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An analysis is performed to examine trends in temperature, relative humidity, and wind-speed over the Indian landmass and in the isles of Lakshadweep (Arabian Sea side) and Andaman and Nicobar (Bay of Bengal side) over the last four decades (from 1981 to 2021). MERRA data deployed for revealing the large-scale fluctuations and linear trends in these parameters covering 36 locations. Surface temperature (2 m above ground) data showed a linear rise, which is more prominent after 2000, both in the Arabian side and the Bay of Bengal. Over this period, temperature increased ~ 0.7–0.8 °C on both sides of Indian landmass. About two third locations (24 locations) in the study showed increase in temperature. However, relative humidity data on all island locations exhibited a decrease (prominent during 2000–2021). Quasi-periodic fluctuations in temperature (which is linearly rising) closely relates with the ENSO parameter (correlation coefficient ‘r’ in Arabian Sea and Andaman and Nicobar ranged from ~ 0.20 to 0.34; which is statistically significant and relatively larger towards Andaman Islands). ‘r’ increased considerably (> 0.5) during 2000–2021. Wind-speed, in general, showed larger magnitude over Andaman and Nicobar Islands (~ 5.0 m/s yearly averaged) in comparison to Arabian Sea (~ 4.0 m/s) and landmass (~ 2.2 m/s). On the other hand, solar cycle (sun spot numbers) and wind-speed reflects a weak positive correlation coefficient (< ~ 0.40) but statistically significant while no consequential correlation found between solar cycle and relative humidity. Detailed analysis suggests that relative humidity decreased both over landmass and islands during 2000–2021. Interestingly, surface temperature increased more rapidly between latitudes 7.03°N and 12.91°N after 2000. Rise in temperature and long period fluctuations (> 2–3 years) in the lower latitudes (< 15°N) showed a strong association with ENSO signal suggesting invigorated atmosphere ocean interaction.

The road transport sector in India is a significant contributor to the country’s GHG emissions inventories, so it is essential to develop a comprehensive database of emission inventories to inform the design and implementation of suitable technologies and policies for appropriate mitigation measures. The development of an inventory using all available data can be useful in developing policies and technologies for reduced GHG emissions from the road sector. The paper seeks to develop an inventory of GHG emissions from the India’s road transport sector and analyse the fuel consumptions usage during the recent decade period, i.e. 2011 to 2021. In this study, IPCC guideline Tier-I and Tier-II were adopted for the emission estimation. Country-specific emission factor (EF_CS) was developed based on carbon content and corresponding net calorific value (NCV) of country-specific fuel usage. The CO_2eq emissions are also measured and compared with the corresponding global warming potentials (GWP). It appears that emissions of CO₂ equivalent emission (CO_2eq) from multiple greenhouse gases have significantly increased from 2011 to 2021. Estimation based on carbon country-specific emission factor shows nearly 165.09 Mt in 2011, increasing to about 241.20 Mt in 2021. Hence, it has been observed nearly 4.39% of reduction in CO_2eq emissions using EF_CS in the year 2021. Similar decreasing trends have also been observed for other gases like CH₄ and N₂O. The development of a comprehensive national GHG inventory for the road transport sector in India is a critical step towards achieving the country’s climate change goals and ensuring a sustainable future for generations to come.

