ALBERT

Description: The Indian subcontinent comprises of geological terranes of varied age and structural character. In this study, we provide new constraints to existing crustal models by inverting the P-to-s receiver functions (RFs) at 317 broadband seismic stations. Inversion results fill crucial gaps in existing velocity models (CRUST1.0 and SEAPS) by capturing regions which are less represented. The final model produced is much more heterogeneous and is able to capture the structural variations between closely spaced seismic stations. In comparison to the global models, major differences are seen for seismic stations located over various rift zones (e.g. Godavari, Narmada and Cambay) and those close to the coastal regions where transition from oceanic to continental crust is expected to create drastic changes in the crustal configuration. Seismic images are produced along various profiles using 49682 individual RFs recorded at 442 seismic stations. Lateral variations captured using migrated images across the Himalayan collisional front revealed the hitherto elusive southern extent of the Moho and intracrustal features south of the Main Central Thrust (MCT). Poisson's ratio and crustal thickness estimates obtained using H- k stacking technique and inversion of RFs are grossly similar lending credence to the robustness of inversions. An updated crustal thickness map produced using 1525 individual data points from controlled source seismics and RFs reveals a a) thickened crust (〉55 km) at the boundary of Dharwar Craton and Southern Granulite Terrain b) clear difference in crustal thickness estimates between Eastern Dharwar Craton and Western Dharwar Craton c) thinner crust beneath Cambay Basin between southwest Deccan Volcanic Province and Delhi Aravalli Fold Belt d) thinner crust (〈35 km) beneath Bengal Basin e) thicker crust (〉40 km) beneath paleo-rift zones like Narmada Son Lineament and Godavari Graben f) very thick crust beneath central Tibet (〉 65 km) with maximum lateral variations along the Himalayan collision front.

Description: In this work, the effect of gradual addition of Al 2 O 3 substituting SiO 2 on the structural, thermal and mechanical properties of SiO 2 -BaF 2 -K 2 O-GdF 3 -Sb 2 O 3 based oxyfluoride glasses have been studied. The X-ray diffraction (XRD) patterns and differential scanning calorimetric (DSC) curves indicate that there is a distinct primary crystallization corresponding to BaGdF 5 phase formation in the samples without (0AlG) and with 5 mol% substitution of Al 2 O 3 (5AlG) while the sample with 10 mol% of Al 2 O 3 (10AlG) does not show such crystallization event. Further, the activation energy ( E a ) for fluoride crystal formation is higher for the 5AlG in comparison to the 0AlG glass as determined by Kissinger, Augis-Bennett and Ozawa models. Fourier transform infrared (FTIR) and Raman spectroscopy analysis confirmed the structural modification with the gradual addition of Al 2 O 3 in the glass matrix revealing dominant presence of AlO 4 tetrahedral units in 10AlG sample unlike in 5AlG sample which exhibited the manifestation of AlO 6 units. Such structural variation has further been substantiated from the estimated elastic properties like Young's modulus ( E ), shear modulus ( G ), bulk modulus ( K ), longitudinal modulus ( L ) and mean ultrasonic velocity ( U m ) by showing a decrease for 5AlG sample in comparison to 0AlG sample followed by subsequent increase for 10AlG sample. This article is protected by copyright. All rights reserved.

Description: Scale- and location-dependent relationships between soil water content (SWC) and individual environmental factors have been widely explored. SWC is controlled by multiple factors concurrently; however, the multivariate relationship is rarely explored at different scales and locations. Multivariate controls of SWC at different scales and locations in two seasons within a hummocky landscape of North America were identified using bivariate wavelet coherency and multiple wavelet coherence. Results showed that depth to CaCO 3 layer which was correlated with elevation over all locations at scales of 36–144 m and cos(aspect) provided the best individual factor for explaining SWC variations in the spring (May 2) and summer (August 23), respectively. Although spatial patterns of SWC were temporally stable, different topographic indices affected spatial distribution of SWC in different seasons (elevation in spring and aspect in summer) due to different dominating hydrological processes. These varying hydrological processes also resulted in the distinct role of soil organic carbon (SOC) content in different seasons: a positive correlation in the spring and a negative correlation in the summer. Multiple wavelet coherence identified a combination of depth to CaCO 3 layer and SOC in spring and a combination of cos(aspect) and SOC in summer that controlled SWC at different scales and locations, respectively. This indicated a combined effect of soil and topographic properties on SWC distribution and a clear need for these two factors in developing scale-dependent prediction of SWC in the hummocky landscape of North America.

Description: ABSTRACT El Niño Southern Oscillation (ENSO) and Indian Ocean dipole (IOD) play an important role in determining the weather pattern over the Indian subcontinent region. The role of ENSO and IOD on the occurrence of tropical cyclone activity during post-monsoon season (October–December) over the Bay of Bengal (BoB) has been investigated through an objective analysis of observed data for the period of 1990–2015. Accumulated cyclone energy (ACE) index is an important measure of tropical cyclone activity over a basin for a defined period of time. Sea-surface temperature (SST) anomalies in the Niño 3.4 region (oceanic Niño index) is negatively correlated at 95% confidence level of significance with ACE over the BoB during post-monsoon season. Positive phase of IOD has negative impact on the tropical cyclone formation over the BoB. The ACE has large inter-annual variability with coefficient of variation 124% for tropical cyclone activity over BoB during post-monsoon season. Frequency distribution of annual ACE values for post-monsoon season over the BoB indicated that cold phases of ENSO along with negative IOD index values are the most favourable for development of tropical cyclone over the BoB. Principle component regression (PCR) model developed by cross-verification method based on training period data for 1990–2013 and ONI and DMI values of different lag periods as predictors is found to be functional for both deterministic and probabilistic prediction of ACE values of post-monsoon season. Above- and below-normal TC activities were observed in 2014 and 2015, respectively, which have been well predicted by the PCR model. Cold phases of ENSO along with negative IOD index values are most favourable for development of tropical cyclone over the Bay of Bengal. A principle component regression (PCR) model ONI and DMI as predictors is found to be functional for both deterministic and probabilistic prediction of post-monsoon tropical cyclone activity over Bay of Bengal. Forecast and cross-validated hindcasts values of ACE from PCR model and observed values of ACE during 1990–2015.

