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Articles 9991 - 10020 of 13031

Full-Text Articles in Engineering

Spatial Buckling Behavior Of High-Rise Rack Frames, Lip H. Teh, Gregory J. Hancock, Murray J. Clarke Oct 2000

Spatial Buckling Behavior Of High-Rise Rack Frames, Lip H. Teh, Gregory J. Hancock, Murray J. Clarke

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

The paper investigates the global elastic buckling behavior of a high-rise adjustable pallet rack frame composed of thin-walled open sections. It is concluded that the simple element used in many commercial programs for 3D frame analysis is not sufficiently refined for accurate linear buckling analyses of high-rise rack frames.

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Design Of Cold-Formed Steel Plain Channels, Fang Yiu, Teoman Pekoz Oct 2000

Design Of Cold-Formed Steel Plain Channels, Fang Yiu, Teoman Pekoz

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

This paper gives an overview of the design procedures formulated for plain channels. These formulations are based on experimental and finite element studies. The scope of the work covers laterally braced beams, columns and beam-columns of cross-sections in the range of practical applications by the industry. The recommendations treat members that are made up of elements that may be in the post-buckling or post yielding range.

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Eccentrically Loaded Bolted Connections For Type 304 And 3cr12 Stainless Steel Lipped Channels, P. Van Tonder, Q. C. Oliphant, G. J. Van Den Berg Oct 2000

Eccentrically Loaded Bolted Connections For Type 304 And 3cr12 Stainless Steel Lipped Channels, P. Van Tonder, Q. C. Oliphant, G. J. Van Den Berg

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

In this paper the results of a study on eccentrically loaded bolted connections in lipped channels are presented. The steels chosen for this study are AISI Type 304 and Type 3CR12 stainless steel. It is concluded in this investigation that an acceptable prediction of the strength of eccentrically loaded bolted connections of stainless steel lipped channels may be obtained through the combination between the eccentric loaded equation and the normal bolted connection equations for stainless steel.

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Optimum Design Of Cold Formed Steel Residential Roof Trusses, L. Xu, H. Min Oct 2000

Optimum Design Of Cold Formed Steel Residential Roof Trusses, L. Xu, H. Min

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

A computer-based optimal design approach for residential roof trusses using cold-formed steel C-sections is presented. The truss design is based on CSA S136-94 and the truss design guide published by the American Iron and Steel Institute and the Canadian Sheet Steel Building Institute. A genetic algorithm was adopted to obtain the minimum cost design with consideration to truss topology and member size simultaneously. The presented design examples demonstrate the applicability and efficiency ofthe proposed approach.

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Structural Stability Of Braced Scaffolding And Formwork With Spigot Joints, John Enright, Robert Harriss, Gregory J. Hancock Oct 2000

Structural Stability Of Braced Scaffolding And Formwork With Spigot Joints, John Enright, Robert Harriss, Gregory J. Hancock

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

Steel Scaffolding systems are often constructed from cold-formed circular hollow sections. The beams of this system are normally called "ledgers" and the columns are normally called "standards". To allow the system to be quickly erected on site, "spigot joints" are inserted in the standards. The spigot joints consist of smaller diameter tubes which slide into the larger diameter tubes to provide a safe connection under gravity load. However, the spigot joints may have a lack of fit, and when located midway between the ledgers, they can cause significant out-of-straightness in a standard. This PΔ effect may weaken the standard as …

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Buckling Of Cold Formed Stainless Steel Columns Under Concentric And Eccentric Loading, J. Rhodes, M. Macdonald, W. Mcniff Oct 2000

Buckling Of Cold Formed Stainless Steel Columns Under Concentric And Eccentric Loading, J. Rhodes, M. Macdonald, W. Mcniff

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

This paper describes the results obtained from a series of compression tests performed on cold formed stainless steel Type 304 columns of lipped channel cross-section. The cross-section dimensions, the column length and the eccentricity of the applied compressive load are varied to examine the effects on the buckling load capacity of the columns. The results obtained are compared to those obtained from the relevant design specifications in America and in Europe, and conclusions are drawn on the basis of the comparisons.

