A. Mariscotti, P. Pozzobon
PROCEDURE FOR THE MEASUREMENT OF THE ELECTRICAL PARAMETERS OF RAILWAY TRACTION LINES

Measurements of the electrical parameters of a traction line were performed over the 0-200 kHz frequency range on a line section purposely prepared at La Spezia (Italy). The electrical parameters are determined by an indirect approach: only the terminal variables (voltages and currents and hence impedance and admittance) may be measured and the per-unit-length electrical parameters are determined using a Multiconductor Transmission Line model of the test track section; the parameters of the model are adjusted so that the calculated terminal variables match the measurement results. There is a general accordance with model previsions, within common variations of the most critical properties, e.g. ground and ballast characteristics and rails permeability; the results are very accurate in the frequency range 50 Hz - 50 kHz.

Chester Franklin
ACTIVITIES OF THE NATIONAL COOPERATION FOR LABORATORY ACCREDITATION (NACLA) AND THE NATIONAL CONFERENCE OF STANDARDS LABORATORIES INTERNATIONAL (NCSLI)

NCSLI was established in 1961 to, “promote cooperative efforts for solving the common problems faced by measurement laboratories”. NACLA was established in 1998 to coordinate laboratory accreditation activities within the United States and to serve as the U.S. link to the worldwide accreditation system. NACLA ccomplishes its mission through various committees whose combined efforts lead to the evaluation of accreditation bodies (ABs) and granting recognition to ABs that are found to meet the international standard for competence; ISO/IEC Guide 58. NCSLI accomplishes its goals through the efforts of various technical committees that publish such documents as Recommended Practices, and through an accredited writing committee that produces documents for release as U.S. National Standards. The purpose of this paper is to present, in detail, the activities of these two organizations, in cooperation with the National Institute of Standards and Technology, and relate their efforts to one of the goals of the international metrology community: mutual recognition of measurements.

Jin-Tao Wang, Zi-Yong Liu, Long Zhang, Li-Gong Guo, Xue-Song Bao, Lin Tong
Research on Tank Volume Metrology for Petroleum and Liquid Petroleum Products Based on 3D Laser Scanning Method

One course radius measurement method for vertical tank volume metrology based on 3D laser scan principle was researched. Method of distance measurement by phase and angular measurement by optical grating was applied to acquire coordinates of points in each course under the control of servo system, and the permitted error of point location is 2 mm. Fitting algorithms base on direct iterative method (DIM) and least square method (LSM) were used to process measured data and deduce equivalent radius of each course. In comparison experiment, one 1000 m³ vertical tank was used as test object. Compared to strapping method (international mandatory standard), the maximal deviation radius value of method discussed is 2.8 mm, and the maximal difference of radius value calculated by DIM and LSM is 0.1 mm. The experimental results verified the method discussed in this paper.

Kazuto Kawakita, Rui Gomez Teixeira de Almeida
Frauds in the Measurement of Natural Gas

With the growing consumption of natural gas that has occurred in recent years, Brazil has also seen a great increase in the number of cases involving frauds in the measurement of this product, specifically concentrated at points where the gas companies distributes the product to the CNG stations. Such cases goes from a simple theft of gas from the pipeline using a by-pass to the meter, until a series of ingenious types of direct interventions on the gas metering system. Some of the fraudulently actions are being made even without the violation of the metrological physical sealing. Similar to the gas meters, the electronic gas volume converters are being defrauded. Besides the legal, economic and tributary issues, this problem impacts on the gas market because it may jeopardise the relationship between gas consumers and gas suppliers creating a confidence crisis, affecting all gas market and even delaying investments from gas companies. This article presents some of the frauds identified and shows some of the measures taken by the gas companies to remedy these problems, similarly to a cat-and-mouse game.

Shi Zhendong, Duan Huiming, Li Xu
Influence Factor of Verification of the Ultrasonic Heat Meter

The ultrasonic heat meter are more and more used in the supply heating system.The paper gives the principle of the ultrasonic heat meter and analyze influence factor when verifying the ultrasonic heat meter,it includes balance,thermostatic bath,standard Pt resistance,water density, sonic velocity,and etc. It emphasizes the influence of sonic velocity to verification.