Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2018

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 7021 - 7050 of 8951

Full-Text Articles in Engineering

Developing And Validating A New Product For Gripping And Pulling Cable, Tyler Miller Jan 2018

Developing And Validating A New Product For Gripping And Pulling Cable, Tyler Miller

Graduate Theses - Engineering Management

During on-site visits, it was discovered that the process of setting up cable for installation in conduit takes approximately 15 man-minutes of labor, costing contractors approximately $300 a day in labor costs. This integrated project examined the validity of a new product which would save labor costs by decreasing the preparation time for installing cable in conduit.

Marketing strategies were examined as well as business models. The design of the product consisted of 3D modeling, rapidly-manufactured prototypes, design space selection, testing, and refinement.

In time trials, the final product cut preparation time from 15 minutes to 1 minute, saving contractors …


Differences In The Throughput Performance Of The Warehouse Depending On The Quality Of The Calculation Parameters, David Sourek Jan 2018

Differences In The Throughput Performance Of The Warehouse Depending On The Quality Of The Calculation Parameters, David Sourek

15th IMHRC Proceedings (Savannah, Georgia. USA – 2018)

This article explores the quality level of the parameters that are used to determine the throughput performance of the warehouse. In our model case, this is a rack warehouse where the storage and picking of goods is ensured by forklifts. All kind of goods are stored on pallets. The aim of our research is to assess to what extent the quality level (accuracy) of the description of warehouse processes influences the accuracy of the determination of the throughput performance of the warehouse. In the first part of the article, we defined the parameters and the ways in which different levels …


Hydrogen Fuel Cells, Sydney Pilgrim, Skyler Smith Jan 2018

Hydrogen Fuel Cells, Sydney Pilgrim, Skyler Smith

ENgaging Educators in Renewable enerGY (ENERGY): Lesson Plans & Slideshows (2017-2019)

Hydrogen fuel cells are hydrogen powered energy sources. They convert chemical energy into electrical energy by separating water molecules into the two elements that make up water, Hydrogen (2) and Oxygen (1). Hydrogen fuel cells are looking to become a paramount energy producer to avoid consuming fossil fuels for power. Along with the abundance of Hydrogen in the atmosphere being a benefit of using Hydrogen powered fuel cells, the only emission from these energy sources is water vapor. Many car engines only operate at a 20% fuel efficiency, whereas fuel cell powered cars utilize 60% of the energy produced. Although …


Solar Tracking Sustainable Energy Education, Tara Hart, Donita Legonas Jan 2018

Solar Tracking Sustainable Energy Education, Tara Hart, Donita Legonas

ENgaging Educators in Renewable enerGY (ENERGY): Lesson Plans & Slideshows (2017-2019)

Two middle school science teachers collaborated with Georgia Southern lab students to conduct research and experimentation on the benefits of utilizing a dual-axis solar tracking system to assess the amount of voltage received during various times of the day. A smaller similar dual-axis solar tracking system was designed and fabricated to utilize in the teachers’ middle school classrooms in the study of renewable energy and the engineering and design process.


Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy Jan 2018

Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spacecraft descent-to-landing navigation often includes the use of a slant-range measurement, the distance from the spacecraft to a surface along the off-nadir pointing direction of the sensor. Modeling a slant range sensor requires a reference surface, approximations of which include spherical and ellipsoidal surfaces, spherical harmonic models, and topographical maps based on prior reconnaissance data. For the spherical and ellipsoidal reference surfaces, a closed-form solution of the slant-range measurement exists. However, these approaches are inaccurate with respect to the true surface. This paper develops a method to implement digital elevation maps of a given surface to create a topography-based model …


Electric Solid Propellant Ablation In A Pulsed Electric Thruster, Matthew S. Glascock, Joshua L. Rovey Jan 2018

Electric Solid Propellant Ablation In A Pulsed Electric Thruster, Matthew S. Glascock, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric solid propellants are advanced solid chemical rocket propellant that can be controlled (ignited, throttled and extinguished) with electric current. Work reported here focuses on application of electric solid propellant in a pulsed electric thruster similar to a pulsed plasma thruster. In the future it may be possible to develop a dual-mode electric solid propellant thruster that is switchable between steady applied electric current chemical mode and pulsed alternating electric current electric mode. Results presented here use a laboratory test thruster to create an arc discharge of 5-20 J per pulse in a cylindrical cavity of propellant. Results for Teflon …


Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars Jan 2018

Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Maintaining positive definiteness of a filter's error covariance estimate is of paramount importance to any stable and reliable estimation scheme. Two widely used methods for protecting a filter from loss of positive-definiteness are that of consider filtering and square-root filtering. Despite their widespread use in estimation applications, a filtering methodology that combines the two techniques has yet to be presented in a unified, streamlined architecture. This paper develops a new approach to square-root filtering using hyperbolic Householder reflections. A specialization of the method is considered to permit computationally efficient applications, and a numerical example pertaining to a ballistic reentry is …


Boundary-Layer Separation Control Using Laser-Induced Air Breakdown, Alfram Bright, Nathan Tichenor, Kevin Kremeyer, Richard Wlezien Jan 2018

Boundary-Layer Separation Control Using Laser-Induced Air Breakdown, Alfram Bright, Nathan Tichenor, Kevin Kremeyer, Richard Wlezien

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Modification of the flow separation characteristics of a laminar airfoil using a remotely located high-power laser was experimentally investigated in a low-speed, low-turbulence wind tunnel. A laminar airfoil model (chord length of 500 mm) was designed and fabricated to emulate the flight characteristics of a small aircraft. At 0 deg angle of attack, the airfoil model was determined to have an incipient laminar separation bubble on its lifting surface between 67 and 80% chord. A strong laser-induced breakdown was generated 2 mm upstream of the leading edge by focusing a collimated beam emitted from a 900 mW laser at 1064 …


Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei Jan 2018

Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microelectromechanical systems (MEMS) are core components in unmanned aerial vehicles (UAV). The precision of MEMS sensors is very important when the GPS signal is invalid. However, the precision and performance of MEMS sensors will be degraded by the changing of environment. Therefore, estimation and identification of the various noise terms existing in MEMS sensors are deemed to be necessary. The Allan variance is a common and standard method to analyze MEMS sensors, but it cannot be used to analyze the dynamic characteristics. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool …


Effects Of Subsurface Drainage Systems On Water And Nitrogen Footprints Simulated With Rzwqm2, Kristina J. Craft, Matthew J. Helmers, Robert W. Malone, Carl H. Pederson, Linda R. Schott Jan 2018

Effects Of Subsurface Drainage Systems On Water And Nitrogen Footprints Simulated With Rzwqm2, Kristina J. Craft, Matthew J. Helmers, Robert W. Malone, Carl H. Pederson, Linda R. Schott

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Developing drainage water management (DWM) systems in the Midwest to reduce nitrogen (N) transport to the northern Gulf of Mexico hypoxic zone requires understanding of the long-term performance of these systems. Few studies have evaluated long-term impacts of DWM, and the simulation of controlled drainage (CD) with the Root Zone Water Quality Model (RZWQM) is limited, while shallow drainage (SD) has not been examined. We tested RZWQM using nine years (2007-2015) of field data from southeast Iowa for CD, SD, conventional drainage (DD), and undrained (ND) systems and simulated the long-term (1971-2015) impacts. RZWQM accurately simulated N loss in subsurface …


A Tunable, Three-Dimensional In Vitro Culture Model Of Growth Plate Cartilage Using Alginate Hydrogel Scaffolds, Alek G. Erickson, Taylor D. Laughlin, Sarah M. Romereim, Catherine N. Sargus-Patino, Angela K. Pannier, Andrew T. Dudley Jan 2018

A Tunable, Three-Dimensional In Vitro Culture Model Of Growth Plate Cartilage Using Alginate Hydrogel Scaffolds, Alek G. Erickson, Taylor D. Laughlin, Sarah M. Romereim, Catherine N. Sargus-Patino, Angela K. Pannier, Andrew T. Dudley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Defining the final size and geometry of engineered tissues through precise control of the scalar and vector components of tissue growth is a necessary benchmark for regenerative medicine, but it has proved to be a significant challenge for tissue engineers. The growth plate cartilage that promotes elongation of the long bones is a good model system for studying morphogenetic mechanisms because cartilage is composed of a single cell type, the chondrocyte; chondrocytes are readily maintained in culture; and growth trajectory is predominately in a single vector. In this cartilage, growth is generated via a differentiation program that is spatially and …


