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...
An experimental electrometric set-up, conceived as a physical model of a metrological system for electric-watt realisation or Planck constant determination, has been operated in a persistent oscillatory mode. In this condition, the behaviour of a moving element in levitation and in vacuum is simulated. An experimental test of the relation between the frequency of the oscillation and the bias voltage of the fixed electrodes confirms the possibility of including such a relation in the set of equations from which the geometrical constant can be eliminated. Metrological exploitation of the...
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...
This paper is an overview of the activities in the field of AC-DC transfer at BNM-LNE. Thermal converters, measurement principles and techniques are described. The different domains covered by AC-DC transfer at BNM-LNE are presented with indication of achievable uncertainties for each of them.
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....
Flow metering devices are one of the most important apparatus to measure/control fluid flows in pipelines, including industries such as chemical/petroleum plants, as well as residential/municipal facilities. In recent years, the systems have advanced into digital era with the development of science and technology. However, batteries and wired electricity are still the major operating power. In this proposed "Self-Powered Pipe Flow Metering System (SPPFM)", the pipe flow drives the rotor of a generator to power the measuring unit itself. Thanks to the system, only small part of the flow power...
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...
In the theoretical assessment of accuracy of rotary piston meters, the leakage flow in the rotor-casing gap is of essential importance. The present work aimed at detailed investigation of this flow field employing realistic numerical flow simulation. The resulting flow displayed significant differences to the simple assumption.
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.
The accuracy of gas flow meter field measurement is directly associated with the economic benefits of both parties of the business. Thus, the accuracy of flow measurement is getting more and more attention. The field inspection, examination, and calibration of the gas flow meter are effective way and method to ensure the accuracy of gas measurement. The article explores and analyzes the method of using mobile standard device to online calibrate the gas flow meter, and proposes an accurate and reliable suggestion for ensuring the field examination of flow meter.