Engineering Commons^™

Mavericks & 2007 International Civilian Space Competition, Thomas M. Atchison

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Thomas M. Atchison titled "Mavericks & 2007 International Civilian Space Competition" from September 22, 2006.

Performance Of Algebraic Multigrid For Parallelized Finite Element Dns/Les Solvers, Gregory James Larson

Theses and Dissertations

The implementation of a hybrid spectral/finite-element discretization on the unsteady, incompressible, Navier-Stokes equations with a semi-implicit time-stepping method, an explicit treatment of the advective terms, and an implicit treatment of the pressure and viscous terms leads to an algorithm capable of calculating 3D flows over complex 2D geometries. This also results in multiple Fourier mode linear systems which must be solved at every timestep, which naturally leads to two parallelization approaches: Fourier space partitioning, where each processor individually and simultaneously solves a linear system, and physical space partitioning, where all processors collectively solve each linear system, sequentially advancing through Fourier …

Analysis Of A K-Out-Of-N System With Spares, Repairs, And A Probabilistic Rule, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a k-out-of-N reliability system with identical components having exponential lifetimes. There is a single repairman who attends to failed components on a first comefirst-served basis. The repair times are assumed to be of phase type. The system has K spares that can be used according to a probabilistic rule to extend the lifetime of the system. The system is analyzed using Markov chain theory and some interesting results are obtained. A few illustrative numerical examples are discussed.

Numerical Simulation Of Plasma-Based Actuator Vortex Control Of A Turbulent Cylinder Wake, Nathan Keith Mcmullin

Theses and Dissertations

A numerical study has been performed to investigate the mechanics of the turbulent wake of a circular cylinder that is controlled by a plasma actuator. The numerical investigation implements a straightforward moving wall boundary condition to model the actuator's effects on the flow. Validations of the moving wall for this simulation are set forth with the understanding that the moving wall can model the plasma actuator bulk flow effects at a distance downstream and not in a region near or on the plasma actuator. The moving wall boundary condition is then applied to a circular cylinder at a Reynolds number …

Obstacle Avoidance For Small Unmanned Air Vehicles, Brandon R. Call

Theses and Dissertations

Small UAVs are used for low altitude surveillance flights where unknown obstacles can be encountered. These UAVs can be given the capability to navigate in uncertain environments if obstacles are identified. This research presents an obstacle avoidance system for small UAVs. First, a mission waypoint path is created that avoids all known obstacles using a genetic algorithm. Then, while the UAV is in flight, obstacles are detected using a forward looking, onboard camera. Image features are found using the Harris Corner Detector and tracked through multiple video frames which provides three dimensional localization of the features. A sparse three dimensional …

Low-Frequency Ultrasound Increases Outer Membrane Permeability Of Pseudomonas Aeruginosa, Christopher M. Runyan, John C. Carmen, Benjamin L. Beckstead, Jared L. Nelson, Richard A. Robison, William G. Pitt

Faculty Publications

Low-frequency ultrasound has been investigated as an adjuvant to antimicrobial therapy, targeted at both planktonic and biofilm (sessile) organisms. Our previous work showed that ultrasound (US) effectively enhances the bactericidal activity of certain antibiotics against planktonic cultures (Pitt et al., 1994; Rediske et al., 1999) and in vitro biofilms (Johnson et al., 1998; Qian et al., 1999) and in vivo biofilms (Carmen et al., 2004b, 2005; Rediske et al., 2000) of gram-positive and gram-negative bacteria. Ultrasound was shown to increase the transport of antibiotics through biofilms (Carmen et al., 2004a) which could account for some (or all) of the enhanced …

Magnetic Nanoparticle Supported Catalyst For Atom Transfer Radical Polymerization, Shijie Ding, Yangchuan Xing, Maciej Radosz, Youqing Shen

