Engineering Commons^™

Formulation Of Nanoparticle Systems For Drug Delivery Application In Biomedical Sciences, Victor Alfredo Rodriguez

Open Access Theses & Dissertations

Antibiotic-resistant strains of bacteria may result in serious infections which are difficult to treat. In addition, the poor antibiotic pipeline has also contributed to the crisis. Recently, the complex of furosemide and silver (Ag-FSE) has been reported as a potential antibacterial agent. However, its poor aqueous solubility is limiting its activity as an effective antibacterial agent. The purpose of this study was to encapsulate Ag-FSE into chitosan nanoparticles (CSNPs) and evaluate antibacterial efficacy. Ag-FSE CSNPs were prepared using ionic gelation technique. The particle size, polydispersity index and zeta potential of Ag-FSE CSNPs were determined using dynamic light scattering (DLS) technique. …

Extraction Of Fiber Morphology From Sem Images For Quality Control Of Fiber Reinforced Composites Manufacturing, Md Fashiar Rahman

Open Access Theses & Dissertations

The morphology of fibers (e.g. spatial uniformity, orientation, and length) plays a decisive role in determining the material properties or fabrication quality of fiber-reinforced nanocomposites. Hence, determining the morphology becomes a very critical issue in the field of nanocomposite quality control. The conventional way of quality inspection is to take the scanning electron microscopic (SEM) images of the cross-section of composite material and do the visual checking of these SEM images to evaluate the nanofiber alignment and length distribution. But this type of inspection is often subjective, inaccurate and time consuming. Moreover, the extremely small size of nanofibers makes the …

Evaluation Of Commercial Pervaporation Membranes For Desalination Of Saline And Brackish Waters, Andres F. Sanchez

Open Access Theses & Dissertations

Pervaporation is a solution separation method that occurs by vapor transport through a selective membrane. As the need to provide drinking water to the growing population increases, pervaporation has potential merit as an alternative desalination technology, especially for water with very high salinity.

To our knowledge, there are no commercially available pervaporation membranes made specifically for desalination applications. Thus, the membranes PERVAP 4100 and PERVAP 4101 manufactured by DeltaMemAG were tested to evaluate their performance in desalination. Because the driving force in pervaporation is the difference in vapor pressure between the feed side and the permeate side of the membrane, …

Evaluation Of Large Area Additively Manufactured Fiber Reinforced Acrylonitrile Butadiene Styrene (Abs), Kevin Schnittker

Open Access Theses & Dissertations

To enable the advancement of large-scale additive manufacturing processes, it is necessary to establish and standardize methodologies to characterize the mechanical properties of printed test coupons. Due to the large size of the print beads, conventional test standards are inadequate. The focus of this study was to determine the feasibility of using Digital image correlation (DIC) technology as a key enabler for robust data collection of strain measurements of large 3D printed parts. To incorporate the DIC measurements, a novel method was developed to prepare large 20 wt.% glass filled ABS test coupons for adequate contrast. Through this technique, Poisson's …

Assessing Performance Of Detectors Of High Frequency Oscillations In Eeg Signals, Deeksha Seetharama Bhat

Open Access Theses & Dissertations

Attempts to perform epileptic seizure prediction have been made for decades, but there is no solution yet that is generally effective, though some progress in this area has been reported. Interictal epileptic spikes were considered as the only biomarkers of seizure-generating brain tissue until the recent discovery of high-frequency oscillations (HFOs) in electroencephalographic (EEG) signals, with frequency contents in the range from 80 Hz to 800 Hz. HFOs are now considered as biomarkers of epileptogenic tissue and the seizure onset zone. However, there are challenges in the definition and detection of HFO events which complicate this perspective. In studies about …

Probabilistic Graphical Models Follow Directly From Maximum Entropy, Anh H. Ly, Francisco Zapata, Olac Fuentes, Vladik Kreinovich

Departmental Technical Reports (CS)

Probabilistic graphical models are a very efficient machine learning technique. However, their only known justification is based on heuristic ideas, ideas that do not explain why exactly these models are empirically successful. It is therefore desirable to come up with a theoretical explanation for these models' empirical efficiency. At present, the only such explanation is that these models naturally emerge if we maximize the relative entropy; however, why the relative entropy should be maximized is not clear. In this paper, we show that these models can also be obtained from a more natural -- and well-justified -- idea of maximizing …

