Mechanical Engineering Commons^™

Spike Nozzle Design For Use In Nanosat Orbital Maneuvering, Drew Nemeth

Undergraduate Research Symposium Podium Presentations

Annular spike nozzle engines have long been the holy grail of rocket engine design, promising superior performance in a smaller footprint when compared to conventional bell nozzles. However, flaws inherent to the design of spike nozzles have prevented widespread adoption and testing. As a result, research on potential applications has been quite sparse. This project aims to further spike nozzle research by investigating rarely tested materials that literature suggests have potential for use in a spike nozzle design. The goal of the overall research project is to examine 3D printed polycarbonate component longevity under conditions representative of a small satellite …

Toward The Use Of Drones For Photovoltaic Panel Inspection, Fausto Vega

Undergraduate Research Symposium Posters

The monitoring of photovoltaic panels is an essential task to maintain the efficiency of the power plant. The conventional form of inspection consists of manual inspection with a thermal camera which takes several days as fields contain thousands of panels. Solar panel installation is costly, and the installation does not guarantee maximum power generation without proper maintenance and handling. A drone with a thermal camera payload was developed to reduce labor costs as well as increase efficiency of the inspection as it can survey the field with a large field of view. Several image processing methods were used to process …

Foot Contact Dynamics And Fall Risk Among Children Diagnosed With Idiopathic Toe Walking, Rahul Soangra, Michael Shiraishi, Richard Beuttler, Michelle Gwerder, Lou Anne Boyd, Venkatesan Muthukumar, Mohamed Trabia, Afshin Aminian, Marybeth Grant-Beuttler

Electrical & Computer Engineering Faculty Research

Children that are diagnosed with Idiopathic Toe walking (cITW) are characterized by persistent toe-to-toe contacts. The objective of this study was to explore whether typical foot contact dynamics during walking predisposes cITW to a higher risk of falling. Twenty cITW and age-matched controls performed typical and toe walking trials. The gait parameters related to foot contact dynamics, vertical force impulses during stance, slip, and trip risk were compared for both groups. We found that cITW manifest less stable gait and produced significantly higher force impulses during push-off. Additionally, we found that cITW had a higher slip-initiation risk that was associated …

Morphology Control Of One-Dimensional Gallium Nitride Nanostructures By Modulating The Crystallinity Of Sacrificial Gallium Oxide Templates, Yun Taek Ko, Mijeong Park, Jingyeong Park, Jaeyun Moon, Yong Ho Choa, Young In Lee

Mechanical Engineering Faculty Research

In this study, we demonstrated a method of controllably synthesizing one-dimensional nanostructures having a dense or a hollow structure using fibrous sacrificial templates with tunable crystallinity. The fibrous ga2o3 templates were prepared by calcining the polymer/gallium precursor nanofiber synthesized by an electrospinning process, and their crystallinity was varied by controlling the calcination temperature from 500oC to 900oC. gaN nanostructures were transformed by nitriding the ga2o3 nanofibers using NH3 gas. All of the transformed gaN nanostructures maintained a one-dimensional structure well and exhibited a diameter of about 50 nm, but their morphology was clearly distinguished according to the crystallinity of the …

Direct Energy Deposition Of Mo Powder Prepared By Electrode Induction Melting Gas Atomization, Goo Won Roh, Eun Soo Park, Jaeyun Moon, Hojun Lee, Jongmin Byun

Mechanical Engineering Faculty Research

Molybdenum (Mo) is used to form a barrier layer for metal wiring in displays or semiconductor devices. Recently, researches have been continuously attempted to fabricate Mo sputtering targets through additive manufacturing. in this study, spherical Mo powders with an average particle size of about 37 um were manufactured by electrode induction melting gas atomization. Subsequently, Mo layer with a thickness of 0.25 mm was formed by direct energy deposition in which the scan speed was set as a variable. According to the change of the scan speed, pores or cracks were found in the Mo deposition layer. Mo layer deposited …

