Present status of the geochronology of the early Precambrian of South India

The present status of Precambrian geochronology of South India was summarized. Support was offered for Raith's conclusion of an extensive 3.3 to 3.4-Ga tonalite-forming event. Evidence that the Sargur supracrustal sequence predates this event, however, remains equivocal. The only reliably dated supracrustal rocks are the similar to 3.0-Ga Chitradurga acid volcanics, and these are separated from the older Bababudan supracrustals by a major gneiss-forming event. A major unsolved problem relates to the timing of the Sargur supracrustals in relation to the basal units of the Dharwar succession. An appeal was made for more geochronological work on South Indian samples

Mid-infrared Gas Sensing Using Graphene Plasmons Tuned by Reversible Chemical Doping

Highly confined plasmon modes in nanostructured graphene can be used to detect tiny quantities of biological and gas molecules. In biosensing, a specific biomarker can be concentrated close to graphene, where the optical field is enhanced, by using an ad-hoc functional layer (e.g., antibodies). Inspired by this approach, in this paper we exploit the chemical and gas adsorption properties of an ultrathin polymer layer deposited on a nanostructured graphene surface to demonstrate a new gas sensing scheme. A proof-of-concept experiment using polyethylenimine (PEI) that is chemically reactive to CO2 molecules is presented. Upon CO2 adsorption, the sensor optical response changes because of PEI vibrational modes enhancement and shift in plasmon resonance, the latter related to polymer-induced doping of graphene. We show that the change in optical response is reversed during CO2 desorption. The demonstrated limit of detection (LOD) of 390 ppm corresponds to the lowest value detectable in ambient atmosphere, which can be lowered by operating in vacuum. By using specific adsorption polymers, the proposed sensing scheme can be easily extended to other relevant gases, for example, volatile organic compounds.Peer ReviewedPostprint (published version

Studies on Raschel knotless netting

Production of knotless webbings is of recent origin in India. An attempt has been made to evaluate the quality of the product consequent to its introduction in the fishing industry. A method has been presented to fix up yarn specification for Raschel knotless nettings equivalent to a given knotted netting

Synthetic fibres for fishing gear

A variety of synthetic fibres are at present in use as fishing gear material, the earliest one being the polyvinyl chloride group introduced for traps in 1936 (von. Brandt 1957). Since then synthetic fibres became increasingly popular among the advanced fishing nations of the world. The latest synthetic fibre which has been successfully used in fishing is polypropylene developed in Italy in 1954

Age of the Lower Vindhyan sediments, Central India

The basic issue raised by the two simultaneous and sensational reports in 1998 of body fossil evidence (worm tracks and small shelly fauna, respectively) of multicellular life in the Lower Vindhyan sediments, is the true age of the latter. Is the true age Mid-Proterozoic as believed so far, on limited geochronological data and assumed by Seilacher et al.? Or is it only Early Cambrian, as was argued by Azmi and supported by a single preliminary Ar-Ar age of 617 Ma measured soon after the reports? Although both the fossil evidences are now equivocal, the basic issue remains. We report consistent Rb-Sr ages for glauconies from the Lower Vindhyan sediments (Semri Group) near Chitrakut, which constrain the onset of the earliest Vindhyan sedimentation to not later than 1600 Ma. Considering other available chronological constraints, the Vindhyan basin is likely to preserve a rare, very long and least disturbed record of Pre-cambrian sedimentation

Advances in the Value Addition to Foods-recent Trends

Value addition to foods may be done by several ways. It could be done by the use of preservative, food ingredients capable of eliciting functionalities and by fortification using micronutrients. There are novel and emerging food processing technologies that are possible to preserve the ingredients in the food intact. The shelf life enhancement of the processed food can be done by adapting newer packaging technologies. Food processing industries in many of the countries across the world generates huge quantity of by-products that can be put into use by value addition. These by-products have less use and create considerable environmental pollution. The by-products of the fruits, vegetables, etc. may be used for value addition adapting commercially viable approaches. Fermented foods are value added foods that could be developed using novel starters. It is also important to note the regulatory aspects of foods whenever the foods are preserved b y value additio

A Hierarchical Spatio-Temporal Statistical Model Motivated by Glaciology

In this paper, we extend and analyze a Bayesian hierarchical spatio-temporal model for physical systems. A novelty is to model the discrepancy between the output of a computer simulator for a physical process and the actual process values with a multivariate random walk. For computational efficiency, linear algebra for bandwidth limited matrices is utilized, and first-order emulator inference allows for the fast emulation of a numerical partial differential equation (PDE) solver. A test scenario from a physical system motivated by glaciology is used to examine the speed and accuracy of the computational methods used, in addition to the viability of modeling assumptions. We conclude by discussing how the model and associated methodology can be applied in other physical contexts besides glaciology.Comment: Revision accepted for publication by the Journal of Agricultural, Biological, and Environmental Statistic