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Blood pressure (BP) measurement is an important physiological parameter for human health monitoring, which plays a significant role in the diagnosis of many incurable diseases. However, due to inaccuracies in the different types of BP measuring devices, the calibration of these BP measuring instruments is a major concern for a medical practitioner. Currently, these devices' calibration, testing, and validation are performed using rigorous methods with complex clinical trials and following the available documentary standards. This article describes the design and development of an indigenous mechanical test bench (MTB) system for the testing and calibration of multiple BP devices, as per International Organization of Legal Metrology (OIML) recommended documents e.g., OIML R 16-1 and OIML R 16-2. The developed system can test and calibrate 20 BP devices, simultaneously. The traceability of the developed MTB is established by performing its calibration against the Air Piston Gauge, a national primary vacuum standard. The estimated expanded measurement uncertainty evaluated is found to be ±0.11 mmHg, which is almost one order better than the measurement uncertainty required for the test and calibration of BP measuring instruments as per standard. The MTB has successfully been used to test and calibrate several BP measuring instruments. The data of one such device is reported herein as an indicator of the performance process. The calibration of these BP measuring instruments was performed in the static mode, and the estimated expanded measurement uncertainty was found to be ±1.25 mmHg. The developed MTB system would prove to be an excellent instrument for calibration laboratories, hospitals, regulatory agencies, and other users to test and calibrate 20 BP measuring devices simultaneously and cost-effectively. [ABSTRACT FROM AUTHOR]

This paper demonstrates the design and development of a trapezoidal-shaped force transducer with simple assembly to accommodate easy strain gauging on flat surfaces. Finite element analysis has been performed for computational studies. The design is validated based on experimental results. Force metrology has been discussed in detail following the standard procedures as per ISO 376: 2011. Metrological investigation for category D (includes reversibility and interpolation) shows that the proposed design of the force transducer, achieved class 0.5 standards of force transducers with uncertainty in the measurement of only up to 0.10 % or better throughout at a nominal capacity of 15 kN (tensile load). The methodology proposed here paves way for future efforts to develop miniaturized strain gauged force transducer for a wide range of micromachining and similar other precision engineering industrial applications. Force measurement is an integral part of various industrial applications that require installation of force transducers. Sometimes, these transducers are required for on-site calibration of large testing machines. So, the current research work discusses and describes the designing of dialgauge as well as strain-gauge arrangements of measuring of applied force. [ABSTRACT FROM AUTHOR]

Force transducers have prominently been utilized in numerous scientific, industrial and metrological applications since decades. They have been developed for the measurement of force in lower as well as the higher capacity to fulfil the industrial and technological requirements. Generally, a force transducer is calibrated as per standard process. For the better perceptive, there is a need of well defined calibration procedure in an organized structure according to standard ISO 376-2011. Also, factors affecting the uncertainty of measurement using law of propagation (LPU) method and their analysis have been discussed. The relative uncertainty contributions due to different factors have been explained with suitable mathematical expression. An alternative approach for evaluating uncertainty of measurement is Monte Carlo Simulation Method (MCS) that assigns probability distribution function (PDF) to input quantities and output. Efforts have been accomplished to determine uncertainty of measurement of force transducer using both methods. [ABSTRACT FROM AUTHOR]

Recent observations of Type Ia supernovae (SNe) by SH0ES collaboration (R11 and R16) diverge from the value reported by recent CMBR observations utilising the Planck satellite and application of the Λ C D M cosmological model by at least 3 σ. It is among the most challenging problems in contemporary cosmology and is known as the Hubble tension. The SNe Ia in R11 and R16 were calibrated through cepheid variables in three distinct galaxies: Milky Way, LMC, and NGC4258. Carnegie Hubble Program (CHP) observations of type Ia SNe calibrated using the tip of the red giant approach yielded a somewhat different estimate for the Hubble constant. This decreased the Hubble tension from over 3 σ to below 2 σ. It is a legitimate question to answer whether there are any issues with SNe Ia calibration and to investigate whether the Hubble tension is real or not. We use statistical techniques namely, ANOVA, K-S test, and t-test to examine whether the cepheid calibration is host-dependent. Our analysis shows that (i) both R11 and R16 data suffer from non-Gaussian systematic effects, (ii) H 0 values in the sub-samples (different anchor-based) in both R11 and R16 groups are significantly different at a 99% confidence level, and (iii) neglecting the metal-rich MW sample does not reduce the H 0 value significantly, and thus Hubble tension persists. A small reduction in the Hubble constant could be linked to the differences in the host environment. Hence instead of using a single universal relation environment based slope and zero point should be preferred. [ABSTRACT FROM AUTHOR]