Simplest Polynomial For Which Naive (Straightforward) Interval Computations Cannot Be Exact, Olga Kosheleva, Vladik Kreinovich, Songsak Sriboonchitta

Departmental Technical Reports (CS)

One of the main problem of interval computations is computing the range of a given function over given intervals. It is known that naive interval computations always provide an enclosure for the desired range. Sometimes -- e.g., for single use expressions -- naive interval computations compute the exact range. Sometimes, we do not get the exact range when we apply naive interval computations to the original expression, but we get the exact range if we apply naive interval computations to an equivalent reformulation of the original expression. For some other functions -- including some polynomials -- we do not get …

How To Gauge The Accuracy Of Fuzzy Control Recommendations: A Simple Idea, Patricia Melin, Oscar Castillo, Andrzej Pownuk, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

Fuzzy control is based on approximate expert information, so its recommendations are also approximate. However, the traditional fuzzy control algorithms do not tell us how accurate are these recommendations. In contrast, for the probabilistic uncertainty, there is a natural measure of accuracy: namely, the standard deviation. In this paper, we show how to extend this idea from the probabilistic to fuzzy uncertainty and thus, to come up with a reasonable way to gauge the accuracy of fuzzy control recommendations.

Normalization-Invariant Fuzzy Logic Operations Explain Empirical Success Of Student Distributions In Describing Measurement Uncertainty, Hamza Alkhatib, Boris Kargoll, Ingo Neumann, Vladik Kreinovich

Departmental Technical Reports (CS)

In engineering practice, usually measurement errors are described by normal distributions. However, in some cases, the distribution is heavy-tailed and thus, not normal. In such situations, empirical evidence shows that the Student distributions are most adequate. The corresponding recommendation -- based on empirical evidence -- is included in the International Organization for Standardization guide. In this paper, we explain this empirical fact by showing that a natural fuzzy-logic-based formalization of commonsense requirements leads exactly to the Student's distributions.

Classification Of Radar Jammer Fm Signals Using A Neural Network Approach, Ariadna Estefania Mendoza

Open Access Theses & Dissertations

A Neural Network (NN) used to classify radar signals is proposed for the purpose of military survivability and lethality analysis. The goal of the NN is to correctly differentiate Frequency-Modulated (FM) signals from Additive White Gaussian Noise (AWGN) using limited signal pre-processing. The FM signals used to test the NN approach are the linear or chirp FM and the power-law FM. Preliminary simulations using the moments of the signals in the time and frequency domain yielded better results in the frequency domain, suggesting that time domain training would not be as effective frequency domain training. To test this hypoThesis, we …

On-Orbit Autonomous Repair: Systems Design And Project Management Of The Orbital Factory Ii Cube-Satellite, Mike Louis Everett

Open Access Theses & Dissertations

In 2016, a group of faculty, staff and students from the University of Texas at El Paso submitted a formal entry to the ULA CubeCorp competition to launch a 1U Cube Satellite into Orbit. In September of 2016, the team was awarded a launch opportunity to a prestigious GTO orbit to test and validate electrically conductive printing on within the Van Allen Radiation belts. This Dissertation is focused upon the management plan and specific decision that were implemented to accomplish this goal within a one year time frame and on a conservative budget.

In 2018 this satellite will launch aboard …

Investigation On A Cooling Channel Design For A High Heat Flux Oxy-Fuel Direct Power Extraction Combustor, Luisa Alejandra Cabrera Maynez

Open Access Theses & Dissertations

The implementation of oxy-fuel technology in fossil-fuel power generation could result in a drastic increase of system efficiencies and a reduction of emissions. While typical system temperatures are dictated by material constraints, open-cycle magnetohydrodynamic (MHD) power generators have the potential to utilize the energy of undiluted flames. This work presents design and modeling strategies to develop steady-state supersonic MHD combustors operating at temperatures exceeding 3000 K. Throughout the study, computational fluid dynamics (CFD) models were extensively used as a design and optimization tool. A proof-of-concept 60 kWth model was designed, manufactured and tested in accordance to methods relevant to rocket …

The Development Of A Data Acquisition And Control System For Rocket Propulsion Research, Javier Chaparro

Open Access Theses & Dissertations

The MIRO Center for Space Exploration Technology Research (cSETR) at the University of Texas at El Paso (UTEP) has developed the Technology Research and Innovation Acceleration Park (tRIAC) in Fabens, Texas. This facility has been established in order to meet new research demands for experimental testing of Liquid Oxygen (LOX)/Liquid methane (LCH4) propulsion systems. Within this facility, a vertical test stand capable of measuring up to 3,000lbf will be constructed for main engine testing of the JANUS and DAEDALUS vehicle programs.

