Engineering Commons^™

Promoting Electrocatalytic Activity Of A Composite Sofc Cathode La0.8Sr0.2Mno3+Δ/Ce0.8Gd0.2O2-Δ With Molten Carbonates, Yunhui Gong, Xue Li, Lingling Zhang, Whitney Tharp, Changyong Qin, Kevin Huang

Faculty Publications

The effect of molten carbonates (MCs) on polarization resistance (R_P), a direct measure of oxygen reduction reaction (ORR) activity, of a composite La_0.8Sr_0.2MnO_3+δ/Ce_0.8Gd_0.2O_2-δ (LSM/GDC) solid oxide fuel cell (SOFC) cathode has been systematically investigated in this study over a temperature range of 550–650°C and partial pressure of oxygen (pO₂) span of 10⁻³ ∼ 1 atm. It is shown that the LSM/GDC cathode, either in the pristine or MC-modified states, can be generally modeled by two consecutive parallel circuits consisting of a resistance and a …

Applying Best Practices To Florida Local Government Retrofit Programs, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

In some communities, local government and non-profit entities have funds to purchase and renovate distressed, foreclosed homes for resale in the affordable housing market. Numerous opportunities to improve whole house energy efficiency are inherent in these comprehensive renovations. BA-PIRC worked together in a multiyear field study making recommendations in individual homes, meanwhile compiling improvement costs, projected energy savings, practical challenges, and labor force factors surrounding common energy-related renovation measures. The field study, Phase 1 of this research, resulted in a set of best practices appropriate to the current labor pool and market conditions in central Florida to achieve projected annual …

College Of Engineering Senior Design Competition Fall 2013, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …

Nd-Fe-B Nanoparticles Through Surfactant Assisted Mechanical Milling And Alloy Design, Jordann M. Bornhoft

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

Surfactant-assisted mechanical milling has been used to produce discrete nanoparticles of both Nd-Fe-B and Sm-Co amenable for bottom-up production of nanostructured or nanocomposite permanent magnets. However, in Nd-Fe-B the comminution of the material proceeds by transgranular fracture, which influences both the morphology of the nanoparticles and the magnetic properties. This paper utilizes alloy design to alter the fracture behavior from transgranular fracture to intergranular fracture. Nd-rich Nd₂Fe₁₄B alloys were produced by melt spinning in an overquenched state. The melt spun ribbons were annealed at 700°C and 800°C to ensure complete crystallization and to form different grain …

Fabrication And In Vivo Thrombogenecity Testing Of Nitric Oxide Generating Artificial Lungs, Kagya Amoako, Patrick Montoya, Terry C. Major, Ahmed B. Suhaib, Hitesh Handa, David O. Brant, Mark E. Meyerhoff, Robert H. Bartlett, Keith E. Cook

Mechanical and Industrial Engineering Faculty Publications

Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1–2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N = 5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for …

Loading Path Determination For Tube Hydroforming Process Of Automotive Component Using Apdl, E. Masoumi Khalil Abad, Amir Ghazanfari, R. Hashemi

Faculty Publications, Mechanical Engineering

In this study, an extended stress-based forming limit diagram (FLD) for prediction of necking based on the Marciniak and Kucznski (M-K) model is represented and applied in tube hydroforming. The bulge forming of a straight tube is simulated by finite element method and verified with published experimental data. This adaptive simulation technique is based on the ability to detect the onset and growth of defects (e.g., bursting and wrinkling) and to promptly readjust the loading paths. Thus, a suitable load path is determined by applying Adaptive Simulation Method in ANSYS Parametric Design Language (APDL).

Physics Trick - Balanced Can, Said Shakerin

All Faculty Articles - School of Engineering and Computer Science

The ordinary 12-oz beverage cans in the figures below are not held up with any props or glue. The bottom of such cans is stepped at its circumference for better stacking. When this kind of can is tilted, as shown in Fig. 1, the outside corners of the step touch the surface beneath, providing an effective contact about 1 cm wide. Because the contact is relatively wide and the geometry is symmetrical, it is easy to balance an empty can by simply adding an appropriate amount of water so that the overall center of mass is located directly above the …

Wind Tunnel Testing And Numerical Simulation On Aerodynamic Performance Of A Three Bladed Savonius Wind Turbine, Khandakar Niaz Morshed, Mosfequr Rahman, Gustavo Molina, Mahbub Ahmed

Department of Mechanical Engineering Faculty Publications

The purpose of this research work is to investigate experimentally and computationally the feasibility of improving the performance of the vertical-axis Savonius wind turbine. The authors first performed a series of wind tunnel investigations on semi-cylindrical three-bladed Savonius rotor scale models with different overlap ratios and without overlap. These experiments were conducted in front of a low-speed subsonic wind tunnel at different Reynolds numbers. Pressures around the concave and convex surfaces of each blade, as well as the static torque for the rotor models, were measured. Using these experimental data, the authors calculated aerodynamic characteristics such as drag coefficients, static …

