The presented paper discusses the summary of the special issue consisting of 13 peer-reviewed papers regarding Redefinition of SI Units and Its Implications. The papers discuss state-of-the-art reviews and progress made as of now and ongoing progress regarding the redefinition of SI units at different National Metrology Institutes (NMIs) and academic/research institutes across the globe. Different

The scientific research and new innovations are associated with the accurate and precise measurements which are crucial for operation of recent civilization. In order to maintain the precision and accuracy in analytical measurements, Reference Materials and Certified Reference Materials (CRMs) play a vital role for improving the measurement capability to obtain the property value close to its true

To guarantee the reliability of the measurements made with CMM, the machines must be periodically checked and calibrated, to evaluate the performance and obtain optimized measurement results. However, the main obstacles encountered to ensure these accuracies are the development and implementation of periodic calibration practices and interim checking methods that guarantee the traceability of measurements

A four-port multi-input-multi-output (MIMO) antenna is designed for the WLAN access point applications. The prospective antenna consists of four double-layered printed dipole antennas (DLPDAs), where two elements are designed to resonate at a frequency of 2.45 GHz and the resonant frequency of the other two elements is 5.8 GHz. The resonant bandwidths of the DLPDAs are 24.7% (2.09–2.68 GHz) and 28

Relative velocity feedback is a method that is used to improve the low-frequency characteristics of a standard vibration table. Under limited mechanical conditions, the distortion of the low-frequency band of the vibration table is greatly reduced by using relative velocity feedback. However, there is a resonance peak in the passband of the vibration table system. When the resonance peak is too large

The aim of this study is to assemble the data and reflect the epidemiological statistics required as well as apply mathematical prototypical approach of the new outbreak that cover all perspectives of the facts and figures as of August 08, 2020, and thereby suggest the direction of the forthcoming epidemic situation in India for all policy makers. The outburst of the new fatal strain of coronavirus

Novel grid code allows heavy penetration of wind electric power into the grid which leads to new challenges of power quality like harmonic pollution in variable speed wind turbines with asynchronous generator. The article provides an analysis of the existing methods for identifying wind farm contribution to harmonic distortion at a point of common coupling. The considered methods do not allow correct

Despite the large number of III–V semiconductor studies reported every year at bulk level, the III–V material characterization at nanoscale is still required to evaluate their potential industrial applications in nanoscale electronic devices, optoelectronic devices, chemical, biosensors, etc. In this work, the non-destructive evaluation-based ultrasonic theoretical approach for the material characterization

Atomic clocks work on a standard frequency generated by the electron transitions in the atoms of the core material. A timescale is a reference frequency and phase measure generated by a set of atomic clocks. An ensemble algorithm combines the participating atomic clocks to form a “perfect” clock. The perfect clock is very stable and precise in terms of frequency and phase. There are many methods that

The study focusses on two major aspects: measurement methodology and uncertainty in the realization and dissemination of unit watt in airborne sound and consideration in legal sound regulations for various noise sources. Although sound power level is the fundamental unit invariant of distance from the source, yet there is no direct method for its measurement. An National Metrology Institute (NMI) perspective

Length measurement has been an indispensable part of human life since the ancient era till present days. Length and area measurement got importance from very early Indus Valley civilization for construction of roads to measurement of agricultural land. In India, length measurements were defined in Indus Valley civilization and rulers had rules for length measurements. Mughal and British adopted the

The redefinitions of the seven SI base units, as approved and adopted by the 26th CGPM, now depend on the seven defining constants, respectively. Candela is one of the seven base units, which is related to the measurement of light as perceived by the human eye. It is the only base unit to be related to the human physiology and gives a physical base to the phenomenon of vision. Over the period of time

The X-ray crystal density method uses silicon spheres highly enriched in 28Si as a primary method for the dissemination of the SI base unit kilogram yielding smallest possible uncertainties associated with the mass m within a few parts in 10−8. This study compares different available and newly developed analytical methods and their results for the determination of the molar mass M of silicon highly

X-ray interferometry established a link between atomic and macroscopic realisations of the metre. The possibility of measuring the silicon lattice parameter in terms of optical wavelengths opened the way to count atoms, to determine the Avogadro constant with unprecedented accuracy, and, nowadays, to realise the kilogram from the Planck constant. Also, it is a powerful tool in phase-contrast imaging

One of the important issues in photometry and radiometry is the surface area calculation, or knowing its relative surface element for any integration or other metrology aims. In this paper, firstly, we have reviewed the oblique cross-section of a right circular cone (OCRCC), then we have derived how to choose an elementary surface area or infinitesimal small patch on the elliptical surface of OCRCC

