Mechanical Engineering Commons^™

Introduction Of Planar Compliant Joints Designed For Combined Bending And Axial Loading Conditions In Lamina Emergent Mechanisms, Samuel E. Wilding, Larry L. Howell, Spencer P. Magleby

Faculty Publications

This work introduces three joints to allow motion in lamina emergent mechanisms (LEMs) that were designed to have minimal parasitic motion under tension, compression, and a combination of tension and compression loading. Closed-form models of the joints were developed and combined with optimization algorithms for maximum flexibility in bending and then modeled using finite element analysis (FEA). The FEA results were used to predict the stiffness of the joints in bending, tension, and compression. As a baseline, lamina emergent torsional (LET) joints were designed to match the bending stiffness of each of the joints, so that the tensile-compressive performance could …

2012 (Fall) Ensi Informer Magazine, Morehead State University. Engineering Sciences Department

ENSI Informer Magazine Archive

The ENSI Informer Magazine published in the fall of 2012.

Thermal And Mechanical Properties Of Nitrate Thermal Storage Salts In The Solid-Phase, Brian D. Iverson, Scott T. Broome, Alan M. Kruizenga, Joseph G. Cordaro

Faculty Publications

Implementation of molten salt compounds as the heat transfer fluid and energy storage medium provides specific benefits to energy collection and conversion. Nitrate salts have been identified as a strong candidate for energy transfer and storage and have been demonstrated for use in these applications over time. As nitrate salts have solidification temperatures above ambient, concern for recovery from salt freezing events has instigated efforts to understand and predict this behavior. Accurate information of salt property behavior in the solid-phase is necessary for understanding recovery from a freeze event as well as for phase change thermal energy storage applications. Thermal …

Atomistic Investigation Of Scratching-Induced Deformation Twinning In Nanocrystalline Cu, Junjie Zhang, Tao Sun, Yoganda Yan, Dong Shen, Xiaodong Li

Faculty Publications

Deformation twinning is an important deformation mode of nanocrystalline metals. In current study, we investigate the scratching-induced deformation twinning in nanocrystallineCu by means of molecular dynamics simulations. The tribological behavior, the deformation mechanisms, the formation mechanism of deformation twins, and the grain size dependence of the propensity of deformation twinning are elucidated. Simulation results demonstrate that deformation twinning plays an important role in the plastic deformation of nanocrystallineCu under nanoscratching, in addition to dislocation activity and grain boundary-associated mechanism. The nucleation of initial twinning partial dislocations originates from the dissociation of lattice partial dislocations that emit from grain boundary triple …

Designing For Success: Developing Engineers Who Consider Universal Design Principles, Kimberly Edginton Bigelow

Mechanical and Aerospace Engineering Faculty Publications

Engineers must design for a diverse group of potential users of their products; however, engineering curricula rarely include an emphasis on universal design principles. This research article details the effectiveness of a design project implemented in a first-year engineering course in an effort to raise awareness of the need for engineers to be more inclusive when designing. Students were asked to apply universal design principles to redesign an engineering laboratory to make it more usable to all, including individuals with disabilities who use the room. A representative from the university’s disability services staff, as well as individuals with first-hand experience …

Powered Transtibial Prosthetic Device Control System Design, Implementation And Testing, Jinming Sun

Master's Theses (2009 -)

A powered lower limb prosthesis, which consists of a four bar mechanism, a torsional spring and a brushed DC motor, was previously designed and fabricated. To regulate the motor power input, a two level controller was proposed and built. The control algorithm includes a higher level finite state controller and lower level PID controllers. To implement the control system, a digital signal processor (DSP) control board and MATLAB Simulink were used to realize the higher level control and a DC motor controller was used to realize the lower level PID control. Sensors were selected to provide the required feedback. The …

Development Of A Supervisory Control Unit For A Series Plug-In Hybrid Electric Vehicle, Brian Neal Harries

