Cylindrically symmetric inhomogeneous universe with electromagnetic field in string cosmology

Cylindrically symmetric inhomogeneous string cosmological model in presence of electromagnetic field is investigated. We have assumed that F ₂₃ is the only non-vanishing component of F _ij . To get the deterministic solution, it has been assumed that the expansion (θ) in the model is proportional to the eigen value σ ¹ ₁ of the shear tensor σ ⁱ _j . The physical and geometric aspects of the model are also discussed.      

Absolute sea level determination for the subtropical Atlantic Climate Study

The Subtropical Atlantic Climate Study (STACS) is a subprogram in the NOAA climate program designed to access the feasibility of monitoring horizontal fluxes in the Gulf Stream system off Florida. Transport in the Florida Current fluctuates on time scales which are reflected in sea level records monitored at tide gauges. Geodetic leveling, connecting tide gauges along the east coast of the United States, allows intercomparison of sea level records alongstream, but the cross-stream and alongstream records in the Bahamas and Cuba are not connected. In this study, various methods to determine absolute sea level differences across the Straits of Florida between Miami, Florida and Cat Cay, Bahamas, a part of the STACS area, were investigated; the desired accuracy of the sea level difference is ± 1 cm. This study indicates that a combination of dense gravity data with satellite altimeter (TOPEX and GEOSAT) data in the STACS area could provide a ± 1 cm absolute sea level difference accuracy across the Straits of Florida. This paper also provides discussion of other conventional methods.     

Basement tectonics and flexural subsidence along western continental margin of India

The Paleocene-recent post-rift subsidence history recorded in the Mumbai Offshore Basin off western continental margin of India is examined. Results obtained through 2-D flexural backstripping modelling of new seismic data reveal considerable thermo-tectonic subsidence over last ca. 56 Myr. Reverse postrift subsidence modelling with variable β stretching factor predicts residual topography of ca. 2000 m to the west of Shelf Margin Basin and fails to restore late Paleocene horizon and the underlying igneous basement to the sea level. This potentially implies that:(1) either the igneous basement formed during the late Cretaceous was emplaced under open marine environs; or(2) a laterally varying cumulative subsidence occurred within Mumbai Offshore Basin(MOB) during ca. 68 to ca. 56 Ma. Pre-depositional topographic variations at ca. 56 Ma across the basin could be attributed to the extensional processes such as varied lower crustal underplating along Western Continental Margin of India(WCMI). Investigations about basement tectonics after unroofing of sediments since late Paleocene from this region support a transitional and heavily stretched nature of crust with high to very high β factors. Computations of past sediment accumulation rates show that the basin sedimentation peaked during late Miocene concurrently with uplift of Himalayan-Tibetan Plateau and intensification of Indian monsoon system. Results from basin subsidence modelling presented here may have significant implications for further studies attempting to explore tectono-climatic interactions in Asia.     

Physiography of the tons basin,Western Himalaya

Landsat RBV imagery on 1:500,000 was interpreted to prepare small scale physiography map of the part of the Tons basin. Aerial photographs on 1:60,000 to 1:80,000 scale were interpreted to prepare medium scale physiography map of the basin. The basin has been sub-divided into three physiographic regions viz. High to very high mountains constituting of glaciated and temperate high mountains; Low to moderately high mountains and very low maountains. The physiographic regions have been further sub-divided based on landforms, slope and dissection index. The major physiographic units are summits, repose slopes, serrated ridges with horn/arates; mountain and valley glaciers, morains, solufluction terraces, intrenched incised river valleys, engrown valleys, alluvial terraces, rocky slopes/cliffs and debris.     

Study of morphogenetic characteristics of surgad catchments for watershed management

The problem of surveying watersheds for strategic planning in the Himalayan terrain has attracted the attention of the land surveyors recently. A small watershed in Surgad Catchment has been surveyed to select various parameters that determine soil loss, which can be studied using aerial photo-interpretation technique with a view to watershed management. Soil, slope, landuse and micro climatic factors have been used to delineate different morphogenetic categories. The result shows that on steeper slopes, well developed soils are found which indicates a high tolerance limits of these soils. In Himalayan terrain soils and vegetation are therefore, better indices of sediment losses than slopes. Small scale aerial photographs can be successfully used to judge the tolerance limits of soils in Himalayan terrain.     

Evaluation of reservoir temperatures and local utilization of geothermal waters of the Konkan Coast, India

Geochemical studies on fifteen geothermal manifestations (38–70°C) from the Konkan coast geothermal province of India have been used to evaluate the reservoir temperatures. Activity studies of the minerals and the waters present in the reservoirs suggest that the thermal waters are in equilibrium with montmorillonite, kaolinite and quartz at about 100°C. Reservoir temperatures of these geothermal systems as estimated by geochemical thermometers, are 88 to 128°C, and thus too low for economic electricity production.     

