Engineering Commons^™

Faulty Behavior Of Storage Elements And Its Effects On Sequential Circuits, Waleed K. Al-Assadi, Y. K. Malaiya, A. P. Jayasumana

Electrical and Computer Engineering Faculty Research & Creative Works

It is often assumed that the faults in storage elements (SEs) can be modeled as output/input stuck-at faults of the element. They are implicitly considered equivalent to the stuck-at faults in the combinational logic surrounding the SE cells. Transistor-level faults in common SEs are examined here. A more accurate higher level fault model for elementary SEs that better represents the physical failures is presented. It is shown that a minimal (stuck-at) model may be adequate if only modest fault coverage is desired. The enhanced model includes some common fault behaviors of SEs that are not covered by the minimal fault …

Lattice Boltzmann Thermohydrodynamics, F. J. Alexander, S. Chen, J. D. Sterling

Business and Information Technology Faculty Research & Creative Works

We introduce a lattice Boltzmann computational scheme capable of modeling thermohydrodynamic flows of monatomic gases. The parallel nature of this approach provides a numerically efficient alternative to traditional methods of computational fluid dynamics. The scheme uses a small number of discrete velocity states and a linear, single-time relaxation collision operator. Numerical simulations in two dimensions agree well with exact solutions for adiabatic sound propagation and Couette flow with heat transfer. © 1993 The American Physical Society.

Decision-Support Tools For Transferring Am/Fm/Gis To Small Communities, Steven W. Mccrary, Colin Othniel Benjamin, Peter J. Schmidt

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper examines several decision-support tools for transferring AM/FM/GIS technology to small communities. The term Computer-Assisted Spatial Information Systems (CASIS) provides a basis for a systematic categorization and definition of AM/FM/GIS systems that will serve to enhance small communities' understanding of these technologies for future decisions. The acronym CASIS includes such areas as database-management systems, automated mapping/facilities management/geographic information systems (AM/FM/GIS), and computer-aided drafting (CAD). Further, this paper reports the highlights of a survey that assesses the theory-practice gap in AM/FM/GIS usage among very small local government agencies. The survey uncovered an existing theory-practice gap: A, slow rate of system …

Modeling Of Intra-Cell Defects In Cmos Sram, Waleed K. Al-Assadi, Y. K. Malaiya, A. P. Jayasumana

Electrical and Computer Engineering Faculty Research & Creative Works

The effect of defects within a single cell of a static random access memory (SRAM) is examined. All major types of faults, including bridging, transistor stuck-open and stuck-on, are examined. A significant fraction of all faults cause high IDDQ values to be observed. Faults leading to inter-cell coupling are identified.

Automatic Color Segmentation Algorithms-With Application To Skin Tumor Feature Identification, Scott E. Umbaugh, Randy Hays Moss, William V. Stoecker, G. A. Hance

Electrical and Computer Engineering Faculty Research & Creative Works

Two color-image segmentation methods are described. The first is based on a spherical coordinate transform of original RGB data. The second is based on a mathematically optimal transform, the principal components transform (also known as eigenvector, discrete Karhunen-Loeve, or Hotelling transform). These algorithms are applied to the extraction from skin tumor images of various features such as tumor border, crust, hair scale, shiny areas, and ulcer. The results of this research will be used in the development of a computer vision system that will serve as the visual front-end of a medical expert system to automate visual feature identification for …

Detection Of Skin Tumor Boundaries In Color Images, Fikret Erçal, M. Moganti, William V. Stoecker, Randy Hays Moss

Computer Science Faculty Research & Creative Works

A simple and yet effective method for finding the borders of tumors is presented as an initial step towards the diagnosis of skin tumors from their color images. The method makes use of an adaptive color metric from the red, green, and blue planes that contains information for discriminating the tumor from the background. Using this suitable coordinate transformation, the image is segmented. The tumor portion is then extracted from the segmented image and borders are drawn. Experimental results that verify the effectiveness of this approach are given

Galvanic Stripping Of Fe⁺³ And Pb⁺² Ions And Dissolution Of Metallic Fe, Zn, Pb And Cd Using Di(2-Ethylhexyl)Phosphoric Acid, Luis Miguel Chia Aquije

Doctoral Dissertations

"Two systems were evaluated using the principles of the galvanic stripping process. One of them, the removal of Pb⁺² ions from di-2(ethylhexyl) phosphoric acid (D2EHPA) was performed using metallic zinc. The other, the removal of Fe⁺³ ions from D2EHPA used metallic iron as reductant and was performed simultaneously with the organic phase using a slightly acidic aqueous solution of hydrochloric acid. In addition, the dissolution of metallic zinc, iron, lead, and cadmium in D2EHPA was studied in order to better understand the anodic step in the mechanism of the galvanic stripping process.

