Mechanical Engineering Commons^™

An Algorithm For Locating Fundamental Frequency (F0) Markers In Speech, Princy Dikshit

Electrical & Computer Engineering Theses & Dissertations

Speech has been the principal form of human communication since it began to evolve at least one hundred thousand years ago. Speech is produced by vibrations of the vocal cords. The rate of vibration of the cords is called fundamental frequency (F0) or pitch. The objective of this thesis is to locate pitch period cycles on a cycle-by-cycle basis. The complexity in identifying pitch cycles stems from the highly irregular nature of human speech. Dynamic programming is used to combine two sources of information for pitch period marking. One source of information is the "local" information corresponding to the location …

Modal Analysis And Validation Of A Gasoline Fuel Injector Using Ansys And Laser Vibrometer, Ravi Kiran Kothamasa

Mechanical & Aerospace Engineering Theses & Dissertations

In the present day market it has been demonstrated that quality and speed make a product successful. An automobile has hundreds of components, which work in synchronization to make the automobile run smoothly. The fuel injector is one of the key components of an automobile. The primary functions of a fuel injector are: to deliver measured quantity of fuel to the engine, to atomize fuel for efficient combustion process, to deliver measured or atomized quantity of fuel to the desired target within manifold/head, and to shut off the fuel supply when no fuel is required. When this fuel injector is …

Effects Of Track Irregularities On Dynamic Responses Of A Moving Maglev Train, Aravind M. Hanasoge

Mechanical & Aerospace Engineering Theses & Dissertations

The Maglev project at Old Dominion University is a collaboration between Old Dominion, American Maglev Technology (AMT), Lockheed Martin, other industry participants and the federal and state governments. This project began at the Norfolk campus in 2002. Under this project, researchers are aiming for a demonstrable engineering prototype that will operate smoothly at speeds of 40 - 45 miles per hour along the 3400 feet long track.

During testing, the vehicle is found to vibrate violently when operated on the ground. Furthermore, the vehicle failed to levitate when operated on the elevated track. As part of the investigation to determine …

Effects Of Initial Seated Position On Whiplash In Low Speed Rear-End Impacts Comparison And Study Using The Tno Rear Impact Dummy (Trid) Model, Manjunath P. Venkataramana

Mechanical & Aerospace Engineering Theses & Dissertations

Despite numerous investigations devoted to its scrutiny, injury causing mechanism associated with rear-end impact collision producing injury such as Whiplash Associated Disorder (WAD) has remained a mystery. Several criteria have been proposed to predict the injury causing mechanism, but none have been universally accepted. The challenge lies in determining a set of testing procedures representative of real-world collisions, wherein the results obtained are not only the same as human testing, but remain consistent with various subjects and impact conditions. It is hypothesized that one of the most important considerations is the effect of initial seated position (ISP).

This thesis can …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic: Quarterly Progress Report (July 1 – Sept. 30, 2004), Yingtao Jiang, Bingmei Fu

Transmutation Sciences Materials (TRP)

Dr. Jiang Ma and Mr. Xiaolong Wu worked in LANL between July 1 and Sept. 15 to conduct the experiment. Test of the corrosion of different materials in LBE was performed. The influence of the process of gas introduction to the LBE was studied. Data analysis work was performed based on accumulated data. In the same time, progress has been made in the simulation for transport in oxygen mixing, and one paper was presented in a conference. Another paper was composed and submitted to IEEE International Symposium of Circuits and Systems for the track Chemical Sensors. Preparation of a paper …

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2004 Through September 30, 2004, Anthony Hechanova

Publications (NSTD)

UNLV hosted a meeting on NHI Materials and Heat Exchanger Design on Monday, May 17. Paul Pickard (Sandia National Lab) and Bill Corwin (Oak Ridge National Lab) facilitated the meeting. The purpose of the meeting was to summarize the hydrogen materials and heat exchanger requirements and priorities for UNLV staff and their collaborators to support the research proposal solicitation for the UNLV Research Foundation HTHX program. Attendance was heavier than anticipated and required a change of venue to accommodate the crowd of over 30.

