The phase error in a high quality accelerometer was investigated on the basis of systematic experiments on a prototype platform permitting controlled vertical harmonic oscillations. The recordings of an accelerometer and of an ultra-high frequency GPS fixed on this platform were compared with those of a LVDT transducer, controlling the platform movement. All sensors were supported by independent GPS timing. The output of this study is that the recordings of accelerometers are characterized by a random phase error, which, however, decreases with the increase of the oscillation frequency, as dictated from the laws of mechanics. Such errors are important given the increasing use of combinations of accelerometers with various sensors for a wide range of applications. A simple method for the correction of such errors is proposed.

This paper describes an approach to generating reference data sets to evaluate the performance of algorithms used in coordinate metrology for form and geometric tolerance assessment. The approach starts with the reference results, e.g., the solution feature parameter values, and then determines the coordinate data. In this way, the expensive development of reference software is avoided. In this paper we consider the generation of reference data associated with determining the best-fit surface according to the least squares (Gaussian) and Chebyshev criteria.

Carbon nanotubes (CNTs) have become strongly promising nano-particles for developingnovel smart polymer matrix nanocomposites to satisfy the ever increasing designrequirements of the recent avenues of space industry and other special structuralapplications. The objective of this paper is to investigate the influence of doped anddispersed CNTs in polymer matrix on its intrinsic properties. Three different types ofpolymers; polyvinylchloride (PVC), polymethylemethacrylate (PMMA), and polystyrene (PS)were subjected to this experimental investigation. CNTs/polymer matrix composites with acontent ratio of CNTs up to 5% by weight were synthesized in lab. The nanocomposites werethen characterized by measuring their mechanical, electrical, and thermal properties. Inaddition, thermo gravimetric analysis (TGA), Fourier transform infra red spectroscopy(FTIR), and scanning electron microscopy (SEM) were applied, and the results are presentedand discussed. It can be generally concluded that both PMMA and PS polymers disclosed muchbetter matching ability and cross linking ability with the interweaving CNTs than the PVC.Both PMMA and PS polymers may thus be nominated for further extension of the investigationto cover a wider range of CNTs content ratios in an endeavour towards searching formaximum specific performance properties of such nanocomposites.

Least squares regression is commonly used in metrology for calibration and estimation. Inregression relating a response y to a predictor x, thepredictor x is often measured with error that is ignored in analysis.Practitioners wondering how to proceed when x has non-negligible errorface a daunting literature, with a wide range of notation, assumptions, and approaches.For the model ytrue = β0 + β1   xtrue,we provide simple expressions for errors in predictors (EIP) estimators \hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP for β0 and \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP for β1 and for anapproximation to covariance (\hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP, \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP). It is assumed that there are measured datax = xtrue + ex,andy = ytrue + eywith errors ex in x andey in y and thevariances of the errors ex andey are allowed to depend onxtrue and ytrue, respectively.This paper also investigates the accuracy of the estimated cov(\hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP, \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP) and provides a numerical Bayesian alternative usingMarkov Chain Monte Carlo, which is recommended particularly for small sample sizes wherethe approximate expression is shown to have lower accuracy than desired.

A common measurement model for a gas operated piston-cylinder based pressure standardeffective area is the well known integral equation formulation originally developed byDadson of the NPL. However a problem with directly applying this exact mathematical modelis that it cannot be easily cast into a functional form suitable for application of theGuide to the expression of Uncertainty in Measurement (GUM) which is reliant on theconcept of sensitivity coefficients without various simplifications. In this paper, weexamine the standard approximations that are currently necessary in order to directlyapply the GUM for a pressure standard effective area uncertainty determination. We alsocompare and contrast this to the exact effective area uncertainty results obtained throughthe direct application of the Monte Carlo Method (MCM) which has recently been publishedas Supplement 1 to the GUM. Based on these investigations we also draw some preliminaryconclusions on the relative merits on the extent to which the shape of the piston andcylinder radii and whose uncertainties may vary along the engagement length of thepiston-cylinder may be modeled and incorporated into a piston-cylinder’s effective areauncertainty calculation.

Translating measurement uncertainty into terms of effective impact associated withmanufacture, testing and incorrect assessment gives a more “stakeholder” motivated (andultimately optimised) approach to decision-making in conformance assessment. Recentlydeveloped decision-theory tools include the “optimized uncertainty” methodology and the“operating cost characteristic”. Overall costs, E, consisting of a sum oftesting costs, D, and the costs, C, associated withcustomer risk, can be calculated with the expression:

with , whereRPV denotes the region of permissiblevalues and σ is a measure of dispersion. A complete, 3D surface ofoverall cost can indicate the optimum level of measurement effort of these two ranges, asrecently published by the author in a wide range of applications: optimized acceptancesampling; optimized testing of measurement instruments; and an analysis of optimisedcalibration intervals and “guard-banding”. This approach is illustrated in the presentwork for the example of geometrical product control in the car industry, specifically thegap in vehicle closure panels taking account of customer dissatisfaction.