Effect Of Heat Treatment On Microstructure And Hardness Of A Worn Rail Repaired Using Laser Powder Deposition, Ershad Mortazavian, Zhiyong Wang, Hualiang Teng

Mechanical Engineering Faculty Research

The frequent replacement of worn rails on tracks brings an immense economic burden on the railroad industry, and also causes significant interruptions to railroad operation. Restoration of worn rails via laser powder deposition (LPD) can considerably reduce the associated maintenance costs. This study was focused on the use of LPD to repair the worn profile of a standard U.S. rail. The microstructure of the 304L stainless steel deposits with a minimum hardness of 85 HRB was composed of austenite, δ-ferrite, and sigma. Micropores were dispersed throughout the deposit, and microcracks were found at the rail-deposition interface. The pearlitic rail substrate …

Minimizing Visual Defects Through Augmentation Of Computer Aided Diamond Rough Planning, Abhijith Prabhu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many computer aided design systems today utilize a workflow where physically accurate rendering of the product is not a functional component of its design process. This gap in workflow can lead to a sub optimal product or even a longer iterative design process in instances where a product's visual attributes and aesthetics are one their primary functional characteristic.

Diamonds are graded on their carat, color, clarity and cut, referred to as the 4Cs of a diamond; a standard set by G.I.A. and universally agreed upon. The cut of a diamond significantly affects the rest of the characteristics as it modifies …

Validation Of Novel Obstructive Sleep Apnea Treatment With Silicone Gel Experimental Models, Dustin Walter Burd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Predictive modeling to increase treatment success rates for surgical procedures is becoming more common in the scientific community. For obstructive sleep apnea (OSA), modeling has been predominately performed using computers as opposed to experimental models. Computer simulation saves time by eliminating the need to fabricate complex experimental models but comes at the expense of insight gained through physical observations made in real time. Experimental models for studying OSA are needed to validate computational work, provide perspective on anatomical scale and demonstrate complex deformations in real time. This work addresses prior hurdles in experimental model fabrication with a novel process using …

Material Model Characterization Of A Ti/Sic Metal Matrix Nanocomposite Coating Subjected To Hypervelocity Impact, Pouya Shojaei, Riccardo Scazzosi, Mohamed Trabia, Brendan Otoole, Marco Giglio, Xing Zhang, Yiliang Liao, Andrea Manes

Mechanical Engineering Faculty Research

Titanium alloys have been extensively used in the aerospace industry because of their outstanding properties, such as high strength-to-weight ratios, high corrosion resistances, and high melting points. However, it is hypothesized that the performance of titanium alloys can be further enhanced to be more resistant to hypervelocity impact by coating them. Earlier experimental investigations showed that coating a Ti-6Al-4V substrate by Ti/SiC Metal Matrix Nanocomposite (MMNC) improved hypervelocity impact resistance of the composite. The coating had 7% SiC by volume. These experiments were simulated using the Smoothed Particle Hydrodynamics (SPH) modeling approach. Johnson-Cook material models were used for the Ti-6Al-4V …

Unmanned Aerial System Integrated Sensor For Remote Gamma And Neutron Monitoring, Alexander Barzilov, Monia Kazemeini

Mechanical Engineering Faculty Research

Tools for remote radiation sensing are essential for environmental safety and nuclear power applications. The use of unmanned aerial systems (UASs) equipped with sensors allows for substantially reducing the radiation exposure of personnel. An ambient temperature Cs2LiYCl6:Ce3+ (CLYC) elpasolite scintillation sensor for simultaneous gamma and neutron measurements was designed as a user-friendly “plug and fly” module integrated into an octocopter robotic platform. Robot Operating System (ROS) was used to analyze the sensor’s data. The measured CLYC’s energy resolution was < 5% at 662 keV gamma rays; neutron flux was measured using6Li(n,α)t reaction. Time and GPS data were combined with radiation data in the ROS, supporting real time monitoring and assessment tasks, as well as radiation source search missions. Because UASs can be irradiated, radiation damage of the sensor and robot’s electronics was estimated using FLUKA code.

