Search

Abstract We use a 16-month-long, 20 Hz wind data from a mooring deployed in the Bay of Bengal (BoB) to study the characteristics of turbulent wind stress ( $${u}{\prime}{w}{\prime})$$ u ′ w ′ ) events in the marine atmospheric boundary layer (MABL). Quadrant analysis of the motion-corrected $${u}{\prime}$$ u ′ and $${w}{\prime}$$ w ′ suggests that sweep and ejections, representing downward stress transfer into the ocean, dominate the $${u}{\prime}{w}{\prime}$$ u ′ w ′ (~ 140%). In comparison, outward and inward interactions representing an upward stress transfer into the atmosphere provide the counter-contribution (~ 40%). We found a wind speed (ws) dependency on stress transfer for ws > 3 m/s, while for low ws, the swell-dominated ocean state modulates the $${u}{\prime}{w}{\prime}$$ u ′ w ′ with a significant reverse stress transfer into the atmosphere, especially during intermonsoon periods. It is found that for weak winds ( $$ws$$ ws

This study presents the synthesis and in-depth evaluation of a novel Tin(IV) oxide/reduced graphene oxide (SnO2/rGO) nanocomposite developed as an electrode material for advanced electrochemical supercapacitors. Utilizing a scalable synthesis method with optimized parameters, the resulting nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), revealing its well-defined morphology, crystal structure, and composition. Comprehensive electrochemical assessments, including galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), demonstrated that SnO2/rGO exhibits superior performance metrics compared to pure SnO2. Notably, at a current density of 1 A g−1, the SnO2/rGO nanocomposite achieved a specific capacitance of 140 F g−1, surpassing the 133 F g−1 of pure SnO2. These findings highlight the SnO2/rGO nanocomposite's potential to significantly enhance energy storage capabilities, making it a promising candidate for applications in electric vehicles, portable electronics, and sustainable energy systems.

Waspaloy, a nickel-based super alloy, has much potential in gas turbine component production. Machining this type of material using the traditional manufacturing method is very hard. Hence, electrical discharge machining (EDM) was selected for the investigation of the machining characteristics of Waspaloy by choosing the control parameters, namely, current, voltage, pulse on time, pulse off time, and spark gap. Gray relational analysis is carried out using 18 experiments according to an orthogonal array (L18) to determine the gray relation grade for this machining process with multiple machining characteristics such as material removal rate (MR), tool wear rate (TW), and surface roughness (SR). The significant objective of the multi objective optimization to attain high MR, low TW, and low SR is found out. From gray relation optimization, the optimum machining conditions for EDM, namely, current: 26 A, voltage: 200 V, pulse on time: 120 μs, pulse on time: 10 μs, and spark gap: 0.15 m, have been identified. The foremost parameter affecting the responses was found to be peak current.

Abstract The present study examines the drivers of the observed increasing trend in the Genesis Potential Index (GPI) of the post-monsoon season (October-November-December) tropical cyclones in the Arabian Sea (AS) during the period, 1998–2021. The increase in atmospheric moisture loading, ocean heat content in the upper 300 m (OHC300) and reduction in vertical wind shear are the major factors which caused the intensification in cyclone GPI in the recent decades. The increase in atmospheric moisture loading and OHC300 are consistent with the overall observed ocean warming trend of the region. However, the reduction in vertical wind shear has resulted from an anomalous large-scale upper atmospheric anticyclonic circulation over central India. Further investigation shows a concurrent transition of the Warm Arctic Cold Eurasia (WACE) pattern to its positive phase which strengthened and shifted the Subtropical Jet (STJ) poleward. This resulted in the anticyclonic circulation anomaly and altered the upper tropospheric zonal winds over the AS cyclone genesis region, weakening the vertical wind shear. The study demonstrates a possible physical mechanism through which remote forcing due to changes in the northern high-latitude climate can influence the AS cyclone genesis.

This case study has made an effort to show the impact of improved ocean initial conditions (ICs) in a coupled forecast system (CFSv2) simulation on the seasonal prediction of Indian summer monsoon rainfall (ISMR). CFSv2 is used as an operational dynamical model for the seasonal prediction of ISMR. Here, we show an improved ISMR skill by initializing the ocean component of CFSv2 using new improved ocean ICs based on Global Ocean Data Assimilation System (GODAS) analysis. This new analysis is better than the NCEP GODAS, which uses the earlier-generation ocean model MOM4p0d and assimilates observed temperature and synthetic salinity using the 3DVar assimilation scheme. However, the new, improved GODAS analysis uses the MOM4p1 ocean model and assimilates observed salinity instead of synthetic salinity. We performed twin sets of nearly identical model experiments differing only in their ICs, with one set using NCEP ICs and the other using the new ICs (NIC). The NIC experiment consistently shows better El Niño–Southern Oscillation prediction skill than the NCEP IC experiment. This advancement leads to improvement in the ISMR skill. We found that the substantial improvements in both oceanic and atmospheric variables in a coupled feedback system contributed to the improved ISMR skills. The enhanced ISMR skill score of the NIC experiment might be the result of improved teleconnections, better depiction of large-scale monsoon circulations, and reduced model drift.