Coupling Of Mechanical And Electromagnetic Fields Stimulation For Bone Tissue Engineering, Alyaa I. Aldebs Jan 2018

Coupling Of Mechanical And Electromagnetic Fields Stimulation For Bone Tissue Engineering, Alyaa I. Aldebs

Browse all Theses and Dissertations

Alternative bone regeneration strategies that do not rely on harvested tissue or exogenous growth factors and cells are badly needed. However, creating living tissue constructs that are structurally, functionally and mechanically comparable to the natural bone has been a challenge so far. A major hurdle has been recreating the bone tissue microenvironment using the appropriate combination of cells, scaffold and stimulation to direct differentiation. This project presents a bone regeneration formulation that involves the use of human adipose-derived mesenchymal stems cells (hASCs) and a 3D scaffold based on a self-assembled peptide hydrogel doped with superparamagnetic nanoparticles (NPs). Osteogenic differentiation of …


Mechanical Annealing Of Model Glasses: Effects Of Strain Amplitude And Temperature, Nikolai V. Priezjev Jan 2018

Mechanical Annealing Of Model Glasses: Effects Of Strain Amplitude And Temperature, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Molecular dynamics simulations are performed to examine the dynamic response of amorphous solids to oscillatory shear at finite temperatures. The data were collected from a poorly annealed binary glass, which was deformed periodically in the elastic regime during several hundred shear cycles. We found that the characteristic time required to reach a steady state with a minimum potential energy is longer at higher temperatures and larger strain amplitudes. With decreasing strain amplitude, the asymptotic value of the potential energy increases but it remains lower than in quiescent samples. The transient decay of the potential energy correlates well with a gradual …


Controlled Switching Of Reactive Loads And Commisioning Regimes, Eoin Cowhey Jan 2018

Controlled Switching Of Reactive Loads And Commisioning Regimes, Eoin Cowhey

Masters

Switching is a vital task in any power system for ensuring its safe and reliable operation. Switching may be necessary for fault clearance, to ensure wider system stability and to prevent damage to plant. It is essential for isolation, to allow technicians to carry out maintenance tasks safely. Also, switching of reactive loads such as shunt capacitor banks and shunt reactors, is crucial for controlling system voltage.

Switching of some loads however, may produce voltage transients and heavy transient inrush currents which can impact on wider system power quality, impact customers and cause damage or deterioration of the insulation of …


Design And Implementation Of A Micro-Inverter For Photovoltaic Applications, Chi-Thang Phan-Tan Jan 2018

Design And Implementation Of A Micro-Inverter For Photovoltaic Applications, Chi-Thang Phan-Tan

Masters

The objective of this work is to design and build a novel topology of a micro-inverter to directly convert DC power from a photovoltaic module to AC power. In the proposed micro-inverter, a structure with two power stages, which are DC/DC and then DC/AC converters, is used. A novel MPPT algorithm is implemented and evaluated in the DC/DC converter to optimize the solar panel energy production. The new method operates with an efficiency of 97.9%, which is a 1% improvement on the standard method, and a response time of

In this research, the following approach is taken. A literature review …


Rheology, Morphology And Electronic Properties Of Hybrid Copper Organic Decompose Conductive Ink, Chaiwat Klaewwigkij Jan 2018

Rheology, Morphology And Electronic Properties Of Hybrid Copper Organic Decompose Conductive Ink, Chaiwat Klaewwigkij

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hybrid Metal-Organic Decomposition (HMOD) inks containing alkanol amines copper complex solution with fine copper particles show high potential for flexible printed electronics application. Conductive patterns are fabricated from HMOD inks by screen printing onto a polyimide substrate. This work studies the effects of co-solvent, copper particles loading, and viscosity of the inks on properties of the conductive patterns obtained. Firstly, the effects of co-solvent related to the stability of the HMOD inks and the impact of preparation time related to the crack of the conductive pattern are examined. The HMOD inks are prepared from copper formate (CuF), and alkanol amines …


