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A Study of Factors that Influence Micropipette Calibrations
Elsa Batista , Eduarda Filipe, Nelson Almeida
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721717
Publisher NCSL International | Published 3/1/2015 | Pages 50-58
Abstract: The gravimetric method is normally used in the calibration of micropipettes, based on ISO 8655 and ISO 4787. In order to verify the influence of specific experimental details of the normalized procedure described in ISO 8655-6
(and others not described in the standard) on the delivered volume of a micropipette, several experimental tests were performed by the Volume Laboratory (LVO) of The Portuguese Institute of Quality (IPQ). These tests include the angle variation of
aspiration and delivery of liquid, the immersion depth of the tip, aspiration and delivery time, the type of tip and altitude. The results verified that the amount of liquid delivered from a micropipette depends on very specific conditions. Some of
the more relevant conclusions of this experimental study were that the delivered volume can be lower than expected if the delivery angle is larger than 60° and also if the laboratory is working at high altitudes. Higher than expected volumes can be
delivered if the micropipette is immersed too deeply (more than 3 mm) into the liquid and the aspiration time is too long (> 8 s).
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721713
Publisher NCSL International | Published 3/1/2015 | Pages 26-31
Abstract: A calibration system for optical fiber laser sources has been developed at the Government of the Hong Kong Special Administrative Region Standards and Calibration Laboratory (SCL). The measurements of wavelength, output power
level and output power stability of optical fiber laser sources fitted with fiber channel/angled physical contact (FC/APC) connectors are detailed. The wavelength is directly measured by the laboratory wavelength meter. The standard measurement uncertainty
obtainable by this calibration method is less than 1 picometer (pm). The output power is the summation of the measured power by the laboratory's electrically calibrated pyroelectric radiometer (ECPR), and the insertion loss between the source and
the ECPR with a standard measurement uncertainty of about 3.7 %. The output power stability is evaluated by measuring the maximum and minimum fluctuation of the measured optical power using the laboratory ECPR which has three significant digits of
resolution.
Determination of Emissivity by Use of Reflected Thermal Radiation
Frank Liebmann
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721714
Publisher NCSL International | Published 3/1/2015 | Pages 32-37
Abstract: The determination of emissivity is crucial in any temperature measurement using radiation thermometry. Without this knowledge, large measurement uncertainties result. There is a lack of information on emissivity for common materials.
When databases are available, they often give emissivity for a specific material in a range or give emissivity for different conditionings of the material. This information may not apply to certain uses of the material, creating considerable doubt
for anyone making measurements in the field. Therefore, a method to determine emissivity for a material object in the field is needed. In 2011, Yamada and Ishii discussed a method that was set up in a fixed geometry to determine the emissivity of
a specular object. In this paper, a method is discussed to determine the emissivity of both specular and diffuse objects using a thermal radiation source. The paper presents the theory plus assumptions that were made. It then discusses practical measurements
that were made to verify these assumptions. These measurements are then compared to emissivity determined by other methods.
Establishing a Traceability Chain for Sound Pressure and Vibration Amplitude Measurements
Naveen Garg
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721718
Publisher NCSL International | Published 3/1/2015 | Pages 60-66
Abstract: This paper discusses the establishment and assessment of metrological traceability, including the provision of metrological references by a metrological institutional framework and the role of inter-laboratory comparisons, in
the realization of the units of sound pressure level and vibration amplitude. The paper discusses the national primary and secondary standards maintained at CSIR-NPL, India for acoustic and vibration metrology; the validation of the Calibration and
Measurement capabilities (CMCs) through participation in key comparisons with other national metrology institutes, and the establishment of traceability chain for government and industrial laboratories located throughout India. The work presented
here describes how the measurement uncertainty of the primary and secondary standards has been reduced. It also describes a measurement chain that disseminates the units of sound pressure and vibration from the national level to industry with only
a small degradation in measurement uncertainty.
Estimating Thermal Effects for Granite Surface Plate Calibration
Gordon A. Skattum
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721716
Publisher NCSL International | Published 3/1/2015 | Pages 50-58
Abstract: This paper explores the sources of variation and thermal effects applied to granite surface plate calibration, and their impacts on the quality, uncertainty, and appropriate decisions about when to resurface. It will also address
ASME B89.3.7-2013 and provide an approach for estimating uncertainty components due to the temperature related sources. The components, especially temperature stability, are always present and can significantly affect or dominate measurement uncertainty
in the calibration of overall flatness. Examples will demonstrate that thermal effects should be included in any uncertainty analysis for the calibration of overall flatness. An important and ongoing effort related to this paper is to research, identify
and document current industry practices and provide guidelines for the “best practice” calibration of granite surface plates.
