Engineering Commons^™

Thermosensitive Gel Containing Cellulose Acetate Phthalate-Efavirenz Combination Nanoparticles For Prevention Of Hiv-1 Infection, Abhijit A. Date, Annemarie Shibata, Emily Mcmullen, Krista La Bruzzo, Patrick Bruck, Michael Belshan, You Zhou, Christopher J. Destache

Nebraska Center for Biotechnology: Faculty and Staff Publications

The objective of this investigation was to develop and evaluate a nano-microbicide containing a combination of cellulose acetate phthalate (HIV-1 entry inhibitor) and efavirenz (anti-HIV agent) for HIV prophylaxis. Cellulose acetate phthalate-efavirenz combination nanoparticles (CAP-EFV-NPs) were fabricated by the nanoprecipitation method and were characterized for particle size, zeta potential and encapsulation efficiency of efavirenz. CAP-EFV-NPs were incorporated into a thermosensitive gel (CAP-EFV-NP-Gel). CAP-EFV-NPs, CAP-EFV-NP-Gel and efavirenz solution were evaluated for cytotoxicity to HeLa cells and for in vitro short-term (1-day) and long-term (3-day) prophylaxis against HIV-1 infection in TZM-bl cells. CAP-EFV-NPs had size < 100 nm, negative surface charge and encapsulation efficiency of efavirenz was > 98%. CAP-EFV-NPs and CAP-EFV-NP-Gel were significantly less …

Enhanced Pool-Boiling Heat Transfer And Critical Heat Flux On Femtosecond Laser Processed Stainless Steel Surfaces, Cory M. Kruse, Troy Anderson, Chris Wilson, Craig Zuhlke, Dennis Alexander, George Gogos, Sidy Ndao

Department of Mechanical and Materials Engineering: Faculty Publications

In this paper, we present an experimental investigation of pool boiling heat transfer on multiscale (micro/nano) functionalized metallic surfaces. Heat transfer enhancement in metallic surfaces is very important for large scale high heat flux applications like in the nuclear power industry. The multiscale structures were fabricated via a femtosecond laser surface process (FLSP) technique, which forms self-organized mound-like microstructures covered by layers of nanoparticles. Using a pool boiling experimental setup with deionized water as the working fluid, both the heat transfer coefficients and critical heat flux were investigated. A polished reference sample was found to have a critical heat flux …

Underwater Sound Transmission Through Arrays Of Disk Cavities In A Soft Elastic Medium, David C. Calvo, Abel L. Thangawng, Christopher N. Layman Jr., Riccardo Casalini, Shadi F. Othman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Scattering from a cavity in a soft elastic medium, such as silicone rubber, resembles scattering from an underwater bubble in that low-frequency monopole resonance is obtainable in both cases. Arrays of cavities can therefore be used to reduce underwater sound transmission using thin layers and low void fractions. This article examines the role of cavity shape by microfabricating arrays of disk-shaped air cavities into single and multiple layers of polydimethylsiloxane. Comparison is made with the case of equivalent volume cylinders which approximate spheres. Measurements of ultrasonic underwater sound transmission are compared with finite element modeling predictions. The disks provide a …

Influence Of Resonant And Non-Resonant Vibrational Excitation Of Ammonia Molecules In Gallium Nitride Synthesis, Hossein Rabiee Golgir, Yunshen Zhou, Kamran Keramatnejad, Yongfeng Lu

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

Attempts on the selective promotion of gallium nitride (GaN) growth were investigated by deploying laserassisted vibrational excitation of reactant molecules, which deposits energy selectively into specific molecules and activate the molecules towards the selected reaction pathways. Laser-assisted metal organic chemical vapor deposition (LMOCVD) of GaN was studied using a wavelength-tunable CO2 laser. The NH-wagging modes (υ2) of ammonia (NH3) precursor molecules are strongly infrared active and perfectly match the emission line of the CO2 laser at 9.219, 10.350, and 10.719 μm. On- and off-resonance excitations of molecules were performed via tuning the incident laser wavelengths at on-resonant wavelength 9.219 μm …

Size Effects In Human Visual Inspection For Micro/Meso Scale Parts, Sri Harsha Kavuri

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

Visual inspection has been a major method of quality control in conventional manufacturing processes for the last fifty years. Utilizing trained human inspectors to perform this visual inspection has been the most effective means of maintaining quality control. Extensive research has been performed to understand the factors that influence the human inspection process.