The current trend indicates a rapid rise in electricity demand within the power generation, transmission, and distribution sectors. Among the critical facets of power systems, stability stands out as paramount. This crucial stability factor guarantees the continuous operation of systems that may encounter disruptions, faults, abrupt load fluctuations, voltage instability, voltage fluctuations (both swells and sags), harmonics, and variations in frequency while maintaining a stable state. Voltage and frequency fluctuations, along with various other issues stemming from instability in electrical power systems, pose the potential for system failure and damage. Distribution networks, in particular, are grappling with significant power quality challenges due to the unregulated utilization of diverse linear and nonlinear loads. These loads, exemplified by solid-state controllers, introduce harmonics and reactive currents into the alternating current (AC) mains. This detrimental impact on power quality, manifesting as voltage sag, voltage swell, voltage notching, flickering, and phase unbalance, can result from such practices in AC power sources. In the realm of three-phase distribution systems, the incorporation of nonlinear loads on the distribution network has given rise to a multitude of power quality concerns. This study provides a comprehensive analysis of the various power quality difficulties that have arisen as a consequence. These concerns related to power quality are evident in both three-phase three-wire and three-phase four-wire systems, encompassing notable obstacles associated with excessive reactive power demand, uneven loads, and inadequate voltage control. An essential aspect to underscore pertains to the primary limitation noted in the three-phase, four-wire distribution setup, which concerns an excessive flow of current through the neutral conductor. To address issues associated with reactive power and other facets of power quality in the distribution network, a specialized custom power apparatus referred to as a distribution static compensator (DSTATCOM) is utilized for remediation. The primary emphasis of this study revolves around the incorporation of DSTATCOM into three-phase distribution systems. An unconventional energy source, frequently represented by a solar cell, is directly linked to a static synchronous compensator (DSTATCOM) situated adjacent to the DC-link capacitor. This setup is designed to achieve the goal of resolving power quality concerns within the distribution system. The mitigation of neutral current is achieved by employing transformers in conjunction with a distribution static compensator.

This study investigates the applicability of Metrology 4.0 (M4.0) technologies for manufacturing industries (MIs). The study employed a mixed-methods design whereby sixty MIs participated fully. The convergent parallel design was employed to collect, analyse, and integrate qualitative and quantitative data and results simultaneously. Minitab® version 21, Microsoft® Excel 2016, and SPSS® software collaboratively performed inferential and descriptive analyses. The results indicate a high level of awareness within MIs. MIs have implemented M4.0-related operations at the preliminary stage. Regarding the general M4.0, respondents are very unsatisfied with how their enterprises apply the metrological-related technologies by 6.65%, unsatisfied (23.33%), satisfied (56.67%), and very satisfied (13.33%). Respondents are very satisfied with how their enterprises undertake metrological activities (operations) by 16.67%, satisfied (26.67%), unsatisfied (33.33%), and very unsatisfied (23.33%). Despite these findings, the readiness level was 3.0 out of 5.0. There is room for transiting Metrology 3.0 to M4.0, thus requiring the transition framework. M4.0 can influence accruing benefits and motivations: pattern approval in metrology, improving standardisation, digitalise traceability, argument human intelligence, product improvement, managing measurement uncertainty, enhancing digital accreditation, assisting with a virtual inspection, automating quality checks, verification enabling, assisting predictive and data analysis, speeding up calibration, and assist in decision-making.

National time dissemination using terrestrial ethernet and optical fiber cables is an alternative to satellite-based systems and provides redundancy to reliable time services for critical infrastructure in the country. Precision time protocol based on IEEE 1588 standards using such cables and fibers can provide sub-microsecond time synchronization between a provider and the client. The method employs hardware time stamping, dedicated traffic-free fiber links, and PTP-aware network elements. We present a proof of concept experiment for the distribution of Indian standard time using the IEEE protocol in a laboratory and the effect of introducing a PTP-supported switch on the distribution performance. Further, we report on the observed synchronization when an underground dark telecom optical fiber lying outside the laboratory in the central Delhi region is used as the medium of communication. The short-term one-second pulse–pulse jitter is found to be around 2.5 ns without any drift during the measurement period.

The deep groove ball bearing system local defect is investigated using a vibration model proposed in this paper. The model accounts for the masses of the housing, shaft, races, balls, damping, and race faults. The model proposes a piecewise response function that depends on the ratio of the defect size to the ball size. Analysis and discussion have been conducted on the impact of various defect sizes on measured load distribution. This mathematical model is solved using MATLAB and vibration responses are simulated for the bearing system. Experiments have been carried out, and the findings have been compared with simulation results to validate the simulation results. The comparison demonstrates that the features depicted in the simulated and experimental data are in agreement.

