Aeolian Changes at the Insight Landing Site on Mars: Multi-instrument Observations

2020 ◽  
Author(s):  
Constantinos Charalambous ◽  
Mariah Baker ◽  
Matthew Golombek ◽  
John McClean ◽  
Tom Pike ◽  
...  
Keyword(s):  
Heat Transport ◽  
Local Time ◽  
Particle Motion ◽  
Landing Site ◽  
Atmospheric Conditions ◽  
Simultaneous Measurements ◽  
Aeolian Activity ◽  
Wind Activity ◽  
Convective Vortices ◽  
Instrument Package

<p>The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in western Elysium Planitia on November 26, 2018. Because of its stationary position and a multi-instrument package, InSight offers the unique opportunity of detecting changes induced by aeolian activity and constraining the atmospheric conditions responsible for particle motion.</p><p>In this work, we present the most significant changes from aeolian activity as detected by the InSight lander during its first 400 Martian days of operations. We will show that particle entrainment by wind activity around InSight is a subtle process and report simultaneous measurements observed across multiple instruments. The changes observed are episodic and are seen correlated with excursions in both seismic and magnetic signals, which will be discussed further. Our observations show that all aeolian movements are consistent with the passage of deep convective vortices between noon to 3 pm local time. These vortices may be the primary initiators for aeolian transportation at InSight, inducing episodic particulate motion of grains up to 3 mm in diameter.</p>

scholarly journals Convective vortices and dust devils at the Phoenix Mars mission landing site

2010 ◽  
Vol 115 ◽  
Author(s):  
M. D. Ellehoj ◽  
H. P. Gunnlaugsson ◽  
P. A. Taylor ◽  
H. Kahanpää ◽  
K. M. Bean ◽  
...  
Keyword(s):  
Landing Site ◽  
Dust Devils ◽  
Mars Mission ◽  
Convective Vortices ◽  
The Phoenix

The Effect of Noncondensables on the Buoyancy-Thermocapillary Convection in Confined and Volatile Fluids

2014 ◽  
Author(s):  
Tongran Qin ◽  
Minami Yoda ◽  
Roman O. Grigoriev
Keyword(s):  
Phase Change ◽  
Numerical Simulations ◽  
Heat Transport ◽  
Flow Structure ◽  
Thermocapillary Convection ◽  
Transport Model ◽  
Atmospheric Conditions ◽  
Flow Speeds ◽  
Convection Patterns ◽  
Volatile Liquids

Convection in confined layers of volatile liquids has been studied extensively under atmospheric conditions. Recent experimental results [1] have shown that removing most of the air from a sealed cavity significantly alters the flow structure and, in particular, suppresses transitions between the different convection patterns found at atmospheric conditions. Yet, at the same time, this has almost no effect on the flow speeds in the liquid layer. To understand these results, we have formulated and numerically implemented a detailed transport model that accounts for mass and heat transport in both phases as well as the phase change at the interface. Surprisingly, the numerical simulations show that noncondensables have a large effect on buoyancy-thermocapillary flow at concentrations even as low as 1%, i.e., much lower than those achieved in experiment.

scholarly journals Vortex‐dominated aeolian activity at InSight's landing site, Part 1: Multi‐instrument Observations, Analysis and Implications

2021 ◽  
Author(s):  
C. Charalambous ◽  
B. McClean J. ◽  
M. Baker ◽  
W. T. Pike ◽  
M. Golombek ◽  
...  
Keyword(s):  
Landing Site ◽  
Aeolian Activity

scholarly journals Convective vortices and dust devils at the MSL landing site: Annual variability

2016 ◽  
Vol 121 (8) ◽  
pp. 1514-1549 ◽  
Author(s):  
H. Kahanpää ◽  
C. Newman ◽  
J. Moores ◽  
M.-P. Zorzano ◽  
J. Martín-Torres ◽  
...  
Keyword(s):  
Landing Site ◽  
Dust Devils ◽  
Annual Variability ◽  
Convective Vortices

scholarly journals Experimental Validation of Heat Transport Modelling in Large Solar Thermal Plants

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2343
Author(s):  
Kevin Sartor ◽  
Rémi Dickes
Keyword(s):  
Heat Transport ◽  
District Heating ◽  
Solar Thermal ◽  
Computational Time ◽  
Outlet Temperature ◽  
Atmospheric Conditions ◽  
Present Contribution ◽  
Transport Modelling ◽  
Thermal Plant ◽  
Time Required

Solar thermal plants are often considered as a convenient and environmentally friendly way to supply heat to buildings or low temperature industrial processes. Some modelling techniques are required to assess the dynamic behaviour of solar thermal plants in order to control them correctly. This aspect is reinforced while large plants are considered. Indeed, some atmospheric conditions, such as local clouds, could have significant influence on the outlet temperature of the solar field. A common modelling approach to assess the heat transport in pipes is the one-dimensional finite volume method. However, previous work shows limitations in the assessment of the temperatures and in the computational time required for simulating large pipe networks. In this contribution, a previous alternative method developed and validated in a district heating network is used and extended to a solar thermal plant considering the thermal solar gain and the inertia of the pipes. The present contribution intends to experimentally validate this model on an existing solar plant facility available at the Plataforma Solar de Almeria in Spain.

