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

This work regarding the design and development of EN 24-grade steel-based force transducer has been reported along with its metrological features in line with ISO 376:2011 standard. The force transducer has been designed on the basis of analytical and computational methodology and validated through experimental observations. The force transducer presents ease of design-cum-manufacturing and practically

From past many decades, the integrating nephelometers are generally used to measure the aerosol scattering coefficient for ground level at different wavelengths. In recent years, the research focus has been shifted toward the airborne observations using either tethered balloons or drones. For this particular purpose, one needs light-weight instruments which are capable of measuring the aerosol scattering

In order to establish traceability of area of pressure measurement, piston–cylinder assemblies are characterized dimensionally. Piston, cylinder and master ring gauges demand diameter measurement uncertainty of about 30 nm. As focused efforts to achieve the requisite uncertainty, most of the trendy diameter measuring machines, used and available across the globe, are studied for their designs and performance

Measurement standards and metrological activities provide scientific and metrological infrastructure in the country. The Pressure and Vacuum Metrology (PVM) activity has a major role in national and international metrological research and development. The PVM group is successfully providing national calibration and measurement services and fulfilling its national duty as per the mandate of CSIR-National

Photomultiplier tube (PMT) is widely used in photon counting systems because of its gain and low light sensing capability in discrete photon region. PMT-based photon counters are used in various fields such as medical, particle counting and sizing, and pollution-level monitoring. The output of photon counter is highly influenced by discriminator threshold, PMT gain and PMT operating temperature. Inappropriate

The main goal of the study was to determine the sensitivity of optical measuring system for the determination of optimal reversible two-speed planetary gear train for machine tool gearboxes. The sensitivity could be determined by different experimental approaches but in this article adaptive neurofuzzy inference system (ANFIS) was used. This approach is useful to avoid complicated physical interactions

Breath alcohol analyser is used to detect alcohol content in end-expiratory breaths in order to enforce driving regulations under the influence of alcohol legislation. The accuracy and reliability of the routine measurements of alcohol content performed with breath alcohol analyser can be achieved by the calibration of the breath alcohol analyser using standards traceable to SI reference material.

A study to assess the quality of drinking water sources and health conditions of the natives in a rural location of Solan District (30° 54′ 16.76′′ N, 77° 05′ 48.18′′ E) was conducted during February–May in 2018. Water samples were collected from four different sites covering two different and only sources of water supply, i.e., Bawdi (natural well) and Handpump in the village. These collected samples

Long-term measurements (2011–2018) of ambient sulphur dioxide (SO2) and meteorology were carried out at an urban site of Delhi, India, to study the seasonal and inter-annual variations of SO2 over Delhi. The average mixing ratio of SO2 was estimated as 2.26 ± 0.48 ppb for the entire study period. Mixing ratio of ambient SO2 was estimated as 2.19 ± 0.64 ppb, 2.07 ± 0.89 ppb, 2.49 ± 1.05 ppb and 2.27 ± 0

Harmful effect of harmonics is considered one of the main factors that badly affect the electricity meters’ accuracy and power quality of distribution systems. In this paper, the impact of harmonics generated by various household appliances has been investigated. Household appliances have been divided into four groups according to the similarity of their current and voltage waveforms. The appliances

Linear switched reluctance motor (LSRM) has proven its suitability in transit applications due to the advantages of direct drive, low cost and simple mechanical structure. In evolution of LSRM, its force performance is the prime concern for the manufacturers. This factor is mainly governed by its physical design. Force characteristics are quite important for obtaining precise design of the LSRM. Because

A revised interpolated DFT is proposed to estimate the harmonic parameters accurately. Firstly, a 4-order Hann self-convolving window is employed to restrain the interferences caused by spectral leakage and sidelobes. The corresponding error can be restrained at a degree of 10−15 theoretically. Then, an equidistant two-point interpolated formula is proposed to deal with the picket-fence effect. It

Monte Carlo simulation (MCS) is an approach based on the propagation of the full probability distributions. It was introduced by the Joint Committee for Guides in Metrology (JCGM) in the supplement I-JCGM 101:2008. It is used to resolve the problem of calculating measurement uncertainties of complex measurands through simulation of random variables. Further, supplement II on “Extension to any number

“The Guide to the Expression of Uncertainty in Measurement” (GUM) method has many disadvantages when evaluating the uncertainty of wind speed measured by pitot tube, and the “Monte Carlo method” (MCM) is put forward to evaluate the uncertainty of wind speed. The measured quantity value of wind speed by the S-shaped pitot tube is the research object, and the uncertainty is evaluated by GUM and MCM,

The present study demonstrates the use of a transportable anechoic chamber for conducting microphone free-field calibrations with lowest levels of uncertainty. A dedicated transportable anechoic chamber (make SPEKTRA, Germany) of internal volume of 2 m3 completely lined with wedge-shaped absorbers is utilized for free-field calibrations in the frequency range of 125 Hz–20 kHz using the substitution

Calibration standards are used for the calibration of a vector network analyzer to characterize the microwave components under test. For the direct characterization of coplanar waveguide components, two-port CPW open, short and line are proposed to complement the existing calibration techniques. The developed CPW standards are characterized in the frequency range of 10 MHz to 10 GHz. As these are planar

The deterioration of ambient air quality is one of the emerging environmental problems in developing countries of South Asia. Unplanned urbanization, population growth, degradation of vegetation cover and industrial and vehicular emissions, particularly in urban areas, have resulted in substantial rise in the level of air pollutants and emission sources. This study focused on monitoring of different

In order to explore the influence of water-vapor correction term on wind speed uncertainty, the actual measured value of wind speed by pitot tube is the research object, Firstly, the uncertainty value of the wind speed value obtained by the simplified model (discarding the water-vapor correction term) is evaluated by GUM method. Then, the MCM evaluates the uncertainty of the wind speed value obtained

Experimental observations and simulation results have shown that the dominant noise source of excess noise changes from thermal noise to shot noise with scaling of MOSFETs, and shot noise can be acted by Fermi and Coulomb suppression. But previous studies on shot noise suppression in nano-MOSFETs either ignored the suppression or just emphasized the existence of it but giving no more deep research

The technological enhancements and new startups in India have led to a tremendous increase in the power demand. The grids are being made smart, more efficient and reliable to meet not only the growing energy demands but also to prevent blackouts. The synchrophasor technology is evolving, explored and used by the power sectors for real-time measurements with phasor measurement unit (PMU) as the main

The Monte Carlo simulation (MCS) method for uncertainty evaluation of measurement results has gained popularity as an alternative to the method based on law of propagation of uncertainty (LPU) ever since the recommendation by JCGM through supplement JCGM 101:2008. In this paper, efforts have been made to compute the uncertainty in measurement of hardness in the Vickers hardness scale using MCS and