U234/U238 activity ratios in South Pacific Ocean waters

Analyses of uranium extracted from South Pacific waters by thein-situ extraction method point to a uniform depth independent value of 1·14 ±0 02 for the U²³⁴/U²³⁸ activity ratio. This value is also the same, within one standard deviation, as that determined for the N. Pacific, S. Indian and Atlantic waters.     

Man-made plutonium in freshwater and marine environments

Significant concentrations of plutonium isotopes are found in lake and coastal marine sediments accumulating at rates of 1–5 mm/yr. The activity levels of^{239, 240}Pu range between 0·7–3·3 dpm/g for post 1960 sediments. The measured and the calculated integrated activities of²³⁹Pu in the lake sediments are in agreement. This suggests that plutonium is chemically reactive in freshwater environments and it is removed to sediments from the water column shortly after its injection. A delay of about three years has been observed between the peak of plutonium fallout and its incorporation in the varved sediment from Santa Barbara basin. Based on this observation the mean size of particles transporting plutonium to the basin sediments is estimated to be about three microns. The usefulness of plutonium isotopes as a tracer nuclide for estimating sedimentation rates for the last two decades have been evaluated.     

Radon concentration of air over the Eastern Arabian Sea

The radon concentrations of air samples collected during the South West monsoon period at altitudes up to 4 km over the Arabian Sea at two locations,i.e., 0–50 km and 300–400 km west of Bombay, are reported. Radon was extracted from air, using a simple single stage apparatus. The concentration of radon in the monsoon air mass was found to range around 80–100 dpm/m³ STP, indicative of its recent continental origin. The results suggest that the coastal monsoon air mass, up to 400 km west of Bombay coast, is generally homogeneous and vertically well mixed. During the post-monsoon condition, a strong gradient in the radon concentration in the vertical is observed. The concentration of radon decreases from 157 dpm/m³ at sea level to 35 dpm/m³ at about 3·7 km altitude, suggesting a vertical turbulent diffusion coefficient of ～6×10⁴ cm²/sec. In contrast, the near absence of vertical gradient of radon in the monsoon air mass indicates that the vertical turbulence is much stronger during the monsoon period.     

Uniqueness of the extremal function for thep-capacity of a condenser

The uniqueness of the extremal function for the p-capacity of a condenser is established. Bibliography: 7 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 226, 1996, pp. 228–234.     

Investigations on the multiply charged nuclei of the primary cosmic radiation near the geomagnetic equator using nuclear emulsion

A nuclear emulsion stack was exposed over Hyderabad, India (geomagnetic latitudeλ=7·6° N) under a mean atmospheric depth of 6·8 g./cm.², on 24 March 1960. The relative and absolute intensities of Be and B nuclei and nuclei of charge Z?6 (the S-nuclei) have been determined in this stack. The intensities were extrapolated to the top of the atmosphere using measured fragmentation parameters involved in collisions of cosmic ray nuclei in graphite. The flux values of Be, B and S nuclei at the top of the atmosphere have been determined to be 0·025±0·011, 0·101±0·023 and 1·12±0·10 particles/m.² sec. sr. respectively. The ratios of intensities B/S, Be/S and Be/B have been found to be 0·09±0·02, 0·022±0·008 and 0·25±0·11 respectively. These ratios of intensities have been used (a) to compute the amount of matter traversed by the radiation before reaching the vicinity of the earth as 2·6±0·6 g./cm.², (b) to show that the Fermi mechanism of acceleration of particles is not efficient at these energies (1–10 GeV/n.) in interstellar space and (c) to show that preferential acceleration of H₁-nuclei (Z?20) is not of overwhelming importance. The derived source composition of nuclei of energy ?7·5 GeV/n suggests that N, O, F and H₃-nuclei (Z=10–15) have similar abundances in the universe and in cosmic rays, and that C and H₁-nuclei are overabundant in cosmic rays.     

Spectrophotometric investigation of beryllium-2-hydroxy chalcone complex

2′-Hydroxy chalcone gave an intense orange-yellow color with beryllium in the pH range 5·5–6·2. The limits of identification and dilution were 0·125γ and 1:4 × 10⁵ respectively. A detailed spectro-photometric investigation of the color reaction was carried out. The complex obeyed Beer’s Law in the concentration range of 0·5–6·0p.p.m. at 460 nm. In the complex the ratio of metal to ligand is 1:2. The instability constant of the complex was 2·176 × 10^?6 at 28°. Oxalate, tartrate, citrate and fluoride interfered. The tolerance limits of iron, aluminium, chromium, uranium, thorium and vanadium are reported.     

