Presence Of Dust Clouds Research Articles

Analysis of susceptibility of inflammable tobacco products dust to ignition from a heated surface

In the article was described combustible properties of tobacco product dust. Those properties decide about fire and explosion hazard for dust in layer and in cloud according to PN-EN 50281-2-1:2002 and PN-EN ISO/IEC 80079-20-2. There were determined protection against fire and explosion requirements of buildings structural elements and appliances used in space where dust accumulates. The article also consists safety requirements of using appliances in explosion hazard areas according to PN-EN 60079-14:2014. In the article are presented results of minimal ignition temperature of layer (MITL) and minimal ignition temperature of cloud dust (MTCD) as a function of dust layer thickness of chosen tobacco product and values of maximum acceptable surface temperature (MAST) of machines operating in the presence of dust cloud and chosen dust layer with thickness of 5 and 12.5mm.

Analysis of susceptibility to ignition of dust layer and dust cloud of selected hardened unsaturated polyester resins

In the article there were described combustible properties of selected dust types formed of plastic materials. Those properties decide on fire and explosion hazard for dust in layer and in cloud, according to PN-EN 50281-2-1:2002. The article also consists of safety requirements concerning using appliances in explosion hazard areas, according to PN-EN 50281-1-2:2002. In the article there are presented results of investigations on minimal ignition temperature of layer (MITL) and minimal ignition temperature of dust cloud (MITDC) as a function of dust layer thickness of chosen industry dust with different addition of modification and values of maximum acceptable surface temperature (MAST) of machines operating in the presence of dust cloud and chosen dust layer with thickness of 5 and 12.5 mm.

Glow Discharge Positive Column with Dust Particles in Neon

AbstractExperimental and numerical study of positive column of glow discharge in neon with dust particles is presented. The influence of dust structures on integral parameters was measured and simulated. Spatial distributions of electrons and electric field configuration in presence of dust cloud are represented. The reverse radial electric field direction is shown to appear within the dust cloud at high dust particle concentration. The current‐voltage characteristics of discharge in neon with and without dust particles are represented. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Self-learning classification of radar features for scene understanding

Autonomous driving is a challenging problem in mobile robotics, particularly when the domain is unstructured, as in an outdoor setting. In addition, field scenarios are often characterized by low visibility as well, due to changes in lighting conditions, weather phenomena including fog, rain, snow and hail, or the presence of dust clouds and smoke. Thus, advanced perception systems are primarily required for an off-road robot to sense and understand its environment recognizing artificial and natural structures, topology, vegetation and paths, while ensuring, at the same time, robustness under compromised visibility. In this paper the use of millimeter-wave radar is proposed as a possible solution for all-weather off-road perception. A self-learning approach is developed to train a classifier for radar image interpretation and autonomous navigation. The proposed classifier features two main stages: an adaptive training stage and a classification stage. During the training stage, the system automatically learns to associate the appearance of radar data with class labels. Then, it makes predictions based on past observations. The training set is continuously updated online using the latest radar readings, thus making it feasible to use the system for long range and long duration navigation, over changing environments. Experimental results, obtained with an unmanned ground vehicle operating in a rural environment, are presented to validate this approach. A quantitative comparison with laser data is also included showing good range accuracy and mapping ability as well. Finally, conclusions are drawn on the utility of millimeter-wave radar as a robotic sensor for persistent and accurate perception in natural scenarios.

Evaluation of ultrasonic sensor for variable-rate spray applications

Automatic variable-rate sprayers require accurate measurement of canopy size. An estimate of canopy size is made by measuring the distance to the canopy at several elevations above the ground; an ultrasonic sensor was used to determine canopy distance in this study. It is sometimes necessary to conduct spray operations during harsh operating conditions. In this study ultrasonic sensors were subjected to simulated environmental and operating conditions to determine their durability and accuracy. Conditions tested included exposure to extended cold, outdoor temperatures, cross winds, temperature change, dust clouds, travel speeds and spray cloud effects. The root mean square (RMS) error in a series of measurements of the distance to a simulated plant canopy was used to test for significant difference among treatments. After exposure to outdoor cold conditions for 4 months, the RMS error in distance measured by the ultrasonic sensor increased from 3.31 to 3.55 cm, which was not statistically significant. Neither the presence of dust cloud nor the changes in cross-wind speeds over a range from 1.5–7.5 m/s had significant effects on the mean RMS errors. Varying sensor travel speed from 0.8 to 3.0 m/s had no significant influence on sensor detection distances. Increasing ambient temperature from 16.7 to 41.6 °C reduced the detection distance by 5.0 cm. The physical location of the spray nozzle with respect to the ultrasonic sensor had a significant effect on mean RMS errors. The mean RMS errors of sensor distance measurements ranged from 2.3 to 83.0 cm. The RMS errors could be reduced to acceptable values by proper controlling the sensor/spray nozzles spacing on a sprayer. In addition, multiple-synchronized sensors were tested for their measurement stability and accuracy (due to possible cross-talk errors) when mounted on a prototype sprayer. It was found that isolating the pathway of the ultrasonic wave of each sensor reduced detecting interference between sensors during multiple sensor operation. Test methods presented herein may be useful in the design of standardized testing protocols for field use distance sensors.

First Results from the Space Telescope Imaging Spectrograph: Optical Spectra of Gliese 229B

We report the firstHubble Space TelescopeSpace Telescope Imaging Spectrograph (STIS) CCD spectroscopy of the bona fide brown dwarf Gliese 229B. The optical spectrum shows absorptions of Csi at 8944 Aand water vapor bands at 9300-9600 A ˚. Strong CaH, FeH, TiO, and VO bands observed in late M dwarfs are absent from the spectrum of Gliese 229B. The formation of dust grains may explain the absence of strong atomic lines and molecular bands of these refractory elements. The broad spectral coverage obtained helps resolve current spec- ulations about the presence of dust clouds in the atmosphere of cool brown dwarfs. We find the slope of the STIS/CCD spectrum and the lack of flux detected shortward of 8000 Astrongly supports the presence of dust hazes suspended in the photosphere of Gl 229B rather than a complete settling of the grains to regions below the photosphere. Subject headings: binaries: general — stars: individual (Gl 229B) — stars: low-mass, brown dwarfs

The Population I Content of the Elliptical Companions of M31

Twenty years ago Walter Baade pointed out the remarkable fact that two of the four elliptical galaxy companions of M31 (namely NGC 185 and 205) contained apparent Population I in their central areas, evidenced by the presence of dust clouds and a dozen or so OB stars. I wish to report here on some observations of these stars and absorption regions, made in an attempt to understand the origin of this anomalous material and its relevance, if any, to the pattern of galaxy development.