A new formulation of the density of air-saturated water as a function of temperature on the 1990 International Temperature Scale (ITS-90) is presented. Also, a new equation for calculating isothermal compressibility as a function of temperature on ITS-90 was developed. The equations are to be used to calculate the density of water, in the temperature range 5 to 40 °C on ITS-90, used in the gravimetric determination of the volume of volumetric standards.
Quality Assurance of the Measurement Process Quality Assurance of the Measurement Process means establishing, documenting, implementing, and maintaining a quality system appropriate to the laboratory's scope of activities. Having such a system in place will allow the laboratory to know, within the limits of a measurement process, that a measurement is valid with respect to its traceability, accuracy, and precision. December 2003 GLP 4 Good Laboratory Practice for Periodic Recalibration of State Standards A number of States have provisions in their weights and measures laws that require the periodic submission of their State standards to NIST for calibration. Those provisions are based on an early version of the Model Law (1911), which was considered appropriate for the circumstances that prevailed prior to the establishment of the New State Standards Program by NIST. Periodic calibration is necessary on a regular, periodic basis, and also when measurement control results from internal control charts or external round robins indicate questionable data. Standards of mass, volume, and length, fabricated from modem materials, kept in the controlled environment of a State metrology laboratory under the custody of trained metrologists, are generally stable and not subject to change. Moreover, the cooperative NIST-State audit programs often identify changes in ample time for corrective action in the unlikely event that such a change should occur. These same programs provide the necessary evidence of the ability March 2003 4. When two or more figures are to the right of the last figure to be retained, consider them as a group in rounding decisions. Thus, in 2.4(501), the group (501) is considered to be greater than 5 while for 2.5(499), (499) is considered to be less than 5. Several examples to illustrate the proper method of reporting corrections and uncertainties follow. Example 1 Suppose the correction for a weight is computed to be 1.3578 mg and the uncertainty is 0.5775 mg. First, round the uncertainty to two significant figures, that is, 0.58 mg. Then state the correction as 1.36 mg. Notice that the uncertainty and the correction express the same number of decimal places. Report the correction as 1 .36 mg ± 0.58 mg. Example 2 The volume of a given flask is computed to be 2000.714431 mL and the uncertainty is 0.084024 mL. First, round the uncertainty to two significant figures, that is, 0.084 mL. (Do not count the first zero after the decimal point.) Round the calculated volume to the same number of decimal places as the uncertainty statement, that is, 2000.714 mL. Report the volume as 2000.714 mL ± 0.084 mL. Example 3 The correction for a weight is computed to be 4.3415 mg and the uncertainty is 2.0478 mg. First, round the uncertainty to two significant figures, that is, 2.0 mg. (Notice that two significant figures are shown. The zero is a significant figure since it follows a non-zero number.) Then, round the correction to the same number of decimal places as the uncertainty statement, that is, 4.3 mg. Report the ...
Many of these procedures are updates to procedures that were originally published in NBS Handbook 145, Handbook for the Quality Assurance of Metrological Measurements, in 1986, by Henry V. Oppermann and John K. Taylor. The 2003 updates incorporated many of the requirements noted for procedures in ISO Guide 25, ANSI/NCSL Z 540-1-1994, and ISO/IEC 17025 laboratory quality systems. The major changes incorporated 1) uncertainty analyses that comply with current international methods and 2) measurement assurance techniques using check standards. No substantive changes were made to core measurement processes or equations, with the exception of SOP 2, Standard Operating Procedure for Applying Air Buoyancy Corrections. Procedures were updated in 2003 in conjunction with Jose A. Torres-Ferrer.
Measurement scientists work in calibration laboratories throughout the world. Yet, there are few university level courses available that cover the critical topics needed for performing and analyzing precision measurements-at the desired level. Many continuing education courses of this nature are taught by National Metrology Institutes (NMIs) and original equipment manufacturers (OEMs) of precision measuring equipment and measurement standards. What often happens in the measurement community is that subject matter experts and scientists who best know about measurements are asked to teach courses and tutorials, but most do not have a background in educational models or adult education principles. Over the past 3 years, the National Institute of Standards and Technology (NIST) Office of Weights and Measures (OWM)-has been providing train the trainer and adult education courses and opportunities to our subject matter experts to help them better analyze, design, develop, implement, and evaluate our technical training content. The goal has been to enable students to achieve a higher level of cognition on the Bloom's Taxonomy scale (e.g., application versus knowledge). Highlights of the key resources that have been incorporated into the instructional design process are presented as potentially useful for the professional development of instructors this is particularly useful for instructors without a background in educational theories and models. Some highlights of instructional design concepts are covered in one section to provide value added for those who do not have formal training or education in educational concepts. This paper also provides case study examples focused on laboratory metrology. The case study design integrates learning objectives, activities, assessment methods, and adult learning to create effective project based learning activities and a case study in a Fundamentals of Metrology course. The activities and examples used in the course and shared in this paper illustrate some of the essential knowledge and skills needed by measurement professionals and those engineers who interact with calibration staff to better perform and/or analyze precision measurements. These examples, and portions of the case study, have been implemented in a training laboratory, as well as in non-laboratory conference center classrooms, and could easily be implemented with varying and limited resources in engineering courses. Course Description and Background The Fundamentals of Metrology course is a 40-hour, team and project based course. It includes approximately 60 percent of the time spent in activities related to the main case study. Appendix A includes a table that shows the course topics and key knowledge, skills, and acronyms that are covered and provide a foundation of knowledge needed for more specific courses that are taught on various measurement parameters (e.g., mass, volume, thermometry, forensics, etcetera). As
industry in the development of technology . . . needed to improve product quality, to modernize manufacturing processes, to ensure product reliability . . . and to facilitate rapid commercialization ... of products based on new scientific discoveries." NIST, originally founded as the National Bureau of Standards in 1901, works to strengthen U.S. industry's competitiveness; advance science and engineering; and improve public health, safety, and the environment. One of the agency's basic functions is to develop, maintain, and retain custody of the national standards of measurement, and provide the means and methods for comparing standards used in science, engineering, manufacturing, commerce, industry, and education with the standards adopted or recognized by the Federal Government.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.