نتایج جستجو برای: dust density

تعداد نتایج: 448715  

2010
K A Nicoll R G Harrison

Electrification of atmospheric dust influences the coagulation, wet removal and fall speeds of dust particles. Alignment of dust particles can also occur in fair weather atmospheric electrical conditions if the particles are charged. However, very few electrical measurements made in elevated dust layers exist. Balloon-borne charge and particle instrumentation have been used to investigate the e...

2011
A. Mahmoudian W. A. Scales M. J. Kosch A. Senior

The objective of this paper is to study the effect of different plasma and dust parameters on Polar Mesospheric Summer Echoes (PMSE) temporal behavior after turn-on and turn-off of radio wave heating and to use these responses to diagnose the properties of the dust layer. The threshold radar frequency and dust parameters for the enhancement or suppression of radar echoes after radio wave heatin...

2008
T. M. Gledhill M. Takami

The dust shell around the evolved star HD 179821 has been detected in scattered light in near-IR imaging polarimetry observations. Here, we subtract the contribution of the unpolarized stellar light to obtain an intrinsic linear polarization of between 30 and 40 per cent in the shell which seems to increase with radial offset from the star. The J and K band data are modelled using a scattering ...

1997
Andreas A. Berlind A. C. Quillen

We measure the extinction law in a galaxy’s spiral arm and interarm regions using a visual and infrared (BVRJHK) imaging study of the interacting galaxies NGC 2207 and IC 2163. This is an overlapping spiral galaxy pair in which NGC 2207 partially occults IC 2163. This geometry enables us to directly measure the extinction of light from the background galaxy as it passes through the disk of the ...

ژورنال: علوم آب و خاک 2018

Dust particles are suspended particles created from various natural and anthropogenic sources. Dust particles contain toxic metals, such as mercury (Hg), which can have harmful effects on the human health. In this study, to investigate the contamination level of Hg in the street dust in Ahvaz, 95 dust samples were collected from the pavements in the main streets. The concentration of Hg in the ...

2012
R. Das

Both compressive and rarefactive solitons are found to exist in the unmagnetized dusty plasma in presence of electrons’ drift velocity ( e v ). Comparision with the earlier findings shows that the factor which is responsible for the existence both compressive and rarefactive solitons is the electrons’ drift velocity ( e v ) in the plasma. It is observed that the compressive solitons exist for...

1999
Frank J. Masci Rachel L. Webster

We explore the effects of dust in cosmologically distributed intervening galaxies on the high redshift universe using a generalised model where dust content evolves with cosmic time. The absorbing galaxies are modelled as exponential disks which form coevally, maintain a constant space density and evolve in dust content at a rate that is uniform throughout. We find that the inclusion of moderat...

2008
Kaisa E. Mueller Heather R. Jacobson

Fifty-one dense cores associated with water masers were mapped at 350 μm. These cores are very luminous, 10 < Lbol/L⊙ < 10 , indicative of the formation of massive stars. Dust continuum contour maps, radial intensity profiles, and photometry are presented for these sources. The submillimeter dust emission peak is, on average, nearly coincident with the water maser position. The spectral energy ...

2003
Harald Krüger Alexander V. Krivov Miodrag Sremčević Eberhard Grün

Tenuous dust clouds of Jupiter’s Galilean moons Io, Europa, Ganymede and Callisto have been detected with the in-situ dust detector on board the Galileo spacecraft. The majority of the dust particles have been sensed at altitudes below five radii of these lunar-sized satellites. We identify the particles in the dust clouds surrounding the moons by their impact direction, impact velocity, and ma...

2016
Christof Lanzerstorfer

In this paper the influence of the moisture content on the flow characteristics of blast furnace dust is investigated. The flowability of granular material is essential for the design and operation of dust separators, transport equipment and storage silos. Two blast furnace dust samples from different blast furnaces were investigated. The moisture content was adapted for measurement with the sh...

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