scholarly journals Lunar Magnetism

1977 ◽  
Vol 4 (1) ◽  
pp. 191-193
Author(s):  
S.K. Runcorn
Keyword(s):  
Remanent Magnetization ◽  
Natural Remanent Magnetization ◽  
Iron Core ◽  
Low Grade ◽  
The Moon ◽  
Magnetic Studies ◽  
Steady Magnetic Field ◽  
The Stability ◽  
Time Of Origin

It was not generally anticipated by lunar scientists that the Moon rocks would prove to possess a natural remanent magnetization because the absence of a present field had already been demonstrated and it was almost universally believed that the Moon did not possess an iron core in which such a field could be generated. Consequently the initial investigation of Apollo 11 rocks was directed towards the use of rock magnetic studies as an adjunct to petrological examination. One of the most notable findings of the Apollo programme was the demonstration of the existence of a natural remanent magnetization (NRM) in Apollo 11 lavas and breccias. Experiments on the stability of the NRM enabled it to be concluded that the rocks were already magnetized when they were on the Moon. This conclusion was soon corroborated by the discovery of the existence of a steady magnetic field at the Apollo 12 site of the magnitude expected from the intensity of the NRM of about 36 γ (in addition to the field fluctuating solar wind. It was reasoned from this early work that the natural remanent magnetization had been acquired at the time of origin of the rocks or at least in their early history and a case was made out that this was a thermoremanent magnetization acquired as the lava flows cooled from magma flowing into the mare basin and as the high grade breccias cooled after the impacts. The origin of the natural remanent magnetization of the low grade breccias is more problematic and the role of other kinds of remanent magnetization processes has been investigated, particularly the effect of shock.

scholarly journals Convection in the Moon

1972 ◽  
Vol 47 ◽  
pp. 377-383
Author(s):  
S. K. Runcorn
Keyword(s):  
Heat Transfer ◽  
Solid State ◽  
Remanent Magnetization ◽  
Second Harmonic ◽  
Crystalline Rocks ◽  
Hydrostatic Equilibrium ◽  
Iron Core ◽  
The Moon ◽  
History Of ◽  
The Moment

It is natural to inquire whether thermal convection is occurring in the Moon through solid state creep processes. The primary evidence is the departure of the Moon from the figure of hydrostatic equilibrium, but certain difficulties in the thermal history of the Moon are eased by assuming heat transfer by convection. If convection exists in the Moon it must have a second harmonic pattern, otherwise the lunar moments of inertia would not differ.Two important predictions of the marginal theory of convection: the existence of a core of radius 0.06–0.3 of the lunar radius (for a second ergee harmonic) and the value of 0.4 for the ratio of the dynamical to surface ellipticities now have support, the latter from the data of the heights of the lunar surface. The former prediction is compatible with the value of the moment of inertia factor now found if the Moon's interior is ‘hot’.Further the existence of a fluid iron core 3400 m.y. ago seems required as a result of the remanent magnetization of the crystalline rocks of the maria basins inferred from the remanent magnetization of the returned Apollo samples and the fields measured by the Apollo 12 and Explorer magnetomers.

New constraints on the role of late Variscan extension in the origin of the Eastern Galicia Magnetic Anomaly (NW Spain)

2020 ◽  
Author(s):  
Puy Ayarza ◽  
Juan José Villalaín ◽  
Jose Ramón Martínez Catalán ◽  
Fernando Alvarez Lobato ◽  
Manuela Durán Oreja ◽  
...  
Keyword(s):  
Magnetic Anomaly ◽  
Remanent Magnetization ◽  
Magnetic Anomalies ◽  
Natural Remanent Magnetization ◽  
Source Rocks ◽  
Magmatic Rocks ◽  
Extensional Tectonic ◽  
Tectonic Window ◽  
Central Iberian Arc

<p><span lang="EN-US">The Eastern Galicia Magnetic Anomaly (EGMA) is one of the most conspicuous and, definitively, the best studied of all the magnetic anomalies in the Central Iberian Arc (CIA). This is probably due to its location, on the thoroughly researched Lugo-Sanabria gneiss dome and to the unique fact that its source rocks crop out in the Xistral Tectonic Window. Multiple studies and models of this anomaly have been carried out in the last 25 years and still, new results keep on shedding more light on its understanding. Rock magnetic analyses, natural remanent magnetization, anisotropy of the magnetic susceptibility and stable isotopes geochemistry carried out on the rocks that produce this anomaly have provided new insights on the processes that led to magnetization and on its age. Results suggest that magnetization of source rocks is a consequence of the increase in oxygen fugacity underwent by metamorphic and magmatic rocks affected by late-Variscan extensional tectonics. Extensional detachments were the pathways that allowed the entrance of fluids that led to syn-tectonic crystallization of magnetite and hematite in S-Type granites. Accordingly, magnetization is not really linked to primary lithologies but mostly to extensional structures. This process took place in the late Carboniferous to earliest Permian, during the Kiaman reverse superchron. Natural remanent magnetization exhibited by hematite-bearing samples confirms the age of the magnetization and adds complexity to the interpretation of the EGMA, where remanence has been often largely ignored or underestimated. Understanding the origin of the EGMA contributes to the interpretation of other anomalies existing in the CIA, also located on thermal domes. Furthermore, it provides new hints to interpret magnetic anomalies located in extensional tectonic contexts worldwide</span></p>

scholarly journals NEW TECHNIQUES FOR SAMPLING AND CONSOLIDATION OF SEDIMENTS: APPLICATION TO BURNT SOILS FROM AN ARCHAEOLOGICAL SITE IN AUSTRIA

2004 ◽  
Vol 36 (3) ◽  
pp. 1129
Author(s):  
E. Aidona ◽  
R. Scholger ◽  
H. J. Mauritsch
Keyword(s):  
Magnetic Susceptibility ◽  
Bronze Age ◽  
Remanent Magnetization ◽  
Archaeological Site ◽  
Natural Remanent Magnetization ◽  
New Techniques ◽  
Stable Component ◽  
History Of ◽  
The Times ◽  
The Stability

An archaeomagnetic study requires samples to be oriented very precisely prior to the removal from the site and to be transported safely since most of the times the collected samples are very soft and fragile. In this study we present new techniques for sampling and consolidation of sediments and unconsolidated soils, which are useful tools for palaeomagnetic and archaeomagnetic investigations. An application of the above techniques has been performed in burnt soils (roastbeds) in an archaeological site near Eisenerz (Austria), which used to be a cooper-smelting place in Bronze Age (around 1450 b.c.) Several roast beds have been collected and consolidated in order to investigate the distribution and the stability of the magnetization of these materials. We obtained around 350 samples and the natural remanent magnetization and the magnetic susceptibility of all these samples have been measured with a 2G squid cryogenetic magnetometer and a GEOFYSIKA KLY-2 susceptibility meter, respectively. Plots of the natural remanent magnetization and magnetic susceptibility versus depth indicate different layers of heating and give some first evidences for the use of these soils during the smelting procedure. Higher values of the intensity of the magnetization as well as of the magnetic susceptibility represent the more intense heating layer. Magnetic cleaning (thermal and Af demagnetization) of pilot samples revealed the presence of a stable component of magnetization. It seems, therefore, that these types of materials are suitable for an archaeomagnetic investigation, since they are able to record and preserve all the necessary magnetic information and provide important knowledge concerning the recent history of the Earth's magnetic field.

Inclinaison magnétique de roches basaltiques de la dorsale est-pacifique à 21°N et validité des critères de polarité

1983 ◽  
Vol 20 (2) ◽  
pp. 322-333 ◽  
Author(s):  
Brigitte Smith
Keyword(s):  
Remanent Magnetization ◽  
Natural Remanent Magnetization ◽  
Mean Value ◽  
Magnetization Direction ◽  
Basaltic Rocks ◽  
Stable Direction ◽  
Normal Polarity ◽  
The Stability

Among the basaltic rocks sampled by submersible or dredged at the East-Pacific Rise axis around 21°N latitude (French–American–Mexican legs CYAMEX and RISE), 22 samples have been selected according to macroscopic, oriented criteria (elongation plane of feeder tubes in sheeted lavas, bubbles and gas cavities, stalactites, septa) from which the polarity of a sample, acquired in situ during its cooling, could be established.The natural remanent magnetization intensity of these generally voluminous samples (up to about 350 cm3) has a mean value of 11.35 ± 2.31 A∙m−1 (10−3 emu∙cm−3); the scatter of the values can be explained by the varying proportion of nonmagnetic material (glass, Mn) in the samples.The magnetic viscosity is always negligible and the stability of the remanent magnetization direction after alternating field demagnetization indicates that the stable direction determined is the direction of the original thermoremanence.Despite the relatively low latitude, which makes the occurrence of negative magnetic inclinations within a normal polarity period (Brunhes, in this case) more probable, no reverse polarity has been found. The mean inclination of the 22 samples is I = +41.8 ± 16.7° and becomes I = +42.2 ± 19.4° if the samples are grouped in 15 pin-point sampling sites; these values are not significantly different from those of the local dipole field, I = ±37.4°, or from those of the actual local field, I ~ +47°, which may be the result of effusions from the youngest lava flows.The scatter of the magnetic inclination values is more tightly bound to the quality of the polarity criteria than to the secular variation of the Earth ' s magnetic field, the latter interfering in only a few cases. It is obvious that the validity of the reorientation depends on (1) the morphological quality of the criteria used: those that are well developed, well represented in the sample, and apparently the most crystallized (glassy criterion has proved to be doubtful), permit a better reorientation of the sample; and (2) the principle of the criterion itself: criteria referring to vertical axes (stalactites) or vertical planes (septa) are more reliable than those based upon the determination of a horizontal plane (elongation plane of tubes in sheeted lavas).It appears from this study that macroscopic polarity criteria may be used in an almost systematic way to find the polarity of an in situ sample.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

The Role of Epicardial Adipose Tissue Lymphocytes in Low-Grade Inflammation and Coronary Artery Disease

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 469-P
Author(s):  
MILOS MRAZ ◽  
ANNA CINKAJZLOVA ◽  
ZDENA LACINOVÁ ◽  
JANA KLOUCKOVA ◽  
HELENA KRATOCHVILOVA ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Adipose Tissue ◽  
Coronary Artery ◽  
Epicardial Adipose Tissue ◽  
Low Grade ◽  
Artery Disease ◽  
Low Grade Inflammation

The Role of Hydrophobicity in the Stability and pH-Switchability of (RXDX)4 and Coumarin-RXDX Conjugate β-Sheets

2020 ◽  
Author(s):  
Ryan Weber ◽  
Martin McCullagh
Keyword(s):  
Biological Imaging ◽  
Ph Sensing ◽  
Hydrophobic Residue ◽  
Ideal Candidate ◽  
Self Assembling ◽  
Sensing Applications ◽  
Β Sheets ◽  
The Stability ◽  
Dynamics Simulations

<p>pH-switchable, self-assembling materials are of interest in biological imaging and sensing applications. Here we propose that combining the pH-switchability of RXDX (X=Ala, Val, Leu, Ile, Phe) peptides and the optical properties of coumarin creates an ideal candidate for these materials. This suggestion is tested with a thorough set of all-atom molecular dynamics simulations. We first investigate the dependence of pH-switchabiliy on the identity of the hydrophobic residue, X, in the bare (RXDX)<sub>4</sub> systems. Increasing the hydrophobicity stabilizes the fiber which, in turn, reduces the pH-switchabilty of the system. This behavior is found to be somewhat transferable to systems in which a single hydrophobic residue is replaced with a coumarin containing amino acid. In this case, conjugates with X=Ala are found to be unstable and both pHs while conjugates with X=Val, Leu, Ile and Phe are found to form stable β-sheets at least at neutral pH. The (RFDF)<sub>4</sub>-coumarin conjugate is found to have the largest relative entropy value of 0.884 +/- 0.001 between neutral and acidic coumarin ordering distributions. Thus, we posit that coumarin-(RFDF)<sub>4</sub> containing peptide sequences are ideal candidates for pH-sensing bioelectronic materials.</p>

Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  
Keyword(s):  
Alkyl Group ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Terminal Alkyne ◽  
Alkyl Aryl ◽  
Metal Metal ◽  
The Stability ◽  
Selective Formation ◽  
Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

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