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721715
Publisher NCSL International | Published 3/1/2015 | Pages 38-48
Abstract: This paper discusses an approach for evaluating the accuracy of dense 3D surface reconstruction techniques based on images. So far, the emergence of these novel techniques has not been supported by the definition of an internationally
recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in image-based 3D modeling, we present an approach for the assessment of
the metric performance of an open-source set of routines for bundle block adjustment and dense image matching (Apero/MicMac). The evaluation is performed using a metrological approach, through comparisons between image-based 3D generated data and
‘reference’ data acquired with two hemispherical laser scanners, one total station, and one laser tracker. Aspects of traceability and measurement uncertainty of all these reference 3D data are discussed. The methodology is applied to two case studies,
tailored to analyze the software capabilities in dealing with both outdoor and environmentally controlled conditions. Comparative data and accuracy evidence provided by both tests allow the study of some key factors affecting 3D model accuracy.
Metrology Survey Applied in Health Care Facilities: Evaluation and Outcome Analysis
Maria do Cue Ferreira, Ana Sofia Matos
NCSLI Measure | Vol. 10 No. 1 (2015) | 10.1080/19315775.2015.11721712
Publisher NCSL International | Published 3/1/2015 | Pages 22-25
Abstract: To evaluate the role of metrology in health care facilities, we conducted a study to identify and analyze issues that arise when the concept of metrological traceability is applied to hospital facilities. Survey data were collected
from 44 Portuguese hospitals. The results allowed us to identify some key metrological indicators that pertain to hospitals, and to conclude that metrological traceability is absent from the daily considerations of health care professionals and facilities.
An Analysis of ISO/IEC 17025 Nonconformities Reported for Audits in Brazil
Filipe Medeiros Albano, Morgana Pizzolato , Francine de Brito Nagel
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721727
Publisher NCSL International | Published 6/1/2015 | Pages 66-74
Abstract: This paper presents an analysis of nonconformities found when auditing testing and calibration laboratories in accordance with ISO/IEC 17025. The auditing was conducted by auditors from Rede Metrologica RS (RMRS), a nonprofit
technical association in Brazil. The objective of this study was to identify the ISO/IEC 17025 requirements that have the highest number of non-conformities. We collected data from about 500 laboratory audits performed during the five-year period
from 2008-2012. Data were analyzed by grouping the laboratories by calibration and test area, by ISO/IEC 17025 requirements, and by year. The calibration areas were: acoustic, length, electricity, force, torque and hardness, mass, optical, pressure,
flow and level, temperature and humidity, time and frequency, viscosity, and volume. The testing areas were: chemistry and physical chemistry, microbiological, biological and toxicological, mechanical, and biochemistry. We considered separately the
percentages of nonconformities in technical and management requirements. We also present data showing the trend of nonconformities obtained during five years of assessments.
Application of Cost Effective Enclosures to Reduce Environmental Influences in Dimensional Measurements
Pieter Greeff
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721725
Publisher NCSL International | Published 6/1/2015 | Pages 54-61
Abstract: Length measurements are always affected by environmental conditions, of which temperature is typically a major concern. This concern can be addressed by applying error correction, uncertainty estimation, or environmental control.
Control can be achieved by controlling the whole laboratory, but this can be expensive. Custom built enclosures around individual instruments, however, offers a cost effective alternative. Two different dimensional measurements (roundness and gauge
blocks by interferometry) are used as examples to investigate this in a practical sense, since both are significantly influenced by the environment. This paper will focus specifically on the deviation from the reference temperature and environmental
stability. The results obtained by subsequent implementation of control and isolation enclosures will be presented. Here a prototype gauge block temperature control chamber design reduced the temperature range of the measurement volume from ±1 °C
to ±0.1 °C, while the introduction of a roundness enclosure reduced probe drift by 96 %.
