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Exposure to fumes and gases during welding operations.Sutherland, Robert Allan, mikewood@deakin.edu.au January 1998 (has links)
The exposure to fumes and gases is one of the hazards associated with welding operations. Apart from research conducted on the mechanism of fume and gas formation and the relationship between fume formation rates and common welding parameters, little is known about the exposure process during welding.
This research project aimed to identify the factors that influence exposure, develop an understanding of their role in the exposure process and through this understanding formulate strategies for the effective control of exposure during welding. To address these aims a literature review and an experimental program was conducted The literature review surveyed epidemiological, toxicological and exposure data. The experimental program involved three approaches, the first, an evaluation of the factors that influence exposure by assessing a metal inert gas/mild steel welding process in a workshop setting. The second approach involved the study of exposure in a controlled environment provided by a wind tunnel and simulated welding process. The final approach was to investigate workplace conditions through an assessment of exposure and control strategies in industry.
The exposure to fumes and gases during welding is highly variable and frequently in excess of the health based exposure standards. Exposure is influenced by a number of a factors including the welding process, base material, arc time, electrode, arc current, arc voltage, arc length, electrode polarity, shield gas, wire-to-metal-work distance (metal inert gas), metal transfer mode, intensity of the UV radiation (ozone), the frequency of arc ignitions (ozone), thermal buoyancy generated by the arc process, ventilation (natural and mechanical), the welding environment, the position of the welder, the welders stance, helmet type, and helmet position. Exposure occurs as a result of three processes: the formation of contaminants at or around the arc region; their transport from the arc region, as influenced by the entry and thermal expansion of shield gases, the vigorous production of contaminants, thermal air currents produced by the heat of the arc process, and ventilation; and finally the entry of contaminants into the breathing zone of the welder, as influenced by the position of the welder, the welders stance, helmet type, and the helmet position. The control of exposure during welding can be achieved by several means: through the selection of welding parameters that generate low contaminant formation rates; through the limitation of arc time; and by isolating the breathing zone of the welder from the contaminant plume through the use of ventilation, welder position or the welding helmet as a physical barrier. Effective control is achieved by careful examination of the workplace, the selection of the most appropriate control option, and motivation of the workforce.
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Performance evaluation of heterogeneous wireless local area network systemsPaotrakool, Kittiporn 17 December 2002 (has links)
The market for Wireless Local Area Networks (WLANs) has experienced
tremendous growth over the last few years and this trend is expected to continue
in the future. This growth is due to the fact that wireless LANs provide several
benefits including mobility, efficiency, and accuracy. In addition, the cost of
installation for wireless LANs is several orders of magnitude lower than with
traditional wired LANs due to reduced cabling costs.
The two major components of a WLAN are Access Points (APs) and
Radio Cards (RCs). Efforts have been made in the past to assess the performance
of different APs and RCs from different vendors. However, these evaluations
have been restricted to tests of interoperability and roaming. Tests to assess
performance with respect to range, throughput, and power consumption are less
common. Moreover, these tests are usually performed using homogeneous test
beds (i.e., hardware components belong to the same vendor).
The objective of this research was to assess how commercial-off-the-shelf
(COTS) WLAN systems perform with respect to interoperability, roaming ability,
power consumption, throughput, and range. In order to accomplish this, a test
procedure composed of five experiments was developed. The evaluation was
performed not only on homogeneous systems but also on systems constructed
with hardware components from different vendors (i.e., heterogeneous).
The results of the performance tests indicated that the different AP, RC,
and their combinations, significantly affect the performance of the WLAN
systems with respect to range, throughput, and power consumption. No
significant differences were observed in the WLAN systems with respect to
interoperability or roaming.
The results of this research will help decision makers in understanding the
key parameters that have to be considered when selecting WLAN equipment. In
practice, however, it would be difficult for decision makers to determine which
vendor of WLAN equipment has the best solution without actual testing. / Graduation date: 2003
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Putting technology to work : experiences of people using assistive technology in the workplace /De Jonge, Desleigh. January 2001 (has links) (PDF)
Thesis (M. Phil.)--University of Queensland, 2001. / Includes bibliographical references.
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Computer driven video graphicsChan, Kai-wah, 1952- January 1978 (has links)
No description available.
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Evaluation of impact attenuation of facial protectors in ice hockey helmetsLemair, Mylene. January 2006 (has links)
The purpose of this study was to investigate whether ice hockey facial protectors can decrease overall head acceleration during blunt impacts as well as to identify if attenuation differences exist between visors and cages. Commercial models of three cages and three visors were assessed. Blunt impacts were simulated permitting the measurement of peak accelerations (PA) within the surrogate head form. Results indicated that indeed face protectors in combination with helmets substantially reduced PA during blunt impacts within threshold safety limits (below 300 g's). In general, cages showed lower PA than visors (p=0.004). Differences between models were also observed during repeated impacts and impact site (p=0.0001, p=0.007). In conclusion, this study demonstrates that facial protectors function beyond their role in preventing facial injuries, complementing the role of the helmet in attenuating head deceleration during impact. Consequently, the utilization of facial protectors may reduce the severity and incidence of mTBI.
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Detection of needle wear in an automated sewing processGunn, Bernard January 1991 (has links)
No description available.
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The design and operation of equipment for the chemical processing of flaxAhern, Lawrence Richard 05 1900 (has links)
No description available.
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Design of a manipulator for remote solid waste collectionHar-Oz, Pinhas Horshovski 05 1900 (has links)
No description available.
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Development of a noise rejecting sensor for conformal hull arraysVinamata, Xavier F. 12 1900 (has links)
No description available.
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Air conditioner condenser optimizationPropst, James Lawson 08 1900 (has links)
No description available.
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