Abstract The role of ocean variability is at a focal point in improving the weather and climate forecasts at different spatial and temporal scales. We study the effect of antecedent southwestern Indian Ocean mean sea level anomaly (MSLA) and sea surface temperature anomalies (SSTA) as a proxy to upper ocean heat capacitance on all India summer monsoon rainfall (AISMR) during 1993–2019. SSTA and MSLA over the southwestern Indian Ocean (SWIO) have been influenced by El Niño-Southern Oscillation (ENSO), the impact of ENSO-induced SWIO variability was low on rainfall variability over several homogeneous regions. Rainfall over northeast (NE) and North India (EI) has been modulated by ENSO-induced SSTA and MSLA over SWIO, thus effecting the total AISMR magnitude. The ENSO-induced changes in heat capacitance (SSTA and MSLA) over SWIO during antecedent months has less impact on west coast of India, central India and North India (NI) rainfall variability. The long-term trend in pre-monsoonal SSTA and MSLA over SWIO shows decreasing rainfall trend over NI, NE, and EI in the recent time. Furthermore, the cooler (warmer) anomaly over the western Indian Ocean affects rainfall variability adversely (favourably) due to the reversal of the wind pattern during the pre-monsoon period. While SSTA and MSLA are increasing in the SWIO, large-scale variability of these parameters during preceding winter and pre-monsoon months combined with surface winds could impact the inter-annual AISMR variability over homogeneous regions of India. Similarly, from an oceanic perspective, the antecedent heat capacitance over SWIO on an inter-annual time scale has been the key to the extreme monsoon rainfall variability.

In order to reduce carbon emissions, a growing reliance on renewable energy sources such as solar energy is required. As a result of their ability to store excess solar electricity that may be used at a later time to reduce waste and increase utility profits, battery energy storage systems (BESSs) have emerged as a factor for power systems that integrates solar power system. BESSs are traditionally put on buses in solar farms, allowing extra electricity via solar to be stored instantaneously and transmission line losses to be kept to an absolute minimum. According to this placement strategy, BESS is exclusively built in the proximity of solar power plants. In this way, deployment of BESS without network topology consideration, and collaboration among BESSs is limited with capacity pooling to store excess electricity from photo voltaic (PV) panels. In this paper, we develop an optimal deployment of BESSs and it is associated with the estimation of the capacity using a multi-objective constraint modelling. The soft margin classifier minimize the curtailment associated with solar energy that considers both the power flow constraint and network topology. The results of entire model shows that the proposed soft margin classifier is efficient in storing the surplus power in the batter devices than other methods.

The development in current manufacturing technology entails better wear resistance materials. Inthis study, ZK60A Mg alloy matrix composites reinforced with x wt.% (x = 0, 4, 8 and 12 wt.%) of TiN powders are developed through powder metallurgy (PM) route. The tribological behaviour of the composites under dry sliding conditions was estimated using Pin-on-disc instrument. The influence of the control parameters such as wt.% of TiN, applied load , sliding velocity and sliding distance on the wear rate and co-efficient of friction were analysed using Taguchi coupled grey relational approach GRA and L16 orthogonal array is selected for performing design of experiments. The lowest WR of 0.01147 mm3/m and 0.2446 COF formed at 12 wt.% of ‘R’, 9.81 N of ‘P’, 5.24 m/s of ‘V’ and 1000 m of ‘D’. From Analysis of variance (ANOVA), the wt.% of TiN powder (P = 82.68%) was observed as a primary factor controlling the WR and COF of composites. Finally, confirmation trials were performed to validate the results. SEM examination ensures homogeneous disbursement of TiN powders in the matrix alloy. Addition of reinforcement results in increase in density and porosity. The higher hardness observed at 12wt.% TiN incorporated Mg alloy composite.

Powder Metallurgy (PM) was used to synthesize SiC (0, 5, 10, 15 & 20 wt%) and 1 wt% Yttria (Y2O3) reinforced aluminium (Al) metal matrix composites. The Al–SiC–Y2O3 hybrid composites samples were prepared for density (ρ), hardness (VHN), mechanical, tribological, and microstructural studies in accordance with ASTM standards. SEM images revealed an even spreading of SiC particles throughout the Al matrix and composition was verified by the characterization techniques. The addition of SiC and Y2O3 to their respective composites improved the VHN and ‘ρ’. The compressive strength (CS) of Al–SiC–Y2O3 composites increased while increasing the SiC. The higher compression strength (405 MPa) was obtained for the Al − 1 wt% Y2O3-20 wt% SiC- hybrid composites. The thermal conductivity (K) of Al–SiC–Y2O3 samples diminishes, as the hard SiC particles are gradually added. Furthermore, it was observed that accumulative the wt% of SiC in the aluminium metal matrix (AMMC) results in a novel material with a decreased wear rate. The better properties was achieved for the samples contain 20 wt% of SiC content in Al − 1 wt% Y2O3 matrix.

Abstract Sea ice extent (SIE) in the Weddell Sea attained exceptionally low levels in April (1.97 million km2) and May (3.06 million km2) 2019, with the values being ~22% below the long-term mean. Using in-situ, satellite and atmospheric reanalysis data, we show the large negative SIE anomalies were driven by the passage of a series of intense and explosive polar cyclones (with record low pressure), also known as atmospheric ‘bombs’, which had atmospheric rivers on their eastern flanks. These storms led to the poleward propagation of record-high swell and wind waves (~9.6 m), resulting in southward ice advection (~50 km). Thermodynamic processes also played a part, including record anomalous atmospheric heat (>138 W m−2) and moisture (>300 kg m−1s−1) fluxes from midlatitudes, along with ocean mixed-layer warming (>2 °C). The atmospheric circulation anomalies were associated with an amplified wave number three pattern leading to enhanced meridional flow between midlatitudes and the Antarctic.

