Uranium (U) concentration and its genetic significance in the phosphorites of the Paleoproterozoic Bijawar Group of the Lalitpur district,Uttar Pradesh,India

The paper presents the uranium (U) concentration and distribution pattern in the Paleoproterozoic phosphorites of Lalitpur district of Uttar Pradesh. The study of thin sections, SEM and XRD reveal that apatite is the essential phosphate mineral while quartz and feldspars are the dominant gangue in the phosphorites of the investigated area. The collophane is observed to be mostly oolitic in form and microspherulitic in texture. The major element geochemistry indicated that the phosphorite samples are rich in P₂O₅, CaO, SiO₂ and Fe₂O₃ whereas depletion of MgO, MnO, K₂O and Al₂O₃ was observed. The CaO/P₂O₅ ratio ranges from 1.13 to 1.46 which is slightly lower than that of cations and anions substituted francolite (1.621) and close to that of carbonate-fluorapatite (1.318). The trace element geochemistry indicates that the phosphorites of Lalitpur have the significant range of U concentration (1.67 to 129.67 μg/g) which is more than that of Th (0.69 to 0.09 μg/g) among the analysed trace elements in the phosphorite samples of the area. The positive correlation of U with P₂O₅, CaO and U/P₂O₅ indicates a close association of U with phosphate minerals like collophane (apatite), whereas negative correlation of U with SiO₂ and Fe₂O₃ may be due to mutual replacement. The antipathetic relationship of U with Ni may be an indication of high oxidizing conditions, whereas sympathetic relationship of U with K₂O points towards higher alkaline conditions of the basin of deposition during phosphatization. The variable concentration of U and its relationship with significant major and trace elements in most of the phosphorite samples lead one to believe that the deposition of these phosphorites might have taken place in highly alkaline medium during fairly oxidizing to weakly reducing environmental conditions of geosynclinal basin.     

Astronomical research activities with the 74 inch telescope at Kottamia observatory

Two topics of research, namely extragalactic and variable star studies represent the main attitudes of astronomical work at the Helwan Observatory.The 74 inch telescope at Kottamia (476 m, 2^h.12, 29^°.93 N) some 60 km to the east of Cairo is the main instrument. Some other auxiliary equipment (Cassegrain and echelle spectrographs, Westinghouse and Japanese cameras and photoelectric photometer) can be attached at both Cassegrain and Newtonian foci.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Detailed isophotometry of some galaxies,I

Results from a detailed isophotometric survey of NGC 5595, NGC 5597, NGC 5605, and NGC 7769 are given. It includes isophotic maps, luminosity profiles and ellipticity curves as well. Scanning of these galaxies was done in theB andV colours.     

Evaluation of the physico-mechanical parameters affecting the deterioration rate of Ahlat ignimbrites (Bitlis,Turkey)

The paper principally focuses on the durability assessment of various stratigraphic levels of Ahlat ignimbrites collected from the eastern region of Turkey. A total of four different ignimbrite types with dissimilar color, texture and particularly welding degree were tested in laboratory. The laboratory tests performed on the ignimbrite specimens indicate that the welding degree as well as the lithic material content mainly controls the strength and capillarity properties of the ignimbrites. In addition, the durability of highly porous ignimbrites strongly depends upon the degree of welding. The effect of several weathering agents on the ignimbrites was evaluated on the basis of decay constant parameter. Accordingly, salt and ice crystallization pressures are a couple of major destructive agents acting within the micropores of the ignimbrites. Conversely, the investigated specimens are relatively durable against cyclic wetting–drying. Statistical evaluations reveal that the pore diameter is the major controlling factor on the deterioration rate of the ignimbrites after specifically recurrent freeze–thaw cycles. Moreover, the dry unit weight of the ignimbrites is more significant than the uniaxial compressive strength considering the deterioration rates during wetting–drying and salt crystallization. A less significant relationship was obtained between pore diameter and salt crystallization decay constant.     

Large Earthquakes at the Ibero-Maghrebian Region: Basis for an EEWS

Large earthquakes (M_w > 6, I_max > VIII) occur at the Ibero-Maghrebian region, extending from a point (12ºW) southwest of Cape St. Vincent to Tunisia, with different characteristics depending on their location, which cause considerable damage and casualties. Seismic activity at this region is associated with the boundary between the lithospheric plates of Eurasia and Africa, which extends from the Azores Islands to Tunisia. The boundary at Cape St. Vincent, which has a clear oceanic nature in the westernmost part, experiences a transition from an oceanic to a continental boundary, with the interaction of the southern border of the Iberian Peninsula, the northern border of Africa, and the Alboran basin between them, corresponding to a wide area of deformation. Further to the east, the plate boundary recovers its oceanic nature following the northern coast of Algeria and Tunisia. The region has been divided into four zones with different seismic characteristics. From west to east, large earthquake occurrence, focal depth, total seismic moment tensor, and average seismic slip velocities for each zone along the region show the differences in seismic release of deformation. This must be taken into account in developing an EEWS for the region.     

