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In the present investigation, AA6351 aluminum alloy matrix composites reinforced with various percentages of AlN particles were fabricated by stir casting technique. The percentage of AlN was varied from 0 to 20% in a step of 4%. The prepared AA6351-AlN composites were characterized using scanning electron microscope (SEM) and x-ray diffraction (XRD). The mechanical properties such as micro-hardness, compression strength, flexural strength, and tensile strength of the proposed composite have been studied. X-ray diffraction patterns confirm the presence of AlN particles in the composites. SEM analysis reveals the homogeneous distribution of AlN particles in the AA6351 matrix. The mechanical properties of the composite were found to be noticeably higher than that of the plain matrix alloy due to augmented particle content. The produced composites exhibit superior mechanical properties when compared with unreinforced matrix alloy. Fracture surface analysis of tensile specimens show the ductile–brittle nature of failure in the composites.

The El Niño–Southern Oscillation (ENSO) influence on tropical cyclone (TC) activity (frequency, genesis location, and intensity) in the Bay of Bengal (BoB) during the primary TC peak season (October–December) are studied for the period of 1993–2010. The study shows that during primary TC peak season, accumulated cyclone energy in the BoB is negatively correlated with Niño3.4 sea surface temperature anomaly. Under La Niña regime number of extreme TC cases (wind speed >64 kt) increases significantly in the BoB during the primary TC peak season. The analysis further shows that negative Indian Ocean dipole year is also favorable for extreme TC activity in the BoB during the primary TC peak season. The existence of low‐level cyclonic (anticyclonic) vorticity, enhanced (suppressed) convection, and high (low) tropical cyclonic heat potential (TCHP) in the BoB provides favorable (unfavorable) conditions for the TC activity under La Niña (El Niño) regimes together with weak vertical wind shear and high sea surface temperature (SST). The genesis location of TC shifts to the east (west) of 87°E in the BoB during La Niña (El Niño) regime due to the variability in convective activity. The probable reason for the intense TC during a La Niña regime is likely explained in terms of longer track for TCs over warm SST and high TCHP due to eastward shifting of genesis location together with other favorable conditions. The variability of Madden‐Julian Oscillation and its influence on TC activity in the BoB during La Niña and El Niño regime are also examined. Key Points Role of ENSO on the modulation of Bay of Bengal cyclones Large‐scale ocean and atmospheric processes during BoB cyclones Combined effect of ENSO and the MJO on BoB cyclones

In this article, role of ocean advection and atmospheric heat fluxes on recent decadal (2000–2019) decrease of sea-ice in the Arctic (60∘ N–90∘ N) has been investigated using an ocean sea-ice coupled model, known as Modular Ocean Model of version 5 with Sea Ice Simulator (MOMSIS). MOMSIS successfully simulates AVHRR observed decadal change of sea-ice concentration (SIC) and sea surface temperature (SST) in the Arctic during all four seasons; winter (December–February), spring (March–May), summer (June–August) and autumn (September–November) except few occasions. Also, best performance of the MOMSIS are restricted at south of 80∘ N with statistical significance of more than 90%. We have also divided Arctic Ocean into eight sectors for our detailed analysis. Maximum decadal decrease of SIC and increase of SST has been observed in the Barents (sector 2), Kara (sector 3) and Laptev (sector 4) Sea regions of the Arctic using both AVHRR and MOMSIS with statistical significance of 90%. Also, very small decadal decrease (increase) of SIC (SST) has been observed in the Norwegian (sector 1) and Beaufort (sector 7) Sea regions of the Arctic using both AVHRR and MOMSIS. Mixed layer heat budget has been performed to understand role of thermodynamics processes on decadal change of SIC and SST in the Arctic. Strong decadal change of net atmospheric heat (NAH) fluxes are responsible for high decadal change of SIC and SST in the Barents (sector 2), Kara (sector 3) and Laptev (sector 4) Sea regions of the Arctic. In the Norwegian (sector 1) and Beaufort (sector 7) Sea, strong destructive interference between decadal change of NAH fluxes and ocean advection play an important role for small decadal change of SIC and SST during all four seasons. Also, for ocean advection, horizontal part dominate compared to vertical in all eight sector of the Arctic.