We studied the electrochemical corrosion of AA6063 aluminium composite fabricated using the stir casting technique and processed using Equal-Channel Angular Pressing (ECAP). Potentiodynamic polarisation and Electrochemical Impedance Spectroscopy were used to assess the corrosion resistance of a metal and ceramic mixture reinforced aluminium composite under various processing conditions. The corrosion resistance of the fabricated composite increased with addition of the metallic reinforcement. The AA6063/(12%)Si3N4/(6%)Cu(NO3)2 composite exhibited a 63% lower corrosion rate. Increased dislocation density, grain processing, participate re-distribution, alteration of the cathodic site surface, and an increase in the number of grain boundaries changed the corrosion behaviour after ECAPA. Elongated grains and grain boundaries are more susceptible to combative solutions, resulting in corrosion at these locations owing to lower corrosion resistance than cast specimens. However, after ECAP, the specimen exhibits a shallow and uniformly corroded surface. Subsequently, a Pin-on-Disc tribometer was used for the dry sliding tribological characterisation of the nitride and nitrate particle reinforced AA6063/Si3N4/Cu(NO3)2 hybrid metal matrix composite according to the ASTM G99-05 standards using L27 orthogonal array. The ECAPA with the process parameters of 10 N applied load, 1000 m sliding distance, and 400 rpm sliding speed yielded 73% higher wear resistance for the above composite compared to the cast composite, along with a 40.7% reduction in the coefficient of friction.

In this work, Silicon Carbide (SiC) reinforced Mg/3Al matrix composite was developed via powder metallurgy (PM) method. Friction coefficient (COF) and wear rate (WR) of the composite was studied using Pin on disc wear tester. Scanning Electron Microscope (SEM) was used to investigate the microstructure of sintered samples. During the experiments, L16 orthogonal design was followed. Wear analysis was done with four wear control factors such as the reinforcement (Wt.%), the applied load (‘P’), the sliding velocity (‘V’) and the sliding distance (‘D’). In this study, the optimal combination of parameters was found using signal-to-noise (S/N) ratio analysis. Based on the analysis of variance (ANOVA), the ‘P’ and Wt.% of SiC are the two parameters that have the greatest influence on WR and COF. From the analysis, Mg/3Al/9SiCcomposites exhibited better wear properties among other composition tested. Worn surface analysis was conducted for the tested samples and the SEM images are reported.

Nowadays, scarcity arises in almost all our basic needs, including water, fuel, and food. Recycling used and scrapped things for a valuable commodity is highly appreciable for compensating for the globally fast-growing demand. This paper aims to investigate waste tyre oil for preparing biodiesel for CI engines by enhancing their performance with hybrid nanoparticles for preparing nanofuel and hybrid nanofuel. The nanoparticles (30–40 nm) of MWCNT and TiO2 were utilized to prepare nanofuels with nanoparticle concentrations of MWCNT (300 ppm) and TiO2 (300 ppm), respectively. In the case of hybrid nanofuel, the nanoparticle concentration of MWCNT (150 ppm) and TiO2 (150 ppm) was preferred. The performance of the proposed nanofuel and hybrid nanofuel with pure diesel was evaluated. The proposed fuel performance outperforms the combustion performance, has higher engine efficiency, and has fewer emissions. The best performances were noticed in hybrid nanofuel that has 32% higher brake thermal efficiency than diesel and 24% and 4% lower BSFC and peak pressure than diesel, respectively. The emission performance is also 29%, 50%, and 13% lower in CO, HC, and CO2 emissions than that in pure diesel.

This work, examines the Surface Roughness (SR) of composite consisting Aluminium alloy (AA6061), Magnesium and Rock dust during turning process. To study the performance, three different test specimens with different constituents of Al 6061-T6, AZ31 and Rock dust were prepared by stir casting method. Turning experiments were carried out using MTAB Siemens – CNC lathe. The input parameters for machining are speed, depth of cut & feed and output response is surface roughness For each test specimen, there are 15 turning operations were performed using Box-Ben hen Design approach. To analyze the process parameters for SR, the models of ANOVA and Decision Tree (DT) algorithms were performed. Both algorithms are confirmed that, speed is the most significant factor for SR. The addition of AZ 31 with 1% and rock dust of 2% in AA6061 produced better surface finish. Regression models of linear regression, multilayer perception and support vector regression from data science were formulated to find the relationship between variables. Among these models multi layer perception produced minimum root mean square error.

Various regional climatic factors influence glacier mass balance and thus control the water budget of the Himalayan rivers. However, the scarcity of observational data hinders a detailed understanding of the processes governing glacier mass balances in the Himalaya. Here we analyze the mass balance of the Sutri Dhaka Glacier, a debris-free glacier in the Chandra basin (western Himalaya) combining field observations and a physically based model to understand the drivers of mass balance variability. The modeled energy flux showed that net shortwave radiation contributed 56% to the total surface energy fluxes, followed by net longwave radiation (27%), sensible heat (8%), latent heat (5%), and ground heat flux (4%). However, over the ablation zone, inward fluxes account for most of the total heat flux, resulting in strong summertime melting. The model estimated glacier mass balance was −1.09 ± 0.31 and −0.62 ± 0.19 m w.e. during 2015/16 and 2016/17, which matches well with the in situ glaciological mass balance of −1.16 ± 0.33 and −0.67 ± 0.33 m w.e., respectively. A sensitivity analysis demonstrates that the mass balance of the glacier is affected by both air temperature (−0.21 m w.e. a−1 °C−1) and precipitation (0.19 m w.e. a−1 (10%)−1) changes. Our study suggests that, the mass balance of the Sutri Dhaka Glacier is less sensitive to changes in the partitioning of precipitation into snow and rain because the majority of precipitation falls as snow during the winter when the temperature is well below 0°C.

