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Research paper : Improvement of reliability in pressure measurements and international mutual recognition (T. Kobata et al.)−226−Synthesiology - English edition Vol.4 No.4 (2012) the cost of remote calibration is not sufficiently low compared to carry-in calibration. The main reason is because the cost of the multi-function, high-performance transfer device used for remote calibration is high. To diffuse remote calibration, it is necessary to decrease the cost of the transfer device by narrowing down the functions according to the required uncertainty.4 Region where the digital pressure gauge can be used as transfer deviceQuestion (Jun Hama)Please describe the specific work on the development of the simple, fast, and low cost method for calibration and standard provision for pressure using the digital pressure gauge, as much as you can disclose. Particularly, the advancement of remote calibration method at the industrial sites is an important key word. What is your assumed region of coverage in Japan and abroad? Are there some regions that are limited due to the uncertainty factors of the digital pressure gauge?Answer (Tokihiko Kobata)The specific developments were added in subchapter 6.3 for the remote calibration of pressure. I think it will become important to provide the realized values of the national standard for pressure widely and smoothly to the industrial sites. In the future, to further increase the reliability of pressure measurement, I think it is necessary to not only guarantee the results of calibration done at intervals but also to guarantee the reliability of the displayed values of the pressure gauge used in the industrial sites consecutively during regular use.For the region covered by remote calibration, basically if it is a place where the transfer device can be sent safely, installed stably, and where the information network such as the Internet can be used, I don’t think there is any particular limitation, regardless of whether it is in Japan or abroad. However, in regions that may require a long time to send the transfer device, quick calibration that is the merit of remote calibration may be lost. Also, as you indicated, since the digital pressure gauge is used as the transfer device in remote calibration, the uncertainty factors shown in chapter 5 must be considered according to the environment where the calibration is done. For example, if the air conditioning is not sufficient, the uncertainty of calibration may increase due to the changes in the surrounding temperature.5 Trends of foreign countries in using the digital pressure gaugeQuestion (Akira Ono)Is there a trend toward incorporation of high-precision digital pressure gauges as a transfer device in foreign countries as well? Or is it a trend only in Japan?Answer (Tokihiko Kobata)In this paper, the establishment and maintenance of the national standard for pressure, international comparison of the national standard, and the cases for incorporating the digital pressure gauge into the Japanese national standard were described. I shall explain the situations.First, on the use of digital pressure gauge in the comparative measurement of the pressure balance used for the establishment and maintenance of the national standard for pressure, the method of using the digital differential pressure gauge or the first calibration method described in subchapter 6.1 is used in other countries particularly for the calibration of gas pressure. However, the comparative method, the second calibration method, includes an elemental technology developed originally by AIST, and currently only AIST applies this method to the calibration in a wide range of pressure from low to 1 GPa. These two methods upgraded by AIST are recognized to conform sufficiently to the calibration results of the traditional methods, and are suitable for automation. In fact, they are being employed by Japanese calibration labs, and I believe it will eventually be used widely in other countries also.Next, the use of the digital pressure gauge in the international comparison of the national standards is expanding. Particularly, in the low-pressure range of 1 kPa or less that normally cannot be generated with a pressure balance, it is common practice to use multiple high-precision digital pressure gauges as the transfer device. Also, in the international comparison that involves transportation in vast areas such as the Asia Pacific, United States, or Africa, there is greater transportation merit in using the small and lightweight digital pressure gauge as the transfer device, rather than the large and heavy pressure balance, as mentioned in subchapter 6.2.For the remote calibration indicated as an example of incorporating the digital pressure gauge into the Japanese national standard, several similar technological developments have been reported around the world. However, currently, the remote calibration service for pressure gauge is established only at AIST. Several national metrology institutes around the world are interested in this remote calibration technology, and if the issues such as the reduction of calibration cost and the building of the framework for the calibration lab accreditation can be solved, as mentioned in subchapter 7.1, its use is expected to expand overseas as well as in Japan.6 Development of remote calibration technology for quantities other than pressureQuestion (Akira Ono)I think the description in this paper is an example where increased performance of the transfer device had a major effect on the entire standards system. Are there any examples for quantities other than pressure?Also, can you please briefly describe what approaches were taken for quantities other than pressure in the NEDO project for the remote calibration mentioned in subchapter 6.3?Answer (Tokihiko Kobata)Recently there have been various efforts to increase the performance of the transfer device (transfer standard) for various quantities, and the effect of the transfer device on the respective standard system is increasing. For quantities other than pressure, an example where the increased performance of the transfer device had great effect on the standard system is in the temperature measurement as described in Synthesiology [Vol. 3, No. 1, pp. 26-42 (Jul. 2010)]. In that paper, Arai et al. built the standard system for high temperature, and effectively utilized the newly developed thermocouple as the transfer device to maintain the reliability of the measurement.In NEDO’s e-trace Project, the development of the remote calibration technology was done to efficiently provide various measurement standards. The various measurement standards that were studied in the e-trace project can be roughly categorized into two groups. One is the standard for the remote calibration using the international positioning system (GPS) and the optical fiber network, and the other is the standard using the portable transfer device. The former includes the standards for time (frequency), length (wavelength and optical fiber application), and electricity (direct current voltage), while the latter includes the standards for electricity (AC voltage, low frequency impedance), radiation, three-dimensional coordinate measurement, vibration and acceleration, pressure, and temperature. In the time (frequency) standard that is a typical example of the former, the remote calibration technology for frequency was developed using the method mediated by the GPS satellite. For the latter, we developed the technology for conducting the remote calibration by sending the transfer device to the client-designated place and then using the Internet to do the calibration, in the same way as in the pressure standard described in subchapter 6.3.

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