Engineering Commons^™

Developing Equivalent Second Order System Models And Robust Controls For Servo-Drive Related Systems, Christopher Hoyt

Electrical Engineering Undergraduate Honors Theses

Numerous industrial and other plant processes today represent systems in which a motor supplies torque to a drive disk, which in turn through a pulley system drives a larger load. Developing models for these complex systems can become time consuming and expensive. A simple second order system approximation can be developed for these systems under certain system conditions which can greatly reduce the complexity of controlling and modeling the system. A second order feed-forward notch controller can then be introduced to the system which greatly improves performance. The results of this proposed method of approximating complex servo-drive systems show that …

Rainwater Harvesting Pilot Project Report, Liam Mccarton, Sean O'Hogain, Anna Reid, Niamh Mcintyre, Jenny Pender

Reports

The rainwater harvesting pilot project was commissioned by the National Rural Water Monitoring Committee in 2005 to assess the feasibility of supplementing treated mains water used for non-potable purposes. The project involved the design, installation, commissioning and monitoring of rainwater harvesting facilities in a rural housing development in County Carlow and in a 250-acre livestock farm in County Meath. Construction was carried out between 2005-2007.

PagetʼS Disease (Osteitis Deformans) In Archaeological Remains: A Radiographic Differential, Andrew D. Wade, Gregory J. Garvin, David W. Holdsworth

Anthropology Presentations

Paget’s disease of bone is a metabolic bone disease of unknown etiology and is the most likely disease to cause secondary bone cancer; a prevalence that increases with age[1]. With the increasing age of modern populations, the importance of better understanding this disease will likewise increase. While in vivo tests for the disease cannot be performed in skeletal samples, radiographic views of archaeological remains can provide insight into the origins and natural history of the disease.

Temperature Induced Instabilities In Macro-Bend Fiber Based Wavelength Measurement Systems, Ginu Rajan, Yuliya Semenova, Pengfei Wang, Gerald Farrell

Articles

An investigation of temperature-induced instabilities in a wavelength measurement system based on macro-bend fiber filter used in the ratiometric scheme are presented. Two wavelength measurement systems based on macro-bend fiber, a standard low bend loss single-mode fiber filter based system and a high bend loss fiber filter based system are considered. In the case of a low bend loss fiber filter based system, the oscillatory variation in the ratio response with temperature and the difference in the temperature-induced ratio variation at different wavelengths makes the temperature corrected calibration of the system unfeasible, which is essential for precise wavelength measurements. The …

Design, Construction, And Testing Of A New Class Of Mobile Robots, Ivan Siles

All Theses

This thesis introduces a novel mobile robot design concept aimed at exploration of subterranean spaces. The key innovation is the combination of highly maneuverable body elements with wheel/leg elements (Whegs). This combination offers performance not possible with conventional 'monolithic' wheeled or tracked mobile robots, or with current robot snakes. The thesis covers four design iterations of the concept, concentrating on describing the overall design process and results from field tests. Additionally a kinematic analysis of the fourth prototype and implications for future designs is presented.

Interaction Of Soil And Seepage Barrier Cracks Under Seepage Flow, Justin Whitmer

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Seepage barriers are commonly installed in earthen dams and levees all over the world and consist of slurry walls, concrete walls, jet grouted walls, secant pile walls, sheet pile walls, and deep soil mixed walls. The purpose of the barrier is to reduce the amount of flow and seepage through the embankment and the foundation of the dam or levee. When seepage barriers were first being used it was under the impression that barriers would be a permanent mitigation of seepage problems. However, in prior research (Rice, 2007) it is mentioned that there are several cases where the seepage barriers …

Warning! Engineers In Training: Introducing Middle School Students To Industrial Engineering, Its Usefulness, And Its Applications, M. Grubb, A. Berger, D. Browning, M. Mayorga, Laine Mears

Publications

The McCants Middle School Pre-engineering class is designed to teach engineering skills to students with a predisposition for and interest in math and science. This team’s initiative is to use Industrial Engineering tools to enhance the existing pre-engineering course curriculum. The purpose of this study is to make middle school students better aware of an engineer’s thought process as it pertains to effectively planning and working on projects, and to measure the impact of our influence. Through this study, we want to improve the overall quality of the student’s projects and ultimately increase the retention and quantity of students interested …

Towards Dynamical Systems Approach To Fuzzy Clustering, Vladik Kreinovich, Olga Kosheleva

Departmental Technical Reports (CS)

In many application areas, there is a need for clustering, and there is a need to take fuzzy uncertainty into account when clustering. Most existing fuzzy clustering techniques are based on the idea that an object belongs to a certain cluster if this object is close to a typical object from this cluster. In some application areas, however, this idea does not work well. One example of such application is clustering in education that is used to convert a detailed number grade into a letter grade.

