Lithological and tectonic response on catchment characteristics of Rishi Khola, Sikkim, India

Rishi Khola,a sub-watershed of Teesta river,traverses along the Main Central Thrust(MCT)with a multitude of litho units and structural entities.This study examines the impact of tectonic and lithologic controls in configuring the catchment characteristics of Rishi Khola,Sikkim,India.Corrected SRTM 30m DEM and Landsat 8 satellite image have been used for extracting the river network,preparing the sub-catchments,the longitudinal profile and thereby calculating the morphotectonic indices.An aggregated tectonic index(ATI)has been prepared to map the intensity of tectonic perturbations in the fluvial environment using the entropy weightage method(EWM)and Weighted Linear Combination(WLC).The undulating nature of the longitudinal profile with prominent knick points confirms the presence of tectonic disturbances and lithological variations.From all the computed morphotectonic indices and the ATI,it has been evident that the region has experienced surface deformations.When viewed at the entire catchment,the morphotectonic indices suggest ample responses to the tectonic perturbations due to the dominance of lithology-controlled hill slope processes and fluvial erosion.The spatiality of the tectonic sensitiveness is rather concentrated into certain pockets of differential stress field formed due to fault thrusting of the Himalayas.The study chiefly focuses on the peculiarity of the watershed which displays a complex response of tectonic and rock structure;wherein the proposed methodology has been successful in excavating such complex responses around the Himalayan thrusts.

FDTD Simulation of Three Photon Absorption and Realization of NAND Gate with GaAs Wire Waveguide

GaAs has high three photon absorption (3PA) co-efficient at mid-infrared wavelength like2.2mm and waveguides can be formed with this material like silicon nano-wires. It is shown that three-photon-absorption in GaAs wire waveguide can be utilized to form NAND gate. Three-photon-absorption is incorporated in one-dimensional Finite Difference Time Domain (FDTD) equations. The evolution of a probe pulse under the influence of a pump pulse through crossabsorption in a waveguide is investigated using FDTD simulation, where the dominant process is nonlinear three-photon-absorption. Output probe power dependence on input pump power shows that GaAs waveguide NAND gate has higher extinction ratio in comparison to NAND gate using two-photon-absorption in silicon waveguide.

An Exact Analysis of the Fundamental and First Higher Order Mode in Graded Index Fibers with Direct Power Series Method

An exact and fast analytic method based on power series is established to predict the modal field distributions, Petermann-2 spot size, the normalized propagation constant corresponding to fundamental and first higher order mode in graded index fibers with any arbitrary power law profile. The variation of normalized cut-off frequencies of some LPlm modes in graded index fibers with different profile exponents are also shown here and an empirical relation between them is determined.

How Does the Blue C Stock Vary in Restored and Degraded Wetlands Across Land Cover Mosaics? Evidences from Medinipur Coastal Plain, India

Coastal wetlands are of paramount importance as major reservoirs of blue carbon(C),playing a crucial role in providing nature-based solutions to mitigate climatic changes.This research aimed to analyse the dynamics of total blue C(TBC)and its components;viz.soil organic C(SOC),below ground C,and above ground C;as well how they are influenced by land use/land cover(LULC)categories and wetland situations.Subsequently,study were identified as one restored wetland and another degraded wetland in the Medinipur Coastal Plain,India.The LULC categories were analyzed using Pleiades 1A and 1B satellite imagery,corresponding to the restored and degraded wetland,respectively.The quantification of SOC was based on point-specific sample data collected from both wetlands(nr=250;nd=84).Above ground biomass(AGB)was appraised employing allometric relationships involving field-measured dendrometric variables.Below ground biomass values were calculated using indirect allometric equations that take into account the AGB values.Integrating all the components,TBC stock of the restored and degraded wetlands were estimated at 246710.91 Mg and 7865.49 Mg,respectively.In the restored wetland,dense mangrove and open mangrove exhibited higher concentrations of blue C components,while other LULC categories demonstrated moderate to low densities.In the degraded wetland,the open mangrove category rechigh densities of C pools,whereas herbaceous vegetation,bare earth and sand,and waterbody exhibited lower concentrations.The results portrayed significant disparities(P<0.05)in blue C pools among different LULC categories in both wetlands.Furthermore,it was evident that wetland type and LULC category had notable(P<0.001)impacts on TBC dynamics,both individually and in combination.Overall,this research may aid in effective management of coastal wetlands as blue C sinks,emphasizing their significance as essential elements of climate mitigation strategies.