Color Mark Sensor Calibration System for Timing Devices with a Seven-Segment LCD
Ahmad Sahar Omar, Mohd Fauzi Othman, Erik F. Dierikx, Mohd Nasir Zainal Abidin
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721728
Publisher NCSL International | Published 6/1/2015 | Pages 76-83
Abstract: A patent pending calibration system for timing devices with a seven-segment liquid crystal display (LCD) is presented in this paper. The prototype calibration system uses a color mark sensor, a gate controller, a toggle switch,
and dual counters. It operates by directing the light spot of the color mark sensor onto an identified segment of the seven-segment LCD. When the device under test is running, the signal output from the color mark sensor, depending on the state of
the chosen segment, will trigger the toggle switch to start or stop the counters to count the pulses of the 1 kHz reference frequency. By means of the toggle switch, the first counter will stop counting when the second counter starts counting, and
vice versa, without halting the counting processes; thus, eliminating the elapsed time between the measurement readouts reported by the dual counters. The experimental results and bilateral comparisons showed that the new calibration system based
on this technique has a measurement uncertainty of 6.8 × 10−8.
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721726
Publisher NCSL International | Published 6/1/2015 | Pages 62-65
Abstract: This paper presents a new test apparatus for the evaluation of the humidification efficiency of heat and moisture exchangers (HMEs). These devices are widely used in invasive ventilation conditions to humidify and to heat medical
gases inhaled by the patients. The new custom-made test apparatus allows simultaneous measurements with the two most common methods for in vitro tests: gravimetric, which is considered the reference method by the international standard ISO 9360, and
hygrometric. In the reference method, the absolute humidity of the inhaled gas (HME moisture output) is determined by subtracting, from the absolute humidity of the exhaled gas (AHexh), the moisture loss measured with a precision balance. Consequently,
AHexh is supposed to be stable throughout the test. In addition, ISO 9360 does not set a limit for the maximum value of AHexh in the measuring process. In the new experimental test apparatus, AHexh is constantly monitored and the humidification efficiency
of an HME is expressed as the ratio of the HME moisture output with respect to AHexh, the so-called relative efficiency. Results show that average values of AHexh and of the relative efficiency are very similar with both methods, confirming the reliability
of the new test apparatus.
Fiber Bragg Gratings Embedded in 3D-Printed Scaffolds
Gregory Strouse, Zeeshan Ahmed , Khazar Choudhry, Peter C. Liacouras, Gerald T. Grant
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721724
Publisher NCSL International | Published 6/1/2015 | Pages 50-52
Abstract: In recent years there has been considerable interest in utilizing embedded fiber optic based sensors for fabricating smart materials. One of the primary motivations is to provide real-time information on the structural integrity
of the material so as to enable proactive actions that prevent catastrophic failure. In this preliminary study we have examined the impact of embedding on the temperature-dependent response of fiber Bragg gratings (FBG). Our results indicate that
scaffold strain has a significant impact on the embedded sensor's temperature response. Thus, the use of embedded sensors will require the development of in corpus techniques that can calibrate sensors while they are embedded.
Laboratory Activities for a Dimensional Metrology Class
Joseph P. Fuehne
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721723
Publisher NCSL International | Published 6/1/2015 | Pages 42-48
Abstract: The Purdue College of Technology in Columbus, Indiana recently offered, for the first time, a class in Dimensional Metrology. In keeping with its hands-on, project-based learning philosophy, the class mixes many laboratory activities
with the lecture component of the class. The laboratory activities focus on accomplishing some engineering function that requires measurement. These activities are not just a matter of measuring a few items with the supplied tools; there is always
a clear engineering or manufacturing objective with each laboratory activity. In some cases, this may also include a reverse-engineering project that incorporates a measure-manufacture-measure iterative cycle to determine the effectiveness of the
manufacturing operation. This paper discusses in detail the experiments utilized in the class. Some examples include gage R&R studies, a calibration exercise, determining constants of springs, measuring threads, and measuring gears. The activities
are based on the premise that adding realistic and engaging measurement activities to a class better prepares students for careers in product design and manufacturing.