The amount and spatial extent of Greenland Sea (GS) ice are primarily controlled by the sea ice export across the Fram Strait (FS) and by local seasonal sea ice formation, melting, and sea ice dynamics. In this study, using satellite passive microwave sea ice observations, atmospheric and a coupled ocean-sea ice reanalysis system, TOPAZ4, we show that both the atmospheric and oceanic circulation in the Nordic Seas (NS) act in tandem to explain the SIC variability in the south-western GS. Northerly wind anomalies associated with anomalously low sea level pressure (SLP) over the NS reduce the sea ice export in the south-western GS due to westward Ekman drift of sea ice. On the other hand, the positive wind stress curl strengthens the cyclonic Greenland Sea Gyre (GSG) circulation in the central GS. An intensified GSG circulation may result in stronger Ekman divergence of surface cold and fresh waters away from the south-western GS. Both of these processes can reduce the freshwater content and weaken the upper-ocean stratification in the south-western GS. At the same time, warm and saline Atlantic Water (AW) anomalies are recirculated from the FS region to the south-western GS by a stronger GSG circulation. Under weakly stratified conditions, enhanced vertical mixing of these subsurface AW anomalies can warm the surface waters and inhibit new sea ice formation, further reducing the SIC in the south-western GS.

In the current research study, AA6351 (Al-Si-Mg) is employed as matrix material and silicon nitride (Si3N4) particles as reinforcement material to manufacture the aluminum composites (AMCs). AA6351 matrix composites incorporated with several weight fractions of Si3N4 (0, 1, 2 and 3 wt.%) were synthesized via stir casting technique. The obtained composites were characterized through a scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS). EDS and XRD spectrums demonstrate the presence of Si3N4 reinforcement contents in the manufactured AMCs. The SEM analysis exhibits the even dissemination of Si3N4 particles in the Al alloy. The mechanical properties of the composites are examined by conducting several kinds of tests like compression test, impact test, tensile test and hardness test to understand the relationship between the weight percentages of reinforcement on the mechanical characteristics of the manufactured AMCs. The un-lubricant tribological characteristics of the proposed AMCs were assessed utilizing pin on disk tribometer. The hardness, compression and tensile strength of the AMCs were augmented concerning the mass proportion of reinforcement content. Finally, the wear test result reveals that the addition of nano-sized Si3N4 reinforcement contents up to a mass proportion of 3% downgrades the wear rate.

Abstract The Mascarene High (MH) is a semi-permanent subtropical high-pressure zone in the South Indian Ocean. Apart from its large influence on African and Australian weather patterns, it also helps in driving the inter-hemispheric circulation between the Indian Ocean in the south and subcontinental landmass in the north. Using observations and reanalysis products, this study for the first time investigates recent warming trend observed in the MH region during the Global Warming Hiatus (GWH) period (1998–2016). Significant positive trends are observed in sea surface temperature (SST), sea surface height (SSH) and oceanic heat content (OHC) during this period in the MH region. Mixed layer heat budget analysis reveals the dominant role of heat advection in the observed warming trend. During the GWH period, stronger zonal currents advect the warm waters from the Western Pacific (WP) towards the MH region via the Indonesian Throughflow (ITF). This warming in the MH reduces the sea level pressure therein and establishes a weak pressure gradient between the MH and the northern hemisphere landmass. This in-turn weakens the cross-equatorial winds in the western Indian Ocean.

In this work, low-carbon steel AISI-SAE grade 1010 with copper grade CDA 101 was joined by friction stir welding (FSW) using a tapered pin profiled tool. The rotational speed of the tool is 900 rpm, a traverse rate of 30 mm/min, and an axial force of 5 kN were used to produce the joints. The microstructural analysis and mechanical properties of the weld joints have been successfully examined. The optical microscopy, scanning electron microscopy, and X-ray diffraction (XRD) techniques were performed to examine the macropatterns and micropatterns of the welded joints. The tensile and hardness test was performed to evaluate the mechanical behaviours of the FSW joints. The fine ferrite grain features with uniform size were obtained in the microstructure of the nugget zone (stir zone). It is purely influenced by the alternating dynamic rearrangement (recrystallization) mechanism. High hardness was identified in the stir zone, even as the slightest stability was established in the heat-affected zone. The tensile investigation proposed that all the joints explored just lesser unbending nature than the parent material. The tensile strength of 181.5 MPa, the hardness of 144 VHN, and elongation of 14.03% were observed for the welded samples. The better properties for the weld joints were attained at 900 rpm spindle speed and tool traverse speed of 30 mm/min. The FSW is an attractive material joining process for both similar and dissimilar materials compared to other conventional types of joining processes, such as aerospace, marine engineering, shipbuilding, and industrial sector applications.

This paper reports the effect of snake grass (SG) fibers in Ficus exasperata Leaf Ash (FELA) concrete. Snake grass fibers of percentages 0.5, 1, 1.5, and 2 were used in this investigation. Tests of compressive strength, split tensile strength, and flexural strength and durability studies of salt resistance, sulphate resistance, and impact energy resistance were determined, and the test results are discussed in detail. Test results revealed that FELA ash of 15% replacement in cement showed remarkable binding property. Moreover, incorporation of snake grass fiber in concrete improves the strength, postcracking resistance, and energy absorption. It is also observed that 1.5% snake grass fiber incorporation in concrete exhibited better strength properties and energy absorption property than 0.5% and 1%. Also, beyond 1.5%, there is significant reduction in workability property. Regardless of durability property, the mix containing 1.5% snake grass fiber has shown better resistance against durability when compared with other mixes. It is also observed that penetration of chloride and sulphate ions made slight deterioration at sharp edges. Moreover, test results revealed that applications of FELA concrete with snake grass fiber can be effectively expanded in the construction industry.

