Soil pipe contribution to steady subsurface stormflow

Flow through a saturated idealized hillslope with a single soil pipe was simulated using a finite difference solution to the equation for three-dimensional Darcian flow in saturated heterogeneous media. The proportions of hillslope discharge originating from flow through the soil matrix and from flow through a soil pipe were determined, considering such factors as the radius, depth and length of the pipe, pipe spacing, and the length and slope of the hillslope. Results demonstrate that soil pipes can contribute a significant amount, and in many instances, the majority of total subsurface stormflow.     

Further observations of 8-μm polar brightenings of Jupiter

North to south scans of Jupiter at 7.8-μm wavelength in early 1981 confirm polar brightening events that correlate with LCM_III, such that a polar limb is bright when the corresponding magnetic pole is tilted eartward. The correlation with magnetic features of the planet suggests that the energy source for the brightenings is magnetospheric particles incident upon the polar regions of the atmosphere. The northern polar events are more prominent and more regular than the southern ones. The polar emission may be indirectly related to the ultraviolet absorber observed near the poles by Voyager 2.     

Fine‐grained,spinel‐rich inclusions from the reduced CV chondrites Efremovka and Leoville: I. Mineralogy,petrology, and bulk chemistry

Abstract— Fine‐grained, spinel‐rich inclusions in the reduced CV chondrites Efremovka and Leoville consist of spinel, melilite, anorthite, Al‐diopside, and minor hibonite and perovskite; forsterite is very rare. Several CAIs are surrounded by forsterite‐rich accretionary rims. In contrast to heavily altered fine‐grained CAIs in the oxidized CV chondrite Allende, those in the reduced CVs experienced very little alteration (secondary nepheline and sodalite are rare). The Efremovka and Leoville fine‐grained CAIs are ¹⁶O‐enriched and, like their Allende counterparts, generally have volatility fractionated group II rare earth element patterns. Three out of 13 fine‐grained CAIs we studied are structurally uniform and consist of small concentrically zoned nodules having spinel ± hibonite ± perovskite cores surrounded by layers of melilite and Al‐diopside. Other fine‐grained CAIs show an overall structural zonation defined by modal mineralogy differences between the inclusion cores and mantles. The cores are melilite‐free and consist of tiny spinel ± hibonite ± perovskite grains surrounded by layers of anorthite and Al‐diopside. The mantles are calcium‐enriched, magnesium‐depleted and coarsergrained relative to the cores; they generally contain abundant melilite but have less spinel and anorthite than the cores. The bulk compositions of fine‐grained CAIs generally show significant fractionation of Al from Ca and Ti, with Ca and Ti being depleted relative to Al; they are similar to those of coarsegrained, type C igneous CAIs, and thus are reasonable candidate precursors for the latter. The finegrained CAIs originally formed as aggregates of spinel‐perovskite‐melilite ± hibonite gas‐solid condensates from a reservoir that was ¹⁶O‐enriched but depleted in the most refractory REEs. These aggregates later experienced low‐temperature gas‐solid nebular reactions with gaseous SiO and Mg to form Al‐diopside and ±anorthite. The zoned structures of many of the fine‐grained inclusions may be the result of subsequent reheating that resulted in the evaporative loss of SiO and Mg and the formation of melilite. The inferred multi‐stage formation history of fine‐grained inclusions in Efremovka and Leoville is consistent with a complex formation history of coarse‐grained CAIs in CV chondrites.     

THE TOULON METEORITE: A NEW CHONDRITE FROM ILLINOIS

Toulon is an olivine-bronzite chondrite found near Toulon, Illinois in 1962. It contains abundant, well preserved chondrules, as well as glasses that are not well devitrified. Most of the metal has been weathered out. Olivine and pyroxene are well equilibrated. We have classified it as an H5 chondrite.     

An XMM–Newton observation of Abell 2597

We report on a 120-ks XMM–Newton observation of the galaxy cluster Abell 2597 (A2597). Results from both the European Photon Imaging Camera (EPIC) and the Reflection Grating Spectrometer (RGS) are presented. From EPIC we obtain radial profiles of temperature, density and abundance, and use these to derive cooling time and entropy. We illustrate corrections to these profiles for projection and point spread function (PSF) effects. At the spatial resolution available to XMM–Newton , the temperature declines by around a factor of 2 in the central 150 kpc or so in radius, and the abundance increases from about one-fifth to over one-half solar. The cooling time is less than 10 Gyr inside a radius of 130 kpc. EPIC fits to the central region are consistent with a cooling flow of around 100 solar masses per year. Broad-band fits to the RGS spectra extracted from the central 2 arcmin are also consistent with a cooling flow of the same magnitude; with a preferred low-temperature cut-off of essentially zero. The data appear to suggest (albeit at low significance levels below formal detection limits) the presence of the important thermometer lines from Fe  xvii at 15–17 Å rest wavelength, characteristic of gas at temperatures ∼0.3 keV. The measured flux in each line is converted to a mass-deposition estimate by comparison with a classical cooling flow model, and once again values at the level of 100 solar masses per year are obtained. These mass-deposition rates, whilst lower than those of previous generations of X-ray observatories, are consistent with those obtained from ultraviolet data for this object. This raises the possibility of a classical cooling flow, at the level of around 100 solar masses per year, cooling from 4 keV by more than two orders of magnitude in temperature.     

THE NAZARETH(b) METEORITE

The Nazareth(b) meteorite is a medium octahedrite found in 1968 near Nazareth, Texas. It contains 8.75% nickel and large schreibersite inclusions     

The chromospheric magnetograph

By comparison of photoelectric magnetograms with high resolution Hα pictures it is possible to formulate a set of rules by which the magnetic field may be derived directly from the filtergrams. This is possible because of the regularities of magnetic field configurations on the sun and because chromospheric morphology is determined by the magnetic field. Off-band pictures (preferably 0.5 Å red) show a well-defined enhanced chromospheric network, the boundaries of which coincide with the 5 G contour of longitudinal field on the Mt. Wilson magnetograms. The actual fields are presumably more concentrated along the dark structure of the network. Higher fields are marked by filled-in cells. Regions of predominantly transverse fields may be inferred from the absence of normal network structure and the presence of chromospheric fibrils. The quiet chromosphere is recognized by the presence of oscillatory motion and the absence of fibrils or strong network structure. Thus, the chromosphere may be divided into three types of regions: enhanced network, horizontal field, and quiet network. The polarity of the magnetic field may be recognized by plage-antiplage asymmetry; that is, the fact that only following magnetic fields show bright plage in the center of Hα.     

Instability analyses of Merhülietsa slide, Kohima, Nagaland

Part of Merhülietsa colony of Kohima town and the national highway passing through it was devastated by a landslide on May 13, 2007. This unstable zone affected by rotational failure lies in the Disang sediments comprising shale with intercalations between thin-bedded siltstone and fine-grained sandstone. The shales are sheared, crumpled, and weathered to a high degree. This is attributed to a strike-slip fault and two shear fractures. Geotechnical analysis was carried out in the area and a factor of safety of 0.60 obtained for the slide mass. Similar work is extended to the surrounding area which had developed tension fractures. A slip circle drawn from tension cracks helps define future failure planes. A factor of safety of 0.93 is obtained indicating the possibility of progression of the slide zone. Rock mass rating of the shales surrounding the slide zone indicates poor rock condition, pointing to danger of collapse with further progression of the slide zone.