نتایج جستجو برای: dust density

تعداد نتایج: 448715  

Journal: :desert 0
m.r. ekhtesasi associate professor, yazd university, yazd, iran z. gohari msc. graduate, yazd university, yazd, iran

the aim of this study is to determine the area affected by dust storms in different wind speeds using satelliteimages. in the first step, windy conditions of the sistan plain were analyzed using wind statistics data. next, fivestormy days of zabol city, indicating different wind speeds and horizontal visibilities during those storms, wereselected. then, high temporal resolution modis data was u...

Journal: :desert 2013
m.r. ekhtesasi z. gohari

the aim of this study is to determine the area affected by dust storms in different wind speeds using satelliteimages. in the first step, windy conditions of the sistan plain were analyzed using wind statistics data. next, fivestormy days of zabol city, indicating different wind speeds and horizontal visibilities during those storms, wereselected. then, high temporal resolution modis data was u...

Journal: :فیزیک زمین و فضا 0
علیرضا محمودیان institute of geophysics, university of tehran alireza mohebalhojeh institute of geophysics, university of tehran مجید مزرعه فراهانی institute of geophysics, university of tehran wayne scales the bradley department of electrical and computer engineering,virginia tech, usa

on the source of plasma density and electric field perturbations in pmse and pmwe regionspolar mesospheric summer/winter echoes (pmse/pmwe) are very strong radar echoes produced by ionospheric electron density fluctuations at half the radar wavelength. the main focus of this paper is the altitude range 80 to 90 km in summer and altitude range 65-86 km in winter in the polar mesosphere . this pa...

Hadi Eslami, Hamid Reza Azimzadeh, Mahmoud Taghavi, Mohammad Taghi Ghaneian, Reza Ali Fallahzadeh, Seyed Ali Almodaresi,

 Background: The phenomenon of dust is a serious environmental problem in dry and semi dry regions. It has a destructive effect for the residents of such regions. Over two-thirds of Iran is in areas of dry and semi-dry climate conditions. Methods: In this research, dust fall measurements were taken in 41 stations across Yazd city using a marble dust collector (MDCO) located in diffe...

Journal: :environmental health engineering and management 0
hamid reza azimzadeh department of environmental science, school of natural resources & desert studies, yazd university, yazd, iran reza ali fallahzadeh environmental science and technology research center, department of environmental health engineering, student research committee, shahid sadoughi university of medical sciences, yazd, iran mohammad taghi ghaneian environmental science and technology research center, department of environmental health engineering, shahid sadoughi university of medical sciences, yazd, iran seyed ali almodaresi department of gis & rs, engineering college, islamic azad university, yazd branch, yazd, iran hadi eslami environmental science and technology research center, department of environmental health engineering, student research committee, shahid sadoughi university of medical sciences, yazd, iran mahmoud taghavi

background: the phenomenon of dust is a serious environmental problem in dry and semi dry regions. it has a destructive effect for the residents of such regions. over two-thirds of iran is in areas of dry and semi-dry climate conditions. methods: in this research, dust fall measurements were taken in 41 stations across yazd city using a marble dust collector (mdco) located in different parts of...

Kurosh Javidan Marzieh Ghobakhloo Mohammad Ebrahim Zomorrodian

  Propagation of dust ion acoustic waves in plasmas composed of nonthermal distributed electrons and stationary dust particles is investigated. Nonlinear Schrdinger equation is derived to describe small amplitude waves, using the reduction perturbation technique. Modulation instability of dust ion acoustic waves is analysed for this system. Parametric investigation indicates that growth rate of...

Industrial activities and high traffic density are the most important heavy metal pollution sources in urban areas. Roadside dust created by atmospheric deposition can be one of the best indicators for heavy metal contamination levels. The present study reports the spatial distribution patterns and degree of heavy metal pollution (Cd, Cr, Ni, Pb, Zn, and As) in 50 roadside dust samples from urb...

1998
Frank J. Masci

If the background universe is observed through a significant amount of diffusely distributed foreground dust, then studies at optical wavelengths may be severely biased. Previous studies investigating the effects of foreground dust on background sources assumed dust to be “compactly” distributed, ie. on scales comparable to the visible extent of normal galaxies. We show however that diffuse dus...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2013
R Fisher K Avinash E Thomas R Merlino V Gupta

A surprising observation in dusty plasma experiments is that the dust thermal energy density, P_{d}∝n_{d}T_{d}, is typically much greater than n_{d}T_{n} (where n_{d} and T_{d} are the dust density and temperature, and T_{n} is the neutral temperature), even though the dust particles would be expected to be in thermal equilibrium with the neutrals. We show here, theoretically and experimentally...

2005
Dirk Goossens

Many stone-covered surfaces on Earth are subject to aeolian deposition of atmospheric dust. This study investigates how the deposition of dust is affected when rock fragments become gradually more embedded in the ground or, inversely, become more concentrated on the surface. Experiments were executed in an aeolian dust wind tunnel with eight different types of pebbles. The following parameters ...

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