Studies on the Effect of DDT on the Regeneration of Cutaneous Wounds in Mystus (mystus) vittatus Bl. (Bagridae)

The effects of DDT on the regeneration of cutaneous wounds has been studied in Mystus (mystus) vittatus. The fishes were locally collected, they were inflicted incised wounds surgically and kept in 0.01 and 0.15 ppm concentrations of DDT. The regenerating skin at different stages of development ranging from 15 min to 25 d after the injury was studied through microtomy sections. The following toxic effects were studied:

• A small amount of DDT accumulated in the subcutis at the 25 days stage,
• the regeneration of wounds under DDT stress has been slower, delayed or irregular,
• the secretion of fibrinous exudate has been copious,
• epithelization and fibroblastic activities have been slower,
• the higher concentration of 0.15 ppm of DDT produced more toxic effects than the lower concentration of 0.01 ppm,
• the earlier stages of wound healing up to 3 d have been more adversely affected than later stages.

     

Problems in Himalayan geology

The Central Crystalline Axis of the Great Himalaya holds clues to the solution of many problems dealing with the crystallines, metamorphics and geological contrasts encountered in the areas to the north and south of the Axis. The problems discussed include criteria for deciphering the stratigraphy in the Himalayan zone to the south of the Crystalline Axis, age of Jutogh and Chail groups, their relationship with each other and with the Crystalline Axis, nature of the Simla Slates, Jaunsar, Blaini, Infra-Krol, and Krol formations, unfossiliferous nature of the Palaeozoic and Mesozoic sediments, relationship between the Lower, Middle and Upper Tertiaries and the age, presence and absence, and also the cause of metamorphism. It has been found that high grade metamorphism is not a Tertiary phenomenon. Very low grade metamorphism in the sedimentaries and the absence of plutonic intrusives from the Palaeozoic, Mesozoic and Tertiary sedimentary rocks indicate that magmatism, regional metamorphism and orogeny are not always mutually associated in space and time. Orogenic and epeirogenic episodes other than Cretaceous-Tertiary hold clues to many problems of Himalayan Geology.

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Zusammenfassung Die zentrale kristalline Achse des Gro\en Himalaya bietet den Schlüssel für die Lösung vieler Probleme für die im Norden und Süden gelegenen Metamorphite und die geologischen GegensÄtze. Neue Daten für die Deutung der Stratigraphie in der Himalaya-Zone südlich der kristallinen Achse, das Alter der Jutogh- und der Chail-Gruppe, ihre Beziehung untereinander und zur kristallinen Achse, die Natur der Simla Slates sowie der Jaunsar-, Blaini-, Infra-Krol- und Krol-Formation, die Fossilleere der palÄozoischen und mesozoischen Sedimente, die Beziehung zwischen unterem, mittlerem und oberem TertiÄr und schlie\lich Alter, Vorkommen und Fehlen sowie die Ursache der Metamorphose werden gegeben. Hochgradige Metamorphose ist nicht an das TertiÄr gebunden. Niedriggradige Metamorphose in den Sedimenten und das Fehlen plutonischer Intrusiva aus palÄozoischen, mesozoischen und tertiÄren Sedimentgesteinen weisen darauf hin, da\ Magmatismus, regionale Metamorphose und Orogenese nicht immer zeitlich und rÄumlich miteinander verknüpft sind. Orogene und epirogene Episoden au\erhalb von Kreide und TertiÄr können wichtig für die Himalaya-Geologie sein.

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Résumé La zone axiale cristalline du Grand Himalaya apporte la clé pour la solution de nombreux problèmes concernant les métamorphites situées au Nord et au Sud, et les contrastes géologiques qu'elles présentent. De nouvelles données sont apportées sur la stratigraphie dans la zone de l'Himalaya au sud de l'axe cristallin, sur l'âge des groupes de Jutogh et de Chail, sur leurs relations mutuelles et avec l'axe cristallin, sur la nature des formations des phyllades de Simla, de Jaunsar, de Blaini, de l'Infrala nature des formations des phyllades de Simla, de Jaunsar, de Blaini, de l'Infra-Krol et de Krol, sur l'absence de fossiles dans les sédiments du PaléozoÏque et du MésozoÏque sur la présence et l'absence du métamorphisme, ainsi que sur sa cause. Le métamorphisme de degré élevé n'est pas lié au Tertiaire. Le métamorphisme de degré faible dans les sédiments et l'absence d'intrusions plutoniques dans les roches sédimentaires paléozoÏques, mésozoÏques et tertiaires montrent que le magmatisme, le métamorphisme régional et l'orogenèse ne sont pas toujours associés dans l'espace et le temps. Les épisodes orogéniques et épeirogéniques survenant en dehors du Crétacique et du Tertiaire peuvent Être importants pour la géologie himalayenne.

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. , , Jutogh Chail, , Simla Jaunsar, Blaini, Infra-Kroll & Kroll, , , , . . , , , . .

