Damage Estimation using Shock Zones: A case study of Amphan tropical cyclone

The tropical cyclone affects millions of people living in the coastal regions. The changing climate has led to an increased intensity and frequency of cyclones, therefore increasing the damage caused to people, the environment, and property. The Bay of Bengal is most prone to tropical cyclones, which affects Bangladesh and the eastern coastal region of India due to geographical proximity. Hence, a comprehensive understanding of the inundation damage and intensity caused becomes essential to focus the relief efforts on the affected districts. This study identified the shock zone and assessed the inundation associated damage caused by recent cyclone Amphan in the area of Bangladesh and West Bengal in India. The shock zonation was based on the track of cyclones, cyclone wind speed zones, elevation, wind impact potentiality, and agricultural population area. The identification of the affected area was done using integrated Landsat and SAR data, and economic damage cost was assessed using the Asian Development Bank’s (ADB) Unit price approach. The total people affected due to inundation are 2.4 million in India and 1.4 million in Bangladesh and the damage totaled up to 5.4 million USD. The results of this study can be used by concerned authorities to identify the shock zones and be used for rapid assessment of the damages.

Damage Estimation using Shock Zones: A case study of Amphan tropical cyclone

The tropical cyclone affects millions of people living in the coastal regions. The changing climate has led to an increased intensity and frequency of cyclones, therefore increasing the damage caused to people, the environment, and property. The Bay of Bengal is most prone to tropical cyclones, which affects Bangladesh and the eastern coastal region of India due to geographical proximity. Hence, a comprehensive understanding of the inundation damage and intensity caused becomes essential to focus the relief efforts on the affected districts. This study identified the shock zone and assessed the inundation associated damage caused by recent cyclone Amphan in the area of Bangladesh and West Bengal in India. The shock zonation was based on the track of cyclones, cyclone wind speed zones, elevation, wind impact potentiality, and agricultural population area. The identification of the affected area was done using integrated Landsat and SAR data, and economic damage cost was assessed using the Asian Development Bank’s (ADB) Unit price approach. The total people affected due to inundation are 2.4 million in India and 1.4 million in Bangladesh and the damage totaled up to 5.4 million USD. The results of this study can be used by concerned authorities to identify the shock zones and be used for rapid assessment of the damages.

CHANGES IN THE MICROSTRUCTURE AND MICROHARDNESS OF 65G STEEL AFTER THERMAL HARDENING AND SURFACING WITH A LOW-CARBON ELECTRODE

When reinforcing the surfaces of the working bodies of tillage tools, they are surfaced with electrodes with a low-carbon rod. The surface in contact with the soil is not subjected to heat treatment. Recently, thermal hardening of local parts has been used. (Research purpose) The research purpose is in studying the transformation of the microstructure of 65G heat-strengthened steel deposited by an electrode with a low-carbon rod, as well as the specifics of the microhardness distribution in this section. (Materials and methods) Investigated in the cross- section of the structure of the deposited area by the standard method, consisting in the preparation of microsections, etching and directly microanalysis. (Results and discussion) The transformation of the microstructure of heat-strengthened steel 65G deposited by an electrode with a low-carbon rod is complex due to the specificity and versatility of the phase transformations that occur during its formation. The microhardness distribution plot in the cross-section of the surfacing area has a complex configuration, determined by the variety of structural components, the presence of deformation processes during crystallization and solidification, and the presence of preliminary thermal hardening of the base metal. (Conclusions) Increased values of the hardness of individual areas contribute to an increase in the abrasive wear resistance of the part. The presence of the fusion zone ensures the resistance of the deposited area to cracking. The zone of thermal influence has four clearly distinguishable areas: the drop in microhardness; the stable values according to the Vickers method; the near-shock zone; the fusion zone. The microhardness of the weld surface of the cushion is 410 Vickers or 42 Rockwell, which creates conditions for increasing the wear resistance of the surface friction. The use of electrodes with a low-carbon rod is advisable when conducting surfacing reinforcement of heat-strengthened steels.

CHANGES IN THE MICROSTRUCTURE AND MICROHARDNESS OF 65G STEEL AFTER THERMAL HARDENING AND SURFACING WITH A LOW-CARBON ELECTRODE

When reinforcing the surfaces of the working bodies of tillage tools, they are surfaced with electrodes with a low-carbon rod. The surface in contact with the soil is not subjected to heat treatment. Recently, thermal hardening of local parts has been used. (Research purpose) The research purpose is in studying the transformation of the microstructure of 65G heat-strengthened steel deposited by an electrode with a low-carbon rod, as well as the specifics of the microhardness distribution in this section. (Materials and methods) Investigated in the cross-section of the structure of the deposited area by the standard method, consisting in the preparation of microsections, etching and directly microanalysis. (Results and discussion) The transformation of the microstructure of heat-strengthened steel 65G deposited by an electrode with a low-carbon rod is complex due to the specificity and versatility of the phase transformations that occur during its formation. The microhardness distribution plot in the cross-section of the surfacing area has a complex configuration, determined by the variety of structural components, the presence of deformation processes during crystallization and solidification, and the presence of preliminary thermal hardening of the base metal. (Conclusions) Increased values of the hardness of individual areas contribute to an increase in the abrasive wear resistance of the part. The presence of the fusion zone ensures the resistance of the deposited area to cracking. The zone of thermal influence has four clearly distinguishable areas: the drop in microhardness; the stable values according to the Vickers method; the near-shock zone; the fusion zone. The microhardness of the weld surface of the cushion is 410 Vickers or 42 Rockwell, which creates conditions for increasing the wear resistance of the surface friction. The use of electrodes with a low-carbon rod is advisable when conducting surfacing reinforcement of heat-strengthened steels.