การปรับปรุงประสิทธิภาพการทำงานของโรงไฟฟ้าพลังงานแสงอาทิตย์โดยใช้การบำรุงรักษาเชิงรุก, มธุรส มิ่งมงคล Jan 2018

การปรับปรุงประสิทธิภาพการทำงานของโรงไฟฟ้าพลังงานแสงอาทิตย์โดยใช้การบำรุงรักษาเชิงรุก, มธุรส มิ่งมงคล

Chulalongkorn University Theses and Dissertations (Chula ETD)

แม้ว่ามีดำเนินงานการบำรุงรักษาเชิงป้องกันในโรงไฟฟ้าพลังงานแสงอาทิตย์แต่ยังคงมีการขัดข้องของเครื่องจักรต่างๆ โรงงานไฟฟ้าพลังงานแสงอาทิตย์ที่เป็นกรณีศึกษานี้ได้กำหนดค่าเป้าหมายความพร้อมของเครื่องจักรไว้สูงกว่า 99.25% เมื่อเวลาผ่านไปพบว่าค่าความพร้อมใช้งานมีแนวโน้มต่ำลง แม้ว่าก่อนการปรับปรุงมีค่าความพร้อมใช้งานเฉลี่ย 99.43% ส่วนเบี่ยงเบนมาตรฐานมีค่าสูงถึง 1.20% แสดงให้เห็นว่า การบำรุงรักษาเชิงป้องกันที่มีอยู่นั้นอาจไม่เพียงพอที่จะจัดการปัญหานี้ได้ งานวิจัยนี้จึงได้นำการบำรุงรักษาเชิงรุกมาเป็นกลยุทธ์ในการปรับปรุงค่าความพร้อมการใช้งานของเครื่องจักร มีการวิเคราะห์ผลกระทบของความเสียหาย โอกาสเกิดและความรุนแรง และมีการหาสาเหตุที่ทำให้เครื่องจักรเสีย หลังจากนั้นได้ทำการปรับปรุงแผนการบำรุงรักษาเชิงป้องกันและสร้างแผนการบำรุงรักษาเชิงพยากรณ์ หลังจากที่ดำเนินการตามแผนงานพบว่าสามารถทำให้ค่าความพร้อมใช้งานเพิ่มขึ้นเฉลี่ยเป็น 99.69% ส่วนเบี่ยงเบนมาตรฐานเป็น 0.41% เวลาเฉลี่ยในการขัดข้องของเครื่องจักรลดลง 63.90% จำนวนครั้งที่เกิดการขัดข้องลดลง 40.28% และกำลังการผลิตที่สูญเสียลดลงได้ 28.44%


การวิเคราะห์วอเตอร์ฟุตพรินต์ในกระบวนการผลิตเบนซีนและพาราไซลีน, เรืองรัตน์ เรืองเดช Jan 2018

การวิเคราะห์วอเตอร์ฟุตพรินต์ในกระบวนการผลิตเบนซีนและพาราไซลีน, เรืองรัตน์ เรืองเดช

