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Page 6 of 891 Results 51 - 60 of 8905

V. Sedlák, D. Pražák, J. Tesař, D. Rosu, G. Geršak, M. Ferreira, M. Nawotka, A. Bosnjakovic, E. Jugo, P. Hetherington, A. Duffy, P. Pavlásek
EVALUATION OF SPHYGMOMANOMETERS USING AN ADVANCED OSCILLOMETRIC SIGNAL GENERATOR

Reliable and accurate blood pressure measurements using sphygmomanometers are indispensable in the diagnostic and treatment of hypertension. Unfortunately, testing of performance and accuracy of automated oscillometric sphygmomanometers is complicated, lengthy and expensive. Fact that the oscillometric sphygmomanometers are majority of the blood pressure measuring devices on today’s market makes the problem more pressing. EMPIR project adOSSIG built a physiologybased advanced blood pressure simulator with a goal of improving blood pressure measurements. This paper describes results of testing of sphygmomanometers using this newly developed simulator.

A. Carbone, F. Tartarelli, M. Lazzaroni, S. Latorre
QUALITY ASSURANCE AND TESTING OF THE ATLAS LIQUID ARGON CALORIMETER POWER DISTRIBUTION BOARDS

During the second Large Hadron Collider Long Shutdown, the Liquid Argon calorimeter of the ATLAS experiment at CERN has been upgraded with a new trigger readout electronics which provides digital information with higher granularity to the ATLAS trigger system. In particular the new LAr Trigger Digitizer Boards will process and digitize the "Super Cells" (group of readout calorimeters cells) and send the processed data to the back-end electronics. The Power Distribution Board is a mezzanine board that provides the power distribution to the LTDB.

Kenan Varda, Almira Softić, Nermina Zaimović-Uzunović, Ernad Bešlagić
COMPARISON OF DIMENSIONS, SHAPES AND POSITIONS CONTROL USING CMM AND 3D SCANNER

In this paper, measurements on stainless steel AISI 304 workpiece using Coordinate measuring machine Carl Zeiss Contura G2 and 3D scanner RangeVision PRO are compared and analyzed. Dimensional control is conducted by measuring 11 faces and 9 cylinders. Length, diameter, cylindricity, flatness and parallelism are controlled for features of interest. Using Calypso software on CMM and GOM Inspect software for 3D scanned model are used for creating virtual measurement strategies and dimensional and GD&T control. Deviations of measuring results using both measuring systems are shown and conclusions and recommendations for dimensional control are listed in tables.

G. P. Ripper, R. S. Dias, G. B. Micheli, C. D. Ferreira
AN ANALYSIS OF THE PARTICIPATION OF INMETRO IN INTERLABORATORY COMPARISONS IN VIBRATION MEASUREMENTS

This paper provides an overview of the participation of INMETRO on vibration interlaboratory comparisons along the last years and analyses the benefits of having an active participation in such activities.

A. Savarin, A. Chijioke
MEASUREMENT OF DYNAMIC ROCKING IN SINUSOIDAL CALIBRATION WITH AN ELECTRODYNAMIC SHAKER

Rocking motion is often a significant source of uncertainty in sinusoidal calibrations of accelerometers and force transducers. We describe real-time measurements of rocking during sinusoidal excitation, performed at NIST. The measurement is contactless and can be performed simultaneously with the motion. We report rocking measurements for excitation frequencies up to 2 kHz. The results obtained have an absolute uncertainty (k = 2) in the range of 0.02 µrad to 3.3 µrad and allow error due to rocking motion to be largely corrected in axial acceleration measurement.

Anderson K. Maina, Christiaan S. Veldman
MINIMISING THE EFFECTS OF SPURIOUS RESONANCES IN SECONDARY VIBRATION CALIBRATION

This paper explores the use of fitted sensitivity values in order to minimize the effects of spurious resonances in the frequency response of reference accelerometers used in secondary vibration calibration.

Andreas Havreland
ELECTRICAL IMPEDANCE BASED CALIBRATION OF ACCELEROMETERS

This contribution proposes a methodology to predict the transfer function of an accelerometer solely based on an electrical impedance measurement. Such impedance measurement can be conducted in-situ and has certain advantages for some types of accelerometers and under certain measuring conditions. A proof-of-concept study has been conducted where the methodology is used to estimate the sensitivity at 160 Hz, the proposed method underestimates the sensitivity by 9% compared to a conventional vibration experiment.

Jacob Holm Winther, Martin Brucke, Martin Thalbitzer Andersen, Torben Rask Licht
RECENT STUDY IN PRIMARY ACCELEROMETER CALIBRATION - PROGRESS, DEVELOPMENT AND LESSONS LEARNED

Primary calibration of accelerometers by laser interferometry has been performed for more than 50 years. It was made possible by the advent of the commercial He-Ne lasers in the 1960ties. During the last 20 years the progress in digital signal treatment has made it available for most interested laboratories.
However, these huge progresses have merely reduced but not removed some basic problems.
- The quality and basic parameters of the exciter systems
- The influence from the mechanical setup on the accelerometer and thereby on the measurement results.
This paper describes several topics and considerations found relevant for primary calibration of accelerometers, following recent international intercomparisons and progress in the calibration grade vibration exciter system design.

J. Berry, P. Lovelock, I. A. Robinson, J. Urquhart
VIBRATIONAL ANALYSIS FOR THE NEXT GENERATION NPL KIBBLE BALANCE

Low uncertainty Kibble balance measurements require careful consideration of the effect of external sources of vibration. This paper compares vibrational modelling of the machine frame of the National Physical Laboratory’s next generation Kibble balance using three different software packages. The output of the modelling on the machine frame showed that the first modes of vibration were all above the design requirement of 60 Hz.
The model was then enhanced to include the moving section of the balance modelled with two types of guidance mechanism. The output from the modelling showed a reduction in the resilience of the balance to lateral vibrations but the linkage type guidance mechanism was still resilient to induced vibrations at frequencies up to 50 Hz.

Henrik Volkers, Benedikt Seeger
USING COMMONLY AVAILABLE NETWORK EQUIPMENT FOR LASER DOPPLER VIBROMETER EXCITATION AND CALIBRATION

We have demonstrated that commonly available small form-factor pluggable (SFP) modules can be used for LDV excitation and calibration. While the expected intensity modulation at the photodiode inside the LDV interferometer is sinusoidal, the SFP module output is designed for and provides a rectangular modulation shape. The conducted experiments produced comparable results.

Page 6 of 891 Results 51 - 60 of 8905