The acceptance of the redefinition of SI units on 20 May 2019, based on fundamental physical constants of nature led to significant changes in the field of metrology. The National Institute of Standards and Technology (NIST), USA has developed a quantum pressure standard, i.e. optical interferometer manometer (OIM), which is based on the change in the refractive index/polarizability/density of gas

In this work, a microwave field is sensed by rubidium atoms instead of a conventional antenna like dipole or horn antenna. Microwave field is projected onto a glass cell containing Rb vapors which act as an antenna in this case. A four-level ladder atomic system is considered for analytical solution, and E-field measurement is reported by utilizing quantum phenomena like electromagnetically induced

In this paper, detailed geometry of the detection chamber, configuration of detection probe laser beams, data acquisition and processing techniques of the cold atoms in Cs atomic fountain primary standard at NPL, India has been discussed. The S/N ratio in the detected atom count was too low to make a valid estimate of signal. By implementing an efficient design of detection hardware (especially changing

Traceability is urgent to guarantee the truth of measurement, particularly for National Standard. Although a bell prover facility has established as the national low pressure gas flow standard of Indonesia since 2008, the measurement capability (15 to 1400 L/min, U95 = 0.20%) of the bell prover has not been traceable to SI Units. Moreover, displacement values provided by the bell prover’s manufacturer

Certified reference materials (CRMs) are used for evaluating analytical methods, quality assurance and traceability of analytical results to international standards. Bituminous coal is the medium grade coal with high heating capacity and low moisture content. CRM of bituminous coal powder (BND 5101A) has been developed and certified for ash, gross calorific value (GCV),volatile matter (VM) and total

Inductively coupled plasma mass spectrometry (ICP-MS) has become inevitable for quantitative determination of trace and ultra-trace elements in geological samples. Inferences derived from ICP-MS data sets and other supportive evidence have revolutionized theories on geology/geodynamics. In this scenario, validation through interlaboratory studies plays an important role in assuring the quality of measurements

This work presents, in brief, the recently concluded extensive in-house inter-comparison of the pneumatic pressure standards at CSIR-National Physical Laboratory, India (NPLI) and the resulting marginal improvement in our measurement uncertainties. The measurements are traceable to the Ultrasonic interferometer manometer (UIM), our low-pressure primary pressure standard as well as to the national primary

The paper presents a terse review on the evolution of measurement system and International System of Units (SI) in India, the methodology followed to realize the measurement units and the present state of the art in realizing of 7 base units. The measurement systems evolved, developed and used during several ancient historical periods, Indus valley to Vedic period to existing SI system of modern era

The melt flow index (MFI) of commercial polystyrene samples has been investigated throughout an interlaboratory comparison study. The homogeneity samples have been assessed prior to the distribution over the participants. The one-factor analysis of variance model has been applied to separate and evaluate the uncertainty components arising from the analytical method and the heterogeneity of the samples

Nowadays, most of the standards of measurement are based on fundamental constants, and among all, the SI units of time and frequency are realized with the highest precision. The SI unit of time interval, i.e. second, is realized on the basis of a hyperfine transition of ground state of 133Cesium atom in the microwave region. Atomic clocks operating at the optical frequencies have potential of providing

The article considers the issues with amount of fuel and oil measurement process for transaction purposes and makes recommendations how to manage possible losses due to incorrect measurement results of large fuel amounts. All decisions are based on the general errors theory and legal metrology requirements. The focus of the article is on company and client control measurements, static and dynamic weighing

Three-dimensional (3D) printing is an outstanding technology and performs a significant role in the fabrication of sensors as compared to conventional methods of fabrication, such as subtractive manufacturing. In this review paper, fabrication of general-purpose sensors using traditional manufacturing and 3D printing has been discussed. All possible sensors, including mechanical sensors, electronic

The present research work is the part of the feasibility study to implement non-invasive blood-glucose sensing using microwave-based sensor. The one-port microstrip patch antenna sensor developed to exhibit variation in its electromagnetic response with respect to blood-glucose level. It has been demonstrated through in vitro controlled experiment under laboratory conditions. The novel multi-parameter-based

The new definition of the kilogram was implemented on May 20, 2019. The kilogram is presently defined by a fixed value of the Planck constant. On the basis of the new definition, the kilogram will be realized at the National Metrology Institute of Japan by the X-ray crystal density method using 28Si-enriched spheres. For the realization, the volume of 28Si-enriched spheres is measured by optical interferometry

Particle Swarm Optimization technique has been improved by fractional order calculus to be used for photovoltaic (PV) modeling. The modified technique which is called Fractional Order Darwinian Particle Swarm Optimization (FODPSO) has been constructed to estimate the optimal electrical parameters of PV modules. Single and double diode models have been used to designate the PV modules. FODPSO and PSO