In such application, it is more appropriate to use clustering techniques which are based …

Dc-Ac Cascaded H-Bridge Multilevel Boost Inverter With No Inductors For Electric/Hybrid Electric Vehicle Applications, Zhong Du, Burak Ozpineci, Leon M. Tolbert, John N. Chiasson

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc–dc boost converter to boost the battery voltage for a traditional three-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. A cascaded H-bridge multilevel boost inverter design for EV and HEV applications implemented without the use of inductors is proposed in this paper. Traditionally, each H-bridge needs a dc power supply. The …

Magnetically Anchored "Reduced Trocar" Laparoscopy: Evolution Of Surgical Robotics, Richard Bergs

Bioengineering Theses - Archive

Laparoscopic surgery has become increasingly popular over the last few years due to its benefits; lower morbidity, less perceived pain, better cosmesis results, and less hospital time. For the surgeon however, there are fundamental issues that can make a laparoscopic procedure more difficult than simple open surgery; loss of tactile feel, limited working envelope, high demand for hand-eye coordination, and one trocar-port required for each tool. A revolutionary concept of using magnetics to support tooling across the abdominal wall was conceived by Dr. Jeffrey Cadeddu and his colleagues at the University of Texas Southwestern Medical Center. Collectively referred to as …

A Study In The Information Content, Consistency, And Expressive Power Of Function Structures In Mechanical Design, Chiradeep Sen

All Theses

In engineering design research, function structures are used to represent the intended functionality of technical artifacts. Function structures are graph-based representations where the nodes are functions, or actions, and the edges are flows, or objects of those actions. For the consistent description of artifact functionality, multiple controlled vocabularies have been developed in previous research. The Functional Basis is one such vocabulary that provides for a set of verbs and a set of nouns, organized in the three-level hierarchy. This vocabulary is extensively studied in design research. Two major application of this vocabulary are the Design Repository, which is a web-base …

Rheological, Thermal And Processing Studies Of Perfluorocyclobutyl (Pfcb) Polymers, Erick Vasquez

All Theses

Polymeric materials are of interest to the fiber optics industry as glass–silica fibers are prone to fracture. However, the thermal resistance properties of current polymeric materials have limited their use in some optical applications including high performance lasers and high speed telecommunication systems. Therefore, it is of interest to develop new polymer materials and systems with enhanced thermal properties and processability for application in optics. This work focuses on the novel Perfluorocyclobutyl (PFCB) polymer systems. PFCB polymers possess characteristics that make them suitable for optics applications including: a low refractive index, high thermal stability and high chemical resistance. However, little …

Resonant Oscillation Of Misch-Metal Atoms In Filled Skutterudites, Yaguo Wang, Xianfan Xu, Jihui Yang

Birck and NCN Publications

We investigate vibrational behaviors in misch-metal filled antimony skutterudites in the time domain. At higher filling ratios of guest atoms, the vibration frequency approaches that of the cage structure and the amplitude becomes stronger. Furthermore, the reduction of lattice thermal conductivity over a wide temperature range can be explained using the measured resonant vibrational frequency. These findings reveal that the reduction of the lattice thermal conductivity is a result of scattering of acoustic phonons due to the resonant interaction between guest atoms and lattice phonons.

Real Space First-Principles Derived Semiempirical Pseudopotentials Applied To Tunneling Magnetoresistance, Kirk Huw Bevan, Tony Low, H Guo

Birck and NCN Publications

We present a real space density functional theory localized basis set semiempirical pseudopotential (SEP) approach. The method is applied to iron and magnesium oxide, where bulk SEP and local spin density approximation band structure calculations are shown to agree within approximately 0.1 eV. Subsequently we investigate the qualitative transferability of bulk derived SEPs to Fe/MgO/Fe tunnel junctions. We find that the SEP method is particularly well suited to address the tight binding transferability problem because the transferability error at the interface can be characterized not only in orbital space (via the interface local density of states) but also in real …

Development Of A New Lagrangian Float For Studying Coastal Marine Ecosystems, Alex Schwithal, Chris Roman

Graduate School of Oceanography Faculty Publications

This paper presents an overview and initial testing results for a shallow water Lagrangian float designed to operate in coastal settings. The presented effort addresses the two main characteristics of the shallow coastal environment that preclude the direct of use of many successfully deep water floats, namely the higher variation of water densities near the coast compared with the open ocean and the highly varied bathymetry. Our idea is to develop a high capacity dynamic auto-ballasting system that is able to compensate for the expected seawater density variation over a broad range of water temperatures and salinities while using measurements …

Rarefied Gas Flow In Microtubes At Different Inlet-Outlet Pressure Ratios, Z Yang, Suresh Garimella

Birck and NCN Publications

A model is developed for rarefied gas flow in long microtubes with different inlet-outlet pressure ratios at low Mach numbers. The model accounts for significant changes in Knudsen number along the length of the tube and is therefore applicable to gas flow in long tubes encountering different flow regimes along the flow length. Predictions from the model show good agreement with experimental measurements of mass flow rate, pressure drop, and inferred streamwise pressure distribution obtained under different flow conditions and offer a better match with experiments than do those from a conventional slip flow model.

