Mechanical Engineering Commons^™

Analysis Of Bolted Joints Under Medium And High Impact Loading, Deepak Somasundaram

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding the transient behavior of structures with bolted joints when subjected to medium and high shock or impact loads can be challenging due to their nonlinear response, which is induced by the complex interactions between the bolts and the structure. While few researchers have considered shock transmission through bolted joints at low impact loading, there are little literature on shock transmission through bolted joints under high loading conditions. Low impact loading condition generally excites the lower order frequencies but under high impact loading higher order frequencies are excited. Typical factors that affect the response of a bolted joint include, preload …

Study Of Water Transport Phenomena On Cathode Of Pemfcs Using Monte Carlo Simulation, Karn Soontrapa

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation deals with the development of a three-dimensional computational model of water transport phenomena in the cathode catalyst layer (CCL) of PEMFCs. The catalyst layer in the numerical simulation was developed using the optimized sphere packing algorithm. The optimization technique named the adaptive random search technique (ARSET) was employed in this packing algorithm. The ARSET algorithm will generate the initial location of spheres and allow them to move in the random direction with the variable moving distance, randomly selected from the sampling range, based on the Lennard-jones potential of the current and new configuration. The solid fraction values obtained …

Simulations Of Interfacial Electrokinetics With Applications To Microfluidic Systems, Sebastian Uppapalli

UNLV Theses, Dissertations, Professional Papers, and Capstones

Electrokinetics plays an important role in facilitating fluid transport and particle manipulation in microfluidic systems. This dissertation studies the mechanics of electrokinetic phenomena for microscale particles and drops. The work aims to increase the understanding of complex electrokinetic phenomena for applications in Lab-on-Chip technology, assembly of colloidal particles and two-phase flow sensing. The standard model consisting of the Poisson-Nernst-Planck equations is used to study the electric double layer polarization of charged dielectric particles and channel wall which plays a major role in control and manipulation of colloidal particles and understanding of electrohydrodynamic flow field.

The cases of polarization of "soft" …

Simulation Of Thermal Transit-Time Flow Meter For High Temperature, Corrosive And Irradiation Environment, Elaheh Alidoosti

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the environments of high temperature (300o C - 1000o C), corrosive and even irradiation application, the challenges of providing reliable and accurate flow rate measurement is significant. In comparing with many other existing technologies for normal operation environments, correlated thermal transit-time flow meter show its advantages of resolving the challenges encountered in those harsh conditions. The correlated thermal signals can be detected by two separated thermal sensors (for example, thermocouples) in series alignment along the pipe, and derive the flow rate. It was evaluated to have accurate measurement for small pipe at slow fluid speed. In the higher flow …

Plastic Deformation Of Steel Plates Under High Impact Loading, Brendan O'Toole

NSTec UNLV Symposium

• UNLV Two-stage Light Gas Gun
• Experimental Measurements
• Physical Results of Impact on Target Plates
• Research Objectives
• Computational Analysis Methods
• Material Models used in Computational Analysis
• Simulation Comparison: Crater and Deformation
• Simulation Comparison: Free Surface Velocity
• High Speed Video of Experiments
• Microscopy of Failure Surface: Is Phase Change an Issue?
• Electron Back Scatter Diffraction (EBSD) of Failure Surfaces
• On-going Plans and Future Work

Ambulatory Extracorporeal Arterioveous Co2 Removal Via Subclavian Vessels, Alejandra Macias, Alvaro Rojas-Pena

McNair Poster Presentations

Lung transplantation is the last recourse for patients with severe respiratory failure. However, transplantable lungs do not keep up with the demand, and 15.4% of patients die awaiting transplant. An alternative therapy is extracorporeal life support (ECLS), which uses a pump and an oxygenator to serve as a bridge to transplant. However, this technology limits ambulation and requires ICU care. This novel study implements pumpless arteriovenous (AV) ECLS technology to remove CO2 via the subclavian vessels, providing respiratory support and hypercapnia (excessive CO2 retention) sympton relief for patients while allowing ambulation.

