinear materials. Relatively low input intensities are required to obtain these nonlinear effects. The proposed design can lead to efficient, low-power, and ultrafast all-optical memories and scattering nanoswitches.

Temperature-Dependent Dielectric And Thermal Properties Of Whey Protein Gel And Mashed Potato, Jiajia Chen, Krishnamoorthy Pitchai, Sohan Birla, Ricardo Gonzalez, David Jones, Jeyamkondan Subbiah

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Temperature-dependent dielectric properties (dielectric constant and dielectric loss factor) and thermal properties (thermal conductivity and specific heat capacity) of whey protein gel and mashed potato were measured from -20°C to 100°C. A dielectric properties measurement system and a multipoint temperature calibration protocol were developed. The system consists of an impedance analyzer, a high-temperature coaxial cable, a high-temperature coaxial probe, a micro-climatic chamber and a metal sample holder. Calibrations at two temperatures (25°C and 85°C) were sufficient to accurately measure the dielectric properties of foods from frozen to hot temperatures. Both dielectric constant and dielectric loss factor rapidly increased from -20°C …

Multiplexed Fiber-Ring Laser Sensors For Ultrasonic Detection, Tongqing Liu, Lingling Hu, Ming Han

Department of Electrical and Computer Engineering: Faculty Publications

We propose and demonstrate a multiplexing method for ultrasonic sensors based on fiber Bragg gratings (FBGs) that are included inside the laser cavity of a fiber-ring laser. The multiplexing is achieved using add-drop filters to route the light signals, according to their wavelengths, into different optical paths, each of which contains a separate span of erbium-doped fiber (EDF) as the gain medium. Because a specific span of EDF only addresses a single wavelength channel, mode completion is avoided and the FBG ultrasonic sensors can be simultaneously demodulated. The proposed method is experimentally demonstrated using a two-channel system with two sensing …

Cmos Smart Camera With Focal Plane Neighborhood-Parallel Image Processing, Joseph A. Schmitz

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

A neighbhorhood-based smart camera architecture is designed and implemented in a 0.13 μm CMOS technology. Each 8 × 8 region of pixels contains a small processor with local memory, which are tiled to form a full-resolution camera. Each processor operates in parallel, enabling high-speed image processing suitable for tracking and recognition tasks. The architecture features the programming flexibility of designs us- ing chip-level and row-level processors while preserving the scalability of pixel-parallel processing elements. The neighborhood processors are implemented physically be- tween the pixel photodiodes, creating multiple design challenges that are discussed in detail.

Advisors: Sina Balkir and Michael W. …

Physical Design Of A Smart Camera With Integrated Digital Pixel Sensors Using A 0.13Μm 8-Layer Metal Cmos Process, Mahir K. Gharzai

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

The design of cameras has historically kept imagery and computational circuitry isolated in an attempt to maximize image quality by improving pixel pitch and routing density. Although this technique has worked in creating high density arrays of pixels for large resolution imagers, it has never been able to achieve high framerate computational operations.

A radical approach is introduced to solve this dilemma by creating compact, low- power pixel elements with built-in analog-to-digital converters that directly interface with digital logic. These pixels are capable of integrating alongside logic cells and to create an array of pixels inside the processor that can …

Narrow Grass Hedge Effects On The Transport Of Antimicrobials And Antimicrobial Resistance Genes Following Land Application Of Swine Slurry, Bhavneet Soni

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

The objective of this study was to determine the effects of manure amendment and narrow grass hedges on the fate and transport of antimicrobials and ARGs in runoff and in soil following the land application of swine manure slurry. Swine manure slurry was land applied to 0.75m wide by 4.0m long plots established on an Aksarben silty clay loam soil located in southeast Nebraska. The treatment factor manure amendment consisted of two levels: no manure application and manure application to meet the 3 year nitrogen (N) requirements for corn. The treatment factor of grass hedge was established for half of …

Drainage Structure Datasets And Effects On Lidar-Derived Surface Flow Modeling, Ruopu Li, Zhenghong Tang, Xu Li, Jessie Winter

School of Natural Resources: Faculty Publications

With extraordinary resolution and accuracy, Light Detection and Ranging (LiDAR)-derived digital elevation models (DEMs) have been increasingly used for watershed analyses and modeling by hydrologists, planners and engineers. Such high-accuracy DEMs have demonstrated their effectiveness in delineating watershed and drainage patterns at fine scales in low-relief terrains. However, these high-resolution datasets are usually only available as topographic DEMs rather than hydrologic DEMs, presenting greater land roughness that can affect natural flow accumulation. Specifically, locations of drainage structures such as road culverts and bridges were simulated as barriers to the passage of drainage. This paper proposed a geospatial method for producing …

Nd–Fe–B Nanoparticles Through Surfactant Assisted Mechanical Milling And Alloy Design, Jordann M. Bornhoft

