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Articles 1 - 9 of 9
Full-Text Articles in Electro-Mechanical Systems
A Review Of Variable Valve Timing Devices, Paul Shelton
A Review Of Variable Valve Timing Devices, Paul Shelton
Mechanical Engineering Undergraduate Honors Theses
Variable valve timing (VVT) has evolved from simple, manual controlled engine management to automatic, electronic works of engineering. Starting from the need for more power and extending into fuel efficiency and low emissions, VVT has evolved from the constant changing of needs. This paper summarizes various devices used to control the timing of valves from the early 1920s up until 2007.
Restart Capabilities Of Hybrid Rocket Motor Utilizing Gaseous Propane And Oxygen Injection System, Joseph Gracy
Restart Capabilities Of Hybrid Rocket Motor Utilizing Gaseous Propane And Oxygen Injection System, Joseph Gracy
Mechanical Engineering Undergraduate Honors Theses
Hybrid rockets have become an increasingly popular application in professional and amateur rocketry for their outstanding performance and reliability. An issue pressing the marketability and functionality of these rockets is the ability to restart with an exclusive system after primary ignition. Research and development of a system that can be used reliably in either application to achieve restart under various conditions has been made recently using dual injection of GOX and C3H8 using a 200kV ignition system while implementing a polymethylmethacrylate (PMMA) formable polymer as primary fuel. The system used a manual valve arrangement for control. The design features most …
Development Of Miniature Hybrid Rockets For Orbital Upkeep And Transfer Applications In Nano/Pico-Satellites, Derek Willingham
Development Of Miniature Hybrid Rockets For Orbital Upkeep And Transfer Applications In Nano/Pico-Satellites, Derek Willingham
Mechanical Engineering Undergraduate Honors Theses
This research has developed and constructed a successful miniature hybrid rocket test assembly for research into hybrid rocket scaling issues. It is hoped that such systems will find eventual integration into small satellites. The test assembly houses 3" fuel grains and provides an inlet for gaseous oxidizer. Although far from complete, preliminary data were taken with PMMA and GOx and some useful conclusions were drawn that will benefit future research into this topic. Fuel grains with combustion chambers whose diameters range from 1/16" to 3/8" were tested at different flow rates and thrust data gathered. Maximum flow information was gathered …
Development And Validation Of A Dynamic Model Of The Maglev Transportation System At Old Dominion University, Ajinkya V. Deodhar
Development And Validation Of A Dynamic Model Of The Maglev Transportation System At Old Dominion University, Ajinkya V. Deodhar
Mechanical & Aerospace Engineering Theses & Dissertations
A dynamic model for the vehicle-guideway coupled with a controller is developed using dynamic modelling software, MADYMO. The fundamental characteristics of the vehicle are obtained from detailed FE analysis in NASTRAN. The vehicle is then converted into a 21-degree-of-freedom rigid body system with 12 FE magnets. A two span concrete guideway of 54 meters in length is modelled using 3D solid Hex8 elements. The air gap is modelled as a penetration of the magnets in the guideway. The PD controller aims at achieving constant penetration (i.e. the air gap) of all magnets in the guideway, throughout the simulation. This PD …
Electrically Steerable Diffraction Gratings For Hyperspectral Imaging: A Microelectromechanical System Design And Fabrication, Saban Atinc Delican
Electrically Steerable Diffraction Gratings For Hyperspectral Imaging: A Microelectromechanical System Design And Fabrication, Saban Atinc Delican
Theses and Dissertations
The current research is focused on the design and fabrication of an electrically programmable diffraction grating using standard micro electro mechanical systems (MEMS) technology. The goal is to design a beam steering element required to build very small hyperspectral imaging (HSI) sensors. The diffraction grating will be used to perform beam-dispersion - a critical step in the imaging process. The proposed transmissive diffraction grating based approach will minimize the overall size and the number of components in the physical design of the hyperspectral imagers, thereby enabling us to exploit the traditional advantages of MEMS such as increased reliability, smaller size, …
Factors Affecting The Spread Of A Bioterrorist Agent Throughout A Building, William A. Cantrell
Factors Affecting The Spread Of A Bioterrorist Agent Throughout A Building, William A. Cantrell
Inquiry: The University of Arkansas Undergraduate Research Journal
Bioterrorism has become a greater concern for Americans since the 2001 anthrax letters. Recent studies have explored the possibilities of biological attacks, and most deal with possible large-scale attacks. However, there is reason to believe that small-scale attacks are more likely. Even though there have been investigations of the postal delivery system and the spread of bioagents through mail, few if any studies have looked at attack on a single building and the resultant spread form room to room. One particular method of attacking a building would be a single-even release of an aerosol bioagent in the building. This paper …
Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey
Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey
Faculty Publications
This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (RX) and quality factor (Q) with the resonators’ silicon layer thickness (tSi). For identical lateral dimensions and PZT-layer thicknesses (tPZT), the PZT-on-silicon resonator has higher resonant frequency (fC), higher Q (5100 versus 140), lower RX (51 Ω versus 205 Ω), and better linearity [third-order input intercept …
Analysis Of Wind Turbine Transverse Vibration, Matt Hein, Whitney Karpen
Analysis Of Wind Turbine Transverse Vibration, Matt Hein, Whitney Karpen
The Journal of Undergraduate Research
Large wind turbines have become an appealing choice for renewable electrical energy production throughout the world. The United States Midwest contains massive potential for wind energy development and is therefore being primed for large wind turbines to harvest this resource and bring it to market. Because of this, safety concerns have arisen in regard to their ability to withstand the harsh climate of the region. Analysis of the transverse vibration caused by severe weather will be preformed. A simplified model will allow for an analytical solution and displacement graphs produced with MATLAB code. This information will allow for an unbiased …
Development And Validation Of A Dynamic Model Of The Maglev Transportation System At Old Dominion University, Ajinkya Deodhar, Sebastian Bawab, Aravind Hanasoge
Development And Validation Of A Dynamic Model Of The Maglev Transportation System At Old Dominion University, Ajinkya Deodhar, Sebastian Bawab, Aravind Hanasoge
Mechanical & Aerospace Engineering Faculty Publications
A dynamic model of the vehicle/guideway coupled with a controller is developed for the maglev demonstration system currently being developed at ODU, using the MAthematical DYnamic MOdeling software - MADYMO. The fundamental characteristics of the vehicle and guideway are obtained from detailed finite element analyses using MSC-NASTRAN. As a result, the vehicle is modeled in MADYMO as a 21- degree-of-freedom spring-mass-damper system. A three span concrete guideway is modeled using 3D solid Hex8 elements. The air gap is modeled as a penetration of the magnets into the guideway. Decentralized colocated PD controllers are used for controlling the penetration of each …