Jeah-Sheng Wu, Hsien-Chi Yeh, Sheau-shi Pan
MEASUREMENT OF PHOTON PRESSURE

Center for Measurement Standards has established a system to probe micro force down to nano Newton. Based on a very stable torsion strip pendulum with restoring torque constant 5.25·10^-6 N·m/rad. Light beam of a high power Nd:YAG laser was reflected by the mirror attached on pendulum frame. Result in angular deflection of the pendulum. The deflection was measured by an angular interferometer with resolution 1.95·10^-7 rad. Modulation signal, generated by varying power of laser, shift the pendulum from its standing position. The angular deflection equivalent torque is the same as photon generating torque to within 22%.

A.Capelli, G.D’Agostino, S.Desogus, A.Germak, C. Origlia, D. Quagliotti
A TRANSPORTABLE ABSOLUTE GRAVITY METER ADOPTING THE SYMMETRIC RISE AND FALLING METHOD

The Gravimetry Group of the Institute of Metrology “G. Colonnetti” (IMGC-CNR), nowadays National Institute of Research in Metrology (INRIM), developed a new version of a transportable absolute gravimeter, the IMGC-02. The instrument presents several improvements mainly concerning the transportability, the measurement automation and the user-interface programs. According to the ISO-GUM (Guide to the Expression of Uncertainty in Measurements), an extensive analysis concerning the contributors to the uncertainty budget has been conducted. At present the instrumental expanded uncertainty (p = 95%) is believed to be about 8 parts in 10⁹ of the surface gravity value. The detailed description of the IMGC-02 apparatus and an outline of its metrological characterization is the subject of this paper.

Dirk Röske, Dietmar Mauersberger
ON THE STABILITY OF MEASURING DEVICES FOR TORQUE KEY COMPARISONS

Key comparisons are an important approach for the national metrological institutes to ensure that the units of the different physical, chemical and other quantities are realized and disseminated according to the stated uncertainties. In May 2005, the first world-wide CIPM torque key comparison (CCM.T-K1) has been started. The main purpose of this paper is to compare the stability of the torque standard machine, the travelling standard (torque transfer standard) and the amplifier DMP40 of the pilot laboratory with the combination of the bridge standard BN100 and the same amplifier.

Barry Pratt, Andy Robinson
A COMPARISON BETWEEN SUPPORTED AND UNSUPPORTED BEAMS FOR USE IN STATIC TORQUE CALIBRATIONS

In industry, calibration beams are frequently coupled directly to the measurement transducer. This paper aims to quantify the effect of using such a method in contrast to the bearing supported case for a range of commercially available transducers.

Ricardo Luís da Rocha Carmona, Sílvio Fazolli, Milton Pereira
MENIR – A CONTRIBUTION FOR FINAL UNCERTANTY EVALUATION OF ROCKETS MASS MEASUREMENTS

The weight is a very significant property for several rocket projects’ calculations. The cost of satellite mass is very high and a reduction of 1% can save thousands of dollars. Then it’s necessary to know the most important uncertainty sources to obtain a reliable result. In this paper, a developed method is shown to find the smaller uncertainty of a rocket’s weight among several available weighing instrument parks.