Engineering Commons^™

An Experimental Study Of Flow Control Techniques On A Multi-Element Airfoil, Ira James Walker

Mechanical & Aerospace Engineering Theses & Dissertations

The results of a wind tunnel experiment are reported, which investigated two different flow control techniques that demonstrated the potential of increasing the lift coefficient on a multi-element airfoil. The data also indicated that boundary-layer separation on the trailing-edge flap could be reduced significantly. Results of the investigation revealed that for some test conditions an increased amount of suction occurred on the upper surface of the main element where the flow was attached. One of the techniques that was tested in this investigation involved the use of a pair of piezoelectric devices attached to the model to provide oscillatory motion …

Numerical Study Of Two-Dimensional Secondary Injection Into A Mach 3.5 Freestream, Stephen C. Coghill

Mechanical & Aerospace Engineering Theses & Dissertations

Upstream interaction within a dual-mode scramjet engine is investigated numerically. The upstream interaction is investigated by increasing the freestream-to-injector pressure ratio. The constant area duct and sudden expansion geometries are used to achieve these results. Analysis using the symmetry boundary condition is compared to the full boundary condition for the constant area duct. Numerical analysis of the Mach 3.5 freestream is conducted using normal sonic injection of nitrogen gas to create the upstream interaction. Comparisons, where applicable, are made to experimental results. Due to the high speed of the flowfield, oblique shockwaves are present causing numerical convergence difficult to achieve. …

Development Of An Aggregation Methodology For Risk Analysis In Aerospace Conceptual Vehicle Design, Trina Marsh Chytka

Engineering Management & Systems Engineering Theses & Dissertations

The growing complexity of technical systems has emphasized a need to gather as much information as possible regarding specific systems of interest in order to make robust, sound decisions about their design and deployment. Acquiring as much data as possible requires the use of empirical statistics, historical information and expert opinion. In much of the aerospace conceptual design environment, the lack of historical information and infeasibility of gathering empirical data relegates the data collection to expert opinion.

The conceptual design of a space vehicle requires input from several disciplines (weights and sizing, operations, trajectory, etc.). In this multidisciplinary environment, the …

Influence Of Nanocrystalline Grain Size On The Breakdown Strength Of Ceramic Dielectrics, Yang Ye, Fatih Dogan, E. Schamiloglu, J. Gaudet, P. Castro, M. Roybal, M. Joler, C. Christodoulou, Shi C. Zhang

Materials Science and Engineering Faculty Research & Creative Works

In an effort to develop transmission lines with higher energy storage capabilities for compact pulsed power applications, the University of Missouri-Rolla (UMR) and the University of New Mexico (UNM) have undertaken a collaborative approach to developing and studying ceramic dielectrics. At UMR, the electrical breakdown strength (BDS) of TiO2-based materials is investigated for high energy density applications. The results of research to-date show that dense titania ceramics with nanocrystalline grain size (~200 nm) exhibit significantly higher BDS as compared to ceramics made using coarse grain materials. Processing-microstructure-property relationships in TiO2 systems are found to play a role with respect to …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 3, January 2003, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

A Gentle Introduction To (Or Review Of) Fundamentals Of Chemistry And Organic Chemistry, Dan E. Krane, Michael L. Raymer

Computer Science and Engineering Faculty Publications

Presentation prepared for CS 790: Bioinformatics. The lecture comprises material from the text Fundamental Concepts of Bioinformatics.

Sequence Alignments And Database Searches, Dan E. Krane, Michael L. Raymer

Computer Science and Engineering Faculty Publications

Presentation prepared for Intro to Bioinformatics. The lecture comprises material from the text Fundamental Concepts of Bioinformatics.

Physical Mapping Of Dna, Dan E. Krane, Michael L. Raymer

Computer Science and Engineering Faculty Publications

Presentation prepared for BIO/CS 471: Algorithms for Bioinformatics. The lecture comprises material from the text Fundamental Concepts of Bioinformatics.

Thermomechanical Behavior Of Rotor With Rubbing, Jerzy T. Sawicki, Alberto Montilla-Bravo, Zdzislaw Gosiewski

Mechanical Engineering Faculty Publications

This article presents an analytical study of the dynamics and stability of rotors subjected to rubbing due to contact with seals, taking account of associated thermal effects. The seal interaction force acting on the shaft gives rise to a friction force, which is a source of heating and can induce so-called spiral vibrations. A mathematical model that has been developed couples the heat-conduction equation with the equations for motion of the rotor. Numerical simulations have been conducted that show the thermomechanical behavior of the rotor at various operating conditions. A procedure for analyzing the stability of multibearing rotors based on …

Web Crippling Of Cold-Formed Steel Beams At End Supports, M. W. Holesapple, Roger A. Laboube

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This investigation focused on the effects of overhang length on the web crippling capacity of cold-formed steel members. the current design recommendations in North America do not provide for an increase in web crippling capacity for end-one-flange loading when an overhang is present beyond the end support. the test specimens used for the investigation were single web C-sections and Z-sections. the current design requirements for end-one-flange web crippling capacity were found to be conservative for overhang lengths ranging from 0.5 h to 1.5 h , where h is the web depth. However, the design practice that permits the application of …

