The CSIR-National Physical Laboratory (CSIR-NPL), the National Metrology Institute (NMI) of India, is a premier laboratory, founded on January 04, 1947, under the umbrella of Council of Scientific and Industrial Research (CSIR), New Delhi, Government of India, by an Act of Parliament. It has now completed 74 glorious years after inception and entered into its 75th year, i.e. Platinum Jubilee Year.

The present article describes the design and development of a universal device for precise and accurate distribution of time or frequency signal, i.e., one pulse per second (PPS) or 10 MHz and 5 MHz sinusoidal signal generated from an atomic clock or ensemble of atomic clocks. The frequency distribution unit provides four identical outputs of excellent stability along with suppression of all high harmonics

An optical fibre link has been established for precise time and frequency transfer utilizing White Rabbit (WR) network. Temperature sensitivity of WR network components on time offset error has been studied in detail. WR node shows significant sensitivity to the ambient temperature variation when it is locked to an external reference frequency. The change in time offset between two nodes reaches up

In recent years, the performance of an interferometric fiber optic gyroscope (IFOG) has been increased a lot and widely used for dynamic angle measurement. In this paper, we present an investigation on measurement uncertainty of the IFOG and propose a comparison angular vibration calibration approach based on an IFOG. The operation principle of the closed-loop IFOG is introduced, and its error model

The present article describes an indigenous design of microcontroller-based photon counter, which is capable of counting the pulses up to maximum of 5 MHz rate. For this purpose, the short-duration pulses received have been broaden to make it compatible with the counter. The developed photon counter has been tested for its functionality to count the number of photons in a specified time bin at different

The variations of meteorological parameters have significant effects on radio wave signals propagating through the troposphere. Proper planning of radio communication links can be achieved by continuous studying of the atmosphere using refractivity profiles to provide baseline data that could be used to mitigate satellite communication outage before the onset of severe adverse hydrometeor environment

The current advances and innovations in sensor technologies attributed to Industry 4.0 serve as the backbone for the inclusive growth of industry and ramping up the economy of any country. Industry 4.0 was basically conceptualized by introducing the Internet of Things (IoT) and Information and Communication technologies (ICT) that serve as an interface between digital and physical world through the

Present work can be used to calibrate inductance standards by utilizing the error evaluated at the same nominal value of reactance of a capacitance standard. Inductance can be determined in terms of capacitance standard by direct measurement of capacitive reactance on the LCR meter. The conventional Maxwell–Wien bridge is currently used at CSIR-NPL to determine traceability to the inductance standard

The measurement of body mass index (BMI) is an important indicator of preliminary assessment of human health. A higher BMI value increases the risk factor for critical diseases, e.g., high blood pressure (hypertension), cardiovascular disease, gallbladder disease, type 2 diabetes, etc. Obesity also increases the risk factor of COVID-19 in patients. BMI, the ratio of mass (in kilogram) to the square

Precise and accurate pressure measurements play a prominent role in several scientific applications. The pressure balances (PBs) are used as a primary standard for pressure measurements which requires utmost accuracy. In the case of calibration and characterization of these PBs, the method of cross-floating is an internationally accepted practice used for the comparison of 2 PBs for determining their

Frequency modulated thermal wave imaging (FMTWI) has been successfully applied in the field of infrared thermography to estimate defects in various structural materials. The paper presents theoretical aspects of three-dimensional mild steel sample for FMTWI to detect flat bottom holes as defects. Furthermore, performance of FMTWI for analytical and simulated approach has been discussed and comparison

In a recently published report, Somak Bhattacharyya et al. 2016 presented a broadband metamaterial absorber based on a single split ring resonator. He proposed that such an absorber can achieve a broadband absorption which is from 6.70 GHz to 15.82 GHz with above 90% absorptivity. In this paper, the absorber proposed Somak Bhattacharyya et al. is recalculated again and justified that to have ignored

National metrology institute (NMIs) has the prime responsibility to design, development and maintenance of the primary pressure standards to establish the traceability chain for the calibration of the sophisticated industrial instruments using various pressure standards like ultrasonic interferometer manometer (UIM), air piston gauge (APG), force-balanced piston gauge (FPG), and optical interferometer

The paper presents a case study pertaining to the analysis of factors affecting the measurement uncertainty in primary calibration of accelerometers at lower frequencies in range of 0.1 to 40 Hz using low-frequency primary vibration calibration standard realized at CSIR-National Physical Laboratory, India. The potential high accuracy and precision in measurement are achieved with a long-stroke exciter

