Abundance of sulfur in Eocene coal beds from Bapung, Northeast India

At 625°C the percentage of sulfur in the non-volatile portion of the Bapung coal beds ranges from 1.08 to 3.10 wt.%, with the pyritic sulfur ranging from 0.02 to 0.32 wt.%, the sulfate sulfur ranges from 0.02 to 0.30 wt.%, and the organic sulfur from 0.88 to 2.49 wt.%. The total sulfur in the Bapung coal ranges from 2.50 to 12.44%. Organic sulfur appears to be more abundant among the different sulfur species. However, the pyritic sulfur increases quickly as the total sulfur content increases at 925°C, the percentage of sulfur in non-volatile portion ranges from 1.27 to 2.54 wt.%, with pyritic sulfur ranging from 0.02 to 0.56 wt.%, sulfate sulfur ranges from 0.04 to 0.16 wt.%, and the organic sulfur from 1.15 to 2.03 wt.%.     

Levels of Organochlorine Pesticide Residues in Some Organs of the Ganges Perch, Lates calcarifer, from the Ganges–Brahmaputra–Meghna Estuary, Bangladesh

Levels of organochlorine pesticide residues (p,p′ DDT, DDD, DDE, Aldrin, Dieldrin, Lindane, Heptachlor and BHC) were analysed in the dry and wet seasons in four organs (muscle, liver, gut and egg samples) of Ganges Perch, Lates calcarifer, collected during October–November–December, 1996 and May–June–July, 1997 from the Ganges–Brahmaputtra–Meghna estuary. The residues were analysed by using gas-chromatography (GC) in electron capture detector (ECD) mode and were verified by thin layer chromatography (TLC). Among the four organs analysed, the residues were found in the order egg > gut > muscle > liver. The pesticide residues were found in the order ∑DDT > Heptachlor >Dieldrin > Aldrin. Higher levels of residues were found during the dry season due to high lipid content in fishes. A positive correlation was observed between the pesticide residues (∑DDT and ∑OCs) and lipid contents of fish, and the correlation was found to be linear. The concentrations of pesticide residues in muscle, liver and gut were below the FAO/WHO (1993) recommended permissible limit except in eggs.     

Effect of non-linear soil–structure interaction on seismic response of tall slender structures

Some structures may be very massive and may have to be located on relatively soft soil. In such cases, the soil adjacent to the structure behaves in a non-linear fashion and affects the response of the structure to the dynamic loading. An approximate hybrid approach to analyse soil–structure systems accounting for soil non-linearities has been developed in this paper. The approach combines the consistent infinitesimal finite-element cell method (CIFECM) and the finite-element method (FEM). The CIFECM is employed to model the non-linear (near-field) zone of the soil supporting the structure as a series of bounded media. The material properties of the bounded media are selected so that they are compatible with the average effective strains over the whole bounded medium during the excitation. The linear zone of soil away from the foundation, the far-field, is modelled as an unbounded medium using the CIFECM for unbounded media. The structure itself is represented by the FEM. The proposed method is used to model the dynamic response of a one-mass structure and a TV-tower supported on a homogenous stratum and excited by an earthquake. It was found that the secondary soil non-linearity might increase or decrease the base forces of tall slender structures depending on the type of structure, frequency content of the input motion and the dynamic properties of the near-field soil.     

Estimation of potential evapotranspiration in Al-Hassa oasis,Saudi Arabia

An accurate estimation of the potential evapotranspiration can be achieved ba applying empirical evapotranspiration coefficients which are determined under Al-Hassa prevailing climatic conditions. Correlation coefficient results indicate that most of the climatological variables have a strong relationship with potential evapotranspiration except wind speed and precipition variables which have a weak relationship. Multiple regression results also indicate that there is a significant effect of some of the climatologiecal variables in the potential evatranspiration and there is no significant effect of the others at the significant level of 0.05. The results of the stepwise regression indicate that evaporation class “A” pan, air temperature, sunshine hours, radiation, relative humidity, and wind speed variables have a significant effect at the significant level of 0.05 on the overall mean monthly potential evapotranspiration of the Blaney-Criddle, Pan Evaporation, and Jensen-Haise, therefore, the equation which has developed for estimating potential evapotranspiration in Al-Hassa is based on these six variables (evaporation class “A” pan, air temperature, sunshine hours, radiation, relative humidity, and wind speed).     

Electrochemical studies of sulphides,II. Measurement of the galvanic currents in galena and the general mechanism of oxygen reduction and xanthate adsorption on sulphides in relation to flotation

Galvanic currents were measured by short circuiting two half cells; PbS  N₂ (g)  KNO₃ | KNO₃  O₂ (g) or H₂O₂  PbS, and then after adding xanthate to the l.h.s. cell. Such addition of xanthate resulted in a 10 fold (with O₂ in the r.h.s. cell) and 100 fold (with H₂O₂ in r.h.s. cell) increase in the short circuit and steady state currents and also lead to bubble attachment on galena in the l.h.s. cell, in nitrogen atmosphere. The results indicated a heterogeneous, two site electrochemical mechanism for the reduction of oxygen and oxidative adsorption of xanthate on galena.     