Solvent And Method For Extraction Of Triglyceride Rich Oil, Shubhender Kapila, Paul Ki-Souk Nam, V. J. Flanigan

Chemistry Faculty Research & Creative Works

The present invention relates to a solvent for use in extracting oil from an oil bearing material, such as soybeans, with the solvent resulting in the selective extraction of a triglyceride rich oil, which contains 95% or greater triglycerides and non-polar constituents, with the solvent comprised of a hydrocarbon, preferably hexane, and a fluorocarbon, so that the solvent has a viscosity less than 2.6 centipoise and a polarity of less than 0.1. The present invention also relates to a method of using the solvent to extract the triglyceride rich oil, with the method including preferably extracting the oil at a …

The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan

Theses and Dissertations

In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …

A Review Of Setup Practices And Procedures For Creating Ieee 802.11 Wireless Community Networks, Jae M. Theobald

Theses and Dissertations

IEEE 802.11 wireless networking equipment has made it possible to bridge the last mile for new broadband internet service providers. Inexpensive wireless networking equipment and high gain antennas enable high speed internet delivery at a fraction of the cost of installing or upgrading land lines for cable or DSL services. Based on this research, a guide of general practices and procedures is proposed for designing, installing, and maintaining a reliable wireless community area network. Included tests have provided performance results for several types of wireless antennas (including wire grid parabolic dishes, Yagi and Vagi styles, and echo backfire), wireless bridges, …

Numerical Simulations In Electro-Osmotic Flow, Joseph S. Tenny

Theses and Dissertations

The developing flow field in a parallel plate microchannel, induced by wall motion, has been modeled numerically. This type of flow simulates the physical driving mechanism that exists in electro-osmotically generated flow with large channel diameter-to-Debye length ratios (Z). The physics of the flow field were compared between the moving wall model (MWM) and electro-osmotic flow (EOF) at Reynolds numbers of 1 and 1800, and Z > 2500. Also, Z-values between 50 and 500 were studied to investigate the accuracy of the MWM. Results show that for Z-values greater than 100 the MWM shows good agreement with EOF.

The dynamics of …

An Open Architecture For Versatile Machine And Actuator Control, Michael Scott Baxter

Theses and Dissertations

Automatic control technology increases usability, reliability and productivity in manufacturing, transportation, and climate control. There are many additional areas of modern life that could benefit through automatic control; however, current automation components are too expensive or aren't sufficiently flexible. For example, the cost of current commercial motion control components precludes their use in an average home. This thesis describes an automatic control methodology that is low cost and is flexible enough for a wide variety of control applications. Typical applications could include:

- Home lighting, security and appliances

- Commercial building heating, ventilation and air conditioning

- Industrial machine tool …

Performance And Applications Of Gossamer Wind (Tm) Solar Powered Ceiling Fans, Florida Solar Energy Center, M. Lubliner

FSEC Energy Research Center®

Ceiling fans provide a cooling breeze, reduce temperature stratification and improve thermal comfort. Ceiling fans save energy in homes by improving thermal comfort, which results in changes to the thermostat set-point or reduced use of air conditioning.

Initial Experiments In The Cooperative Control Of Unmanned Air Vehicles, Derek R. Nelson, Timothy W. Mclain, Reed S. Christiansen, Randal W. Beard, David Johansen

Faculty Publications

This paper addresses cooperative control for a team of unmanned air vehicles (UAVs). Specifically, a team of three small UAVs is controlled to perform a cooperative timing mission. Starting at loiter locations distributed around the periphery of a 2 km square battle area, the UAVs cooperatively plan paths to arrive at a target at the center of the battle area in sequence at 10 sec intervals. Cooperative path planning is performed using the methodology of coordination variables and coordination functions. Coordination and waypoint path planning are centralized on a ground station computer. Experiments have been performed using BYU’s fleet of …

Electrostatic Radio Frequency (Rf) Microelectromechanical Systems (Mems) Switches With Metal Alloy Electric Contacts, Ronald A. Coutu Jr.

Theses and Dissertations

RF MEMS switches are paramount in importance for improving current and enabling future USAF RF systems. Electrostatic micro-switches are ideal for RF applications because of their superior performance and low power consumption. The primary failure mechanisms for micro-switches with gold contacts are becoming stuck closed and increased contact resistance with increasing switch cycles. This dissertation reports on the design, fabrication, and testing of micro-switches with sputtered bi-metallic (i.e., gold (Au)-on-Au-(6.3at%)platinum (Pt)), binary alloy (i.e., Au-(3.7at%)palladium (Pd) and Au-(6.3at%)Pt), and ternary alloy (i.e., Au-(5at%)Pt-(0.5at%)copper (Cu)) contact metals. Performance was evaluated, in-part, using measured contact resistance and lifetime results. The micro-switches with …