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

Surfactant-assisted mechanical milling has been used to produce discrete nanoparticles of both Nd-Fe-B and Sm-Co amenable for bottom-up production of nanostructured or nanocomposite permanent magnets. However, in Nd-Fe-B the comminution of the material proceeds by transgranular fracture, which influences both the morphology of the nanoparticles and the magnetic properties. This paper utilizes alloy design to alter the fracture behavior from transgranular fracture to intergranular fracture. Nd-rich Nd₂Fe₁₄B alloys were produced by melt spinning in an overquenched state. The melt spun ribbons were annealed at 700°C and 800°C to ensure complete crystallization and to form different grain …

Intensity-Demodulated Fiber-Ring Laser Sensor System For Acoustic Emission Detection, Ming Han, Tongqing Liu, Lingling Hu, Qi Zhang

Department of Electrical and Computer Engineering: Faculty Publications

We theoretically and experimentally demonstrate a fiber-optic ultrasonic sensor system based on a fiber-ring laser whose cavity consisting of a regular fiber Bragg grating (FBG) and a tunable optical band-pass filter (TOBPF). The FBG is the sensing element and the TOBPF is used to set the lasing wavelength at a point on the spectral slope of the FBG. The ultrasonic signal is detected by the variations of the laser output intensity in response to the cold-cavity loss modulations from the ultrasonicallyinduced FBG spectral shift. The system demonstrated here has a simple structure and low cost, making it attractive for acoustic …

Acuta Enews December 20132 Vol. 42, No. 12

ACUTA Newsletters

In this Issue...

1 Board Approves Slate of Nominees

1 A Gift from ACUTA to You!

2 Nominate Now for Ruth A, Michalecki Leadership Award i

3 What's on Your Desk?

4 From the Listserv

6 RF Video Distribution Solution for the University of the South

7 Info Links

8 Board Report

9 Welcome New Members

9 Check It Out

Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason G. Vogeler

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Polycarbonate (PC) is a tough, transparent engineering thermoplastic. Its impact strength and ability undergo large plastic deformations without shatter make PC an ideal protective material for impact-resilient eyewear, aircraft windows and transparent armor. A good understanding of the response of this material to large deformations at high strain rates is critical for its utilization in these applications. To this end, a striker-less Kolsky bar device is employed in this work for the needed material characterization. The apparatus allow impulsive torsion and/or compression loadings with pulse durations sufficiently long for the plastic flow behavior to develop fully. Three new testing techniques …

A Study On Countermeasures Against Steganography: An Active Warden Approach, Qilin Qi

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

Digital steganography is a method used for hiding information in digital images. It can be used for secure communication. There have been many robust digital steganography methods invented in recent decades. The steganographic message can be inserted in multimedia cover signal such as audio, image and video. However, this technique also may be used by malicious users to transmit dangerous information through the Internet beyond the control of security agencies. How to detect and/or block potentially dangerous information transmission on the Internet through billions of multimedia files while not affecting innocent multimedia communications becomes a challenging problem. Existing steganalysis methods …

Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason Gerald Vogeler

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Polycarbonate (PC) is a tough, transparent engineering thermoplastic. Its impact strength and ability undergo large plastic deformations without shatter make PC an ideal protective material for impact-resilient eyewear, aircraft windows and transparent armor. A good understanding of the response of this material to large deformations at high strain rates is critical for its utilization in these applications. To this end, a striker-less Kolsky bar device is employed in this work for the needed material characterization. The apparatus allow impulsive torsion and/or compression loadings with pulse durations sufficiently long for the plastic flow behavior to develop fully. Three new testing techniques …

Fea Estimation And Experimental Validation Of Solid Rotor And Magnet Eddy Current Loss In Single-Sided Axial Flux Permanent Magnet Machines, Xu Yang

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

The rotor and magnet loss in single-sided axial ux permanent magnet (AFPM) machines with non-overlapped windings is studied in this dissertation. Finite element analysis (FEA) estimations of the loss are carried out using both 2D and 3D modeling. The rotor and magnet losses are determined separately for stator slot passing and MMF space harmonics from currents in the stator. The segregation of loss between the solid rotor plate and the magnet is addressed. The eddy current loss reduction by magnet segmentation is discussed as well. Two prototype 24 slot/22 pole single-sided AFPMs, fabricated with both single layer (SL) and double …

Effects Of Time Varying Background Noise Conditions On Human Perception And Performance, Andrew H. Hathaway

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

This thesis was designed to study the effects of changing noise conditions on human perception and performance. In two phases, participants were exposed to a number of noise conditions and their performance on an arithmetic task involving short-term memory was monitored and their subjective perception of noise conditions was collected via questionnaires.

In the first phase, participants were tested while being subjected to RC-29(H) and RC-47(RV) conditions created by broadband noise fluctuating on different time intervals, resembling the changing noise conditions potentially found in modern HVAC systems. These intervals varied from two minutes to ten minutes. Results show a significant …

Passive Stormwater Samplers For Sampling Highway Runoff From Bmps: Feasibility Studies, Tian C. Zhang, John S. Stansbury, Massom Moussavi

Nebraska Department of Transportation: Research Reports

No abstract provided.

Fertilizer Effects On Attaining Vegetation Requirements, Walter H. Schacht, Carol Wienhold

Nebraska Department of Transportation: Research Reports

No abstract provided.