Increased temperature was found to dramatically …

Inclined-Field Structure, Morphology, And Pinning Of The Vortex Lattice In Microtwinned Yba2cu3o7, B. Keimer, F. Doǧan, I. A. Aksay, R. W. Erwin, J. W. Lynn, M. Sarikaya

Materials Science and Engineering Faculty Research & Creative Works

A detailed small-angle neutron scattering study of the vortex lattice in a single crystal of YBa2Cu3O7 was made for a field of 0.5 tesla inclined at angles between 0 and 80 degrees to the crystalline c axis. The vortex lattice is triangular for all angles, and for angles less than or equal to 70 degrees its orientation adjusts itself to maximize the pinning energy to densely and highly regularly spaced twin planes. These observations have important implications for the microscopic flux-pinning mechanism, and hence for the critical current achievable in YBa2Cu3O7. For large angles (about 80 degrees) the vortex lattice …

A Model Of Electronic Warfare Systems Acquisition And Engineering For Saudi Arabia, Negaa M. Albegami

Doctoral Dissertations

"A major activity within the systems engineering process is the requirements definition and analysis phase. In technical systems, planning this phase looks too technical for top management and too broad for the engineers specialized in narrow technical fields. This categorization (too technical/too broad) represents a gap between top management and specialized engineering. In Saudi Arabia, such a gap is believed to be very wide.

The main objective of this research is to find a way to narrow this gap between management and engineering when planning government systems, especially in electronic warfare (EW) systems. A solution in this effort is to …

Design Of Automotive Structural Components Using High Strength Sheet Steels Influence Of Strain Rate On The Mechanical Properties Of Sheet Steels And Structural Performance Of Cold-Formed Steel Members, Chi-Ling Pan, Wei-Wen Yu

CCFSS Library (1939 - present)

The current design criteria for effective design width being used in the AISI Automotive Steel Design Manual 1 for the design of cold-formed steel members are based on tests under static loading condition. The primary objective of this investigation was to study the validity of these effective design width formulas for members subjected to dynamic loads. This report presents a detailed description of an experimental study. Selected steels with nominal yield strengths ranging from 25 ksi to 100 ksi were uniaxially tested under different strain rates. In order to study the structural behavior and strength of cold-formed steel members having …

Hands-On Structural Engineering Experiences With The "Anex" Mini-Laboratory, Richard A. Behr, Colin Othniel Benjamin, Azam A. Mirza

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The ANEX facility has been developed to allow nearly real-time comparisons of analysis results with experimental data gathered on small-scale structural models. ANEX has been used successfully for in-class demonstrations, student-designed experiments, and comprehensive design/build competitions in an introductory structural analysis course at the University of Missouri-Rolla. An expert system is now being developed to guide ANEX users and to act as a trouble-shooter and advisor in the event that analytical and experimental results do not correlate acceptably well. ANEX, using only simple, small-scale model structures, is able to enrich structural engineering instruction by introducing students to the sophisticated capabilities …

Electrochemical Evaluation Of The Adherence Of Zinc To Aluminum Cathodes, Jang Sop Han, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Excess fluoride ions in zinc electrolyte are known to cause problems with the removal of electrowon zinc from aluminum blanks. The mechanisms responsible for this undesirable adherence were studied. Acid zinc sulfate electrolyte similar to that employed in zinc electrowinning was used. Using electrolyte containing various fluoride ion concentrations, the initial nucleation and growth morphology of zinc and the aluminum electrode surface were examined using scanning electron microscopy. Electrochemical tests were also carried out in various solutions to obtain a better understanding of the polarization behavior of the system. © 1992.

