Dust Transport and Processing in Centrifugally Driven Protoplanetary Disk Winds

Context. When and where planetesimals form in a protoplanetary disk are highly debated questions. Streaming instability is considered the most promising mechanism, but the conditions for its onset are stringent. Disk studies show that the planet forming region is not turbulent because of the lack of ionization forming possibly dead zones (DZs). Aims. We investigate planetesimal formation in an evolving disk, including the DZ and thermal evolution. Methods. We used a 1D time-evolving stratified disk model with composite chemistry grains, gas and dust transport, and dust growth. Results. Accretion of planetesimals always develops in the DZ around the snow line, due to a combination of water recondensation and creation of dust traps caused by viscosity variations close to the DZ. The width of the planetesimal forming region depends on the disk metallicity. For Z = Z⊙, planetesimals form in a ring of about 1 au width, while for Z > 1.2 Z⊙ planetesimals form from the snow line up to the outer edge of the DZ ≃ 20 au. The efficiency of planetesimal formation in a disk with a DZ is due to the very low effective turbulence in the DZ and to the efficient piling up of material coming from farther away; this material accumulates in region of positive pressure gradients forming a dust trap due to viscosity variations. For Z = Z⊙ the disk is always dominated in terms of mass by pebbles, while for Z > 1.2 Z⊙ planetesimals are always more abundant than pebbles. If it is assumed that silicate dust is sticky and grows up to impact velocities ~10 m s−1, then planetesimals can form down to 0.1 au (close to the inner edge of the DZ). In conclusion the DZ seems to be a sweet spot for the formation of planetesimals: wide scale planetesimal formation is possible for Z > 1.2 Z⊙. If hot silicate dust is as sticky as ice, then it is also possible to form planetesimals well inside the snow line.

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EFFECT OF DIFFERENT DOSES OF PREDNISOLONE AND ADRENOCORTICOTROPHIC HORMONE (ACTH) ON LYMPHATIC LUNG CLEARANCE AND ON EXPERIMENTAL SILICOSIS

Acta Endocrinologica ◽

10.1530/acta.0.0630325 ◽

1970 ◽

Vol 63 (2) ◽

pp. 325-337

Author(s):

Carl-Johan Göthe

Keyword(s):

Lymph Nodes ◽

Lymphatic System ◽

The Body ◽

Lung Weight ◽

Lung Clearance ◽

Dust Transport ◽

Fine Particulate ◽

Quartz Dust ◽

Different Doses ◽

Stimulation Of

ABSTRACT The effect of three doses of prednisolone and ACTH respectively on the weight of the body, the lungs and the hilar lymph nodes was studied on rats killed one month after the intratracheal (i.t.) injection of 50 mg of fine-particulate quartz. The prednisolone was administered via the drinking water, and the ACTH was injected intraperitoneally during the period between the i.t. injection of quartz dust and the killing of the animals. Prednisolone causes the rats to become cachectic and reduces the weight of the hilar lymph nodes. It also retards the transport of quartz dust from the lungs via the lymphatics. All these effects increase with increasing doses of prednisolone. However, its effect on the lung weight is insignificant. ACTH does not affect the body weight, but retards the weight increase of the lungs and the hilar lymph nodes. These effects increase with increasing doses of ACTH, and seem to be connected with an ability of ACTH to promote the clearance of quartz dust from the lungs and hilar lymph nodes. The method used, however, does not make it possible to differentiate quantitatively between any ACTH effects on the bronchogenie and lymphatic lung-clearance mechanisms. Available data, however, indicate that the stimulation of the dust transport from the lungs and hilar lymph nodes is, at least to some extent, related to the lymphatic system.

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Numerical Modeling of Dust Transport Around Moving Vehicles in Unsteady Atmospheric Boundary Layer Using Precursor Simulation

AIAA Scitech 2021 Forum ◽

10.2514/6.2021-1541 ◽

2021 ◽

Author(s):

Xiaoling Tong

Keyword(s):

Boundary Layer ◽

Numerical Modeling ◽

Atmospheric Boundary Layer ◽

Dust Transport ◽

Moving Vehicles

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Impact of dust and sand storms on the aviation operation and assessment of conditions for their occurrence at aerodromes in European Russia

Hydrometeorological research and forecasting ◽

10.37162/2618-9631-2020-4-78-95 ◽

2020 ◽

Vol 4 ◽

pp. 78-95

Author(s):

A.R. Ivanova ◽

◽

E.N. Skriptunova ◽

N.I. Komasko ◽

A.A. Zavialova ◽

...

