Snow cover variability and trend over Hindu Kush Himalayan region using MODIS and SRTM data

Snow cover changes has a direct bearing on the regional and global energy and water cycles, and the change in Earth's climate condition The study of long term altitudinal (spatial and temporal, 2000–2017) in the coverage of snow and glaciers in one of the world’s largest mountainous region, the Hindu Kush Himalayan (HKH) region including Tibet have been studied using remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra (at 5 km grid resolution). Terra provided a unique opportunity to study zonal and hypsographic changes in the intra-annual (growing season and melting season) and inter-annual variations of snow and glacial cover over the HKH region (2000–2017). The zonal and altitudinal (hypsographic) analyses were carried out for melting-season and accumulating-season. The altitude-wise linear trend analysis (Pearson’s) of snow cover, shown as a hypsographic curve, clearly indicate a major decline in snow cover (average of 5 % or more, at 100 m interval aggregates) between 4000–4500 m and 5500–6000 m altitudes, which is consistent with the median trend (Theil-Sen, TS) and the monotonic trend (Mann-Kendall statistics, MK) analysis. The regions and altitudes where major and statistically significant increase (10 to 30 %) or decrease (−10 to −30 %) in snow cover are identified. The extrapolation of the altitude-wise linear trend shows that it may take between ~74 to 7900 year (for 3001–6000 m and 6000–7000 m altitude zones respectively) for mean snow cover to decline approximately 25 % in the HKH region, assuming no-change in other parameters) that affect the snow cover.

Electrical and Thermal Conductivity of Cyclic Natural Rubber/Graphene Nanocomposite Prepared by Solution Mixing Technique

Thermal and electrical conductivity studies of Cyclic Natural Rubber nanocomposite with graphene 1 and 2 phr (G1 and G2) and modified 1 and 2 graphenes (mG1 and mG2) have been carried out. Graphene was activated with cetrimonium bromide (CTAB), was isolated from Sawahlunto coal (Bb) by the Hummer modification method. The nanocomposite was fabricated through the mixing solution method using Xylena as a solvent. The characterizations of nanocomposites which were performed by Fourier Transform Infrared (FT-IR) and X-Ray Diffraction (XRD) reveals an interaction between graphene, CTAB and the CNR matrix. Furthermore, Scanning Electron Magnetic (SEM) and Transmission Electron Microscopy (TEM) indicate the particle size to be smaller and particle distribution is more in accordance with CTAB. Thermal analysis of nanocomposites using Differential Scanning Calorimeter (DSC) showed an increase in thermal conductivity from 3.0084 W/mK to 3.5569 W/mK. Analysis of electrical conductivity using the Two-Point Probe shows 2 phr mG (mG2) capable of increasing electrical conductivity from 0.1170 × 10–4 S/cm to 0.2994 × 10-4 S/cm.

Intrinsic diagram of sheet metal forming limits for arbitrary strain paths

Localized necking in sheets under biaxial tension is analysed by an Marciniak—Kuczynski localization approach (MK-analysis) along with a new plane-stress criterion. Analysis is developed for a rigid viscoplastic behaviour based on flow-theory of plasticity. The model is introduced in numerical calculations to determine forming limits to ductility under linear and non-linear strain paths. However, the results are presented in a new diagram that represent the effective strain as a function of the current strain-rate ratio. A comparison with classical forming limit diagrams shows the intrinsic character of the new diagram.