Long uninterrupted photometric observations of the Wolf-Rayet star EZ CMa by the Toronto BRITE satellite reveal a very fast apsidal motion

Context. The variability of the Wolf-Rayet star EZ CMa has been documented for close to half a century, and a clear periodicity of ∼3.7 days is established. However, all attempts to prove that it is a binary have failed because the photometric, spectroscopic, and polarimetric variations are not coherent over more than a few orbital cycles. Aims. In this Letter we show that the lack of coherence in the variability can be explained with a very rapid apsidal motion in a binary orbit. Methods. We measured the times of minima in a recently published exceptionally long photometric light curve obtained by the Toronto BRITE satellite. The apsidal motion and the system eccentricity are determined from the length of the time intervals between these minima, which alternate in their duration, following a pattern that is clearly associated with apsidal motion. These minima are superposed on brightness enhancements of the emission from a shock zone, which occur at about the times of periastron phases. Results. We determine the orbital periodicity, Pa = 3.63 d, and the period of the apsidal motion, U ≃ 100 d, which together yield an average sidereal period of Ps = 3.77 d. The eccentricity is found to be close to 0.1. The rate of periapsis retreat changes significantly over the period of observation and is determined to be −16° P−1a at the beginning of the observing period and −10° P−1a at the end. Conclusions. We demonstrate that by introducing a fast apsidal motion, the basic photometric variability is very well explained. The binary nature of EZ CMa is now established. This might imply that other apparently single Wolf-Rayet stars that emit hard X-rays, similar to EZ CMa, are also binaries.

Control of recollection by slow gamma dominating mid-frequency gamma in hippocampus CA1

ABSTRACTBehavior is used to assess memory and cognitive deficits in animals like Fmrl-null mice that model Fragile X Syndrome, but behavior is a proxy for unknown neural events that define cognitive variables like recollection. We identified an electrophysiological signature of recollection in mouse dorsal CA1 hippocampus. During a shocked-place avoidance task, slow gamma (SG: 30-50 Hz) dominates mid-frequency gamma (MG: 70-90 Hz) oscillations 2-3 seconds before successful avoidance, but not failures. Wild-type but not Fmrl-null mice rapidly adapt to relocating the shock; concurrently, SG/MG maxima (SGdominance) decrease in wild-type but not in cognitively inflexible Fmrl-null mice. During SGdominance, putative pyramidal cell ensembles represent distant locations; during place avoidance, these are avoided places. During shock relocation, wild-type ensembles represent distant locations near the currently-correct shock zone but Fmrl-null ensembles represent the formerly-correct zone. These findings indicate that recollection occurs when CA1 slow gamma dominates mid-frequency gamma, and that accurate recollection of inappropriate memories explains Fmrl-null cognitive inflexibility.

Turbulent jet in crossflow analysis with LES approach

Purpose This study aims to investigate effects of sonic jet injection into supersonic cross-flow (JISC) numerically in different dynamic pressure ratio values and free stream Mach numbers. Design/methodology/approach Large Eddy simulation (LES) with dynamic Smagorinsky model is used as the turbulence approach. The numerical results are compared with the experimental data, and the comparison shows acceptable validation. Findings According to the results, the dynamic pressure ratio has critical effects on the zone related to barrel shock. Despite free stream Mach number, increasing dynamic pressure ratio leads to expansion of barrel shock zone. Consequently, expanded barrel shock zone would bring about more obstruction effect. In addition, the height of counter-rotating vortex pair increases, and the high-pressure area before jet and low-pressure area after jet will rise. The results show that the position of barrel shock is deviated by increasing free stream Mach number, and the Bow shock zone becomes stronger and close to barrel shock. Moreover, high pressure zone, which is located before the jet, decreases by high free stream Mach number. Practical implications In this study, LES with a dynamic Smagorinsky model is used as the turbulence approach. Effects of sonic JISC are investigated numerically in different dynamic pressure ratio values and free stream Mach numbers. Originality/value As summary, the following are the contribution of this paper in the field of JISC subjects: several case studies of jet condition have been performed. In all the cases, the flow at the nozzle exit is sonic, and the free stream static pressure is constant. To generate proper grid, a cut cell method is used for domain modelling. Boundary condition effect on the wall pressure distribution around the jet and velocity profiles, especially S shape profiles, is investigated. The results show that the relation between representing the location of Mach disk centre and at transonic regime is a function of second-order polynomial, whereas at supersonic regime, the relationship is modelled as a first-order polynomial. In addition, the numerical results are compared with the experimental data demonstrating acceptable validation.