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Articles 171151 - 171180 of 198086

Full-Text Articles in Engineering

A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience, Shelli K. Starrett, Anil Pahwa, Kraig J. Olejniczak, S. D. Sudhoff, Mariesa Crow Nov 1998

A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience, Shelli K. Starrett, Anil Pahwa, Kraig J. Olejniczak, S. D. Sudhoff, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the experience of five faculty from four universities who are co-developing and team teaching courses using the world-wide web (WWW). In particular two novel power engineering courses, Flexible Control of Transmission Systems and Flexible Control of Distribuction Systems, introduce the student to the application of power electronic-based controllers, known specifically as flexible AC transmission systems (FACTS) controllers, to enhance the performance of the transmission and distribution systems in an electric power system. In order to leverage faculty expertise in the various topics included in each course, a unique partnership was formed among five faculty from the following …

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Bs News Nov 1998

Bs News

Building Services Engineering

No abstract provided.

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Productivity Improvement At A High-Tech State-Owned Industry--An Indonesian Case Study Of Employee Motivation, Adik A. Soedarsono, Susan L. Murray, Yildirim Omurtag Nov 1998

Productivity Improvement At A High-Tech State-Owned Industry--An Indonesian Case Study Of Employee Motivation, Adik A. Soedarsono, Susan L. Murray, Yildirim Omurtag

Engineering Management and Systems Engineering Faculty Research & Creative Works

The purpose of this case study was to identify the level of employee motivation at an Indonesian high-tech state-owned company. Comparisons were drawn between labor and management as well as Indonesian and Western industrial environments. The overall results provide insight into employee motivation and the potential for productivity improvement that should prove beneficial to management at state-owned and privately owned companies in Indonesia and the Pacific Rim. The study can also help Westerners appreciate culture differences and productivity challenges in this developing country.

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Case Study Comparisons Of Standard And Energy Efficient Polyphase Induction Motors Subjected To Unbalances Phase Voltages, Brian L. Bidwell Nov 1998

Case Study Comparisons Of Standard And Energy Efficient Polyphase Induction Motors Subjected To Unbalances Phase Voltages, Brian L. Bidwell

Masters Theses and Doctoral Dissertations

This study investigates the behaviors and economics of standard and energy efficient polyphase induction motors under unbalanced phase voltage conditions ofup to 5 percent. Motors sizes of 25, 50, 100,150,200, 250 and 300 hp are used in this investigation. Computer simulations are used to study the efficiencies, power losses and economics of motor behavior when unbalanced phase voltage system conditions exist. Previous polyphase induction motor studies simulated unbalanced phase voltage conditions by assuming a high impedance fault at the motor terminals. In this study, a method is used to simulate unbalanced phase voltage conditions by varying the phase voltage at …

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Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas Nov 1998

Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

The data collected by ALEPH at LEP at centre-of-mass energies ranging from 181 to 184 GeV, corresponding to an integrated luminosity of 57 pb−1, are analysed to search for pair-produced neutral Higgs bosons h and A, in the bb̄bb̄ and τ+τ−bb̄ final states. Two events are found in the data with 2.5 expected from standard model processes. When combined with the lower energy data collected by ALEPH and with earlier reported searches for associated hZ production, these analyses are interpreted in the context of the minimal supersymmetric extension of the standard model (MSSM). For standard choices of MSSM parameter sets, …

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Development Of A Discrete Ordinates Code System For Unstructured Meshes Of Tetrahedral Cells, With Serial And Parallel Implementations, Rodney L. Miller Nov 1998

Development Of A Discrete Ordinates Code System For Unstructured Meshes Of Tetrahedral Cells, With Serial And Parallel Implementations, Rodney L. Miller

Theses and Dissertations

A numerically stable, accurate, and robust form of the exponential characteristic (EC) method, used to solve the time-independent linearized Boltzmann Transport Equation, is derived using direct affine coordinate transformations on unstructured meshes of tetrahedra. This quadrature, as well as the linear characteristic (LC) spatial quadrature, is implemented in our transport code, called TETRAN. This code solves multi-group neutral particle transport problems with anisotropic scattering and was parallelized using High Performance Fortran and angular domain decomposition. A new, parallel algorithm for updating the scattering source is introduced. The EC source and inflow flux coefficients are efficiently evaluated using Broyden's rootsolver, started …

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Emerald: Where We Are And Where We Are Going, Freddy Pranajaya, Bryan Palmintier Oct 1998

Emerald: Where We Are And Where We Are Going, Freddy Pranajaya, Bryan Palmintier

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Freddy Pranajaya and Bryan Palmintier titled "EMERALD: Where We Are and Where We Are Going" from October 29, 1998.

