scholarly journals Determination of the levitation limits of dust particles within the sheath in complex plasma experiments

2012 ◽  
Vol 19 (1) ◽  
pp. 013707 ◽  
Author(s):  
Angela Douglass ◽  
Victor Land ◽  
Ke Qiao ◽  
Lorin Matthews ◽  
Truell Hyde
2021 ◽  
Vol 11 (15) ◽  
pp. 6874
Author(s):  
Miroslava Vandličkova ◽  
Iveta Markova ◽  
Katarina Holla ◽  
Stanislava Gašpercová

The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size <100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).


1966 ◽  
pp. 296-302 ◽  
Author(s):  
A. D. Zimon ◽  
N. I. Dovnar ◽  
G. A. Belkina ◽  
G. V. Nozdrina

Observations of Syncom 2 and Syncom 3 during seven separate periods of free drift have been used in an attempt to find the effective potential at synchronous height. Although the accelerations are well determined near the two longitudes, 180° E and 300° E, where the observations are clustered, the poor distribution in longitude does not permit a satisfactory determination of individual coefficients. It would be particularly valuable to have observations in the region 0 to 40° E or around either of the two stable points near 70° E and 250° E. If there is or has been any significant population of dust particles in distant geocentric orbits, it is likely that a proportion will have been captured in the synchronous resonance, and will have accumulated near the stable positions. It is therefore suggested that it would be worth attempting to observe whether there are clouds of dust particles near the stable longitudes, and in the stable plane for synchronous height.


Author(s):  
Sergey Mineev ◽  
◽  
Oleg Usov ◽  

Purpose. Development of a criterion for compliance with the normative indicator – technically achievable level of dust (TAL) – a safe dose of dust particles that have entered the lungs of the employee for the entire period of retirement. Method. The research was conducted on the basis of standard algebraic analysis of the requirements of regulatory documents. Results. A criterion was obtained for the assessment by the coordinating organizations of the correctness of the mine’s determination of the technically achievable level of dustiness of the TAL. It is not related to the assessment of the perfection of dust control technology, but to the medical requirements for the prevention of employee pneumoconiosis during the entire retirement age of his work in a dusty atmosphere (20 years). The criterion is based on the amount of dust load on the respiratory organs of the underground worker during the shift, month, year and the entire period of his work, regulated by current regulations. Scientific novelty. It consists in the mathematical formalization of an intuitive connection between TAL – the maximum level of dustiness of underground workings during excavation machines, medium-variable dust, which takes into account interruptions in the work of excavation machines, and dust load on the respiratory organs of the worker. Practical meaning. The developed criterion allows to carry out the coordinated policy of the management and trade unions of the coal enterprises, supervisory and coordinating instances in questions of reasonable sufficiency of the planned antidust measures, both at a stage of drawing up of the design documentation, and at coordination of acts of TAL. Key words: dustiness, dust load, respiratory organs, dust excretion, dust suppression.


2019 ◽  
Vol 126 ◽  
pp. 00071
Author(s):  
Anatoly Vasiliev ◽  
Igor Stefanenko ◽  
Valery Azarov ◽  
Denis Nikolenko

The article addresses issues, which are related to the determination of aerodynamic characteristics of dust particles in roadside air areas. Was studied dustiness of Volgograd roadside areas.


1996 ◽  
Vol 150 ◽  
pp. 301-308 ◽  
Author(s):  
A.C. Levasseur-Regourd

AbstractRecent progress has been reported in the determination of the zodiacal thermal emission, brightness and polarization. These results, of interest to estimate the foreground sources in astrophysical observations, do not provide immediately information on the dust distribution, and on its optical and thermal properties. To infer local information about the bulk density, and the physical properties of the dust particles, it is necessary to compare the observations with realistic models or to invert the line-of-sight data. The latter approach typically suggests that the bulk density is (in the symmetry plane) inversely proportional to the solar distance, that the particles are not spheroidal, but rather irregular in shape, that their physical properties change with their distance to the Sun and their orbital inclination, and finally that they do not emit like a blackbody. The heterogeneity noticed in the cloud is due to various sources of dust particles, the size, shape or albedo of which evolve as a function of time, under collision and/or evaporation processes.


2014 ◽  
Vol 80 (6) ◽  
pp. 869-876 ◽  
Author(s):  
Yoshifumi Saitou ◽  
Osamu Ishihara

A collective behavior of dust particles in a complex plasma with a magnetic field (up to 4 kG) is investigated. Dust particles form a dust disk which is rotating in a horizontal plane pushed by ions rotating with the E × B drift as a trigger force. The thickness of the disk is determined by controlling the experimental conditions. The disk rotates in a horizontal plane and forms a two-dimensional thin structure when the pressure pAr is relatively high. The dust particles are ejected from near the disk center and form a rotation in the vertical plane and, hence, forms a helical vortex when the disk is thick for relatively low pAr. The reason the dust disk has the different thickness is due to the neutral pressure. Under a higher (lower) neutral gas pressure, the disk becomes two (three) dimensional due to the influence of the neutral drag force.


2005 ◽  
Vol 12 (9) ◽  
pp. 093503 ◽  
Author(s):  
V. Yaroshenko ◽  
S. Ratynskaia ◽  
S. Khrapak ◽  
M. H. Thoma ◽  
M. Kretschmer ◽  
...  
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