In the current research, AA6082 aluminium alloy matrix composites (AAMCs) incorporated with various weight fractions of titanium diboride (0, 3, 6, and 9 wt%) were prepared via an in situ casting technique. The exothermic reaction between inorganic powders like dipotassium hexafluorotitanate (K2TiF6) and potassium tetrafluoroborate (KBF4) in molten Al metal contributes to the development of titanium diboride content. The manufactured AA6082-TiB2 AAMCs were evaluated using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The mechanical properties and wear rate (WR) of the AAMCs were investigated. XRD guarantees the creation of TiB2 phases and proves the nonappearance of reaction products in the AMCs. SEM studies depict the even dispersion of TiB2 in the matrix alloy. The mechanical and tribological properties (MTP) of the AAMCs showed improvement by the dispersion of TiB2 particles. The WR decreases steadily with TiB2 and the least WR is seen at nine weight concentrations of TiB2/AA6082 AAMCs. Fabricated composites revealed 47.9% higher flexural strength and 14.2% superior compression strength than the base AA6082 alloy.

Clean technology-based natural fiber composite fabrication is the prime aim of this piece of research. Natural fibers highly replace metal usage in industries and automobile, marine, medical applications, and so on. Vast amounts of natural fibers are freely available in all areas. In this research, work nanofiller material such as nano form waste coir fiber is collected from used car seat. The 10 wt.% of nanofiller material is added to the preparation of natural nanocomposites (ramie and abaca fiber). Hybrid composites are fabricated with the influence of different process parameters, namely, fiber weight percentage (20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.%), NaOH action % (4%, 6%, 8%, and 10%), compression pressure (9 MPa, 12 MPa, 15 MPa, and 18 MPa), and temperature (100°C, 120°C, 140°C, and 160°C). Furthermore, the strength of this hybrid composite has analyzed by conducting flexural, impact, and shore hardness tests. These tests have provided the influence of selected parameters and their effects on the results of experimental work. In the flexural analysis, 6% of NaOH action has offered maximum flexural strength of the specimens. Correspondingly in the impact test, 30 wt.% of fiber is produced higher impact strength. Finally, applying 15 Mpa of compression pressure records the maximum shore hardness.

This research put forth an effort to produce AA5083 (Al-4.4 Mg-0.7 Mn-0.15 Cr)-12 wt.% MoO3 composite via the stir casting (SC) process, and the effects of process parameters such as pulse on time (TON), pulse off time (TOFF), and current (I) on the wire electrical discharge machining (WEDM) characteristics such as metal removal rate (MRR) and surface roughness (SR) were investigated using the Taguchi method. Numerous unconventional machining methods are accessible to machine MMCs; among that, WEDM is a significant method. ANOVA was utilized to identify the suitable parameters to obtain maximum MRR and least SR. From the analysis, it is clear that TON 120 (μs), TOFF 50 (μs), and I 3 (A) are the noteworthy parameters to acquire maximum MRR and TON 100 (μs), TOFF 40 (μs), and I 3 (A) are the noteworthy parameters to acquire least SR. ANOVA results for MRR showed that TOFF is the extreme inducing factor with the percentage contribution of 27.92% tracked by TON and I with the percentage contribution of 12.09% and 5.07%, respectively. ANOVA results for SR showed that TOFF is the extreme inducing factor with the percentage contribution of 60.33% tracked by TOFF and I with the percentage contribution of 12.31% and 0.33%, respectively.

In this work, copper (Cu) matrix composite reinforced with titanium carbide (TiC) was fabricated by powder metallurgy (PM) method with the varying TiC content from 0% to 12% by weight in the step of 4%. The required weight percentage of powders was milled in an indigenously developed ball milling setup. Green compacts were made using a computer-controlled hydraulic press (400 kN) and sintered in a muffle furnace at a temperature of 950°C. Scanning electron microscope (SEM) was used to analyze the distribution of TiC particles in Cu matrix in as-sintered conditions. X-ray diffraction (XRD) analysis resulted in the existence of respective phases in the produced composites. The structural characteristics such as stress, strain, dislocation density, and grain size of the milled composites were evaluated. Cold upsetting was conducted for the sintered composites at room temperature to evaluate the axial (σz), hoop (σө), hydrostatic (σm), and effective (σeff) true stresses. These stresses were analyzed against true axial strain (εz). Results showed that the increase in the inclusion of weight percentage of TiC into the Cu matrix increases density, hardness, (σz), (σө), (σm), (σeff), and stress ratio parameters such as (σz/σeff), (σθ/σeff), (σm/σeff), and (σz/σθ) of the composites.

The aim of the present work is to develop novel hybrid composites using areca, kenaf, and snake grass fibers as reinforcement and epoxy as the matrix. The areca, kenaf, and snake grass fibers were extracted from Catechu Linnaeus, Hibiscus cannabinus, and Sansevieria Ehrenbergii plants, respectively, and treated with 5% NaOH to improve the interfacial adhesion between the hydrophilic fiber and the hydrophobic matrix. Hybrid composites were developed by the compression molding technique and formulated based on the weight fraction of fibers. Tensile, flexural, and impact strength and hardness samples were prepared as per ASTM D 3039, ASTM D 790, ASTM D 256, and ASTM D 2240, respectively. The effects of alkaline treatment on developed hybrid composites were investigated. The developed hybrid composites with 20% wt. snake grass and 10% wt. areca fiber present interesting mechanical properties with a tensile strength of 58 MPa, flexural strength of 124 MPa, impact strength of 5.24 kJ/m2, and hardness of 88. The results indicate that maximum mechanical properties were obtained for alkaline-treated fiber composites with 20% wt. snake grass fiber compared to untreated fiber composites owing to better adhesion between the treated fiber and the matrix. The effect of alkaline treatment was analyzed by Fourier transform infrared. The fractured surfaces of tested samples were analyzed by scanning electron microscopy.

This study intends to optimize the end milling process variables for additively manufactured (AM) Inconel 718 alloy through the direct metal laser sintered (DMLS) method. Surface roughness and material removal rate have been considered as output responses. The end milling experiments were conducted using the design of experiments with an L9 orthogonal array (OA) by varying the process variables like feed rate (mm/min), cutting speed (m/min), and depth of cut (mm). Taguchi technique was used to optimize the process variables. Examination of the variance table is working to regulate each variable’s percentage contribution and significance in end milling experiments. The chip morphology of the DMLS Inconel 718 plate reveals that, at lower cutting speed, irregular and discontinuous chips were formed.

