Mechanical Engineering Commons^™

Experimental Investigation And Numerical Simulation Of A Copper Micro-Channel Heat Exchanger With Hfe-7200 Working Fluid, Eric Borquist

Doctoral Dissertations

Ever increasing cost and consumption of global energy resources has inspired the development of energy harvesting techniques which increase system efficiency, sustainability, and environmental impact by using waste energy otherwise lost to the surroundings. As part of a larger effort to produce a multi-energy source prototype, this study focused on the fabrication and testing of a waste heat recovery micro-channel heat exchanger. Reducing cost and facility requirements were a priority for potential industry and commercial adoption of such energy harvesting devices. During development of the micro-channel heat exchanger, a new fabrication process using mature technologies was created that reduced cost, …

Contribution Of Fiber Undulation To Mechanics Of Three-Dimensional Collagen-I Gel, Shengmao Lin, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The collagen-I gel is extensively used as a scaffold material in tissue engineering due to its ability to mimic the extracellular matrix (ECM). In this study, the mechanics of collagen-I gel is investigated using a numerical model of three-dimensional collagen network. The resulted mechanical behavior was validated against the published experimental data. Results illustrated that fiber alignment was dominated in the low strain region, and its transition to stretching dominated phenomena at higher strain led to the strain stiffening of collagen gel. The collagen undulation at the microscopic level was found to delay the initiation of strain stiffening

A Comparison Of Microstructure And Uniaxial Compressive Response Of Ice-Templated Porous Alumina Scaffolds Fabricated From Two Different Particle Sizes, Nikhil D. Dhavale

Mechanical & Aerospace Engineering Theses & Dissertations

Development of bio-inspired highly porous (>50 vol.%) cellular ceramics is crucial to meet the demand of high-performance lightweight and damage-tolerant materials for a number of cutting-edge applications including impact energy absorption, biomedical implants, and energy storage. A key design feature that is observed in many natural materials (e.g., nacre, bamboo, wood, etc.) is the presence of hierarchical microstructure that results in an excellent synergy of various material properties, which are otherwise considered as mutually exclusive in current paradigm of materials design. To this end, development of multilayered, interconnected and anisotropic cellular ceramics could benefit the aforementioned applications. However, mimicking …

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

Two Compact Jet Engine Simulator (CJES) units were designed for integrated wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. To meet the 5.8% scale of the HWB model, Ultra Compact Combustor technology from the Air Force Research Laboratory was used. The CJES units were built and integrated with a control system in the NASA Langley Low Speed Aero acoustic Wind Tunnel. The combustor liners, plug—vane and flow conditioner components were built in-house at Langley Research Center. The operation of the CJES units was mapped and fixes found for combustor instability tones and rig flow noise. The original …

Carbon Nanotube Based Groundwater Remediation: The Case Of Trichloroethylene, Kshitij C. Jha, Zhuonan Liu, Hema Vijwani, Mallikarjuna Nadagouda, Sharmila M. Mukhopadhyay, Mesfin Tsige

Mechanical and Materials Engineering Faculty Publications

Adsorption of chlorinated organic contaminants (COCs) on carbon nanotubes (CNTs) has been gaining ground as a remedial platform for groundwater treatment. Applications depend on our mechanistic understanding of COC adsorption on CNTs. This paper lays out the nature of competing interactions at play in hybrid, membrane, and pure CNT based systems and presents results with the perspective of existing gaps in design strategies. First, current remediation approaches to trichloroethylene (TCE), the most ubiquitous of the COCs, is presented along with examination of forces contributing to adsorption of analogous contaminants at the molecular level. Second, we present results on TCE adsorption …

Industrial Robot Trajectory Stiffness Mapping For Hybrid Manufacturing Process, Z. Wang, R. Liu, X. Chen, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn

Mechanical and Aerospace Engineering Faculty Publications

Automatic commercial ice-making machines that produce a batch of cube ice at regular intervals are known as “cubers." Such machines are commonly used in food service, food preservation, hotel, and health service industries. The machines are typically rated for the weight of ice produced over a 24-hour period at ambient air temperatures of 90°F and water inlet temperature of 70°F.