Concentration of selected radionuclides in seawater from Kuwait

No baseline existed for the radionuclides in Kuwait territorial water. With changing trend in the region to embrace nuclear energy, the baseline study is imperative to create a reference and to record the influence-functioning of upcoming power plants. The first one in Bushehr, Iran is ready to start and several more are likely to come-up in UAE, Saudi Arabia and Kuwait. The present baseline concentration of the four considered radionuclide's show low concentration of tritium, polonium, strontium and cesium; their concentration is comparable to most oceanic waters.     

Biosorption of methylene blue from aqueous solutions by Typha angustata phytomass

The objective of this study was to investigate the biosorption of an azo dye (Methylene blue) by a wetland phytomass (Typha angustata) under post-phytoremediation scenario. Thus, the phytomass was used without any chemical modification. The batch adsorption experiments were conducted to evaluate the effects of contact time and temperatures (25–45 °C) on the adsorption of methylene blue (MB) from aqueous solution by cattail phytomass (CP). More than 80 % of MB dye was removed from the aqueous solution within first 10 min of the experiment. Langmuir isotherm was modeled to describe the monolayer adsorption of MB dye (R ² = 0.995) with the maximum adsorption capacity of 8.1 mg/g at 25 °C. Pseudo-second-order kinetic model adequately described the kinetics of absorption process (R ² = 0.999). The adsorption of MB on the cattail phytomass was a spontaneous and endothermic process that was governed by chemisorption. Hence, CP could be applied as a potential low cost biosorbent to treat dyeing wastewater.     

On possible influence of space weather on agricultural markets: Necessary conditions and probable scenarios

We present the results of study of a possible relationship between the space weather and terrestrial markets of agricultural products. It is shown that to implement the possible effect of space weather on the terrestrial harvests and prices, a simultaneous fulfillment of three conditions is required: 1) sensitivity of local weather (cloud cover, atmospheric circulation) to the state of space weather; 2) sensitivity of the area-specific agricultural crops to the weather anomalies (belonging to the area of risk farming); 3) relative isolation of the market, making it difficult to damp the price hikes by the external food supplies. Four possible scenarios of the market response to the modulations of local terrestrial weather via the solar activity are described. The data sources and analysismethods applied to detect this relationship are characterized. We describe the behavior of 22 European markets during the medieval period, in particular, during the Maunder minimum (1650–1715). We demonstrate a reliable manifestation of the influence of space weather on prices, discovered in the statistics of intervals between the price hikes and phase price asymmetry. We show that the effects of phase price asymmetry persist even during the early modern period in the U.S. in the production of the durum wheat. Within the proposed approach, we analyze the statistics of depopulation in the eighteenth and nineteenth century Iceland, induced by the famine due to a sharp livestock reduction owing to, in its turn, the lack of foodstuff due to the local weather anomalies. A high statistical significance of temporal matching of these events with the periods of extreme solar activity is demonstrated. We discuss the possible consequences of the observed global climate change in the formation of new areas of risk farming, sensitive to space weather.     

Thrust controlled lineaments of the Aravalli-Delhi fold Belt, Rajasthan, India mapped from landsat TM image

The litho-units of the area between Chawand to Kotra across the Aravalli-Delhi Fold Belt are referable to Bhilwara, Aravalli and and Delhi Supergroups. Earlier workers considered the sequence as progressively younger toward west across the Avavalli Orographic axis. Two-dimensional trend mapping of the planar tectonic anisotropy was carried out to map lineaments from landsat TM Image. Ground checks of the lineament along Chawand-Kotra section suggest that lineaments are tectonic dislocations, morphotectonically controlled by thrusts and ductile shears within the Aravalli-Delhi Fold Belt. The recognition of thrust bounded litho-tectonic units from interpretation of satellite remotely sensed data may necessitate reassessment of the Precambrian lithostraligraphy of the Aravalli and Delhi supergroups in the study area. The paper reports thrust tectonics from Aravalli-Delhi Fold Bell. The Antalia Schuppean Belt is possible duplex; imbricate thrusts are connected with base thrust and continuity with roof thrust has been punctuated by transverse faulting and erosion.