The Redefinition of the SI: Impact on Calibration Services at NIST
Michael R. Moldover, Neil M. Zimmerman , Gregory Strouse, David B. Newell , Jon Pratt
NCSLI Measure | Vol. 10 No. 2 (2015) | 10.1080/19315775.2015.11721722
Publisher NCSL International | Published 6/1/2015 | Pages 36-41
Abstract: As most readers are probably at least vaguely aware, it is likely that the SI system of units will be redefined in 2018. This redefinition would fundamentally change the logical structure of the SI, with one result being a substantial
change in how mass is realized and disseminated within national metrology institutes (NMI's) such as the National Institute of Standards and Technology (NIST). However, we expect that the only impact on how customers see calibration services will
be small step changes that NIST will document and publicize to customers in advance. In this article, we list the main areas of calibration services at NIST, describe how for most of them there will be negligible impact, discuss the impact on mass
and DC electrical calibrations, and explain our best predictions as to how we expect NIST to make a seamless transition for customers in those two areas.
Calibration of Weighing Instruments: Measurement Uncertainty, Minimum Weight and the Safe Weighing Range
Ian Ciesniewski, Klaus Fritsch
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721736
Publisher NCSL International | Published 9/1/2015 | Pages 56-65
Abstract: The calibration of non-automatic weighing instruments (NAWIs) is one of the key activities in quality control and in the production area that needs to be carried out rigorously in order to accomplish pre-defined quality attributes
of a weighing process. Many misconceptions and ambiguities with regards to efficient calibration of balances and scales have been prevalent in the industry for many decades. There are recent activities in the scientific community to address this issue
by creating a harmonized approach for calibration of NAWIs that is based on an internationally recognized calibration guideline. This approach goes beyond traditional calibration as it addresses not only the performance of the instrument at calibration,
but also provides guidance to estimate the uncertainty during day-to-day use. This approach has significant practical importance as it facilitates the assessment of the equipment's performance against user specific weighing tolerance requirements.
One of the most important implications is the definition of the so-called minimum weight and the safe weighing range, which is derived from the uncertainty in use. Weighing quantities in the safe range of the instrument ensures adherence to user-specific
weighing tolerance requirements, and thus fosters compliance with the pre-defined quality attributes of a weighing process.
Measured Ionospheric Delay Corrections for Code-based GPS Time Transfer
Victor Zhang , Zhiqi Li
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721737
Publisher NCSL International | Published 9/1/2015 | Pages 66-71
Abstract: In Global Positioning System (GPS) time transfer measurements, all of the delays in receiving GPS timing signals, including the ionospheric delay in the signal path and the internal delay of a GPS receiver (receiver delay),
must either be corrected for or included in the uncertainty analysis. For code-based GPS time transfer with single frequency receivers, the ionospheric delay can be corrected using the Klobuchar model, or using the IGS ionospheric maps. The modeled
ionospheric delay correction is most effective during the nighttime hours. The IGS ionospheric map corrections have much smaller uncertainties than corrections from the Klobuchar model, especially during the daytime hours, but the effects of ionosphere
variations are still noticeable in the received GPS signals due to the resolution of the map. With the use of dual-frequency multi-channel GPS receivers, the ionospheric delay can be obtained from the receiver's dual-frequency measurements. The measured
ionospheric delay correction removes nearly all of the ionospheric delays from the GPS time measurements. However, the receiver delay for the measurements on both the L1 and L2 frequencies are used in computing the ionospheric delay, and if the receiver
delay is not calibrated or if the delay has changed, the error in receiver delay can propagate to the measured ionospheric delay corrections, and add uncertainty to the time transfer results. Thus, to achieve the lowest possible time transfer uncertainty,
it is important to locally monitor receiver delay changes and to periodically calibrate the receiver delay.
New Techniques and Methods for Managing Measurement Risk
Teruhisa Tsuru
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721738
Publisher NCSL International | Published 9/1/2015 | Pages 72-75
Abstract: Murata Manufacturing Co., Ltd. produces many kinds of electronic products in very large quantities, and utilizes management techniques and methods for the measurement of risk in the inspection process to guarantee the quality
of these products. The AQL (Acceptable Quality Level) technique was used in production as a general sampling technique in production, but this method could not guarantee consumer's risk in the lot. The LTPD (Lot Tolerance Percent Defective) improves
upon AQL by guaranteeing consumer's risk in the lot. However, LTPD requires a sample size more than 10 times larger than AQL. To solve this problem, we have developed a new sampling technique and method that allows a decrease in the number of required
samples. It also allows us to reduce the probability, in which the consumer's risk of the lot is greater than the designated consumer's risk, to less than 37.5 parts per million (ppm). This paper explains the new risk calculation and sampling techniques
in detail.