These cubers typically utilize an air-cooled, vapor-compression cycle to freeze circulating water flowing over an evaporator grid. Once a sufficient amount ice is formed, a valve switches to enable a harvest mode, where the compressor’s discharge gas is routed into …

Automated Measurement Of Fracture Callus In Radiographs Using Portable Software, Stephen M. Porter, Hannah L. Dailey, Katharine A. Hollar, Karina Klein, James A. Harty, Trevor J. Lujan

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The development of software applications that assist the radiographic evaluation of fracture healing could advance clinical diagnosis and expedite the identification of effective treatment strategies. A radiographic feature regularly used as an outcome measure for basic and clinical fracture healing research is new bone growth, or fracture callus. In this study, we developed OrthoRead, a portable software application that uses image-processing algorithms to detect and measure fracture callus in plain radiographs. OrthoRead utilizes an optimal boundary tracking algorithm to semi-automatically segment the cortical surface, and a novel iterative thresholding selection algorithm to then automatically segment the fracture callus. The software …

Analysis And Synthesis Of A Planar Reconfigurable Mechanism With A Variable Joint, Peter William Malak

Master's Theses (2009 -)

Currently, there is a demand for mechanisms with variable topology that can perform multiple tasks with the least amount of actuators. These devices have the ability to provide numerous motion profiles within one device. In the following thesis, a specific planar reconfigurable mechanism with a kinematic reconfigurable joint was mathematically modeled. This mechanism functions as a RRRP mechanism in one configuration and as a RRRR in the other and is known as a RRRR-RRRP Mechanism. The kinematics and kinetics of the RRRR-RRRP Mechanism were analyzed with a Lagrangian approach. The models are simulated and verified using a trajectory planner and …

Constrained-Energy Cross-Well Actuation Of Bistable Structures, Masoud Zarepoor

Mechanical & Aerospace Engineering Theses & Dissertations

Bistable structures have two stable equilibrium positions and can be utilized to maintain a specific static shape with no energy consumption. This dissertation focuses on the minimum required energy for performing snap-through of a bistable structure. Snap-through is the motion of a bistable structure from one stable equilibrium position to the other. This research uses the Duffing-Holmes equation as a one-degree-of-freedom representative model of a bistable structure, and this nonlinear equation is solved to calculate the required energy for cross-well oscillation. The research identifies several unique features of the response of a bistable system subjected to force and energy constraints. …

Carbon Deposition During Oxygen Production Using High Temperature Electrolysis And Mitigation Methods, Timothy Adam Bernadowski

Mechanical & Aerospace Engineering Theses & Dissertations

Carbon dioxide in the Martian atmosphere can be converted to oxygen during high temperature electrolysis for use in life-support and fuel systems on manned missions to the red planet. During electrolysis of carbon dioxide to produce oxygen, carbon can deposit on the electrolysis cell resulting in lower efficiency and possibly cell damage. This would be detrimental, especially when the oxygen product is used as the key element of a space life support system. In this thesis, a theoretical model was developed to predict hazardous carbon deposition conditions under various operating conditions within the Martian atmosphere. The model can be used …

The Controlled Human Gyroscope, Randy Claude Arjunsingh

Theses and Dissertations

The objective of this thesis was to design an adaptive rotational motion simulator capable of replicating the attitudes of spacecrafts and aircrafts, while avoiding gimbal lock. Flight motion simulators are currently used for flight training and research, but there are many limitations to these existing systems. This thesis presents a low-cost design for a rotational motion platform titled, ‘The Controlled Human Gyroscope’. It uses a 4-axis system instead of the conventional 3-axis system to avoid gimbal lock and prevent the unnecessary motion of the user. The Human Gyroscope features unlimited rotation about the roll, pitch and yaw axes regardless of …

Numerical Modeling Of Soy Biodiesel To Maximize Engine Power And Efficiency While Minimizing Pollutant Emissions, Ehsan Tootoonchi

Theses and Dissertations

Biodiesel is a renewable fuel that can help to reduce dependence on foreign petroleum and to help control the negative environmental effects of combustion engines. This work develops a numerical model for soy biodiesel combustion in diesel engine applications. A comprehensive breakup model for diesel and biodiesel combustion calculations using the KIVA- 3V is presented. The primary breakup model calculates the outcome of the initial breakup stage using flow conditions, nozzle geometry, and liquid fuel characteristics, and assigns the Sauter Mean Radius (SMR) values to injecting droplets. The Kelvin-Helmholtz/Rayleigh-Taylor(KH-RT) model acts as the secondary model to break up injected particles. …

On The Importance Of Displacement History In Soft-Body Contact Models, Jonathan A. Fleischmann, Radu Serban, Dan Negrut, Paramsothy Jayakumar

Mechanical Engineering Faculty Research and Publications

Two approaches are commonly used for handling frictional contact within the framework of the discrete element method (DEM). One relies on the complementarity method (CM) to enforce a nonpenetration condition and the Coulomb dry-friction model at the interface between two bodies in mutual contact. The second approach, called the penalty method (PM), invokes an elasticity argument to produce a frictional contact force that factors in the local deformation and relative motion of the bodies in contact. We give a brief presentation of a DEM-PM contact model that includes multi-time-step tangential contact displacement history. We show that its implementation in an …

Advanced Technologies For Sustainable Systems, Hesham Safwat

Mechanical Engineering

No abstract provided.

