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Frequency-Resolved High-Frequency Broadband Measurement of Acoustic Longitudinal Waves by Laser-Based Excitation and Detection

Brand, Felix; Drese, Klaus Stefan (2024)

Sensors 24 (5), S. 1630.
DOI: 10.3390/s24051630


Open Access Peer Reviewed
 

Optoacoustics is a metrology widely used for material characterisation. In this study, a measurement setup for the selective determination of the frequency-resolved phase velocities and attenuations of longitudinal waves over a wide frequency range (3-55 MHz) is presented. The ultrasonic waves in this setup were excited by a pulsed laser within an absorption layer in the thermoelastic regime and directed through a layer of water onto a sample. The acoustic waves were detected using a self-built adaptive interferometer with a photorefractive crystal. The instrument transmits compression waves only, is low-contact, non-destructive, and has a sample-independent excitation. The limitations of the approach were studied both by simulation and experiments to determine how the frequency range and precision can be improved. It was shown that measurements are possible for all investigated materials (silicon, silicone, aluminium, and water) and that the relative error for the phase velocity is less than 0.2%.

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Guided Acoustic Waves in Polymer Rods with Varying Immersion Depth in Liquid

Lutter, Klaus; Backer, Alexander; Drese, Klaus Stefan (2023)

Sensors 2023 (23), S. 9892.
DOI: 10.3390/s23249892


Open Access Peer Reviewed
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A photoacoustic based measurement system for dual detection of NO2 and CO2 in combustion exhaust gases

Panzardi, Enza; Drese, Klaus Stefan; Mugnaini, Marco; Parri, Lorenzo ; Vignoli, Valerio...

IEEE Transactions on Instrumentation and Measurement 2023.
DOI: 10.1109/TIM.2023.3328691


Peer Reviewed
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Phase Modulated Frequency Shifted Digital Holographic Vibrometry with Enhanced Robustness

Dötzer, Florian; Hommel, Markus; Drese, Klaus Stefan; Sinzinger, Stefan (2023)

EPJ Web of Conferences 2023, 09017 (287).
DOI: 10.1051/epjconf/202328709017


Open Access
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Quantification of Moisture in Masonry via AI Evaluated Broadband Radar Reflectometry

Frenzel, Daniel; Blaschke, Oliver; Franzen, Christoph; Brand, Felix; Haas, Franziska...

Vortrag: Salt Weathering of Buildings and Stone Sculptures Asia 2023, S. 195-206.



Quantification of Moisture in Masonry via AI-Evaluated Broadband Radar Reflectometry

Frenzel, Daniel; Blaschke, Oliver; Franzen, Christoph; Brand, Felix; Haas, Franziska...

Heritage 6 (7), S. 5030-5050.
DOI: 10.3390/heritage6070266


Open Access Peer Reviewed
 

Humidity, salt content, and migration in building materials lead to weathering and are a common challenge. To understand damage phenomena and select the right conservation treatments, knowledge on both the amount and distribution of moisture and salt load in the masonry is crucial. It was shown that commercial portable devices addressing moisture are often limited by the mutual interference of these values. This can be improved by exploiting broadband radar reflectometry for the quantification of humidity in historic masonry. Due to the above-mentioned limitations, today’s gold standard for evaluating the moisture content in historic buildings is still conducted by taking drilling samples with a subsequent evaluation in a specially designed laboratory, the so-called Darr method. In this paper, a new broadband frequency approach in the range between 0.4 and 6 GHz with improved artificial-intelligence data analysis makes sure to optimize the reflected signal, simplify the evaluation of the generated data, and minimise the effects of variables such as salt contamination that influence the permittivity. In this way, the amount of water could be determined independently from the salt content in the material and an estimate of the salt load. With new machine learning algorithms, the analysis of the permittivity is improved and can be made accessible for everyday use on building sites with minimal intervention by the user. These algorithms were trained with generated data from different drying studies on single building bricks from the masonries. The findings from the laboratory studies were then validated and evaluated on real historic buildings at real construction sites. Thus, the paper shows a spatially resolved and salt-independent measurement system for determining building moisture.