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The Development Of An Australian Standard For Stainless Steel Structures, Kim J. R. Rasmussen Oct 2000

The Development Of An Australian Standard For Stainless Steel Structures, Kim J. R. Rasmussen

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

The paper describes the recent development of an Australian standard for the design of cold-formed stainless steel structures. The standard is based on the ANSI/ASCE-8 (1991) Specification for the Design of Cold-formed Stainless Steel Structural Members but augmented to provide rules for cold-formed hollow section members and welded connections. Explicit design rules for the flexural buckling of compression members are also implemented. Further, mechanical properties are included for weldable chromium steels and austenitic-ferritic (duplex) alloys, which are in addition to the alloys included in the ANSII ASCE-8 Specification. The purpose of this paper is to summarise the new rules and …

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Mechanical Properties Of Stainless Steel Lipped Channels, M. Macdonald, J. Rhodes, G. T. Taylor Oct 2000

Mechanical Properties Of Stainless Steel Lipped Channels, M. Macdonald, J. Rhodes, G. T. Taylor

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

This paper describes and discusses the results obtained from a series of tensile tests performed on cold formed stainless steel Type 304 members of lipped channel cross-section. Standard tensile tests on coupons cut from the webs of the sections were carried out, as were full section tensile tests. Ramberg-Osgood type curves based on the procedure suggested in the ASCE design code were fitted to the stress-strain results and these are compared with the experimental results and Ramberg-Osgood type curves derived on an alternative basis.

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Automated Design Of Steel Trusses, B. Mobasher, S. D. Rajan, S. Y. Chen Oct 2000

Automated Design Of Steel Trusses, B. Mobasher, S. D. Rajan, S. Y. Chen

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

Designing an automated procedure for the optimal design of any structural system poses special challenges. Converting this methodology into a practical tool is even more challenging. In this research, a point-and-click software system is developed for the optimal design of roof truss systems. The starting point is a roof template containing minimal user input - outline of the truss, truss spacing, load information, and cost figures. A ground structure is constructed as the starting point of the design iterations. The Genetic Algorithm (GA) is used as the optimization tool to drive the design changes. Using the database of available sections, …

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Structural Behavior Of Cold-Formed Steel Header Beams For Residential Construction, Roger A. Laboube, Sutton F. Stephens Oct 2000

Structural Behavior Of Cold-Formed Steel Header Beams For Residential Construction, Roger A. Laboube, Sutton F. Stephens

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

The purpose of this experimental and analytical study was to observe the structural behavior of cold-formed steel header beams subject to a combined bending and interior-one-flange loading (IOF) condition as typically occurs in residential construction. This study focussed on the IOF loading of both back-to-back (I-beam) and box-beam configurations as specified in the "Prescriptive Method for Residential Cold-Formed Steel Framing - Second Edition." Past research conducted in the area of web crippling strength, bending strength and flange buckling of cold-formed steel members was reviewed and is discussed. The data obtained from the experimental study was analyzed and evaluated to determine …

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Dynamic Behaviour Of Floors With Cold-Formed Steel Joists, L. Xu, Z. Ling, W. C. Xie, R. M. Schuster Oct 2000

Dynamic Behaviour Of Floors With Cold-Formed Steel Joists, L. Xu, Z. Ling, W. C. Xie, R. M. Schuster

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

Presented in this paper are the results of a recent study carried out at the University of Waterloo on the performance of residential floors supported by cold-formed steel C-section floor joists. Both static and dynamic tests were conducted on steel floors with different span lengths based on different design criteria. The purpose of the static tests was to evaluate the stiffuess and load sharing among the joists, and the purpose of the dynamic tests was to evaluate the dynamic characteristics such as frequencies of the floor systems. To identify the critical parameters that contribute to the control of floor vibration, …

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Lateral Bracing Connections For C-Sections Subjected To Bending, B. Beshara, Roger A. Laboube Oct 2000

Lateral Bracing Connections For C-Sections Subjected To Bending, B. Beshara, Roger A. Laboube

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

The overall behavior under bending moment of cold-formed steel C-sections assemblies was investigated. Each test assembly consisted of C-sections acting as beams having a track to restrain the ends. Lateral bracing to restrain C-sections from rotation was provided at mid-span. To better understand the influence of the brace connection on the bending behavior, an experimental investigation was carried out with particular emphasis placed on the study of the effect of the mid-span brace connection on the bending behavior, and the effect of attaching dry wall to the tension flange. For the dry wall test specimens, lateral bracing was also provided …

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Professional Ethics: A Life-Long Pursuit By An Engineer, C.K. Leung, Jolly Wong Aug 2000