The redefinition of mass adopted in November 2018 and implemented from 20 May 2019, i.e. World Metrology Day, eliminated the artefact-based approach dependent upon the International Prototype of the Kilogram (IPK), in favour of realizing the kilogram in terms of the Planck constant h by fixing its value as 6.62607015 × 10−34 J s. In this paper, the authors present a general outline of the circumstances

The eccentricity, difficult to adjust for components with a large radius, can lead to roundness measurement distortion. In this paper, the effects of the eccentricity and radius of components were simultaneously analyzed in the roundness measurement. The derived mathematical relationships between roundness measurement error, eccentricity and radius of components were represented graphically. Simulation

To assess the technical competence of calibration laboratories, national accreditation bodies (NABs) take into account the results of national and/or international proficiencies testing (PTs) including the inter-laboratory comparisons (ILCs). As the Italian NAB stopped acting as PT provider since 2015 due to the result of a peer assessment by the European co-operation for accreditation, the National

A valve has a function of controlling the flow of a fluid by opening or closing a passage. A valve can thus be used to create different pressures for the two areas on either side of the valve. However, the conventional vacuum valve has a problem that the flow rate of the gas cannot be controlled. In this light, it is necessary to develop a vacuum valve that is capable of precisely controlling the flow

Proficiency testing is a vital component to ensure quality of tests and calibrations. In particular in legal metrology, the scope of activities claiming for accreditation demands for specific proficiency testing. This study presents the results of the proficiency testing conducted in 2019, in Brazil, for sphygmomanometers, an instrument usually under legal metrology regulation, whose measurements have

The profile camber angle is a key influence parameter on the aerodynamic performance of blades, the measurement of the profile camber angle is of great significance to the optimization design and the quality control for blades. In order to solve the problems in adaptability and accuracy of existing measurement methods, a form-free high-precision metrological method of the profile camber angle of blades

The fiber optic gyroscope (FOG) has a broad application prospect in the field of dynamic angle measurement. The scale factor, which is an important indicator of the FOG, directly determines the angle measurement precision. In this paper, the principles of angular velocity method and angular increment method, which have been commonly used in obtaining the scale factor, are introduced, and the error

Ultrasonic velocity is an important property for various physicochemical investigations in the liquids. The continuous wave ultrasonic interferometers are widely used as a cost-effective instrument for the estimation of ultrasonic propagation velocity. One of the critical aspects of this instrument is the level of radio frequency excitation supplied to piezoelectric transducer, which can cause heating

Metal–semiconductor (MS) contacts are main aspects of almost all electronic circuit elements. Thus, contact mechanism and its electrical properties to develop a faster and more reliable electronic device should be known. The electrical characterization of MS devices (in terms of temperature-dependent and/or independent current–voltage (I–V), capacitance–voltage (C–V) and capacitance–frequency (C–f)

Ambient air pollution is a constant and immediate threat to human health. The present study estimates the health implications of ambient air pollution in Faisalabad, Pakistan. The level of PM10, CO, NO2 and SO2 was determined in four areas of the city i.e., industrial, commercial, residential and rural, to estimate the ambient air quality of the city during the pre-monsoon and monsoon season. The ambient

An importance of data analysis, methods for homogeneity test and standard uncertainty evaluation associated in any measurement for exact quantification of certified value of any product is vital to be stressed in the scientific community. Herein, we have collectively summarized the detailed discussion on the basics of statistical parameters such as mean, median, mode, standard deviation, variance,

Clock error prediction is of vital importance for the distributed netted systems’ regular operation, like netted satellites, netted radars, etc. Aiming at the problem of predicted length could not get beforehand in some conditions, we put forth a combined clock error method under uncertain predicted length. We estimate the predicted length based on the clock error data quality factor in advance. Then

The paper evaluates the measurement uncertainty in realizing the secondary vibration standard at CSIR-National Physical Laboratory, India, and presents a comparison of the measurement uncertainty of secondary standard with that of primary vibration standard. The relative expanded measurement uncertainty of 0.80% to 2.2% in frequency range of 5 Hz to 10 kHz is evaluated. The measurement uncertainty

This study comprises a brief summary of the quantification method for measuring carbon dioxide respiration rate (CO2 RR) in wheat as well as reliability criteria for this method. Assessed accuracy characteristics of the method enabled complex evaluation of the measurement uncertainty. Mathematical model of the CO2 RR measurement was estimated and the uncertainty sources were identified. Expanded uncertainty

This article presents a nature-inspired optimization technique, namely the moth flame optimization (MFO) algorithm, for tuning the PID controller parameters in the variable range of split-range control scheme to regulate the temperature of the mixing process. Further, the performance of the controller using Ziegler–Nichols (Z–N) tuning method and MFO algorithm is compared for the same. In this study