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Tractor Museum Committee Minutes October 20, 1998, Tractor Museum Oct 1998

Tractor Museum Committee Minutes October 20, 1998, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Treasurer's Report State Fair Report Accident Insurance

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Deriving Of Single Intensive Picosecond Optical Pulses From A High-Power Gain-Switched Laser Diode By Spectral Filtering, S. N. Vainshtein, Grigory Simin, J. T. Kostamovaara Oct 1998

Deriving Of Single Intensive Picosecond Optical Pulses From A High-Power Gain-Switched Laser Diode By Spectral Filtering, S. N. Vainshtein, Grigory Simin, J. T. Kostamovaara

Faculty Publications

Single 25 ps/16 W optical pulses were achieved by spectral filtering from a multiheterostructure gain-switched laser diode with its quasisteady-state modes suppressed by a factor of 103 as compared with the peak power. A significant transient spectrum broadening makes this possible provided that a very high dI/dt rate of the pumping current pulse is used. A simple numerical model is suggested which describes adequately both the spectral and transient features of the observed phenomenon. It follows from the model that single picosecond optical pulses can be obtained from any type of high power semiconductor laser.

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A Simplified Model For Distortional Buckling Of Channels And Zees In Flexure, Duane S. Ellifritt, Robert L. Glover, Jonathan D. Hren Oct 1998

A Simplified Model For Distortional Buckling Of Channels And Zees In Flexure, Duane S. Ellifritt, Robert L. Glover, Jonathan D. Hren

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

Certain cold-formed sections like channels and zees, when subjected to bending in the plane of the web, often fail in laboratory tests at a load less than that predicted by standard specification equations. The mode of failure is an upward movement of the compression flange and lip relative to the web, which may remain fairly plane. When bends which were right angles change dramatically under load, the section changes shape, or distorts, resulting in a reduction of the section stiffness followed by buckling of the flange. Such a failure is referred to as "distortional buckling". An analytical solution to the …

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Buckling Mode Interaction In Cold-Formed Steel Columns And Beams, C. Jiang, Viorel Ungureanu, J. Michael Davies Oct 1998

Buckling Mode Interaction In Cold-Formed Steel Columns And Beams, C. Jiang, Viorel Ungureanu, J. Michael Davies

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

The buckling behaviour of cold-formed steel columns and beams is far from simple. The three generic forms of buckling, namely local buckling, distortional buckling and overall buckling, generally have different wavelengths and are usually restricted to different span ranges. However, there is also the possibility of interaction among these buckling modes at a certain span length. Thus, local plate buckling and distortional buckling may occur together with lateral-torsional buckling in such a way that they all have an influence on the ultimate load carrying capacity of a member. The influence of local buckling is taken into consideration in design codes …

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Distortional Buckling Formulae For Thin Walled Channel And Z-Sections With Return Lips, John T. Merrick, Gregory J. Hancock, M. R. Bamach Oct 1998

Distortional Buckling Formulae For Thin Walled Channel And Z-Sections With Return Lips, John T. Merrick, Gregory J. Hancock, M. R. Bamach

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

Cold-formed Channel- and Z-sections subject to both flexure and torsion may undergo distortional buckling where the flange and lip rotate about the flange/web junction. This mode of failure is prevalent in purlin sections when lateral deformation of the section is prevented and when the sections are manufactured from high strength steel. In an attempt to prevent distortional buckling, some manufacturers have added additional return lips to the flange lips to produce complex edge stiffeners. The Australian/New Zealand Standard for Cold-Formed Steel Structures includes design rules for determining the distortional buckling strength of cold-formed beam and column sections. These design rules …

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Laterally Braced Cold-Formed Steel Flexural Members With Edge Stiffened Flanges, Benjamin W. Schafer, Teoman Pekoz Oct 1998

Laterally Braced Cold-Formed Steel Flexural Members With Edge Stiffened Flanges, Benjamin W. Schafer, Teoman Pekoz

