## IMEKO Event Proceedings Search

Page 851 of 907 Results 8501 - 8510 of 9067

**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%.

**INVESTIGATION OF FORCE TRANSDUCERS WITH DIFFERENT LOADING PROCEDURES ON JOCKEY-WEIGHT AND DEADWEIGHT MACHINES**

Force transducers used as transfer standards are usually calibrated according to ISO 376. Industrially applied force transducers can be calibrated according to more simplified procedures, however with extended measurement uncertainty. The main purpose of this paper is to point out the different values of the characteristic parameters which are due to varied loading procedures.

**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 10^{9} 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.

**NEW CONCEPT OF FORCE REALIZATION BASED ON MACROSCOPIC QUANTUM EFFECT**

We present a new concept of force realization, flux quantum-based mechanism in the sub-pico-Newton range. By controlling the number of flux quantum in a superconducting ring, a force can be generated as an integer multiple of a constant force step. For a 50 nm-thick Nb annulus with the inner and outer radii of 5 µm and 10 µm, respectively, and the field gradient of 10 T/m the force step is estimated to be 184 fN. Realization procedure, feasibility, and the stability against thermal fluctuations are also addressed.

**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.

**DENSITY MEASUREMENT OF A THIN-FILM BY THE PRESSURE-OF-FLOTATION METHOD**

A method for density and thickness measurements of a thin-film is described by the pressure-offlotation method (PFM). The density and thickness of a silicon thermal oxide layer on silicon crystal are determined by measuring the density and mass differences for the sample with and without the thin-film. Details on the density and thickness measurement and the results of the measurements are presented.

**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.

**DYNAMIC EVALUATION OF COLUMN TYPE MULTI-COMPONENT FORCE TRANSDUCERS**

This paper describes the dynamic characteristics of column type 6-component force-moment sensors with force components Fx, Fy, Fz and moment components Mx, My, Mz. We have evaluated the dynamic characteristics of the force-moment sensors by using a shaker system and a multi-channel dynamic analyzer system. It reveals that the sensitivity decreases as the frequency increases except for the Fz component and that the sensor shows almost 90° symmetry due to its geometry.

**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.

**EVALUATING THE UNCERTAINTY FOR MAGNETIC SUSCEPTIBILITY USING THE DIRECTLY METHOD**

The volume magnetic susceptometer was established in the CMS mass laboratory in 2003. The method is referred to the experimental method and procedure developed by Davis; while the distances between weighs and the magnetic sample were measured with the laser interferometer. We calculated the effect by the offset between the magnetic source and the weights; then we evaluated the uncertainty of the *χ*-value in samples directly.

Page 851 of 907 Results 8501 - 8510 of 9067