Chemical and Biochemical Engineering Faculty Research & Creative Works

Magnetic nanoparticles were used to support an ATRP catalyst for the polymerization of methyl methacrylate (MMA) for minimized adverse effect of catalyst support and easy catalyst separation. the nanoparticle-supported catalyst mediated a living/controlled radical polymerization of MMA as effectively as unsupported catalysts. with the addition of 22 mol % of CuBr 2, the polymer molecular weights were well-controlled with an initiator efficiency of 0.85 and polydispersity lower than 1.2. the supported catalysts could be easily separated/isolated using an external magnetic field and reused with slightly decreased activity but further improved control. the activity of the recycled catalyst was regenerated by …

Pneumatic Tire, Alan Neville Gent, Joseph D. Walter

Mechanical Engineering Faculty Research

For many years, tire engineers relied on the monograph, 'Mechanics of Pneumatic Tires', for detailed information about the principles of tire design and use. Published originally by the National Bureau of Standards, U.S. Department of Commerce, in 1971, and a later (1981) edition by the National Highway Traffic Safety Administration (NHTSA), U.S. Department of Transportation, it has long been out of print. No textbook or monograph of comparable range and depth has appeared since. While many chapters of the two editions contain authoritative reviews that are still relevant today, they were prepared in an era when bias ply and belted-bias …

Debt Ratio Analysis Of Taiwan??Property Development Firms Under Contraction, Chao-Hui Wu, Ting-Ya Hsieh

Journal of Marine Science and Technology–Taiwan

This study analyzes the correlation between debt ratios and corporate performance of the property development firm during times of contraction in Taiwan. This study collects and examines financial data for the period 1992 to 2003 for 25 listed property development firms. A total of 16 financial ratios, collectively representing corporate performance, were statistically checked with three types of debt ratios. The comparison results reveal that profitability related ratios are inadequate representations of corporate performance. Especially, investors consider a vigorous dividends policy to indicate a crisis. Two positive directions for property development firms during a contraction include (1) product differentiation and …

Dynamic Relationship Of Steel Prices Between Two Different Markets:Taiwan And Mainland China, Yong-Huang Lin, Yun-Wu Wu

Journal of Marine Science and Technology–Taiwan

Price variation is one of the major factors taken into account in cost control decision in construction projects. Previous researches have focused on the short-term price prediction of a merchandise within a closed single market without considering the long-term effect by interacting with other markets. The econometric methods such as structural break test, co-integration analysis, and Granger causality test were used to examine the dynamic short-term and long-term relationships of steel prices between two different markets, Taiwan and China, over the period of 1995 ~ 2004. The steel price of China was found to have the leading discovery function by …

Determining The Repair Ranking Of Existing Rc Bridges Using Least Squares Technique Associated With Comparison Matrix Method, Ming-Te Liang, Chin-Ming Lin, Wen-Hu Tsao, Chi-Jang Yeh

Journal of Marine Science and Technology–Taiwan

The principal objective of this paper is employed the least squares technique associated with comparison matrix method to determine the repair ranking of existing reinforced concrete (RC) bridges with bestridden or non-bestridden river. Six existing RC bridges in Taiwan are given as an illustrative example. For verifying the feasibility and reliability of the proposed method, the D (Degree) E (Extent) R (Relevancy) evaluation method, which is only considered the RC bridges built on river bed and is now widely used to evaluate the damage grade for existing RC bridges in Taiwan, is also adopted to assessing the same six existing …

Mössbauer And Epr Spectra For Glasses And Glass-Ceramics Prepared From Simulated Compositions Of Lunar And Martian Soils, C. S. Ray, Signo Tadeu Dos Reis, W. M. Pontuschka, J. B. Yang, F. F. Sene, J. M. Giehl, Chang-Soo Kim, S. Sen

Materials Science and Engineering Faculty Research & Creative Works

In situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using Lunar and Martian soils and exploring various application potentials of these materials for planetary surface operations. This paper reports the successful preparation of glasses from the melts of simulated composition of Lunar and Martian soils, and thermal and structural characterization using differential thermal analysis (DTA), Mössbauer and electron paramagnetic resonance (EPR) spectroscopy. Glass-ceramic materials were developed from these glasses using selective …

