Mechanical Engineering Commons^™

Me-Em Enewsbrief, March 2012, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Study On Fracture Behavior Of Aa5083–H111 Friction Stir Welded Joint, Mohammed El Sayed Allam

Theses

The fracture behavior of friction stir welded joints of aluminum alloy 5083-H111 was studied in this investigation. Different samples of stir welded joints at variable tool rotational speeds (1660 rpm, 850 rpm, and 675 rpm), different traveling speeds (24, 42, 55, 74, and 98 mm/min), and different tool pin shapes (cylindrical, tapered and threaded) were studied to investigate the effect of process parameters on the joint strength/load-bearing capacity. A series of tensile tests using an MTS machine, scanning electron microscope (SEM) analysis, and optical microscope analysis was conducted to study the effect of varying the rotational speed, traveling speed, and …

Advantages Of Gan Based Light-Emitting Diodes With A P-Ingan Hole Reservoir Layer, Taiping Lu, Shuti Li, Chao Liu, Kang Zhang, Yiqin Xu, Jinhui Tong, Lejuan Wu, Hailong Wang, Xiaodong Yang, Yian Yin, Guowei Xiao, Yugang Zhou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A p-type InGaN hole reservoir layer (HRL) was designed and incorporated in GaN based light-emitting diodes (LEDs) to enhance hole injection efficiency and alleviate efficiency droop. The fabricated LEDs with p-type HRL exhibited higher light output power, smaller emission energy shift and broadening as compared to its counterpart. Based on electrical and optical characteristics analysis and numerical simulation, these improvements are mainly attributed to the alleviated band bending in the last couple of quantum well and electron blocking layer, and thus better hole injection efficiency. Meanwhile, the efficiency droop can be effectively mitigated when the p-InGaN HRL was used.

Lunalight Project: Solar-Rechargeable Led Lantern And Cell Phone Charger, Sean C. Dawson, Michael E. Deagen, Francisco N. Dye, Brian S. Mircheff, Ryan O. Ramelb

Materials Engineering

Today, 1.6 billion people in the world do not have access to grid electricity. Villagers living off the grid in developing nations resort to kerosene lanterns to light their homes. The fumes from burning kerosene are toxic and lead to respiratory illnesses over time. Our sponsor, OneMillionLights, plans to help people to escape poverty by providing them with a clean source of light at night. Children that must work in the fields during the day can use a solar-rechargeable lantern at night to read or study, and street vendors can use the lanterns at night to improve their businesses.

The …

The Morphology Evolution And Voiding Of Solder Joints On Qfn Central Pads With A Ni/Au Finish, Julie Silk, Jianbiao Pan, Mike Powers

Industrial and Manufacturing Engineering

In this paper, we report on a comprehensive study regarding the morphology evolution and voiding of SnAgCu solder joints on the central pad of two different packages – QFN and an Agilent package called TOPS – on PCBs with a Ni/Au surface finish. Samples were isothermally aged at the equivalent of 0, 2, 7 and 14 years service life. Representative solder joints were cross-sectioned and analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) in order to investigate the evolution of the solder joint morphology as a function of Au content and isothermal aging. IMC thickness was …

Integration Of Massive Multiplayer Online Role-Playing Games Client-Server Architectures With Collaborative Multi-User Engineering Cax Tools, Joshua D. Winn

Theses and Dissertations

This research presents a new method for integrating client server architectures that are used for the development of Massive Online Role Playing Games (MMORPG) into multi-user engineering software tools. The new method creates a new architecture named CAx Connect by changing the client-pull-server communication pipeline to a server-push-client communication pipeline, effectively reducing the amount of bandwidth consumed and allowing these tools to utilize multiple server processors for complex calculations. This method was used on the new NX Connect multi-user CAx prototype developed at BYU. The new method provides a road map to further implement this architecture and its services into …

Achieving Very High Efficiency And Net Zero Energy In An Existing Home In A Hot-Humid Climate: Long-Term Utility And Monitoring Data, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

This study summarizes the first six months of detailed data collected about a single-family home that experienced a series of retrofits targeting reductions in energy use. The project was designed to develop data about how envelope modifications in heating, ventilation, and air conditioning and domestic hot water and renewable measures can result in considerable energy reductions and potentially net zero energy for an existing home. Using utility billing records and recent detailed monitoring data, this study was also able to chronicle the progress of energy reduction over a 22-year period.