Doctoral Dissertations and Master's Theses

A Series PHEV was chosen, as ERAU's entry into EcoCAR2 through a multidisciplinary architecture selection process. The series architecture was chosen for its mechanical feasibility, consumer acceptability and its performance on energy consumption simulations. The Series PHEV architecture was modeled using Matlab, Simulink, and dSPACE ASM tools, to create a plant model for controller development. A supervisory controller was developed to safely control the interactions between powertrain components. The supervisory control unit was tested using SIL and HIL methodologies. The supervisory controller was developed with an emphasis on fault detection and mitigation for safety critical systems. A power management control …

Finite Element Model Updating For Rotary Machinery, Nathalie Gotin

Master's Theses

The main approach of this thesis was to develop a mathematical model that represents a rotary machine. Experimental data was used to define a finite element model (FEM). In order to obtain the experimental data, the rotary machine had to be balanced. An impact hammer test made it possible to obtain frequency response functions (FRF). The frequency response functions were curvefitted in order to obtain the mode shapes and natural frequencies.

Mathematical models have been created with ABAQUS and Matlab. For the Matlab Model the assumption has been made that the rotor machine consists of a specific number of beam …

One-Step Synthesis Of Dimethyl Ether From The Gas Mixture Containing Co2 With High Space Velocity, Wei-Hsin Chen

Wei-Hsin Chen

No abstract provided.

Entropy Generation From Hydrogen Production Of Catalytic Partial Oxidation Of Methane With Excess Enthalpy Recovery, Wei-Hsin Chen

Wei-Hsin Chen

No abstract provided.

تمرين سري اول, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Enhanced Methanol Oxidation And Co Tolerance Using Ceo2-Added Eggshell Membrane-Templated Pd Network Electrocatalyst, Qunwei Tang, Zhengping Mao, Shuguo Ma, Kevin Huang

Faculty Publications

Macroporous Pd and CeO₂-added Pd network catalysts have been synthesized using eggshell membrane (ESM) as a template for enhanced methanol oxidation and CO tolerance. The microstructural characterization revealed a hierarchically ordered macroporous network of Pd reproducing the fibrous structure of ESM for a Pd-only catalyst, and a flower-like CeO₂-decorated Pd morphological architecture for the CeO₂-added Pd catalyst synthesized by a precipitation method. XRD patterns indicated Pd and CeO₂ phases with good crystallinity. The cyclic voltammetry studies showed an enhanced electrocatalytic activity for methanol oxidation in acidic aqueous medium. Because of the preferential formation …

A Comparison Of Homes Built To The 2009 And 1984 Florida Energy Codes, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

The Florida Solar Energy Center conducted research into the effectiveness of the Florida energy code to reduce energy use in residential buildings. FSEC examined two groups of homes: those built to the 1984 energy code (June 1,1984-1985) and those built to the 2007 with 2009 supplement energy code (March 1, 2009-2010). This report discusses data collection methods, analysis and results that focus on comparisons of measured energy use and house characteristics between both code periods.

Liquid Jet Impingement Experiments On Micro Rib And Cavity Patterned Superhydrophobic Surfaces In Both Cassie And Wenzel States, Michael G. Johnson

Theses and Dissertations

Experiments were performed to characterize hydraulic jumps that form due to liquid jet impingement on superhydrophobic surfaces with alternating micro-ribs and cavities. If the surface is unimmersed, a surface tension based transition into droplets occurs, so a known depth of water was imposed downstream from the hydraulic jump to ensure the existence of a hydraulic jump. The surfaces are characterized by the cavity fraction, which is defined as the width of a cavity divided by the combined width of a cavity and an adjoining rib. Four different surface designs were studied, with respective cavity fractions of 0 (smooth surface), 0.5, …

Effects Of Haptic And 3d Audio Feedback On Pilot Performance And Workload For Quadrotor Uavs In Indoor Environments, Robert Mark Philbrick

Theses and Dissertations

Indoor flight of unmanned aerial vehicles (UAVs) has many applications in environments in which it is undesirable or dangerous for humans to be, such as military reconnaissance or searching for trapped victims in a collapsed building. However, limited visual feedback makes it difficult to pilot UAVs in cluttered and enclosed spaces. Haptic feedback combined with visual feedback has shown to reduce the number of collisions of UAVs in indoor environments; however, it has increased the mental workload of the operator. This thesis investigates the potential of combining novel haptic and 3D audio feedback to provide additional information to operators of …

