Mechanical Engineering Commons^™

Sustainability For Die Manufacturing: Comparative Study Of Wedm And Milling, Matthew S. Kalus

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Sustainability is more important in today's culture due to the increasing demand for a more eco-friendly society. Concentrations in minimizing and reducing environmental impacts, energy and natural resources have been forthcoming in industry. The tool, mold and die industries are the most well known industries that machine harder materials using mills and WEDM. The objective of this thesis was to compare the sustainability differences in both of these machines utilizing the accepted standards for evaluating the manufacturing process performance for sustainability. These standards include the evaluation of the process parameters, raw materials, power, tools and fluids which all contribute to …

A Study Of Hdpe In High Pressure Of Hydrogen Gas—Measurement Of Permeation Parameters And Fracture Criteria, Sompong Prachumchon

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The permeation parameters of hydrogen gas in high density polyethylene (HDPE) system are sought by comparison with a diffusion model. The method of Green’s functions is used to obtain solutions for the diffusion model. Permeation parameters are found from transient experimented data during two processes; pressurization followed by depressurization. The mechanical compression of HDPE during the pressurization process resulted in lower diffusivity coefficient values and higher solubility values. The results show that the diffusivity coefficient value in the pressurization process is 37% of that during the depressurization process. At the start of the depressurization process, a short-duration fast flow rate …

Modular Joystick Design For Virtual Reality Surgical Skills Training, Michael Head

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A modular control interface and simulated virtual reality environment was designed and created in order to determine how the kinematic architecture of a control interface affects minimally invasive surgery. A user is able to selectively determine how many, the type, and location of degrees of freedom they require for the specific surgical simulation through the use of modular joints and constraint components. Furthermore, passive locking was designed and implemented through the use of inflated latex tubing around rotational degree of freedom joints. It is believed these features will have the ability to effectively simulate a variety of surgical simulations and …

Predicting Vehicle Dynamics For Roadside Safety Using Multibody Systems Simulations, Brett D. Schlueter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Accurate means for predicting vehicle dynamics is required in the design and testing of roadside safety hardware. Past research has used finite element (FE) modeling to this end, but multibody systems (MBS) modeling may provide a more efficient way to solve these problems. MBS modeling using Adams/Car was investigated by first compiling an introduction to the program, then performing basic vehicle dynamics simulations using a supplied model. Next, a model of a 2270 kg pickup was created and validated against physical test data involving impact with a speed bump. Finally, pickup trajectories in 4H:1V and 6H:1V V-ditches were predicted for …

Optimal Reduction Of Electrical Energy Consumption By Supply Air Ac Motors, Keyhan Rafiee

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The Nebraska Center for Energy Sciences Research (NCER) at the University of Nebraska-Lincoln (UNL) strives to be energy efficient through Green Energy. Of course, in meeting some of the requirements for different types of Leadership in Energy and Environmental Design (LEED) certification, certain minimum levels of energy efficiency practices must be met. One such level of energy efficiency, in particular, is reduction in the consumption of electrical energy in buildings. This thesis is a study of methods of reducing the consumption of electrical energy (measured in kW of electrical power) in the UNL Jorgensen Hall (JH) air handling unit 2 …

Automated Resonant Wireless Power Transfer To Remote Sensors From An Unmanned Aerial Vehicle, Brent Griffin

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Wireless magnetic resonant power transfer is an emerging technology that has many advantages over other wireless power transfer methods due to its safety, lack of interference, and efficiency at medium ranges. In this thesis, we develop a wire- less magnetic resonant power transfer system that enables unmanned aerial vehicles (UAVs) to provide power to, and recharge batteries of, wireless sensors and other electronics far removed from the electric grid. We address the difficulties of implementing and outfitting this system on a UAV with limited payload capabilities and develop a controller that maximizes the received power as the UAV moves into …

Design, Analysis And Testing Of Haptic Feedback System For Laparoscopic Graspers In In Vivo Surgical Robots, Nikhil Salvi

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Laparo-Endoscopic Single Site (LESS) Robotics Surgery is an advanced technology in the field of Minimally Invasive Surgery (MIS). The LESS surgical robots significantly improve the surgeon’s accuracy, dexterity and visualization, and reduce the invasiveness of surgical procedure results in faster recovery time and improved cosmetic results. In a standard robotic endosurgery, the palpation of tissues is performed by laparoscopic graspers located at the end effectors. The master-slave configuration in robotic surgery leads in remote access to the operation site. Therefore, surgeon’s ability to perceive valuable sensory information is severely diminished. Sensory information such as haptics, which is essential for safe …

Analysis Of Mechanically Milled Exchange Coupled Nanocomposite Permanent Magnets, Santanu Mukherjee

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Nanocomposite permanent magnets have recently evoked wide interest because of their interesting properties. They usually consist of a hard magnetic phase having superior coercivities and a soft magnetic phase having improved values of magnetization and when they are coupled together, we get a permanent magnet with enhanced values of both the parameters and thus can be put to a lot of applications. Also to make this possible we can take advantage of the principle of exchange interaction which has been discussed subsequently in detail.

Also the microstructure plays a major role in obtaining good magnetic properties and the microstructure is …

Identification Of A Maximum Guardrail Height For The Midwest Guardrail System Using Computer Simulation, Ramen D. Julin

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

W-beam guardrails are by far the most common restraint system used along both local and major roadways. Traditionally, these restraint systems have been full-scale crash tested with a rail height ranging between 27 in. and 32 in. However, the maximum rail height which allows for safe performance of guardrails, especially in impacts involving small vehicles, has never been identified.