A new comparison system has been constructed for the calibration of capsule-type standardplatinum resistance thermometers (CSPRTs) below 273.16 K at the National Institute ofStandards (NIS-Egypt). The system can compare two CSPRTs at once. A gold plated comparisonblock, in which CSPRTs are mounted for calibration, is made from oxygen-freehigh-conductivity copper. A description of the system and the comparison block along withthe comparison method is given. The standard uncertainty related to the temperaturecontrol of the system is estimated to be 0.04 mK. The calibrated values for CSPRTs andobtained using the comparison system are in good agreement with those obtained by thedirect realization of the low temperature fixed points of the ITS-90 within the combinedstandard uncertainty.

This study is an overview of the capability evaluation of measurement systems.Principally, the determination of capability of a measurement system is an importantaspect of quality and process improvement initiatives. In practice, various methods aredeveloped and used for determining measurement system capability. As a measurement tool,potential effectiveness of gauge should be considered and significant factors should beidentified for that purpose. A set of procedures referred to as Measurement SystemsCapability Studies are conducted for assessing capability of gauge, isolating sources ofvariability in the system, evaluating how much of total observed variability is due togauge, and investigating two components of measurement error: repeatability andreproducibility of gauge. Gauge Repeatability & Reproducibility (GaugeR&R) Study tries to estimate repeatability and reproducibility components ofmeasurement system variation with primary objective of assessing whether gauge is suitablefor intended application or not. Measurement System Analysis (MSA) is a collection ofstatistical methods, which includes Gauge R&R Study, for analysis of measurementsystem capability. In this study, detailed literature review of MSA, Gauge R&R andMeasurement Systems Capability Studies, and general discussion of misclassificationprobabilities that give useful, reliable information about measurement systems performancewould be provided.

A number of calibration techniques are used in Radio Frequency (RF) calibration for power, attenuation and impedance parameters. Mismatch uncertainty plays a major role in these measurements and in estimation of combined uncertainty according to ISO/IEC 17025:2005 and GUM document. Formulas to evaluate the mismatch uncertainty in terms of reflection coefficient, voltage standing wave ratio and scattering parameters have been evaluated earlier and are being used in RF calibration. The present paper summarizes the mismatch formulas previously studied and the modified ones suitable to the measurement system and techniques available today. For power and attenuation calibration in the particular frequency range, an establishment of traceability for one-port measurement in the same frequency range is required. The methods to reduce and control this uncertainty component and their limitations are also discussed forbest measurements practices in the calibration laboratories.

A key ingredient to underpin process improvement is a robust, reliable, repeatablemeasurement system. Process improvement activity needs to be supported by accurate andprecise data because effective decision making, within process improvement activity,demands the use of “hard” data. One of the oldest and most established process improvementmethods is Deming’s Plan-Do-Check-Act (PDCA) cycle which is reliant on the check phase, ameasurement activity where data is being gathered and evaluated. Recent expansions of thePDCA such as the Six-Sigma Define-Measure-Analyse-Improve-Control (DMAIC) methodologyplace significant importance upon measurement. The DMAIC cycle incorporates the regimentedrequirement for the inclusion of measurement system analysis (MSA) into the breakthroughstrategy. The call for MSA within the DMAIC cycle is to provide the improvement activitywith a robust measurement system that will ensure a pertinent level of data during anyvalidation process. The Lean methodology is heavily centred on the removal of the sevenMudas (wastes) from a manufacturing process: defects, overproduction, transportation,waiting, inventory, motion and processing. The application of lean, particularly withinthe manufacturing industry, has led to a perception that measurement is a waste within amanufacturing process because measurement processes identify defective products. Themetrologists’ pursuit for measurement excellence could be construed as a hindrance by the“cost down” demands being perpetrated from the same organisation’s lean policy. So whatpossible benefits does enforcing the regimes of the lean and quality philosophies upon themeasurement process have and how does this ultimately enhance the process improvementactivity? The key fundamental to embed with any process improvement is the removal ofwaste. The process improvement techniques embedded within lean and quality concepts areextremely powerful practices in the drive to eradicate waste but there are numerouscontextual problems with the application of the process improvement activity and itsassociated measurement system. The application demands of the organisation may bedependent on a number of financial and resource constraints which may introduce reasonsnot to apply stringent measurement methodology and practice. The failure of variousprocess improvement activities due to poorly managed measurement activity has arguablynever been comprehensively analysed. Process improvement activity theory fully embellishesthe need for applied robust measurement systems, so how can process improvement andmeasurement be systematically aligned to gain benefits? The aim of this paper is toconsider whether lean philosophies can be integrated and applied within measurementsystems. The discussion seeks to identify if seven Muda exist within measurement systemsand whether in doing so this will lead to benefits for process improvement activities.