Natural fibers are an increasing potential alternative to synthetic fibers in recent research, due to their unique properties and weight ratio in composite materials. In this work, the banyan mat and ramie mat are used as reinforcement phase and the epoxy polymer is used as matrix material, and granite nanoparticles are used as filler for making composite laminates. The two phases of reinforcing and matrix were taken at an equal ratio of 50% in each, and the conventional hand layup process was fabricated making five different sequences of laminates. In this analysis, the dynamical mechanical properties of this hybrid composite are identified with the erratic weight ratio of banyan mat and ramie mat fabrics. The results revealed the maximum storage modulus is 1580 MPa at 93.8°C and a loss modulus of 298 MPa at 93.8°C in sample A, 12% more storage modulus, 17% more loss modulus was obtained in sample A compared to sample B, and 29% E′ and 27% E″ more compared to sample E and also using storage modulus, loss modulus, damping factor are the viscoelastic behavior which can reveal the glass transition temperature of hybrid composite laminates by conducting dynamic mechanical analysis, and SEM test was used to identify the failure mode of hybrid composite.

Steam generation and utilization are needed in many industries and home appliances with, specific requirements. Though there are numerous categories of boilers available for steam generation, this analysis concentrated on the water tube boiler since it produces more steam and offers better safety measures. Taguchi techniques are considered in this entire research work completed through design of experiments (DOE). Orthogonal array L16 is selected to examine the steam generation with four process parameters and four levels. Selected process parameters are namely temperature of feed water (°C), the pressure of feed water (bar), cold water supply (liters), and boiler drum pressure (bar). The response of this study is the as steam generation to since increasing the steam is a target of this investigation. The experimental value of the steam generation is compared with the desired range; most of the response values are within the predicted value. Further, the superheated steam temperature and pressure analysis were also carried out. The maximum steam generation is achieved as 84.31 L; registered in the 15th run of the experiment.

Aerospace alloys with reduced wall thickness but possessing higher hardness, good tensile strength and reasonable corrosion resistance are essential in manufacturing of structures such as fuselage. In this work, friction stir welding has been carried out on such an aerospace aluminum alloy AA8090 T87 which contains 2.3% lithium. Tool rotational speed of 900 rpm and traverse speeds of 90 mm/min., 110 mm/min. are the welding parameters. Hardness analysis, surface roughness analysis and corrosion analysis are conducted to analyze the suitability of the joint for the intended application. The samples were corrosion tested in acid alkali solution and they resulted in the formation of pits of varying levels which indicate the extent of surface degradation. Hardness of the samples was measured after corrosion analysis to observe the changes. The analysis suggests that the change in tool traverse speed transformed the corrosion behavior of the joint and affected both the hardness and surface roughness which mitigated the quality of the joint.

The integration of flow-induced mechanical interlocking, interlayer-controlled atomic diffusion and self-reacting brazing benefit is employed to achieve an improved load-bearing performance of the dissimilar AA2024-T3/copper joint via the use of Dieless Friction Stir Extrusion-Brazing (DFSE-B). A comparative study of the Dieless Friction Stir Extrusion-Brazing (DFSE-B) and Friction Stir Spot Welding-Brazing (FSSW-B) of the dissimilar AA2024-T3/Cu joint was investigated by using a 100 µm thick Zn interlayer. The microstructure, tensile-shear load, and fracture modes of the respective joints were examined. The results show that Zn solidification-induced voids are inevitable at the brazed zones of both joints and the DFSE-B process suppresses flow-induced defect, unlike the FSSW-B process. An improved tensile-shear load with a significant toughness is achieved by the DFSE-B process due to the absence of tool-induced keyhole, and the intrinsic mechanical interlocking of the softer Al alloy into the harder Cu alloy. The DFSE-B is a suitable welding alternative for reactive metals.

3D printing, also called additive manufacturing (AM), is a method of creating 3D solid parts from a digital document. By utilizing additive routes, the fabrication of 3D-printed objects can be made. These layers can be viewed as a gently cut level cross-area of the manifest object. 3D printing is somewhat in obstruction to subtractive manufacture, which is expelling/discharging out a touch of metal or plastic for the occurrence of a milling machine. 3D printing authorizes creating multifarious profiles employing fewer materials than conventional fabrication systems. This review article provides the general idea of 3D printing production techniques, materials used, and applications in the aircraft and automobile industry and biomedical fields.

An improved method for detecting abnormal oceanic in situ temperature and salinity (T/S) profiles is developed. This procedure extends previous method developed by Udaya Bhaskar et al. [2017].This method utilizes World Ocean Atlas 2013 gridded climatology which is on 0.25° x 0.25° resolution to build α convex hulls. These α shapes are then used to categorize good and bad in situ T/S data profiles. This extended method classify the entire profiles instead of data for standard depths to avoid any errors introduced by interpolation to standard depths. Like in previous method, an 'n' sided polygon (convex hull) encompassing the T/S profile data is constructed using Jarvis March algorithm and Points In Polygon (PIP) principle is employed to judge the profile as good or bad. Extensive sensitivity experiments were done for arriving at the optimal α value such that false positives and true negatives are minimized. All types of issues associated with the in situ oceanographic data are identified and quality flag assigned. Examples of this improved method as applied to few Argo floats are presented. • The T/S profiles corresponding to region of interest are used to build α convex hulls. • This extended method can be effectively used for quality control of entire profile and clearly demarcate the profile as good/bad. • This method has the advantage of treating bulk of oceanographic in situ profiles data in a single go which filters out erroneous profile data from the good.