The butt joints of AA2099-T86 alloy were prepared by friction stir welding process under four different environments, i.e. conventional (C-FSW), liquid nitrogen (LN-FSW), ultrasonic vibration welding (U-FSW), and ultrasonic vibration with liquid nitrogen (ULN-FSW). The welding tool rotational speed of 650 rpm and tool traverse speed of 80 mm/min were fixed for all experiments. The microstructural characterization of the welded samples is examined with optical microscopy, SEM, and XRD. Higher tensile strength and microhardness were obtained in the ULW-FSW welded samples. The ultrasonic vibrations promote plastic deformation and material mixing, increasing the dislocation density and improving the weld strength. In addition, liquid nitrogen restricts the grain size and dissolution of strengthening precipitates due to the rapid welding cooling rate, resulting in higher hardness. Comparative analysis of weld joint efficiencies revealed that the ULN-FSW welded sample achieved an impressive efficiency of 87.12%. In contrast, U-FSW, LN-FSW, and C-FSW displayed efficiencies of about 86.17%, 83.01%, and 74%, respectively.

This proposed paper delves into the challenges within the metrology sector and proposes innovative solutions employing cutting-edge technologies such as AI and Big Data. The aim is to establish an AI-enabled National Digital Grid for Metrology in the context of India. In our modern digital landscape, technologies like Big Data, AIoT (AI + IoT), Cloud Computing, and Blockchain significantly influence individuals, objects, and global economies. Metrology, as the scientific study of measurement, is not exempt from these technological impacts and encounters numerous challenges in its digital evolution. As an essential component for international trade, the development of its digital quality infrastructure is imperative, prompting discussions on the numerous challenges faced in this realm. The paper explores key findings and contributions concerning the digital transformation of metrology and its significance for the sector's advancement.

This paper evaluates the performance of various PWM techniques for a 3-level inverter-based shunt active power filter by statistical parameters. It is well stated in the literature that the uses of power electronics-based devices create several power quality problems, such as poor power factor, harmonics in source current, poor voltage regulation, etc. Shunt active filters effectively alleviate these issues. A 3-level inverter, as a compensator depletes the harmonics in a single-phase grid-tied system. Level-shift, phase-shift, and hybrid PWM techniques generate switching pulses for 3-level inverter operation. These PWM techniques are compared for harmonic distortion at the source current, input power factor, and active filtering efficiency by statistical parameters such as mean squared error, root-mean-squared error, mean absolute deviation, mean absolute percentage error, standard deviation, variance, mean absolute error, and mean relative error. The above statistical parameters have been used to determine the optimum PWM technique for shunt active power filter operation. It is revealed from the results that for the PS PWM technique, the MSE is found to be less, i.e., 0.049441, and also has a low THD, i.e., 1.22% in source current. The behaviour of these PWM schemes is analysed through MATLAB/Simulink 2021b software. This paper contributes extensive information on PWM schemes for 3-level inverter-based compensator. It will help to comprehend various aspects of the power quality of a single-phase distribution system.

The depth measurement scale of the hardness test must be verified with an accuracy of 0.0001 mm. A novel optical setup is designed and developed using a flat mirror interferometer and indigenously fabricated fixtures to calibrate a Rockwell tester. One needs to repeatedly move and position the indenter of the machine to the pre-decided scale markings for calibrating the displacement to achieve the recommended accuracy. Usually, the spindle of the Rockwell tester cannot be precisely moved to a desirable position. To avert this hurdle, the measurements are taken in the time-based mode of a commercial displacement measuring laser interferometer. A new algorithm is devised to remove the unwanted readings from these time-based measurements. The deviations of the depth measuring system of the Rockwell tester are determined by applying the proposed algorithm. Further, the uncertainty of measurement associated with the displacement of the Rockwell tester is estimated.