Comparison Of Airfoil Precomputational Analysis Methods For Optimization Of Wind Turbine Blades, Ryan Barrett, Andrew Ning

Faculty Publications

The objective of this research was to develop and compare various airfoil precomputational parameterization and analysis techniques for aerostructural optimization of wind turbine blades. The airfoils along the blade were added as optimization design variables through pre-computational parameterization methods using thickness-to-chord ratios and blended airfoil family factors. The airfoils' aerodynamic performance was analyzed with three methods of increasing fidelity: a panel method (XFOIL), Navier-Stokes based computational fluid dynamics (RANS CFD), and wind tunnel data. The optimizations minimized mass over annual energy production (m/AEP) and thereby approximated the minimization of cost of energy. The results were compared to the NREL 5-MW …

2015 Electric Vehicle Market Summary And Barriers, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

The object of this research report is to present the current market status of plug-in-electric vehicles (PEVs) and to predict their future penetration within the world and U.S. markets. The sales values for 2015 show that China leads in yearly sales at 214,283 (triple increase for 2014) followed by Western Europe at 184,500 vehicles sold. The U.S. is third at 115,262 followed by Japan at 46,339 vehicles. These four countries comprise 95% of the global sales market. The world total of EV sales for 2015 is estimated to be 565,668 up from 315,519 in 2014. This data also shows that …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• Project Lead the Way (PLTW) Hosted by Mechanical Engineering

Numerical Modeling Of Heat Transfer And Material Flow During Friction Extrusion Process, Hongsheng Zhang

Theses and Dissertations

Friction extrusion process is a novel manufacturing process that converts low-cost metal precursors (e.g. powders and machining chips) into high-value wires with potential applications in 3D printing of metallic products. However, there is little existing scientific literature involving friction extrusion process until recently. The present work is to study the heat transfer and material flow phenomena during the friction extrusion process on aluminum alloy 6061 through numerical models validated by experimental measurements.

The first part is a study of a simplified process in which flow of a transparent Newtonian fluid in a cylindrical chamber caused by frictional contact with a …

Study Of Friction Extrusion And Consolidation, Xiao Li

Theses and Dissertations

Friction extrusion and consolidation was invented by The Welding Institute (Cambridge, UK) in the early 1990’s. It is related to simple extrusion processes with the primary difference being that the extrusion die rotates about the extrusion axis and the die is required to impart substantial deformation to the initially, finely divided charge (like metal waste or chips) in order to consolidate it prior to extrusion. It can produce high quality wire and fully consolidated bulk material from low-cost precursors like metal chips or powders. The advantages lie in that it is a direct method to recycle metal chips or scraps …

Application And Analysis Of Asymmetrical Hot And Cold Stimuli, Ahmad Manasrah

USF Tampa Graduate Theses and Dissertations

The human body has a unique mechanism for perceiving surrounding temperatures. When an object is in contact with the skin, we do not feel its temperature. Instead, we feel the temperature change that is caused on our skin by that object. The faster the heat is transferred, the more intense the thermal sensation is. In this dissertation, a new dynamic thermal display method, where different rates of warm and cold are applied on the skin to generate a unique sensation, is presented. The new method can be related in a wide range of applications including thermal haptics and virtual reality. …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• NSF RET Grant Awarded to Dr. Soloiu

The Development Of A Prosthetic Training Software For Upper Limb Amputees, Tyler Kayne Sullins

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to develop an intuitive software that aids in the field of prosthetic training and rehabilitation by creating an individualized visualization of joint angles. This software is titled “the prosthetic training software (PTS) for individualized joint angle representation”, and it enables the individualized portrayal of predicted or pre-recorded joint angles. The PTS is an intuitive program for clinicians and prosthesis users that produces an animation of a virtual avatar reflecting the user’s segment lengths and amputation for rehabilitation and training purposes.