Testing And Monitoring Concrete Using Novel Methods For Predicting Their Long Term Behaviour, Sreejith Nanukuttan, Lulu Basheer, Muhammed Basheer, Niall Holmes, John Mccarter, Malcolm Chrisp, Gerry Starrs

Conference papers

It is widely recognised that durability of concrete depends on its transport properties, viz. absorption, diffusion and permeability. As concrete cover provides the first line of defence against the ingress of many deleterious substances into the concrete, a measure of its transport properties is vital in assessing its long term performance in the given exposure condition. In new structures the rate of ingress of the deleterious substances could be monitored using array of electrical sensors which are embedded in the cover concrete. For structures which are currently in service, two in situ permeability apparatuses, viz. Autoclam Permeability System (for measuring …

Production Of Biobutanol From Biomass Using Novel Membrane Reactor: A P3 Experience, Ashley Haub

Chemical Engineering Undergraduate Honors Theses

Producing biobutanol from a waste product on a large scale is a novel idea. Because of this, there is very little research available in this area. Previous fermentation research has primarily focused on the production of ethanol or biobutanol using cellulosic or agricultural feed stocks. The Phase I research team, Team R azorbacks E ngineering FU el S olutions for E veryone (Team REFUSE), sought to design a fermentation process that would produce butanol from food waste. Team REFUSE cultivated a partnership with Chartwells, the campus food service provider for the University of Arkansas, for the acquisition of food waste. …

A Robust Process For Biodiesel Production Using Supercritical Methanol, Meagan Magie

Chemical Engineering Undergraduate Honors Theses

The overarching purpose of Phase I was to test, at the bench scale, a continuous supercritical methanol reactor, and to determine the feasibility of implementing the technology at full scale. Specific objectives in reaching this purpose included:
Objective 1: Choose a viable feedstock
Objective 2: Perform experiments for oil extraction
Objective 3: Design, build and operate a continuous supercritical methanol reactor
Objective 4: Design and simulate full scale biodiesel facility
Objective 4a: Perform life-cycle and economic analysis on full scale design
Objective 5: Prepare a Phase II P3 project to demonstrate the entire biodiesel process
Project Scope: The students performed …

Robust Image And Video Coding With Adaptive Rate Control, Hongqiang Wang

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

This dissertation is focused on the problem of rate allocation in a resource constrained environment and robustness of video coding over noise channels. A new rate allocation scheme that combines the traditional PCRD-Opt algorithm with the rho domain analysis is proposed for wavelet based image coders. The proposed scheme provides competitive performance as compared with the optimal PCRD-Opt algorithm, while with great reduction on complexity and computational costs. Rate allocation is developed for the Region-Of-Interest (ROI) in the wavelet transform domain for image coding. A recursive region growing method that deter mines the ROI in the transform domain is proposed. …

Local Head Loss Of Non-Coaxial Emitters Inserted In Polyethylene Pipe, Osvaldo Rettore Neto, Jarbas Honorio De Miranda, José Antonio Frizzone, Stephen R. Workman

Biosystems and Agricultural Engineering Faculty Publications

The design of a lateral line for drip irrigation requires accurate evaluation of head losses in not only the pipe but in the emitters as well. A procedure was developed to determine localized head losses within the emitters by the formulation of a mathematical model that accounts for the obstruction caused by the insertion point. These localized losses can be significant when compared with the total head losses within the system due to the large number of emitters typically installed along the lateral line. An experiment was carried out by altering flow characteristics to create Reynolds numbers (R) from 7,480 …

Distribution Tridimensionnelle De La Lumière Dans Une Strucutre De Tête D’Adulte Dérivée D’Un Acte Irm: Approche Par La Méthode De Monte Carlo, Chemseddine Mansouri, Jean-Pierre L'Huillier, Nasser H. Kashou

Biomedical, Industrial & Human Factors Engineering Faculty Publications

No abstract provided.