Multidirectional Cylindrical Piezoelectric Force Sensor: Design And Experimental Validation, Ye Rim Lee, Justin Neubauer, Kwang Jin Kim, Youngsu Cha

Mechanical Engineering Faculty Research

A common design concept of the piezoelectric force sensor, which is to assemble a bump structure from a flat or fine columnar piezoelectric structure or to use a specific type of electrode, is quite limited. In this paper, we propose a new design of cylindrical piezoelectric sensors that can detect multidirectional forces. The proposed sensor consists of four row and four column sensors. The design of the sensor was investigated by the finite element method. The response of the sensor to various force directions was observed, and it was demonstrated that the direction of the force applied to the sensor …

Thermo-Mechanical Modeling And The Application Of Coiled Polymer Actuators In Soft Robotics And Biomimetics, Robert Hunt

UNLV Theses, Dissertations, Professional Papers, and Capstones

Coiled polymer actuators (CPA) are a recently discovered smart material. Due to their large tensile stoke and power densities they are often used as actuators or artificial muscles. CPA’s are fabricated from a polymer fiber, typically nylon, mechanically twisted into a coil or coiled around a mandrel and annealed. When heated over the glass transition temperature they can contract, expand or exhibit torsional actuation, depending on the fabrication method and end conditions.

The fabrication and application of CPA is well documented and has made many innovations in the fields of smart materials, soft robotics and the likes. However, there is …

A Comparison Of Two Techniques For Center Of Pressure Measurements, Jessica Deberardinis, Conner Neilsen, Daniel E. Lidstone, Janet S. Dufek, Mohamed B. Trabia

Integrated Health Sciences Faculty Research

Introduction: Force platforms and pressure-measuring insoles are the most common tools used for measuring center of pressure. Earlier studies to assess these instruments suffered from limited sample sizes or an inadequate range of participant foot sizes. The purpose of this study was to propose new methods to extract and calculate comparably accurate center of pressure for the Kistler (R) force platform and Medilogic (R) insoles. Methods: Center of pressure data were collected from 65 participants wearing pressure-measuring insoles (six different sizes). Participants walked over consecutive force platforms for three trials while wearing pressure-measuring insoles within socks. Onset force thresholds and …

Fabrication Of Hard–Soft Microfluidic Devices Using Hybrid 3d Printing, Carlos Ruiz, Karteek Kadimisetty, Kun Yin, Michael G. Mauk, Hui Zhao, Changchun Liu

Mechanical Engineering Faculty Research

Widely accessible, inexpensive, easy-to-use consumer 3D printers, such as desktop stereolithography (SLA) and fused-deposition modeling (FDM) systems are increasingly employed in prototyping and customizing miniaturized fluidic systems for diagnostics and research. However, these 3D printers are generally limited to printing parts made of only one material type, which limits the functionality of the microfluidic devices without additional assembly and bonding steps. Moreover, mating of different materials requires good sealing in such microfluidic devices. Here, we report methods to print hybrid structures comprising a hard, rigid component (clear polymethacrylate polymer) printed by a low-cost SLA printer, and where the first printed …

College Of Engineering Senior Design Competition Spring 2020, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …

The Impact Of Electrostatic Correlations On The Electrokinetics, Elaheh Alidoosti

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this project we are interested in electrokinetics phenomenon (i.e., study of electrical charges in a liquid matter) and focus on three families of this phenomenon, dielectrophoresis, electro-osmosis and streaming current. For the first work, at concentrated electrolytes, the ion-ion electrostatic correlations effect is considered as an important factor in electrokinetics. In this project, we compute, in theory and simulation, the dipole moment for a spherical particle (charged, dielectric) under the presence of an alternating electric field using the modified continuum Poisson-Nernst-Planck (PNP) model by Bazant et al. (Phys. Rev. Lett. 106, 2011) [25]. We investigate the dependency of the …