Minimizing The Makespan In A Two-Stage Flowshop Scheduling Problem With A Function Constraint On Alternative Machines, Chou-Jung Hsu, Wen-Hung Kuo, Dar-Li Yang, Maw-Sheng Chern

Journal of Marine Science and Technology–Taiwan

In this paper, we consider a two-stage flowshop scheduling problem with a function constraint on alternative machines. The objective is to minimize the makespan. We show that the proposed problem is NP-hard and provide some heuristic algorithms and computational experiments. In addition, from the experimental results, the modification of Johnson’s rule combined with the First-Fit rule is the best heuristic algorithm of the proposed heuristic algorithms.

Wavelet-Based Shift-Invariant Noise Model, Fu-Tai Wang, Jenny Chih-Yu Lee, Shun-Hsyung Chang

Journal of Marine Science and Technology–Taiwan

This paper proposes the use of shift-invariant dual-tree discrete wavelet transform (DT DWT) noise model to the problem of a multipath signal detection in underwater environment. The design procedure for this adaptive model of the background noise is described. When an input signal is shifted, as in a multipath environment, this shift-invariant DT DWT can generate multi-resolution subspaces. Each of them keeps more coefficient energy of this signal than DWT’s. The result of computer simulations shows that this method can improve the performance of a multipath signal detection, by reducing the false alarm probability in a range of different signal-tonoise …

Determining The Repair Ranking Of Existing Rc Bridges Using Least Squares Technique Associated With Comparison Matrix Method, Ming-Te Liang, Chin-Ming Lin, Wen-Hu Tsao, Chi-Jang Yeh

Journal of Marine Science and Technology–Taiwan

The principal objective of this paper is employed the least squares technique associated with comparison matrix method to determine the repair ranking of existing reinforced concrete (RC) bridges with bestridden or non-bestridden river. Six existing RC bridges in Taiwan are given as an illustrative example. For verifying the feasibility and reliability of the proposed method, the D (Degree) E (Extent) R (Relevancy) evaluation method, which is only considered the RC bridges built on river bed and is now widely used to evaluate the damage grade for existing RC bridges in Taiwan, is also adopted to assessing the same six existing …

Averaged Inertia Principle For Non-Newtonian Squeeze Films In Wide Parallel Plates: Couple Stress Fluid, Jaw-Ren Lin, Chi-Ren Hung, Rong-Fang Lu

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the combined effects of non-Newtonian couple stresses and convective fluid inertia forces upon the squeeze film characteristics of two wide parallel plates are investigated by using the averaged inertia principle. A numerical solution of the film height versus response time is calculated by using the fourth-order Runge-Kutta method. Compared to the Newtonian-lubricant non-inertia case of Hamrock [4], the qualitative effects of couple stresses and convective inertia forces provide an increase in the film pressure, the load capacity and the response time. Moreover, the quantitative effects are more pronounced for wide parallel plates …

Electrochemical Durability Of Carbon Nanotubes In Noncatalyzed And Catalyzed Oxidations, Liang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Noncatalyzed and catalyzed electrochemical oxidations of multiwalled carbon nanotubes (CNTs) were studied with the aim to understand their durability as catalyst support in polymer electrolyte membrane (PEM) fuel cells. Bare and Pt-deposited CNTs were investigated in 1.0 M sulfuric acid at a constant potential of 1.2 V. Carbon black (CB, Vulcan XC-72R) was also studied under the same experimental conditions. the carbons were oxidized at room temperature in the form of thin-film electrodes with time durations up to 48 h. Cyclic voltammetry was used to monitor the surface oxide redox reactions as a way to quantify the degree of surface …

Integrating Design Throughout The Mechanical Engineering Curriculum: A Focus On The Engineering Clinics, Krishan Bhatia, Tirupathi R. Chandrupatla, John C. Chen, Eric Constans, Jennifer A. Kadlowec, Anthony J. Marchese, Paris Von Lockette, Hong Zhang