In the recent years, there has been a significant emphasis on manufacturing at the smaller end of the size-spectrum such as Micro and Meso scale manufacturing. Quality control at becomes a challenging task due to the extremely small sizes. Several automated visual inspection techniques have been proposed …

Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza

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

Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumptions of a uniform track bed and a homogeneous rail. However the spatial variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerate the fatigue process. The research described in this dissertation is focused on …

Broadband In Nebraska: Current Landscape And Recommendations, Nebraska Information Technology Commission, Nebraska Broadband Initiative, Nebraska Public Service Commission, University Of Nebraska-Lincoln, Nitc Community Council, Nebraska Department Of Economic Development, Aim

Rural Futures Institute: Publications

N ebraska’s broadband vision is that residents, businesses, government entities, commu-nity partners, and visitors have access to affordable broadband service and have the necessary skills to effectively utilize broadband technologies.

Objectives

To increase economic development opportunities, create good-paying jobs, at-tract and retain population, overcome the barriers of distance, and enhance qual-ity of life in Nebraska by stimulating the continuing deployment of broadband technologies which meet the need for increasing connection speeds.

To increase digital literacy and the widespread adoption of broadband technolo-gies in business, agriculture, health care, education, government and by individu-al Nebraskans.

Goals

The following goals and targets help …

Laparoscopic Devices And Methods Of Using, M. Susan Hallbeck, Jakeb Riggle, Adam De Laveaga, Jake Kaufman

Department of Mechanical and Materials Engineering: Faculty Publications

A number of improvements to laparoscopic devices are described herein, primarily to improve the ergonomic functionality of the devices. For example, an articulating rod system is described, a gripping mechanism is described, and an end effector is described

Coordinated Control And Estimation Of Multiagent Systems With Engineering Applications, Housheng Su, Michael Z.Q. Chen, Qing Hui, Wei Zhang, Fanglai Zhu

Department of Electrical and Computer Engineering: Faculty Publications

Recently, coordinated control and estimation problems have attracted a great deal of attention in different fields especially in biology, physics, computer science, and control engineering. Coordinated control and estimation problems have prominent characteristics of distributed control, local interaction, and self-organization. Research on multiagent coordinated control and estimation problems not only helps better understand the mechanisms of natural collective phenomena but also benefits the applications of cyberphysical systems.

This special issue focuses on theoretical and technological achievements in cooperative multiagent Systems. It contains twenty-six papers, the contents of which are summarized below.

Influence Of The Temperature On Flow-Induced Crystallization Of Isotactic Polypropylene And Propylene–Ethylene Random Copolymer, Hugo Boitout

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

When flow is applied on a semi-crystalline polymer melt, it can greatly impact how it crystallizes its final properties. Therefore, it is crucial to understand the basic mechanism of flow induced crystallization (FIC). Only then will it be possible to predict final properties from the type of resin and processing conditions. Polypropylene is one of the most widely used polymers. Its processing generally involves subjecting the melt to intense flow fields, so FIC commonly occurs.

This study investigates the influence of temperature of shear and crystallization on the FIC behavior of isotactic polypropylene (iPP). Temperature is one of the main …

Evaluation Of The Mass Transfer Effect Of The Stalk Contraction–Relaxation Cycle Of Vorticella Convallaria, Jiazhong Zhou

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

Vorticella convallaria is a genus of protozoa living in fresh water. It has a bell-shaped zooid equipped with adoral ciliary bands and a contractile stalk tethering the zooid to a substrate. Vorticella is regarded as a biological spring because its contractile stalk can pull the zooid towards the substrate at a remarkably high speed and then relaxes to its extended state much more slowly. However, reasons for Vorticella’s stalk contraction are still unknown. It is presumed that the flow field induced by the contraction-relaxation cycle of Vorticella would augment mass transfer effect near the substrate. We investigated this hypothesis …

Nebraska Center For Educational Science Outreach: A Clearinghouse Meeting People At Their Level To Make Stem Outreach Easier, Kiyomi D. Deards

University of Nebraska-Lincoln Libraries: Presentations

Identify key partners and stakeholders.