Structural Ceramic Incorporating Boron Carbide Whiskers For The Strengthening Thereof, P. D. Ownby, J. Liu

Materials Science and Engineering Faculty Research & Creative Works

Ceramic composites, and in particular structural ceramic composites, have enhanced strength, toughness and abrasion resistance due to the presence of up to about 40 volume percent of relatively large boron carbide whiskers. Although whiskers of various sizes were studied, those of particular interest are whiskers having an average diameter greater than about 3 micrometers, and particularly about 5 to about 8 micrometers, with an average aspect ratio of about 50. Due to the larger size, which had been predicted to be detrimental, there is less respiratory health risk when using these whiskers in the manufacturing of thse improved ceramic composites. …

Investigation Of Strontium-Doped La(Cr, Mn)O3 For Solid Oxide Fuel Cells, Rasit Koc, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The (La, Sr) (Cr, Mn)O₃ system was investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells. Sintering studies were done in air at temperatures below 1500°C. Significant improvements in densification were observed with substitution of 50 mol% Mn for chromium and a density of 95% theoretical was achieved with the substitution of 70 mol% Mn for chromium in the La(Cr, Mn)O₃ system. Electrical conductivity (d.c.) measurements were made as a function of temperature and oxygen activity. At 1000°C and 1 atm oxygen, the electrical conductivity ranged from 2.2-20 S cm^{-1 …}

Photoluminescence And Raman Studies Of Cds Films Grown By Metal-Organic Chemical Vapor Deposition On Si{111} Substrates, Alok K. Berry, P. M. Amirtharaj, Jing Tong Du, Jack L. Boone, Don D. Martin

Electrical and Computer Engineering Faculty Research & Creative Works

CdS epitaxial films grown using metal-organic chemical vapor deposition on Si{111} substrates at growth temperatures ranging from 270 to 325 °C have been characterized using photoluminescence and Raman spectroscopy. Out of all the samples the best optical behavior is obtained from that grown at the lowest temperature. Samples grown at the lowest temperature exhibited increased intensity of the bound excitonic peaks and reduced emission at the defect-related luminescence region. The Raman spectra were compatible with the film surface being normal to the c axis, indicating a preferred growth orientation. © 1992.

Bending Strength Of Beams With Non-Linear Analysis, Pekka Salmi, Asko Talja

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Bending strengths of open cross-section beams cold-formed from high-strength steel (HSS) are determined with non-linear analysis. Two kinds of beams are studied. The short beams are for examining the bending resistance of cross-sections and the long beams for studing the lateral buckling of open sections. The beams are modelled with shell elements and non-linear FEM analyses are carried out to predict the strengths of the models. Both material and geometrical non-linearities are included in the analyses. The results are compared with experimental results.

Profiled Sheet Behaviour Under Concentrated Load, Mohsen M. Salaheldin, Lweis C. Schmidt

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The behaviour of profiled sheets under concentrated static load is discussed. The effect of aspect ratio and the depth of the sheet on the redistribution of stresses is investigated. The stress concentration caused by the concentrated load can lead to an anomalous pattern of behaviour, where local plastic failure occurs at lower loads in shorter spans rather than in longer spans.

Observations And Comments Pertaining To Can/Csa-S136-M89, Aaron S. Dinovitzer, Majid Sohrabpour, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Contained in this paper are the results of two separate studies, namely, 1) partially stiffened compressive elements of both edge and single intermediate stiffened flanges and 2) deflection determination of multi-web deck profiles. Both of these studies were based on the Canadian cold formed steel design standard (CAN/CSA-S 136-M89), with the results also applicable to the AISI specification. In the case of partially stiffened compressive elements, discontinuities in effective width estimates for sections with similar flanges and stiffeners were observed, resulting from a sudden change in the behavioural states. Recommendations are presented to rectify this discontinuity and at the same …

New Asce Standards For Cold-Formed Steel Deck Slabs, Max L. Porter

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper presents highlights of the newly approved and printed ASCE Standard on the design and construction of composite floor deck slabs utilizing cold-formed steel. In 1992 four documents are being published including the following: • "Standard for the Structural Design of Composite Slabs"--ASCE3-92, • "Standard Practice for Construction and Inspection of Composite Slabs"-ASCE9-92, and • A separate commentary on each of the two above Standards. These above four documents stem from a previously published ASCE Standard entitled "Specifications for the Design and Construction of Composite Slabs" and the associated commentary thereon. The Steel Deck with Concrete Committee of the …

Calibration Of A Bending Model For Cold-Formed Sections, A. De Martino, A. Ghersi, Frederico M. Mazzolani

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The calibration procedure of a numerical model based on the simulation of the moment-curvature relation for cold-formed steel beams is presented. The results of bending tests on beams with double-channel cross-section are used to assess the proper values to the parameters which quantify the model.