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยฉบับนี้เป็นการวิเคราะห์ผลกระทบจากการใช้น้ำ ของกระบวนการผลิตเบนซีนและพาราไซลีน ทั้งการใช้น้ำทางตรงและทางอ้อม การใช้น้ำทางตรงประกอบไปด้วยการใช้น้ำในกระบวนการผลิตซึ่งสามารถวัดได้โดยตรงจากข้อมูลของโรงงาน และการใช้น้ำทางอ้อมประกอบไปด้วยการใช้น้ำในส่วนของการได้มาซึ่งวัตถุดิบ การใช้ไฟฟ้า การผลิตไอน้ำ การผลิตไนโตรเจน รวมถึงการใช้น้ำในกระบวนการขนส่ง ซึ่งโรงงานไม่สามารถวัดโดยตรงได้ต้องมีการเก็บข้อมูลจากแหล่งอ้างอิงอื่นๆที่เชื่อถือได้ วิธีการประเมินผลกระทบการใช้น้ำที่ใช้ในงานวิจัยฉบับนี้ใช้วิธีวอเตอร์ฟุตพรินต์ซึ่งเป็นวิธีที่ทำให้ทราบผลกระทบจากการใช้น้ำที่แท้จริงตลอดวัฏจักรชีวิตของผลิตภัณฑ์ โดยอ้างอิงวิธีการประเมินตามข้อกำหนดและแนวทางของ ISO 14046 ผลลัพธ์จากการประเมินพบว่าผลิตภัณฑ์เบนซีนและพาราไซลีน มีค่าวอเตอร์ฟุตพรินต์ซึ่งวัดผลกระทบในแง่ของการขาดแคลนน้ำ(Water Scarcity Footprint,WSF) ต่อ 1 กิโลกรัมเท่ากับ 0.613 LiterH2Oeq และ 1.432 LiterH2Oeq ตามลำดับ โดยทั้งเบนซีนและพาราไซลีนมีค่า WSF สูงสุดจากการใช้น้ำทางอ้อม ซึ่งมีค่าสูงในการใช้ไฟฟ้าและการได้มาซึ่งคอนเดนเสท และรองลงมาคือ WSF จากการใช้น้ำทางตรงซึ่งมีค่า WSF สูงในส่วนของการระเหยของน้ำในระบบหล่อเย็น แต่เนื่องการลดผลกระทบจากการใช้น้ำจะมีความเป็นไปได้ในการลดจากใช้น้ำทางตรงมากกว่าทางอ้อม เพราะสามารถควบคุมได้โดยตรงจากโรงงานถึงแม้ว่าอาจจะทำให้ผลกระทบลดลงได้ไม่มากก็ตาม จึงเสนอการนำมาตรการในการลดการใช้น้ำทางตรงร่วมด้วย โดยแบ่งมาตรการเป็น 2 ส่วนคือการลดผลกระทบที่เกิดจากการใช้น้ำทางตรง และการลดผลกระทบจากการใช้น้ำทางอ้อม เพื่อให้กระบวนการผลิตเบนซีนและพาราไซลีนเกิดการใช้น้ำอย่างมีประสิทธิภาพสูงสุด


Developing An Automated System For Supporting Strut Arrangement In Deep Excavation, Pisal Nov Jan 2018

Developing An Automated System For Supporting Strut Arrangement In Deep Excavation, Pisal Nov

Chulalongkorn University Theses and Dissertations (Chula ETD)

In strut arrangement, current software could detect the constructible problems like clashes. However, this software had some limitations including (1) unable to visualize all clash occurrences on each strut, (2) unable to distinguish between occurrence and non-occurrence of the clash, and (3) unable to check tolerance and spacing problems. Thus, the strut arrangement was still an inefficient process. The research objective was to develop an automated system for supporting strut arrangement in deep excavation. In the methodology, an in-depth interview was conducted to collect the information and knowledge of strut arrangement and analyzed with transcription analysis. This information and knowledge …


Assessing Corrosivity Of Galvanized Soil Reinforcements From Electrochemical Tests, Diana Alejandra Cabrera Jan 2018

Assessing Corrosivity Of Galvanized Soil Reinforcements From Electrochemical Tests, Diana Alejandra Cabrera

Open Access Theses & Dissertations

The accurate estimation of the service lives of mechanically stabilized earth (MSE) walls requires a proper evaluation of the corrosion potential through electrochemical test methods. Robust field tests are required to assess the corrosivity of galvanized metal used in MSE walls. To simulate an environment similar to an MSE wall, cylindrical soil specimens about 12 in. (300 mm) in diameter and 10 in. (250 mm) in height were constructed. For every specimen, two instruments were used. The first instrument measured the polarization resistance corrosion tests carried out on galvanized strips and meshes, as well as epoxy-coated rebars. The second instrument …


High Recovery Inland Desalination: A Technical And Economic Performance Evaluation Of Zero Discharge Desalination And Other Technologies, Malynda Aragon Cappelle Jan 2018

High Recovery Inland Desalination: A Technical And Economic Performance Evaluation Of Zero Discharge Desalination And Other Technologies, Malynda Aragon Cappelle

