Relative cleanliness as a measure of lunar soil strength

Nelson, John D.; Vey, Eben

doi:10.1029/jb073i012p03747

Cited by 19 publications

(9 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the preparation of the samples used in this study, direct contact with liquid water during grinding was avoided, as this would very likely have caused some change in surface properties due to leaching. However, the powder samples were handled in air of average humidity and several studies have shown that any silicate surface exposed to air of normal humidity will immediately be coated by water molecules, which will not be removed even in vacuum, unless the sample is heated to temperatures far above 100 °C (Kunkel 1950;Nelson and Vey 1968;Zhuravlev 1987;Garofalini 1990; see also Keppler and Rauch 2000;Lathem et al 2011). Measurement of the adsorption of water vapor on silicate glass (Razouk and Salem 1948) show that it can be described by a type II isotherm, very similar in shape to those measured for SO 2 in this study.…”

Section: Sulfur Adsorption In Volcanic Plumesmentioning

confidence: 99%

Adsorption of sulfur dioxide on volcanic ashes

Schmauss

Keppler

2014

American Mineralogist

View full text Add to dashboard Cite

The adsorption of pure sulfur dioxide gas on volcanic ashes has been studied from 0.1 mbar to 1 bar and from -80 to +150 °C. Finely ground synthetic glasses of andesitic, dacitic, and rhyolitic composition served as proxies for fresh natural ash surfaces. Powders from two natural obsidian samples were also studied and yielded results broadly similar to the synthetic model systems. SO 2 adsorption on ash is partially irreversible; it appears that the first layer of SO 2 molecules absorbed on the surface cannot be removed. The pressure and temperature dependence of adsorption can be described by the equation lnc = A T -1 + B lnP + C, where c is the surface concentration of adsorbed SO 2 in mg/m 2 , T is temperature in Kelvin, and P is the partial pressure of SO 2 in mbar. A multiple regression analysis of the experimental data yielded A = 1645, B = 0.29, C = -7.43 for andesite, A = 2140, B = 0.29, C = -9.32 for dacite, and A = 910, B = 0.21, C = -4.48 for rhyolite. These data imply that adsorption strongly decreases with temperature, but only slowly decreases with decreasing partial pressure of SO 2 . Therefore, adsorption primarily occurs in the cool and diluted parts of the volcanic plume. Model calculations show that most of the SO 2 may be removed from the plume, if the initial SO 2 concentration in the volcanic gases is low and the surface area of the ash is high. For high initial SO 2 concentrations, the fraction of SO 2 that is lost by adsorption decreases, since the amount of SO 2 in the gas phase is proportional to the SO 2 partial pressure P, while adsorption is proportional only to P 0.2 -P 0.3 . Adsorption of SO 2 on ash particles may therefore be one reason why the climatic impact of explosive volcanic eruptions does not always scale with total sulfur yield.

show abstract

Section: Sulfur Adsorption In Volcanic Plumesmentioning

confidence: 99%

Adsorption of sulfur dioxide on volcanic ashes

Schmauss

Keppler

2014

American Mineralogist

View full text Add to dashboard Cite

show abstract

“…Direct shear tests were conducted on several soil samples simulating lunar regolith under both Earth's atmospheric and ultrahigh vacuum conditions to quantitatively evaluate the effect of lunar environmental conditions on the properties of the lunar regolith layer. The shear strength of the samples significantly increased under ultrahigh vacuum conditions (Nelson and Vey, 1968). This increase was due mainly to the reduction of the water vapor molecules adsorbed on the particles when exposed to the Earth's atmosphere.…”

Section: Introductionmentioning

confidence: 96%

Cohesion of regolith: Measurements of meteorite powders

Nagaashi

Aoki

Nakamura

2021

Icarus

View full text Add to dashboard Cite

“…The lunar surface is very clean and there are supposed to be no other adsorbed materials except a trace of rare gases. The relative cleanliness [55] has a very pronounced influence on strength because of a dramatic increase in interparticle forces, which may be chiefly vdW type. However, the holding of lunar dust on a steep slope suggests that the major force is greater than the vdW forces.…”

Section: Adhesion and Cohesion Mechanisms Of Lunar Dustmentioning

confidence: 98%

Adhesion and cohesion mechanisms of lunar dust on the moon's surface

Lee

1995

Journal of Adhesion Science and Technology

View full text Add to dashboard Cite

This review is based on many publications from the US and some from the former Soviet Union. It briefly describes the sources of lunar dust. The problems posed to the past Apollo missions are summarized. The physical properties of lunar soils, such as cohesion, angle of repose, angle of friction, and bearing capacity, as reported by scientists from these two nations, are compared. The composition of lunar soils is described in terms of acidic and basic components. Since lunar soils are mainly silicates, we are the first to point out the importance of the Lewis acid-base interaction to the cohesion and adhesion of lunar dust. The adhesion of lunar dust is similar to that of a xerographic developer. For the adhesion between lunar dust and dissimilar materials, both van der Waals and electrostatic interactions can be the driving force, depending on the size of the dust particles. For particles smaller than 50 µm, van der Waals interaction predominates, while for those larger than 50 µm, electrostatic interaction controls. For the electrostatic interaction, lunar dust should charge positively. If lunar dust is pre-charged, e.g. by solar wind, the electrostatic interaction should predominate regardless of the size of the particles. It is important to note that for the electrostatic interaction, both electronic and ionic mechanisms can influence charge exchange. Thus, the Lewis type acid-base interaction can also affect the charge exchange. Experimental work with a simulated lunar dust is recommended for the elucidation of the adhesion and cohesion mechanisms. Before that, all methods of control of lunar dust are, at best, speculative.

show abstract

Relative cleanliness as a measure of lunar soil strength

Cited by 19 publications

References 5 publications

Adsorption of sulfur dioxide on volcanic ashes

Adsorption of sulfur dioxide on volcanic ashes

Cohesion of regolith: Measurements of meteorite powders

Adhesion and cohesion mechanisms of lunar dust on the moon's surface

Contact Info

Product

Resources

About