Molecular Mass And Dynamics In Pma-D₃ In The Glass Transition Region, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics through the glass transition region, by which the glassy polymer becomes rubbery, are not well understood. Free volume, thermodynamic and kinetic theories have been used to describe the phenomenon behind the glass transition and some of those theories were tested with computer simulations. Different experimental techniques, such as NMR, thermo-mechanical analysis (TMA), differential scanning calorimetry (DSC), dilatometry and dynamic mechanical analysis (DMA) have all been also used to probe this important phenomena. Deuterium (2H) NMR has been a valuable tool for the investigation of the dynamics of macromolecules. Deuteration of macromolecules at specific locations on the chains …

An Outline And Further Development Of Smith Predictor Based Methods For The Compensation Of Processes With Time Delay, Pauline Sourdille, Aidan O'Dwyer

Conference papers

An extensive literature review is presented and a new modified Smith predictor is subsequently presented.

Clinical Blood Flow Quantification With Segmented K-Space Magnetic Resonance Phase Velocity Mapping, George P. Chatzimavroudis, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando Simonetti, Paulo R. Schvartzman, Arthur E. Stillman, Richard D. White

Chemical & Biomedical Engineering Faculty Publications

To evaluate the accuracy of segmented k-space magnetic resonance phase velocity mapping (PVM) in quantifying aortic blood flow from through-plane velocity measurements.

Two segmented PVM schemes were evaluated, one with seven lines per segment (seg-7) and one with nine lines per segment (seg-9), in twenty patients with cardiovascular disease. A non-segmented (non-seg) PVM acquisition was also performed to provide the reference data.

There was agreement between the aortic flow curves acquired with segmented and non-segmented PVM. The calculated systolic and total flow volume per cycle from the seg-7 and the seg-9 scans correlated and agreed with the flow volumes from …

Water Management: Partnerships For Future Directions (Research And Testing Education Support Outreach), Mac Mckee

Reports

The UWRL is uniquely positioned to form collaborations with USU departments, other academic institutions and water centers, government, and private sector organizations involved in addressing water issues. The strong and consistent support of the State of Utah illustrates the importance of water and the creation of knowledge to manage water in Utah and the surrounding western states. The scope of projects ranges from multimillion dollar partnerships related to soil and groundwater remediation with national impacts, to small scale projects related to outreach to a specific city or county public sector audience. The UWRL mission, the strategy used to accomplish the …

Optimization And Comparison Of Broadband Monopoles, Z. N. Chen, M.Y. W. Chia, Max Ammann

Articles

The impedance and radiation properties of four broadband monopoles are compared and the parameters of a new roll monopole are optimised experimentally and numerically. The performances of the roll monopole with various numbers of roll turns are discussed and optimised numerically. The measurements and simulations show that, compared with conventional broadband monopoles, the roll monopole

Optical Switches Using Electro-Optical Effects In Liquid Crystals, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell

Articles

A simple displacement sensor based on a bent singlemode-multimode-singlemode (SMS) fiber structure is proposed and experimentally investigated. The sensor offers a wider displacement range, not limited by the risk of fiber breakage, as well as a three-fold increase in displacement sensitivity by comparison with a straight SMS structure sensor. This sensor can be interrogated by either an optical spectral analyzer (OSA) or a ratiometric interrogation system: (1) if interrogated by an OSA assuming a resolution of 1 pm, it has a sensitivity of 28.2 nm for a displacement measurement range from 0 to 280 μm; (2) if interrogated by a …

Design Criteria And Optical Characteristics Of One-Dimensional Photonic Crystals Based On Periodically Grooved Silicon, Vladimir Tolmachev, Tatiana Perova, Kevin Berwick

Articles

Photonic bandgap (PBG) regions have been calculated for periodically grooved Si structures, acting as a one-dimensional photonic crystal. The wavelength range of the PBG as a function of the ratio (D_Si/A) is presented, where D_Si is the width of the Si walls and A is the grooved silicon lattice constant. The influence of the parameter D_Si, the refractive index of the space between the Si walls and the number of structure periods, m, on the forming of PBG regions is discussed. A good correlation between the calculated and the experimentally observed …

Modified Planar Inverted-L Antenna, Jonathan Evans, Max Ammann

Conference papers

A hybrid inverted-L antenna (HIL) has been shown to reduce the physical height of a square planar monopole antenna, while retaining a relatively wide impedance bandwidth and good radiation pattern characteristics. The introduction of horizontal slots in the vertical edges of the antenna cause the surface current to meander, resulting in a decrease in the lower edge frequency of the impedance bandwidth. The impact of different sizes and arrangements of slots on impedance and radiation pattern bandwidth, gain and surface current distribution is simulated using transmission line modelling (TLM). Simulated results for impedance bandwidth are verified with measurements. With other …

Air Intake Cooling Motor Vehicle Performance Enhancement, James Brunton, David Kennedy, John D. Kelleher