An Experimental Investigation Of Strain Rate, Temperature And Humidity Effects On The Mechanical Behavior Of A Perfluorosulfonic Acid Membrane, Zongwen Lu, Melissa Lugo, Michael H. Santare, Anette M. Karlsson, F. Colin Busby, Peter Walsh

Mechanical Engineering Faculty Publications

The time-dependent hygro-thermal mechanical behavior of a perfluorosulfonic acid (PFSA) membrane (Nafion^® 211 membrane) commonly used in Proton Exchange Membrane Fuel Cells (PEMFCs) is investigated at selected strain rates for a broad range of temperatures and humidities. Tensile tests and relaxation tests are conducted to determine Young’s modulus and proportional limit stress as functions of strain rate, temperature and humidity. The results show that Young’s modulus and proportional limit stress increase as the strain rate increases, and decrease as the temperature or humidity increases. The results also show that the mechanical response of Nafion^® 211 membrane is more …

Effect Of Time-Dependent Material Properties On The Mechanical Behavior Of Pfsa Membranes Subjected To Humidity Cycling, Narinder S. Khattra, Anette M. Karlsson, Michael H. Santare, Peter Walsh, F. Colin Busby

Mechanical Engineering Faculty Publications

A viscoelastic-plastic constitutive model is developed to characterize the time-dependent mechanical response of perfluorosulphonic acid (PFSA) membranes. This model is then used in finite element simulations of a representative fuel cell unit, (consisting of electrodes, gas diffusion layer and bipolar plates) subjected to standardized relative humidity (RH) cycling test conditions. The effects of hold times at constant RH, the feed rate of humidified air and sorption rate of water into the membrane on the stress response are investigated. While the longer hold times at high and low humidity lead to considerable redistribution of the stresses, the lower feed and sorption …

Platinum Nanocatalytic Combustion Of Methanol-Air Mixture, James Applegate

Theses and Dissertations

Catalytic combustion's ability to release the potential energy of high energy density fuels could transform the portable electronic device market by removing the reliance on batteries. Catalytic combustion is a generally well understood combustion technique, but the effects of specific experimental conditions (catalyst loading, flow rates and substrates) on catalyst performance are not as well known. Systhesized catalytic Pt nonoparticles (dp ~ 11.6 nm) were dispersed on a cordierite substrate and were characterized using TEM, XRD and SEM. Experimental results were obtained in a miniature-scale continuous flow reactor. Subsequent studies report the effect catalyst loading and reactor flow parameters have …

Molecular Dynamics Simulations Of Oscillatory Couette Flows With Slip Boundary Conditions, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the …

Large Excitonic Effects In Monolayers Of Molybdenum And Tungsten Dichalcogenides, Ashwin Ramasubramaniam

Mechanical and Industrial Engineering Faculty Publication Series

Quasiparticle band structures and optical properties of MoS2, MoSe2, MoTe2, WS2, and WSe2 monolayers are studied using the GW approximation in conjunction with the Bethe-Salpeter equation (BSE). The inclusion of two-particle excitations in the BSE approach reveals the presence of two strongly bound excitons (A and B) below the quasiparticle absorption onset arising from vertical transitions between a spin-orbit-split valence band and the conduction band at the K point of the Brillouin zone. The transition energies for monolayer MoS2, in particular, are shown to be in excellent agreement with available absorption and photoluminescence measurements. Excitation energies for the remaining monolayers …

Large Excitonic Effects In Monolayers Of Molybdenum And Tungsten Dichalcogenides, Ashwin Ramasubramaniam

Ashwin Ramasubramaniam

Energy Storage Characteristics Of A New Rechargeable Solid Oxide Iron-Air Battery, Xuan Zhao, Nansheng Xu, Xue Li, Yunhui Gong, Kevin Huang