On the occurrence and strati graphic position of Permo-Carboniferous tillites in Saudi-Arabia

Summary While engaged in geological investigations in the Mundafan and Beni Khatma areas (Saudi Arabia), large igneous and metamorphic erratics of more than 2 m diameter were noticed widely scattered over a length of more than 100 km. Two well defined horizons containing these boulders were noticed in different sections in the Beni Khatma area within the Wajid Sandstone which is of Permian or older age.These boulders, which are both acid to basic igneous and metamorphic rocks, are encountered in nonmarine sequences. The boulders must have been transported from the Arabian Shield lying more than 100 km to the west of the erratics.The very abundant and wide spread nature of the isolated pebbles, cobbles, and boulders and their embedding in a sandy, clayey and silty matrix may constitute strong evidence of ice rifting and frigid climate. Adding to that, that the Mundafan and Beni Khatma areas lie in a region of stable, nonorogenic, cratonic character which never suffered from volcanism or orogeny, present glaciation as the plausible mechanism of transportation of the erratics.These Permo-Carboniferous Arabian tillites are very important as a temporal equivalent to southern hemisphere Permo-Carboniferous glaciations, i. e. South Africa, India and Australia which show substantial field evidence of the late Paleozoic glaciation.

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Zusammenfassung Während geologischer Untersuchungen im Gebiet von Mundafan und Beni Khatma (Saudi-Arabien) wurden erratische Blöcke von mehr als 2 m Durchmesser in weiter Verbreitung nachgewiesen. Sie erscheinen im Anstehenden in 2 abgrenzbaren Horizonten in verschiedenen Profilen im Raum von Beni Khatma. Diese Horizonte sind dem Wajid-Sandstein eingeschaltet, der nach altersmä\ig eindeutigen Hangendschichten noch permisches oder vorpermisches Alter hat und dem Kristallin des Arabischen Schildes aufliegt.Die Erratica (Granite, Basite) sind auf ein 100 km westlich liegendes Muttergestein — Komplex des Arabischen Schildes — zurückzuführen. Sortierung im Profile, Rundungsgrad und Schrammungen deuten auf Tillite. Die unterschiedlichen Geschiebetypen in den beiden auskartierten Niveaus weisen auf etwas verschiedene Liefergebiete im Westen. Die Blöcke sind danach nicht vom autochthonen Kristallin des unmittelbaren Untergrunds — etwa als ehemalige Hangschuttbildung — herzuleiten und zudem vom Präkambrium durch Gestein in der Nubischen Sandsteinfazies getrennt.Die Erratica werden mit einer permo-karbonischen Eisdrift in Beziehung gebracht (vielleicht sind sie auch z. T. fluvio-glazial) und bieten damit einen weitern Anhaltspunkt für paläogeographische und paläoklimatische Diskussionen im Zusammenhang mit der permo-karbonischen Vereisung Gondwanalands.

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Short notice has been published already in Eiszeit u. Gegenwart,14, 121–123, 1963.     

The relation between Rb,Ba and Sr in granitic rocks

The ternary relation between the elements Rb, Ba and Sr in granitoid rocks is discussed. This relation proved to be useful in tracing differentiation trends in acidic suites. Moreover, it has a potentiality for being used as a criterion in genetic problems of granites, i.e. in distinguishing magmatic from metasomatic or granitized granites. The averages of these three elements in the various types of granites are calculated. The Turekian and Wedepohl (1961) two-fold subdivision of granites into high- and low-Ca rocks is elaborated so as to comprise four distinctive types: quartz diorites and granodiorites, normal granites, strongly differentiated granites beside the group of anomalous granites.     

Isotopic composition of some egyptian galena by thermal emission mass spectrometry

Summary The present paper contains some lead isotope analyses on galena specimens occuring in the central part of the Eastern Desert of Egypt. Thermal emission mass spectrometric technique is applied to these analyses. Recent methods of calculations for galena dating are used in determining the geochronological significance of the data. The lead isotopic composition of the samples has revealed the possible existence of two orogenic events accompanied with metallization that took place about 1000 m.y. and 600 m.y. ago.     

An excursion to the Bayuda volcanic field of Northern Sudan

A cluster of well-preserved recent volcanoes in the northern Bayuda Desert make up a more or less continuous field some 520 km² in area surrounded by a number of isolated centres of eruption. The volcanoes are numerous but small; up to 400 m in height and 0.35 km² in volume. Most of them are simple composite volcanoes with a pyroclastic cone skirted by a small lava field erupted from the same vent after explosive eruptions had ceased. In a few instances, however, the cone was eviscerated by more violent eruptions, leaving a deep explosion crater. The lavas are all nepheline-normative alkali basalts and contain a variety of xenocrysts and xenoliths from at least three different sources. The distribution of the recent volcanoes was partly controlled by large granitic ring-intrusions of the Basement Complex country rocks. These intrusions belong to the Younger Granite association of late Precambrian or Lower Palaeozoic age and represent a volcanic-intrusive episode widespread in northern Africa. The complexes are composed of cale-alkaline and peralkaline granites and syenites and a related plexus of dyke swarms.     

Anisotropic radiation transfer in a sphere with internal source

In this work we connect the problem of anisotropic radiation transfer in a sphere with diffuse reflectivity and containing an energy source with the problem of source free amisotropic radiation transfer with isotropic boundary condition. Exact equation for radiation heat flux for the first problem is obtained in terms of the source, the flux and the albedo of the second problem. Modeled kernel is used to represent the anisotropy of the phase function. Numerical results are given.