Open Access Theses & Dissertations

Increasing population and diminishing freshwater resources are leading to increased competition between users of freshwater, both in terms of surface water and groundwater. Desalination can augment the water supply, but conventional approaches like reverse osmosis are usually limited to 70-80% recovery. Inland brine disposal options are often limited, presenting significant technical and economic obstacles to implementing desalination technology. In comparison to conventional desalination technologies, high recovery desalination methods such as Zero Discharge Desalination (ZDD) offer substantially higher potable water yield (i.e., 95-98%) from brackish water. ZDD is a hybrid process that combines reverse osmosis (RO) or nanofiltration (NF) with electrodialysis …


Improving Time-Of-Flight And Other Depth Images: Super-Resolution And Denoising Using Variational Methods, Salvador Canales Andrade Jan 2018

Improving Time-Of-Flight And Other Depth Images: Super-Resolution And Denoising Using Variational Methods, Salvador Canales Andrade

Open Access Theses & Dissertations

Depth information is a new important source of perception for machines, which allow them to have a better representation of the surroundings. The depth information provides a more precise map of the location of every object and surfaces in a space of interest in comparison with conventional cameras. Time of flight (ToF) cameras provide one of the techniques to acquire depth maps, however they produce low spatial resolution and noisy maps. This research proposes a framework to enhance and up-scale depth maps by using two different regularization terms: Total Generalized Variation (TGV) and Total Generalized Variation with a Structure Tensor …


Design And Experimental Study Of A High Pressure And Supercritical Methane-Oxygen Burner, A S M Arifur Rahim Chowdhury Jan 2018

Design And Experimental Study Of A High Pressure And Supercritical Methane-Oxygen Burner, A S M Arifur Rahim Chowdhury

Open Access Theses & Dissertations

Directly heated supercritical oxy-fuel power cycles have potential to offer a higher thermal efficiency and lower pollutant emissions compared to existing power cycles. Recent thermodynamic analysis of the cycle performed by several groups including the UTEP-Air Liquide research team show that combustion in the vicinity of 300 bar pressure and 1000-1400 K temperature allows for relatively high system efficiencies while operating within the limit of practical combustor materials. However, the realization of directly heated supercritical power cycle requires combustion systems be designed to operate in supercritical conditions and at temperature far below the blowout limit of conventional flames (above 1500 …


Interference Analysis And Mitigation Of Telemetry (Tm) And 4g Long-Term Evolution (Lte) Systems In Adjacent Spectrum Bands, Juan Francisco Gonzalez Jan 2018

Interference Analysis And Mitigation Of Telemetry (Tm) And 4g Long-Term Evolution (Lte) Systems In Adjacent Spectrum Bands, Juan Francisco Gonzalez

Open Access Theses & Dissertations

Currently, the telecommunications, radio systems, and many other wireless services in the United States are using the spectrum from the 6 kHz to the 300 GHz frequencies. Although it may seem enough for said systems, as more users and devices are being introduced into the market, the spectrum is limiting the faster introduction of these devices and/or systems. The radio frequency spectrum is home to many transmissions, from amateur radio to cellphone applications, which all share similar frequency bands. By sharing, the number of applications can be increased in a single band, but their performance may be affected. Herein, experiments …


Additive Manufacturing Of Multi-Functional Nanocomposites For Sensor And Energy Storage Devices, Hoejin Kim Jan 2018

Additive Manufacturing Of Multi-Functional Nanocomposites For Sensor And Energy Storage Devices, Hoejin Kim

Open Access Theses & Dissertations

The goal of this research is to develop novel 3D printing process and design nanocomposites for piezoelectric and dielectric devices using fused deposition modeling (FDM) and stereolithography (SL) 3D printing techniques for use in sensor and energy storage applications. Techniques for electric and corona assisted in-situ poling during 3D printing were developed to improve the piezoelectric property and ease of manufacture. Poly(vinylidene fluoride) (PVDF) and barium titanate (BaTiO3, BT) are well-known for their high piezo- and dielectric constants among polymers and ceramics, while multi-walled carbon nanotubes (CNTs) were introduced to improve efficiency of stress reinforcement and conductivity for charge carriers …


Design And Simulation Of Mems Actuators To Study Strain Behavior Of 2d Materials, Mariana Martinez Jan 2018