In this feature article, the quality infrastructure (QI) of India is discussed. A national QI is comprised of internationally recognized metrology, standards and accreditation. The QI built on a technical hierarchy to ensure the accuracy and precision of measurements traceable to SI units, is basic enabling system for providing the conformity assessment (calibration and testing, certification and inspection)

In this article, in calibration process of strain cylinder, which is performed according to ISO 376 standard, effect of loading apparatus with different dimensions on measurement result has been investigated. In addition, relative repeatability error of calibration on measurement results, temperature fluctuation, accuracy error of measurements, creep error, as well as the stability and metrological

A new method has been developed and evaluated for density measurement of liquid materials based on conventional gamma density meter, whether a low strength gamma radioactive source as the backscatter technique with collimated detector cannot be properly used for density measurement. In this comparative study, proposed method aimed to improve the linearity of the density measurement without using time

A model predicting time required to attain undesired levels of respiratory-CO2 in closed rooms is described. The model works under the following assumptions: (1) room air is well-mixed, (2) indoor CO2 does not exchange with outdoor CO2, (3) there is no effect of individual occupants on CO2 exhalation rate of other occupants, (4) there is no indoor CO2 sink and all exhaled CO2 end up increasing CO2

The implementation of modern 3D scanning method for horizontal fuel tanks’ calibration applications proposes versatility and advantages over the currently used volumetric method which requires using of liquid filler (in most cases water, and in some countries—gasoline). However, the data scatter in the 3D pointcloud deteriorates the accuracy of the volume calculation algorithm output and therefore

The gas permeability of solid material is one of the important factors affecting pressure change properties of seal products. In this article, the pressure change analysis based on gas permeation and material outgassing principle of the seal cavity for satellite in-orbit is carried out. Through establishing the pressure change model of the seal cavity, analyzing the gas permeation of the encapsulating

Air quality models (AQMs) are useful for studying various types of air pollutions and provide the possibility to reveal the contributors of air pollutants. Existing AQMs have been used in many scenarios having a variety of goals, e.g., focusing on some study areas and specific spatial units. Previous AQM reviews typically cover one of the forming elements of AQMs. In this review, we identify the role

In the present communication, a systematic characterization of atmospheric turbulence simulator (ATS) based on near-index-matched optics is reported. Characteristics of the propagating laser beam in actual turbulence can be realized in the laboratory by employing such types of turbulence simulators. Such simulators are necessarily required to evaluate the performance of an adaptive optics sensor and

Metrology plays the key role as the engine of industrial revolution and growth of any country. It promotes global competence and confidence. With the advent of better quality products through metrological advancement, our industries can compete internationally and to overcome trade barriers/constraints and finally to achieve exports targets. This translates into growth of industries through rapid industrialization

Measurement, monitoring and recording of the environmental condition is the essential and sometimes statutory requirements, to observe the small change or deviation in the results of measurements in calibration and testing laboratories as well as other scientific applications. This motivated the authors to develop a precision wireless environment conditions, measurement, monitoring and recording (WEMMR)

Improving the stability of national time scale (TS) is a main target for all time keepers. The stability of TS can be improved by either increasing the number of atomic clocks in the ensemble or by adding clocks of higher stability. In both cases, a large financial budget is needed which may be unaffordable by some developing economics. In this paper, we propose a new method for improving the stability

Clustered routing protocols with static sink suffer from energy hole problem. Sensor nodes (SNs) closer to the sink node work as a conveyer for faraway nodes, and these nodes deplete their energy very fast which causes an energy hole in the network. Using the mobility of the sink node is one of the best approaches to eradicate energy hole problem and to improve the lifetime of the network in wireless

There is an increasing demand for the large-scale force standard machine with a capacity higher than 20 MN. In this paper, the calibration method and procedure were developed according to a proposed traceability route and used to calibrate a 60 MN force standard machine. One 7.5 MN and six 20 MN force transducers and two 60 MN build-up systems were used as the force transfer standards. Uncertainty

A one GPa controlled clearance piston gauge used as a high pressure standard at KRISS was investigated. In establishing the high pressure standard, the distortion coefficient is one of the most important parameters, but it is not easy to determine. The conventional analysis using a Heydemann–Welch model has a problem when determining a stall pressure, because of the nonlinear characteristic of fall

Satellite signal propagation at Ka-Band is more prone to weather effects than those with lower frequencies. The impact is more severe in the tropics because of its natural climate with heavy rainfall throughout the year. Rain attenuation prediction models developed in this region need to be evaluated to find the optimum model that suits the experimental parameter. Therefore, the main objective of this