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

The moment capacity of a laterally braced cold-formed steel flexural member with edge stiffened flanges (e.g., a channel or zee section) may be adversely affected by local or distortional buckling. Traditional design methods recognize the need to explicitly account for local buckling, but not distortional buckling. Experimental data and numerical analyses suggest that proper strength prediction of laterally braced cold-formed steel flexural members requires explicit treatment of distortional buckling. New procedures for hand prediction of the buckling stress in the local and distortional mode are presented. Numerical investigations are employed to highlight post-buckling behavior unique to the distortional mode. A …

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Behaviour Of Thin G550 Sheet Steel Bolted Connections, Colin A. Rogers, Gregory J. Hancock Oct 1998

Behaviour Of Thin G550 Sheet Steel Bolted Connections, Colin A. Rogers, Gregory J. Hancock

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

This paper provides a summary of results detailing the behaviour of bolted connections tested in shear, which were composed of 0.42 mm G550, 0.60 mm G550 and 0.60 mm G300 sheet steels (to the 1993 Australian Standard AS 1397). Recommendations concerning the adequacy of current design standards with respect to the design of thin sheet steel bolted connections are made, along with the calibration of applicable limit states resistance equations for the three observed modes of failure; end pull-out, bearing, and net section fracture.

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Factors Influencing The Strength Of Mechanical Clinching, Remo Pedreschi, Braj Sinha, Russell Davies, Rory Lennon Oct 1998

Factors Influencing The Strength Of Mechanical Clinching, Remo Pedreschi, Braj Sinha, Russell Davies, Rory Lennon

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

The influence of material strength and thickness, direction of load, multi-layer connections and dis-similar thicknesses of steel on the strength of mechanical clinching is considered.. Expressions to predict the strength of mechanical clinching are presented.

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Lateral Load Strength Of Screw Connections In 29ga Metal, G. A. Anderson, V. C. Kelley Oct 1998

Lateral Load Strength Of Screw Connections In 29ga Metal, G. A. Anderson, V. C. Kelley

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

The results of 300 tests on screwed connections in shear are presented. The load capacity of screws in a row is shown to be additive and screws placed in narrow ribs of 29ga steel have the same strength as screws placed in flat sheets. The AISI equation for tilting strength of screw connections under predicts the strength of the screw connections tested. A regression equation is developed for tilting and compared to the AISI tilting equation and a third party test data. The regression equation is more accurate but less precise than the AISI equation.

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Spacing Of Connections In Compression Flanges Of Built-Up Cold-Formed Steel Beams, Roger A. Laboube, Wei-Wen Yu, Michael L. Jones Oct 1998

Spacing Of Connections In Compression Flanges Of Built-Up Cold-Formed Steel Beams, Roger A. Laboube, Wei-Wen Yu, Michael L. Jones

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

Built-up cold-formed steel sections may offer greater economy in building construction. Typical built-up sections are cellular decks or door and window header beams. A research project was initiated to determine if the current spacing criteria outlined in Section D1.2 of the AISI Specification accurately predicted the capacity of built-up sections with the cover plate in compression. This study showed that criteria No.2 of the AISI Design Specification spacing criteria is restrictive when applied to built-up cross sections in bending. All test sections continued to carry additional load after the cover plate buckled. The tests showed that as the spacing of …

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A Cost Based Approach To Design Of Residential Steel Roof Systems, B. Mobasher, S-Y Chen, C. Young, S. D. Rajan Oct 1998

A Cost Based Approach To Design Of Residential Steel Roof Systems, B. Mobasher, S-Y Chen, C. Young, S. D. Rajan

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

A comprehensive system for the design of residential steel roof truss systems is presented. The research involved three distinct stages. In the first stage, components of the truss systems were tested in order to determine their member properties subjected to axial force and bending moments. Finite element simulations of these tests were carried out to further verify the, calculations obtained using the AISI-LRFD code guidelines. The AlSI-LRFD code based design curves were used for the actual design, while the laboratory experiments and the finite element results provided additional checks and verification of the AlSI values. The second stage of the …

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Compressional Behaviour Of Stainless Steel Short Struts, M. Macdonald, J. Rhodes, G. T. Taylor Oct 1998

Compressional Behaviour Of Stainless Steel Short Struts, M. Macdonald, J. Rhodes, G. T. Taylor