Mechanical Engineering

At Rowan University, we have infused design into the curriculum through an eight-semester course sequence called the Engineering Clinic. Through this experience students learn the art and science of design in a multidisciplinary team environment. While many engineering programs currently include a Capstone Design course taken near the end of the college career to meet the design needs, Engineering Clinic at Rowan allows students to hone their design skills throughout their four-year career. This paper will describe in further detail the objectives and execution of each year in the design sequence, types of projects and how the Clinics complement traditional …

Method And Apparatus For Timing Recovery Based On Dispersion Characterization And Components, Jaiganesh Balakrishnan, William A. Sethares, Wonzoo Chung, Richard K. Martin

AFIT Patents

The present invention provides a method for generating a timing offset signal applied to a sampling device for recovering a symbol stream from a broadcast signal by characterizing the dispersion of received signal. Preferably, the method includes steps for generating a derivative signal approximating the derivative of the symbol stream, producing a constant representative of an expected symbol stream, and multiplying the derivative signal, the constant, and a signal one of corresponding to and approximating the symbol stream to thereby generate the timing offset signal. A dispersion characterizing receiver and a digital signal processor employed therein are also described.

An Adaptive Tabu Search Heuristic For The Location Routing Pickup And Delivery Problem With Time Windows With A Theater Distribution Application, Robert E. Burks Jr.

Theses and Dissertations

The time constrained pickup and delivery problem (PDPTW) is a problem of finding a set of routes for a fleet of vehicles in order to satisfy a set of transportation requests. Each request represents a user-specified pickup and delivery location. The PDPTW may be used to model many problems in logistics and public transportation. The location routing problem (LRP) is an extension of the vehicle routing problem where the solution identifies the optimal location of the depots and provides the vehicle schedules and distribution routes. This dissertation seeks to blend the PDPTW and LRP areas of research and formulate a …

Analysis Of Gait Characteristics In Mentally Handicapped Individuals, Prakriti Parijat, Jian Liu, Thurmon E. Lockhart, Courtney Haynes

Computer Sciences and Electrical Engineering Faculty Research

Physical and motor dysfunctions in mentally handicapped individuals predispose them to a higher risk of slip and fall accidents. It is estimated that over 60 million people are currently suffering with some level of developmentally related cognitive impairment (American Disability Act ADA, 2000). Mental retardation occurs in 2.5-3% of the general population. About 6-7.5 million mentally retarded individuals live in the United States alone (ADA, 2000). Slip induced fall accidents are a primary source of injury in people with mental retardation (MR). Often, the incidence of falls among this population is compounded by other disabilities such as autism, seizure, and …

Optical Emission In Magnetically Confined Laser-Induced Breakdown Spectroscopy, X. K. Shen, Yongfeng Lu, T. Gebre, Hao Ling, Y. X. Han

Department of Electrical and Computer Engineering: Faculty Publications

Magnetically confined laser-induced breakdown spectroscopy was investigated by studying the optical emission from laser-induced plasma plumes expanding across an external transverse magnetic field. KrF excimer laser pulses with a pulse duration of 23 ns and a wavelength of 248 nm were used to produce plasmas from Al, Cu, and Co targets. Various optical emission lines obtained from Al and Cu targets show an obvious enhancement in the intensity of optical emission when a magnetic field of ~0.8 T is applied, while the optical emission lines from Co targets show a decrease in the optical emission intensity. The enhancement factors of …

Design And Fabrication Of Rotationally Tristable Compliant Mechanisms, Tyler M. Pendleton

Theses and Dissertations

The purpose of this research is to develop the tools necessary to create tristable compliant mechanisms; the work presents the creation of models and concepts for design and a demonstration of the feasibility of the designs through the fabrication of tristable compliant mechanism prototypes on the macro scale. Prior methods to achieve tristable mechanisms rely on detents, friction, or power input; disadvantages to these methods include a high number of parts, the necessity for lubrication, and wear. A compliant tristable mechanism accomplishes tristability through strain energy storage. These mechanisms would be preferable because of increased performance and cost savings due …

