نتایج جستجو برای: dust charge variation

تعداد نتایج: 475329  

2009
S. D. Bale

The STEREO/WAVES instrument has detected a very large number of intense voltage pulses. We suggest that these events are produced by impact ionisation of nanoparticles striking the spacecraft at a velocity of the order of magnitude of the solar wind speed. Nanoparticles, which are half-way between micron-sized dust and atomic ions, have such a large charge-to-mass ratio that the electric field ...

Journal: :Astrobiology 2006
Gregory T Delory William M Farrell Sushil K Atreya Nilton O Renno Ah-San Wong Steven A Cummer Davis D Sentman John R Marshall Scot C R Rafkin David C Catling

Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar...

Journal: :The Annals of occupational hygiene 2001
D Fishwick L J Allan A Wright A D Curran

The aim of this preliminary study was to assess exposure to various constituents of the organic dust generated during the processing of hemp in a small group of exposed workers. Airborne levels of inhalable dust, endotoxin and soluble protein, and the respirable, thoracic and inhalable fractions of fungal, bacterial and actinomycete contamination were measured in the personal breathing zone of ...

2017
Sepideh Pakpour ELISABETH BIK Ian M. Gut

(...) we wanted to identify key environmental determinants for the house dust microbiome from an existing collection of spatially (area of Munich, Germany) and temporally (301 days) distributed samples and to determine changes in the community as a function of time. To that end, dust samples that had been collected once from the living room floors of 286 individual households, were profiled for...

2006
GREGORY T. DELORY WILLIAM M. FARRELL SUSHIL K. ATREYA NILTON O. RENNO AH-SAN WONG STEVEN A. CUMMER DAVIS D. SENTMAN JOHN R. MARSHALL

Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or “triboelectricity.” In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar...

2008
W. Barreto

We study spherical, charged and self–similar distributions of matter in the diffusion approximation. We propose a simple, dynamic but physically meaningful solution. For such a solution we obtain a model in which the distribution becomes static and changes to dust. The collapse is halted with damped mass oscillations about the absolute value of the total charge.

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...

2012
Pulkit Agarwal Steven L Girshick

Sectional models of the dynamics of aerosol populations are well established in the aerosol literature but have received relatively less attention in numerical models of dusty plasmas, where most modeling studies have assumed the existence of monodisperse dust particles. In the case of plasmas in which nanoparticles nucleate and grow, significant polydispersity can exist in particle size distri...

2014
Jens M Hohlfeld Katrin Lueer Heike Biller Horst Windt Philipp Badorrek Meike Mueller Holger Ziehr Dietrich Haefner Norbert Krug Wolfgang Koch

Background Efficacy testing of immunotherapy in field studies is often hampered by variation of airborne allergens. Standardized allergen exposure in challenge chamber settings might overcome aforementioned limitations. However, airborne allergens such as house dust mite (HDM) or cat allergen are not available as standardized source material with distinct particle size. Therefore, we developed ...

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