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Page 907 of 914 Results 9061 - 9070 of 9134

Woo Gab Lee, Jin Wan Chung, Kwang Pyo Kim
SIGNIFICANCE OF ORTHOGONALITY IN MASS CALIBRATION

The designs for submultiples of the unit of mass have been studied to find designs where two comparators are used. This study has found several cases where orthogonal designs can be used for using two comparators in a decade. Even though the orthogonal designs are for the case where the ratio of the comparator’s standard deviation is 2, simulation showed extended values of the ratio could be used to reduce variances with the orthogonal designs.

Lim Chi Kah, Bernd Glöckner, Thomas Allgeier
NEW DEVELOPMENTS IN LEVER-AMPLIFIED FORCE STANDARD MACHINES

This paper describes the unique features and metrological performance of a new 55 kN / 2200 kN lever deadweight force standard machine set up recently at SPRING Singapore. It uses a novel 55 kN deadweight stack with individual mass disk drives, a single lever of 40 times multiplication ratio and a 2.2 MN tension-compression loading device. The machine is of increased capacity, with a wider force range and larger amplification ratio than previously possible. The lever machine covers force range from 10 kN up to 2200 kN in intervals of 10 kN. For the first time, a force standard machine of this type and size uses an entirely digital control system. The machine has been the subject of a comparison measurement with the PTB, preliminary results of which are given. The uncertainties of the machine were found to be within 2·10-5 for the deadweight part and 1·10-4 for the lever part. The system now serves as a primary force standard for Singapore.

Li Zhang, Rolf Kumme
INVESTIGATION OF INTERFEROMETRIC METHODS FOR DYNAMIC FORCE MEASUREMENT

Dynamic forces realised by accelerated load masses are traceable to acceleration and mass according to the force definition. For the reduction of the measurement uncertainty, the acceleration distribution of the acting mass has to be determined with higher accuracy. This is possible by using laser interferometer and suitable methods for signal processing and data analysis. In particular a method of using heterodyne laser interferometer for dynamic force calibration is investigated. Different signal processing and data analysing methods are compared. A force transducer is investigated with interferometric procedures and it is demonstrated that improvements are possible in dynamic force calibration by laser interferometer.

Takanori Yamazaki, Ryosuke Tasaki, Hideo Ohnishi, Masaaki Kobayashi, Shigeru Kurosu
ACCURACY FOR CONTINUOUS MASS MEASUREMENTS IN MULTI-STAGE BELT CONVEYORS

Large quantities of commodities in different sizes transported on belt conveyors should often be measured automatically by two or three conveyor belt scales. Continuous measurement can be dynamically performed by multi-stage conveyor belt scales, so that the masses of discrete objects on belt conveyors can be determined in sequence according to the different lengths. Belt conveyor scales usually have maximum capacities of less than 80kg and 130cm, and achieve measuring rates of 150 packages per minutes and more. The output signals from the multistage conveyor belt scales are always contaminated with noises due to vibrations of the conveyor and the object to be measured in motion. This measuring system consists of the three-stage conveyor belt scales with load-cells, and the photo-electro switches which detect the measuring lengths of the objects and distance between each object in sequence. The experimental results on the multi-stage conveyor belt scales suggest that the algorithms proposed in this paper are effective enough to practical applications.

Rolf Kumme
A NEW CALIBRATION FACILITY FOR DYNAMIC FORCES UP TO 10 kN

Dynamic forces realised by accelerated load masses are traceable to acceleration and mass according to the force definition. For the extension of the dynamic force range a new facility based on an electrodynamic shaker system is developed.

Baris Çal, Sinan Fank, Hakan Ö. Özbay, Ercan Pelit, Cihan Kuzu, Bülent Aydemir
3 MN HYDRAULIC TYPE BUILD-UP FORCE STANDARD MACHINE INSTALLED AT NATIONAL METROLOGY INSTITUTE (UME)

A new hydraulic type build up force standard machine with a 3 MN loading capacity both in tension and compression modes is installed in Force Measurment Laboratory of UME. The machine is designed and manufactured by ÖZMAK Manufacturing Company according to the technical specifications outlined by UME.
The performance test results show that relative measurement uncertainty of a new 3 MN build-up machine of UME is better than 4·10-4.

Kyung-Ho Chang, Yong-Jae Lee
VOLUME MEASUREMENT OF 1 kg WEIGHT BY HYDROSTATIC WEIGHING USING TWO ZERODUR DENSITY STANDARD SPHERES

The hydrostatic weighing apparatus using two zerodur density standard spheres is built, and the weight exchanger, which is composed of a weight pan with the shape of a conoid and the standard weights with a slot, is constructed. In addition, the temperature and density gradient of transfer liquid are precisely corrected according to the measuring position of the liquid container. As a result, the volume of 1 kg standard weight in a class E1 obtains 124,90388 cm³ at 20°C with a precision of 8.4·10-5 cm³ (0,67 ppm) by hydrostatic weighing, and the measurement uncertainty shows 3.0·10-4 cm³ (2,4 ppm) in a confidence level of 95% with coverage factor k = 2.

Luis O. Becerra, Luz Mª. Centeno
MEXICAN DENSITY STANDARD: DATA TREATMENT IN HYDROSTATIC WEIGHING

The Mexican Density Standard is starting operation as a national reference. In the present paper, it is presented the data analysis in hydrostatic weighing, the uncertainty estimation and its validation by Monte Carlo’s Method of the transfer of accuracy of the National Density Standard of Mexico.

Richard Davis
MAGNETIZATION OF MASS STANDARDS AS DETERMINED BY GAUSSMETERS, MAGNETOMETERS AND SUSCEPTOMETERS

Magnetization of a mass standard can lead to weighing errors. This is because most modern balances are sources of non-uniform magnetic induction. Although the problem of unwanted magnetic forces is well known, the characterization of the magnetic properties of mass standards and balances can be problematic. This paper compares the kind of information that can be obtained from three types of instruments: Hall-probe gaussmeter, fluxgate magnetometer and susceptometer.

Thomas Bruns
SINUSOIDAL TORQUE CALIBRATION: A DESIGN FOR TRACEABILITY IN DYNAMIC TORQUE CALIBRATION

This paper is concerned with the problem of dynamic torque calibration. It presents the concept of a new calibration device designed at PTB, to provide traceability for dynamic calibration with sinusoidal torque. Furthermore some details of the measurement system, construction and data analysis will be discussed.

Page 907 of 914 Results 9061 - 9070 of 9134