scholarly journals Multi-model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
C. E. Newman ◽  
M. de la Torre Juárez ◽  
J. Pla-García ◽  
R. J. Wilson ◽  
S. R. Lewis ◽  
...  
Keyword(s):  
Landing Site ◽  
Atmospheric Temperature ◽  
Sand Transport ◽  
Maximum Pressure ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Gale Crater ◽  
Wind Speeds ◽  
Global Circulation ◽  
Aeolian Activity

AbstractNine simulations are used to predict the meteorology and aeolian activity of the Mars 2020 landing site region. Predicted seasonal variations of pressure and surface and atmospheric temperature generally agree. Minimum and maximum pressure is predicted at $\text{Ls}\sim 145^{\circ}$ Ls ∼ 145 ∘ and $250^{\circ}$ 250 ∘ , respectively. Maximum and minimum surface and atmospheric temperature are predicted at $\text{Ls}\sim 180^{\circ}$ Ls ∼ 180 ∘ and $270^{\circ}$ 270 ∘ , respectively; i.e., are warmest at northern fall equinox not summer solstice. Daily pressure cycles vary more between simulations, possibly due to differences in atmospheric dust distributions. Jezero crater sits inside and close to the NW rim of the huge Isidis basin, whose daytime upslope (∼east-southeasterly) and nighttime downslope (∼northwesterly) winds are predicted to dominate except around summer solstice, when the global circulation produces more southerly wind directions. Wind predictions vary hugely, with annual maximum speeds varying from 11 to $19~\text{ms}^{-1}$ 19 ms − 1 and daily mean wind speeds peaking in the first half of summer for most simulations but in the second half of the year for two. Most simulations predict net annual sand transport toward the WNW, which is generally consistent with aeolian observations, and peak sand fluxes in the first half of summer, with the weakest fluxes around winter solstice due to opposition between the global circulation and daytime upslope winds. However, one simulation predicts transport toward the NW, while another predicts fluxes peaking later and transport toward the WSW. Vortex activity is predicted to peak in summer and dip around winter solstice, and to be greater than at InSight and much greater than in Gale crater.

scholarly journals Age of sediments on Danube terraces of the Pest Plain (Hungary) based on optically stimulated luminescence dating of quartz and feldspar

2020 ◽  
Vol 47 (1) ◽  
pp. 171-186
Author(s):  
Edit Thamó-Bozsó ◽  
Gábor Csillag ◽  
Judit Füri ◽  
Attila Nagy ◽  
Árpád Magyari
Keyword(s):  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Strong Wind ◽  
Aeolian Sediments ◽  
Optically Stimulated Luminescence Dating ◽  
Small Streams ◽  
Aeolian Activity ◽  
Wind Activity ◽  
Fluvial Sedimentation ◽  
Late Weichselian

AbstractThe numerical ages available for the sediments on the Danube terraces in the Pest Plain are scarce. In this study, we present quartz OSL and K feldspar post-IR IRSL290 ages for the sandy fluvial, aeolian and slope sediments collected from Danube terraces IIb, III and V.The feldspar post-IR IRSL290 ages without residual dose subtraction are older than the quartz OSL ages, except for one sample, but the two sets of ages are overlapping within one or two sigma errors.In the bleaching experiment under natural sunlight during summer, an unbleachable component ranging from 2.5±0.7 Gy to 5.2±0.3 Gy after 30 h exposure to bright sunshine is observed and it corresponds to 3−8% of the measured K feldspar post-IR IRSL290 equivalent doses. These facts indicate that residual dose subtraction would be necessary before age calculation, in most cases.The saturated fluvial gravelly sand of terrace V of the Danube is older than ~ 296 ka based on feldspar post-IR IRSL290 measurements. This age does not contradict the traditional terrace chronology and the earlier published age data of this terrace. The other studied sediments on the surface of the terraces V, III and IIb deposited much later than the formation of these terraces. They infer aeolian activity and fluvial sedimentation of small streams during the MIS 3 and MIS 2 periods. The age of the dated dune sands with coeval aeolian sediments in Hungary indicate the cold and dry periods with strong wind activity of the Late Weichselian.

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

1996 ◽  
Vol 54 ◽  
pp. 218-219
Author(s):  
H. S. Kim ◽  
R. U. Lee
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Surface Preparation ◽  
Optical Microscope ◽  
Heating Element ◽  
Incomplete Fusion ◽  
Atmospheric Conditions ◽  
Leak Test ◽  
High Temperature Side ◽  
Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 510-511 ◽  
Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann
Keyword(s):  
Heavy Metal ◽  
High Resolution ◽  
Freeze Drying ◽  
Atmospheric Conditions ◽  
Vacuum Equipment ◽  
Transmission Electron ◽  
Gas Atmosphere ◽  
Gas Molecules ◽  
Residual Gas ◽  
Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

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