Dust control handbook for industrial minerals mining and processing

Throughout the mining and processing of minerals, the mined ore undergoes a number of crushing, grinding, cleaning, drying, and product sizing operations as it is processed into a marketable commodity. These operations are highly mechanized, and both individually and collectively these processes can generate large amounts of dust. If control technologies are inadequate, hazardous levels of respirable dust may be liberated into the work environment, potentially exposing workers. Accordingly, federal regulations are in place to limit the respirable dust exposure of mine workers. Engineering controls are implemented in mining operations in an effort to reduce dust generation and limit worker exposure.NIOSHTIC no. 2004022

Coastal Storm Activity along the Eastern North Island of New Zealand - East Cape to Wellington

Coastal storm activity for the eastern North Island, between East Cape and Wellington, has been quantified from a meteorological perspective through the use of cyclone tracks and extreme winds and from an oceanographic perspective by using hindcast wave information. It has culminated in the production of a high quality, digital coastal storm database for the eastern North Island. Together, this information provides a new understanding of coastal storm behaviour for the eastern North Island. A regional database of historical coastal storms along the eastern North Island between 1930 and 2005 (75 years) is now available in digital format. Coastal storms were identified as bouts of strong winds (greater than or equal to 10.5 m/s) from long-term local wind records from 1962 to 2005, and prior to this period, coastal storms were qualitatively recognised as any event leading to coastal shipping disruptions/delays, large wave conditions along the coast, episodes of coastal erosion and strong onshore wind periods. This digital database consists of five informative components that include storm meteorology, storm oceanography, impacts and damages, storm photo’s and images, and data sources. It has identified a set of five storm types for the eastern North Island consisting of Trough/Ridges, East Coast Lows, Subtropical Lows, Tasman Sea Lows, and Cyclone-Anticyclone pair. The two dominant types are Trough/Ridge and East Coast Low, with the Trough pattern involving weather systems primarily from the southern ocean, whilst East Coast Lows involve large cyclones off the coast that can be distantly generated (from the Tasman Sea or subtropics) or locally generated around NZ from southern ocean troughs. The most intense coastal storms off the eastern North Island are East Coast Lows involving cyclones from the subtropics. These storm events reveal blocking-type anticyclones east of the Chatham Islands play a vital role in coastal storm activity by steering cyclones southward towards NZ and then blocking any eastward movements so that cyclones become slow-moving off the east coast. These factors increase the intensity of pressure gradients directly over eastern NZ. The Gisborne region, for the 1962-1991 period (30 years), had an annual average of three coastal storms and displays peak activity in September. These storms are overwhelming from the south and southeast. A longer dataset of local winds at Wellington, spanning 1962-2005 (44 years), produced an annual average frequency of 9 coastal storms per year. The monthly distribution revealed peak storm activity in June and heightened activity between May and August. Both short-lived, high intensity storms (winds greater than or equal to 14.5 m/s for at least 12 hours) and long-lived, lower intensity storms (winds greater than or equal to 10.5m/s for at least 24 hours) were identified for the Wellington region. Approximately 70% of these coastal storms persisted for up to two days duration and are predominately from the south and southwest. Furthermore, the more exposed nature and steep terrain surrounding Wellington means a greater likelihood of higher intensity coastal storms compared to the Gisborne region. Strong cyclonic systems in the southwest Pacific cluster in the central Tasman Sea and east of the Chatham Islands in all seasons and are most frequent in winter. It is during winter that a clear frequency maximum is spotted over North Cape and appears to be related to the presence of slow-moving cyclones rather than high counts of discrete systems. Strong cyclones tend to form in the western Tasman Sea, in the subtropics near 22-23S, and near North Cape. This local formation off North Cape could be related to the Tasman front and North Cape eddy which create warm sea surface temperature anomalies. The complete life cycle of all strong cyclones shows formation, intensification and maturity in the western-central Tasman Sea, and therefore, a large proportion of these cyclones approaching NZ are weakening systems. However, local generation and intensification near North Cape and the Chatham Islands ensures strong cyclones continue to influence eastern NZ, and further indicates weakened Tasman Sea cyclones can drive coastal storm events through interactions with ridges and high pressure systems. Strong cyclones are most frequent around NZ in August when an average of 4-5 systems per month occurs. Extreme onshore winds off the eastern coast of NZ consist principally of winds from the southwest and south with a single high latitude frequency maximum near the dateline. These winds are generated from southern ocean cyclonic activity and their northward-extending troughs that pass over NZ, and their spread onto eastern NZ means they likely represent intense coastal storm events. Southeast, east and northeast winds rarely reach up to and beyond 20 m.s-1 over the seas to the east of NZ and generally cluster north of 40-45S indicating both subtropical and higher midlatitude source mechanisms. Extreme southeast winds are generated by the eastern flanks of large anticyclones that occupy the western Tasman Sea or large anticyclones south of the Chatham Islands. The principal frequency maximum of east and northeast winds is remote from NZ appearing near 165°W, and represent distant generation areas for large swell events (rather than coastal storm activity). These winds that occur over northern NZ are associated with a Tasman Sea or subtropical cyclone off North Cape in combination with a large anticyclone or ridge over/or east of the South Island. In contrast, the distant core for eastward of NZ are generated off the backs of large anticyclones with a trough or cyclone on its northern flank. The deep-water wave climate off the eastern North Island is dominated by waves from the south. Between 9 and 13 large wave events occur each year between East Cape and Wellington and are most likely in the months of May, June and July. In contrast, large storm waves from the southeast, east and northeast have annual average frequencies of 1-3 events. The Gisborne coast was found to be the most exposed with large deep-water waves (greater than or equal to 3m) coming from the northeast through to the southwest. However, waves from the south and southwest are the largest and most persistent. The meteorology creating these waves are southern ocean troughs whilst the less frequent waves from the easterly quarter involve low pressure systems east or northeast of NZ. The different proxies for studying coastal storms all have shortfalls and arrive at different levels of coastal storm activity. It is suggested here that an optimal mix of these proxies can be used to identify damaging coastal storms along the eastern North Island