College Of Engineering Senior Design Competition Fall 2013, 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 …

Computer-Based Stereoscopic Parts Recognition For Robotic Applications, Ahmad A. Fayed

UNLV Theses, Dissertations, Professional Papers, and Capstones

Most of robotic handling and assembly operations are based on sensors such as range and touch sensors. In certain circumstances, such as in the presence of ionizing radiation where most customary sensors will degrade over time due to radiation exposure, these sensors won't function properly. Utilizing two or more cameras (stereo vision) located outside the target zone and analyzing their images to identify location and dimensions of parts within the robot workspace is an alternative for using sensors. Object Recognition is affected by the light condition which oftentimes causes the gray-scale or red, green, and blue values to have a …

Experimental And Finite Element Studies Of Shock Transmission, Eldon Jerry Goddard

UNLV Theses, Dissertations, Professional Papers, and Capstones

Composite materials are more widely used today in engineering products than ever before. Shock transmission in jointed composite sections needs to be investigated to understand the affect of composite materials on the dynamic response of the system. There exists limited published work on transient shock propagation through composite sections. The aim of this study is to analyze the transient behavior of joints in composite materials subjected to low impact loads and to develop a computational model that provides an improved physics based shock model. The jointed connection will be investigated experimentally and using Finite Element Analysis (FEA). The bolted joint …

Numerical Modeling Of Heat Pipe Radiator And Fin Size Optimization For Low And No Gravity Environments, Virginia Ruth Bieger

UNLV Theses, Dissertations, Professional Papers, and Capstones

A heat-pipe radiator element has been designed and modeled to study the efficiency of heat transfer for low and no gravity environments, like in lunar environments. The advantages of using heat pipe includes the significant weight reducing and heat transfer efficiency. The heat transfer can be enhanced by the use of condenser sections with attached fins.

A series of various geometries of solid fins and heat pipes with and without fins were modeled using FLUENT®. This was done to determine the validity of using a heat pipe in lieu of a solid fin projection. A heat pipe had a 25 …

3d Modeling And Design Optimization Of Rod Shaped Ionic Polymer Metal Composite Actuator, Siul A. Ruiz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer-metal composites (IPMCs) are some of the most well-known electro-active polymers. This is due to their large deformation provided a relatively low voltage source. IPMCs have been acknowledged as a potential candidate for biomedical applications such as cardiac catheters and surgical probes; however, there is still no existing mass manufacturing of IPMCs. This study intends to provide a theoretical framework which could be used to design practical purpose IPMCs depending on the end users interest.

This study begins by investigating methodologies used to develop quantify the physical actuation of an IPMC in 3-dimensional space. This approach is taken in …

College Of Engineering Senior Design Competition Spring 2013, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

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. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …

Predicting The Performance Of A Solar Domestic Water Heating System With Evacuated Tube Collectors And Hydronic Radiant Flooring, Kimberly Nicole Hammer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Residential solar thermal system installations have been significantly increasing in the last decade and there exists limited resources for reasonably predicting the performance of those systems. A simulated model is developed in MATLAB® and used to predict the performance of a solar domestic water heating system. In the simulated system, hot water is generated using evacuated tube solar collectors and stored in a domestic hot water storage tank, which utilizes immersed coil heat exchangers. The system is designed to provide hydronic radiant floor heating to its occupants based on the heat loss of a building energy model for an energy-efficient …

Supersonic Turbine Cascade Studies Using Computational Fluid Dynamics And Water Table Experiments, Shelby E. Nelson

Honors College Theses

Design engineers use a variety of tools to perform calculations and to aid in the design process. For example, engineers designing gas turbines, specifically the aerodynamicists, use a combination of hand calculations, experimental data, and complex numerical codes to simulate air flow around each blade. Aerodynamicists designing gas turbines must predict the locations of the shocks to locate inefficiencies in the flow. In this thesis, three methods of calculating the shock angles are compared: analytical, experimental, and computational. Three different airfoil shapes are tested: a rectangular flat plate, a supersonic diamond, and a turbine airfoil. Cascade tests of the airfoil …

