Engineering Commons^™

The Training Of Marine Engineers : Present Methods And Future Directions In Developing Countries (Africa), Yassin Magongo Songoro

World Maritime University Dissertations

No abstract provided.

Developing An Effective Mechanism Of Oil Pollution Management In The Niger Delta, Ja'afaru Labaran Daura

World Maritime University Dissertations

No abstract provided.

Geombinatoric Aspects Of Processing Large Images And Large Spatial Databases, Jan Beck, Vladik Kreinovich, Brian Penn

Departmental Technical Reports (CS)

Computer processing can drastically improve the quality of an image and the reliability and accuracy of a spatial database. A large image (database) does not easily fit into the computer memory, so we process it by downloading pieces of the image. Each downloading takes a lot of time, so, to speed up the entire processing, we must use as few pieces as possible.

Many algorithms for processing images and spatial databases consist of comparing the value at a certain spatial location with values at nearby locations. For such algorithms, we must select (possibly overlapping) sub-images in such a way that …

Modeling Of Solid Phase Detonations, C. Richter, Hendrik J. Viljoen, N. F. J. Van Rensburg

Papers in Reaction Kinetics

In contrast to conventional explosives which constitute rapid decomposition of the molecular structure acconlpanied by the release of large volumes of gaseous products, heterogeneous mixtures in the SHS realm react by progression of a thermal wave at velocities far below the speed of sound in such mixtures. Interestingly, ultrafast solid phase reactions can be initiated under the right conditions. A shock wave compresses the solid mixture to densities well beyond the theoretical mean ambient density (TMD) and compression becomes the major form of preheating. In addition, elastic potential energy is pumped into the lattice structure to induce severe distortion and …

Santa Clara Magazine, Volume 41 Number 2, August 1999, Santa Clara University

Santa Clara Magazine

8 - APOCALYPSE PAST: Y1K By Thomas Turley. The year 2000 is upon us. But what about Y1K? History Professor Thomas Turley takes an historical look at the millennial fever of a thousand years ago.

12 - THE FUTURE IS MATH By Susan Vogel. Math Lecturer David Sul is on a mission: to get more Hispanics and African-Americans into Calculus and onto college through SCU's Calculus 100 program.

16 - The Class of 1999 Moves On By Sug Ramire '98. Optimism is the byword for the last graduating class of the millennium. Six 1999ers share their impressions, hopes, and fears …

A Comparison Of Air Leakage Prediction Techniques For Auxiliary Ventilation Ducting Systems, A. D. Stewart Gillies, Hsin Wei Wu

U.S. Mine Ventilation Symposium

This paper briefly reviews prediction techniques for determination of leakage and friction along auxiliary ventilation ducting systems. In order to compare various prediction techniques that have been developed over the past, a macroscopic investigation of air leakage and friction resistance of auxiliary ventilation ducting systems has been undertaken. Measurements were conducted on 450 and 915 mm diameter fabric ducting over 100 m duct length to determine frictional resistances and the extent of leakage. Due to the high degree of accuracy required and the large volume of data that needed to be collected, electronic pressure transducers were used with computer for …

Controlled Recirculation In Deep South African Gold Mines, Mark Butterworth

U.S. Mine Ventilation Symposium

Despite the many advantages and potential benefits of using controlled recirculation in Deep South African gold mines the strategy has found little favour. Indeed, controlled recirculation of air is at present rarely considered as an option in the planning and implementation of these underground ventilation systems. This paper broadly examines controlled recirculation, the benefits and advantages that could accrue from its use, reasons that may detract from its use and some solutions for addressing shortcomings. A brief historical review of controlled recirculation in the context of the South African gold mining industry is given. The advantages, which could result from …

Environ 2.5 — A Mine Ventilation And Cooling Network Simulation Tool, W. M. Marx

U.S. Mine Ventilation Symposium

As mining operations progress, ore reserves are depleted and alternative are almost invariably found at increasing depth and a host of attendant difficulties in this regard face· the mine operator. Most significant among these is the control of the increasingly hostile environment encountered at depth in terms of both ground behaviour and the increasing hot environment. To enable the practical and economical design of mine ventilation and cooling systems, ventilation practitioners need effective and efficient tools to perform their duty. One such tool is the Environ 2.5, an interactive network simulation program that allows for the simultaneous simulation of airflow …

Management Of Mine Explosion Risks, Jan J. L. Du Plessis, J. W. Oberholzer

U.S. Mine Ventilation Symposium

The management of explosions in the underground mining environment has been a high priority for managers since the turn of the century. In the early 1900s explosions, worldwide, reached catastrophic dimensions. In a number of large explosions more than 1000 people have died. In the early years of research, the basics of why explosions occurred were investigated and the participation of coal dust in underground coal mine explosions was proved. Taffanel, a French researcher, was one of the pioneers in establishing the use of stone dust and was instrumental in the design and development of the first stone-dust barriers. Throughout …

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 …

Rapid Extinguishing Of Sponcom Fires In Underground Mines, Zygmunt Kajdasz, George Zieba

U.S. Mine Ventilation Symposium

The main purpose presented in this paper is to present active and passive methods to fight a sponcom fire. The active method uses an inert gas generator called the GAG while the passive method is through the use of ventilation software. In most sponcom situations a combination of these two methods results in rapid extinguishing of the overheated areas. The presented software allows for accurate and "real time" analysis of the ventilation network. Application of the GAG has been proven on many occasions as an effective means of large volumes of mine atmosphere.