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Ultrasonic Interferometric Procedure for Quantifying the Bone–Implant Interface

Lützelberger, Jan; Arneth, Philipp; Franck, Alexander; Drese, Klaus Stefan (2023)

Sensors 23 (13), S. 5942.
DOI: 10.3390/s23135942


Open Access Peer Reviewed
 

The loosening of an artificial joint is a frequent and critical complication in orthopedics and trauma surgery. Due to a lack of accuracy, conventional diagnostic methods such as projection radiography cannot reliably diagnose loosening in its early stages or detect whether it is associated with the formation of a biofilm at the bone–implant interface. In this work, we present a non-invasive ultrasound-based interferometric measurement procedure for quantifying the thickness of the layer between bone and prosthesis as a correlate to loosening. In principle, it also allows for the material characterization of the interface. A well-known analytical model for the superposition of sound waves reflected in a three-layer system was combined with a new method in data processing to be suitable for medical application at the bone–implant interface. By non-linear fitting of the theoretical prediction of the model to the actual shape of the reflected sound waves in the frequency domain, the thickness of the interlayer can be determined and predictions about its physical properties are possible. With respect to determining the layer’s thickness, the presented approach was successfully applied to idealized test systems and a bone–implant system in the range of approx. 200 µm to 2 mm. After further optimization and adaptation, as well as further experimental tests, the procedure offers great potential to significantly improve the diagnosis of prosthesis loosening at an early stage and may also be applicable to detecting the formation of a biofilm.

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Quantification of Humidity and Salt Detection in Historical Building Materials via Broadband Radar Measurement

Blaschke, Oliver; Brand, Felix; Drese, Klaus Stefan (2023)

Sensors 23 (10), S. 4616.
DOI: 10.3390/s23104616


Open Access Peer Reviewed
 

For the investigation of moisture and salt content in historic masonry, destructive drilling samples followed by a gravimetric investigation is still the preferred method. In order to prevent the destructive intrusion into the building substance and to enable a large-area measurement, a nondestructive and easy-to-use measuring principle is needed. Previous systems for moisture measurement usually fail due to a strong dependence on contained salts. In this work, a ground penetrating radar (GPR) system was used to determine the frequency-dependent complex permittivity in the range between 1 and 3 GHz on salt-loaded samples of historical building materials. By choosing this frequency range, it was possible to determine the moisture in the samples independently of the salt content. In addition, it was possible to make a quantitative statement about the salt level. The applied method demonstrates that with ground penetrating radar measurements in the frequency range selected here, a salt-independent moisture determination can be carried out.

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On Dispersion Compensation for GAW-Based Structural Health Monitoring

Backer, Alexander; Fairuschin, Viktor; Drese, Klaus Stefan (2023)

Sensors 23 (9), S. 4282.
DOI: 10.3390/s23094282


Open Access Peer Reviewed
 

Guided acoustic waves (GAW) have proven to be a useful tool for structural health monitoring (SHM). However, the dispersive nature of commonly used Lamb waves compromises the spatial resolution making it difficult to detect small or weakly reflective defects. Here we demonstrate an approach that can compensate for the dispersive effects, allowing advanced algorithms to be used with significantly higher signal-to-noise ratio and spatial resolution. In this paper, the sign coherence factor (SCF) extension of the total focusing method (TFM) algorithm is used. The effectiveness is examined by numerical simulation and experimentally demonstrated by detecting weakly reflective layers with a highly dispersive A0 mode on an aluminum plate, which are not detectable without compensating for the dispersion effects.

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Highly Sensitive Photoacoustic NO 2 Measurement System Based on an Optimized Ring-Shaped Resonant Cell

Fort, Ada; Mugnaini, Marco; Panzardi, Enza; Vignoli, Valerio; Dötzer, Florian...

IEEE Transactions on Instrumentation and Measurement 2023 (72), S. 1-10.
DOI: 10.1109/TIM.2023.3244222


Peer Reviewed
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Acoustic Limescale Layer and Temperature Measurement in Ultrasonic Flow Meters

Landskron, Johannes; Dötzer, Florian; Benkert, Andreas ; Mayl, Michael ...

