The geology of the manganese ore deposits of talwara,district Banswara,Rajasthan

Talwara (23° 34′: 74° 22′) is a small Manganese-producing locality in the district of Banswara, Rajasthan. From the Banswara Town, Talwara can be reached by a motorable road. In the past, the Manganese ores of the locality have drawn very little attention of the geologists. The ores of Manganese, being associated exclusively with the Aravalli limestone of Rajasthan, occur in the form of scattered masses occupying solution cavities, fissures, etc., in limestone. Aravalli quartzites, conglomerates, phyllites and slates also occur in the vicinity of Talwara. The white limestone with a mosaic structure is of common occurrence and is composed of calcite and dolomite with some magnetite. The impurer varieties of limestone are characterised by the presence of tremolite, hornblende and quartz with a little of biotite. Schistosity is developed only in a calc-amphibole rock having alternating bands of hornblende and limestone. Crush-breccia is noticed occurring in association with manganiferous limestone at a distance of about 2 miles west of Talwara. This breccia might have originated due to severe local crushing of the country-rock. The limestones seemed to be a product of low-grade metamorphism of a calcareous sediment. Fresh ores are generally hard and cavernous but on weathering they become softer and soily. Fragments of unreplaced limestone are occasionally present in the ore-bodies. This limestone has also been replaced by the Manganese ores to a greater or lesser extent, depending on the structural characters of the host rock. The ores are composed largely of massive and colloform cryptomelane. Pyrolusite forms an insignificant part of the ores. There are two generations of cryptomelane, of which, the earlier colloform one is veined by the later generation of cryptomelane. There are also examples of pseudomorphous replacement of limestone by cryptomelane. Most of the pyrolusite was derived from the supergene alteration of cryptomelane. From their nature and mode of occurrence the Manganese ores are classified as outcrop secondary ores formed in cavities in crystalline limestones belonging to the less metamorphosed type of Dharwar.     

Genetic Volterra algebras and their derivations

The present paper is devoted to genetic Volterra algebras. We first study characters of such algebras. We fully describe associative genetic Volterra algebras, in this case all derivations are trivial. In general setting, i.e., when the algebra is not associative, we provide a su?cient condition to get trivial derivation on generic Volterra algebras. Furthermore, we describe all derivations of three dimensional generic Volterra algebras, which allowed us to prove that any local derivation is a derivation of the algebra.     

ChemInform Abstract: Calculational Study of Fluoroammonium and Related Cations and Dications.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Superacidic activation of quinoline and isoquinoline; their reactions with cyclohexane and benzene(1)

Quinoline (1) and isoquinoline (2), upon activation by strong acids, lead to intermediate N,C-diprotonated dications, which are involved in reactions with weak nucleophiles. Thus, 1 and 2 undergo selective ionic hydrogenation with cyclohexane in CF3SO3H-SbF5, HBr-AlBr3-CH2Br2, or HCl-AlCl3-CH2Cl2 acid systems to give their 5,6,7,8-tetrahydro derivatives. They also readily condense with benzene in the presence of HBr-AlBr3 or HCl-AlCl3 to provide 5,6,7,8-tetrahydro-5,7-diphenylquinoline (10) and 5,6,7,8-tetrahydro-6,8-diphenylisoquinoline (12), respectively.     

L p -Version of the Dubins–Savage Inequality and Some Exponential Inequalities

The Dubins–Savage inequality is generalized by using the pth (1<p≤2) conditional moment of the martingale differences. This inequality is further extended under suitable conditions when p>2. Another martingale inequality due to Freedman is also generalized when 0<p≤2. Implications of these inequalities for strong convergence are discussed. Some general exponential inequalities are also given for martingales (supermartingales) under suitable conditions.      

Antioxidant, antimicrobial properties and phenolics of different solvent extracts from bark, leaves and seeds of Pongamia pinnata (L.) Pierre

This study appraises the antioxidant and antimicrobial attributes of various solvent extracts (absolute methanol, aqueous methanol, absolute ethanol, aqueous ethanol, absolute acetone, aqueous acetone, and deionized water) from bark, leaves and seeds of Pongamia pinnata (L.) Pierre. Maximum extraction yield of antioxidant components from bark (16.31%), leaves (11.42%) and seeds (21.51%) of P. pinnata was obtained using aqueous methanol (20:80). Of the extracts tested, the bark extract, obtained with aqueous methanol, exhibited greater levels of total phenolics [6.94 g GAE/100 g dry weight (DW)], total flavonoids (3.44 g CE/100 g DW), inhibition of linoleic acid peroxidation (69.23%) and DPPH radical scavenging activity (IC(50) value, 3.21 μg/mL), followed by leaves and seeds extracts. Bark extract tested against a set of bacterial and fungal strains also revealed the strongest antimicrobial activity with the largest inhibition zone and lowest minimum inhibitory concentration (MIC). HPLC analysis of aqueous methanol extracts from bark, leaves and seeds indicated the presence of protocatechuic, ellagic, ferulic, gallic, gentisic, 4-hydroxybenzoic and 4-hydroxycinnamic acids in bark (1.50-6.70 mg/100 g DW); sorbic, ferulic, gallic, salicylic and p-coumaric acids in leaves (1.18-4.71 mg/100 g DW); vanillic, gallic and tannic acids in seeds (0.52-0.65 mg/100 g DW) as the main phenolic acids. The present investigation concludes that the tested parts of P. pinnata, in particular the bark, have strong potential for the isolation of antioxidant and antimicrobial agents for functional food and pharmaceutical uses.     

Ab initio study of the structures and stabilities of the dimer of ethyl cation, (C(2)H(+)(5))(2) and related C(4)H(10)(2+) isomers.

Ab initio calculations at the MP4(SDTQ)/6-311G//MP2/6-31G level were performed to study the structures and stabilities of the dimer of ethyl cation, (C(2)H(+)(5))(2), and related C(4)H(10)(2+) isomers. Two doubly hydrogen bridged diborane type trans 1 and cis 2 isomers were located as minima. The trans isomer was found to be more favorable than cis isomer by only 0.6 kcal/mol. Several other minima for C(4)H(10)(2+) were also located. However, the global energy minimum corresponds to C-H (C(4) position) protonated 2-butyl cation 10. Structure 10 was computed to be substantially more stable than 1 by 31.7 kcal/mol. The structure 10 was found to be lower in energy than 2-butyl cation 13 by 34.4 kcal/mol.     

Measurement of radon concentrations and their annual effective doses in soils and rocks of Jaintiapur and its adjacent areas,Sylhet, North-east Bangladesh

Journal of Radioanalytical and Nuclear Chemistry - The study investigates the measurement of radon concentration in soils and rocks as a natural tracer for exploring uranium mineralization, first...     

MHD forced convection of MWCNT–Fe3O4/water hybrid nanofluid in a partially heated τ-shaped channel using LBM

Journal of Thermal Analysis and Calorimetry - Forced convection heat transfer of multi-wall carbon nanotubes–iron oxide nanoparticles/water hybrid nanofluid (MWCNT–Fe3O4/water hybrid...