The prediction of sea surface temperature (SST) in real-time or online mode has applications in planning marine operations and forecasting climate. This paper demonstrates how SST measurements can be combined with numerical estimations with the help of neural networks and how reliable site-specific forecasts can be made accordingly. Additionally, this work demonstrates the skill of a special wavelet neural network in this task. The study was conducted at six different locations in the Indian Ocean and over three time scales (daily, weekly, and monthly). At every time step, the difference between the numerical estimation and the SST measurement was evaluated, an error time series was formed, and errors over future time steps were forecasted. The time series forecasting was affected through neural networks. The predicted errors were added to the numerical estimation, and SST predictions were made over five time steps in the future. The performance of this procedure was assessed through various error statistics, which showed a highly satisfactory functioning of this scheme. The wavelet neural network based on the particular basic or mother wavelet called the “Meyer wavelet with discrete approximation” worked more satisfactorily than other wavelets.

The Indian Ocean Observing System (IndOOS), established in 2006, is a multinational network of sustained oceanic measurements that underpin understanding and forecasting of weather and climate for the Indian Ocean region and beyond. Almost one-third of humanity lives around the Indian Ocean, many in countries dependent on fisheries and rain-fed agriculture that are vulnerable to climate variability and extremes. The Indian Ocean alone has absorbed a quarter of the global oceanic heat uptake over the last two decades and the fate of this heat and its impact on future change is unknown. Climate models project accelerating sea level rise, more frequent extremes in monsoon rainfall, and decreasing oceanic productivity. In view of these new scientific challenges, a 3-yr international review of the IndOOS by more than 60 scientific experts now highlights the need for an enhanced observing network that can better meet societal challenges, and provide more reliable forecasts. Here we present core findings from this review, including the need for 1) chemical, biological, and ecosystem measurements alongside physical parameters; 2) expansion into the western tropics to improve understanding of the monsoon circulation; 3) better-resolved upper ocean processes to improve understanding of air–sea coupling and yield better subseasonal to seasonal predictions; and 4) expansion into key coastal regions and the deep ocean to better constrain the basinwide energy budget. These goals will require new agreements and partnerships with and among Indian Ocean rim countries, creating opportunities for them to enhance their monitoring and forecasting capacity as part of IndOOS-2.

This study investigates sea surface temperature (SST) and precipitation variations in the eastern Arabian Sea (EAS) induced by the northward-propagating Indian summer monsoon (ISM) intraseasonal oscillations (MISOs) through analyzing satellite observations and the Climate Forecast System Reanalysis (CFSR) and performing ocean general circulation model (OGCM) experiments. MISOs in the EAS achieve the largest intensity in the developing stage (May–June) of the ISM. The MISOs induce intraseasonal SST variability primarily through surface heat flux forcing, contributed by both shortwave radiation and turbulent heat flux, and secondarily through mixed layer entrainment. The shallow mixed layer depth (MLD < 40 m) in the developing stage and decaying stage (September–October) of the ISM significantly amplifies the heat flux forcing effect on SST and causes large intraseasonal SST variability. Meanwhile, the high SST (>29°C) in the developing stage leads to enhanced response of MISO convection to SST anomaly. It means that the ocean state of the EAS region during the developing stage favors active two-way air–sea interaction and the formation of the strong first-pulse MISO event. These results provide compelling evidence for the vital role played by the ocean in the MISO mechanisms and have implications for understanding and forecasting the ISM onset. Compared to satellite observation, MISOs in CFSR data have weaker SST variability by ∼50% and biased SST–precipitation relation. Reducing these biases in CFSR, which provides initial conditions of the National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2), may help improve the ISM rainfall forecast.