     

Thermodynamic properties of andradite and application to skarn with coexisting andradite and hedenbergite

The enthalpy of formation of andradite (Ca₃Fe₂Si₃O₁₂) has been estimated as-5,769.700 (±5) kJ/mol from a consideration of the calorimetric data on entropy (316.4 J/mol K) and of the experimental phaseequilibrium data on the reactions: 1 $$\begin{gathered} 9/2 CaFeSi_2 O_6 + O_2 = 3/2 Ca_3 Fe_2 Si_3 O_{12} + 1/2 Fe_3 O_4 + 9/2 SiO_2 (a) \hfill \\ Hedenbergite andradite magnetite quartz \hfill \\ \end{gathered} $$ 1 $$\begin{gathered} 4 CaFeSi_2 O_6 + 2 CaSiO_3 + O_2 = 2 Ca_3 Fe_2 Si_3 O_{12} + 4 SiO_2 (b) \hfill \\ Hedenbergite wollastonite andradite quartz \hfill \\ \end{gathered} $$ 1 $$\begin{gathered} 18 CaSiO_3 + 4 Fe_3 O_4 + O_2 = 6Ca_3 Fe_2 Si_3 O_{12} (c) \hfill \\ Wollastonite magnetite andradite \hfill \\ \end{gathered} $$ 1 $$\begin{gathered} Ca_3 Fe_2 Si_3 O_{12} = 3 CaSiO_3 + Fe_2 O_3 . (d) \hfill \\ Andradite pseudowollastonite hematite \hfill \\ \end{gathered} $$ and $$log f_{O_2 } = E + A + B/T + D(P - 1)/T + C log f_{O_2 } .$$ Oxygen-barometric scales are presented as follows: $$\begin{gathered} E = 12.51; D = 0.078; \hfill \\ A = 3 log X_{Ad} - 4.5 log X_{Hd} ; C = 0; \hfill \\ B = - 27,576 - 1,007(1 - X_{Ad} )^2 - 1,476(1 - X_{Hd} )^2 . \hfill \\ \end{gathered} $$ For the assemblage andradite (Ad)-hedenbergite (Hd)-magnetite-quartz: $$\begin{gathered} E = 13.98; D = 0.0081; \hfill \\ A = 4 log(X_{Ad} / X_{Hd} ); C = 0; \hfill \\ B = - 29,161 - 1,342.8(1 - X_{Ad} )^2 - 1,312(1 - X_{Hd} )^2 . \hfill \\ \end{gathered} $$ For the assemblage andradite-hedenbergite-wollastonite-quartz: 1 $$\begin{gathered} E = 13.98;{\text{ }}D = 0.0081; \hfill \\ A = 4\log (X_{Ad} /X_{Hd} );{\text{ C = 0;}} \hfill \\ B = - 29,161 - 1,342.8(1 - X_{Ad} )^2 - 1,312(1 - X_{Hd} )^2 . \hfill \\ \end{gathered} $$ For the assemblage andradite-hedenbergite-calcitequartz: 1 $$\begin{gathered} E = - 1.69;{\text{ }}D = - 0.199; \hfill \\ A = 4\log (X_{Ad} /X_{Hd} );{\text{ C = 2;}} \hfill \\ B = - 20,441 - 1,342.8(1 - X_{Ad} )^2 - 1,312(1 - X_{Hd} )^2 . \hfill \\ \end{gathered} $$ For the assemblage andradite-hedenbergite-wollastonite-calcite: 1 $$\begin{gathered} E = - 17.36;{\text{ }}D = - 0.403; \hfill \\ A = 4\log (X_{Ad} /X_{Hd} );{\text{ C = 4;}} \hfill \\ B = - 11,720 - 1,342.8(1 - X_{Ad} )^2 - 1,312(1 - X_{Hd} )^2 \hfill \\ \end{gathered} $$ The oxygen fugacity of formation of those skarns where andradite and hedenbergite assemblage is typical can be calculated by using the above equations. The oxygen fugacity of formation of this kind of skarn ranges between carbon dioxide/graphite and hematite/magnetite buffers. It increases from the inside zones to the outside zones, and appears to decrease with the ore-types in the order Cu, Pb?Zn, Fe, Mo, W(Sn) ore deposits.     

Terrain analysis of Panna District,Bundelkhand, Madhya Pradesh,using LANDSAT imagery

Visual interpretation of LANDSAT imagery in bands 6 and 7 covering Panna district, Bundelkhand, Madhya Pradesh was carried out for terrain analysis and present land use. The physiographic units viz. hills and hill ranges, escarpments, ridges, table-land, pediment, piedmont plain and sub-units of second order were identified and delineated using inter pretation elements. Area of each unit and sub-unit is calculated and presented in the table showing extent, tone, texture, shape and land use. Land use in relation to physiographic units is also described in the paper and shown in the form of small scale map. Visual interpretation technique helps in broad terrain analysis on scale 1:1 million. This information could be used for making a rapid resource inventory.