scholarly journals Cold condensation of dust in the ISM

2014 ◽  
Vol 168 ◽  
pp. 449 ◽  
Author(s):  
Gaël Rouillé ◽  
Cornelia Jäger ◽  
Serge A. Krasnokutski ◽  
Melinda Krebsz ◽  
Thomas Henning
Keyword(s):  
Cold Condensation

scholarly journals The Distinction Between Thermal Nonequilibrium and Thermal Instability

Solar Physics ◽  
2019 ◽  
Vol 294 (12) ◽  
Author(s):  
James A. Klimchuk
Keyword(s):  
Large Amplitude ◽  
Thermal Instability ◽  
Mhd Waves ◽  
Accelerated Cooling ◽  
Coronal Loops ◽  
Thermal Nonequilibrium ◽  
Cold Condensation

AbstractFor some forms of steady heating, coronal loops are in a state of thermal nonequilibrium and evolve in a manner that includes accelerated cooling, often resulting in the formation of a cold condensation. This is frequently confused with thermal instability, but the two are in fact fundamentally different. We explain the distinction and discuss situations where they may be interconnected. Large-amplitude perturbations, perhaps associated with MHD waves, likely play a role in explaining phenomena that have been attributed to thermal nonequilibrium but also seem to require cross-field communication.

scholarly journals Atmospheric transport of persistent semi-volatile organic chemicals to the Arctic and cold condensation in the mid-troposphere – Part 2: 3-D modeling of episodic atmospheric transport

2010 ◽  
Vol 10 (15) ◽  
pp. 7315-7324 ◽  
Author(s):  
L. Zhang ◽  
J. Ma ◽  
C. Tian ◽  
Y. Li ◽  
H. Hung
Keyword(s):  
Atmospheric Circulation ◽  
Atmospheric Transport ◽  
The Arctic ◽  
Organic Chemicals ◽  
High Latitudes ◽  
Volatile Organic ◽  
Volatile Organic Chemicals ◽  
Cold Condensation ◽  
Condensation Effect ◽  
Modeling Study

Abstract. Two 3-dimensional global atmospheric transport models for persistent organic pollutants (POPs) have been employed to investigate the association between the large-scale atmospheric motions and poleward transports of persistent semi-volatile organic chemicals (SVOCs). We examine the modeled daily air concentration of α- and γ-hexachlorocyclohexane (HCH) over a period from 1997 through 1999 during which a number of episodic atmospheric transport events were detected in this modeling study. These events provide modeling evidence for improving the interpretation on the cold condensation effect and poleward atmospheric transport of SVOCs in the mid-troposphere. Two episodic transport events of γ-HCH (lindane) to the high Arctic (80–90° N), one from Asian and another from Eurasian sources, are reported in this paper. Both events suggest that the episodic atmospheric transports occurring in the mid-troposphere (e.g. from 3000 m to 5500 m height) are driven by atmospheric horizontal and vertical motions. The association of the transport events with atmospheric circulation is briefly discussed. Strong southerly winds, forced by the evolution of two semi-permanent high pressure systems over mid-high latitudes in the Northern Hemisphere, play an important role in the long-range transport (LRT) of HCHs to the high latitudes from its sources. Being consistent with the cold condensation effect and poleward atmospheric transport in a mean meridional atmospheric circulation simulated by a 2-D atmospheric transport model, as reported by the first part of this study, this modeling study indicates that cold condensation is likely occurring more intensively in the mid-troposphere where rapid declining air temperature results in condensed phase of the chemical over and near its source regions and where stronger winds convey the chemical more rapidly to the polar region during the episodic poleward atmospheric transport events.

SYNTHESIS OF ULTRAFINE/NANOSIZE POWDERS OF IRON OXIDES BY PULSED LASER ABLATION AND COLD CONDENSATION

1996 ◽  
Vol 10 (30) ◽  
pp. 1517-1527 ◽  
Author(s):  
S. R. SHINDE ◽  
A. G. BANPURKAR ◽  
K. P. ADHI ◽  
A. V. LIMAYE ◽  
S. B. OGALE ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excimer Laser Ablation ◽  
Nanosize Particles ◽  
Cold Condensation ◽  
Scanning Electron

Ultrafine/nanosize powders of iron oxide have been synthesized from a sintered α- Fe 2 O 3 target by pulsed excimer laser ablation and cold condensation. The influence of target porosity and temperature of condensation on the formation of nanosize particles has been studied. The nanosize powders have been characterized by X-ray diffraction, Mössbauer spectroscopy, vibrating sample magnetometry and scanning electron microscopy. It is shown that the formation of ultrafine/nanosize particles is strongly governed by the target porosity, whereas, the temperature of condensation, over a range from 27°C to −130°C, does not affect the magnetic properties of the nanoparticles.

scholarly journals Atmospheric transport of persistent semi-volatile organic chemicals to the Arctic and cold condensation at the mid-troposphere – Part 2: 3-D modeling of episodic atmospheric transport

2009 ◽  
Vol 9 (6) ◽  
pp. 26237-26264 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Atmospheric Circulation ◽  
Atmospheric Transport ◽  
The Arctic ◽  
Organic Chemicals ◽  
High Latitudes ◽  
Volatile Organic ◽  
Volatile Organic Chemicals ◽  
Cold Condensation ◽  
Condensation Effect ◽  
Modeling Study

