Mechanical Engineering Commons^™

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 Solar Powered Ceiling Fans, Florida Solar Energy Center

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.

Microscale Simulation Of Martensitic Microstructure Evolution, Valery I. Levitas, Alexander V. Idesman, Dean L. Preston

Valery I. Levitas

A new model for the evolution of multivariant martensitic microstructure in single crystals and polycrystals is developed. In contrast with Landau-Ginzburg models, which are limited in practice to nanoscale specimens, this new scale-free model is valid for length scales greater than 100 nm and without an upper bound. It is based on a thermodynamic potential in the volume fractions of the martensitic variants that exhibits an instability resulting in microstructure formation. Simulated microstructures in elastic single crystals and polycrystals under uniaxial loading are in qualitative agreement with those observed experimentally.

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 …

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 …

How A Mirage Is Formed, Christopher Roman

Christopher N. Roman

Article that appeared in Sail magazine (ISSN: 0036-2700).

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 2kW 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 an …

Energy Star Manufactured Homes: The Plant Certification Process, Florida Solar Energy Center, David 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 Reduction From 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 …

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

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 …

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

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 …

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, …

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 …

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 …

Synthesize Of Emulsion Polymer Latex For Sub-Grade Cbr Improvement In The Road Construction, Keba Moto, V. Julian, Syamsudin Syamsudin, T. A. Wiradi, S. R. Wijaya

Makara Journal of Technology

Synthesize of emulsion polymer latex for sub-grade CBR improvement in the road construction. Latex polymer for California Bearing Ratio (CBR) enhancement in sub-grade soil of road building has been prepared by emulsion polymerizations technique. The prepared polymer then characterize by Fourier Transform Infrared (FTIR). For application purpose, CBR test was done to the compacted polymer added-soil. The CBR test is done also for both soaked and unsoaked samples. It is found that our latex polymer is better then other imported latex polymer. For the latex polymer, which is design to have Temperatur glass (Tg) around 9.8-19.6o, indicating the formation of …

Effect Of Photoperiodicity On Co2 Fixation By Chlorella Vulgaris Buitenzorg In Bubble Column Photobioreactor For Food Supplement Production, Anondho Wijanarko, Dianursanti Dianursanti, Arief Budi Witarto, Roekmijati Widaningroem Soemantojo

Makara Journal of Technology

To reduce the level of CO2 content in air, effort on converting CO2 to useful products is required. One of the alternatives includes CO2 fixation to produce biomass using Chlorella vulgaris Buitenzorg. Chlorella vulgaris Buitenzorg is applied for production of food supplement. Chlorella vulgaris Buitenzorg is also easy to handle due to its superior adaptation. Currently, Chlorella vulgaris Buitenzorg has been analyzed by some experts for its cellular composition, its ability to produce high quality biomass and the content of essential nutrition. A series of experiments was conducted by culturing Chlorella vulgaris Buitenzorg using Beneck medium in bubbling column photobioreactor. …

Secondary Flow Experimental Study For Axial Compressor Cascade Strong Stagger With And Without Tip- Clearance: Static Pressure Distribution On Blade Surface, Syamsuri Syamsuri

Makara Journal of Technology

Secondary Flow Experimental Study for Axial Compressor Cascade Strong Stagger With and Without Tip- Clearance: Static Pressure Distribution on Blade Surface. The performance of blade cascade is influenced by the growth and boundary layer’s separation along blade surface and endwall (casing and hub). The secondary flow which happens near hub and casing compressors is three dimentional flow separation phenomenon comes from interaction blade boundary layer with casing and hub boundary layers in the compressor. The secondary flow causes secondary losses, blockage effect, and turning angle (deflection) distribution along blade span. The result of the research shows that the increase of …

Wavelenght-Dispersive X-Ray Flourescence Accuration, H. Widyatmoko

Makara Journal of Technology

Wavelenght–Dispersive X-Ray Flourescence Accuration. X-Fuorescence spectrometry is a method, which is increasingly applied in the geochemical analysis. X-Fuorescence spectrometry is classified under two categories – WDXRF (wavelenght – dispersive X-ray fluorescence spectrometer) and EDXRF (energy-dispersive X – ray fluorescence spectrometer). WDXRF can be configured as a sequential spectrometer , a simultaneous spectrometer or a hibrid instrument, which combines the advantages of the simultaneous and sequential spectrometers into one instrument. Each instrument is different in some characteristics, and each has applications for which it is specifically suited. In this investigation sequential spectrometer PW 1450 was used to analyze the major, minor …

Wire Bonding Challenges In Optoelectronics Packaging, Jianbiao Pan, Patrice Fraud

Industrial and Manufacturing Engineering

Wire bonding has been used in integrated circuit (IC) packaging for many years. However, there are many challenges in wire bonding for optoelectronics packaging. These challenges include bonding on sensitive devices, bonding over cavity, bonding over cantilevel leads and bonding temperature limitations. The optoelectronics package design brings another challenge, which requires wire bonding to have deep access capability. In this paper, the wire bonding technologies are reviewed and ball bonding and wedge bonding are compared. The variables that affect the wire bonding process are then discussed. Finally, the challenges of wire bonding in optoelectronics packaging are presented in detail.

Contribution Of Support Means To Stresses Developed In Sheet Metal Coils, Jonathan A. Wickert, Y.M. Lee

Jonathan A. Wickert

Sheet metal is often stored in large wound coils and processed through such manufacturing stages as cleaning, coating, and slitting in a finishing plant or thickness reduction in a rolling mill. During winding and unwinding operations, as well as during storage and transportation, a coil can be supported in a variety of methods. The coil can be formed on a relatively compliant fiber core, or it can be mounted with the core onto a drive shaft or a pair of core chucks. The stresses within the coil develop in response to the sheet metal's material properties, the process tension, and …

The Effect Of Heterogeneity On Plane Wave Propagation Through Layered Composites, X. Chen, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

When laminated composites are subjected to impact loading, the material response is critically determined by the interactions of multiple waves generated at the laminate interfaces. Due to the high complexity arising from the architectural details of composites, layered heterogeneous materials have been studied as the model system to understand the impact behavior of engineering composites. Previously, the present authors have developed an analytical solution to the problem of plate impact of layered systems; plate impact test is a standard boundary value problem used to study high velocity impact behavior both in the elastic and shock wave regimes. In this paper, …