Ionic characters of lake water of Bharti promontory,Larsemann Hills,East Antarctica

The Larsemann Hills area represents a unique environmental setting between marine and glacial ecosystems. One of the promontories of this region, named Bharti, depicting similar set up was selected for the study of chemical parameters with special reference to its ionic characters. Water samples from 6 selected lakes of Bharti promontory, Larsemann Hills area were collected during the austral summer of 2004–05 and analysed for major ionic concentration and Total Dissolved Solid (TDS). This study is aimed at understanding the water chemistry of lakes of this island with emphasis on correlation between different ionic concentrations, TDS and its possible causes. The study will provide baseline data that will be useful for planning further studies. Analytical result shows that the water chemistry of these lakes is mainly governed by the lithology, precipitation, drainage and marine environment. Minor contribution of evaporation, has also been observed on the chemistry of one of the lake water. The main source of water for these lakes comes mainly from snow precipitation and its melting. The drainage line mostly goes towards eastern direction for these lakes.     

Wavelength-dispersive X-ray fluorescence spectrometric determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites

Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.     

Rainfall event-based landslide susceptibility zonation mapping

Landslide susceptibility assessment is a major research topic in geo-disaster management. In recent days, various landslide susceptibility and landslide hazard assessment methodologies have been introduced with diverse thoughts of assessment and validation method. Fundamentally, in landslide susceptibility zonation mapping, the susceptibility predictions are generally made in terms of likelihoods and probabilities. An overview of landslide susceptibility zoning practices in the last few years reveals that susceptibility maps have been prepared to have different accuracies and reliabilities. To address this issue, the work in this paper focuses on extreme event-based landslide susceptibility zonation mapping and its evaluation. An ideal terrain of northern Shikoku, Japan, was selected in this study for modeling and event-based landslide susceptibility mapping. Both bivariate and multivariate approaches were considered for the zonation mapping. Two event-based landslide databases were used for the susceptibility analysis, while a relatively new third event landslide database was used in validation. Different event-based susceptibility zonation maps were merged and rectified to prepare a final susceptibility zonation map, which was found to have an accuracy of more than 77 %. The multivariate approach was ascertained to yield a better prediction rate. From this study, it is understood that rectification of susceptibility zonation map is appropriate and reliable when multiple event-based landslide database is available for the same area. The analytical results lead to a significant understanding of improvement in bivariate and multivariate approaches as well as the success rate and prediction rate of the susceptibility maps.     

Adaptive multi‐rate interface: development and experimental verification for real‐time hybrid simulation

Real‐time hybrid simulation (RTHS) is a powerful cyber‐physical technique that is a relatively cost‐effective method to perform global/local system evaluation of structural systems. A major factor that determines the ability of an RTHS to represent true system‐level behavior is the fidelity of the numerical substructure. While the use of higher‐order models increases fidelity of the simulation, it also increases the demand for computational resources. Because RTHS is executed at real‐time, in a conventional RTHS configuration, this increase in computational resources may limit the achievable sampling frequencies and/or introduce delays that can degrade its stability and performance. In this study, the Adaptive Multi‐rate Interface rate‐transitioning and compensation technique is developed to enable the use of more complex numerical models. Such a multi‐rate RTHS is strictly executed at real‐time, although it employs different time steps in the numerical and the physical substructures while including rate‐transitioning to link the components appropriately. Typically, a higher‐order numerical substructure model is solved at larger time intervals, and is coupled with a physical substructure that is driven at smaller time intervals for actuator control purposes. Through a series of simulations, the performance of the AMRI and several existing approaches for multi‐rate RTHS is compared. It is noted that compared with existing methods, AMRI leads to a smaller error, especially at higher ratios of sampling frequency between the numerical and physical substructures and for input signals with high‐frequency content. Further, it does not induce signal chattering at the coupling frequency. The effectiveness of AMRI is also verified experimentally. Copyright © 2016 John Wiley & Sons, Ltd.     

Aerosol light absorption, black carbon, and elemental carbon at the Fresno Supersite, California

Particle light absorption (b_ap), black carbon (BC), and elemental carbon (EC) measurements at the Fresno Supersite during the summer of 2005 were compared to examine the equivalency of current techniques, evaluate filter-based b_ap correction methods, and determine the EC mass absorption efficiency (σ_ap) and the spectral dependence of b_ap. The photoacoustic analyzer (PA) was used as a benchmark for in-situ b_ap. Most b_ap measurement techniques were well correlated (r ≥ 0.95). Unadjusted Aethalometer (AE) and Particle Soot Absorption Photometer (PSAP) b_ap were up to seven times higher than PA b_ap at similar wavelengths because of absorption enhancement by backscattering and multiple scattering. Applying published algorithms to correct for these effects reduced the differences to 24 and 17% for the AE and PSAP, respectively, at 532 nm. The Multi-Angle Absorption Photometer (MAAP), which accounts for backscattering effects, overestimated b_ap relative to the PA by 51%. BC concentrations determined by the AE, MAAP, and Sunset Laboratory semi-continuous carbon analyzer were also highly correlated (r ≥ 0.93) but differed by up to 57%. EC measured with the IMPROVE/STN thermal/optical protocols, and the French two-step thermal protocol agreed to within 29%. Absorption efficiencies determined from PA b_ap and EC measured with different analytical protocols averaged 7.9 ± 1.5, 5.4 ± 1.1, and 2.8 ± 0.6 m²/g at 532, 670, and 1047 nm, respectively. The Angström exponent (α) determined from adjusted AE and PA b_ap ranged from 1.19 to 1.46. The largest values of α occurred during the afternoon hours when the organic fraction of total carbon was highest. Significant biases associated with filter-based measurements of b_ap, BC, and EC are method-specific. Correcting for these biases must take into account differences in aerosol concentration, composition, and sources.     

