Estimation of the dissociation energy of CO+ from spectroscopic data

The potential energy curves for theX ² Σ⁺ andB ² Σ⁺ states of CO⁺ have been constructed by the Rydberg-Klein-Rees (RKR) method as modified by van der Sliceet al. The dissociation energy is estimated to be 7.70±0.19 eV by the method of curve fitting using the five parameter Hulburt-Hirschfelder’s function. The estimated value is in good agreement with the value (7.839 eV) given by Misraet al. Carefull observation of the results reveals that accurateD ₀ value for CO⁺ is 8.33 eV     

Variation of lunar and solar geomagnetic tides with sunspot and geomagnetic activity

Summary Solar and lunar geomagnetic tides inH at Alibag have been determined by spectral analysis of discrete Fourier transforms following the method of Black and the well-known Chapman-Miller method. The seasonal variation inL ₂(H) is opposite to that inL ₂(D) with maximum in thed season and minimum in thej season. In bothH andD the enhancement due to sunspot activity is larger in lunar tide than in solar tide. Surprisingly, the enhancement due to magnetic activity is greater inL ₂(H) than inS ₁(H), while the contrary is true for declination. It is inferred that there is a local time component of the storm time variation contrary to the view expressed by Green and Malin. The enhancements in amplitudesL ₂ andS ₁ inH andD, due to sunspot activity and due to magnetic activity, have been separated. The results show that the amplitude at zero sunspot number increases with magnetic activity in all the four parameters, while the enhancement due to sunspot activity at different levels of magnetic activity decreases with increase ofK _p. But if bothK _p andR are increasing, whenK _p increases enhancement due toR decreases and whenR increases enhancement due toK _p decreases.     

The influence of barrier beach on sediment transportation in the Kakinada Bay

Summary Studies upon the changes of bottom topography in the vicinity of Godavari point and Kakinada Bay indicates recession of contours towards the shore as a result of net loss of sediment since the formation of Kakinada Bay. The sand spit has been growing in the north-westerly direction reducing the width of the opening between the Kakinada Bay and the open Ocean. The currents across the opening strengthen resulting rapid erosion of the bottom of the Bay. The beach to the north of the Kakinada Bay entrance channel is building up. In the present investigation, the authors made an attempt to explain the shore line changes and changes in bottom topography in the Kakinada Bay from the currents measured under different tidal conditions around the sand spit (Godavari Point.)     

Mineralogy and chemistry of the iron ores of Nainarmalai,Tamilnadu

The magnetite-quartzites of Nainarmalai forms part of a large iron ore belt of Tamilnadu which occurs in a high grade granulite terrain. They are associated with basic granulites and gneisses. Mineralogical and chemical studies indicate their similarities with other metasedimentary iron ores.     

Analysis and planning of Saharanpur region for development and growth using remote sensig techniques

In this study the analysis of Saharanpur region has been done at Roorkee University for the development and growth of the region, using Landsat Imagery of November, 1972 (Bands 5 and 7) after enlarging it to a Scale of 1:250,000. Land utilization map (by visual interpretaion) was prepared, on the base map obtained from 250,000 toposheet, interpreting three main element of the image i.e. tone, texture and pattern-Sample verification of the landuses obtained was done by the interpretation of 1:10,000 scale photos for plains and 1:60,000 scale photographs for hilly area and found quite reasonable. Some of the information about population and the distribution of population according to the sizes of the settlements are found by the census report. The road work information is obtained from the toposheet and aerial photographs. After getting this information, hierarchy of settlements, land utilizaton onward settlement, population of the settlements, road conncetions between settlements and the size of the settlements are determined. The strategy for development of Growth centres is thought out and the facilities of these Growth centres are proposed. It has been found that the remote sensing technique gives a hierarchy by which optimum location of growth centres in the region is comparatively very easy, time saving and economical.     

Groundwater quality in the Niva River basin, Chittoor district, Andhra Pradesh, India

 This study was made to assess the groundwater quality in relation to agricultural and domestic uses in a part of the Peninsular Archean granite and gneissic complex of India. Water samples were collected from the existing wells in the Niva River basin, Chittoor district, Andhra Pradesh, India and analysed for major ions. The analytical data, processed and interpreted acoording to the WHO standards, reveal that, in general, the groundwater is suitable for both agricultural and domestic uses, exept in a few locations. High concentration of nitrates were observed in some of the wells (both agricultural and domestic) that are affected by the impact of industrial effluents. Multiple regression analysis was performed and used as a positive predictive tool in understanding the chemistry of the groundwater. Received: 2 May 1996 / Accepted: 14 October 1996     

A microstructural and argon laserprobe study of shear zone development at the western margin of the Nanga Parbat–Haramosh Massif,western Himalaya

A sample of banded amphibolite from the western margin of the Nanga Parbat–Haramosh Massif as Sassi has been studied using microstructural and ⁴⁰Ar/³⁹Ar laserprobe techniques to investigate the relationship between deformation and argon isotope variations in a natural system. Amphibolite-grade deformation occurred during south-directed overthrusting of the Kohistan arc over India along the Main Mantle Thrust and was overprinted by extensional reactivation of the earlier fabric and the formation of biotite-rich shear zones. Subsequent deformation along discrete fine-grained fault zones was characterised by the formation of scapolite, chlorite and K-feldspar, early plastic deformation and later cataclasis. Different minerals developed during this history show a wide range in apparent ⁴⁰Ar/³⁹Ar ages. Biotite, chlorite and scapolite exhibit much lower concentrations of excess argon, indicating their equilibration in a fluid relatively poor in excess argon. A `true' age of ca. 8 Ma from biotite represents a minimum age for deformation associated with formation of the Nanga Parbat Syntaxis and also precludes Pliocene metamorphism in this area of the syntaxis. Both high- and low-closure temperature minerals (amphiboles and feldspars) record apparent ages which are associated with the incorporation of excess argon within the mineral lattice. Although differential thermal resetting of minerals at different closure temperatures is important, variations in the inherited ⁴⁰Ar/³⁶Ar ratio throughout the sample is dominated by deformation and fluid infiltration. Consequently it appears that within deforming metamorphic rocks, areas with significantly different argon isotope compositions may be present and need not be homogenised by diffusion. Received: 6 July 1994 / Accepted: 24 December 1996     

40Ar/39Ar ages in deformed potassium feldspar: evidence of microstructural control on Ar isotope systematics

Detailed field and microstructural studies have been combined with high spatial resolution ultraviolet laser ⁴⁰Ar/³⁹Ar dating of naturally deformed K-feldspar to investigate the direct relationship between deformation-related microstructure and Ar isotope systematics. The sample studied is a ~1,000 Ma Torridonian arkose from Skye, Scotland, that contains detrital feldspars previously metamorphosed at amphibolite-facies conditions ~1,700 Ma. The sample was subsequently deformed ~430 Ma ago during Caledonian orogenesis. The form and distribution of deformation-induced microstructures within three different feldspar clasts has been mapped using atomic number contrast and orientation contrast imaging, at a range of scales, to identify intragrain variations in composition and lattice orientation. These variations have been related to thin section and regional structural data to provide a well-constrained deformation history for the feldspar clasts. One hundred and forty-three in-situ ⁴⁰Ar/³⁹Ar analyses measured using ultraviolet laser ablation record a range of apparent ages (317-1030 Ma). The K-feldspar showing the least strain records the greatest range of apparent ages from 420-1,030 Ma, with the oldest apparent ages being found close to the centre of the feldspar away from fractures and the detrital grain boundary. The most deformed K-feldspar yields the youngest apparent ages (317-453 Ma) but there is no spatial relationship between apparent age and the detrital grain boundary. Within this feldspar, the oldest apparent ages are recorded from orientation domain boundaries and fracture surfaces where an excess or trapped ⁴⁰Ar component resides. Orientation contrast images at a similar scale to the Ar analyses illustrate a significant deformation-related microstructural difference between the feldspars and we conclude that deformation plays a significant role in controlling Ar systematics of feldspars at both the inter- and intragrain scales even at relatively low 'bulk' strains. The data show that Ar loss and trapping within the deformed K-feldspars reflects the presence of a deformation-induced population of small diffusion domains in combination with 'short-circuit' diffusion along deformation-induced defects. The complex history of microstructures induced in the K-feldspars during their cooling, alteration, erosion and sedimentation do not appear to be as significant as deformation-induced microstructures in controlling the distribution of apparent ages at the grain scale.