Remote Radiation Sensing Using Robotic Platforms, Monia Kazemeini

UNLV Theses, Dissertations, Professional Papers, and Capstones

Remote sensing of ionizing radiation has a significant role in waste management, nuclear material management and nonproliferation, radiation safety, and accident response in situations such as the Fukushima nuclear power plant accident. Robotic platforms are able to surpass the number of tasks that could be achieved by humans. With the use of robots, the operator’s radiation exposure can be considerably decreased. Remote sensing allows for the evaluation and monitoring of radiological contamination in hazardous and hard to reach areas and locating radiation sources. In this work, gamma-ray and neutron sensors were integrated onto the unmanned aerial systems (UAS) making it …

Numerical And Experimental Analysis Of Air-Cooled Condensers, Kaipo Kekaula

UNLV Theses, Dissertations, Professional Papers, and Capstones

The scope of this project is to numerically and experimentally dry cooling process in air-cooled condensers (ACCs) designed for concentrated solar power (CSP) applications. This effort is driven by the growing economic and political pressure to reduce water consumption during power generation due to limited water resources in the arid geographic climate of the southwestern United States. A computational approach is used in conjunction with experimental validation to gain a more complete understanding of these systems.

Traditionally research into ACCs have been largely limited to air-side heat transfer modelling as it accounts for a large portion of the total thermal …

Discrete Vortex Modeling Of Aerodynamic Flutter Of A Flat Plate With Damped Oscillations, Emma Chao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerodynamic flutter is the unstable oscillation of a body caused by the interaction of aerodynamic forces, structural elasticity, and inertial effects induced by vortex shedding. Current models of this phenomenon require finite element analysis and extensive computational power and processing time. The purpose of this study was to develop and validate a program that is faster and more efficient than existing approaches by using the discrete vortex method (DVM). By reducing the complexities of flutter to the shedding of vortices in an inviscid model of a two-dimensional flat plate with a torsional spring constant at its center, this phenomenon can …

3d Parametric Hand To Improve Prosthetic Hand Functionality, Maria C. Gerardi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of prosthetics can significantly enhance an individual’s standard of living, not only offering functional advantages but psychological advantages as well. Unfortunately for children with upper limb reduction, options are limited and rejection rates are high due to a multitude of reasons including discomfort and poor functionality. This study proposes a new parametric 3D design model (Parametric Hand) with an adjustable thumb that can be easily manipulated to the uniqueness of an individual. The Parametric Hand was evaluated, both qualitatively and quantitatively, against the Flexy-Hand 2, a commonly used prosthetic hand. The results showed insignificant differences in all testing …

Material Characterization Of Fiber-Reinforced Composite Materials Under Dynamic Loading Condition, Abu Iqbal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fiber reinforced composites are light materials which exhibits great strength and stiffness. They also have good dimensional stability and impact resistance. They reduce mass and improve structural performance, so the demand for fiber reinforced composite materials increases day by day in various industries such as aeronautical, automobile and military. The analysis, design, and optimization of polymer composite materials under static loading conditions are mature fields of study. Many sources are available to find material properties and predict structural response. However, composite materials are often used in extreme environments where they are subject to shock, impact, and blast loading. Efficient computational …

3-D Silk Fibroin Porous Particles Created By The Ouzo Effect For Biomedical Applications, Ashley Nicole Lamb

UNLV Theses, Dissertations, Professional Papers, and Capstones

Due to its high biocompatibility and biodegradability, silk fibroin – produced from

Bombyx mori (B. mori) cocoons – has been at the forefront of research for many

biomedical application formats: hydrogels, films, microspheres, and porous

sponges/scaffolding, to name a few. For drug delivery, in particular, porous particles are

desirable for their large surface area, uniform and tunable pore structure, and high

porosity. This thesis focuses on the fabrication of porous particles from silk fibroin by the

very interesting Ouzo effect. The Ouzo effect, so named because of the Greek

beverage ouzo, describes the phenomenon of an ethanol + anethole oil …

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …

Ambient Temperature Dependence Of Air-Cooled Condenser Performance And Parameters, Alexander Darr Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Thermoelectric power generation uses 38% of total fresh water withdrawals and majority of that water is used during steam condensation. Air-cooled condensers are an alternative to water-cooled condensers for power generation. Ambient air temperature affects the performance of air-cooled condensers. A small air-cooled condenser was run under the ambient air temperature extremes of Las Vegas in order to examine the system performance and air-side heat transfer parameters. Three different sets of tubes with different surface areas and geometries were studied. The condenser is equipped with several air velocity sensors, thermocouples and thermistors to measure the conditions to develop the air-side …

Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

This numerical study investigates the thermal performance of internally grooved tubes used in heat exchangers. In order to enhance the performance of heat exchangers, turbulence promoters are inserted along the streamwise flow. The use of inserts, grooves, and augmentations along the axial length of the tube creates disturbances that improve the overall heat transfer due to enhanced fluid mixing and greater surface contact boundary walls. However, the implementation of tube wall augmentations creates an increase in pressure drop across the tube which must be compensated for with additional pumping power for the working fluid. Therefore, in order to analyze the …

College Of Engineering Senior Design Competition Fall 2019, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …

Dual Mode Radiation Sensor For Uas Platforms, Alexander Barzilov, Monia Kazemeini

Mechanical Engineering Faculty Research

Remote sensing technologies are important for radiation safety and environmental security applications. A dual-mode Cs2LiYCl6:Ce3+ (CLYC) sensor was developed for simultaneous neutron measurements and gamma-ray spectroscopy. To keep users away from hazardous areas, an unmanned aerial system was used as a mobile sensor platform. The sensor was integrated into a multicopter platform as a ‘plug and fly’ component allowing deployment in the field conditions. The photon energy resolution of the CLYC sensor was measured as less than 5% at 662 keV. The detection of neutrons was achieved via 6Li(n,α)t reaction. The sensor’s signal communication and data fusion were programmed using …

Design And Modeling Of A New Biomimetic Soft Robotic Jellyfish Using Ipmc-Based Electroactive Polymers, Zakai J. Olsen, Kwang J. Kim

Mechanical Engineering Faculty Research

Smart materials and soft robotics have been seen to be particularly well-suited for developing biomimetic devices and are active fields of research. In this study, the design and modeling of a new biomimetic soft robot is described. Initial work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic design. In particular, the capability of the model to account for the mass and geometry of the robot design has been added for better …

A Soft-Robotic Harbor Porpoise Pectoral Fin Driven By Coiled Polymer Actuators As Artificial Muscles, Robert Hunt, Sarah Trabia, Zakai Olsen, Kwang Kim

Mechanical Engineering Faculty Research

Biomimicry is an approach in science and engineering to overcome human challenges by designing materials and systems modeled after nature. Selected applications of biomimicry include catheters, hearing devices, and artificial appendages such as arms, legs, and fingers. The inspiration for this study is the hydrofoil-like structured pectoral fin of the harbor porpoise whale that is ultimately useful for studying fluid-structure interactions, drag, lift, and laminar-to-turbulent transitions. The pectoral fin is fabricated by manipulating computed tomography (CT) scans into 3D models using Simpleware ScanIP and post-processed in Autodesk for printing. An array of thermally driven coiled polymer actuators (CPA) fabricated from …

Silica-Coated Metallic Nanoparticle-Based Hierarchical Super-Hydrophobic Surfaces Fabricated By Spin-Coating And Inverse Nanotransfer Printing, Shengjie Zhai, Hui Zhao

Mechanical Engineering Faculty Research

By combining spin coating and inverse nanotransfer printing, silica-coated gold nanoparticles are patterned onto polydimethylsiloxane (PDMS) superhydrophobic surfaces to form a hierarchical structure. A layer of nanoparticles is spin-coated on a flat silicon substrate serving as the stamp, which is then transferred to the raised regions of PDMS surfaces. Our inverse nanotransfer printing is in contrast to the standard nanotransfer printing, which transfers metal from the raised regions of a stamp to a flat PDMS surface. The fabricated hierarchical surface exhibits a higher contact angle and delays the Cassie-Wenzel transition during evaporation of a sessile droplet, indicating an improvement of …