Articles

This research examined the practical effects of cooling the intake air, on the combustion characteristics of a modern motor vehicle operating under simulated road conditions as well as its subsequent impact on the environment. The cooling effect was achieved by taking a typical air conditioning rig as fitted to a modern motor vehicle and incorporating it into the induction system of the car. The test vehicle used was a 1993 Renault Safrane 2.0Vi standard passenger car that was modified as part of the research to facilitate the extraction of the required test information. A series of tests were conducted using …

Indirect Evaporative Cooling Potential In Air-Water Systems In Temperate Climates, Ben Costelloe, Donal Finn

Articles

Recent developments have prompted a review of evaporative cooling technology as an effective means of cooling modern deep plan buildings. Prominent among these developments is the success of high temperature sensible cooling systems, particularly, chilled ceilings, which require a supply of cooling water at 14–18 °C. Crucial to the success of evaporative cooling technology, as a significant means of cooling in modern applications, is the ability to generate cooling water, in an indirect circuit, at a temperature which closely approaches the ambient adiabatic saturation temperature (AST) or wet bulb temperature (WBT). Recent experimental research has demonstrated that it is technically …

Environmental Planning, Steven Konkel

Books/Book chapters

No abstract provided.

Rationalising The Construction Materials Purchasing Process, Louis Gunnigan, Alan V. Hore, Trevor Orr

Conference papers

This paper is concerned with the process used in locating and removing inefficiency in the construction materials purchasing process. In the first part, a case study is presented showing the build-up of costs involved in purchasing materials. Potential for substantial savings is revealed. The second part of the paper gives a status report on a rationalisation pilot project currently being undertaken by the Construction Information Technology Alliance (CITA). This project aims to show how greater effectiveness and efficiency can be applied to the administration of the construction materials purchasing process by the application of information technology already used widely in …

Independent Subspace Analysis Using Locally Linear Embedding, Derry Fitzgerald, Eugene Coyle

Conference papers

While Independent Subspace Analysis provides a means of blindly separating sound souces from a single channel signal, it does have a number of problems. In particular the amount of information required for separation of sources varies with the signal. This is a result of the variance-based nature of Principal Component Analysis, which is used for dimensional reduction in the Independent Subspace Analysis algorithm. In an attempt to overcome this problem the use of a non-variance based dimensional reduction method, Locally Linear Embedding, is proposed. Locally Linear Embedding is a geometry based dimensional reduction technique. The use of this approach is …

Drum Transcription In The Presence Of Pitched Instruments Using Prior Subspace Analysis, Derry Fitzgerald, Robert Lawlor, Eugene Coyle

Conference papers

This paper demonstrates the use of Prior Subspace Analysis (PSA) as a method for transcribing drums in the presence of pitched instruments. PSA uses prior subspaces that represent the sources to be transcribed to overcome some of the problems associated with other subspace methods such as Independent Subspace Analysis (ISA) or sub-band ISA. The use of prior knowledge results in improved robustness for transcription purposes and enables the method to work more readily in the presence of pitched instruments than other subspace methods. The system presented in this paper attempts to extend the use of PSA to transcribe drum sounds …

Improving The Security And Flexibility Of One-Time Passwords By Signature Chains, Kemal Biçakci, Nazi̇fe Baykal

Turkish Journal of Electrical Engineering and Computer Sciences

While the classical attack of ``monitor the network and intercept the password'' can be avoided by advanced protocols like SSH, one-time passwords are still considered a viable alternative or a supplement for software authentication since they are the only ones that safeguard against attacks on insecure client machines. In this paper by using public-key techniques we present a method called signature chain alternative to Lamport's hash chain to improve security and flexibility of one-time passwords. Our proposition improves the security because first, like other public-key authentication protocols, the server and the user do not share a secret, thereby eliminating attacks …

The Economic Impacts Of Various Public-Policy Scenarios For Methane Recovery On Dairy Farms, Richard Stowell, Chris G. Henry

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

The feasibility of anaerobic digesters for dairy and swine operations in Nebraska was evaluated using EPA’s Ag Star software program Farmworks 2.0 (1997) and local values for farm energy costs, mainly electricity. Four incentive programs were considered that would subsidize anaerobic digestion. Installation of a digester system is a significant investment that is currently very difficult to justify economically to Nebraska producers based upon consideration of readily quantifiable income and expenses, regardless of farm size. Larger dairy operations looking to invest in this technology would benefit most from a tax credit and/or subsidized electricity sales, policies that relate directly to …

Roadway Related Tort Liability And Risk Management: 5th Edition, Kenneth R. Agent, Daniel S. Turner

Kentucky Transportation Center Research Report

This training material has been prepared to address the tort liability problems faced by the Kentucky Transportation Cabinet and Kentucky local governments. The manual defines the problem by reviewing the national picture of generally growing numbers of suits and escalating financial losses from suits against highway agencies.

The manual also sets out solutions, and reviews actions, which can decrease the exposure of highway agencies to these suits. This risk management concept is emphasized throughout the manual.

Test 1816: John Deere 7220 Powrquad Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Nebraska Summary 441: Fendt 714 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1820: John Deere 8220 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …