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Dynamics of stock market cycles: a systematic Introspection from some recent evidences
Chakrabarti, Gagari
Historically, stock-market cycles, crashes and the resultant panic have ended in ultimate devastating impact on the rest of the economy. Proper macroeconomic management and accomplishing macroeconomic objectives require both in terms of depth and width, sound health of the financial system. A fragile financial sector is often identified as the prime factor in generating and aggravating crises. Moreover, with extensive trade and financial integration, crises in one market immediately affect others through dynamic linkages among markets or “contagion”. Hence, at this juncture, inquiry into market dynamics becomes crucial. Present study intervenes here focusing on the two past significant stock-market crises namely, the dotcom bubble and the global melt-down of 2007-08. Around the five sub-phases the study found significant volatility transmission channels primarily through past-volatility impacts. In recent era of fluctuation and instability, the stock-markets have become more integrated where innovation and volatility impacts are strong and significantly positive. The news-impacts, however, are always less intense than past-volatility impacts. Moreover, even with increasing financial integration, there remains a basis for global portfolio diversification
Graphene Oxide based polyvalent metal oxide nanocomposite: preparation, characterization and efficiency evaluation on arsenic and fluoride removal from contaminated water
Ghosh, Uday Chand; Palani, Sasi Kumar
Iron-Aluminum mixed oxide (HIAMO) and various proportions of Graphene oxide (GO)-incorporated iron-aluminium mixed oxide (GIAMO-1 to GIAMO-6) composite materials were prepared and characterized by several modern instrumental techniques such as FTIR, XRD, TGA/DTA, SEM, TEM, and Raman spectroscopy. The prepared materials particularly GIAMO-1 and GIAMO-3 were employed for adsorption of the arsenic and fluoride from aqueous solutions respectively.
GIAMO-1 shows very good (92–95%) arsenic(III) removal efficiency from water, which is 30–35% higher than pristine iron-aluminium oxide (HIAMO) from an aqueous solution (5.0 mg AsIII•L−1) at pH 7.0 (± 0.2) and 303 K.The kinetic data agree more closely with pseudo-first order equation (R2 = 0.98–0.99) than pseudo-second order equation (R2 = 0.92–0.93). The equilibrium data describe the Langmuir isotherm (R2 = 0.97–0.98) better than the Freundlich isotherm (R2 = 0.91–0.92), showing the Langmuir monolayer capacity 42.2836 mg•g−1 at 293 K which drops to 24.9170 mg•g−1 at 313 K.
Similarly, GIAMO-3 showed highest fluoride adsorption capacity (qe, mg g−1) at pH ∼ 7.0 and ambient temperature. The material showed an increase of qe with pH up to ∼5.5, and then reduced. Kinetically, fluoride adsorption took place obeying the pseudo-second order model. The Langmuir adsorption isotherm described the equilibrium data best with monolayer adsorption capacities 22.13, 22.90 and 27.75 mg g−1 at 288, 308 and 318 K, respectively, indicating endothermic nature of adsorption process, which was also confirmed from the thermodynamic analysis of equilibrium data. Fluoride adsorption efficiency of HIAGO had been predicted by modelling a single stage batch adsorber design parameters.
Synthesis and Characterization of Polymer Grafted Carbon Nano Particles
Chatterjee, Dhruba Prosad
The present thesis entitled “Synthesis and Characterization of Polymer Grafted Carbon Nano Particles” deals with the synthesis and characterization of controlled and covalently grafted nanostructured carbon material-g-polyaniline nano composites. A thorough analysis of their structure, morphology and electrochemical properties are presented. The work is carried out at the Department of Chemistry, Presidency University, Kolkata 700073 India, under the supervision of Dr. Dhruba Prosad Chatterjee.
The thesis comprises of five chapters. Chapter 1 deals with a brief introduction of carbon nano particles; their classification, synthesis, their composites with different polymers and their application in electronics, biomedical, energy application. Due to their high surface area and porosity, carbon nano materials are capable of showing electrochemical double layer capacitance (EDLC), whereas conducting polymers like polyaniline, polythiophene and polypyrrole show pseudocapacitance. Achieving their best of synergistic effect via covalent bonding hence, improvement in electrochemical properties is the main focus of my research. Chapter 2 describes controlled polymerization of aniline on spherical carbon nano dots (CND) obtained from oxidation followed by size separation from cheap raw material like candle soot, resulting in distinguishable morphology between controlled and uncontrolled product with much improved electrochemical property of the former. Chapter 3 illustrates the synthesis of covalently attached graphene oxide-g-polyaniline nano composites having hierarchical nano structuring of one dimensional (1D) polyaniline nano cylinders over two dimensional (2D) graphene oxide surfaces along with formation of unique microflower or ‘sea urchin’ like highly porous three dimensional (3D) microstructures resulting in superior electrochemical properties than non covalent product. Chapter 4 investigates synthesis of covalently attached GO-g-PANI chiral nanocomposites seeded by oligomeric aniline attached GO sheets, which shows better electrochemical properties compared to non covalently attached composite with much inferior degree of PANI chain chirality. A summary of the research work along with the future prospects obtained from this thesis are presented in Chapter 5.
Stratigraphy and Nature of uranium mineralization from Precambrian Basement Granitoid -Srisailam Formation contact around Chitrial area, Cuddapah Basin, Telangana
Ghosh, Gautam; Bose, Sankar
The biotite rich granitoid rocks exposed around Chitrial village varies in character from a porphyritic to massive granite to gneiss or mylonite with characteristic foliations defined by alternate quartzo-feldspathic and biotite rich layers in the latter units. It is intruded by ca. 1.9-1.8 Ga age mafic dyke sets and is overlain by Mesoproterozoic Srisailam Formation rocks of the Cuddapah Supergroup represented by an arenaceous gritty or pebbly sandstone interspersed with thin shale and siltstone horizons. The granitoid locally becomes uranium-rich near its contact with the overlying Srisailam Formation rocks. The present work encompasses stratigraphic, petrological, geochemical and geochronological analyses of the granitoids and accompanying supracrustals with special emphasis on nature and localization of uranium mineralization.
Major element geochemical data characterize the granitoid rocks as monzogranites and alkali feldspar granite and the cover rocks as quartz arenites. The trace and rare earth element data were used to identify the protolith history of the granitoid rocks as well as about the nature of provenance of the cover sediments. The geochemical data further provide clues regarding probable tectonic and geodynamic setting of these rocks. A marked enrichment in U, Th and REE (particularly LREE) content of the granitoids has been noted. The overall REE pattern suggests a similar source for all the granitoid types. Several tectonic discrimination diagrams suggest a volcanic arc tectonic setting for these rocks. The recycled mature quartzose cover rocks show distinctly similar geochemical characteristics as the granitoids suggesting a granitoid/felsic source of mature continental provenance. REE patterns of the basement granite and the cover sandstone show similar variation which represents that the derivation of the sediments could be from the underlying basement granite.
Recent exploration programme by Atomic Minerals Directorate for Exploration and Research (AMDER) has led to the discovery of a number of potential radioactive mineralized zones in the northwestern part of the Cuddapah basin such as around the Chitrial area. Uranium bearing minerals are intimately associated with sulphide rich minerals within the basement granitoids of the area. There is ample evidence of hydrothermal activity straddling across the unconformity surface which includes- (1) development of fracture filling veins of various dimensions comprising quartz, quartz-epidote, quartz-chlorite or pyrite, (2) hydrothermal alteration of granitoids adjacent to these veins resulting in chloritization and sericitization and (3) epigenetic uranium mineralization in micro-fractures and inter-granular spaces within granitoids. Evidence of uranium mineralization within the cover rocks is comparatively less. In the uraniferous zones in granitoid and overlying quartzite, pitchblende and coffinite are the main uranium phases occurring in micro-fractures and inter-granular spaces of host rock, often in association with pyrite. Depending upon micro-textural data, the paragenetic history of the mineralization has been divided into seven stages in the present study.
U-Pb zircon radiometric dating of the basement granitoids reveals that the main tectonothermal event took place in Chitrial area between ca. 2535 Ma and 2519 Ma. Granitoid samples including the grey massive variety, pink granite, granite gneiss, foliated granite and alkali feldspar granite show emplacement ages of 2525±20 Ma, 2519±12 Ma, 2524±18 Ma, 2514±22 Ma and 2524±20 Ma respectively. Hence, it can be concluded that major tectonothermal event affected these rocks of the study area around 2535 to 2514 Ma. Probability density plot of weighted mean ages for the sample CT206 (granite gneiss) shows a strong peak at ca. 2465 Ma while the sample CT207 (foliated granite) shows another strong peak at ca. 2455 Ma which may be related to a second phase of tectonothermal event. U-Pb zircon detrital age of the cover rocks of the Chitrial area gives major cluster ages at ca. 2468 and 2488 Ma that may be correlated with this second tectonothermal event. From these rocks, diagnostic detrital zircons show age peaks at ca. 2520 Ma, 3000 Ma and 3200 Ma, which correspond to the established emplacement ages of the basement granitoid plutons in the Eastern Dharwar Craton. Younger dates are discordant with a lower intercept ages of near 200 Ma in the Wetherill concordia. Older zircon cores with spot data ranging from 2636±28 Ma to 3200±7 Ma are interpreted as grains inherited from the crustal source region or from the wall-rock of the granite intrusion. From the detrital zircon data, it can be inferred that source of the sediments is proximal. EPMA chemical dates of uraninites from the drill core sample 226B shows that the area underwent several episodes of hydrothermal activity, which have left their imprints on the isotope systematics of uraninite. Thus the younger ages furnished by U-Pb zircon radiometric dating of uranium rich in-situ zircon grains of the granite drill core sample (289Av) shows a group age of 172 Ma, possibly related to the much younger tectonothermal event.
From this study, it is concluded that the Chitrial granitoids are ‘S’ type in character and formed by intracrustal melting of the deeply buried clastic sediments and subsequent incubational heating. It also implies crustal recycling could be the likely mechanism for granite magmatism during ca. 2535-2514 Ma. Uranium mineralization in the granite was influenced by increased fracture volume in the rocks and was controlled by oxygen fugacity in the ore-bearing hydrothermal fluid. This mineralization is related with the later stage fracture reactivation of the Eastern Dharwar Craton during a major younger tectonic activity.