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

The effects of cold forming on both carbon steel and stainless steel structural members has been the subject of extensive research since the early 1940's. Design code specifications for carbon steel members have been published in many countries around the world, including BS 5950, Part 5 in the UK (1) the AlSI Specification in the USA (2), and the new Eurocode 3, Part 1.3 (3). For stainless steel members there are fewer design code specifications available, and those that are available, which include the ANSI/ASCE in the USA (4) and the new Eurocode 3, Part 1.4 (5), do not give …

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The Effect Of Cold Forming On Type 3cr12 Square Tubes, Rudolph Laubscher Oct 1998

The Effect Of Cold Forming On Type 3cr12 Square Tubes, Rudolph Laubscher

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

A non linear finite element simulation is conducted which completely simulates the forming of the tube from flat virgin plate to its final shape. The predicted residual stresses and amount of cold forming in the tube sides and comers are then compared to actual experimental data from cold formed tubes where the initial material properties and the material properties after the cold forming process are known. This illustrates the usefulness of the non linear finite element method in predicting how the material properties change during cold forming and gives a useful insight in what the actual condition of the material …

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The Local Buckling Strength Of Partially Stiffened Type 3cr12 Stainless Steel Compression Elements In Beam Flanges, G. J. Van Den Berg Oct 1998

The Local Buckling Strength Of Partially Stiffened Type 3cr12 Stainless Steel Compression Elements In Beam Flanges, G. J. Van Den Berg

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

In this study the effect of the non-linear behaviour of stainless steels on the local buckling strength of partially stiffened compression elements in beam flanges is studied. The steel under investigation is Type 3CR12 stainless steel. Lipped channels were placed back to back to form a doubly symmetric lipped I-section. The different pIasticity reduction factors suggested in the ASCE3 and South African13 stainless steel design specification for stiffened and unstiffened compression elements are used to compare experimental results with theoretical predictions. It is concluded that the ASCE3 and South African13 stainless steel design specifications overestimate the local buckling stress in …

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A Non Linear Design Model For Continuous Multi-Span Light Gauge Sheeting And Members, Leopold K. Sokol Oct 1998

A Non Linear Design Model For Continuous Multi-Span Light Gauge Sheeting And Members, Leopold K. Sokol

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

The calculation of profiled sheeting and members by using the post-critical stage in which a plastic hinge is originated at the internal support is possible provided that the relationships between the support moment, reaction and hinge rotation are known. There are two alternative procedures of testing for obtaining these data: double-span test or internal support test. In the second one, instead of a global behaviour, only the local relationships between the three above characteristics are determined. When calculating with the model proposed in Eurocode 3, Part 1.3, the above two different test procedures do not lead to close enough results. …

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Analysis Of Hat Sections With Multiple Intermediate Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster Oct 1998

Analysis Of Hat Sections With Multiple Intermediate Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster

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

This paper is the second paper by the authors on the subject of the behavior of cold formed steel hat sections in bending with multiple intermediate longitudinal stiffeners. The first paper, also contained in these Proceedings, deals with the test results only (Acharya and Schuster, 1998). Presented in this paper is the analysis associated with the test program that was conducted at the University of Waterloo. The main objective was to develop a consistently accurate and practical method of predicting the ultimate bending strength of sections that fail in overall plate buckling. Recent testing carried out by previous researchers indicates …

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Bending Tests Of Hat Sections With Multiple Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster Oct 1998

Bending Tests Of Hat Sections With Multiple Longitudinal Stiffeners, V. V. Acharya, R. M. Schuster

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

This paper is the first in a series of articles that report findings of the authors investigation into the behavior of cold formed steel hat sections in bending with multiple intermediate longitudinal stiffeners. Presented in this paper is the test program that was carried out at the University of Waterloo as part of a two year research program. It is known that sections with multiple intermediate stiffeners can fail either in a local sub-element buckling mode, or alternatively, can experience an overall plate buckling mode of failure. Although both failure modes were examined, the main objective was to develop a …

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Direct Strength Prediction Of Cold-Formed Steel Members Using Numerical Elastic Buckling Solutions, Benjamin W. Schafer, Teoman Pekoz Oct 1998

Direct Strength Prediction Of Cold-Formed Steel Members Using Numerical Elastic Buckling Solutions, Benjamin W. Schafer, Teoman Pekoz