Tests Of Profiled Steel Decks With V-Stiffeners, E. S. Bernard, Russell Q. Bridge, Gregory J. Hancock

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The size and position of intermediate stiffeners in the compression flanges of thin-walled profiled steel decks exerts a strong influence on the dominant buckling mode of the flange. The ability of the deck to provide both high load carrying capacity before the onset of elastic buckling and a high ultimate load capacity may therefore be affected. A programme of tests to determine the effectiveness of intermediate stiffeners in controlling buckling modes has been undertaken. A series of specimens were loaded in pure bending resulting in various buckling waveforms prior to ultimate failure through a plastic collapse mechanism. All specimens were …

Unstiffened Elements - Some Interesting Features, J. Rhodes

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The behaviour of members composed of unstiffened elements is examined with reference to three different sets of test results, on angle section struts, Tee section beams and shallow Vee section beams. The test results are explained on the basis of fairly simple analysis, and the variations of the behaviour from that predicted by modem design codes is discussed.

Behavior Of Arc Spot Weld Connections In Tension, Roger A. Laboube, Wei-Wen Yu

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A comprehensive experimental study of the tension strength of arc spot weld connections, that affix a cold-formed steel roof deck to its support member, was conducted. Based on the experimental results obtained from over 260 connection tests, equations have been developed that predict the tension capacity of an arc spot weld connection. These equations are easily applied, and lend themselves to use by structural designers.

Activities Of The Center For Cold-Formed Steel Structures, Wei-Wen Yu, Roger A. Laboube

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The Center for Cold-Formed Steel Structures was established at the University of Missouri-Rolla in May 1990 under the sponsorship of the American Iron and Steel Institute and the University of Missouri-Rolla. This paper summarizes the activities performed at the Center during the past two years.

Education In Cold-Formed Steel Structures - Lifelong Learning, Albert L. Johnson

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

What is the system we're dealing with? Who's in the audience? What is the information we need? How do we package it? How is it delivered? How do we know if we've done a good job?

Experimental Investigations Of I-Beams, Shang-Jian Chen, Shan-Feng Fang

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

I - beams made of cold - formed thin - walled channels, back to back, can be connected by resistance spot welding or arc-welding. Both stability and ultimate strength of these beams are different for welding method. The stability can be increased provided several battens are attached on the open sections of these beams.

Flexural Capacity Of Discretely Braced C'S And Z'S, Thomas Sputo, Jack Haynes, Duane S. Ellifritt

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The American Iron and Steel Institute's Specification for the Design of Cold-Formed Steel Structural Members (1) presently requires that channel and zee flexural members, when not attached to sheathing, be braced against twist and lateral translation at the quarter-points of the span (Section D3.2.2). This provision first appeared in the Second Edition of the Specification in 1956, and has been there through all succeeding editions up through the 1989 Addendum. The newest formula for lateral buckling (part (a) of C3.1.2) is a more exact procedure for calculating lateral torsional buckling of a doubly, singly, or point symmetrical section than was …

Lateral Buckling Of Singly Symmetric Beams, Teoman Pekoz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

General solutions for the elastic lateral buckling moment of singly symmetric sections are studied. The studies include the effect of the location of the load on the section as well as the effect of moment gradients on the lateral buckling moment. Design provisions are outlined for the case of moment gradients.

Tests Of Continuous Purlins Under Downwards Loading, Michael Celeban, Chris Healy, Gregory J. Hancock

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The paper describes a test program on purlin-sheeting systems for which the sheeting was screw fastened to the purlins. The test program simulates downwards loading. Z-section purlins were tested in three span continuous lapped configurations. The test purlins were supported by a range of bridging (bracing) members ranging from no bracing to one brace per span. The test results are compared with the design values computed using the Australian Cold-Formed Steel Structures Standard (AS1538-1988). The Australian Standard design is based on a flexural-torsional buckling analysis which may include the restraint from attached sheeting.

The Buckling Behaviour Of Hollow Flange Beams, Mahen Mahendran, T. J. Heidt

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A new cold formed structural section known as the hollow flange beam is currently under development in Australia. This section will have many applications, particularly in portal frame buildings. This paper discusses the lateral distortional buckling behaviour of the hollow flange beam.