Aluminum alloys with silicon, magnesium, and copper were extensively used alloying elements in various applications because of their excellent properties. In recent decades, aluminum matrix composites (AMCs) are an advanced engineering material widely utilized in diverse engineering applications, including aircraft, automobile, marine, and shipbuilding, owing to their low density, lightweight, good stiffness, superior strength, and good tribological properties. Aluminum is abundant and its use is as vast as the ocean. It is also the most used matrix material in the composite arena. Therefore, incorporating a ceramic particle into a relatively soft aluminum matrix improves hardness, strength, stiffness, creep, fatigue, and wear properties instead of the conventional materials. This article is an assay to review and spotlight some recent works on the mechanical behaviors of aluminum-based titanium diboride reinforced metal matrix composite. This review article concentrates on the mechanical properties and the fabrication processes of Al-TiB2 composites to provide a valuable reference to nurture future research precisely.

The replacement of substances that favor the manufacturing of utility blocks ingredients is unpredictable in modern research. The experimental approach structured for the present investigation considered partial substitution of the cement mantle of a concrete matrix with dried fly ash sediment powder. As exploring innovation in being treated, dye wastewater is used in place of precious potable water for preparing mix ratio. The experimental outcomes were strongly supported by a regression representation at a macrolevel analysis and a scanning electron microscopy analysis at a microstructural level. The correlation coefficient of the developed mathematical models exhibited a dependable correlation of more than 90%. This shows the reliability of the developed regression equation for base strength predictions. Accordingly, the eventual safer and optimal limit of proportioning such a foreign matter like the dried fly ash sediment powder usage is controlled, not exceeding 9% by weight of cement mantle. However, due to the infused sediment particles within the treated effluents, the potable water is 100% replaced without sacrificing the basic quality. The administration of this dye effluent in artificially constructed wetland methods is designed for sustainable water conservation.

AA5052 bead-on-plate processing has been achieved by the friction stir processing (FSP) technique to examine the manipulation of process parameters. It also improved the base metal surfaces to analyze the microstructure. The tool spinning speed, traverse speed, and axial load were preferred to investigate the effect of friction stir bead-on-plate processing on the tensile strength qualities and microhardness in AA5052. An optical microscope was used to dissect the fabricated processed zones of the microstructure. By using the design of the experiment, the orthogonal array of the L9 Taguchi method was used to construct the processing experiments. The analysis of variance and the signal-to-noise ratio methods were employed to identify the optimum unification of process parameters and the significant benefaction of a specific parameter on the responses. The outcomes showed that the tool spinning speed was the principal factor affecting the characteristics of tensile strength and microhardness, succeeded by the traverse speed and axial load. The intermetallic compound layer had formed during the processing under specified conditions. This examination revealed that the optimum parameters could intensify the mechanical behaviour of AA5052.

Aluminium-reinforced composites play a vital role in the engineering industry because of their better strength and stiffness. The properties are directly related to the solidification phenomenon of the cast alloy. The design engineer should understand the importance of the solidification behavior of base alloy and its reinforcement. Composites’ solidification study is rare, and the reviews are limited. The solidification process is analyzed using the finite element method (FEM), and this would fetch a lot of information about the cooling rate of the composites and also helps to reduce the time in experimentation. This paper reports and plots the cooling curves of Al/SiCp composites using simulation software. Cylindrical-shaped composites were developed using the squeeze casting method, and the experimental cooling curves were plotted using a K-type thermocouple. Composites samples were prepared at the following squeeze pressures: 0, 30, 50, 70, 100, and 130 MPa; melt and die temperature was kept constant at 800 and 400°C, respectively. The experimental and FEA cooling curves were compared, and it was agreed that the increase in the squeeze pressure increases the cooling rate of the developed composite. Furthermore, the effect of temperature distribution from the inner region of the melt and die material which causes the radial and tangential stress of components has also been examined.

Aluminium and its alloys play a significant role in engineering material applications due to its low weight ratio and superior corrosion resistance. The welding of aluminium alloy is challenging for the normal conventional arc welding processes. This research tries to resolve those issues by the Tungsten Inert Gas welding process. The TIG welding method is an easy, friendly process to perform welding. The widely applicable wrought aluminium AA8006 alloy, which was not considered for TIG welding in earlier studies, is considered in this investigation. For optimizing the number of experiments, the Taguchi experimental design of L9 orthogonal array type experimental design/plan was employed by considering major influencing process parameters like welding speed, base current, and peak current at three levels. The welded samples are included to investigate mechanical characterizations like surface hardness and strengths for standing tensile and impact loading. The results of the investigation on mechanical characterization of permanent joint of aluminium AA8006 alloy TIG welding were statistically analyzed and discussed. The 3D profilometric images of tensile-tested specimens were investigated, and they suggested optimized process parameters based on the result investigations.

Nowadays, most of the products are used in the electrical and electronics field, and copper alloy is playing a significant role such as Springs for relay contacts and switchgear, Rotor bars, and Busbars. In this work, the copper alloys consider as base alloy, and the reinforced factor of silicon nitride (Si3N4) is processed of reinforcement as 3 wt. %, 6 wt. %, 9 wt. %, 12 wt. % Si3N4 through powder metallurgy performance. The ball mill process is used for this work to obtain an enhanced homogeneous mixture of both base material as well as reinforced particles. Using a hydraulic press, the blended powders are compacted with applying 3 kN and 10 min period for obtained good strength of green compact specimens. Further, the green compacted specimens are sintered, and the sintered billets are machined in the conventional lathes with different cutting speeds 50 m/min, 100 m/min, and 150 m/min; feed rate of 0.1 mm/rev (fixed); and depth of cut of 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, and 1.6 mm. Cutting speed and depth of cut to find the composites’ cutting force is ingenious. A wear test also can be conducted to find the wear resistance of the reinforced particles of the copper alloy material.