Conduct a STEM outreach needs assessment.

Develop a long-term plan.

1. How can faculty & staff support your STEM outreach?

2. How can you help faculty & staff with STEM outreach?

Single- And Dual-Porosity Calibration And Long-Term Modeling Of Highly Conductive Floodplain Soils In The Ozark Ecoregion, Ryan P. Freiberger

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

Phosphorus (P) is a critical nutrient for agriculture, but is also responsible for surface water enrichment that leads to algal growth. While P loading to surface waters has traditionally been thought to occur from surface runoff, contributions from subsurface transport can also be significant. Subsurface transport through gravelly soils in the Ozark ecoregion can have a significant, yet poorly-documented effect on P movement to groundwater.

Long-term P modeling was performed in HYDRUS-1D and 2D using data collected from short-term plot experiments featuring gravelly soils. Seven model levels were developed to illustrate a wide variety of laboratory and field conditions. Calibration …

Control Of Responses Of Smart Plate Structures Under Non-Stationary Random Excitations, Xiaojian Yang

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

This thesis is concerned with an investigation of the control of responses of plate structures with piezoelectric layers and under complicated excitations modeled as a non-stationary random process. The plate structures and piezoelectric layers are both discretized by the mixed formulation finite element method (FEM).

The investigation consists of three parts. The first part is a literature survey and theoretical development. The second part is the eigenvalue solution and computation of uncontrolled response statistics of laminated plate structures under nonstationary random excitations. The final part is the introduction and application of the stochastic central difference (SCD) method that was presented …

Heat Transfer Enhancement And Applications Of Femtosecond Laser Processed Metallic Surfaces, Corey M. Kruse

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

In the present work, functionalized 304 stainless steel metallic surfaces were created with the use of a Femtosecond Laser Surface Processing (FLSP) technique. The laser processing technique produces self-organized micro/nanostructures on the surface. The heat transfer performance of various FLSP functionalized surfaces were characterized through pool boiling and Leidenfrost experiments. Enhancement in both the nucleate and film boiling heat transfer were observed through an increase of the critical heat flux and heat transfer coefficient as well as shifts in the Leidenfrost temperature respectively. For both experiments, a polished reference sample was used as a baseline line to compare against the …

Effects Of Operating Conditions On Removal Of Trace-Amount Testosterone By Nitrocellulose Filter Membrane, Ying Liang

Department of Environmental Engineering: Theses and Other Student Research

Hormone can be removed by membrane filtration via membrane interception, sorption and diffusion. However, the effects of operating conditions of membrane filtration on hormone removal have not been evaluated systematically. In this study, the removal of testosterone by nitrocellulose membranes under different operating conditions (e.g., initial testosterone concentrations, sample volumes, flow rates and membrane pore sizes) was investigated. ¹⁴C-labeled testosterone was used as a tracer to determine the removal of testosterone in the filtration process, and a hydrodynamic model was used to determine dispersion coefficient (D) associated with the operating conditions and radius of hormone molecule. Results indicate that …

A Performance Study Of Genetic Algorithm-Assisted Beamforming In Distributed Cognitive Radio Networks, Andrew Minturn

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

Cognitive Radio (CR) is a technology that has gained much interest recently due to the increasing scarcity of the radio frequency spectrum. Large portions of the radio frequency spectrum are licensed to users who then have exclusive access to the bandwidth, and unlicensed bands can be a challenge to use due to interference from unlicensed users. Despite the seeming scarcity, tests of bands allocated by the Federal Communications Committee (FCC) to licensed and unlicensed user have shown that many are underutilized and often unoccupied by the user to whom they are licensed. CR aims to exploit this unused spectrum and …

A Study On Resource Efficient Digital Multimedia Security Measures In Mobile Devices, Prabhat Dahal

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

Advanced image and video processing abilities in smart phones and digital cameras make them popular means to capture multimedia. In addition, the integration of internet into such devices users seek to capture and easily share multimedia right from their smartphone while most steganography techniques are computer based. Hence, it is of utmost importance that the multimedia be processed for steganography right within the devices for multimedia authentication.