Investigation Of Peak Load Reduction Strategies In Residential Buildings In Cooling Dominated Climates, Fady Atallah

UNLV Theses, Dissertations, Professional Papers, and Capstones

This investigation of peak load reduction strategies in residential buildings contributes to the global international efforts in reducing energy consumption and is related directly to energy efficiency in residential and commercial buildings. Work reported here involves computer aided building energy simulation of energy efficient and non-energy efficient residential homes coupled with empirical energy consumption data gathered from monitoring an array of energy efficient residential homes. The latter have been implemented for peak load reduction strategies. In addition non-energy efficient residential homes have been monitored to compare performance to the energy efficient homes. This study demonstrates the crucial importance of energy …

Design And Testing Of Novel Mouthguard With Intermediate Nitinol And Foam Layers, Adam Kessler

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is the aim of this study to investigate a novel mouthguard design that incorporates the use of a nickel-titanium (Nitinol) layer and thin foam layer in addition to EVA layers. It is thought that the Nitinol layer can distribute the force of an impact and that the thin foam layer may absorb this distributed force better than a solid EVA mouthguard of the same thickness. Rectangular, flat coupons representative of several mouthguard configurations were constructed for testing using an instrumented drop-weight impact tower. The coupon configurations include a control made of laminated EVA, a group of laminated EVA and …

Closed Loop Control Of A Cylindrical Tube Type Ionic Polymer Metal Composite (Ipmc), Benjamin Mead

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this research is to provide a framework for the integration of tube type, cylindrical Ionic Polymer Metal-Composite (IPMC) into conventional devices. IPMCs are one of the most widely used types of electro-active polymer actuator, due to their low electric driving potential and large deformation range. For this research a tube type IPMC was investigated. This IPMC has a circular cross section with four separate electrodes on its surface and a hole through the middle. The four electrodes allow for biaxial bending and accurate control of the tip location. One of the main advantages of using this type …

Hydraulic And Thermal Performances Of A High Temperature Ceramic Plate-Fin Heat Exchanger (Pfhe), Vijaisri Nagarajan, Yitung Chen, Qiuwang Wang, Ting Ma

College of Engineering: Graduate Celebration Programs

• Numerical analysis was carried for novel configuration of high temperature PFHE
• Fluid flow and heat transfer properties were studied for various fin configurations
• Ripsaw fin design with thickness of 0.05 mm gives maximum heat transfer with less pressure drop and friction factor
• Validation and parametric study were carried out for all fin configurations

Numerical Characterization Of The Hydrodynamics And Thermal Behavior Of Air Flow In A "Flex-Duct" Air Distribution System, Samad Gharehdaghi, Samir Moujaes

College of Engineering: Graduate Celebration Programs

The aim of this research paper is to compute the hydrodynamic and heat transfer characteristics of the air flow inside a flexible duct used for residential/small commercial buildings. Various new information which manufacturers do not provide usually are produced numerically among which heat transfer coefficient, needed for estimating heat loss, is a principal one. Circulation zones in depressions are found to exist. It is shown that these regions act as an insulator and decrease the heat loss along the duct. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal …

Vulnerability Of Progressive Collapse In Reinforced Concrete Flat-Plate Buildings, Jinrong Liu

College of Engineering: Graduate Celebration Programs

• Progressive collapse is the spread of initial local failure, causing partial or
  even total collapse of a building.
• Flat plate structure is widely used for office and residential buildings.
• There is a large inventory of older flat plate building without continuous slab bottom reinforcement through columns.
• Limited knowledge exists regarding the risk of disproportionate collapse in
  older flat-plates under sudden column removal during abnormal events.
• Reliable mechanical model is needed for structural evaluation.

