Infra-AUV project: Metrology for low-frequency sound and vibration

2021 ◽  
Author(s):  
Lars Ceranna ◽  
Thomas Bruns ◽  
Christian Koch ◽  
Dominique Rodrigues ◽  
Stephen Robinson ◽  
...  
Keyword(s):  
Low Frequency ◽  
Monitoring Networks ◽  
Vibration Data ◽  
In Situ Calibration ◽  
Laboratory Calibration ◽  
Calibration Methods ◽  
National Measurement ◽  
Eu Project

<p>Infra-AUV is a new EU project that will establish primary measurements standards for low frequency phenomena across the fields of airborne and underwater acoustics and vibration (seismology). Combining expertise from the national measurement institutes and geophysical monitoring station operators, it will develop both high-precision laboratory-based methods of calibration and methods suitable for field use. Infra-AUV will also address requirements for reference sensors that link laboratory calibration capabilities to field requirements for measurement traceability.</p><p>To establish standards in the three technical areas, a variety of calibration principles will be employed, including extension of existing techniques such as reciprocity and optical interferometry, and development of new methods. There will also be an investigation of the potential for in-situ calibration methods, including use of both artificially generated and naturally occurring stimuli such as microseisms and microbaroms. The influence of calibration uncertainties on the determination of the measurands required by the monitoring networks will also be studied.</p><p>The project was strongly motivated by the CTBTO strategy to drive new metrology capability to underpin IMS data. The intention is to maintain interaction with stakeholders, not only in connection with the IMS, but with the broad range of users of low frequency acoustic and vibration data. </p>

scholarly journals Performance of the SoLid reactor neutrino detector

2019 ◽  
Vol 219 ◽  
pp. 08003
Author(s):  
Maja Verstraeten
Keyword(s):  
Quality Control ◽  
Energy Resolution ◽  
Neutrino Detector ◽  
Channel Response ◽  
In Situ Calibration ◽  
Reactor Neutrino ◽  
Li Isotope ◽  
Better Than

The SoLid Collaboration is currently operating a 1.6 ton neutrino detector near the Belgian BR2 reactor. Its main goal is the observation of the oscillation of electron antineutrinos to previously undetected flavour states. The highly segmented SoLid detector employs a compound scintillation technology based on PVT scintillator in combination with LiF-ZnS(Ag) screens containing the 6Li isotope. The experiment has demonstrated a channel-to-channel response that can be controlled to the level of a few percent, an energy resolution of better than 14% at 1 MeV, and a determination of the interaction vertex with a precision of 5 cm. This contribution highlights the major outcomes of the R&D program, the quality control during component manufacture and integration, the current performance and stability of the full-scale system, as well as the in-situ calibration of the detector with various radioactive sources.

In situ calibration and [H+] sensitivity of the fluorescent Na+indicator SBFI

2001 ◽  
Vol 280 (6) ◽  
pp. C1623-C1633 ◽  
Author(s):  
Abdoullah Diarra ◽  
Claire Sheldon ◽  
John Church
Keyword(s):  
Ph Dependence ◽  
Apparent Dissociation Constant ◽  
Simple Method ◽  
Standard Equation ◽  
In Situ Calibration ◽  
Apparent Decrease ◽  
Calibration Techniques

Despite the popularity of Na+-binding benzofuran isophthalate (SBFI) to measure intracellular free Na+ concentrations ([Na+]i), the in situ calibration techniques described to date do not favor the straightforward determination of all of the constants required by the standard equation (Grynkiewicz G, Poenie M, and Tsien RY. J Biol Chem 260: 3440–3450, 1985) to convert the ratiometric signal into [Na+]. We describe a simple method in which SBFI ratio values obtained during a “full” in situ calibration are fit by a three-parameter hyperbolic equation; the apparent dissociation constant ( K d) of SBFI for Na+ can then be resolved by means of a three-parameter hyperbolic decay equation. We also developed and tested a “one-point” technique for calibrating SBFI ratios in which the ratio value obtained in a neuron at the end of an experiment during exposure to gramicidin D and 10 mM Na+is used as a normalization factor for ratios obtained during the experiment; each normalized ratio is converted to [Na+]i using a modification of the standard equation and parameters obtained from a full calibration. Finally, we extended the characterization of the pH dependence of SBFI in situ. Although the K d of SBFI for Na+ was relatively insensitive to changes in pH in the range 6.8–7.8, acidification resulted in an apparent decrease, and alkalinization in an apparent increase, in [Na+]i values. The magnitudes of the apparent changes in [Na+]ivaried with absolute [Na+]i, and a method was developed for correcting [Na+]i values measured with SBFI for changes in intracellular pH.

scholarly journals In Situ Calibration of a New Chemcatcher Configuration for the Determination of Polar Organic Micropollutants in Wastewater Effluent

2016 ◽  
Vol 50 (17) ◽  
pp. 9469-9478 ◽  
Author(s):  
Bruce Petrie ◽  
Anthony Gravell ◽  
Graham A. Mills ◽  
Jane Youdan ◽  
Ruth Barden ◽  
...  
Keyword(s):  
Wastewater Effluent ◽  
Organic Micropollutants ◽  
In Situ Calibration

An Investigation Into Acoustic Dipole Source Calibration Methods for Turbomachinery Sound Radiation in Reverberant Fields

2016 ◽  
Author(s):  
Michael L. Jonson ◽  
Steven D. Young
Keyword(s):  
Near Field ◽  
Dipole Source ◽  
Acoustic Source ◽  
In Situ Calibration ◽  
Calibration Methods ◽  
Penn State ◽  
Radiated Sound ◽  
Reverberant Field ◽  
Dipole Sources