The main concern associated with an increase of the rail height is that small vehicles, because of their low profile, may have a tendency to lift the rail and penetrate the barrier. The objective of this project was to determine the …

Material Handling System For Robotic Natural Orifice Surgery, Jeff Midday

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Natural Orifice Translumenal Endoscopic Surgery (NOTES) is a relatively new surgical approach which uses no external incisions, thereby improving cosmetic outcomes, decreasing overall recovery time and reducing the risk of external infection. In standard NOTES, flexible endoscopic tools have been used to carry out a variety of surgical procedures in the abdomen. As an alternative, miniature in vivo robots can be fully inserted into the peritoneal cavity and utilized to perform various surgical procedures. These in vivo robots eliminate tool triangulation issues, improve multi-tasking capabilities and greatly increase freedom and dexterity when compared to standard endoscopic and laparoscopic tools. One …

A Conductivity Testing System Coupled With A Tensile Testing Machine To Measure The Surface Properties Of Polymer Specimens, Nguyen T. Nguyen

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Polymers play an essential role in our everyday life due to their employment in a widespread range of applications. Polymers are used in industries such as space, biomedical, electronics, etc. in which their electrical and mechanical properties are major aspects which need to be investigated prior to implementation. When subjected to mechanical stimulations, polymers may exhibit changes in electrical conductivity which can vary locally within the specimens, especially in those of conducting polymers. In mechanical investigations a tensile testing machine is used to understand polymers’ strength, elasticity or other mechanical properties. In electrical analysis, using a four-point probe to examine …

The Integration Of Propane Flaming And Mechanical Cultivation For Effective Weed Control In Agriculture, Brian D. Neilson

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Flaming is a thermal weed control method that can kill weeds within or between crop rows using heat. Mechanical cultivation is another weed control method which undercuts weeds between crop rows to kill them. A combination flamer/cultivator implement was designed to take advantage of the good qualities of both flaming and cultivation to provide excellent organic weed control.

Flaming hoods were designed in the spring of 2010 and retrofitted on an existing row crop cultivator. The hoods were tested in corn and soybean field studies in the summer of 2010. Of the seven treatments tested, a treatment of flaming combined …

Improving Health Care Quality And Safety: The Development And Assessment Of Laparoscopic Surgery Instrumentation, Practices And Procedures, Bernadette Mccrory

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Adverse events due to medical errors are a leading cause of death in the United States exceeding the mortality rates of motor vehicle accidents, breast cancer and AIDS. Improvements can and should be made to reduce the rates of preventable surgical errors since they account for nearly half of all adverse events within hospitals. Although minimally invasive surgery has proven patient benefits such as reduced postoperative pain and hospital stay, its operative environment imposes substantial physical and cognitive strain on the surgeon increasing the risk of error. In order to mitigate errors and protect patients, a multidisciplinary approach was taken …

Effects Of Approach Techniques In Place Kicking: A 3d Analysis, Chase M. Pfeifer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Various studies aim to understand the fundamentals of kicking, primarily the instep kick commonly used by soccer players. Of those studies, most are limited to a 2D analysis using high-speed cameras for position tracking and electromyography to observe muscle activity. The few studies that investigate a 3D model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed. To the authors knowledge no study of this caliber has been performed on the kinematics and dynamics of place kicking in American football. This thesis uses a 12 camera high-speed motion tracking system to investigate …

Microstructure Selection Of Sm-Co-Al Alloys To Increase Magnetization, Brian Dick

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

An ever increasing demand for higher performing magnets drives the need for new and innovative methods to achieve this goal. Sm-Co rare earth permanent magnets have a unique eutectic microstructure that, through refinement, could become a two-phase magnet which would significantly increase their energy product. The eutectic structure of Sm₈Co₉₂ is comprised of αCo rods embedded within a Sm₂Co₁₇ matrix. If the rods are small enough to encourage exchange coupling and the matrix is smaller than the single domain limit, then an efficient two-phase magnet is created.

Refining the Co rods and matrix size …

Error Reduction And Effect Of Step Size In Adjustment Calculus For Cam Applications, Sai Siddhartha Nudurupati

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Any measurement, however carefully done, will never be free from errors. Similarly, machining of cams for automobiles is prone to contain errors. These errors are naturally a part and parcel of cam manufacturing. The nature of deviations of the manufactured cam profile from the theoretical cam determines its usability. Sometimes, allowable deviations in high speed cams may be in the order of 2540 µm. Larger deviations will disqualify the cams for applications.

Velocity and acceleration of the cam are estimated from the measured displacement of the cam follower during quality control implementation. This data helps in eliminating the unfit cams. …

Development And Recommendations For A Non-Proprietary, High-Tension, Cable End Terminal System, Ryan J. Terpsma

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Cable guardrail systems have been increasing in popularity in recent years due to several perceived benefits over the commonly used W-beam guardrail. A non-proprietary design was desired as an alternative to the many proprietary designs available. A non-proprietary, high-tension cable end terminal was necessary to accompany the non-proprietary, high-tension cable guardrail system under development.

The objective of this research project was to develop design recommendations for a non-proprietary, high-tension cable end terminal. An analysis of several cable guardrail end terminals was undertaken to identify any common features that may prove to be beneficial or detrimental to end terminal designs. Next, …