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.

In the past two decades, the Argo Program has collected, processed, and distributed over two million vertical profiles of temperature and salinity from the upper two kilometers of the global ocean. A similar number of subsurface velocity observations near 1,000 dbar have also been collected. This paper recounts the history of the global Argo Program, from its aspiration arising out of the World Ocean Circulation Experiment, to the development and implementation of its instrumentation and telecommunication systems, and the various technical problems encountered. We describe the Argo data system and its quality control procedures, and the gradual changes in the vertical resolution and spatial coverage of Argo data from 1999 to 2019. The accuracies of the float data have been assessed by comparison with high-quality shipboard measurements, and are concluded to be 0.002°C for temperature, 2.4 dbar for pressure, and 0.01 PSS-78 for salinity, after delayed-mode adjustments. Finally, the challenges faced by the vision of an expanding Argo Program beyond 2020 are discussed.

With the advent of the industrial revolution 4.0, the goal of the manufacturing industry is to produce a large number of products in relatively less time. This study applies the Taguchi L27 orthogonal array methodological paradigm along with response surface design. This work optimizes the process parameters in the turning of Aluminum Alloy 7075 using a Computer Numerical Control (CNC) machine. The optimal parameters influenced the rate of metal removal, the roughness of the machined surface, and the force of cutting. This experimental investigation deals with the optimization of speed (800 rpm, 1200 rpm, and 1600 rpm) and feed (0.15, 0.20, and 0.25 mm/rev) in addition to cutting depth (1.0, 1.5, and 2.0 mm) on the turning of Aluminum 7075 alloy in a CNC machine. The outcome in terms of results such as the removal rate of material (maximum), roughness on the machined surface (minimum), along with cutting force (least amount) were improved by the L27 array Taguchi method. There were 27 specimens of Al7075 alloy produced as per the array, and the corresponding responses were measured with the help of various direct contact and indirect contact sensors. Results were concluded all the way through diagrams of main effects in favor of signal-to-noise ratios and diagrams of surfaces with contour diagrams for various combinations of responses.

The Indian Ocean is warming faster than any of the global oceans and its climate is uniquely driven by the presence of a landmass at low latitudes, which causes monsoonal winds and reversing currents. The food, water, and energy security in the Indian Ocean rim countries and islands are intrinsically tied to its climate, with marine environmental goods and services, as well as trade within the basin, underpinning their economies. Hence, there are a range of societal needs for Indian Ocean observation arising from the influence of regional phenomena and climate change on, for instance, marine ecosystems, monsoon rains, and sea-level. The Indian Ocean Observing System (IndOOS), is a sustained observing system that monitors basin-scale ocean-atmosphere conditions, while providing flexibility in terms of emerging technologies and scientificand societal needs, and a framework for more regional and coastal monitoring. This paper reviews the societal and scientific motivations, current status, and future directions of IndOOS, while also discussing the need for enhanced coastal, shelf, and regional observations. The challenges of sustainability and implementation are also addressed, including capacity building, best practices, and integration of resources. The utility of IndOOS ultimately depends on the identification of, and engagement with, end-users and decision-makers and on the practical accessibility and transparency of data for a range of products and for decision-making processes. Therefore we highlight current progress, issues and challenges related to end user engagement with IndOOS, as well as the needs of the data assimilation and modeling communities. Knowledge of the status of the Indian Ocean climate and ecosystems and predictability of its future, depends on a wide range of socio-economic and environmental data, a significant part of which is provided by IndOOS.

The seasonal variation of thermal, haline, net surface buoyancy flux, the Monin-Obukhov length (M-O length, L) and stability parameter, i.e. the ratio of M-O length to mixed layer depth (h) were studied in the Bay of Bengal (BoB) and the Arabian Sea (AS) for the years 2003 and 2004 using Argo temperature and salinity profiles. The relative quantitative influence of winds to surface buoyancy and the applicability of scaling mixed layer using M-O length in BoB and AS was brought out. Rotation and light penetration modify the mixed layer depth from M-O length during shoaling in spring giving L/h

Every day, huge numbers of instant tweets (messages) are published on Twitter as it is one of the massive social media for e-learners interactions. The options regarding various interesting topics to be studied are discussed among the learners and teachers through the capture of ideal sources in Twitter. The common sentiment behavior towards these topics is received through the massive number of instant messages about them. In this paper, rather than using the opinion polarity of each message relevant to the topic, authors focus on sentence level opinion classification upon using the unsupervised algorithm named bigram item response theory (BIRT). It differs from the traditional classification and document level classification algorithm. The investigation illustrated in this paper is of threefold which are listed as follows: (1) lexicon based sentiment polarity of tweet messages; (2) the bigram cooccurrence relationship using naïve Bayesian; (3) the bigram item response theory (BIRT) on various topics. It has been proposed that a model using item response theory is constructed for topical classification inference. The performance has been improved remarkably using this bigram item response theory when compared with other supervised algorithms. The experiment has been conducted on a real life dataset containing different set of tweets and topics.

Air pollution is one of the serious problems faced by the people globally, especially in urban areas of developing countries like India. All these in turn lead to an increase in the air pollution levels and have adverse effects on the health of people and plants. In any well planned urban set up, industrial pollution takes a back seat and vehicular emissions take precedence as the major cause of urban air pollution. The unplanned growth of cities in India has led to the problems of increasing slums, vehicular traffic and air pollution. Automobile exhaust, which also consists of all major air pollutants is a significant source of air pollution in the urban context. The present paper deals with the study on concentration of major air pollutants from vehicles and their influence on local biota like plants and human beings in Tiruchirappalli city besides this the impact on plant species and human health has been undertaken.