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 …

A Proposed New Method To Determine The Effectiveness Of In-Heading Methane Control, F. J. Van Zyl

U.S. Mine Ventilation Symposium

Various methods have been derived to determine the effectiveness with which ventilation systems clears headings of methane in a bord-and-pillar sections. A problem with applying these methods in underground sections is that the either require the face-area air quantity to be measured, which is virtually impossible in South African collieries, or they were developed for test galleries, making it difficult to use in production sections. Taking this into consideration the methane safety index (MSI) method was developed. The method utilizes methane data recorded around an active continuous miner (CM) and an activity log of cm operations to quantitatively assess methane …

Evaluation Of A Continuous Miner Half-Curtain Dust Control System In A South African Underground Coal Mine, Bharath K. Belle, J. J. L. Du Plessis

U.S. Mine Ventilation Symposium

The issues of public health and safety in the mining industry have been dealt with around the world through the intervention of governments. In 1997 the South African Department of Minerals and Energy (DME) sent out a directive to reduce the dust concentration level to /m³ at the operator's position for the sampling period. The reasons for the difficulty with compliance are: long headings up to 35m, inherently high dust generation rates of coal, and the increased use of highly mechanized equipment. A project was formulated under SIMRAC auspices with the title of "Underground Mechanical Miner Environmental Control" to …

Axial Fan Monitoring By Pressure Transients Close To The Blades, A Preliminary Study, Ian Loomis, Shaun Ramsay

U.S. Mine Ventilation Symposium

As the axial fan blades move within the fan case pressure transients are developed, which can be measured and qualified by a fixed point monitor. The nature of the pressure transient pattern observed close to the fan blade varies with the location on the fan performance curve. Measurement of the pressure fluctuation around the fan blade ring reveals the minute variation in pressure associated with the movement of the air within the fan. Such observations could be the basis for an on-line fan monitoring system based on the acoustic emissions from the fan blade. This paper describes a preliminary study …

Performance Of Distributed Bagged Stone Dust Barrier In Combating Coal-Dust Explosions, Jan J. L. Du Plessis, Pierre S. Vassard

U.S. Mine Ventilation Symposium

The Kloppersbos Research Facility of the CSIR's Division of Mining Technology has developed a new method of building stone dust barriers. The new barrier makes use of a previous concept of containing stone dust in a bag, but incorporates a new method of rupturing the bag. This was achieved by adapting the closing mechanism and by balancing the stone dust content with the void in the bag. The bagged barrier was extensively tested in the 200-m test gallery. During these tests, it became evident that these bags could be made to rupture and spread stone dust when subjected to smaller …

An Integrated Strategy For Emergency Egress From An Underground Metal Mine, Rick Brake

U.S. Mine Ventilation Symposium

The fact that major fires are rare events in underground metal mines means there is often little on-site experience in dealing with these situations. Elaborate strategies that rely on a high degree of training at all levels to be effective are likely to fail, especially with the trend in Australia towards smaller mines and "fly in-fly out" operations. A robust strategy is required. The key items in such a strategy are: early detection and warning of personnel, personal belt-worn oxygen-generating self-rescuers, high integrity escape routes and self-contained refuge stations, simple procedures, reliable personnel ''tagging" systems and sufficient, trained, search and …

Characteristics Of Airborne Dust In The Return Airways Of The Mechanized Longwall Face, Tevfik Güyagüler, Sinan Keskin

U.S. Mine Ventilation Symposium

In this paper the results of a research study on the characterisation of airborne dust in the return airway of the mechanized longwall face at Middle Anatolian Lignite Mine, OAL are presented. Dust, temperature, moisture and air velocity measurements were carried out in the return airways of the fully mechanized longwalls. Then the analyses of results on real-time concentration data, mass concentration data, effect of moisture, heat and air velocity on dust concentration are made. It has been found that amount of dust in return airway is directly related to the face activities and to the amount of settled dust …

Increased Methane Emissions For Mechanical Miners Working In Burnt Coal, A. P. Cook

U.S. Mine Ventilation Symposium

An intensive research programme has quantified the methane conditions around mechanical miners in production conditions. Methane seam gas contents show an increase of up to 26 times when mining burnt coal compared with normal increase in emission rates. Coal seam methane contents at the face increased from 1 m³/t to 6m³/t in one section, and from 0.1 m³/t to 2.6 m³/t in another. Emission rates from burnt coal were as high as 300 lit/min as it was mined. These increases in content and emission occur immediately after cutting into the burnt coal. …

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 …

Culture And The Management Of Advanced Automation: An Analysis Of Two Airlines, Surendra Cudah Ratwatte

Master's Theses - Daytona Beach

The purpose of this study was to investigate the relationship between National, Organizational and Professional Cultures and the attitudes toward managing advanced automation among the flightcrew of two international airlines. The Flight Management Attitudes Questionnaire developed by the University of Texas was utilized to determine the attitudes and perceptions held by airline pilots of various nationalities who fly late model Airbus and Boeing airliners. A census survey was conducted at the crew bases of the two airlines, one in the Middle East and other in South Asia. A total of 230 completed surveys were received. Chi Square analysis was used …

Bs News

Building Services Engineering

No abstract provided.