In order to meet challenges of precise remote system operation and data acquisition during engine testing, cSETR designed and …

Next Generation Exa-Scale Capable Software For High Fidelity Physics Aware Simulations, Ashesh Kumar Chattopadhyay

Open Access Theses & Dissertations

Physics aware simulations, often arising in problems of fluid dynamics, aerodynamics and multi-physics areas have demanded the need for computing software that has the capability to resolve the complexities at multiple scales to analyze and visualize the effects of their interactions with the surroundings. Usually the governing dynamics of these phenomenon appear in the form of complex partial differential equations whose numerical solutions impose various constraints on computational complexity, programming time and efficient throughput. In this scenario, the need of computing software that can solve very large problems resolving the physics of these phenomenon at multiple scales is imperative. Despite …

Characterization And Comparison Of Metallic And Ceramic Parts Fabricated Using Powder Bed-Based Additive Manufacturing Technologies, Jose Angel Gonzalez

Open Access Theses & Dissertations

Additive manufacturing (AM), or layer-by-layer part fabrication, is enabling the materialization of ideas that were near to impossible to achieve in the past, while providing advantages that include reduced material footprint, increased complexity, reduced lead times, etc. AM has been integrated to highly specialized markets that include aerospace, military, automotive, biomedical, and prototyping.

Although an apparent growth is being witnessed across nearly all AM platforms, technologies with capabilities of producing metallic parts have arguably received the most widespread interest, with powder bed fusion (i.e. electron beam melting and selective laser melting). This class of AM technology produces parts by judiciously …

Quantifying The Characteristic Length Of A Combustor For An Ionic Liquid Monopropellant Thruster, Kimberly Marie Hogge

Open Access Theses & Dissertations

Ionic liquid monopropellants are currently being researched as a promising alternative to hydrazine in propulsion systems. This report presents a flame study that delineates the flame length of the expected decomposition products from an ionic liquid monopropellant. Through these studies, the characteristic length of a combustion chamber will be defined through calculations and empirical correlations. There is limited information on designing a propulsion system for an ionic liquid monopropellant. Therefore, defining the magnitude for an effective characteristic length serves as beneficial in designing a propulsion system for an ionic liquid monopropellant thruster.

Process Development And Characterization Of Smart Parts Fabricated Using Powder Bed Fusion Additive Manufacturing Technologies, Mohammad Shojib Hossain

Open Access Theses & Dissertations

The fields of modern energy conversion, e.g., fossil fuel, natural gas, and coal power plants, are in increased need of health monitoring and data collection (temperature, pressure, and flow rate) to improve process efficiency and satisfy the demand for clean energy. In situ process monitoring can lead to a robust automated system to achieve the goal. The monitoring equipment or sensors in energy systems components (e.g., pressure tube, turbine blade, and fuel injector) undergo high temperature, high pressure, and corrosive environments; for example, combustion inlet conditions can reach up to 810 K and 2760 kPa [1]. Therefore, a reliable, accurate, …

Design And Development Of A Delivery System For Green Ionic Monopropellants And Testing Of A 22n Thruster, Jaclyn Mona Mejia

Open Access Theses & Dissertations

LMP-103S and AFM-315E are emerging propellants that are less toxic to the environment than the propellants currently being used in spacecraft propulsion. Both propellants are a blend of liquid fuel, oxidizer and a majority percent of water. The diluted solutions enable the capability to handle and store the propellants with fewer requirements; for this reason, it decreases the overall cost of the propellants since it needs less precautions. The Missile Defense Agency (MDA) awarded the University of Texas at El Paso (UTEP) a contract to further research green propellants and eventually replace Hydrazide.