In the manufacturing industry, many product characteristics are of one-sided tolerances. The process capability indices Cpu (u, v) and Cpl (u, v) can be used to measure process performance. Most research work related to capability indices assumes no gauge measurement errors. This assumption insufficiently reflects real situations even when advanced measuring instruments are used. In this paper we show that using a critical value without taking into account these errors, severely underestimates the α-risk which causes a less accurate testing capacity. In order to improve the results we suggest the use of an adjusted critical value, and we give a Maple program to get it. An example in a polymer granulates manufactory is presented to illustrate this approach.

Two new miniature metallic sealed-cells containing the triple point of water, WTP (273.16K) and the triple point of mercury, HgTP (234.3156 K) have been constructed for therealization of the International Temperature Scale of 1990 (ITS-90) at the NationalInstitute of Standards (NIS-Egypt). The new cells will provide facilities for thecalibration of Capsule-type Standard Platinum Resistance Thermometers (CSPRTs). The twocells will complete a multi-cells compartment in order to calibrate CSPRTs in one singleexperiment. The multi-cells compartment contains two other cells; the triple point ofargon (83.8058 K) and the triple point of oxygen (54.3584 K) that has been alreadydeveloped and characterized before [M.G. Ahmed, Y. Hermier, Development of an adiabaticcalorimeter in the range 54 K–273 K in frame of a scientific collaboration LNE-NIS, AIPConf. Proc. 1552, 153 (2013)]. The system can calibrate two CSPRTs at once.The compartment is accommodated in an adiabatic calorimeter. With a special technique, thecalorimeter could go down to a temperature of 52 K using liquid nitrogen and specialpumping system.

Manufacturing of high-quality components and assemblies is clearly recognised byindustrialised nations as an important means of wealth generation. A “right first time”paradigm to producing finished components is the desirable goal to maximise economicbenefits and reduce environmental impact. Such an ambition is only achievable through anaccurate model of the machinery used to shape the finished article. In the first analysis,computer aided design (CAD) and computer aided manufacturing (CAM) can be used to producean instruction list of three-dimensional coordinates and intervening tool paths totranslate the intent of a design engineer into an unambiguous set of commands for amanufacturing machine. However, in order for the resultant manufacturing program toproduce the desired output within the specified tolerance, the model of the machine has tobe sufficiently accurate. In this paper, the spatial and temporal sources of error andvarious contemporary means of modelling are discussed. Limitations and assumptions in themodels are highlighted and an estimate of their impact is made. Measurement of machinetools plays a vital role in establishing the accuracy of a particular machine andcalibrating its unique model, but is an often misunderstood and misapplied discipline.Typically, the individual errors of the machine will be quantified at a given moment intime, but without sufficient consideration either for the uncertainty of individualmeasurements or a full appreciation of the complex interaction between each independentlymeasured error. This paper draws on the concept of a “conformance zone”, as specified inthe ISO 230:1 – 2012, to emphasise the need for a fuller understanding of the complexuncertainty of measurement model for a machine tool. Work towards closing the gap in thisunderstanding is described and limitations are noted.

The Guide to the expression of uncertainty in measurement (GUM) requires, “that the results of a measurement have been corrected for all recognised significant systematic effects and that every effort has been made to identify such effects”, before the issue of evaluating their uncertainty is tackled. In addition, the GUM also requires that a model is used, expressing the functional dependence of the measurand on identified input quantities. The paper discusses the inter-relations between the so-defined two sets of influence quantities and proposes to unify their treatment.