A Performance Analysis Of Dynamic Routing Algorithms In An Iridium-Like Low Earth Orbit Satellite System, Stephen R. Pratt

Theses and Dissertations

This research presents a first of its kind comparative analysis of the Extended Bellman-Ford and Darting algorithms, using the Iridium low earth orbit (LEO) satellite system configuration for the simulation environment. The algorithms are compared to one another via discrete-event computer simulation and evaluated based on their ability to route real-time voice communications under low, medium, and high network loading conditions. The algorithms' ability to meet real-time voice constraints is evaluated with a full and degraded satellite constellation using an algorithmic satellite removal method. The investigation results indicate that both algorithms are suitable for use in a LEO environment and …

A Validation Assessment Of Thunder 6.5'S Intelligence, Surveillance, And Reconnaissance Module, Francine N. Nelson

Theses and Dissertations

A validation assessment of THUNDER 6.5's Intelligence, Surveillance, and Reconnaissance (ISR) module is accomplished using formulational and experimental validation techniques. A comparison of ISR purposes and processes according to military doctrine is made with the purposes and processes of ISR implemented within THUNDER 6.5. This comparison provides an overview of the process, an understanding of the level of aggregation within THUNDER, insight into possible problem areas in THUNDER, and a basis for improving THUNDER ISR processes. Sensitivity analysis of the ISR parameters as they relate to the Quality, Quantity, and Timeliness of ISR is also presented to provide insight into …

A Comparative Analysis Of The Iridium® And Globalstar® Satellite Transmission Paths, Kenneth E. Crowe

Theses and Dissertations

Globalstar and Iridium will provide valuable global communications assets for business, humanitarian aid and military operations. However, the level of coverage and the quality of the transmission path of these systems are strongly dependent on the latitude of the user and, due to their orbital characteristics, both systems provide reduced levels of coverage at low latitudes. Additionally, the L- and S-Band frequencies utilized by these systems are prone to ionospheric interference at low latitudes. The results of extensive simulation analysis indicate that the Globalstar constellation architecture provides a considerably better transmission path than Iridium's in several important areas, including path …

Ccfss News February 1999, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

A Cloud-Removal Algorithm For Ssm/I Data, David G. Long, Douglas L. Daum, Quinn P. Remund

Faculty Publications

Microwave radiometers, while traditionally utilized in atmospheric and oceanic studies, can also be used in land surface applications. However, the problem of undesirable atmospheric effects caused by clouds and precipitation must be addressed. In this paper, temporal composite surface brightness images are generated from special sensor microwave/imager (SSM/I) data with the aid of new algorithms to eliminate small-scale distortion caused by clouds or precipitation. Mean, second-highest value, modified maximum average (MMA), and hybrid compositing algorithms are compared. The effectiveness of each algorithm is illustrated through simulation and real data distribution analysis. The results show that the second-highest value algorithm is …

Neurocontrol Of Turbogenerators With Adaptive Critic Designs, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a neuro-controller for a turbogenerator using a novel technique based on adaptive critic designs (ACD). This adaptive critic design based neuro-controller augments/replaces the traditional automatic voltage regulator (AVR) and the turbine governor of the generator. Simulation results are presented to show that neural network controllers with the ACD have the potential to control turbogenerators when system conditions and configuration changes.

Problems Of Irrigation In Developing Countries, Phillip Z. Kirpich, Dorota Z. Haman, Stuart W. Styles

BioResource and Agricultural Engineering

This paper describes the crucial importance of irrigated agriculture to developing countries and to the world as a whole. This is followed by a summary of key problems that restrict and diminish the benefits of irrigated agriculture. Solution of these problems will above all require a holistic approach and will require changes in the institutions involved. These institutions include those of the developing countries, of the developed countries that provide aid, and of the international financing and technical-assistance agencies. Engineers in the developed countries have had, and will continue to have, a leading role but will need some redirection. ASCE …

Predicting The Unconfined Compressive Strength Of The Breathitt Shale Using Slake Durability, Shore Hardness And Rock Structural Properties, Engin C. Koncagül, Paul M. Santi

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Compressive strength is the most widely used design parameter in the construction industry and in rock engineering. For example, Bieniawski [Bieniawski, Z.T., Estimating the strength of rock materials, Is. J. S. Afr. Inst. Min. Metall., 1974, 74, 312-320.] reported that mining engineers request the uniaxial compressive strength (UCS) more often than any other rock property. However, standards set for specimen preparation are very demanding. Therefore, it is quite difficult and sometimes impossible to fulfill these requirements using weak rocks and especially shales. This paper evaluates the use of the slake durability and Shore hardness tests to estimate UCS, based on …