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

Current design of cold-formed steel members is unduly complicated, Part of this complication arises from the need to perform elastic buckling calculations by hand. Also, complications occur in determining the effective width and resulting effective properties of members. Further, as cross-sections become more optimized (e.g., through the introduction of longitudinal stiffeners) both the elastic buckling and effective width calculations become markedly more complex. In order to investigate alternatives to current design a large amount of experimental data on flexural members of varying geometry is collected. The use of numerical elastic buckling solutions for the entire member, is investigated as an …

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Shear Plus Bending In Lapped Z-Purlins, Keith Almoney, Thomas M. Murray Oct 1998

Shear Plus Bending In Lapped Z-Purlins, Keith Almoney, Thomas M. Murray

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

Six two purlin line, three span continuous Z-purlin tests were conducted to show that combined shear plus bending is a possible failure mode immediately outside the lapped portion of the purlin lines. AISI Specification provisions predicted that combined shear plus bending was the controlling limit state. Strain gage data showed that local buckling occurred immediately outside of the lapped portion of the purlins lines prior to failure which caused moment to redistribute to the positive moment region. It is concluded that shear plus bending is a possible controlling limit state for continuous lapped purlins.

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Web Crippling Behaviour Of Cold-Formed Unlipped Channels, Ben Young, Gregory J. Hancock Oct 1998

Web Crippling Behaviour Of Cold-Formed Unlipped Channels, Ben Young, Gregory J. Hancock

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

An experimental investigation of cold-formed unlipped channels subject to web crippling is described. The tests were carried out under four loading conditions according to the AISI Specification, namely End-One-Flange (EOF), Interior-One-Flange (IOF), End-Two-Flange (ETF), and Interior-Two-Flange (ITF) loading. The concentrated load or reaction forces were applied by means of bearing plates which acted across the full flange widths of the channels. The web crippling test results are compared with the American Iron and Steel Institute (AISI 1996) Specification and the Australian/New Zealand Standard (AS/NZS 4600-1996) for cold-formed steel structures. The design web crippling strength predictions given by the specifications have …

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Web Crippling Of Single Web Cold Formed Steel Members Subjected To End One-Flange Loading, R. R. Gerges, R. M. Schuster Oct 1998

Web Crippling Of Single Web Cold Formed Steel Members Subjected To End One-Flange Loading, R. R. Gerges, R. M. Schuster

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

Results of an extensive experimental investigation of the web crippling behavior of cold formed steel C-sections are presented. This study was devoted to the End One Flange, EOF, loading case, with particular emphasis on large inside bend radius to thickness ratios, (R = ri/t). Seventy-two C-sections with R values ranging between five and 10 were tested at the University of Waterloo. Comparing the experimental results with predictions using the current North American Cold Formed Steel Design Standards, considerable underestimation was observed. Using the same model of the design expression currently used in the Canadian Standard (S136-94), and including 164 test …

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Web Crippling Strength Of Members Using High-Strength Steels, Shaojie Wu, Wei-Wen Yu, Roger A. Laboube Oct 1998

Web Crippling Strength Of Members Using High-Strength Steels, Shaojie Wu, Wei-Wen Yu, Roger A. Laboube

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

A total of 148 web crippling tests were conducted using high-strength, low-ductility Structural Grade 80 of ASTM A653 steel (former ASTM A446 Grade E steel) and tests results were evaluated along with additional 114 web crippling tests which were reported in 1986 as part of a project on Design of Automotive Structural Components Using High-Strength Sheet Steels. Four loading conditions, namely End-One-Flange (EOF),lnterior-One-Flange (IOF), End-Two-Flange (ETF), and Interior-Two-Flange (ITF) conditions, were considered in the web crippling tests. Test results indicate that the tested ultimate loads for the four loading conditions were higher than the predicted loads using the AISI Specifications …

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Behaviour Of Locally Buckled Singly Symmetric Columns, Ben Young, Kim J. R. Rasmussen Oct 1998

Behaviour Of Locally Buckled Singly Symmetric Columns, Ben Young, Kim J. R. Rasmussen

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

An experimental investigation into the behaviour of locally buckled cold-formed plain and lipped channel columns compressed between fixed and pinned ends is described in this paper. It is shown experimentally that local buckling does not induce overall bending of fixed-ended singly symmetric columns, as it does of pin-ended singly symmetric columns. Consequently, local buckling has fundamentally different effects on the behaviour of fixed-ended and pin-ended singly symmetric columns. In order to demonstrate this result experimentally, a series of tests was performed on plain and lipped channels brake-pressed from high strength structural steel sheets. The different effects of local buckling on …

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