Kinematic Synthesis Of Planar, Shape-Changing, Rigid Body Mechanisms For Design Profiles With Significant Differences In Arc Length, Shamsul A. Shamsudin, Andrew P. Murray, David H. Myszka, James P. Schmiedeler

Mechanical and Aerospace Engineering Faculty Publications

This paper presents a kinematic procedure to synthesize planar mechanisms capable of approximating a shape change defined by a general set of curves. These “morphing curves,” referred to as design profiles, differ from each other by a combination of displacement in the plane, shape variation, and notable differences in arc length. Where previous rigid-body shape-change work focused on mechanisms composed of rigid links and revolute joints to approximate curves of roughly equal arc length, this work introduces prismatic joints into the mechanisms in order to produce the different desired arc lengths. A method is presented to iteratively search along the …

Me-Em Enewsbrief, December 2013, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.

Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason Gerald Vogeler

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Polycarbonate (PC) is a tough, transparent engineering thermoplastic. Its impact strength and ability undergo large plastic deformations without shatter make PC an ideal protective material for impact-resilient eyewear, aircraft windows and transparent armor. A good understanding of the response of this material to large deformations at high strain rates is critical for its utilization in these applications. To this end, a striker-less Kolsky bar device is employed in this work for the needed material characterization. The apparatus allow impulsive torsion and/or compression loadings with pulse durations sufficiently long for the plastic flow behavior to develop fully. Three new testing techniques …

Ultrasonic Propagation And Scattering In Pearlitic Steel, Hualong Du

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Diffuse ultrasonic backscatter measurements have been especially useful for extracting microstructural information and for improving flaw detection in materials. In this dissertation, this approach is applied to inspection of railroad wheels. To improve the wear resistance, the tread surfaces of railroad wheels are usually quenched with water to increase the hardness. The pearlite phase of iron, characterized by alternating ferrite and cementite phases, is created by the quenching and the lamellar spacing within grains increases progressively from the quenched tread surface to deeper locations due to the non-uniform cooling rate. The quench depth is an important parameter governing the wheel …

Structural & Magnetic Characterization Study Of Hfco7 Alloy With Substitutions Of Si, Ti, Fe, Mn & B, Jacob A. Lewis

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

Magnetic materials are a critical component of the modern technological society. The market of high-energy product hard magnets is dominated by the rare-earth element containing neodymium-iron-boron (NdFeB) magnets. As a result of worldwide demand coupled with trade restrictions on rare-earth minerals, new magnet compositions are explored to reduce pressure on the already strained market. The hafnium-cobalt alloy system has shown promise as a candidate for filling the gap in saturation magnetization between rare-earth containing alloys and those made with abundant elements. This study explores the magnetic effects of silicon, titanium, iron, manganese and boron substitutions in the hafnium-cobalt-7 (1:7 atomic …

Experimental Study On The Effect Of Air Flow On Soap Bubble Formation, John M. Davidson

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

Soap bubbles are a common interfacial fluid dynamics phenomenon having applications such as buoyant hollow spherical fillers and flow visualization of large scale airflows. In contrast to the dynamics of liquid drops in gas and gas bubbles in liquid, the dynamics of soap bubbles has not been well documented, possibly because soap bubbles have gas-liquid-gas interfaces. Having the thin-liquid-film interface seems to alter the characteristics of the bubble/drop creation process. Thus, the main objective of this study is to experimentally examine how airflow develops and interacts with the soap liquid film as the film stretches and finally collapses to pinch-off. …

Improving Global Impact: How The Integration Of Remotely Reporting Sensors In Water Projects May Demonstrate And Enhance Positive Change, Evan A. Thomas

Mechanical and Materials Engineering Faculty Publications and Presentations

This article argues that improved feedback on the actual impact of development programs may ensure the success of poverty reduction interventions such as water filters, water pumps, latrines, and cookstoves.

Effects Of Time Varying Background Noise Conditions On Human Perception And Performance, Andrew H. Hathaway

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

This thesis was designed to study the effects of changing noise conditions on human perception and performance. In two phases, participants were exposed to a number of noise conditions and their performance on an arithmetic task involving short-term memory was monitored and their subjective perception of noise conditions was collected via questionnaires.