Wmu Sunseeker Solarcar, Edmond Ing Huang Tan

The Hilltop Review

This picture was taken, at the racetrack the evening before the start of the North American Solar Challenge 2008 race in Plano, Texas. In this picture is the Sunseeker, Western Michigan University’s solar powered car that will race in the 2 week long, 2400miles long race from Plano, Texas to Calgary, Canada. Sunseeker was the only car in that race that feature a 2 electric motor drive system than the standard one electric motor drive system. Western Michigan University Sunseeker team brought back the sportsmanship award that year.

Microgas Turbine Engine Characteristics Using Biofuel, Edmond Ing Huang Tan, William W. Liou

The Hilltop Review

Aviation fuels commonly used today are extracted from the kerosene fraction of the crude oil that is distilled between the gasoline and the diesel. Crude oil is not renewable and the world oil reserve is generally believed to be on the decline. In 2006, 6.3% of the world's refinery production was used for aviation fuel (Nygren et. al., 2009). At an estimated rate of 3% increase of fuel demand per year, aviation use alone will consume the world fuel production by 2026. Therefore, there is a need for the aviation industry to reduce its dependence on fossil fuels and, perhaps, …

A New Approach For The Preparation Of Variable Valence Rare Earth Alloys From Nano Rare Earth Oxides At A Low Temperature In Molten Salt, Milin Zhang, Yongde Yan, Wei Han, Xing Li, Zhiyao Hou, Yang Tian, Ke Ye, Lihong Bao, Xiaodong Li, Zhijian Zhang

Faculty Publications

The solubility of RE₂O₃ (RE = Eu, Sm, and Yb) with variable valence in molten salts is extremely low. It is impossible to directly obtain variable valence metals or alloys from RE₂O₃ using electrolysis in molten salts. We describe a new approach for the preparation of variable valence rare earth alloys from nano rare earth oxide. The excellent dispersion of nano–Eu₂O₃ in LiCl–KCl melts was clearly observed using a luminescent feature of Eu³⁺ as a probe. The ratio of solubility of nano-Sm₂O₃/common Sm₂O_{3 …}

Transient Response Of Sloshing Fluid In A Three Dimensional Tank, Chih-Hua Wu, Bang-Fuh Chen

Journal of Marine Science and Technology–Taiwan

Sloshing waves in moving tanks have been studied numerically, theoretically and experimentally in the past several decades. Most reported studies have been for tanks excited by forcing motion in a limited number of directions and with fixed excitation frequencies throughout the forcing. In the present study, a time-independent finite difference method is used to simulate fluid sloshing in the three-dimensional tanks with arbitrary depths and the tanks are subject to a range of excitation frequencies with motions that exhibit multiple degrees of freedom. The developed numerical scheme is verified by rigorous benchmark tests, and the advantage and efficiency of the …

Semi-Analytical Solution For Radiation Of A Hollow Sphere With An Opening Hole In Finite Depth, Man-Sheng Dong, Guo-Ping Miao, Ju Fan, Ren-Chuan Zhu

Journal of Marine Science and Technology–Taiwan

An investigation is conducted on radiation of a submerged hollow sphere with an opening hole in finite water depth in this article. Based on the linear theory, the method of multipole expansions is used to obtain the fluid velocity potential in the form of double series of the associated Legendre functions with the unknown coefficients of an infinite set. In terms of the body surface boundary condition and the matching condition between the inner and outer flows at the hole, the complex matrix equations for the coefficients of the series are established. The infinite sets of matrix equations are solved …

Numerical Study On Significance Of Wind Action On 2-D Freak Waves With Different Parameters, Shiqiang Yan, Qingwei Ma

Journal of Marine Science and Technology–Taiwan

This paper presents a numerical study on how the significance of wind action differs when varying the wave parameters. The quasi arbitrary Lagrangian-Eulerian finite element method (QALE-FEM) is used for this purpose. An improved model for wind-excited pressure and wind-driven current, which is recently developed by the authors of this paper [27], is coupled with the QALE-FEM. Many cases involving freak waves with different focusing time/point and frequency ranges under the action of winds are investigated. The results show that the significance of wind actions on freak waves strongly depends on the focusing time, the focusing point and the frequency …

The Influence Of Nozzle Spacing And Diameter On The Acoustic Emissions Of Closely Spaced Supersonic Jet Arrays, Ian S. Coltrin