Professional Ethics: A Life-Long Pursuit By An Engineer, C.K. Leung, Jolly Wong

International Vocational Education and Training Association (IVETA) Conference

After an engineering student has finished the studies in a college, he (or she) is prepared to, usually with much enthusiasm and high hopes, embark into a new world to make use of what he has learnt for the betterment of the society and the engineering profession. The pursuit of the “Real”, the “Good”, and the “Beautiful” has been the highest goal. With the dawning of the e-Commerce and “Dot-Com” era, with the IT (Information Technology) heat sweeping through the world and catching everyone by surprise, and with the rapid replacement of traditional materialistic substances by their electronic and cyber …

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Author's Index, Multiple Authors Jun 1999

Author's Index, Multiple Authors

U.S. Mine Ventilation Symposium

No abstract provided.

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Gas Emission Control On Longwall Panels At The Vorkuta Coal Mines, V. N. Bobrovnikov, O. I. Kazanin, A. P. Veselov Jun 1999

Gas Emission Control On Longwall Panels At The Vorkuta Coal Mines, V. N. Bobrovnikov, O. I. Kazanin, A. P. Veselov

U.S. Mine Ventilation Symposium

The characteristics of geological conditions and mining technology at the coal mines of Coal Stock Company Vorkutaugol are given in the article. Information about longwall panel ventilation schemes and problems caused by high methane emission is also presented. The results of experiments at longwall panels using the methane emission control ventilation complex are described as well as ways of isolating gob methane removal. Other topics include the methane emission control ventilation complex consisted of drainage entry, an isolating wall with windows, mixing chambers and regulating stoppings. As results of experiments have shown, the most effective gas emission control methods were: …

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An Investigation Of Longwall Gob Gas Behavior And Control Methods, Steven J. Schatzel, William P. Diamond, Fred Garcia, John C. Lascola, Frank E. Mccall, Paul W. Jeran, Thomas P. Mucho Jun 1999

An Investigation Of Longwall Gob Gas Behavior And Control Methods, Steven J. Schatzel, William P. Diamond, Fred Garcia, John C. Lascola, Frank E. Mccall, Paul W. Jeran, Thomas P. Mucho

U.S. Mine Ventilation Symposium

The National Institute for Occupational Safety and Health (NIOSH) has initiated the use of a tracer gas in field studies to characterize geologic and mining factors influencing the migration of longwall gob gas. Three studies have been conducted using sulfur hexafluoride (SF6) at a coal mine in the Northern Appalachian Basin operating in the Pittsburgh Coalbed. Eight underground tracer gas releases and one gob gas venthole release are summarized. The results indicate that the gas flow in the bleeder network and in the interior regions of longwall panel gobs do not strongly interact and that the negative pressure …

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Flammable Gas Emissions In South African Gold And Platinum Mines Review Of Incidents And Accidents, A. P. Cook, C. F. Meyer, K. Balt Jun 1999

Flammable Gas Emissions In South African Gold And Platinum Mines Review Of Incidents And Accidents, A. P. Cook, C. F. Meyer, K. Balt

U.S. Mine Ventilation Symposium

Flammable gas emissions are relatively common and widespread across the South African gold and platinum mines, but a general lack of awareness has lead to an increase in flammable gas related accidents and fatalities over the last ten years. The gas is usually a mixture of hydrocarbons C1 to C4 with hydrogen, each in varying quantities, with methane and hydrogen predominant. The three most common causes leading to gas accidents are changes to the ventilation, lack of testing for gas, and contraband, with gas ignitions caused by contraband and illegal tampering with caplamps. Development work accounts for 70 percent of …

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Lowering Respirable Dust Exposures At Mineral Processing Facilities, Andrew B. Cecala, Robert J. Timko, Edward D. Thimons Jun 1999

Lowering Respirable Dust Exposures At Mineral Processing Facilities, Andrew B. Cecala, Robert J. Timko, Edward D. Thimons

U.S. Mine Ventilation Symposium

This article discusses three research projects performed by the National Institute for Occupational Safety and Health, (formerly the Bureau of Mines), that reduce the respirable dust exposure of plant workers at mineral processing facilities. All three of these projects are very different but they all have the same goal of reducing worker exposure to respirable dust at mineral processing facilities. The first project deals with a total mill ventilation system that reduces dust levels throughout an entire building and lowers the dust exposure of everyone working in the structure. The second project describes a bag and belt cleaner device that …