Dust control handbook for industrial minerals mining and processing

"This handbook was written by a task force of safety and health specialists, industrial hygienists, and engineers to provide information on proven and effective control technologies that lower workers' dust exposures during all stages of mineral processing. The handbook describes both dust-generating processes and the control strategies necessary to enable mine operators to reduce worker dust exposure. Implementation of the engineering controls discussed can assist operators, health specialists, and workers in reaching the ultimate goal of eliminating pneumoconiosis and other occupational diseases caused by dust exposure in the mining industry. Designed primarily for use by industrial minerals producers, this handbook contains detailed information on control technologies to address all stages of the minerals handling process, including drilling, crushing, screening, conveyance, bagging, loadout, and transport. The handbook's aim is to empower minerals industry personnel to apply state-of-the-art dust control technology to help reduce or eliminate mine and mill worker exposure to hazardous dust concentrations - a critical component in ensuring the health of our nation's mine workers." - NIOSHTIC-2NIOSHTIC no. 20055113Suggested citation: NIOSH [2019]. Dust control handbook for industrial minerals mining and processing. Second edition. By Cecala AB, O\u2019Brien AD, Schall J, Colinet JF, Franta RJ, Schultz MJ, Haas EJ, Robinson J, Patts J, Holen BM, Stein R, Weber J, Strebel M, Wilson L, and Ellis M. Pittsburgh PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2019\u2013124, RI 9701. https://doi.org/10.26616/NIOSHPUB2019124201910.26616/NIOSHPUB2019124606

Aeronautical engineering: A continuing bibliography with indexes (supplement 282)

This bibliography lists 623 reports, articles, and other documents introduced into the NASA scientific and technical information system in Aug. 1992. The coverage includes documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems. It also includes research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles

Water bath modelling of transient and time dependent natural ventilation flows

Since electricity was first harnessed, humanity has developed a lifestyle which can not exist without it. Traditionally, electricity has been created by burning fossil fuels which produces waste gases including carbon dioxide. These waste gases have accumulated in our atmosphere and are theorised to have contributed to a warming of the earth, causing a 0.4°C rise in average surface temperature since the 1970’s (DECC 2013). A warming of the earth is thought to lead to increased frequency of catastrophic weather events such as droughts and heat waves, leading to many deaths (Met Office 2015). In recent years, there has been a drive to reduce our dependence on the burning of fossil fuels by making technologies more efficient, developing methods of electricity generation which do not involve the burning of fossil fuels as well as replacing techniques requiring high energy demands with low energy techniques. Natural ventilation is one such low energy technique which can replace more electricity intensive strategies such as mechanical ventilation and air conditioning whilst still ensuring a room which is neither too cold nor too warm and removes pollutants. [...continued

Dielectric-barrier discharge plasma actuators for turbulent friction-drag manipulation via spanwise oscillations

