How relevant are engineering samples in the management of personal dust exposure?

A directive, legislated by the South African Department of Minerals and Energy(DME) in 1997, was introduced to reduce the dust exposures of continuous miner(CM) operators to below 5 mg/m3, when measured at the operator's cab position. The focus of this paper is to review the effectiveness of observing this rule for almost two decades and discuss industry perceptions arising from the application of this rule. The results have demonstrated that the engineering sample cannot predict the personal shift dust exposure of a CM operator. Therefore, it is recommended that the engineering sampling, as currently practiced,should be reviewed with the objective to discontinue and replace it by the approved PDM3700 realtime dust monitor.     

Numerical modelling of wind and dust patterns around a full-scale paraboloidal solar dish

This study reports on numerical predictions of velocity and pressure fields, and dust particles trajectories in steady and unsteady flows around a full-scale paraboloidal solar dish. Calculations are performed for three wind speeds of 4.16, 9.72, and 15.2 m s⁻¹, and dish pitch angles from 0° to 180°. The flow field structure, lift and drag coefficients are calculated for each flow configuration. Using the predicted mean flow velocity field, analytical expressions for the aerodynamic coefficients, as a function of the pitch angle, are developed. The unsteady-state flow is characterised by formation of stable vortices behind the dish for most flow configurations, except at 60° and 150° pitch angles. At these angles vortex-shedding occurred with a strong flow oscillation extending downstream the dish. The calculations of dust particles trajectories provide a qualitative assessment of the deposition rate, dish orientation, and surface locations where dust accumulation is most likely to occur. The study also presents an initial assessment of the effectiveness of various windbreaks installed upstream of the dish in reducing aerodynamics drag.     

Inerting of magnesium dust cloud with Ar, N2 and CO2

Experiments were conducted on the inerting of magnesium dust with N₂, CO₂, and Ar. Comparing the maximum explosion pressure, maximum rate of pressure rise, and limiting oxygen concentration with different inertants, it was determined that Ar is not the best inert gas under all conditions as commonly believed. N₂ was more effective than Ar as an inertant. CO₂ provided more inerting effect than either Ar and N₂ in low magnesium dust concentrations, although explosibility was increased at higher dust concentrations. Both N₂ and CO₂ as inerting agents showed higher LOC values than Ar. These results indicated that N₂ is a more economical inerting gas than Ar for the tested coarse magnesium dust.     

Stenotrophomonas,Mycobacterium, and Streptomyces in home dust and air: associations with moldiness and other home/family characteristics

Respiratory illnesses have been linked to children's exposures to water‐damaged homes. Therefore, understanding the microbiome in water‐damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water‐damaged homes. We collected air and dust samples in twenty‐one low‐mold homes and twenty‐one high‐mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp., and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, that is, with higher floor surface moisture and higher concentrations of moisture‐related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria.     

熔融还原中流态化预还原系统返料集尘器冷模试验研究

流化炉尾气中矿粉的回收是实现二步熔融还原工艺的关键技术之一。本文对扩大式旋风集尘器冷模试验的主要设计参数进行了量钢分析,并用计算机对试验数据进行逐步回归处理,得到扩大式旋风集尘器的数学模型。在最佳试验条件下,旋风集尘器冷模的集尘率可达94.9%,为扩大试验装置的设计提供了可靠的设计参数。     

云锡矿山井下粉尘浓度统计分析

本文采用数理统计方法,对各作业的粉尘浓度及分布:不同工艺的粉尘浓度与分布:全年各月粉尘浓度、历年粉尘液度的分布等进行了统计,并分析其差异性,提出了降尘措施。     

Improving GERB scene identification using SEVIRI: Infrared dust detection strategy

The combination of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) and the Geostationary Earth Radiation Budget (GERB) instruments on Meteosat-8 provides a powerful new tool for detecting aerosols and estimating their radiative effect at high temporal and spatial resolution. However, at present no specific aerosol treatment is performed in the GERB processing chain, severely limiting the use of the data for aerosol studies. A particular problem relates to the misidentification of Saharan dust outbreaks as cloud which can bias the shortwave and longwave fluxes. In this paper an algorithm is developed which employs multiple-linear regression, using information from selected thermal infrared SEVIRI channels, to detect dust aerosol over ocean and provide an estimate of the optical depth at 0.55 μm (τ₀₅₅). To test the performance of the algorithm, it has been applied to a number of dust events observed by SEVIRI during March and June 2004. The results are compared to co-located MODIS observations taken from the Terra and Aqua platforms, and ground based observations from the Cape Verde AERONET site. In terms of detection capability, employing the algorithm results in a notable improvement in the routine GERB scene identification. Locations identified by MODIS as being likely to be dust contaminated were originally classified as cloud in over 99.5% of the cases studied. With the application of the detection algorithm approximately 60-70% of these points are identified as dusty depending on the dust model employed. The algorithm is also capable of detecting dust in regions and at times which would be excluded when using shortwave observations, due for example to the presence of sun-glint, or through the night. We further investigate whether the algorithm is capable of generating useful information concerning the aerosol loading. Comparisons with co-located retrievals from the SEVIRI 0.6 μm solar reflectance band observations show a level of agreement consistent with that expected from the simulations, with rms differences of between 0.5 and 0.8, and a mean bias ranging from − 0.5 to 0.3 dependent on the dust representation employed in the algorithm. Temporally resolved comparisons with observations from the Capo Verde AERONET site through the months of March and June reinforce these findings, but also indicate that the algorithm is capable of discerning the diurnal pattern in aerosol loading. The algorithm has now been incorporated within the routine GERB processing in detection mode, and will be used to provide an experimental aerosol product for assessment by the scientific community.     

汞齐锌粉在KOH溶液中的电化学行为

本文通过对碱性电池用DCF Zn—Hg锌粉进行化学分析,测定不同颗粒、不同温度下该锌粉在9MKOH溶液中的析气量,分析碱液中ZnO浓度对析气量和电极电位的影响,研究了汞齐锌粉在碱液中的电化学行为,找到一些降低汞齐锌粉析氢速率的规律。     

2号高炉干法除尘系统集中卸灰改造

针对炼铁厂2号高炉干法除尘系统加湿卸灰所带来的二次扬尘现象，提出了集中卸灰改造的方案，并对改造方案的可行性和改造费用情况作了探讨，同时阐述了改造的实施过程和改造后的操作要求。     

薄膜滤料在城市生活垃圾发电厂烟气净化系统中的应用

文章介绍了一种用于城市生活垃圾电站除尘器中使用滤料它有较好的清灰效果， 使用寿命长，有较高的经济效益和社会效益。