Sensors 2022 (2), S. 6648.
DOI: 10.3390/s22176648


Open Access Peer Reviewed
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Elastic Properties Measurement Using Guided Acoustic Waves

Fairuschin, Viktor; Brand, Felix; Backer, Alexander; Drese, Klaus Stefan (2021)

Sensors 2021 (19).
DOI: 10.3390/s21196675


Open Access Peer Reviewed
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Highly Sensitive Photoacoustic NO 2 Measurement System Based on an Optimized Ring-Shaped Resonant Cell

Fort, Ada; Panzardi, Enza; Vignoli, Valerio; Landi, Elia; Mugnaini, Marco...

2021 IEEE International Workshop on Metrology for Industry 4.0 & IoT 2021, S. 583-587.
DOI: 10.1109/MetroInd4.0IoT51437.2021.9488532


Peer Reviewed
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Actuation of Liquid Flow by Guided Acoustic Waves on Punched Steel Tapes with Protruding Loops

Backer, Alexander; Landskron, Johannes; Drese, Klaus Stefan; Lindner, Gerhard (2021)

Journal of Bionic Engineering 2021 (18), S. 534–547.
DOI: 10.1007/s42235-021-0051-x


Open Access Peer Reviewed
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NO2 photoacoustic sensing system based on resonant cell and UV-LED sensor

Fort, Ada; Panzardi, Enza; Vignoli, Valerio; Landi, Elia; Mugnaini, Marco...

2021 IEEE International Workshop on Metrology for Industry 4.0 & IoT (MetroInd4. 0&IoT) 2021, S. 583-587.
DOI: 10.1109/MetroInd4.0IoT51437.2021.9488532


Peer Reviewed
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Excitation of Guided Acoustic Waves Using Ignition Sparks

Krempel, Sandro; Backer, Alexander; Dötzer, Florian; Drese, Klaus Stefan (2021)

SMSI 2021-Sensors and Instrumentation.
DOI: 10.5162/SMSI2021/A9.1


Open Access
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Generating Homogeneous Gas Mixtures by Using Acoustic Waves

Krempel, Sandro; Seidel, N.; Tietze, Sabrina; Drese, Klaus Stefan (2021)

ACTUATOR; International Conference and Exhibition on New Actuator Systems and Applications 2021.



Ship Propulsion by Means of Acoustic Radiation

Backer, Alexander; Krempel, Sandro; Ritter, Frank; Tietze, Sabrina...

ACTUATOR, International Conference and Exhibition on New Actuator Systems and Applications 2021, Online 2021, S. 66 - 69.


 

Nowadays in almost all cases, the propulsion of ships is generated by mechanically moved propellers, which causes water flow and thrust. The disadvantage of this technology is the wear of the mechanical moving parts as well as the danger of the rotating parts in the water for example for living beings. The only alternative is still the sail or wind power.
In our approach the propulsion of a boat is generated without moving parts by means of ultrasonic waves emitted into
the water. In contrast to already existing experiments in which surface acoustic waves are conducted directly into the
water on piezoelectric substrates in order to generate a thrust, here the sound input takes place by piezoelectric transducers attached to the backside of non-piezoelectric material at the outer hull of the boat. A 3D printed model boat was
built and tested. In contrast to the previously published literature, the used electronic components and their operation for
the propulsion of the boat are described in detail. Sound generation and propagation are simulated in COMSOL


Modeling of acoustic enhanced electrochemical polishing processes.

Landskron, Johannes; Tietze, Sabrina; Wolf, Conrad R.; Drese, Klaus Stefan (2020)

Vortrag auf der Acoustofluidics 2020.


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Ultraschallbasierte Dehydratationsmessung zum unterstützenden Gesundheitsmonitoring

Roßteutscher, Immanuel; Ros, M.; Schwuchow, K.; Wolny, C.; Drese, Klaus Stefan (2020)

Jahresmagazin Mess- und Sensortechnik 2020/2021 2020, S. 42–44.


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