Faculty Publications

Cost effective and large scale energy storage is critical to renewable energy integration and smart-grid energy infrastructure. Rechargeable batteries have great potential to become a class of cost effective technology suited for large scale energy storage. In this paper, we report the energy storage characteristics of a newly developed rechargeable solid oxide iron–air battery. Investigations of the battery’s performance under various current densities and cycle durations show that iron utilization plays a determining role in storage capacity and round-trip efficiency. Further studies of the battery's cycle life reveal a unique charge-cycle originated degradation mechanism that can be interpreted by a …

Studying The Effect Of Laser Welding Parameters On The Quality Of Zek100 Magnesium Alloy Sheets In Lap Joint Configuration, Masoud Harooni, Fanrong Kong, Blair Carlson, Radovan Kovacevic

Mechanical Engineering Research

Magnesium, as the lightest structural metal, has been widely used in the automotive and aerospace industries. Porosity is the main issue in the welding of magnesium alloys and can be caused by surface coatings, hydrogen gas, pre-existing porosity, the collapse of an unstable keyhole and vaporization of alloying elements. In this study, the effect of the oxide layer on pore generation in the welding of AZ31B-H24 magnesium alloy is investigated. A fiber laser with a power of up to 4 kW is used to weld samples in a lap joint configuration. Two groups of samples are studied: as received (AR) …

Mitigation Of Pore Generation In Laser Welding Of Magnesium Alloy Az31b In Lap Joint Configuration, Masoud Harooni, Fanrong Kong, Blair Carlson, Radovan Kovacevic

Mechanical Engineering Research

Magnesium, as the lightest structural metal, has been widely used in the automotive and aerospace industries. Porosity is the main issue in the welding of magnesium alloys and can be caused by surface coatings, hydrogen gas, pre-existing porosity, the collapse of an unstable keyhole and vaporization of alloying elements. In this study, the effect of the oxide layer on pore generation in the welding of AZ31B-H24 magnesium alloy is investigated. A fiber laser with a power of up to 4 kW is used to weld samples in a lap joint configuration. Two groups of samples are studied: as received (AR) …

Best Source For Patent Drawing Rules & Regulations, Bernadette Marshall

Bernadette Marshall

It is with great pleasure that I announce something new from NBG-Drafting and Design. This is our first Newsletter - Special Edition; In this edition we will cover our preferred sources for patent drawing rules & regulations. Finding resources for information regarding patent drawing rules can be frustrating. Much of the information refers to out-of-date methods, like hand drawings using ink pens on board. It is hard to imaging creating any type of mechanical/technical drawings today without the use of CADD (software application for computer aided design and drafting). Most skilled patent draftspersons today are practicing in CADD.

My Lecture Notes (Heat Transfer - Chapter 1), Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Maximal Force Characteristics Of The Ca2+-Powered Actuator Of Vorticella Convallaria, Sangjin Ryu, Matthew J. Lang, Paul Matsudaira

Department of Mechanical and Materials Engineering: Faculty Publications

The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca²⁺ binding to generate contractile forces of ~10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical force and work of the spasmoneme depended on the stalk length, i.e., the maximum tension (150–350 nN) and work linearly depended on the stalk length (~2.5 nN and ~30 fJ per 1 mm of the stalk). This stalk-length dependency suggests that motor units of …

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 …

A Method To Generate Pressure Gradients For Molecular Simulation Of Pressure-Driven Flows In Nanochannels, Zhi Liang, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the Difficulties in Molecular Simulation of Pressure-Driven Fluid Flow in Nanochannels is to Find an Appropriate Pressure Control Method. When Periodic Boundary Conditions (PBCs) Are Applied, a Gravity-Like Field Has Been Widely Used to Replace Actual Pressure Gradients. the Gravity-Fed Method is Not Only Artificial, But Not Adequate for Studying Properties of Fluid Systems Which Are Essentially Inhomogeneous in the Flow Direction. in This Paper, a Method is Proposed Which Can Generate Any Desired Pressure Difference to Drive the Fluid Flow by Attaching a "Pump" to the Nanofluidic System, While the Model is Still Compatible with PBCs. the …

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

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.