Equivariant cohomology distinguishes the geometric structures of toric hyperkähler manifolds

Toric hyperkähler manifolds are the hyperkähler analogue of symplectic toric manifolds. The theory of Bielawski and Dancer tells us that, while a symplectic toric manifold is determined by a Delzant polytope, a toric hyperkähler manifold is determined by a smooth hyperplane arrangement. The purpose of this paper is to show that a toric hyperkähler manifold up to weak hyperhamiltonian T -isometry is determined not only by a smooth hyperplane arrangement up to weak linear equivalence but also by its equivariant cohomology H* _T (M; ?) with a point â in H ²(M;?) \ {0} up to weak H*(BT; ?)-algebra isomorphism preserving â.     

An improved method of silicon-32 measurement of groundwaters

A rapid method of separation of³²P from³²Si by hydrofluorisation saves considerable amount of time besides being more efficient in the chemical recovery of phosphorus. Similarly, 4π beta counting of³²P activity allows a more accurate estimation of small amounts of this activity. These improvements make it possible to reliably measure amounts of³²Si as low as 0·1 dpm present in about 10 tons of water.     

Studies in the separation and determination of zirconium using vanillin as an analytical reagent

Vanillin, quantitatively precipitates zirconium between pH 5·0–6·5, as insoluble complex. This complex on ignition gives ZrO₂ which can be weighed. Zirconium can be readily separated and determined in the presence of varying quantities of chromium (III), cobalt (II), copper (II), manganese (II), molybdenum (VI), nickel (II), titanium (IV), tungsten (VI), uranium (VI), vanadium (V), zinc (II) and trivalent rare earths.     

Geochemical studies in the uranium prospect at Umra,Rajasthan

With the objective of investigating the geochemistry of the natural waters of the uranium prospect at Umra, Rajasthan, the concentrations of uranium, nickel, cobalt, copper, vanadium, etc., in the natural waters have been determined and their distribution patterns have been interpreted in the light of the geology of the area, the climatic and hydrological conditions prevalent there and the geochemical behaviour of the elements concerned. It is found that there is a marked contrast in the uranium content of winze and well-waters. The presence of copper in waters despite their high pH is ascribed to the tendency of copper to form colloidal suspension of basic carbonates. The observation, that vanadium is present in the secondary uranium-vanadium minerals but is absent in the waters, could be explained in the light of the geochemical behaviour of the element. The concentration of cobalt in most of the water samples and its absence in some is traceable to the controlling effect of pH on the mobility of cobalt. Nickel in waters might have been ‘scavenged’ and absorbed on hydrated iron oxides, which explains the absence of nickel in waters. Mention is made of the health hazard involved in drinking water from one of the wells with high content of uranium.     

Spectrophotometric studies of uranium (VI)-pongamol complex

The spectrophotometric studies of uranium (VI)-pongamol complex have been carried out in 50% aqueous ethanolic solutions. Pongamol produces a yellow complex with an aqueous uranyl salt solution, the complex is soluble in 50% aqueous ethanol. The complex is quite stable for 24 hours, the optical density remaining constant at pH 5·6–7·1. The complex obeys Beer-Lambert’s law at 390 mµ in the concentration range of 1 to 5 p.p.m. of uranium in solution. The molar composition of the pongamol uranium (VI) complex has been found to be 2:1, and its tentative structure has been suggested. The cations and anions which interfere in the estimation of uranium using pongamol have been indicated.     

Affine Kähler hypersurfaces satisfying certain conditions on the curvature tensor

The notion of affine Kähler immersions has been recently introduced by Nomizu-Pinkall-Podestà ([N-Pi-Po]). This work is aimed at giving some results towards the classification of non degenerate affine Kähler hypersurfaces with symmetric and parallel Ricci tensor; this problem generalizes the classical results due to Nomizu-Smyth ([N-S]) in the theory of Kählerian hypersurfaces. In a second section we deal with the case of “semisymmetric” affine Kähler immersions, when the curvature tensor R satisfies R · R = 0 and the Ricci tensor is symmetric, providing a complete classification; for affine Kähler curves we prove that the conditions above are actually equivalent to saying that the immersion is isometric for a suitable Kähler metric in C².     

Polarographic study of the acid hydrolysis of ketoximes

Kinetics of the acid hydrolysis of acetophenone exime and its substituted compounds have been investigated polarographically. A detailed study of the hydrolysis of acetophenone oxime in 0·05–1·0 M HCl indicated that the rate determining step varied with acid concentration. The reaction in acid concentrations below 0·3M is catalysed by hydrogen ions while general base catalysis by water is predominant in high acid concentrations. Addition of methanol is found to decrease the rate of hydrolysis predominantly.     