A Tightly-Coupled Ins/Gps Integration Using A Mems Imu, Jonathan M. Neu

Theses and Dissertations

Micro-Electro-Mechanical Systems (MEMS) technology holds great promise for future navigation systems because of the reduced size and cost of MEMS inertial sensors relative to conventional devices. Current MEMS devices are much less accurate than standard inertial sensors, but they can still be useful. In this thesis, data was recorded from an inexpensive MEMS inertial measurement unit and integrated with GPS measurements using a tightly-coupled Kalman filter. The overall goal of this research is to investigate the usefulness of MEMS sensors for a small, real-time, low-cost INS/GPS integration. A golf cart was used to collect dynamic data, along with a commercial …

Membrane Laminar Wet Electrostatic Precipitator, Hajrudin Pasic, M. Khairul Alam, David J. Bayless

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A laminar flow, wet electrostatic precipitator (ESP) with planar collecting electrodes preferably made of membranes, such as a woven silica fiber. The collecting electrodes are spaced close to planar discharge electrodes to promote laminar flow (Re<2300). Charging electrodes are positioned upstream of the wet ESP to charge the particulate entering the wet ESP to promote collection. The wet ESP is preferably downstream from a conventional turbulent dry ESP for collecting a substantial portion of the larger particulate in the gas stream prior to the gas stream entering the wet ESP.

Photovoltaics: Disaster And Energy Security Applications, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

The modernization of our lives with the use of electronic devices has contributed to a steadily increasing dependence on electric power. The degree of importance of electricity is temporarily highlighted with any type of power outage, whether caused by an accident, a natural disaster or a terrorist attack. A disaster can leave many people without adequate medical services, potable water, electrical service and communications.

There is a value in applying photovoltaics (solar electric) to create disaster-resistant buildings and communities, which is to reduce losses and improve quality of life. Photovoltaics provide a viable source of electric power for energy security …

Geographic Variation In Potential Of Rooftop Residential Photovoltaic Electric Power Production In The United States, Florida Solar Energy Center, Matthew Lombardi

FSEC Energy Research Center®

This paper describes a geographic evaluation of Zero Energy Home (ZEH) potential, specifically an assessment of residential roof-top solar electric photovoltaic (PV) performance around the United States and how energy produced would match up with very-efficient and super-efficient home designs. We performed annual simulations for 236 TMY2 data locations throughout the United States on two highly-efficient one-story 3-bedroom homes with a generic grid-tied solar electric 2 kW PV system. These annual simulations show how potential annual solar electric power generation (kWh) and potential energy savings from PV power vary geographically around the U.S. giving the user in a specific region …

Energy Star Manufactured Homes: The Plant Certification Process, Florida Solar Energy Center, Dave Chasar

FSEC Energy Research Center®

In an on-going collaboration over the last ten years, researchers have worked with the manufactured housing industry offering building science advice and conducting diagnostic testing (Chandra et al 2002). This partnership resulted in the first two HUD code ENERGY STAR homes in 1997 and the development of standardized, in-plant Duct Blaster testing in 2001. One manufacturer is currently testing duct leakage on every home in 12 factories, representing over 8,000 homes per year.

In 2001, the U.S. Environmental Protection Agency (EPA) introduced the ENERGY STAR label for manufactured homes. Guidelines for this program focus on certification of the HUD-code plant …

Measured Energy And Peak Demand Reductionfrom High Efficiency Air Conditioner Replacement, Florida Solar Energy Center, John Masiello

FSEC Energy Research Center®

A utility load research project has monitored over 167 single-family residences in Central Florida collecting baseline 15-minute data on air conditioner (AC) power consumption, interior air temperatures and appliance loads over a two year period. Within the project we evaluated the impact of replacing older existing air conditioners with modern high efficiency equipment.

Modeling Concrete Masonry Walls Subjected To Explosive Loads, Christopher D. Eamon, James T. Baylot, James L. O'Daniel

Civil and Environmental Engineering Faculty Research Publications

Concrete masonry unit walls subjected to blast pressure were analyzed with the finite element method, with the goal of developing a computationally-efficient and accurate model. Wall behavior can be grouped into three modes of failure, which correspond to three ranges of blast pressures. Computational results were compared to high-speed video images and debris velocities obtained from experimental data. A parametric analysis was conducted to determine the sensitivity of computed results to critical modeling values. It was found that the model has the ability to replicate experimental results with good agreement. However, it was also found that, without knowledge of actual …

Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu

Journal of Marine Science and Technology–Taiwan

According to the Stokes micro-continuum theory, the effects of couple stresses upon the steady-state performance of wide parabolicshaped slider bearings are presented in this paper. To account for the couple stress effects arising from a Newtonian lubricant blended with various additives, the modified non-Newtonian Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. Comparing with the traditional Newtonianlubricant case, the effects of couple stresses characterized by the couple stress parameter signify an improvement in the steady-state performance. Increasing values of the couple stress parameter increases the bearing load-carrying capacity and reduces the required volume flow …

Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang

Journal of Marine Science and Technology–Taiwan

In the present study, the atomization of a coaxial injector in the liquid/gas engine combustor was numerically investigated. Based on the wave instability analysis of the interface between liquid and gas, an atomization model for the high-speed liquid jets was established by coupling with the jet flow solutions. First, the wave instability was analyzed to predict the growth rates along the liquid jet surface by numerically solving the wave dispersion equation, while the governing equations of the liquid flow were solved for the formation of the liquid jet core and the variation of the liquid flow structure. Then, these two …

Preliminary Evaluation Of Performance Enhanced Relocatable Classrooms In Three Climates, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

A research project has monitored a specifically modified energy efficient portable classroom compared with a standard unit, in side-by-side installations in three states (NY, NC and FL). Energy performance data is summarized in this paper.

Bass Code Development, Scott Sawyer

Mechanical Engineering Faculty Research

The BASS computational aeroacoustic code solves the fully nonlinear Euler equations in the time domain in two-dimensions. The acoustic response of the stator is determined simultaneously for the first three harmonics of the convected vortical gust of the rotor. The spatial mode generation, propagation and decay characteristics are predicted by assuming the acoustic field away from the stator can be represented as a uniform flow with small harmonic perturbations superimposed. The computed field is then decomposed using a joint temporal-spatial transform to determine the wave amplitudes as a function of rotor harmonic and spatial mode order. This report details the …

Development Of Image Processing Tools For Analysis Of Laser Deposition Experiments, Todd E. Sparks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microscopical metallography is a well established field with a long history of techniques for measuring features. Modern computational power allows much more rigorous investigation than simple area fractions and intercept measurements. This paper details the development of image processing tools using GNU Octave, a free, open source numerical computation package. Proposed in the paper is a method for characterizing features within a digital microscope image.

Experimental Investigation Of Laser Metal Deposition Of Functionally Graded Copper And Steel, Vinay Kadekar, Sashikanth Prakash, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition is an emerging technology for producing fully dense metallic parts. This process shows a promising future for the deposition of functionally graded steel - copper alloys. Good thermal conductivity of copper and a high wear resistance of steel can be achieved in dies and cores. However, to accomplish this, there are many issues to be resolved, such as the formation of an undesirable phase, solidification cracking, porosity at the interface and difference in thermal coefficient of expansion between steel and copper. The influences of process variables, such as laser power, laser scan speed, composition, powder flow rate, …

Numerical And Experimental Analysis Of The Powder Flow Streams In The Laser Aided Material Deposition Process, Yogesh D. Thakar, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Axial powder stream concentration between the nozzle end and the deposition point is an important process parameter in the laser aided material deposition process. The powder concentration is greatly influenced by the nozzle geometry in use. This paper describes the numerical and experimental analysis of this important parameter in relation to the coaxial nozzle. The experiments are performed with the different nozzle geometries to generate various flow patterns of the gravity fed powder in a cold stream. The results of the experimental analysis are compared with the numerical simulation and found justified. These results are used in concluding the significance …

Modeling Of The Metal Powder Flow With Carrier Gas In Coaxial Nozzle For Direct Laser Deposition Process, Heng Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In direct laser deposition process, metal powder is directly fed with carrier gas through the coaxial nozzle into the melt pool created by the laser to form the solid parts. Many operational parameters of the process depend on the characteristic of the powder stream structure below the exit of the coaxial nozzle. In this paper, a computational approach is developed for the simulation of the gas-particle flow in the coaxial nozzle. By taking into account the nozzle geometry and operating parameters, such as width and inclination angle of powder passage and carrier gas velocity, the developed computational code allows the …

Study Of Ceramic Slurries For Investment Casting With Ice Patterns, Qingbin Liu, Ming-Chuan Leu, Harish Jose, Von Richards

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice patterns generated by rapid freeze prototyping or a molding process can be used to make ceramic investment molds for metal castings. Due to the use of ice, the ceramic slurries must be poured around the pattern and cured at sub-freezing temperatures. Success of this process depends greatly on the mold strength after the gelation of the slurries. This paper describes the experimental results of the mold strength after the gelation of the slurries under different compositions. The parameters considered include mixing time, alumino-silicate vs. fused silica ratio, volume of binder, and volume of catalyst. The strength of the gelled …