Optimizing Data Logger Setup and Use for Refrigerated Vaccine Temperature Monitoring
Wyatt W. Miller, Gregory Strouse, Michal J. Chojnacky , L.F. Chaves Santacruz
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721733
Publisher NCSL International | Published 9/1/2015 | Pages 28-37
Abstract: Accidental freezing of refrigerated vaccine represents a significant public and private healthcare cost. Freeze-damaged vaccines lose their effectiveness, putting public health at risk. U.S. immunization programs have strengthened
vaccine storage and handling recommendations to mitigate this danger. However, current publications describing the setup and configuration of vaccine temperature monitoring devices allow for a range of untested interpretations. In this paper, we report
on our study of specific temperature monitoring setup variables, including vial size, thermal buffer type, buffer fluid concentration, and placement of the probe-in-vial setup, in an effort to provide definitive guidance on the selection of an optimal
temperature monitoring setup and methodology for use in vaccine storage refrigerators.
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721735
Publisher NCSL International | Published 9/1/2015 | Pages 44-54
Abstract: ANSI/NCSLIZ540.3 redefined the “test uncertainty ratio” (TUR) measurement quality metric as a ratio of maximum permissible error to measurement process uncertainty. The definition engendered some immediate and lingering disagreement.
Much of this disagreement stems from inconvenience, because including uncertainty components from the unit under test (UUT) may cloud conformity assessments when an instrument's maximum permissible error (MPE) specification falls near its repeatability
or resolution limits. The TUR then apparently loses its value as a simple measurement process validation. Some practitioners view UUT error contributions as a simple reality to address in calibration processes, others consider such inclusions, at
least in some circumstances, a logical fallacy. Unfortunately, differing opinions also arise between laboratory assessors and, by implication, between accreditation bodies. This paper neutrally reviews the problem from first principles and evaluates
the two positions in terms of metrological compatibility and measurement decision risk. The paper also discusses mitigation methods.
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721732
Publisher NCSL International | Published 9/1/2015 | Pages 20-27
Abstract: The NIST Uncertainty Machine (http://uncertainty.nist.gov) is a web-based software application produced by the National Institute of Standards and Technology (NIST) to evaluate the measurement uncertainty associated with a scalar
output quantity that is a known and explicit function of a set of input quantities for which estimates and evaluations of measurement uncertainty are available. Input and output quantities are modeled as random variables and their probability distributions
are used to characterize measurement uncertainty. The NIST Uncertainty Machine implements the approximate method of uncertainty evaluation described in the “Guide to the expression of uncertainty in measurement” (GUM), and the Monte Carlo method of
the GUM Supplement 1 (GUM-S1). The NIST Uncertainty Machine is freely accessible worldwide from any computer connected to the World Wide Web. Using a Web browser, the user specifies all the necessary information in an easy-to-use form. The calculations
are performed on a NIST server, which returns the results to the user by posting them on a Web page that is displayed in the user's browser, and by writing them to files that the user may download. The NIST Uncertainty Machine also produces a conventional
uncertainty budget that lists the contributions that the uncertainties associated with the input quantities make to the uncertainty associated with the output quantity. We show how these contributions can be derived from the Monte Carlo samples, and
in the process illustrate an interesting and informative fact that conventional uncertainty budgets ignore.
Thomas Lipe, Charles J. Burroughs, Samuel P. Benz, Joseph Kinard, Paul D. Dresselhaus , Yi-Hua Tang
NCSLI Measure | Vol. 10 No. 3 (2015) | 10.1080/19315775.2015.11721734
Publisher NCSL International | Published 9/1/2015 | Pages 38-42
Abstract: We report on the use of a quantum-based AC voltage standard for ac-dc difference metrology at the National Institute of Standards and Technology (NIST). The paper describes the characterization of the output transmission line
and the methods used to correct for its errors, the use of the quantum standard in voltage scaling to calibration thermal transfer standards, and its use in the NIST calibration services for thermal voltage converters at frequencies up to 100 kHz.
Plans for future use are also presented.