Theses and Dissertations

The acoustic emissions from supersonic jets represent an area of significant research needs; not only in the field of aero-acoustics, but in industry as well where high pressure let down processes have been known to cause acoustically induced vibrations. A common method to reduce the acoustic emissions of such processes involves dividing the single larger supersonic flow into several smaller ones. Though this is common practice, there is not yet a current model which describes the reduction of acoustic emissions from an array of smaller supersonic jets. Current research which studies supersonic jet arrays are mainly focused on the effects …

The Design And Fabrication Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Robert Gonsalves

Master's Theses

A microfluidic reactor for synthesizing cadmium selenide (CdSe) quantum dots (QDs) was synthesized out of a silicon wafer and Pyrex glass. Microfabrication techniques were used to etch channels into the silicon wafer. Holes were wet-drilled into the Pyrex glass using a diamond-tip drill bit. The Pyrex wafer was anodically bonded to the etched silicon wafer to enclose the microfluidic reactor. Conditions for anodic bonding were created by exposing the stacked substrates to 300V at ~350oC under 5.46N of force. A syringe containing a room temperature CdSe solution was interfaced to the microfluidic reactor by using Poly (dimethylsiloxane) (PDMS) as an …

Evaluating Superconducting Ybco Film Properties Using Xray Photoelectron Spectroscopy, Paul N. Barnes, Justin C. Tolliver, Timothy J. Haugan, Sharmila M. Mukhopadhyay, John T. Grant

Mechanical and Materials Engineering Faculty Publications

Initial results have been recently reported that suggest a potential correlation exists between the full-width-halfmaximum (FWHM) of the Y(3d) peak obtained by x-ray photoelectron spectroscopy (XPS) and the critical current density a YBa₂Cu₃O₇-x film can carry. In particular, the Y(3d_5/2) demonstrated a stronger correlation. Transport currents were determined by the 4-point contact method using the 1μV/cm criterion. An apparent correlation was also suggested between the Y(3d) FWHM and ac loss data points were acquired to further test the usefulness of the correlations. Samples were created by pulsed laser deposition of YBa_{2 …}

Inertia Gap Between Md Simulations And Afm Experiments In Study Of Atomic Friction, Yalin Dong, Qunyang Li, Robert W. Carpick, Ashlie Martini

Mechanical Engineering Faculty Research

Both atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulation are carried out to investigate atomic stick-slip friction by sliding a Pt tip on an Au substrate. Efforts are taken to match the conditions for AFM experiment and MD simulation as closely as possible. The results show that AFM and MD provide consistent energetic parameters, which suggests that MD simulations can be reliably used to interpret energetic aspects of the interfaces. However, orders of magnitude differences in attempt frequencies are found, which indicates another challenge between the MD simulations and AFM experiments, i.e., the inertia gap.

Effects Of Mismatched Electrodes On An At-Cut Quartz Resonator, Huijing He, Jinxi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We study thickness-shear and thickness-twist free vibrations of a finite AT-cut quartz resonator with mismatched electrodes. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56. An analytical solution is obtained using Fourier series from which the resonant frequencies, mode shapes, and vibration confinement resulting from the electrode inertia are calculated and examined.

Study Of Turbulence-Radiation Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín, A. M. Feldick, M. F. Modest, D. A. Levin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct numerical simulations are conducted to investigate the effect of turbulence-radiation interaction in hypersonic turbulent boundary layers, representative of the Orion crew exploration vehicle at the peak heating condition during reentry. Both the effects of emission and absorption are considered by solving the radiative transfer equation using the tangent slab approximation and a spectral model with line-by-line accuracy. Nondimensional governing parameters to measure the significance of turbulence-radiation interaction are proposed, and the direct numerical simulation fields with and without radiation coupling are used to assess turbulence-radiation interaction. Is it found that the fluid medium within the boundary layer is optically …

The Mechanical Testing Of Single Nanofiber, Pratik Manohar Dahule

Theses

Polymer nanofibers exhibit properties that make them a favorable material for the development of tissue engineering scaffolds, filtration devices, sensors, and high strength lightweight materials. Perfectly aligned PLLA Nanofibers were fabricated by an electrospinning technique under optimum conditions and the diameter of the electrospun fibers can easily be tailored by adjusting the concentration of the polymer solution. To align the nanofibers, special arrangement was made in terms of two aluminum plates. Good alignment of polymer nanofibers on specimen was confirmed by SEM observation. The effect of different electro-spinning parameters on maximum fiber length, average fiber diameter, diameter uniformity, and fiber …