Search

In an aqueous solution of ferrous chloride, γ - Glycine Crystal (γ-GC), an efficient nonlinear optical (NLO) material, was created. AR grade glycine and ferrous chloride in a molar ratio of 1: 0.5 were employed to grow the title sample. The lattice properties of γ-GC were determined using a single crystal X-ray diffraction method. High transmittance in the visible area and a UV-visible spectrum make γ-GC excellent for optical applications. Using a Nd:YAG laser, the produced crystal's LDT value was ascertained. The crystal's hardness was assessed using the Vickers test, and other mechanical properties were determined. The electrical properties of γ-GC were examined by measuring the dielectric constant and dielectric loss at various frequencies, and temperatures. Using TG/DTA tests to gauge the sample's thermal stability, the functional groups of the γ-GC were identified by FTIR analysis. The material also underwent SHG and LDT testing. [ABSTRACT FROM AUTHOR]

The paper documents occurrence, origin and significance of glauconite-rich intervals at certain specific stratigraphic levels within Early to Middle Eocene Sylhet Formation of Assam and Assam–Arakan Basin. The microfacies with which glauconite is associated are fossiliferous silty shale, glauconitic sandstone, lime mudstone–wackestone and wackestone–packstone. The glauconites occur in three forms, viz., glauconite pellets, infillings within bioclasts and cements (i.e., non-pellet stringers and blebs), representing a complete spectrum of maturity with presence of four types, nascent, slightly evolved, evolved and highly evolved varieties. The elliptical, immatured pellets occur in glauconitic sandstone and exhibit yellowish-green to grass green colour, while relatively matured pellets are dark brownish green to brown, irregular, broken and mostly associated with shale. The Sylhet glauconites indicate deposition in a tide-affected marginal marine to inner-shelf carbonate ramp with low sedimentation rate, and normal marine salinity and represent an overall fining-up 2nd order TST. High-resolution sequence stratigraphic analysis allows to subdivide the 2nd order TST into 3rd order systems tracts: (i) a basal TST, represented by shale/limestone, (ii) an HST incorporating sandstone, limestone and shale, and (iii) a TST at the top. The intervening 3rd order HST is further subdivided into 4th order parasequence sets separated by marine flooding surfaces. Electrolog correlation reveals that the ubiquitous presence of glauconite-rich horizons corresponds to marine flooding events (MFE) of 3rd and 4th order sea-level changes. The glauconites associated with MFE result in a condensed section with minimum sediment supply and provide a key parameter to build the sequence stratigraphic architecture. The occurrences of green clays may possibly owe their origin due to migration of K+/Fe2+ ions from seawater or surrounding sediments to a given reducing microsystem centered on organic debris. The sources of K and Fe are seawater and detrital minerals, respectively, and are achieved by the diffusion-nucleation-crystal growth process. [ABSTRACT FROM AUTHOR]

Mesoproterozoic lamproite dykes occurring in the Banganapalle Lamproite Field of southern India show extensive hydrothermal alteration, but preserve fresh spinel, apatite and rutile in the groundmass. Spinels belong to three genetic populations. Spinels of the first population, which form crystal cores with overgrowth rims of later spinels, are Al-rich chromites derived from disaggregated mantle peridotite. Spinels of the second population include spongy-textured grains and alteration rims of titanian magnesian aluminous chromites that formed by metasomatic interactions between mantle wall-rocks and precursor lamproite melts before their entrainment into the erupting lamproite magma. Spinels that crystallised directly from the lamproite magma constitute the third population and show five distinct compositional subtypes (spinel-IIIa to IIIe), which represent discrete stages of crystal growth. First stage magmatic spinel (spinel-IIIa) includes continuously zoned macrocrysts of magnesian aluminous chromite, which formed together with Al–Cr-rich phlogopite macrocrysts from an earlier pulse of lamproite magma at mantle depth. Crystallisation of spinel during the other four identified stages occurred during magma emplacement at crustal levels. Titanian magnesian chromites (spinel-IIIb) form either discrete crystals or overgrowth rims on spinel-IIIa cores. Further generations of overgrowth rims comprise titanian magnesian aluminous chromite (spinel-IIIc), magnetite with ulvöspinel component (spinel-IIId) and lastly pure magnetite (spinel-IIIe). Abrupt changes of the compositions between successive zones of magmatic spinel indicate either a hiatus in the crystallisation history or co-crystallisation of other groundmass phases, or possibly magma mixing. This study highlights how different textural and compositional populations of spinel provide important insights into the complex evolution of lamproite magmas including clues to elusive precursor metasomatic events that affect cratonic mantle lithosphere. [ABSTRACT FROM AUTHOR]

Background: Macrotyloma uniflorum Linn. (Fabaceae) seeds are widely used for their diuretic and urolithiatic effects in India. The present study investigated the effect of n-butanol fraction of M. uniflorum (nBFMU) on kidney stone using in vitro and in vivo method. Materials and Methods: Nucleation, crystal growth, crystal aggregation and crystal dissolution assays were performed for nBFMU. Two doses of nBFMU (400 and 800 mg/kg) were studied for their diuretic activity and sodium oxalate (NaOx) (70 mg/kg, i.p) induced urolithasis in male Wistar albino rats. Determination of body and kidney weight, measurement of various biochemical parameters in biological samples and examination of histology of kidney at the end of experiment were also done. Results: nBFMU exhibited a concentration dependent inhibitory activity on nucleation and aggregation along with decreased number of crystals of calcium oxalate (CaOX) produced in metastable solutions of CaOX in the in vitro experiments. Co-administration of nBFMU with NaOX has significantly (p<0.001) increased the urine volume and the level of calculus inhibitors like magnesium, citrate and decreased the level of calculus promoters like oxalate, calcium, urea and uric acid. nBFMU supplement also prevented the pathological changes in kidney and increased the glomerulus activity of the kidney. Conclusion: These results indicate that nBFMU showed significant activity in urolithiasis which might be due to its diuretic, CaOX crystal formation inhibitory effects and its ability to increase the levels of inhibitors and decrease the level of promoters of urolithiasis. [ABSTRACT FROM AUTHOR]

Reappraisal of field relationships between the different lithological ensembles supported by available geochronological data, and taking due note of the tectono-metamorphic, magmatic and sedimentation history helped to build up a coherent crustal evolutionary history of the Singhbhum Archaean craton, eastern India. The evolution of the earliest sialic crust, as the isotope ages suggest, was around 3700 Ma or even earlier. Deposition of the oldest, dominantly metasedimentary supracrustals, the Older Metamorphic Group (OMG), was initiated at around 3380 Ma, i.e. after a gap of about 320 million years. The closing of OMG basins synchronously with the emplacement of a granitoid phase was at ca.3285 Ma. No other fabric-forming ductile deformation and metamorphism associated with the development of foliation and mineral lineation is known in the rocks of the Singhbhum Archaean craton subsequent to this event. Formation of the succeeding geological ensembles including the deposition of BIF-bearing Iron Ore Group (IOG) and the emplacement of the post-IOG granitoids at ca.3100 Ma can be described as 'lsnon-orogenic' event taking place during the phase of tectonic quiescence. Supracrustals like the Dhanjori and Simlipal mafic volcanics with intercalated beds of arenite evolved later during the phase of Plume outburst at around 2800 Ma. The end-Archaean intrusion of Newer Dolerite dykes in conjugate sets and the deposition of Kolhan Group in an N-S oriented basin during an E-W stress system mark the culmination of the Archaean crust-building activity in the Singhbhum Archaean craton. [ABSTRACT FROM AUTHOR]

There is an increasing commercial demand for nanoparticles due to their wide applicability in various areas such as electronics, catalysis, chemistry, energy, and medicine. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. In this work, we describe a cost effective and environment friendly technique for green synthesis of silver nanoparticles from 5mM AgNO3 solution through the extract of Argimone maxicana leaf as reducing agent as well as capping agent. Nanoparticles were characterized using UV-Vis absorption spectroscopy, FTIR, XRD and SEM. X-ray diffraction and SEM analysis showed the average particle size of 30 nm as well as revealed their structure. Further these biologically synthesized nanoparticles were found to be highly toxic against different bacterial spp. The most important outcome of this work will be the development of value-added products from Argimone maxicana (a potential weed of India) for biomedical and nanotechnology based industries. This is for the first time that Argimone maxicana weed leaf extract was used for the synthesis of nanoparticles. [ABSTRACT FROM AUTHOR]

Occurrence of rhyolite with spheroidal structure is being reported first time in the Neoproterozoic Malani Igneous Suite (MIS) of Northwestern Peninsular India. MIS consists predominantly of felsic volcanic rocks, felsic plutonic rocks and minor amount of mafic rocks. A spheroidal rhyolite that is shaped like a sphere but is not perfectly round, especially an ellipsoid that is generated by concentric shells of different colours with different compositions revolving around one of its axes. The spheroidal rhyolite is exposed in an area of 200 sq.m. radius in the Nakora area. It is pale yellow to light brown colour, fine grained and consists essentially of quartz, alkali feldspar with accessories of altered ferromagnesian (arfvedsonite) and iron oxides (hematite and magnetite). Spheroidal structure is up to 5 m dimension and shows large number (up to 70) of concentric shells in a few cm thickness surrounding a nuclei. Nakora rhyolites display different hues viz. dark brown, light pink and pink but dark brown rhyolite is associated with pink colour spheroidal rhyolite where their contact is sharp.Geological setting and the petromineralogical characters of spheroidal rhyolite suggest that at early magmatic processes, the supersaturated liquid crystallized rapidly into relatively differential density silicate liquid phases and growth of crystals lead the formation of spheroidal structure in the studied rhyolite. [ABSTRACT FROM AUTHOR]

Abstract: The induced damage in single crystals of Sodium sulphanilate dihydrate (SSDH) irradiated at IUAC, New Delhi with 15MV Pelletron accelerator with 100MeV Ag7+ and 70MeV Li3+ ions has been studied by optical measurements, mechanical hardness measurements, Electrical and ERDA measurements. Optical absorption measurements increase with the increase in fluence. The mechanical hardness of the crystal decreases on irradiation. The dielectric constant of SSDH increases on irradiation. [Copyright &y& Elsevier]

A 2 cm long and 0.8 cm thick, single graphite crystal embedded in quartz, feldspar, and orthopyroxene of a granulite-facies metamorphic rock from southern India exhibits unique homogeneity in δ[sup13]C values along layers parallel to the (0001) surface and smooth unidirectional variation of about 1‰ along the c-crystallographic axis. The fluid-precipitated graphite shows isotope homogeneity indicative of crystal growth along the (0001) plane. The C-isotope data along with the textural features suggest that the formation of graphite initiates in a layer perpendicular to the c-axis, possibly by a spiral growth mechanism. The initial layer is followed layer after layer, until the final stages of graphite growth. A second stage of graphite growth unrestricted by surrounding minerals is inferred from the un-deformed idiomorphic hexagonal form of the overgrown crystals. The C-isotope values in the overgrown rim of the crystal are lowered by about 2‰, suggesting a multistage precipitation. Morphologic and stable isotope studies thus confirm uniform crystal growth of graphite recording an isotope evolution pattern relating to fractionation from a fluid in an infinite reservoir during the main crystal formation. Spiral growth parallel to the (0001) face can explain the perfect uniformity of stable isotope composition in a single layer, whereas the variation across the (0001) surface gives insights into the time-integrated fluid evolution attending the crystal growth. [ABSTRACT FROM AUTHOR]

Studies the crystal structure of julgoldite-Fe³+ from Bombay, India using synchrotron X-ray powder diffraction and [sup57]Fe Mössbauer spectroscopy. Methods; Results; Discussion.

An Indo−U.S. bilateral meeting on Pharmaceutical Cocrystals and Polymorphs was jointly sponsored by the Indo−U.S. Science and Technology Forum (IUSSTF) and the U.S. National Science Foundation. This workshop meeting was held in the historic Mysore city, located about 150 km from Bangalore, on February 8−10, 2009. The American and Indian delegations included editors of Crystal Growth & Design. [ABSTRACT FROM AUTHOR]