The optical frequency comb generator (OFCG) is an attractive optical reference source forvarious applications such as optical frequency metrology, precision spectroscopy andtelecommunications [D.J. Jones, S.A. Diddams, J.K. Ranka, A. Stentz, R.S. Windeler, S.T.Cundiff, Science 288, 635–639 (2000); T. Udem, R. Holzwarth, T.W. Hänsch,Nature 416, 233–237 (2002); T.W. Hänsch, J. Alnis, P. Fendel, M. Fischer, C.Gohle, M. Herrmann, R. Holzwarth, N. Kolachevsky, Th. Udem, M. Zimmermann, Philos. Trans.R. Soc. A 363, 2155–2163 (2005)]. In particular, the OFCG can be used assource for absolute frequency measurement, providing a precise ruler for length metrology.In the present work we describe the results of absolute frequency measurements of primarywavelength standards at 633 nm on the sixth components, d, e, f, g, h and i of the R(127)11-5 hyperfine transition of the 127I2 molecule, at the SpanishCentre of Metrology, CEM. The values obtained with a femtosecond frequency comb (FC1500,Menlo Systems) at CEM are compared with the values recommended by the ConsultativeCommittee for Length (CCL) [T.J. Quinn, Metrologia 40, 103–133 (2003)]. Thisdetermination was made by beat frequency method between a femtosecond laser comb and aniodine-stabilized He-Ne laser. The difference between the mean frequency of the sixthcomponents of the standard laser and those of CCL recommended values for the samecomponents was found to be 6.557 kHz.

Quality of transformer oil plays vital role in the performance of transformer in electrical appliances. Measurement uncertainty is a general concept associated with any measurement and can be used in professional decision processes as well as judging attributes in many domains, both theoretical and experimental. As the tolerances applied in industrial production become more demanding, the role of measurement uncertainty becomes more important when assessing conformity to these tolerances. Measurement uncertainty plays a central role in quality assessment and quality standards. In an effort to meet national, international and commercial accreditation requirements, users of transformer oil testing machines must establish adequate methods of determining calibration and test measurement uncertainties. Determining measurement uncertainty for transformer oil testing equipments and test data can be a very complex process. Many factors affect the uncertainty of test data produced by testing machines. In this paper, the concepts associated with the procedure for estimation of uncertainty is discussed and the application of these for the determination of uncertainty in transformer oil testing equipments in government testing labs is illustrated. The objective of this study is to develop a methodology for determining the result of measurement concerning electrical properties of transformer oil and their respective uncertainties.

The advent of charge-coupled devices (CCD) has significantly extended the horizons offull-field measurement methods in many fields of fundamental and applied sciences,including fluid flow dynamics. One of the major applications of imaging sensors in fluidmechanics is the Digital Particle Image Velocimetry (DPIV), which is a non-invasive, fullfield optical measuring technique. Due to recent advances in image processing methods, andin digital imaging, laser and optics DPIV has become a dominant tool for obtainingvelocity information about fluid motion. On the other hand, over the last years,developments in micro- and nanofluidic systems have promised a shrinking of thedesktop-sized chemical and biological devices to microscale size, so a detailedinvestigation of the behaviour of flow inside these microdevices is essential for theoptimum design of microsystems, as well as for an understanding of flow dynamics in micronscales. In this work, the advances in visualization and quantitative measurements of flowvelocity measurements are reviewed and explained.

Currently, most advances in dimensional metrology might be seen by the evolution of non-contact measurement (optical measurements), in order to provide traceability for different areas that needs to calibrate microscopes or optical measure machines. In a similar way, the use of image processing techniques for the measuring of objects has been the subject of recent studies in computer vision and image metrology. In the attempt to meet the requirements and demands for high accuracy dimensional metrology with image processing techniques, this work will present the application of the image registration technique for the measurement of line scales. In the conventional calibration, the scales are measured in pre-established points, generally in intervals of 10% of the total scale length. With this application, it becomes possible to provide results for all the scale marks quickly and automatically, whereas in the conventional method it would require more time and, thus, a higher cost for the fulfillment of this measurement.

In order to determine mechanical properties of materials various kind of tests can be applied by means of using their tensile strength, lower yield stress, proof stress, impact strength, Brinell, Rockwell and surface hardness, elongation after fracture properties. Among these tests, three point flexural testing method has some advantages such as easy preparation (production) of samples and no gripping problems comparing to tension test. Flexural tests results should be obtained accurately to provide expected testing performance. The measurement uncertainty of flexural tests should be calculated by conducting all effective uncertainty parameters during the test procedure. In this study, the measurement uncertainty of the flexural test of ABS (Acrylonitrile Butadiene Styrene) material was investigated, which is widely used as industrial plastic material in many applications.

This article presents the development of a system used by the Brazilian Network of LegalMetrology and Quality – INMETRO and its delegated public bodies to increase the coverageof mandatory periodic verification on measuring instruments in Brazil, especially nonautomatic weighing instruments. Based on a governmental database of active establishmentsthat allowed the choice of an specific economic activity, the system provides a list ofestablishments where measuring instruments are used to commercial transitions and,therefore, subject to periodic mandatory verification. As a result, the use of systemincreased the number of measuring instruments controlled in Brazil, revealed areas forimprovement and provided references to set goals.