Error Allocation In Complex Systems Design, Robert A. Mcdonald

Aerospace Engineering

A fidelity trade environment was conceived, formulated, developed, and demonstrated. This development relied on the advancement of enabling techniques including error propagation, metamodeling, and information management. These techniques were integrated with an existing commercial systems design framework and an intuitive graphical interface to create a fidelity trade environment. A sensitivity approach to the propagation of error through complex systems was developed. This approach relied on the system sensitivity matrix to model the behavior of a complex system as a whole. In verification tests, the sensitivity approach provided approximate results substantially similar to a Monte Carlo approach that was many orders …

2006 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

In the Fall 2006 semester, I challenged the ENGR333 students to “construct a realistic plan to make a significant impact on the Calvin College campus with electrical power generated from wind resources.”

Customer

The customer for this project was Calvin’s VP for finance Henry DeVries.

Lightweight In-Plane Actuated Deformable Mirrors For Space Telescopes, Michael J. Shepherd

Theses and Dissertations

This research focused on lightweight, in-plane actuated, deformable mirrors, with the ultimate goal of developing a 20- meter light gathering aperture for space telescopes. The 0.127 meter diameter deformable mirror small scale testbed was modelled infinite elements using MSC.Nastran software and then used as a basis for a quasi-static controller. Experimental tracking of Zernike tip, tilt, and defocus modes was accomplished. The analytical solutions to plate-membrane and beam-string ordinary differential equations were developed. A simplified approach to modelling the axisymmetric cases was also presented. A novel static control strategy, the Modal Transformation Method, was developed to form Zernike surfaces within …

Automatic, Unstructured Mesh Generation For 2d Shelf Based Tidal Models, Cameron L. Mcdonald

Theses and Dissertations

Numeric models use a collection of triangular facets called elements connected over a domain in what is referred to as a mesh or unstructured grid as the computational basis for calculations. The density of elements in a mesh affects the numeric stability of a model when performing computations. Furthermore, these meshes can be difficult and time consuming to create. This thesis describes an automated process of creating meshes which utilizes local truncation analysis to generate a spatially varied size function. An advancing frontal mesh generation algorithm uses this function to optimize node placement and density. Further analysis to better understand …

Dynamics And Control Of Tethered Satellite Formations For The Purpose Of Space-Based Remote Sensing, Kurt A. Vogel

Theses and Dissertations

This dissertation assesses the utility of tethered satellite formations for the space-based remote sensing mission. Energy dissipation is found to have an adverse effect on foundational rigid body (Likins-Pringle) equilibria. It is shown that a continuously earth-facing equilibrium condition for a fixed-length tethered system does not exist since the spin rate required for the proper precession would not be high enough to maintain tether tension. The range of required spin rates for steady-spin motion is numerically defined here, but none of these conditions can meet the continuously earth-facing criteria. Of particular note is the discovery that applying certain rigid body …

Performance Of A Variable Speed Double-Fed Induction Generator Wind Turbine During Network Voltage Unbalance Conditions, Joseph Kearney, Michael Conlon

Conference papers

The issues of the negative performance of DFIG’s due to supply network voltage unbalance are outlined in this paper. The paper shows the effects that voltage unbalance can have on a DFIG, using the power simulation program DigSilent. The results from simulations show that voltage unbalance affects the both the induction generator and the rotor converter, due to the high unbalanced currents generated. The ability to modify the control strategy of a DFIG to compensate for voltage unbalance is outlined and a proposal to build a test-rig suitable to implement such a system is suggested.

Volumetric Water Pricing, Charles M. Burt

BioResource and Agricultural Engineering

This document discusses the concept of volumetric pricing for irrigation water, including:

1. The justification for paying volumetrically

2. The challenge of charging volumetrically

3. Characteristics of volumetric charges and influencing factors

4. Examples of irrigation projects with volumetric charges

5. A summary of necessary conditions for volumetric billing