Comparison Of Extruder Systems For 3d Printer Filament Fabrication, Adriana Ramirez

Open Access Theses & Dissertations

Additive Manufacturing (AM) has grown in popularity over the past thirty years, due to its versatility, short design to product cycle, and capability to fabricate complex geometries, which cannot otherwise be produced. There exist several platforms that are able to print objects composed of different materials, making this technology significant in different fields such as: automotive, aerospace, medical, electronics, amongst others. Though several types of AM technologies are available, the expiration of the patents on fused deposition modeling (FDM) in 2009 has led to a widespread use of this platform in academia and home use settings.

Widespread use of FDM-type …

Healthcare Utilization Awareness And Labor Monitoring Methodology: A Theoretical I.M.S.E. Approach To Risk Minimization And Human Metrics Capturing In The Nursing Workforce, Luis Reyes

Open Access Theses & Dissertations

The healthcare industry is so complex and dynamic that the development of any tool designed to promote positive patient outcomes nearly requires the developer to be an actual healthcare practitioner. Many healthcare tools exists that initially give the perception that there will be no future requirements that may hinder the tools' integrity, but more often than not, the unexpected occurs. The future is one unpredictable element of life that most engineers wish they could capture with optimal precision. I.M.S.E. (Industrial, Manufacturing and Systems Engineering) applications do not assist with fortune telling, but they do assist with creating robust tools designed …

Impact Of Reclaimed Asphalt Pavement And Recycled Asphalt Shingles On Laboratory And Field Performance Of Texas Asphalt Concrete Pavements, Berenice Salaices Gomez

Open Access Theses & Dissertations

The use of recycled materials in Asphalt Concrete (AC) mixes is highly promoted in the transportation industry. Recycled materials minimize the use of virgin materials, reduce the consumption of resources, and cut costs for new construction or rehabilitation projects. The incorporation of Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) in the AC mixture is promoted as long as equal or improved performance is achieved. The Texas Department of Transportation (TxDOT) is currently placing asphaltic concrete (AC) mixes that are lasting less than their expected performance life when recycled materials are used.

The objective of this Thesis is to …

Modeling The Effects Of Manufacturing Geometric Imperfections In The Buckling Analysis Of Three-Dimensional Structures, Juan Carlos Salcido

Open Access Theses & Dissertations

Reticulated three-dimensional structures follow design practices based on the common assumption that joints are either rigid, or pinned. However, the actual non-linear behavior of the jointing system interaction is required to be incorporated into the analysis of the structure to accurately predict its buckling stability. Besides, currently, there is a concern on how manufacturing imperfections of these jointing systems affect the global behavior of three-dimensional structures. This Dissertation incorporates and captures the effect that manufacturing geometric imperfections in the fir-tree jointing system produce in the non-linear buckling behavior of three-dimensional structures.

To understand the effect that initial manufacturing imperfections of …

Experimental Investigation Of Cryogenic Convection And Boiling In Traditionally And Additively Manufactured Rocket Engine Cooling Channels, Armando Sandoval

Open Access Theses & Dissertations

The Center for Space Exploration and Technology Research at the University of Texas at El Paso, has designed, built, and optimized an experimental high heat flux test facility to investigate the heat transfer coefficient of liquid methane and other cryogenic propellants for regenerative cooled rocket engine design. The system is composed of a copper conduction based thermal concentrator that delivers heat flow into a single sub-scaled cooling channel (test article). This study focuses on optimizing this design of the high heat flux test facility to develop a more accurate method for measuring the conductive heat flow going into the cooling …

Design & Analysis Of A 500 Lbf Liquid Oxygen And Liquid Methane Rocket Engine, Daniel Eduardo Vargas

Open Access Theses & Dissertations

The rapid growth in demand for spacecraft technologies has spawned a need for a variety of new and innovative research. The utilization of liquid oxygen (LOX) and liquid methane (LCH4) in rocket engines have played an important role in space exploration efforts to promote missions to Mars with in-situ resource utilization for propellant production. This will allow the production of fuel needed to come back to Earth making the overall mission more cost effective by enabling larger usable mass.