In this thesis, we first implement steganography into mobile smart devices that can capture multimedia. For devices such as smart phones, we propose a method to hide payload bits within video frames. The …

Feedlot Manure Management Considerations Including Anaerobic Digestion Potential And Mineral Retention, Andrea K. Watson

Department of Animal Science: Dissertations, Theses, and Student Research

Three anaerobic digestion trials were conducted to evaluate methane production from feedlot manure. As organic matter content of manure decreased, degradation of manure and methane production also linearly decreased (P ≤ 0.02). Quality, or organic matter content of manure, had a greater impact on anaerobic digestion than diet (with and without distillers grains) fed to cattle. Minerals are concentrated in effluent removed from anaerobic digesters.

Knowing mineral retention within cattle allows for more accurate calculation of mineral excretion in manure. Three serial slaughter trials measured mineral retention in growing and finishing cattle. During a growing phase, beef cattle gaining …

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A Comparative Study Of Generalized Arc-Consistency Algorithms, Olufikayo S. Adetunji

School of Computing: Dissertations, Theses, and Student Research

In this thesis, we study several algorithms for enforcing Generalized Arc­-Consistency (GAC), which is the most popular consistency property for solving Constraint Satisfaction Problems (CSPs) with backtrack search. The popularity of such algorithms stems from their relative low cost and effectiveness in improving the performance of search. Virtually all commercial and public- domain constraint solvers include some implementation of a generic GAC algorithm. In recent years, several algorithms for enforcing GAC have been proposed in the literature that relies on increasingly complex data structures and mechanisms to improve performance. In this thesis, we study, assess, and compare a basic algorithm …

Identification Of Groundwater Sources For Municipal Wells Using Geochemical Data On The Platte Alluvial Aquifer And Underlying Limestone At The Lincoln Water Well Field Near Ashland Nebraska, Juanita Cruz Torres

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Alluvial aquifer systems where pumping of municipal wells induces recharge from the adjacent river are the primary source of water for many cities. The city of Lincoln, NE has a primary water source in an alluvial aquifer adjacent to the Platte River. The Lincoln Water System manages the stream/aquifer system by using integrated models for a better understanding during periods of high stress such as a drought. The integrated models set the limestone aquifer as an impermeable boundary to understand the alluvial aquifer system without having a secondary water source. The limestone aquifer is permeable and the purpose of this …

Increased Span Length For The Mgs Long-Span Guardrail System, Nicholas A. Weiland, Ronald K. Faller, Robert W. Bielenberg, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

A Highly Adaptive And Cost Effective Second Generation Incubator (Sgi) Towards Educational, Research And Clinical Processes, Yassir H. Al-Sayagh

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

Today´s rising demand for more reliable and affordable alternatives to organ transplant has led to a growing market for in vitro tissue culture systems. The main objective of tissue engineering as a whole is to employ human tissue equivalents for commercial use. The state-of-the-art processes for producing these so called tissue models are still very expensive, difficult to produce and time-consuming.

To engineer tissues, in vitro, a three-dimensional support structure commonly termed scaffold is needed. Stem cells are then added to the scaffold. In order for tissue to materialize, the scaffold and the cells must be incubated (cultured) at a …

Long-Acting Antituberculous Therapeutic Nanoparticles Target Macrophage Endosomes, Benson J. Edagwa, Dongwei Guo, Pavan Puligujja, Han Chen, Joellyn Mcmillan, Xinming Liu, Howard Gendelman, Prabagaran Narayanasamy