Keyword(s):

Seasonal Variations ◽

Dust Storms ◽

European Russia ◽

Air Transport ◽

Review Of Literature ◽

Dust Transport ◽

Air Masses ◽

The Past ◽

Sand Storm ◽

The Impact

A review of literature on the impact of dust and sand storms on the air transport operation is presented. Observational data on dust storms at the aerodromes of European Russia for the period of 2001-2019 are analyzed. The seasonal variations in dust transport episodes at aerodromes and its relationship with visibility changes are discussed. The characteristics of dusty air masses and advection are given. It is concluded that the frequency of dust transfer episodes for the aerodromes under study has decreased over the past five years, except for Gumrak aerodrome (Volgograd). Keywords: dust storm, sand storm, aviation, visibility, seasonal variations, aerodrome оf European Russia

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A TRANS-TASMAN DUST TRANSPORT EVENT

Weather and Climate ◽

10.2307/44279620 ◽

1984 ◽

Vol 4 (2) ◽

pp. 42 ◽

Cited By ~ 17

Author(s):

Collyer ◽

Barnes ◽

Churchman ◽

Clarkson ◽

Steiner

Keyword(s):

Dust Transport

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Numerical analysis of supersonic jet flow and dust transport induced by air ingress in a fusion reactor

Nuclear Science and Techniques ◽

10.1007/s41365-021-00912-z ◽

2021 ◽

Vol 32 (7) ◽

Author(s):

Bu-Er Wang ◽

Shi-Chao Zhang ◽

Zhen Wang ◽

Jiang-Tao Jia ◽

Zhi-Bin Chen

Keyword(s):

Numerical Analysis ◽

Fusion Reactor ◽

Supersonic Jet ◽

Jet Flow ◽

Dust Transport ◽

Air Ingress

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Saharan dust and giant quartz particle transport towards Iceland

Scientific Reports ◽

10.1038/s41598-021-91481-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

György Varga ◽

Pavla Dagsson-Walhauserová ◽

Fruzsina Gresina ◽

Agusta Helgadottir

Keyword(s):

Numerical Models ◽

Saharan Dust ◽

Atmospheric Environment ◽

The Arctic ◽

Dust Particles ◽

Atmospheric Flow ◽

Dust Transport ◽

Strong Winds ◽

Dust Events ◽

Local Dust

AbstractMineral dust emissions from Saharan sources have an impact on the atmospheric environment and sedimentary units in distant regions. Here, we present the first systematic observations of long-range Saharan dust transport towards Iceland. Fifteen Saharan dust episodes were identified to have occurred between 2008 and 2020 based on aerosol optical depth data, backward trajectories and numerical models. Icelandic samples from the local dust sources were compared with deposited dust from two severe Saharan dust events in terms of their granulometric and mineralogical characteristics. The episodes were associated with enhanced meridional atmospheric flow patterns driven by unusual meandering jets. Strong winds were able to carry large Saharan quartz particles (> 100 µm) towards Iceland. Our results confirm the atmospheric pathways of Saharan dust towards the Arctic, and identify new northward meridional long-ranged transport of giant dust particles from the Sahara, including the first evidence of their deposition in Iceland as previously predicted by models.

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Interaction of solid bodies with atmospheres of protoplanets

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319001996 ◽

2018 ◽

Vol 14 (S345) ◽

pp. 351-352

Author(s):

Ernst A. Dorfi ◽

Florian Ragossnig

Keyword(s):

Kinetic Energy ◽

Physical Properties ◽

Planet Formation ◽

Frictional Heating ◽

Protoplanetary Disk ◽

Small Bodies ◽

Early Stages ◽

Break Up ◽

Solid Bodies ◽

Stellar Source

AbstractDuring the early stages of planet formation accretion of small bodies add mass to the planet and deposit their energy kinetic energy. Caused by frictional heating and/or large stagnation pressures within the dense and extended atmospheres most of the in-falling bodies get destroyed by melting or break-up before they impact on the planet’s surface. The energy is added to the atmospheric layers rather than heating the planet directly. These processes can significantly alter the physical properties of protoplanets before they are exposed with their primordial atmospheres to the early stellar source when the protoplanetary disk becomes evaporated.

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