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Item type:Publication, Access status: with files , Wireless and passive pressure detection using magneto-mechanical resonances in process engineering(IOP Publishing, 2025-08-31); ; ; ; A custom-developed magneto-mechanical resonator (MMR) for wireless pressure measurement is investigated for potential applications in process engineering. The MMR sensor utilises changes in the resonance frequency caused by pressure on a flexible 3D printed membrane. The thickness of the printed membrane plays a crucial role in determining the performance and sensitivity of MMRs and can be tailored to meet the requirements of specific applications. The study includes static and dynamic measurements to determine the pressure sensitivity and temporal resolution of the sensor. The results show a minimum sensitivity of 0.06 Hz mbar − 1 and are in agreement with theoretical calculations and measurements. The maximum sensor readout frequency is 2 Hz in this study. Additionally, the temperature dependence of the sensor is investigated, revealing a significant dependence of the resonance frequency on temperature. The developed MMR offers a promising and versatile method for precise pressure measurements in process engineering environments.Publicationtype: Journal Article75 70 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Using modelica to investigate the dynamic behaviour of the German national standard for high pressure natural gas flow meteringThis paper presents a computational model written in Modelica for the high pressure piston prover (HPPP) used as the national primary standard for high pressure natural gas flow metering in Germany. With a piston prover the gas flow rate is determined by measuring the time a piston needs to displace a certain volume of gas in a cylinder. Fluctuating piston velocity during measurement can be a significant source of uncertainty if not considered in an appropriate way. The model was built to investigate measures for the reduction of this uncertainty. Validation shows a good compliance of the piston velocity in the model with measured data for certain volume flow rates. Reduction of the piston weight, variation of the start valve switching time and integration of a flow straightener were found to reduce the piston velocity fluctuations in the model significantly. The fast and cost effective generation of those results shows the strength of the used modelling approach.Publicationtype: Journal ArticleScopus© Citations 1 265 362 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , In situ measurement of plasma and shock wave properties inside laser-drilled metal holesHigh-speed imaging of shock wave and plasma dynamics is a commonly used diagnostic method for monitoring processes during laser material treatment. It is used for processes such as laser ablation, cutting, keyhole welding and drilling. Diagnosis of laser drilling is typically adopted above the material surface because lateral process monitoring with optical diagnostic methods inside the laser-drilled hole is not possible due to the hole walls. A novel method is presented to investigate plasma and shock wave properties during the laser drilling inside a confined environment such as a laser-drilled hole. With a novel sample preparation and the use of high-speed imaging combined with spectroscopy, a time and spatial resolved monitoring of plasma and shock wave dynamics is realized. Optical emission of plasma and shock waves during drilling of stainless steel with ns-pulsed laser radiation is monitored and analysed. Spatial distributions and velocities of shock waves and of plasma are determined inside the holes. Spectroscopy is accomplished during the expansion of the plasma inside the drilled hole allowing for the determination of electron densities.Publicationtype: Journal Article13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , In-situ moisture detection system with a vector network analyserAn in-situ measuring system for determining the moisture content in concrete buildings and masonry is presented. The system consists of a small and robust resonant microwave sensor and a compact low-cost network analyser. The sensitivity and frequency range requirements for the analyser are derived from the sensor design. A suitable realization of the analyser is discussed in detail. It is shown that a vectorial calibration routine diminishes measurement uncertainties caused by the used low-cost devices. Consequently, the moisture content can be determined within 0.6% instead of 3.0%. A test of the entire in-situ measurement system under realistic conditions is presented and discussed. © 2007 IOP Publishing Ltd.Publicationtype: Journal Article42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A landmark-based 3D calibration strategy for SPM(2007-02); ; ; We present a new method for the complete three-dimensional (3D) calibration of scanning probe microscopes (SPM) and other high-resolution microscopes, e.g., scanning electron microscopes (SEM) and confocal laser scanning microscopes (CLSM), by applying a 3D micrometre-sized reference structure with the shape of a cascade slope-step pyramid. The 3D reference structure was produced by focused ion beam induced metal deposition. In contrast to pitch featured calibration procedures that require separate lateral and vertical reference standards such as gratings and step height structures, the new method includes the use of landmarks, which are well established in calibration and measurement tasks on a larger scale. However, the landmarks applied to the new 3D reference structures are of sub-micrometre size, the so-called 'nanomarkers'. The nanomarker coordinates are used for a geometrical calibration of the scanning process of SPM as well as of other instrument types such as SEM and CLSM. For that purpose, a parameter estimation routine involving three scale factors and three coupling factors has been developed that allows lateral and vertical calibration in only one sampling step. With this new calibration strategy, we are able to detect deviations of SPM lateral scaling errors as well as coupling effects causing, e.g., a lateral coordinate shift depending on the measured height position of the probe. © 2007 IOP Publishing Ltd.Publicationtype: Conference Paper16