Cardiac Cell Mechanics At The Single Cell Level, John Mcrae

All Theses

The analysis of the cellular microenvironment is an area that has received much
attention recently in the study of the tractions cells use for locomotion. Specifically, the
study of cardiac cell mechanics is of particular interest as cardiac dysfunction is one of
the leading causes of death in America. This progression is fueled by the need to have a
system capable of reproducing mechanical environments before, during and after a
dysfunctional event in order to fully characterize the causes and prevent any permanent
damage. The current study proposes a system capable of providing quantitative
measurements of the cellular microenvironment while …

A Priori Analysis Of Subgrid Scalar Phenomena And Mass Diffusion Vectors In Turbulent Hydrogen-Oxygen Flames, Justin Foster

All Theses

Direct Numerical Simulations (DNS) of high pressure, turbulent H₂/O₂ non-premixed flames employing real gas effects, detailed chemistry, multicomponent, differential, and cross diffusion are conducted. The results of these simulations are analyzed to provide important subgrid information relevant to Large Eddy Simulation (LES) of turbulent combustion. Subgrid filtered scalar dissipation and scalar variances, species concentrations, reaction rates, and flame temperature are presented as a function of mixture fraction. The analysis also includes a detailed comparison of the actual filtered mass flux vectors with their corresponding forms evaluated with the filtered primitive variables. The results show a reasonable correlation …

Frequency-Domain Turbo Equalization For Mimo Underwater Acoustic Communications, Jian Zhang, Y. Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates a low-complexity frequency-domain turbo equalization (FDTE) based on linear minimum mean square error (LMMSE) criterion for single-carrier (SC) multiple-input multiple-output (MIMO) underwater acoustic communications (UAC). The receiver incorporates both the equalizer and the decoder which exchange the extrinsic information on the coded bits for each other to implement the iterative detection. The channel impulse responses (CIRs) required in the equalization are estimated in the frequency domain (FD) by inserting the well-designed pilot blocks which are frequency-orthogonal Chu sequences. The proposed SC-MIMO-FDTE architecture is applied to the fixed-to-fixed underwater data gathered during SPACE08 ocean experiments in October 2008, …

Multimodal Solution For A Waveguide Radiating Into Multilayered Structures -- Dielectric Properties And Thickness Evaluation, Mohammad Tayeb Ahmad Ghasr, Devin L. Simms, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Open-ended rectangular waveguides are widely used for microwave and millimeter-wave nondestructive testing (NDT) applications, such as detecting disbond and delamination in multilayered composite structures, thickness evaluation of dielectric sheets and coatings on metal substrates, etc. when inspecting a complex multilayered composite structure that is made of generally lossy dielectric layers with arbitrary thicknesses and backing, the dielectric properties of a particular layer may be of particular interest (e.g., radome inspection). The same is also true when one is interested in the thickness, or, more importantly, thickness variation, of a particular layer within such complex structures. An essential tool for closely …

Novel Near-Field Millimeter-Wave Differential Probe Using A Loaded Modulated Aperture, Mohamed A. Abou-Khousa, Sergey Kharkovsky, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field millimeter-wave techniques have effectively been used for nondestructive testing (NDT) and imaging applications for over a decade. The interaction of the fields and a structure under test (SUT) in the near field of a probe is more complex than that of the far-field interaction. In the near field, the distance between the probe and the SUT, which is referred to as the standoff distance, is an important measurement parameter, and when optimally chosen, it can significantly improve detection sensitivity. However, undesired changes in this parameter can adversely influence the detection outcome to the extent that a target may be …

2008 Ieee Swarm Intelligence Symposium (Sis 2008), Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

An Experiment On Integrated Thermal Management Using Metallic Foam, Derek M. Geiger

Master's Theses

This report details an approach to using metal foam heat exchangers inside an integrated thermal management system on a variable cycle engine. The propulsion system of interest is a variable cycle engine with an auxiliary, variable flow rate fan. The feasibility of utilizing an open-celled metallic foam heat exchanger in the ducting between the constant and variable-fans on this variable cycle engine to cool the avionics was explored using an experimental approach. Two heat exchangers, 6.3 inch width by 6.3 inch length by 0.5 inch thickness, were constructed from 20 and 40 pores per inch (PPI) metal foam and tested. …

Validation Of Linearized Flight Models Using Automated System-Identification, Keith Eric Rothman

Master's Theses

Optimization based flight control design tools depend on automatic linearization tools, such as Simulink®’s LINMOD, to extract linear models. In order to ensure the usefulness and correctness of the generated linear model, this linearization must be accurate. So a method of independently verifying the linearized model is needed. This thesis covers the automation of a system identification tool, CIFER®, for use as a verification tool integrated with CONDUIT®, an optimization based design tool. Several test cases are built up to demonstrate the accuracy of the verification tool with respect to analytical results and matches with LINMOD. Several common nonlinearities are …