Abstract. Two 3-dimensional global atmospheric transport models for persistent organic pollutants (POPs) have been employed to investigate the association between the large-scale atmospheric motions and poleward transports of persistent semi-volatile organic chemicals (SVOCs). We examine the modeled daily air concentration of α- and γ-hexachlorocyclohexane (HCH) over a period from 1997–1999 during which a number of episodic atmospheric transport events were detected in this modeling study. These events provide modeling evidence for improving the interpretation on the cold condensation effect and poleward atmospheric transport of SVOCs at the mid-troposphere. Two episodic transport events of γ-HCH (lindane) to the high Arctic (80–90° N), one from Asian and another from Eurasian sources, are reported in this paper. The both events suggest that the episodic atmospheric transports occurring at the mid-troposphere (e.g. from 3000–5500 m height) are driven by atmospheric horizontal and vertical motions. The association of the transport events with atmospheric circulation is briefly discussed. Strong southerly winds, forced by the evolution of two semi-permanent high pressure systems over mid-high latitudes in the Northern Hemisphere, play an important role in the long-range transport (LRT) of HCHs to the high latitudes from its sources. Being consistent with the cold condensation effect and poleward atmospheric transport in a mean meridional atmospheric circulation simulated by a 2-D atmospheric transport model, as reported by the first part of this study, this modeling study indicates that cold condensation is likely occurring more intensively at the mid-troposphere where rapid declining air temperature results in condensed phase of the chemical over and near its source regions and where stronger winds convey the chemical more rapidly to the polar region during the episodic poleward atmospheric transport events.

Investigation of the Cold Condensation of Persistent Organic Pollutants with a Global Multimedia Fate Model

2000 ◽  
Vol 34 (9) ◽  
pp. 1842-1850 ◽  
Author(s):  
Martin Scheringer ◽  
Fabio Wegmann ◽  
Kathrin Fenner ◽  
Konrad Hungerbühler
Keyword(s):  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Cold Condensation ◽  
Fate Model

First investigations of mountainous cold condensation effects with the CliMoChem model

2006 ◽  
Vol 63 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Fabio Wegmann ◽  
Martin Scheringer ◽  
Konrad Hungerbühler
Keyword(s):  
Cold Condensation

scholarly journals 2. Meteoritic Magnetism: Implications for Parent Bodies of Origin

1977 ◽  
Vol 39 ◽  
pp. 415-427 ◽  
Author(s):  
A. Brecher
Keyword(s):  
Magnetic Fields ◽  
Parent Body ◽  
Magnetic Data ◽  
Carbonaceous Chondrites ◽  
Mantle Structure ◽  
Ordinary Chondrites ◽  
Wind Fields ◽  
Magnetic Record ◽  
Cold Condensation ◽  
Simple Picture

Recent progress in studying and understanding the magnetic record of meteorites is reviewed. Magnetic data are not compatible with the simple picture of a single planetary parent-body with core-mantle structure and a dynamo-generated magnetic field, as earlier envisaged by Soviet colleagues. The strong preterrestrial magnetization of iron meteorites, previously believed to have been acquired during cooling in parent-body fields of -.6 Oe, has now been shown to be probably a spontaneous moment, directionally controlled by the octahedral Ni-Fe structure. For each class of meteorites, the magnetic record is basically in accord with conclusions based on chemical-mineralogical-petrologic characteristics. For example, the complex remanence of brecciated achondrites bears no record of their primary igneous differentiation, but only of multiple brecciation events. Similarly, the unreilites show the expected magnetic imprint of shock-metamorphism at impact. Although systematic trends were found among ordinary chondrites groups, allowing for a rudimentary magnetic classification, only very few appeared to possess a primordial remanence component, which was used to estimate parent body fields in the range 0.1 = .3 oe. Most ordinary chondrites have been magnetically affected by brecciation at formation (e.g., LL), or by metamorphism within the parent body, or individually - by shock at the breakup of the parent body. Only the carbonaceous chondrites have preserved a clear magnetic record of their formation at low-temperature (T < 500° K), in strong magnetic fields (H ≥ 1 oe). The evidence is compatible with cold condensation and aggregation of component grains either in extended, enhanced solar wind fields, or in cometary magnetic fields.

A simple measure for precautionary assessment of organic chemicals with respect to global cold condensation

2006 ◽  
Vol 194 (1-3) ◽  
pp. 266-273 ◽  
Author(s):  
Ulrich Müller-Herold ◽  
Timo Smieszek ◽  
Philippe Peter ◽  
Martin Scheringer ◽  
Marco Morosini
Keyword(s):  
Organic Chemicals ◽  
Simple Measure ◽  
Cold Condensation

Synthesis of Nanophase TiO2 by Ion Beam Sputtering and Cold Condensation Technique

1998 ◽  
Vol 12 (25) ◽  
pp. 2635-2647 ◽  
Author(s):  
L. V. Saraf ◽  
S. I. Patil ◽  
S. B. Ogale ◽  
S. R. Sainkar ◽  
S. T. Kshirsager
Keyword(s):  
Particle Size ◽  
Ion Beam ◽  
Average Particle Size ◽  
Average Particle ◽  
Ion Beam Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Sputtering ◽  
Cold Condensation ◽  
20 Nm

Nanoparticles of TiO 2 have been synthesized by an ion beam sputtering-cold condensation (IBS-CC) technique. A sintered TiO 2 was sputtered by an ion beam (Kaufman source, 900 eV, Ar+ ions) and the ejected atoms/radicals were made to condense on a Si(l00) substrate held at -50°C. X-ray diffraction data showed that the average particle size in the as-deposited material is about 3.5 ± 1.5 nm. Upon annealing at 600°C for five hours, the average particle size was seen to increase to about 70 ± 10 nm. Further annealing for one hour at 900°C led to increase of average particle size to 200 ± 20 nm. X-ray spectroscopy, Raman spectroscopy and photoluminescence data have been used to reveal the presence and relative concentrations of rutile and anatase phases of TiO 2 in the as-deposited and annealed samples. The IBS-CC method is found to yield a more compact particle size distribution as compared to the method based on Laser Ablation.

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