Description of the Coupling of two Loop Antennas using Electrical Equivalent Circuit Diagrams

EMC measurements must be carried out in standardized and defined measuring environments. The frequency range between 9 kHz and 30 MHz is a major challenge for measurement technology. The established test sites are designed with an perfect elelctrically conducting ground. For the considered lower frequency range, the metrological validation is carried out with magnetic field antennas in this frequency range. The aim is therefore to take into account the ferromagnetic properties of the ground plane in such a measurement environment and to describe them analytically or numerically with an electrical equivalent circuit diagram. In this article we simplify the model to two loopantennas in Freespace without groundplane to check if the approache with the ECD will work. Therefore we use various numerical field calculation programs in the frequency range up to 30 MHz. The results from simulations are to be checked for correctness with describing them analytically or numerically. For this purpose, a model consisting of two loop antennas was created and simulated in a numerical simulation program. In order to validate the results from the simulation, two different approaches to creating an electrical equivalent circuit (ECD) are examined. The first approach is based on the real equivalent circuit diagram of a coil and the second approach forms a parallel resonant circuit of the first resonance of an antennas input impedance. The focus here is on the mutual inductance, which represents the coupling between the two antennas.

Absolute, pressure-dependent validation of a calibration-free, airborne laser hygrometer transfer standard (SEALDH-II) from 5 to 1200 ppmv using a metrological humidity generator

Highly accurate water vapor measurements are indispensable for understanding a variety of scientific questions as well as industrial processes. While in metrology water vapor concentrations can be defined, generated, and measured with relative uncertainties in the single percentage range, field-deployable airborne instruments deviate even under quasistatic laboratory conditions up to 10–20 %. The novel SEALDH-II hygrometer, a calibration-free, tuneable diode laser spectrometer, bridges this gap by implementing a new holistic concept to achieve higher accuracy levels in the field. We present in this paper the absolute validation of SEALDH-II at a traceable humidity generator during 23 days of permanent operation at 15 different H2O mole fraction levels between 5 and 1200 ppmv. At each mole fraction level, we studied the pressure dependence at six different gas pressures between 65 and 950 hPa. Further, we describe the setup for this metrological validation, the challenges to overcome when assessing water vapor measurements on a high accuracy level, and the comparison results. With this validation, SEALDH-II is the first airborne, metrologically validated humidity transfer standard which links several scientific airborne and laboratory measurement campaigns to the international metrological water vapor scale.

SEALDH-II – a calibration-free transfer standard for airborne water vapor measurements: Pressure dependent absolute validation from 5–1200 ppmv at a metrological humidity generator

Highly accurate water vapor measurements are indispensable for understanding a variety of scientific questions as well as industrial processes. While in metrology water vapor concentrations can be defined, generated and measured with relative uncertainties in the single percentage range, field deployable airborne instruments deviate even under quasi-static laboratory conditions up to 10–20 %. The novel SEALDH-II hygrometer, a calibration-free, tuneable diode laser spectrometer, bridges this gap by implementing an entirely new concept to achieve higher accuracy levels in the field. Here we present the absolute validation of SEALDH-II at a traceable humidity generator during 23 days of permanent operation at 15 different H2O concentration levels between 5 and 1200 ppmv. At each concentration level, we studied the pressure dependence at 6 different gas pressures between 65 and 950 hPa. Further, we describe the setup for this metrological validation, the challenges to overcome when assessing water vapor measurements on a high accuracy level, as well as the comparison results. With this validation, SEALDH-II is the first metrologically validated humidity transfer standard which links several scientific airborne and laboratory measurement campaigns to the international metrological water vapor scale.

NON-INTRUSIVE METHOD FOR MEASURING WATER FLOW RATE IN PIPE

The transducer most widely used for vibration measurement is the piezoelectric accelerometer. This application has been explored for flow rate measurement, since some studies have verified the narrow correlation between ratio of flow and vibration. The technique consists of measure the vibration induced by the flow in the pipeline, has been considered as promising, in the sense of enabling the development of a sensor that presents advantageous characteristics such as non-intrusiveness, non-invasiveness and reduced cost. This paper shows the method of measurement of flow in pipe based on vibration caused by transit of water, without the need of flow interruption or opening of pipe for installation of water meters. Further are present experimental measurements and metrological validation in laboratory accredited for calibration of flow meters.