Mono-Sized Sphere Packing Algorithm Development Using Optimized Monte Carlo Technique, Karn Soontrapa, Yitung Chen

College of Engineering: Graduate Celebration Programs

In this research, fuel cell catalyst layer was developed using the optimized sphere packing algorithm. An optimization technique named adaptive random search technique (ARSET) was employed in this packing algorithm. The ARSET algorithm will generate the initial location of spheres and allow them to move in the random direction with the variable moving distance, randomly selected from the sampling range (a), based on the Lennard–Jones potential and Morse potential of the current and new configuration. The solid fraction values obtained from this developed algorithm are in the range of 0.610–0.624 while the actual processing time can significantly be reduced by …

Lanthanum Halide Nanoparticle Scintillators For Nuclear Radiation Detection, Paul Guss, Ronald Guise, Ding Yuan, Sanjoy Mukhopadhyay, Robert O’Brien, Daniel Robert Lowe, Zhitao Kang, Hisham Menkara, Vivek V. Nagarkar

Mechanical Engineering Faculty Research

Nanoparticles with sizesscintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

Transparent Actuator Made With Few Layer Graphene Electrode And Dielectric Elastomer, For Variable Focus Lens, Taeseon Hwang, Hyeok-Yong Kwon, Joon-Suk Oh, Jung-Pyo Hong, Seung-Chul Hong, Youngkwan Lee, Hyouk Ryeo Choi, Kwang J. Kim, Mainul Hossain Bhuiya, Jae Do Nam

Mechanical Engineering Faculty Research

A transparent dielectric elastomer actuator driven by few-layer-graphene (FLG) electrode was experimentally investigated. The electrodes were made of graphene, which was dispersed inN-methyl-pyrrolidone. The transparent actuator was fabricated from developed FLG electrodes.The FLG electrode with its sheet resistance of 0.45 kΩ/sq (80 nm thick) was implemented to mask silicone elastomer. The developed FLG-driven actuator exhibited an optical transparency of over 57% at a wavenumber of 600 nm and produced bending displacement performance ranging from 29 to 946 μm as functions of frequency and voltage. The focus variation was clearly demonstrated under actuation to study its application-feasibility in …

College Of Engineering Senior Design Competition Fall 2012, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

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. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …

Plasma Test On Industrial Diamond Powder In Hydrogen And Air For Fracture Strength Study, Rohit Asuri Sudharshana Asuri Sudharshana Chary

UNLV Theses, Dissertations, Professional Papers, and Capstones

Diamonds are the most precious material all over the world. Ever since their discovery, the desire for natural diamonds has been great; recently, the demand has steeply increased, leading to scarcity. For example, in 2010, diamonds worth $50 billion were marketed. This increased demand has led to discovering alternative sources to replace diamonds. The diamond, being the hardest material on earth, could be replaced with no other material except another diamond. Thus, the industrial or synthetic diamond was invented. Because of extreme hardness is one of diamond's properties, diamonds are used in cutting operations. The fracture strength of diamond is …

The Design And Testing Of A Solar Autoclave With Broad Spectrum Sterilization Capabilities, Sarah S. Trabia

Honors College Theses

Energy is difficult to come by in developing countries and this interferes with the ability of doctors to provide good healthcare to their patients. Without decent sterilization, patients can become infected and diseases can spread throughout hospitals. This study involves designing a solar autoclave for developing countries that is as efficient as electrical autoclaves. The design is intended to not require any electrical input and to be affordable to those who cannot afford advanced medical equipment. Once the solar autoclave is designed, it will be tested to determine if it can sterilize equipment against a variety of different bacteria, including …

College Of Engineering Senior Design Competition Spring 2012, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

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. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to source …

College Of Engineering Senior Design Competition Spring 2018, 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 …

A Refreshable And Portable E-Braille System For The Blind And Visually Impaired, Mohammad Yousef Saadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this research is to design an affordable Braille tactile display that is wearable, refreshable, and portable. The device is intended to be used as an output device that can playback stored media. It can be also incorporated with current Braille reading technologies. The device will control both the electrical and mechanical stimulations to optimize the sensation and ensure extended use of the device. This work is concerned mainly with the mechanical aspects of the design.

This research proposed the development of a finger-wearable, scanning-style electric stimulation based (electrotactile) Braille display with sensing and adaptive rendering/actuation functions for …

Buffering Pv Output During Cloud Transients With Energy Storage, Yacouba Moumouni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis …