Diffuse X-ray background measurements in the energy range 2–18 keV

Rocket measurements, of the diffuse X-ray background in the energy range 2–18 keV, conducted from Thumba Equatorial Rocket Launching Station (TERLS), India, are presented. The estimates of the cosmic background are derived by the method which employs the Earth and its atmosphere as a shutter to intercept the celestial X-rays. The results are shown to be consistent with a power law photon spectrum.13.6 _–3.3 ^+4.3 E ^{–1.73±0.15} photons/cm²-sec-keV-ster the spectrum being much flatter than that observed at higher energies.     

Major Element, REE, and Other Trace Element Behavior in Amphibolite Weathering under Semiarid Conditions in Southern India

A body of komatiitic amphibolite, an enclave within the Archean high-grade orthogneisses in southern India, shows mild chemical weathering under semiarid conditions. Along fractures, chemical weathering has advanced (Chemical Index of Alteration &sqbl0;CIA&sqbr0;=53; CIA of fresh rock approximately 26) to the extent that secondary Mg-Fe-Al clay minerals have formed and the rock has turned brownish red, soft, and fine grained. The weathering process has resulted in the mobilization and redistribution of the so-called immobile elements Fe, Al, Ti, and REE effected by the nature of secondary mineral formation (talc vs. aluminous clay minerals) and also possibly by soil microbes. In the initial stages of secondary mineral formation, there is a small loss of Fe, Al, and REE (noticeably Eu). However, in the fracture zone as well as in the incipiently altered zone, there is significant REE enrichment, probably affected by a different precipitation mechanism. Mobilized REE may have come from a minor alteration of clinopyroxene.     

Origin of the pyrophyllite-diaspore deposits of the Bundelkhand Complex,Central India

Twenty three samples from the pyrophyllite-diaspore deposits have been investigated by x-ray diffraction and geochemical methods. The mineral assemblages belong to the K₂O-Al₂O₃-SiO₂-H₂O system. Higher concentrations of Ti, Cr and Zr in the deposits as compared with the associated granites and gneisses suggest their laterite type parentage. Existing mineral assemblages are a result of low grade metamorphism (up to about 350°C) of the primary residual deposits containing a kaolinite - diaspore - quartz assemblage.     

Rapid computation of magnetic anomalies and demagnetization effects caused by bodies of arbitrary shape

Summary With the aid of formulae derived for the field caused by a finite rectangular prism, a machine method is developed for rapid computation of magnetic anomalies due to a body of any shape. Conversely, the method could be utilised for determination of the magnetization vector from the observed anomalies. An example is given to demonstrate the applicability, accuracy and speed of the method. The method is shown to be suitable also for the evaluation of magnetic terrain effects.In addition, a new method is presented which enables high speed calculation of demagnetization effect caused by a body of arbitrary shape where the magnetization in general may be inhomogeneous. Applicability and accuracy of the method are discussed. The method is applied to study the effect of susceptibility on inhomogeneity of the induced magnetization in a cube specimen.For a body of any shape with low susceptibility, a new concept of average demagnetization factor is introduced. Average demagnetization factors so calculated for a cylindrical specimen are tabulated.

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Zusammenfassung Unter Anwendung der Formeln für das Feld eines Quaders wird eine Methode entwickelt um die durch einen Körper beliebiger Form erzeugten magnetischen Anomalien mit Hilfe eines Rechenautomaten zu berechnen. Umgekehrt kann die Methode verwendet werden, um aus den beobachteten Anomalien den Magnetisierungsvektor zu bestimmen. An einem Beispiel wird die Anwendbarkeit, die Genauigkeit und die Schnelligkeit der Methode erläutert. Die Methode kann auch für die Berechnung von magnetischen Terraineffekten verwendet werden.Zudem wird eine neue Methode dargelegt, welche eine rasche Berechnung des Entmagnetisierungseffektes eines Körpers beliebiger Gestalt und inhomogener Magnetisierung ermöglicht. Anwendbarkeit und Genauigkeit der Methode werden besprochen. Die Methode wurde verwendet, um den Einfluss der Suszeptibilität auf die Inhomogenität der induzierten Magnetisierung in einem Würfel zu untersuchen.Für Körper beliebiger Form mit kleiner Suszeptibilität wls neuer Begriff der mittlere Entmagnetisierungsfaktor eingeführt. Mittlere Entmagnetisierungsfaktoren für eine zylindrische Probe werden tabelliert.

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Part I of the dissertation Theretical study of the magnetic attraction due to rock bodies and experimental investigation of the stability of rock magnetism submitted to the Swiss Federal Institute of Technology (ETH), Zurich, for the degree of Doctor of Natural Sciences.     