The Center for Space Exploration and Technology Research has focused its efforts to developing Liquid Oxygen (LOX) and Liquid Methane (LCH4) …

Material Behavior Of Window 7 Carrier Panel Tiles And Thermal Pane Fragments Recovered From The Space Shuttle Columbia, Brenda Roseanne Arellano

Open Access Theses & Dissertations

Since the end of the space shuttle program, a new generation spacecraft has been developed to transport humans back into space. NASAâ??s Orion will carry a crew beyond low-earth orbit and the exploration of Mars may be possible in the future. Space safety becomes significant with human spaceflight and the risks are high. However, aerospace materials may provide opportunities to prevent future disasters. When the space shuttle Columbia disintegrated during re-entry in 2001, thousands of debris were collected for analysis. In contrast, when the Challenger space shuttle broke apart in 1986, all shuttle debris were buried. These tragic disasters are …

Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc

Open Access Theses & Dissertations

Methods built on Raman spectroscopy have shown major potential in describing and discriminating between malignant and benign specimens. Accurate, real-time medical diagnosis benefits in substantial improvements through this vibrational optical method. Not only is acquisition of data possible in milliseconds and analysis in minutes, Raman allows concurrent detection and monitoring of all biological components. Besides validating a significant Raman signature distinction between non-tumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, this study reveals a label-free method to assess overexpression of epidermal growth factor receptors (EGFR) in tumor cells. EGFR overexpression sires Raman features associated with phosphorylated threonine and serine, and …

The Interplay Between Grain Size And Austenite Stability On Deformation Behavior Of High Strength-High Ductility Combination Nanostructured Stainless Steel, Venkata Sai Ananth Challa

Open Access Theses & Dissertations

The concept of phase reversion involving severe cold deformation of metastable austenite to generate strain-induced martensite, followed by temperature-time annealing sequence, was used to obtain varying grain size from nanograined/ultrafine-grained (NG/UFG) to coarse-grained (CG) regime. This concept was used to obtain â??high strength-high ductilityâ?? combination in nano/ultrafine-grained (NG/UFG) austenitic stainless steel. Using this concept, the objective of the study is to elucidate the dependence of grain size on deformation mechanisms and deformation-induced microstructural changes. The objective was accomplished by combining depth-sensing nanoindentation experiments conducted at various strain rates, and interrupted tensile testing at various strain and post-mortem analyses of deformed …

Dft Study Of Adsorption Of Trimetallic Endohedral Fullerenes On Graphene, Nakul Nitin Karle

Open Access Theses & Dissertations

A density functional theory (DFT) study on the geometric and electronic structure of C60 and Sc3N@C80 along with their adsorption on pristine single layer graphene (SLG) is presented. C60 is found to adsorb in two nearly degenerate configurations: (i) with a pentagon facing the SLG, which is the most stable one, and (ii) with a hexagon facing the SLG in a face-to-face perfect alignment, rarely common in Ï?â??Ï? interactions, 0.06 eV higher in energy. The calculated binding energy of 0.76 eV, which includes dispersion effects, is in good agreement with previous theoretical and experimental reports. On the contrary, Sc3N@C80 adsorption …

Design And Development Of A Foil Application Tool For A Foil Embedding Process In The Multi3d Manufacturing System, Betty Elizabeth Mckenzie

Open Access Theses & Dissertations

Additive manufacturing (AM) encompasses different technologies, including material extrusion 3D printing, a technology commonly referred to as fused deposition modeling (FDM), which is the focus of the work described in this manuscript. Additive manufacturing is a growing technology with many applications in numerous fields from the air force to medical offices. FDM is a process that uses thermoplastics, in this case polycarbonate (PC), where the PC is heated and selectively dispensed in a layer-by-layer process to create a 3D printed part. Currently, FDM systems have advantages over subtractive manufacturing or machining because cavities and other components (e.g., microchips, valves, and …

Production And Functionality Of Melanocytes For Use In 3d-Printed Pigment-Capable Skin Tissue, Corinne Nicole Wittmann

Open Access Theses & Dissertations

Skin grafts are used in a variety of medical procedures including burn treatment, skin cancer removal, chronic wound/ulcer treatment, skin infections and diseases, large wound closure and in elective plastic surgeries. Ideally, skin grafts are harvested directly from the patient. However, in some cases, direct harvesting of skin grafts is not possible. In these situations, an equivalent skin substitute obtained through another source is utilized. There will always be a greater risk of rejection in such cases and therefore is only intended to be a temporary treatment. A possible solution to lessen the risks and issues associated with skin grafts …