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An Integrated Approach To Control Diesel Particulate Matter In Underground Coal Mines, Pramod C. Thakur, Larry D. Patts Jun 1999

An Integrated Approach To Control Diesel Particulate Matter In Underground Coal Mines, Pramod C. Thakur, Larry D. Patts

U.S. Mine Ventilation Symposium

Diesel engines were introduced in European, Asian, and Australian coal mines nearly fifty years ago and more recently in U.S. coal mines. Their use minimizes the risks of mine fires and gas explosions associated with trolley wire haulage. While there is no epidemiological evidence that properly diluted diesel exhaust creates any health hazard, some concern persists about the long-term effects of inhaling diesel particulate matter. Existing control technology has been able to dilute all gaseous components of diesel exhaust to safe levels. Because there is no medically established threshold limit value for diesel particulate matter in U.S. coal mines, it …

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Personal Cooling In Hot Workings, Michael A. Tuck Jun 1999

Personal Cooling In Hot Workings, Michael A. Tuck

U.S. Mine Ventilation Symposium

The number of mines experiencing climatic difficulties worldwide is increasing. In a large number of cases these climatic difficulties are confined to working areas only or to specific locations within working areas. Thus the problem in these mines can be described as highly localised, due to a large extent not to high rock temperatures but due to machine heat loads and low airflow rates. Under such situations conventional means of controlling the climate can be inapplicable and/or uneconomic. One possible means of achieving the required level of climatic control, to ensure worker health and safety whilst achieving economic gains, is …

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Evaluation Of Discriminating Fire Sensors In Two Underground Coal Mines, William J. Francart Jun 1999

Evaluation Of Discriminating Fire Sensors In Two Underground Coal Mines, William J. Francart

U.S. Mine Ventilation Symposium

Fire detection in underground coal mines using carbon monoxide (CO) based monitoring systems has been very effective in many mines. Many systems have been able to detect fires in early stages of development at very low CO levels. However in mines which use extensive diesel haulage and support vehicles, the systems have been less sensitive to early detection due to diesel exhaust contaminants elevating baseline CO levels. A new technology has been tested in two underground coal mines which is designed to discriminate between the CO produced by diesel engines and CO from a fire by correcting the CO concentration …

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The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer Jun 1999

The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer

U.S. Mine Ventilation Symposium

This is the description of ventilation planning conducted by the author in 1952 as his thesis for the German degree of Dipl.-Ing. Since the problems have not changed, most of the work done is not much different from what one would do today. Even the tools have remained the same, except for the computers, which were not around yet. To compensate for this, certain planning techniques were developed which are now in danger of being forgotten.

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Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh Jun 1999

Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh

U.S. Mine Ventilation Symposium

Longitudinal ventilation systems in transit and rail tunnels are typically analyzed by one dimensional ventilation network simulation models, such as the Subway Environment Simulation (SES) program. However, in recent years computational fluid dynamics (CFD) modeling has been utilized in conjunction with one-dimensional ventilation network programs to study ventilation systems for large volume spaces such as transit stations and rail overbuilds, as well as for vehicular tunnels. CFD uses numerical methods to simulate complex fluid flow phenomena in three dimensions to predict the distribution of velocity, pressure, temperature, concentration, and other relevant variables throughout the volume. This paper presents an overview …

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Developments In Longwall Ventilation, Jürgen F. Brune, Joseph P. Aman, Mike Kotch Jun 1999

Developments In Longwall Ventilation, Jürgen F. Brune, Joseph P. Aman, Mike Kotch

U.S. Mine Ventilation Symposium

Rapid development in longwall mining technology has brought significant changes in panel layout and geometry. These changes require adaptations in the ventilation system to provide sufficient air quantities in longwall face and bleeder areas. At CONSOL, various longwall bleeder systems in the Pittsburgh No. 8 Seam have been studied with detailed ventilation surveys. Computer model network simulations were conducted from these surveys to study the effects of different bleeder configurations and ventilation adjustments. This paper examines the relationships between the longwall face air quantity and the convergence in the tailgate-to-bleeder entries, number of development entries, bleeder fan pressure and the …

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Replacement Of A Major Ventilation Raise At The Homestake Gold Mine, Justus B. Deen, John R. Marks, Leetta M. Shaffner Jun 1999

Replacement Of A Major Ventilation Raise At The Homestake Gold Mine, Justus B. Deen, John R. Marks, Leetta M. Shaffner

U.S. Mine Ventilation Symposium

Few tasks are more important to the Ventilation Engineer than planning major airways. This paper presents a case study of the inception, design, installation, cost and performance of a 253 m long, 4.27 m diameter subsurface replacement exhaust raise and its connecting drifts. The original raise served as a component of the primary exhaustway (140 m3/s) and heat rejection sink (8MW) for the deepest production district, responsible for 45% of the mine's total ounce production. The chronology of ground control problems with the original raise and attempts to halt the unraveling are described. Planning for a replacement raise commenced once …

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Effects Of Drilling Small Diameter Exhaust Shafts In A Gassy Longwall Operation, Tim Coleman, William Maloney Jun 1999

Effects Of Drilling Small Diameter Exhaust Shafts In A Gassy Longwall Operation, Tim Coleman, William Maloney

U.S. Mine Ventilation Symposium

As the title indicates, this paper deals with the ventilation of a gassy longwall mine through the use of small diameter exhaust shafts. Extensive background information is provided to show the evolution of the mine's ventilation system to correspond with changes in longwall mining techniques, particularly increases in face width. A description of the blind drilled shaft techniques, which proved to be the most economical ventilation choice for US Steel No. 50 Mine, is also included.

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Ventilation-On-Demand: Quantity Or Quality — A Pilot Trial At Barrick Gold's Bousquet Mine, Stephen G. Hardcastle, M. K. Gangal, Manfred Schreer, Paul Gauthier Jun 1999

Ventilation-On-Demand: Quantity Or Quality — A Pilot Trial At Barrick Gold's Bousquet Mine, Stephen G. Hardcastle, M. K. Gangal, Manfred Schreer, Paul Gauthier

U.S. Mine Ventilation Symposium

Common to many established mines in Canada, is the problem that their ventilation systems are continually being stretched to meet new needs that were not anticipated in the original design. This can be the result of a variety of different factors, such as the discovery of new reserves at depth, accelerated production, new worker exposure regulations or a change of mining method. At Bousquet, the ventilation of a new multilevel mining block over 1 km away from the existing bottom of the mine presents a challenge. The airflow available for this region is limited to 57 m3/s by …

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Novel Approach To The Energy Analysis Of Mine Cooling Strategies, C. T. Twort, I. S. Lowndes, S. J. Pickering Jun 1999

Novel Approach To The Energy Analysis Of Mine Cooling Strategies, C. T. Twort, I. S. Lowndes, S. J. Pickering

U.S. Mine Ventilation Symposium

The extraction of minerals and coal at increasing depth, employing higher-powered, mechanized machinery to increase production levels imposes an increased burden on the ability to maintain an acceptable mine climate. Any deterioration in the mine climate within working zones may adversely affect the health and safety of the workforce. The combination of the optimal design of the mine system layout, together with the selective application of suitable ventilation and cooling systems, may be used to control the climate within working zones. The adoption of mechanical cooling within mines is an expensive process in terms of both capital and operating costs. …

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Performance Assessment Of A Multi-Stage Cooling System At San Manuel Mine, Kuda R. Mutama Jun 1999

Performance Assessment Of A Multi-Stage Cooling System At San Manuel Mine, Kuda R. Mutama

U.S. Mine Ventilation Symposium

This paper describes the mine ventilation cooling system at San Manuel Mine, which has evolved as new deeper and hotter working levels were added to the mine, between 1979 -1997. The expansion philosophy was based on utilizing existing facilities, providing lower capital cost and operational convenience. The cooling system is comprised of three surface chillers of 10.55 Megawatts (3,000 tons) total cooling capacity. Cooling towers, also located on surface, ultimately reject all the heat from underground system. The chilled water is pumped to a shell and tube heat exchanger station located 915 metres underground in a high pressure circulating water …

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Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz Jun 1999

Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz

U.S. Mine Ventilation Symposium

Three mine explosions which occurred in the 1980s (1983 - McClure No. 1 Mine, Virginia; 1984 - Greenwich Collieries No. 1 Mine, Pennsylvania; and 1989- Pyro No.9 Slope Williams Station Mine, Kentucky) cost twenty lives. The authors, by investigating these three cases, found a common ventilation problem. This problem was the misunderstanding of the diagonal connections in the mine ventilation system (MVS). Based on the findings from these investigations, the authors explain the importance of diagonal connections in a MVS and discuss other factors that affected safety.

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