In-situ calibration methods using a single spherical-shaped transmitting hydrophone (idealized as a monopole acoustic source) have traditionally been used for radiated sound measurements of turbomachinery performed in the Garfield Thomas 1.22-m diameter water tunnel located at The Pennsylvania State University’s Applied Research Laboratory (ARL Penn State). In this reverberant field, the monopole source containing known transmitting characteristics was used to calibrate acoustic sensors that were either near or far from the source. This method typically works well when the type of source is monopole in nature; however, many acoustics sources can be dipole or quadrupole in nature. In this study we investigated the applicability of using dipole sources in a space such as a well-characterized reverberant tank, and we found through a virtual dipole method that the radiation still appears monopole in the reverberant field. The method was extended for the vibration of a panel (a known dipole source) and once again the monopole assumption for the in-situ calibration for a near-field hydrophone and conventional reverberant hydrophones remained consistent.

scholarly journals RAPID RADIOMETRIC CALIBRATION OF MULTIPLE CAMERA ARRAY USING IN-SITU DATA FOR UAV MULTISPECTRAL PHOTOGRAMMETRY

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 209-215
Author(s):  
R. Minařík ◽  
J. Langhammer
Keyword(s):  
Statistical Testing ◽  
Radiometric Calibration ◽  
Accuracy Improvement ◽  
Raw Data ◽  
Multiple Camera ◽  
In Situ Data ◽  
In Situ Calibration ◽  
Laboratory Calibration ◽  
Uav Images

Abstract. This study compares two possible radiometric calibration approaches of Tetracam μMCA Snap multispectral camera using the Dark offset subtraction and Look-Up Table (LUT) methods. A laboratory-based calibration using correction images taken under the controlled conditions was compared with a rapid in-situ based calibration featuring correction images taken during the field campaign. The hypothesis was that the accuracy of in-situ calibration could be comparable with the laboratory calibration, and thus could replace it and simplify the radiometric calibration process. The accuracy of calibration approaches was assessed by comparison of three validation targets reflectance values extracted from corrected UAV images based on laboratory and in-situ calibration with a reference spectroscopy measurement. The results of the field experiment showed that both calibration approaches led to significant accuracy improvement compared to raw data. The vignetting correction using resulted in a significant reduction of the Coefficient of variation by half in all bands and overall equalizing the DNs on the selected diagonal profile. The NRMSEs after processing all corrections ranged from 0.24 to 3.40%. Although the statistical testing revealed slightly better agreement of laboratory calibrated reflectance with reference data, the accuracy of in-situ calibration is sufficient, because the accuracy improvement quantified by the NRMSE is 2–10 times better using both calibration approaches compared to raw data than the NRMSE differences between them. These findings make the proposed in-situ approach usable for various environmental studies featuring UAV multispectral photogrammetry.

scholarly journals Six-Axis Force Torque Sensor Model-Based In Situ Calibration Method and Its Impact in Floating-Based Robot Dynamic Performance

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5521
Author(s):  
Francisco Javier Andrade Chavez ◽  
Silvio Traversaro ◽  
Daniele Pucci
Keyword(s):  
Dynamic Performance ◽  
Calibration Method ◽  
Full Description ◽  
Temperature Drift ◽  
Model Based ◽  
Floating Base ◽  
In Situ Calibration ◽  
Calibration Methods ◽  
The Impact

A crucial part of dynamic motions is the interaction with other objects or the environment. Floating base robots have yet to perform these motions repeatably and reliably. Force torque sensors are able to provide the full description of a contact. Despite that, their use beyond a simple threshold logic is not widespread in floating base robots. Force torque sensors might change performance when mounted, which is why in situ calibration methods can improve the performance of robots by ensuring better force torque measurements. The Model-Based in situ calibration method with temperature compensation has shown promising results in improving FT sensor measurements. There are two main goals for this paper. The first is to facilitate the use and understanding of the method by providing guidelines that show their usefulness through experimental results. Then the impact of having better FT measurements with no temperature drift are demonstrated by proving that the offset estimated with this method is still useful days and even a month from the time of estimation. The effect of this is showcased by comparing the sensor response with different offsets simultaneously during real robot experiments. Furthermore, quantitative results of the improvement in dynamic behaviors due to the in situ calibration are shown. Finally, we show how using better FT measurements as feedback in low and high level controllers can impact the performance of floating base robots during dynamic motions. Experiments were performed on the floating base robot iCub.

scholarly journals Dissolved Oxygen Measurement in Seawater and Sensor Calibration Method

2021 ◽  
Vol 299 ◽  
pp. 02017
Author(s):  
Shun Gao ◽  
Yingying Zhang ◽  
Xiandong Feng ◽  
Da Yuan ◽  
Bingwei Wu ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Automatic Monitoring ◽  
Calibration Method ◽  
Oxygen Sensors ◽  
Sensor Calibration ◽  
Advantages And Disadvantages ◽  
In Situ Calibration ◽  
Laboratory Calibration ◽  
Calibration Methods ◽  
Working Principle

The development and key calibration methods of the sensors for the measurement and automatic monitoring of dissolved oxygen in seawater have always been the research focus in the field of Marine monitoring technology. This paper summarizes the measurement methods of dissolved oxygen in seawater, the working principle and advantages and disadvantages of different dissolved oxygen sensors, and the research on calibration methods of mainstream optical dissolved oxygen sensors. Especially for optical dissolved oxygen sensors with better stability, longer service life and stronger anti-interference ability, several laboratory calibration methods which have been developed and applied, as well as in situ calibration methods which are still in the research stage are analyzed.

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