Oxidation gradients in metamorphosed non-carbonatic manganese formations

This paper aims to ascertain the degree of equilibrium attained with respect to oxygen during metamorphism of non-carbonatic manganiferous sediments and the nature of mobility of oxygen in rocks of adjacent beds by measuring the composition of coexisting phases. Through algebraic analysis of the relevant phase equilibria, a difference of ≃17 kcal in in rocks of adjacent beds is obtained. This confirms the immobile nature of oxygen during metamorphism of manganiferous sediments.     

Thermoluminescence and optically stimulated luminescence signals from volcanic ash: History of volcanism in Barren Island,Andaman Sea

The results of experiments which characterise the optically stimulated luminescence (OSL) signals of an ash sample (BI07-TL-05) from Barren Island are presented. The infrared stimulated luminescence signal decreases to 5% of its initial value when preheated at 150 °C for 10 s, suggesting that the infrared stimulated luminescence signal associated with the 290–390 nm emission in this sample arises from a single trap evicted by heating to 150 °C. The post-IR blue stimulated luminescence emission has greater thermal stability and arises from traps which are emptied by heating to temperatures between 120 °C and 240 °C. Dose recovery experiments demonstrate that a laboratory dose can be reliably determined to within 5% for the post-IR blue stimulated luminescence signal. However, the fading rate for the post-IR blue stimulation is high, and the g-value is estimated to be (9.6 ± 3.5)% per logarithmic decade for BI07-TL-05.     

Shake Table Tests and Numerical Modeling of Liquefaction of Kasai River Sand

As a part of the seismic safety evaluation of several bridges and other hydraulic structures located on Kasai River bed in India, the liquefaction potential of Kasai River sand is studied in 1-g shake table in laboratory and numerically using a commercial software FLAC 2D. The surface settlement, lateral spreading, predominant frequency, amplification of the ground motion and pore water pressure development in Kasai River sand in dry and liquefied states have been studied when subjected to sinusoidal motions of amplitude 0.35 g at a frequency of 2 Hz. The nonlinear curves used to represent shear strain dependency of stiffness and damping ratio of Kasai River sand are obtained from cyclic triaxial tests. Reasonably good agreement between the experimental and the numerical results is observed. It is found that the settlement and lateral spreading for the liquefied sand is 2.60 and 2.50 times than those of the sand in the dry state. The volumetric strain of the liquefied sand is found to be around 4%, which is significantly higher than 1.53% observed in the dry sand. It is observed that the amplification of the peak ground acceleration for the saturated sand is 1.08 and 1.32 times higher than that for the dry sand from theoretical and experimental results, respectively. The shear strain developed in the liquefied sand is 1.17 times more than that for dry sand. The fundamental and higher modal frequencies of dry sand are found to be 1.13, 1.117 and 1.119 times more than those for the saturated sand, respectively.     

Nature and profile distribution of iron and aluminum in relation to pedogenic processes in some soils developed under tropical environment in India

Different extractants were used to determine various forms of Fe and Al in three soil profiles developed under a tropical environment in India. The average contents of Fe and Al, extracted by different extracting reagents were found to be in descending order, as follows:

Long-Period Oscillations in Polar Plumes as Observed by cds on Soho

We examine spectral time series of the transition region line Ov 629Å, observed with the Coronal Diagnostic Spectrometer (CDS) on the SOHO spacecraft in July 1997. Both Fourier and wavelet transforms have been applied independently to the analysis of plume oscillations in order to find the most reliable periods. The wavelet analysis allows us to derive the duration as well as the periods of the oscillations. Our observations indicate the presence of compressional waves with periods of 10–25 min. We have also detected a 11±1 min periodicity in the network regions of the north polar coronal hole. The waves are produced in short bursts with coherence times of about 30 min. We interpret these oscillations as outward propagating slow magneto-acoustic waves, which may contribute significantly to the heating of the lower corona by compressive dissipation and which may also provide enough energy flux for the acceleration of the fast solar wind. The data support the idea that the same driver is responsible for the network and plume oscillations with the network providing the magnetic channel through which the waves propagate upwards from the lower atmosphere to the plumes.     

Polar Plumes and Inter-plume regions as observed by SUMER on SOHO

We present observations of Ovi 1032 Å line profiles obtained with the SUMER instrument on SOHO extending from the solar disk to 1.5 R above the limb in the north polar coronal hole. Variations of the intensity and linewidth in the polar plume and inter-plume regions are investigated. We find an anti-correlation between the intensity and the linewidth in the plume and inter-plume regions with detailed plume structures been seen out to 1.5 R . Possible implications regarding the magnetic topologies of these two regions and related heating mechanisms are discussed. The Ovi linewidth measurements are combined with UVCS output to provide an overview of its variations with height extending up to 3.5 R . We find a linear increase of the linewidth from 1 to 1.2 R , then a plateau followed by a sharp increase around 1.5 R .     

Some cylindrically-symmetric cosmological models in general relativity representing viscous fluid and perfect fluid with heat conduction

The paper considers inhomogeneous space-times admitting a two-parameter group of motions and satisfying Einstein's field equations for viscous fluid and perfect fluid with heat conduction. Some homogenous solutions representing viscous fluid have also been obtained for which the free-gravitational field is of the magnetic type. Various physical and kinematical properties have been discussed.     

On comparative probabilities for normal confidence intervals by pearson's Types III and VII, and the Edgeworth series models for biotite data

Biotite crystals were counted in standard thin sections which originated from the diamond drill core of the mafic norite formation at Strathcona mine, Sudbury Nickel Irruptive. Pearson's method of moments is suitable to fit Types III and VII to the biotite data and its log ₁₀ transformation values, as the number of samples (thin sections)is large (351).Based on the two models and the Edgeworth series (utilizing the log ₁₀ data)probability values p,that biotite occurrences lie in the interval mean ± Z standard deviations is derived. Results are compared with the usual normal probability values p_Z corresponding to Zand it is shown that the Edgeworth series generated the largest pvalues for intervals when p_Z values are large; for intermediate or lower p_Z s. Types VII and III models produced larger ps, relative to the Normal and the Edgeworth series.