Though various types of force transducers have been developed over many years, research is continuing through the globe regarding the development of different types of force transducers. The present paper discusses the development of square ring shaped force transducers and their metrological characterization based on the calibration procedures according to standards ISO 376:2004 and IS: 4169-1988 (reaffirmed 2003). The force transducers have been developed as a modification of ring shaped force transducers and strain gauges have been mounted on suitable locations. The force transducers have been studied analytically and computationally. The force transducers are found to have good metrological characteristics and further efforts are being focused on improving the metrological characteristics of force transducers. [ABSTRACT FROM AUTHOR]

The present paper is an attempt to study the long term uncertainty of 1 MN hydraulic multiplication system (HMS) force calibration machine (FCM) at the National Physical Laboratory, India (NPLI), which is used for calibration of the force measuring instruments in the range of 100 kN - 1 MN. The 1 MN HMS FCM was installed at NPLI in 1993 and was built on the principle of hydraulic amplifications of dead weights. The best measurement capability (BMC) of the machine is ± 0.025% (k = 2) and it is traceable to national standards by means of precision force transfer standards (FTS). The present study discusses the uncertainty variations of the 1 MN HMS FCM over the years and describes the other parameters in detail, too. The 1 MN HMS FCM was calibrated in the years 2004, 2006, 2007, 2008, 2009 and 2010 and the results have been reported. [ABSTRACT FROM AUTHOR]

Abstract: Since November 2010, NPL India’s force scale has been complemented in the range from 10kN to 1MN by a further force standard machine. This automatically working 1MN force standard machine utilizes a lever amplification of a 100kN mass stack and enables low relative expanded uncertainties of smaller than 9×10−5 on the lever, and 2×10−5 on the deadweight side. In this paper, the constructional design of the machine is described. According to the new EURAMET Calibration Guide, a model for the uncertainties is developed. Supplementary to this, results from comparison measurements of the new NPL India machine with PTB´s force standard machines are presented. [Copyright &y& Elsevier]

Continuously growing technologies and increasing quality requirements have exerted thrust to the metrological institutes to maintain a high level of calibration and measurement capabilities. Force, being very vital in various engineering and non - engineering applications, is measured by force transducers. Deviations in the values observed and mentioned in the calibration certificate for force transducers may primarily be due to the creep, time loading effect and temperature effect if not properly compensated. Beside these factors, machine interaction, parasitic components etc. pertaining to the quality of the force standard machine used for calibration also contribute to the deviations. An attempt has been made by National Physical Laboratory, India (NPLI) to automate the 50 kN dead weight force machine to minimize the influence of factors other than the factors related to the machine itself. The calibration of force transducers is carried out as per the standard calibration procedure based on standard ISO 376-2004 using the automated 50 kN dead weight force machine (cmc ± 0.003% (k=2)) under similar conditions both in manual mode and automatic mode. The metrological characterization shows improved metrological results for the force transducers when the 50 kN dead weight force machine is used in automatic mode as compared to the manual mode. [ABSTRACT FROM AUTHOR]

The present paper discusses the stability studies carried out on a small number of torque transducers over the years with capacities ranging from 10 Nm to 1000 Nm. The torque transducers have been calibrated using the torque standard machine based on the written standard calibration procedure. The study reveals that the uncertainty of measurement of torque transducers has been varying appreciably and it is more for lower range. Besides, the deviation from their average values has also been studied and found to be varying through the years. [ABSTRACT FROM AUTHOR]