Calibration of Defibrillator Analyzers
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721747
Publisher NCSL International | Published 12/1/2015 | Pages 50-55
Abstract: The Standards and Calibration Laboratory (SCL) in Hong Kong has set up a calibration facility for defibrillators and defibrillator analyzers. Defibrillators are medical devices designed to resume the normal heart pulse of a
patient by discharging energy pulses to a person who is suffering from an emergency cardiac attack. They are commonly used in hospitals and medical institutes. At the SCL, the energy delivered by a defibrillator is measured using a high quality digital
sampling system. The system includes a high voltage divider, a sampling voltmeter, an impedance analyzer, and a control computer. The sampled voltage waveform is digitally processed to derive the delivered energy. The system can also be used to check
the accuracy of a defibrillator analyzer. The sampling system and its signal processing are described in this paper. To ensure the accuracy of the sampling system, it is calibrated against the laboratory's voltage and time reference standards. A standard
waveform with calculable energy is used to verify the sampling system. It is shown that the system can achieve an energy measuring uncertainty of better than 0.7 %.
A New Test System for Measuring RF Sources and Receivers
Michael Dobbert
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721746
Publisher NCSL International | Published 12/1/2015 | Pages 44-49
Abstract: A new test system has been developed that uses a vector network analyzer (VNA) to make RF and microwave S-Parameter, power accuracy, power linearity, harmonic distortion, intermodulation distortion, phase noise, and frequency
accuracy measurements. The test system, which includes fixturing to allow connecting various devices under test (DUTs), has been deployed in a manufacturing test environment. Measurement uncertainties take into account the expected temperature range
of the manufacturing environment, the impact of the fixturing, and the expected uncertainties from the measuring equipment. The environmental and fixturing characterizations were determined by repeatedly calibrating the vector network analyzer under
various environmental conditions, and then analyzing the variability of the measured values when correcting for multiple calibrations. This paper discusses the test system design, the characterization of the fixturing, the effects of temperature,
and the validation of the calibration process. The paper also provides a detailed discussion of power accuracy measurements.
Eutectic Ga-In Melting-Point Blackbody for Radiation Thermometry
Daniel Cárdenas-García, Veronica Sastre-Muñoz
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721743
Publisher NCSL International | Published 12/1/2015 | Pages 24-27
Abstract: The Radiation Thermometry Group at the Centro Nacional de Metrología (CENAM) is presently working with low-temperature fixed-point blackbodies to study their suitability for calibration and verification of radiation thermometers.
The International Temperature Scale of 1990 specifies two fixed points in the 0 °C to 30 °C temperature range: the triple point of water and the melting point of gallium. We designed a eutectic Ga-In melting-point blackbody that could serve as a good
candidate as a third fixed-point in the middle of those fixed points. The measured radiance temperature of the eutectic Ga-In melting-point blackbody was 15.67 ± 0.10 °C (k = 1).
Zeeshan Ahmed , James Filla, William Guthrie, John Quintavalle
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721744
Publisher NCSL International | Published 12/1/2015 | Pages 28-31
Abstract: In recent years there has been considerable interest in developing photonic temperature sensors such as the Fiber Bragg gratings (FBG) as an alternative to resistance thermometry. In this study we examine the thermal response
of FBGs over the temperature range of 233 K to 393 K. We demonstrate, in a hermetically sealed dry Argon environment, that FBG devices show a quadratic dependence on temperature with expanded uncertainties (k = 2) of ≈500 mK. Our measurements indicate
that the combined measurement uncertainty is dominated by uncertainty in determining the peak center fitting and by thermal aging of polyimide coated fibers.
Summary of Outside Micrometer Calibration Proficiency Testing (PT2014-KA02) in Taiwan
Chen-Yun Hung, Paul Kam-Wa Lui, Yi-Ting Chen, Pin-Hao Wang
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721749
Publisher NCSL International | Published 12/1/2015 | Pages 64-70
Abstract: Proficiency testing is an established way to demonstrate a laboratory's measurement capabilities. Accredited laboratories are usually requested to participate in proficiency testing conducted by the laboratory accreditation
organizations in their countries. The Center for Measurement Standards / Industrial Technology Research Institute (CMS/ITRI) has long been committed to measurement technologies and statistical engineering in Taiwan and is one of the Proficiency Testing
Providers (PTPs), with an accreditation number of P002, accredited by Taiwan Accreditation Foundation (TAF). This paper summarizes the results of a 2014 outside micrometer calibration proficiency testing scheme, number PT2014-KA02, held in Taiwan.