In the first phase, participants were tested while being subjected to RC-29(H) and RC-47(RV) conditions created by broadband noise fluctuating on different time intervals, resembling the changing noise conditions potentially found in modern HVAC systems. These intervals varied from two minutes to ten minutes. Results show a significant …

Near-Infrared Surface-Enhanced Fluorescence Using Silver Nanoparticles In Solution, Michael D. Furtaw

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

Fluorescence spectroscopy is a widely used detection technology in many research and clinical assays. Further improvement to assay sensitivity may enable earlier diagnosis of disease, novel biomarker discovery, and ultimately, improved outcomes of clinical care along with reduction in costs. Near-infrared, surface-enhanced fluorescence (NIR-SEF) is a promising approach to improve assay sensitivity via simultaneous increase in signal with a reduction in background. This dissertation describes research conducted with the overall goal to determine the extent to which fluorescence in solution may be enhanced by altering specific variables involved in the formation of plasmonactive nanostructures of dye-labeled protein and silver nanoparticles …

Liquid Phase Stability Under An Extreme Temperature Gradient, Zhi Liang, Kiran Sasikumar, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using Nonequilibrium Molecular Dynamics Simulations, We Subject Bulk Liquid to a Very High-Temperature Gradient and Observe a Stable Liquid Phase with a Local Temperature Well above the Boiling Point. Also, under This High-Temperature Gradient, the Vapor Phase Exhibits Condensation into a Liquid at a Temperature Higher Than the Saturation Temperature, Indicating that the Observed Liquid Stability is Not Caused by Nucleation Barrier Kinetics. We Show that, Assuming Local Thermal Equilibrium, the Phase Change Can Be Understood from the Thermodynamic Analysis. the Observed Elevation of the Boiling Point is Associated with the Interplay between the "Bulk" Driving Force for the Phase …

Investigation Of Thermal Cycle And Hardness Distribution In The Laser Cladding Of Aisi H13 Tool Steel Produced By A High Power Direct Diode Laser, Parisa Farahmand, Prabu Balu, Fanrong Kong, Radovan Kovacevic

Mechanical Engineering Research

Laser cladding (LC) of tool steel has significant application in rapid tooling, and surface coating for worn-out components in different industries. During the LC process, several phase transformations influence the microstructural and mechanical properties of the deposited layer. In order to successfully implement the LC process, it is essential to understand the relationship between the thermal cycle (heating and cooling), phase transformations, and the output quantities of the deposited layer. In this study a direct diode laser with a power of up to 8 kW was used to deposit AISI H13 tool steel on mild steel grade A36 substrate to …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering News (2013-2023)

• Accepting Applications for National Science Foundation: Research Experience for Undergraduates

Ergonomichandle And Articulating Laparoscopictool, M. Susan Hallbeck, Dmitry Oleynikov, Kathryn Done, Tim Judkins, Allison Dimartino, Jonathan Morse, Lawton N. Verner

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention relates to a laparoscopic apparatus. The apparatus includes a handle having a body portion, a top surface, opposite bottom surface, a proximal and distal end. The top surface of the base is contoured to compliment the natural curve of the palm. The apparatus further includes a shaft projecting from the distal end of the handle. The shaft has a proximal and distal end. A control sphere is located on the handle. The control sphere can be moved by one or more of a user's fingers to indicate direction. An end effector is located at the distal end …

Simulation Of Vertical Axis Wind Turbines With Variable Pitch Foils, L. Damon Woods, John F. Gardner, Kurt S. Myers

Mechanical and Biomedical Engineering Faculty Publications and Presentations

A dynamic computer model of a turbine was developed in MATLAB in order to study the behavior of vertical axis wind turbines (VAWTs) with variable pitch (articulating) foils. The simulation results corroborated the findings of several empirical studies on VAWTs. The model was used to analyze theories of pitch articulation and to inform the discussion on turbine design. Simulations of various models showed that pitch articulation allowed Darrieus-style vertical axis wind turbines to start from rest. Once in motion, the rotor was found to accelerate rapidly to very high rotational velocities. The simulations revealed a plateau region of high efficiency …

Oil Droplet Behavior At A Pore Entrance In The Presence Of Crossflow: Implications For Microfiltration Of Oil-Water Dispersions, Nikolai V. Priezjev, Tohid Darvishzadeh, Volodymyr V. Taravara

Mechanical and Materials Engineering Faculty Publications

The behavior of an oil droplet pinned at the entrance of a micropore and subject to clossflow-induced shear is investigated numerically by solving the Navier-Stokes equation. We found that in the absence of crossflow, the critical transmembrane pressure required to force the droplet into the pore is in excellent agreement with a theoretical prediction based on the Young-Laplace equation. With increasing shear rate, the critical pressure of permeation increases, and at sufficiently high shear rates the oil droplet breaks up into two segments. The results of numerical simulations indicate that droplet breakup at the pore entrance is facilitated at lower …

Implementing The Surface Response To Excitation Method (Sure) With Non-Contact Sensors, Sergio R. Gonzalez Jr.