Velocity of ground water percolation at Indaram, Godavari sub-basin, India

We present values of velocity of ground water percolation (Vg) over large depth intervals, varying from shallow to deeper depths in Indaram area of Godavari sub-basin. The velocities have been estimated using available measured geothermal data. Sub-surface temperatures were measured in seven boreholes. Terrestrial heat flow values are calculated using temperature data and measured values of thermal conductivity of core samples. The results show that Vg is ～3.4 ×10^?7 cm /sec in the top layers (70–150 m) and decreases to ～0.04×10^?7 cm/sec in the deeper levels around 350 m depth and becomes negligibly small thereafter, thereby, indicating that the overall permeability of the sub-surface layers, due to the occurrence of successions of permeable, semi-permeable layers gets reduced to more or less zero at depths around 350 m. The value of Thermal Peclet Number, which is the ratio of the heat transfer through convection to that through conduction, naturally becomes negligible around this depth in the area. The observed consistency of the magnitude of heat flow through various deep sections is a clear indicator that water percolation is practically reduced to zero at depths around 320–400 m and that conduction is the dominant mechanism of heat transfer below the inferred depth section, while the upper layers are dominated by recharge at various depths by near surface water from streams at Indaram.     

Nonlinear electrostatic drift Kelvin-Helmholtz instability

Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves and the nonlinear behaviour is governed by the nonlinear Burger's equation.     

Monitoring litter interception of rainfall using leaf wetness sensor under controlled and field conditions

Leaf litter interception of water is an integral component of the water budget for some vegetated ecosystems. However, loss of rainfall to litter receives considerably less attention than canopy interception due to lack of suitable sensors to measure changes in litter water content. In this study, a commercially available leaf wetness sensor was calibrated to the gravimetric water content of eastern redcedar (Juniperus virginiana ) litter and used to estimate litter interception in a subhumid eastern redcedar woodland in north‐central Oklahoma. Under controlled laboratory conditions, a strong positive correlation between the leaf wetness sensor output voltage (mV) and measured gravimetric litter water content (? _g) was determined: ? _g = (.0009 × mV²) ? (0.14 × mV) ? 11.41 (R ² = .94, p  < .0001). This relationship was validated with field sampling and the output voltage (mV) accounted for 48% of the observed variance in the measured water content. The maximum and minimum interception storage capacity ranged between 1.16 and 12.04 and 1.12 and 9.62 mm, respectively. The maximum and minimum amount of intercepted rain was positively correlated to rainfall amount and intensity. The continuous field measurements demonstrated that eastern redcedar litter intercepted approximately 8% of the gross rainfall that fell between December 16, 2014 and May 31, 2015. Therefore, rainfall loss to litter can constitute a substantial component of the annual water budget. Long‐term in situ measurement of litter interception loss is necessary to gain a better estimate of water availability for streamflow and recharge. This is critical to manage water resources in the south‐central Great Plains, USA where grasslands are rapidly being transformed to woodland or woody dominated savanna.     

Variations in the Solar Coronal Rotation with Altitude – Revisited

Here we report an in-depth reanalysis of an article by Vats et al. (Astrophys. J. 548, L87, 2001) that was based on measurements of differential rotation with altitude as a function of observing frequencies (as lower and higher frequencies indicate higher and lower heights, respectively) in the solar corona. The radial differential rotation of the solar corona is estimated from daily measurements of the disc-integrated solar radio flux at 11 frequencies: 275, 405, 670, 810, 925, 1080, 1215, 1350, 1620, 1755, and 2800 MHz. We use the same data as were used in Vats et al. (2001), but instead of the twelfth maxima of autocorrelograms used there, we use the first secondary maximum to derive the synodic rotation period. We estimate synodic rotation by Gaussian fit of the first secondary maximum. Vats et al. (2001) reported that the sidereal rotation period increases with increasing frequency. The variation found by them was from 23.6 to 24.15 days in this frequency range, with a difference of only 0.55 days. The present study finds that the sidereal rotation period increases with decreasing frequency. The variation range is from 24.4 to 22.5 days, and the difference is about three times larger (1.9 days). However, both studies give a similar rotation period at 925 MHz. In Vats et al. (2001) the Pearson’s factor with trend line was 0.86, whereas present analysis obtained a \({\sim}\,0.97\) Pearson’s factor with the trend line. Our study shows that the solar corona rotates more slowly at higher altitudes, which contradicts the findings reported in Vats et al. (2001).