Ein Plasmaaktuator wird über instationäre Betriebsmodi angesteuert, um wandnahe Fluidoszillationen zu erzeugen. Das Ziel ist es, spannweitig oszillierende Wände zugunsten einer Verringerung des turbulenten Reibungswiderstands nachzuahmen. Da der Aktuator keine beweglichen Teile besitzt, könnte er sich als nicht-mechanischer Ersatz der oszillierenden Wand eignen. Die Kombination von Betriebsmodus und zugrundeliegender Elektrodenanordnung ist eine Neuerung, welche die spannweitige Homogenität der Strömung solcher virtuellen Wandoszillationen verbessert. Die mechanische Charakterisierung wird mittels eines planaren Feldmessverfahrens durchgeführt, um sowohl die induzierten Strömungstopologien als auch die Effekte von Volumenkraft und „virtueller Wandgeschwindigkeit“, d.h. Reaktion des Fluids, aufzuzeigen. Daraus wird zur Bewertung und Optimierung der Leistungsfähigkeit des Aktuators ein universelles Diagramm hinsichtlich aktuatorspezifischer Parameter abgeleitet. Da die berechnete Volumenkraft die Art der Kraftausübung gut widerspiegelt, kann diese modellhaft zu verbesserten numerischen Simulationen der Aktuatorik dienen. Ferner wird eine neue Vorgehensweise für die Bestimmung der elektrischen Leistung von Aktuatoren mit mehreren Hochspannungselektroden bereitgestellt, welche die potenzielle Abschätzung des Nettogewinns in aktiven Kontrollszenarien ermöglicht. Zuletzt wird die unmittelbare Auswirkung der oszillatorischen Kraftausübung auf den Reibungswiderstand in der Querebene einer voll entwickelten turbulenten Kanalströmung mittels einer stereoskopischen Feldmesstechnik untersucht. Im Wesentlichen verbleibt die Strömung im sich entwickelnden Stadium und erfährt auf dem Aktuator eine Erhöhung des Reibungswiderstands, während sich dieser stromab des Aktuators verringert

Aeronautical Engineering: A continuing bibliography with indexes, supplement 128, November 1980

This bibliography lists 419 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1980

Spatial and Temporal Development of Saltation in Air.

PhDA resurgence of interest in the concept of equilibrium in the aeolian saltation system has been witnessed in the 1990's. Throughout the aeolian field of research, i. e. wind tunnel, field and numerical models, many highly successful individual investigations have been conducted. Despite these data, however, the timing and location of the mass flux equilibrium have not been quantified. This research investigates the simultaneous downwind spatial and temporal developments of the aeolian saltation system. Experiments were conducted in the laboratory and the field. By unification of the spatial and temporal dimensions in both environments one of the major limitations of contemporary aeolian science, the inability to relate data from different experimental environments, is addressed. In the wind tunnel the development of the saltation system was measured over a streamwise length of 8m. Sediment transport was measured at 1m intervals by the downwind deployment of seven Aarhus sand traps. In the field the development of the saltation system was monitored over distances of 10m and 20m. Mass flux was measured by the downwind deployment of five 'total load' sand traps. In both environments temporal wind velocity and mass flux data were collected simultaneously at a single site. Spatial profile velocity data were later obtained by a streamwise traverse along the experimental area. The downwind spatial development of the saltation system, from a point of initiation, in the laboratory and the field is manifest by an overshoot in mass flux and shear velocity. It is shown that in both environments mass flux increases with distance to a maximum at 4m downwind. This result is in remarkable agreement with existing data of a comparable scale. In the wind tunnel and the field experiments it V' is found that shear velocity overshoots between 2-4m downwind of the overshoot in mass flux. The distance between the overshoot in mass flux and the overshoot in shear velocity is termed the 'separation distance'. The existence of a 'separation distance' between the overshoots of mass flux and shear velocity questions the appropriateness of traditional mass flux formulae. It is found that conventional mass flux relationships with shear velocity, generated from data collected simultaneously at the same site, have the lowest predictive capability. The greatest confidence in the ability of shear velocity to predict the rate of mass flux is shown to occur when shear velocity data are collected downwind of mass flux data. The critical distance between the data collection points is demonstrated to be defined by the 'separation distance'. The downwind spatial development of the saltation system without a point of initiation in the laboratory and the field is influenced by sand entering from upwind. The existence of high energy bombardment by saltation processes throughout the experimental area is shown to produce an accelerated development of the saltation system. It is found that the precise downwind development of mass flux and shear velocity are dependent on the exact rate of sand entering from upwind. The temporal development of the saltation system is controlled essentially by the availability of transportable grains from the sand bed. In both the wind tunnel and the field experiments it is demonstrated that the saltation system develops through time from a transport-limited to a supply-limited system. The depletion of the sand bed through time limits the existence of the state of equilibrium. The equilibrium concept is thus shown to be inappropriate for the universal prediction of mass flux

Microgravity: A Teacher's Guide With Activities in Science, Mathematics, and Technology

The purpose of this curriculum supplement guide is to define and explain microgravity and show how microgravity can help us learn about the phenomena of our world. The front section of the guide is designed to provide teachers of science, mathematics, and technology at many levels with a foundation in microgravity science and applications. It begins with background information for the teacher on what microgravity is and how it is created. This is followed with information on the domains of microgravity science research; biotechnology, combustion science, fluid physics, fundamental physics, materials science, and microgravity research geared toward exploration. The background section concludes with a history of microgravity research and the expectations microgravity scientists have for research on the International Space Station. Finally, the guide concludes with a suggested reading list, NASA educational resources including electronic resources, and an evaluation questionnaire