In the precise and accurate metrological activities, there are various types of surface plates (SPs) used in mounting or calibration purposes. It is essential to install surface plate in the laboratory with a minimum self-deformation and resultant least strain due to its own weight and mounting mechanism. Reference datum of the measuring machines, say in case of a pressure balance, requires flatness

In this article, an optical fiber-based intensity-modulated angle measurement sensor is demonstrated for the measurements of small angles in the range of − 100 to 100 arcmin. At the outset, using a step index multimode polymer optical fiber, reflection-based proximity sensor was developed and the response of it is plotted to identify the maximum response region. At this maximum response region, the

When measuring glucose concentration, assuring the reliability of the results is critical, because the clinical diagnosis of pathologies related to diabetes mellitus, as well as their medical treatment, depends on them. One of the most widely used glucose determination methods in clinical chemistry is the GOD-PAP enzymatic method. Hence, a validation process based on the theory of errors, as well as

This article deals with the ABIS II optical sensor from Carl Zeiss Optotechnik GmbH, which is used in the automotive industry to check the surface quality of moulded parts. Within the research, the process of scanning the moulded part using the ABIS II system was examined in detail, and on the basis of this, the most fundamental influences on the accuracy of the scanning and surface evaluation were

Accurate and precise measurement with authentic data dispersion can be considered as a prime tool to realize any technologies at large scale. In the context of thermoelectric technology, a combination of Seebeck coefficient (α), electrical conductivity (σ) and thermal conductivity (κ) are prominent physical parameters that dictate the performance of thermoelectric materials. In this review article

In this paper, a new neutrosophic exponentially weighted moving average (NEWMA) control chart based on the moving average statistic is proposed. Stated differently, the NEWMA chart is used to handle uncertain production numbers. Moreover, a NEWMA design is applied with moving average statistic to get a sensitive control chart for the quick detection of any unwanted process variations. The efficacy

Modern geodetic terrestrial technology involves automatized observations based on an application of robotic total stations. The benefit of such an advanced geodetic instrument is in its high precision sustainability, manipulation simplicity, maximum flexibility, one-person operability and personal error reduction. The paper is devoted to the analysis of results achieved by using such a modern geodetic

The existing Durbin–Watson (DW) test is applied when all observations are determined and certain. The Durbin–Watson test under neutrosophic statistics is presented in this test. The proposed neutrosophic Durbin–Watson test can be applied to test either autocorrelation exists in error terms when neutrosophy is presented in the data. The proposed test statistic is introduced and applied to the data that

The selection of a suitable gridding method for the interpolation of the input dataset has always been a big challenge. In this study, principal component analysis (PCA) was employed to select a suitable interpolator for the mapping of solar irradiation. For this purpose, sunshine duration data obtained from 50 meteorological stations was used to predict solar irradiation based on the Angstrom–Prescott

The study on historical and future variation in precipitation and temperature is needed to develop effective adaptation strategies for changing climate. The present study investigated the potential impacts of climate change on precipitation and temperature and the performance of individual downscaled global circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 dataset over

Modular multilevel converters (M2Cs) have become an interesting and attractive topology for DC/AC conversions and vice versa. This converter is an efficient power electronic converter for adjustable speed drives, high-voltage direct current transmission, renewable energy systems and large power supplies. For drive applications, a theoretical background is presented. This paper presents the comparative

Air Pollution from both indoor and outdoor origin contributes significantly to human exposure and is a cause of concern to citizens living in urban as well as in rural India. Today, our lifestyle demands a considerable amount of time to be spent within the indoor environment making quantification, variability and health impact assessment of indoor pollutants a necessity. Till now, sparse information

All measurements have uncertainty and they are not absolute. Therefore, identification, determination and evaluation of critical influencing factors based on recent approaches are important and necessary. Laboratories shall identify and evaluate all components and contributions to measurement uncertainty. In this article, two different approaches for evaluation of measurement uncertainty of arsenic

Single-point diamond turning (SPDT) is a machining process with high levels of profile accuracy and nanometric surface characteristics. SPDT is a leading technology in advanced manufacturing of ultra-precision optical components for critical applications. Different efforts have been undertaken to improve the cutting condition and optimize the machining parameters during SPDT. The implementation of

In analytical methods, the presence of outliers may mislead the experimenters. The existing Cochran’s tests apply to detect outliers when cent percent of observations in the data are determinate. But, when some or all observations are not precise, determined, and certain, the existing Cochran’s tests cannot be applied for detecting outliers in the data. In this paper, we introduce Cochran’s tests and

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