The PTS consists of a graphical user interface (GUI) and a 3D visualization of …

Dynamic Simulation And Analysis Of Fsae Racer For Development Of Stability Control System, Stone D. Williford

Honors College Theses

Using Adams/Car software, a computer model of Georgia Southern University’s 2016 Formula Society of Automotive Engineers (FSAE) racecar was developed with the purpose of researching vehicle stability under dynamic conditions. Previous research in this field of study has been conducted to verify that Adams/Car simulations provide accurate results using data acquisition systems, so the major work for the current research has been to create an updated version of the vehicle designed and fabricated by Eagle Motor Sports. With this new model, vehicle roll, and pitch data as well as vehicle traction were collected during dynamic simulations. The overall goal for …

Small-Scale And Large-Scale Interventions To Improve [State] Student’S College Readiness, Virgil U. Pierce, Javier A. Kypuros, Shirley J. Mills

Mechanical Engineering Faculty Publications and Presentations

We are conducting two interventions aimed at improving entering students’ college readiness and mathematics placement. The small-scale intervention is aimed at working with students on the university campus. Students who are targeted have high school course work indicating that they have experience in Calculus or Pre-Calculus courses, but whose placement tests have not indicated they are ready for Calculus. At our institution this is a significant number of students and the goal of the project is to develop methods to address and accelerate students in this category. The course design, to take advantage of the students’ prior experience, emphasizes practice …

Integrating E-Learning Modules Into Engineering Courses To Develop An Entrepreneurial Mindset In Students, Nadiye O. Erdil, Ronald S. Harichandran, Jean Nocito-Gobel, Maria-Isabel Carnasciali, Cheryl Q. Li

Engineering and Applied Science Education Faculty Publications

Engineering graduates who will be leaders in today’s rapidly changing environment must possess an entrepreneurial mindset and a variety of professional skills in addition to technical knowledge and skills. An entrepreneurial mindset applies to all aspects of life, beginning with curiosity about our changing world, integrating information from various resources to gain insight, and identifying unexpected opportunities to create value. The Kern Entrepreneurial Engineering Network (KEEN) defines curiosity, connections and creating value as three core components of an entrepreneurial mindset. These 3Cs coupled with associated engineering skills forms KEEN’s entrepreneurial mindset framework. An entrepreneurial mindset enables engineers to develop sound …

Preliminary Assessment Of And Lessons Learned In Pitch: An Integrated Approach To Developing Technical Communication Skills In Engineers, Nadiye O. Erdil, Ronald S. Harichandran, Michael A. Collura, Jean Nocito-Gobel, David J. Adams, Amanda Simson

Mechanical and Industrial Engineering Faculty Publications

The Project to Integrate Technical Communication Habits (PITCH) has been implemented across seven engineering and computer science undergraduate programs starting in fall 2012. The overarching goal of PITCH is to develop written, oral and visual communication skills and professional habits in engineering students. PITCH activities begin in the very first semester and are reinforced and extended through all four years of each program. After three years of progressively more extensive development and deployment, a preliminary assessment of student writing over their first three years in programs was performed. In May 2016 the first cohort of students will have completed the …

All Active All The Time? What Are The Implications Of Teaching A Traditional Content-Rich Machine Components/Mechanical Systems Design Course Using Active Learning?, James M. Widdmann, Peter Schuster

Mechanical Engineering

This paper examines the use of research-proven Active Learning techniques to transform the teaching of a traditional Machine Components/Mechanical Systems Design class. We know from research in Active learning that use of these methods can often lead to greater conceptual understanding and greater engagement of the students with engineering course materials, yet a common concern among engineering faculty is that the adoption of Active learning techniques will not allow the full breadth and depth of traditional content coverage. In this work, the authors reimagined one of the most content-heavy courses in a traditional Mechanical Engineering curriculum by including many Active …

Development And Use Of The Energy Model Of A Research And Demonstration House With Advanced Design Features, Nelson Fumo, Vicente Bortone

Mechanical Engineering Faculty Publications and Presentations

Advances on manufacturing processes and the use of new materials are increasing the efficiency and reducing the cost of energy efficient and renewable energy technologies to a point that their deployment will reach desired levels for the sake of energy security and environmental concerns. Along these advances, the demonstration of the cost-effectiveness of this technology is vital to educate people and promote deployment of these technologies. In this sense, at the University of Texas at Tyler, two research and demonstration houses were built. House #1 is a conventional design with some advanced features, and House #2 has more advanced design …

Effects Of Electrode Off Centre On Trapped Thickness-Shear Modes In Contoured At-Cut Quartz Resonators, Junjie Shi, Cuiying Fan, Minghao Zhao, Jiashi S. Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We investigated thickness-shear vibrations of a contoured, AT-cut quartz resonator with a pair of electrodes displaced from the resonator centre. The scalar differential equations by Stevens and Tiersten for thickness-shear vibrations of electroded and unelectroded quartz plates were employed. Based on the variational formulation of the scalar differential equations established in a previous paper and the variation-based Ritz method with trigonometric functions as basis functions, free vibration resonance frequencies and trapped thickness-shear modes were obtained. The effects of the electrode off centre on resonance frequencies and mode shapes were examined. When the electrode off centre is about one hundredth of …