Description: Acidification of manure, digestate and their processed derivatives has been proposed as a technique to, amongst others, mitigate ammonia emissions related to application in the field. The current study investigated whether acidification of (1) pig slurry (PS), (2) liquid fraction of pig slurry (LFPS), (3) digestate (DIG), and (4) liquid fraction of digestate (LFDIG) increases their nitrogen (N) fertilizer replacement value (NFRV) as compared to non-acidified counterparts, a synthetic N fertilizer (calcium ammonium nitrate; CAN) and an unfertilized control. Product performance was evaluated from the perspective of (1) crop development (yield, nutrient uptake, and crop quality assessment) via a pot experiment with Lactuca sativa L. and (2) soil N dynamics [net N release (N rel,net ) and net N mineralization] via a soil incubation experiment. Crop yield of pots receiving bio-based fertilizers performed ‘on par' with CAN as compared to unfertilized control, implying that bio-based fertilizers derived from digestate or manure could potentially play a role in replacing synthetic N fertilizers. However, our findings also suggest that acidification did not result in an increased use efficiency of applied N. NFRVs of acidified products were below those of non-acidified products and CAN, with crop yield on average 6–13% and 11–18% lower compared to non-acidified products and the CAN treatment, respectively. A possible explanation for lower performance as compared to non-acidified products could be an inhibitory delay in the N rel,net , which in our experimental design proved to be negative for crops with short production cycles. This pattern was revealed in the incubation experiments in which N rel,net in acidified products remained below that of non-acidified, in this study tentatively attributed to immobilization of mineral N. However, this negative effect on N availability should be reaffirmed in crops with longer production cycles. Finally, some interesting findings with regard to plant composition also warrant further in-depth investigation, e.g ., Zn uptake by lettuce in acidified treatments was significantly higher than that of non-acidified treatments. This implies that product pre-treatment may play a future role in biofortification and amelioration of (trace) element composition of crops (arguably for crops with longer production cycles). Improving crop nutritional value by increased uptake of micronutrients is receiving increasing attention.

Description: ABSTRACT In order to understand the climatic implications of atmospheric aerosols, top of atmosphere (TOA) shortwave (SW, 0.3–5 µm) fluxes and aerosol optical depth (AOD) at 550 nm retrieved simultaneously by clouds and the earth's radiant energy system (CERES) and moderate resolution imaging spectroradiometer (MODIS) instruments, respectively, are analysed over North-East India and its adjoining areas for the period July 2002–December 2013. The aerosol-free TOA flux obtained by establishing the linear regression between CERES SW TOA fluxes and MODIS AODs exhibits strong seasonality with peak values in monsoon and minimum in winter. Same seasonality is captured by the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model, but with difference in absolute values. SBDART code is used to extend instantaneous radiative forcing estimates into 24-h averages. AOD over the North East India region with complex terrain shows altitudinal variation with maximum value at the lowest elevation site Dhaka and minimum value at the high-altitude locations Shillong and Aizwal. In general, strong seasonality in AOD is observed with a peak in pre-monsoon (March–May) and dip in post-monsoon (October–November) at all the locations. The direct instantaneous TOA shortwave aerosol radiative forcing (SWARF) shows maximum values in pre-monsoon over all the locations except at Guwahati, Banmauk, Aizawl, and Shillong. The lowest value of instantaneous SWARF is observed in post-monsoon except at Banmauk and Shillong. Climatologically TOA diurnally averaged SWARF varies between −6.95 W m −2 in Aizawl to −20.39 W m −2 in Shillong. In general, the TOA SW forcing efficiency is highest in monsoon at all the locations. The radiative forcing efficiency is found to be less negative when surface reflectance increases.

Description: Development of Aluminum Nitride (AlN) – Single Walled Carbon Nanotube (SWCNT) ceramic-matrix composite containing 1 to 6 vol% SWCNT by hot pressing has been reported in this article. The composites containing 6 vol% SWCNT are dense (~99% Relative Density) and show high dc electrical conductivity (200 Sm −1 ) and thermal conductivity (62 Wm −1 K −1 ) at room temperature. SWCNTs contain mostly metallic variety tubes obtained by controlled processing of the pristine tubes before incorporation into the ceramic matrix. Raman spectroscopy and field emission scanning electron microscopy (FESEM) of the fracture surface of the samples show the excellent survivability of the SWCNTs even after high temperature hot pressing. The results indicate the possibility of preparation of AlN nanocomposite for use in plasma devices and electromagnetic shielding. This article is protected by copyright. All rights reserved.