Nebraska Center for Biotechnology: Faculty and Staff Publications

Eradication of Mycobacterium tuberculosis (MTB) infection requires daily administration of combinations of rifampin (RIF), isoniazid [isonicotinylhydrazine (INH)], pyrazinamide, and ethambutol, among other drug therapies. To facilitate and optimize MTB therapeutic selections, a mononuclear phagocyte (MP; monocyte, macrophage, and dendritic cell)-targeted drug delivery strategy was developed. Long-acting nanoformulations of RIF and an INH derivative, pentenyl- INH (INHP), were prepared, and their physicochemical properties were evaluated. This included the evaluation of MP particle uptake and retention, cell viability, and antimicrobial efficacy. Drug levels reached 6 μg/106 cells in human monocyte-derived macrophages (MDMs) for nanoparticle treatments compared with 0.1 μg/106 cells for native …

Application Of Femtosecond Laser Surface Processed Electrodes In Electrolysis Of Water, Christopher K. Wilson

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

Femtosecond laser surface processing (FLSP) is a machining technique used to develop functionalized surfaces consisting of micro and nano-scale features. Metal electrodes processed using this technique can be used in water electrolysis to facilitate more efficient hydrogen and oxygen gas production. This thesis explores the electrochemical behavior of femtosecond laser processed 316SS electrodes in water electrolysis. The multi-scale surface structure size and separation were controlled through laser fluence and incident laser pulse count. The electrodes were studied in a three electrode electrolysis cell containing a 3M KOH(aq) electrolyte, FLSP 316SS working electrode, 316SS counter electrode, and Hg/HgO reference electrode. Through …

Gis-Based Route Risk Assessment Of Hazardous Material Transport, Myungwoo Lee

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

The transportation of hazardous materials keeps increasing across the United States due to the growing consumption of goods and rising need for manufactured materials. Furthermore, concerns are mounting over the safe surface transportation of hazardous materials. Highways and rails are the most common modes of transport for hazardous materials, although the risk posed from highway transport of hazardous materials may be higher due to the fact that highways are public while rails are mostly private. The majority of hazardous material cargo is carried on the highway network by trucks. Due to possible adverse effects on human and animal populations in …

Low Molecular Weight Glucosamine/L-Lactide Copolymers As Potential Carriers For The Development Of A Sustained Rifampicin Release System: Mycobacterium Smegmatis As A Tuberculosis Model, Jorge Ragusa

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Tuberculosis, a highly contagious disease, ranks as the second leading cause of death from an infectious disease, and remains a major global health problem. In 2013, 9 million new cases were diagnosed and 1.5 million people died worldwide from tuberculosis. This dissertation aims at developing a new, ultrafine particle-based efficient antibiotic delivery system for the treatment of tuberculosis. The carrier material to make the rifampicin (RIF)-loaded particles is a low molecular weight star-shaped polymer produced from glucosamine (molecular core building unit) and L-lactide (GluN-LLA). Stable particles with a very high 50% drug loading capacity were made via electrohydrodynamic atomization. Prolonged …

Microstructure And Magnetic Behavior Studies Of Processing-Controlled And Composition-Modified Fe–Ni And Mn–Al Alloys, Yunlong Geng

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

L1₀-type (Space group P4/mmm) magnetic compounds, including FeNi and MnAl, possess promising technical magnetic properties of both high magnetization and large magnetocrystalline anisotropy energy, and thus offer potential in replacing rare earth permanent magnets in some applications.

In equiatomic Fe-Ni, the disorder-order transformation from fcc structure to the L1₀ structure is a diffusional transformation, but is inhibited by the low ordering temperature. The transformation could be enhanced through the creation of vacancies. Thus, mechanical alloying was employed to generate more open-volume defects. A decrease in grain size and concomitant increase in grain boundary area resulted from …

Two-Dimensional Scalar Differential Equations For Transversely Varying Thickness Modes In Piezoelectric Plates And Applications In Acoustic Wave Resonator Sensors, Huijing He

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

Generalizations are made for three types of well-known and widely used twodimensional scalar differential equations in the literature describing transversely varying thickness modes in piezoelectric plate resonators. They are for singly-rotated quartz plates, doubly-rotated quartz plates, and plates of crystals of class 6mm with the c-axis along the plate thickness, respectively. The purpose of the generalizations is to include the effects of surface mechanical loads such as mass layers or fluids for resonator -based acoustic wave sensor applications. Surface acoustic impedance is introduced to take into account various surface loads in a general manner for time-harmonic motions. Both unelectroded and …