Design And Simulation Of Mems Actuators To Study Strain Behavior Of 2d Materials, Mariana Martinez

Open Access Theses & Dissertations

Since the 60s the semiconductor industry has successfully been able to keep pace with Moore's Law due to the effective scaling of the silicon-based transistor. However, as scaling technology improves, passive power density has begun to dominate the overall power consumption of transistors. The inability to scale power density alongside the decreasing transistor dimensions has hindered the efficiency trend observed in the last decades. Thus, new alternatives have been researched to overcome the current power crisis. Micro-electro-mechanical system (MEMS) actuators offer excellent on/off ratios with very steep transitions. Furthermore, two-dimensional transition-metal dichalcogenide (TMD) materials have been studied due to their …


Characterization Of 3d Printed Polylactic Acid/ Polycaprolactone/Titanium Dioxide Composites For Bone Replacement And Grafting, Sandra Elena Najera Beltran Jan 2018

Characterization Of 3d Printed Polylactic Acid/ Polycaprolactone/Titanium Dioxide Composites For Bone Replacement And Grafting, Sandra Elena Najera Beltran

Open Access Theses & Dissertations

A material that mimics the properties of bones was developed by optimizing the ratio of polymer composites of polylactic acid (PLA) and poly-ε-caprolactone (PCL), containing small amounts of titanium oxide (TiO2). Although titanium-based alloys have commonly been used for bone replacement procedures due to their biocompatibility with the human body and their mechanical properties, stress shielding continues to be a problem. The structure of a bone has a porosity which permits the flow of nutrients, blood, oxygen and minerals, and is an issue at the time of creating bone replacements using conventional methods. PLA and PCL have been used in …


The Design Of A Rocket Propulsion Labview Data Acquisition And Control System, Dylan Allan Ott Jan 2018

The Design Of A Rocket Propulsion Labview Data Acquisition And Control System, Dylan Allan Ott

Open Access Theses & Dissertations

When designing a rocket engine, both the propulsion system and propellant choice(s) are an important deciding factor. Desired rocket engine behavior, specific impulse, and levels of thrust are all different between the various propulsion systems. A bi-propellant cryogenic liquid 5lbf, 500lbf, and 2000lbf rocket engine was designed and manufactured by UTEP. The 5lbf rocket engine is a Reaction Control Engine and the 500lbf and 2000lbf rocket engine is a throttleable Main Engine. To provide a reliable and safe data acquisition and control system for this experiment, a Real-Time control platform was needed. A compact DAQ system was purchased and configured …


Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala Jan 2018

Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala

Open Access Theses & Dissertations

Engineered nanomaterials (ENMs) have proven to be one of the emerging chemicals of concern in the contemporary times. Soil acts as one of the major sinks of these ENMs. Reports have shown that ENMs have varied effects on soil biota. Particularly, their effects on plants are inconsistent. Amongst these ENMs, ZnO nanoparticles (nZnO) are the fourth largest raw materials in the nanotechnology industry. Globally, it is estimated that around 34,000 tons of n ZnO are utilized per year. The nZnO exposure on terrestrial plants yielded both beneficial as well as detrimental effects. Recently, there is an emerging evidence about the …


Solvent And Concentration Effects Governing The Hierarchical Organization Of Asphaltenes: A Small-Angle X-Ray Scattering Study, Hasan Rejoanur Rahman Jan 2018

Solvent And Concentration Effects Governing The Hierarchical Organization Of Asphaltenes: A Small-Angle X-Ray Scattering Study, Hasan Rejoanur Rahman

Open Access Theses & Dissertations

Asphaltenes are a group of planar molecules found in crude oil and are prone to aggregation which often causes blockage of pipes along the oil production stream resulting a huge economic downside. In an effort to understand the hierarchical organization of asphaltene in different solvents and concentrations, the solution structure of various asphaltene solutions were studied using small-angle x-ray scattering (SAXS). Solvents were chosen based on miscibility maps. Such maps are generated on the critical value of the solubility parameter difference between asphaltenes or asphaltene components, and a range of solvents. The critical factors that affect asphaltene and asphaltene component …