FIU Electronic Theses and Dissertations

Structural health monitoring (SHM) systems generally install low cost excitation component and/or sensors to the machines or buildings permanently to monitor the health of it. Non Destructive Evaluation (NDE) systems use high cost sensors to perform the inspection of structures. It would be advantageous to inspect the some aerospace structures and parts in vacuum environment by using the remotely monitoring systems such as laser vibrometer. In this study, a scanning laser vibrometer is used to detect the location of the problem at the structure. For data collection and analysis recently, developed surface response to excitation (SuRE) method was used.

First …

Development Of A Coupling Model For Fluid-Structure Interaction Using The Mesh-Free Finite Element Method And The Lattice Boltzmann Method, Jaime Mudrich

FIU Electronic Theses and Dissertations

In the presented thesis work, the meshfree method with distance fields was coupled with the lattice Boltzmann method to obtain solutions of fluid-structure interaction problems. The thesis work involved development and implementation of numerical algorithms, data structure, and software. Numerical and computational properties of the coupling algorithm combining the meshfree method with distance fields and the lattice Boltzmann method were investigated. Convergence and accuracy of the methodology was validated by analytical solutions.

The research was focused on fluid-structure interaction solutions in complex, mesh-resistant domains as both the lattice Boltzmann method and the meshfree method with distance fields are particularly adept …

Development Of A Body For A Pneumatic Crawler For Radioactive Waste Pipelines, Jose Alfonso Matos

FIU Electronic Theses and Dissertations

The goal of this thesis was to develop a body for a crawler robot to navigate DOE Hanford Site transfer pipelines in a timely fashion. Previous work in pipe crawlers was analyzed and different configurations were studied by this author in order to design a suitable device. Tests were done in CAD to verify the device would fit and be able to travel within the confines of the pipelines’3” inner diameter and 90° elbows with 4.25”radii. Pipelines in Hanford can transition into 2” pipe and this was also taken into consideration when selecting the dimensions for the device. Manufacturing methods …

Mems Fabrication Process Base On Su-8 Masking Layers, Scott A. Ostrow, Ronald A. Coutu Jr.

AFIT Patents

A novel fabrication process uses a combination of negative and positive photoresists with positive tone photomasks, resulting in masking layers suitable for bulk micromachining high-aspect ratio microelectromechanical systems (MEMS) devices. This technique allows the use of positive photomasks with negative resists, opening the door to an ability to create complementary mechanical structures without the fabrication delays and costs associated with having to obtain a negative photomask. In addition, whereas an SU-8 mask would normally be left in place after processing, a technique utilizing a positive photoresist as a release layer has been developed so that the SU-8 masking material can …

A Finite Element Model Based On Coupled Refined High-Order Global-Local Theory For Static Analysis Of Electromechanical Embedded Shear-Mode Piezoelectric Sandwich Composite Beams With Various Widths, S.B. Beheshti-Aval, S. Shahvaghar-Asl, M. Lezgy-Nazargah, Mohammad N. Noori

Mechanical Engineering

In this study, a new theory for the accurate simulation of the shear-mode behaviour of thin or thick piezoelectric sandwich composite beams is developed. The effects of transverse normal stress and transverse flexibility of layers are considered in the development of the proposed formulation. In order to increase the computational accuracy, all kinematic and stress continuity conditions are satisfied at layer interfaces. Moreover, for the first time, both the electrically induced strain components and the transverse flexibility are taken into account in the proposed formulation. Despite the fact that the number of unknown mechanical parameters in this theory is only …

Load Path Uncertainty In A Wood Structure And The Effect On Structural Reliability, Wenqi Wang, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The roof truss bearing points of a light-framed wood house were instrumented with load cells. It was found that under dead load alone, symmetric and theoretically identical truss reactions have significant variation. A similar degree of reaction discrepancy was found under the application of uplift pressures caused by hurricane winds. Analysis revealed that the majority of this discrepancy is caused by inherent uncertainties in load path. Although uncertainties in load magnitude and material resistance are accounted for in design by use of appropriate load and resistance factors, load path is generally taken to be deterministic. In this study, load path …

Reliability Analysis Of Reinforced Concrete Columns Exposed To Fire, Christopher D. Eamon, Elin A. Jensen

Civil and Environmental Engineering Faculty Research Publications

A reliability analysis is conducted on reinforced concrete columns subjected to fire load. From an evaluation of load frequency of occurrence, load random variables are taken to be dead load, sustained live load, and fire temperature. Resistance is developed for axial capacity, with random variables taken as steel yield strength, concrete compressive strength, placement of reinforcement, and section width and height. A rational interaction model based on the Rankine approach is used to estimate column capacity as a function of fire exposure time. Various factors were considered in the analysis such as fire type, load ratio, reinforcement ratio, cover, concrete …