Geophysical surveys for identifying source and pathways of subsurface water inflow at the Bangur chromite mine,Odisha, India

Geophysical survey was carried out in an effort to solve an underground flooding problem at the Bangur chromite mine of Odisha Mining Corporation Limited, Odisha, India. To identify sources and pathways of the influx, very low-frequency electromagnetic, self-potential and resistivity surveys were performed. Geophysical studies clearly depict a major fracture zone passing through the mine and its connection to a water storage pond. The fracture zone extends further west from the pond to the Salandi River and the Salandi Reservoir. The dip of the delineated fracture zone is around 45° to the N, and it matches with the fault plane exposed in the mine. Since water enters into the mine from the west, the delineated fracture zone is thought to be the main pathway for the inflow. Geophysical studies conclude that the IMFA pond, Salandi River and Salandi Reservoir could be possible sources of water in the mine. To ascertain the source and pathway, tracer testing was conducted at two locations, based on the geophysical survey by the hydrogeological team, but tracer test results were inconclusive. However, the fact remains that the water enters to the mine through the delineated fracture and poses threat in mine operation. Dumping water in nearby pond will again enter in mine with interconnected fractures. Therefore, for safe mining operation, it is proposed to drill a slanted tube well at the delineated fracture and pump out maximum water and discharge the pumped water at canal situated about 2.5 km from the mine.     

Kaveri crater – An impact structure in the Precambrian terrain of southern India

The region to the east of Palghat gap is of low elevation and nearly circular in shape. It forms a part of the Kaveri river basin. The predominantly gneissic terrain is surrounded by the charnockitic hill ranges, prominent among which are Nilgiris and Biligirirangan to the north; and Anaimalai and Kodaikanal to the south. The charnockite massifs have a steep slope facing the circular feature and a gentler slope in the opposite direction. Fractures/faults/shear zones are noticed in many parts. The Bouguer anomaly in the gneissic terrain is elliptical in shape and positive, relative to the surrounding elevated region. The magnetic contours are also elliptical and the magnetic basement is deeper by about one km compared to regions in the periphery. The shallow seismic velocity picture from Chennimalai to Palani indicates a graben structure. The velocity structure also depicts a 4–5 km Moho upwarp near Chennimalai. Junction between the gneissic and charnockitic terrain and even beyond, is marked by the presence of pseudotachylites and breccia. Field and petrographic studies indicate presence of suevite, Planar Deformation Features (PDF), Planar Fractures, diaplectic glass of quartz and plagioclase and spherical inclusion in suevite. These evidences taken together point to an extra-terrestrial impact which created a crater of approximately 120 km in diameter. Several lines of indirect evidences point to Neoproterozoic age for the impact. Kaveri Crater is the fourth largest crater on the surface of the Earth; other larger craters being Vredefort (160 km), Chicxulub (150 km) and Sudbury (130 km).     

Variability of Altimetric Range Correction Parameters over Indian Tropical Region using JASON-1 & JASON-2 Radar Altimeters

Region-specific atmospheric range correction maps are generated over the Indian tropical region from Jason-1 & Jason-2 radar altimeters data. Seasonal and spatial variability of wet tropospheric correction (WTC), ionospheric correction (IC), dry tropospheric correction (DTC), and sea state bias (SSB) correction are analyzed over the Bay of Bengal and the Arabian Sea. Two year atmospheric range correction data from JASON-1 (2008) & JASON-2 altimeters (2009) has been analyzed where each Jason cycle is exactly 9.9156?days repeat. The monthly and yearly mean variation of the range correction parameters has been studied over the Indian continent. For precise study, four different regions were selected as the Region of Interest in the North & South of the Arabian Sea and Bay of Bengal. WTC, Significant Wave Height (SWH), Wind Speed (WS) and SSB show the higher values during monsoon months. The yearly mean WTC over Indian Tropical region was 26.22?cm in 2008 and 26.20?cm in 2009. SSB Correction values mainly depend on the SWH and wind speed. The yearly mean SSB correction over Indian Tropical region was 6.87?cm in 2008 and 7.02?cm in 2009. DTC values are less during monsoon season and it shows a high value in the month of January. The yearly mean DTC over Indian Tropical region was 230.42?cm in 2008 and 230.43?cm in 2009.The IC values mainly depend on frequency and total electron content (TEC) in the ionosphere which further depends on the solar activity. The yearly mean IC over Indian Tropical region was higher in 2008 (2.98?cm) in comparison to mean IC in 2009 (2.29?cm). This study is useful to understand the variability of atmospheric correction parameters especially over Indian continent.