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Page 378 of 977 Results 3771 - 3780 of 9762

Adriana Vâlcu, Alina Taină, Roberta Todor
THE PERFORMANCE EVALUATION OF LABORATORIES PERFORMING CALIBRATION OF NON-AUTOMATIC WEIGHING INSTRUMENTS (NAWI)

In 2014, a proficiency testing in the field of NAWI calibration was carried out at National Institute of Metrology (INM) from Romania. The accredited provider of this proficiency testing scheme was ROLAB Association. The subject of the comparison consisted in a weighing instrument having Max 6000 g and d = 0.01 g. The paper presents the results obtained by eleven participating laboratories in this proficiency testing scheme. All results were in agreement with the results of INM.

Satu Rajala, Maija Vuoriluoto, Orlando J. Rojas, Sami Franssila, Sampo Tuukkanen
PIEZOELECTRIC SENSITIVITY MEASUREMENTS OF CELLULOSE NANOFIBRIL SENSORS

Piezoelectric sensitivity of cellulose nanofibril (CNF) film sensors was measured using a mechanical shaker and charge amplifier setup. In-house fabricated CNF film sensors showed 5-7 pC/N sensitivity in ambient conditions. The CNF film used here contained randomly oriented fibrils, and the piezoelectric response is expected to increase remarkably after film polarization and fibril alignment. The results obtained in this study suggest that nanocellulose film is a suitable sensor material for applications in various fields such as material sciences, electronics and biomedical diagnostics.

Emese Turzó-András
INFLUENCE OF THERMAL CONTACT RESISTANCE IN THERMAL CONDUCTIVITY MEASUREMENTS USING GUARDED HOT PLATE METHOD

A new technique was developed at the Hungarian Metrological Institute (MKEH), devoted to optimising the thermal conductivity measurements by quantifying and minimising the effect of the thermal contact resistance (TCR) arising between a rigid sample and the heated plate of a high temperature guarded hot plate. Due to the existence of the TCR, the calculated thermal conductivity, based on different measurement techniques, could differ with by as much as 5-9 %.
The work was performed in the frame of the European Metrology Research Program (EMRP SIB52) titled “Metrology for Thermal Protection Materials”.

J. C. Torres-Guzman, J. J. Galvan Mancilla
TORQUE METROLOGY IN MEXICO, TWENTY YEARS

The Physikalisch Technische Bundesanstalt - PTB in Germany was the pioneer of torque primary metrology, Dr. Diedert Peschel was the first torque laboratory Head. The Centro Nacional de Metrología in México, CENAM, began operations in 1994. The torque laboratory was installed in 1995 at CENAM. This paper presents the most important activities during the last two decades and the action plans for the coming years in torque metrology in Mexico.

Falk Tegtmeier, Michael Wagner, Rolf Kumme
INVESTIGATION OF TRANSFER STANDARDS IN THE HIGHEST RANGE UP TO 50 MN WITHIN EMRP PROJECT SIB 63

The EMRP SIB 63 project was established to give the end user the needed measurement technology, traceability and tools to work in the highest force range up to 50 MN. This paper describes work package WP1 which deals with BU systems as transfer standards. A knowledgebase was collected to optimize the design with complex studies and models. Within the project, also an uncertainty model and technical guidelines will be developed.

Ana-Maria Comănici, Petru-Marian Cârlescu, Paul-Doru Bârsănescu, Dan-Mihai Ştefănescu
STRAIN GAUGE ROSETTE FOR TRIAXIAL STRAIN MEASUREMENT

In this paper is presented a way to measure the triaxial state of strain and stress using strain gauge rosette for residual stress measurements and a sensitive pin with a small strain gauge glued on the plane surface of the cylinder. It is proposed an upgraded version of the biaxial state of stress measurement method verified by finite element analysis.

Corey Stambaugh, Edward Mulhern, Eric Benck, Zeina Kubarych, Patrick Abbott
PROGRESS ON MAGNETIC SUSPENSION FOR THE NIST VACUUM-TO-AIR MASS DISSEMINATION SYSTEM

The redefined kilogram will be realized in vacuum and NIST is developing a magnetic suspension system to disseminate the standard to air. This paper details the progress to characterize and improve the performance of the magnetic suspension portion of the system. Effort has been made to determine the magnetic field within the system through simulation and experiment. To increase stability interferometry is being integrated into the system.

Christian Schlegel, Gabriela Kiekenap, Rolf Kumme
UNCERTAINTY EVALUATION OF SINUSOIDAL FORCE MEASUREMENT

Periodical force measurement is used for the primary calibration of force transducers. This abstract describes models for an uncertainty determination of the sensitivity, which is the main measurand. Influences like the mechanical coupling of test masses as well as their rocking during a measurement are the dominating contributions to the uncertainty of measurement. The achievable uncertainties will be demonstrated on the basis of intercomparison periodical force measurements between CEM and PTB as well as the comparison between standard GUM and Monte Carlo based uncertainty evaluation.

Marco M. Schäck
UNDERESTIMATED IMPACT OF MEASURING CABLES ON HIGH-PRECISION CARRIER FREQUENCY AMPLIFIER RESULTS AND COMPENSATION METHODS THEREFOR

The resolution when acquiring transducer results is physically limited. To ensure accurate measurements of resistive transducers in full bridge circuitry, in addition to the amplifier's precision, the use of appropriate measuring cables and their proper connection are very important.
Sources of errors with respect to the used measurement cables and their compensation to achieve the high accuracy class are shown. If these principles are not observed, there will be inescapably significant errors.

Tassanai Sanponpute, Nittaya Arksonnarong, Andreas Brüge, Nattapon Saenkhum
SUSPENDED-FULCRUM TORQUE STANDARD MACHINE, 2ND REPORT

National Institute of Metrology (Thailand), NIMT has developed the suspended fulcrum torque standard machine. The mainly tasks are metal sheet for fulcrum and hung-weight changing. Moreover propose and investigate methods for the different lever arm length, Δl and the sensitivity of fulcrum. Experiment results that using different length of thin sheet metal besides, different evaluation techniques for Δl were compared. Sensitivity of fulcrum carried out whole measurement range was discussed. The comparison result between NIMT and PTB was expressed in term of degree of equivalence (En). It showed that comparison result was satisfactory.

Page 378 of 977 Results 3771 - 3780 of 9762