Twenty-five TAF accredited calibration laboratories participated in the proficiency testing, and the |En| values of each participating laboratory are smaller than one. This implies that all the participants' results are satisfactory with respect to
each other and that the measurement capabilities of laboratories performing micrometer calibrations are very consistent in Taiwan.
The 2014 North American Josephson Voltage Interlaboratory Comparison
Jonathan Harben, Yi-Hua Tang, Harold Parks, James Wachter
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721748
Publisher NCSL International | Published 12/1/2015 | Pages 56-62
Abstract: The 10th North American Josephson voltage standard (JVS) interlaboratory comparison (ILC) at 10 V was completed in 2014. This ILC was unique because it consisted of two parts. An on-site comparison was conducted between the
National Institute of Standards and Technology (NIST) transportable JVS and the pivot laboratory's conventional JVS (CJVS) system. A set of four traveling Zener voltage standards then served to transfer traceability from the pivot laboratory to the
12 other participants. In addition to the regular ILC activities, a second on-site comparison was conducted between the NIST transportable JVS and the programmable JVS (PJVS) provided by the National Aeronautics and Space Administration (NASA). Due
to limited availability of the PJVS, only two laboratories were selected to make direct comparisons between their CJVS systems and NASA's PJVS. The method has been used for the first time in the JVS ILC and has the advantage of using the PJVS as a
transfer standard. This allowed the participating laboratory to make comparisons using its CJVS system against the 10 V PJVS in the same manner as the measurements for Zener standards are performed while overcoming limitations of the Zener noise.
Results of the 2014 ILC are provided in this paper.
Traceability Considerations for the Characterization and Use of Measuring Systems
Charles Ehrlich
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721745
Publisher NCSL International | Published 12/1/2015 | Pages 32-43
Abstract: There are several different ways that measuring systems (which include measuring instruments) can be characterized, including calibration, adjustment, and verification (or testing). Common elements of such characterizations
include comparisons of indicated values with values obtained when using measurement standards, specification of influence quantities and operating conditions, and statements of system resolution and repeatability. Differing elements of such characterizations
include whether or how measurement uncertainty is recorded during the characterization, whether any change is made to the measuring system (including in hardware and software) during the characterization process, and whether recording the measured
error of indication is part of the characterization process. The way that a measuring system is characterized will typically influence how measurement results are obtained and stated when subsequently using the measuring system to perform measurements.
Because a measurement result includes the measurement uncertainty as well as the measured value, the metrological traceability that is ascribed to measurement results obtained when using such characterized measuring systems can be impacted by the
type of characterization that was performed. When calibration, adjustment, or verification of a measuring system results in being able to obtain explicit measurement uncertainties when using the system, metrological traceability is ensured. However,
for some types of verification (or testing), such as when Test Accuracy Ratios (TARs) or Test Uncertainty Ratios (TURs) are used, the measurement result does not typically contain an explicit measurement uncertainty, which brings the metrological
traceability into question. This paper takes a preliminary look at how metrologically traceable measurement results, including associated uncertainties, might be obtained in this latter case.
Uncertainty Evaluation of the Calibration of Dial Indicator Calibrators by Laser Interferometer
Huang-Chi Huang, Wei-Cheng Chang, Huay-Chung Liou, Paul Kam-Wa Lui
NCSLI Measure | Vol. 10 No. 4 (2015) | 10.1080/19315775.2015.11721742
Publisher NCSL International | Published 12/1/2015 | Pages 20-23
Abstract: This paper describes the uncertainty evaluation procedure for a dial indicator calibrator calibration in accordance with the ISO/IEC Guide 98-3:2008. The effects of error sources on this calibration are analyzed to estimate
the corresponding standard uncertainties and sensitivity coefficients. The combined standard uncertainty and effective degrees of freedom are then calculated. The coverage factor can be found by taking the t-factor corresponding to the effective degrees
of freedom. Finally, the expanded uncertainty can be obtained by multiplying the coverage factor and the combined standard uncertainty. The calibration method of the dial indicator calibrator is also briefly described. For the calibration of a dial
indicator calibrator with a resolution of 0.1 μm in the measurement range of (0 to 60) mm, the expanded uncertainty is estimated to be 0.81 μm (k = 2.05, 95 % confidence level).