We explore the decadal variability of teleconnection from tropical Pacific to the Indian summer monsoon rainfall (ISMR) using various observational and Reanalysis datasets for the period 1958–2008. In confirmation with the earlier findings, we find that the interannual correlations between the various SST indices of ENSO and ISMR have continued to weaken. Interestingly, we find that even the robust lead correlations of the tropical pacific warm-water-volume with ISMR have weakened since late 1970s. Our analysis suggests that there is a relative intensification of the cross-equatorial flow from the southern hemisphere into the equatorial Indian Ocean associated with ISMR due to strenghtening of Mascarene High. Further, a shift in the surface wind circulation associated with monsoon over the northern pacific since late 1970s has resulted in a strenghtened cyclonic seasonal circulation south-east of Japan. These changed circulation features are a shift from the known circulation-signatures that efficiently teleconnect El Niño forcing to South Asia. These recent changes effectively weakened the teleconnection of the El Niño to ISMR.

In the recent days, the employ of aluminum alloy has enriched dramatically especially in engineering applications extensively employed in ship building, aerospace, structural, non-structural and automotive applications like driveshaft, wheels, crankshaft, connecting rod, chassis, brake rotors, cylinder blocks and piston etc. The foremost objective of this evaluation is to optimize the impacts of stir casting parameters of Aluminium Alloy AA7178/Si 3 N 4 with response of tensile strength by utilizing Taguchi approach. MINITAB software was employed for conducting the Taguchi analysis. The stir casting parameters of this examination are stirring speed, stirring time and reinforcement percentage. The tensile behaviour of AA7178/Si 3 N 4 composites for varying filler mass proportionate, stirring speed and stirring time were assessed employing a “universal testing machine”, and using a L 9 (3) 3 Taguchi orthogonal array. The nine samples of trials are employed to estimate the tensile behaviour of the composite material. The Analysis of Variance (ANOVA) is extensively assistance to intimate which parameter is highly impact for this evaluation. Amid those factors, filler content as highly influenced factor to response value followed as stirring time and stirring rpm.

In this work, AA7178-10 wt.% ZrB 2 Metal Matrix Composite was produced using stir casting route and the mechanical properties of the composites were studied. The microstructure and elemental verification were done by using Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). Among the various non-traditional machining processes, Wire Electrical Discharge Machining (WEDM) is an important process for machining MMCs. The objective of this work is to investigate the effect of Peak current (I), Pulse On-Time (PT On ), Pulse Off Time (PT Off ) and Wire feed rate (WF) on the combined objective of maximum Metal Removal Rate (MRR) and minimum Surface Roughness (SR) during machining of AA7178-10 wt.% ZrB 2 composite using Taguchi based Grey Relational Analysis (GRA). L 16 orthogonal array, for the four machining parameters at four levels each, was opted to conduct the experiments. Analysis of variance (ANOVA) was performed to find the validity of the experimental plan followed in the present work. Results show that, maximum MRR and minimum SR can be achieved for the peak current (11 A), Pulse On-Time (112 μs), Pulse Off Time (45 μs) and Wire feed rate (7 m/min).

As a technique of producing fabric engineering scaffolds, three-dimensional (3D) printing has tremendous possibilities. 3D printing applications are restricted to a wide range of biomaterials in the field of regenerative medicine and tissue engineering. Due to their biocompatibility, bioactiveness, and biodegradability, biopolymers such as collagen, alginate, silk fibroin, chitosan, alginate, cellulose, and starch are used in a variety of fields, including the food, biomedical, regeneration, agriculture, packaging, and pharmaceutical industries. The benefits of producing 3D-printed scaffolds are many, including the capacity to produce complicated geometries, porosity, and multicell coculture and to take growth factors into account. In particular, the additional production of biopolymers offers new options to produce 3D structures and materials with specialised patterns and properties. In the realm of tissue engineering and regenerative medicine (TERM), important progress has been accomplished; now, several state-of-the-art techniques are used to produce porous scaffolds for organ or tissue regeneration to be suited for tissue technology. Natural biopolymeric materials are often better suited for designing and manufacturing healing equipment than temporary implants and tissue regeneration materials owing to its appropriate properties and biocompatibility. The review focuses on the additive manufacturing of biopolymers with significant changes, advancements, trends, and developments in regenerative medicine and tissue engineering with potential applications.