On a generalization of Rubin's theorem

The work is devoted to the calculation of asymptotic value of the choice number of the complete r‐partite graph K_{m* r} = K_{m, …, m} with equal part size m. We obtained the asymptotics in the case lnr = o(lnm). The proof generalizes the classical result of A.L. Rubin for the case r = 2. © 2010 Wiley Periodicals, Inc. J Graph Theory 67: 226–234, 2011 67: 226‐234, 2011     

He3 nuclei in the low energy primary cosmic radiation

The flux of He³ nuclei and the ratio He³/(He³+He⁴) in the low energy primary cosmic radiation have been determined using a stack of nuclear emulsions exposed at 3·1 g. cm.^?2 of atmospheric depth from Fort Churchill, Canada, in June 1963. The grain-densityversus residual range method was used to determine the masses of the helium nuclei. Using a sample of 146 helium nuclei whose masses could be identified, the ratio He³/(He³+He⁴) is obtained as 0·14±0·04 for the kinetic energy interval 115–210 MeV per nucleon and 0·43±0·11 for the rigidity interval 0·85–1·05 BV. The differential fluxes of He³ nuclei are determined as 0·017±0·006, 0·045±0·015, and 0·054±0·017 particles/M². Sr. Sec. MeV/nucleon, in the kinetic energy intervals of 117–183, 183–217, and 217–250 MeV/nucleon respectively. These results are compared with those of other investigators. From the results of the present work the amount of matter traversed in space by the primary cosmic ray helium nuclei of energy 115–210 MeV/nucleon is obtained as 4·7±1·8 gm. cm.^?2 of hydrogen.     

Colorimetric estimation of rapox by ferric chloride solution

A method has been developed for estimating even one part per million RAPOX in aqueous medium using Lumetron photoelectric colorimeter 402-E and 620-M filter. The colour of RAPOX ferric complex has been found to obey Beer’s law in the range 10^?5?2·2×10^?4 mole per litre of the aqueous solution. The method depends on the development of colour on mixing aqueous RAPOX with ferric chloride solution in water.     

Cosmic ray nuclei of chargeZ⩾3 during the period of low solar activity

A detailed study of the composition and energy spectra of heavy nuclei of charge Z?3 in the primary cosmic rays has been made during the period of low solar activity, using two stacks of nuclear emulsions exposed in balloon flights from Fort Churchill, Canada, in June 1963. Each of the stacks was composed of 120 nuclear emulsions of three different sensitivities and was exposed at about 3·5 g. cm.^?2 of residual air for about 11.1 hr. Reliable resolution of charges of nuclei from lithium to oxygen was obtained; for heavier nuclei, charge groups were determined. From the analysis of 793 tracks of nuclei with Z?3, results on the following aspects were obtained:

1. The differential energy spectra of L (Z=3–5), M (Z=6–9) and H (Z=10–28) nuclei were measured in the energy intervel 150–600 MeV/nucleon; integral fluxes were obtained for energy >600 MeV/nucleon;
2. The energy dependence of the L/M ratio at the top of the atmosphere was determined; the ratios were obtained as 0·45 ± 0·06 and 0·29 ± 0·03 in the energy intervals of 200–575, and >575 MeV/nucleon respectively;
3. Relative abundances of individual nuclei of Li, Be, B, C, N and O at the top of the atmosphere were determined as 36, 29, 55, 100, 60 and 106 respectively in the energy interval 150–600 MeV/nucleon; corresponding values were also obtained for energy >600 MeV/nucleon.
4. The differential fluxes of multiply charged nuclei measured by us and by other investigators were used to determine the solar modulation between solar maximum to solar minimum. It was found that solar modulation of the fluxes of M and He nuclei were consistent with Rβ dependence and that the modulation parameter Δη between 1965 and 1957 was about 1·1.

The implications of these results are discussed.     

Ratio of pions to protons and ratio of neutral to charged interacting particles at mountain altitude of 800 gm/cm2

Using a combined set-up of a multiplate cloud chamber, an air Cerenkov counter and a total absorption spectrometer, the ratio of pions to protons not associated with large air showers has been determined to be 0·50 ± ·07 in the energy region 20–40 GeV at an altitude of 800 gm/cm². In the same energy region the ratio of neutral to charged particles is found to be 0·66 ± ·07. From the ratio of neutrons to protons deduced from these measurements (i.e., 0·99 ± ·11), it is concluded that most of the charge excess of nuclear active particles of energies > 20 GeV at mountain altitudes and sea-level is due to pions.     

Investigations on multiply charged nuclei of the primary cosmic radiation near the geomagnetic equator using nuclear emulsions

The charge spectrum obtained from measurements made on tracks of 1329 nuclei of the cosmic radiation of Z?6 and E?7·5 GeV/n has been studied in detail using emulsion stacks exposed over Hyderabad, India (cut off rigidity=16·8 GV) at a depth of 6·8 g/cm² of air for 7¼ hrs. This spectrum has been compared with that available for nuclei of E≥1·5 GeV/n. Within the limits of experimental errors, no dependence of the flux values or ratios of intensities with energy are noticed. This result has important implications on the origin and history of the cosmic radiation. Integral energy spectra of M and H-nuclei have been derived making use of the flux values at the two locations; the spectra thus derived have the least errors associated with these.