IMEKO Event Proceedings

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Abstract
Event

Sohair Fakhry
Role of the national institute of standards (NIS) in the development of nation
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Leo Van Biesen, Tamás Kemény, Dirk Röske
NON-GOVERNMENTAL COOPERATION IN MEASUREMENT
IMEKO is a non-governmental federation of 35 national Member Organisations, individually concerned with the advancement of measurement technology and instrument engineering. The Member Organisations are scientific/technical societies or committees. The membership consists of the representatives of metrological institutions, higher education, industry and the users of instruments. The paper deals with the objectives of the Confederation, informs on the structure and financial background, on IMEKO publications and on the activities of 20 Technical Committees. Finally the future World Congresses, different scientific services, membership development, events and co-sponsorships are discussed.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Tamás Kemény
TC 3 – FROM THE BIRTH TO WORLDWIDE RECOGNITION
IMEKO TC 3 after 37 years of its founding organises the 19th Conference in Cairo, 2005. The paper gives a survey of the first 16 years, reporting the first 10 Conferences and round table discussions. The most important personalities are mentioned with the development of the field as well. This heroic period was a firm base of the next 20 years and of the future activities.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

D. Peschel, D. Mauersberger, D. Schwind, U. Kolwinski
THE NEW 1.1 MN·m TORQUE STANDARD MACHINE OF THE PTB BRAUNSCHWEIG/GERMANY
Until 2003 it was impossible to perform traceable calibrations for torque measuring systems above applied torque values of 200 kN·m anywhere in the world. Up to this figure such calibrations are possible at LNE/Paris. This is despite the fact that a number of applications with considerably larger torque values are known (energy generation, shipbuilding etc.). In addition there are requests for calibrations above the largest measuring range so far available at the PTB (20 kN·m), as realised with a deadweight torque standard machine (20 kN·m TSM) acting on a double-sided lever arm supported in an air bearing. In 2002/2003, a new torque standard machine with a capacity of 1.1 MN·m was constructed and manufactured by GTM Gassmann Theiss Messtechnik GmbH in co-operation with the torque laboratory of the PTB. In 2004, initial evaluations and the analysis of the measurement uncertainty were concluded. First calibrations were already performed in May/June 2004. The machine has a vertical test axis and the effective torque is determined by means of force transducers acting on a double-sided lever arm. Parasitic bending moments and transverse forces, which cannot be entirely avoided, at the locations of the force transducers are measured by strain-gauged bending joints. These disturbances are partly controlled by additional drives and partly electronically processed to correct the measuring signal. This allows to abandon the principle so far applied – i.e. the reduction of parasitic quantities by use of metallic multiple disk couplings which are torsionally stiff and flexible in bending – and to rigidly couple the object to be calibrated. Measurement of the mechanical parasitic quantities during loading and reducing them to a negligible amount with respect to the measurement uncertainty allows the system to be used as national standard with sufficiently small uncertainty of measurement. The aim is to achieve a value of 0.1 % (k = 2) in the measuring range from 5 kN·m to 1100 kN·m. There are further requirements which call for a reduction of the measurement uncertainty in the measurement range up to 100 kN·m which will be dealt with in future. The paper gives an overview of the design, construction and first results of the investigations into the measurement uncertainty.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Richard Davis
NEW WAYS TO DETERMINE VERY SMALL MASSES AND FORCES
The goal of this paper is to draw attention to mass determinations at nominal values well below 1 µg. Traceability to the International System of Units (SI) is challenging because mass standards having nominal values less than 1 mg are difficult to produce and thus not commonly available. We limit this burgeoning subject to only three examples: the calibration of atomic force microscopes with respect to calibrated dead-weights; the confirmation that a NEMS device has attogram resolution; and the direct determination of the gravitational mass of the neutron. We do not mention the important topic of magnetic resonance force microscopy because the applications to mass measurement are less direct than in the examples that have been chosen.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Michael Gläser
The unit kilogram, needs and experiments for a new definition
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

David Kimetto
CALIBRATION PROCEDURE OF MATERIAL TESTING MACHINES IN KENYA
This paper highlights how the S.I unit of force (Newton) is realized in the Kenya Bureau Of Standards force laboratory. The use of the 1MN Multi-Lever Force Standard Machine. The dissemination of the Unit (N) in the organization (KEBS) and in the Kenyan industry. Calculation of uncertainty of measurement.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Ryosuke Tasaki, Takanori Yamazaki, Hideo Ohnishi, Masaaki Kobayashi, Shigeru Kurosu
CONTINUOUS WEIGHING ON A CONVEYOR BELT WITH FIR FILTER
Today much higher speed of operation and highly accurate weighing of packages during crossing a conveyor belt has been getting more and more important in the food and distribution industries etc. Continuous weighing means that masses of discrete packages on a conveyor belt are automatically determined in sequence. Making the best use of new weighing scale called a multi-stage conveyor belt scale which can be created so as to adjust the conveyor belt length to the product length, we propose a simplified and effective mass estimation algorithm under practical vibration modes. Conveyor belt scales usually have maximum capacities of less than 80 kg and 140 cm, and achieve measuring rates of 150 packages per minute and more. The output signals from the conveyor belt scales are always contaminated with noises due to vibrations of the conveyor belt and the product in motion. In this paper an employed digital filter is of Finite-duration Impulse Response (FIR) type designed under the consideration on the dynamics of conveyor belt scales. The experimental results on conveyor belt scales suggest that the filtering algorithm proposed here is effective enough to practical applications.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Sevda KAÇMAZ, Haldun DIZDAR
AUTOMATIC TURNTABLE DESIGN FOR 500 kg BALANCE
An automatic turntable system was designed for 500 kg mass comparator. The turntable system was constructed in one piece due to dimensional stability and calibration of cylindrical also rectangular shaped weights between 100 kg and 500 kg weights. This system is controlled by PLC, optionally it is possible to use manually.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Levent Yagmur, Sevda Kacmaz
ENDURANCE TESTING MACHINE FOR NONAUTOMATIC WEIGHING INSTRUMENTS
A machine was designed and manufactured for endurance tests of nonautomatic weighing instruments according to the regulation of OIML R76-1-2 and EEC/90/384. An AC servomotor directly actuates the machine. It has also control panel and software. It has a compact module consisting of ball screw mechanism and a handler, made of polyamide material, specially designed. It is used for handling nine numbers of standard masses, knops headed type, with ranges 100 g up to 50 kg. There are nine types of weight carriers for each different mass. Some parameters for loading and unloading of masses can be set to desired values within limits by using control panel. The velocities of loading and unloading of masses and also standing time of mass on the instrument can be adjusted. All parts of movable section of the machine were enclosed by using plexiglas material for preventing. The machine is capable of 100.000 and more times fully automatically loading and unloading of 9 (nine) types of standard masses on to the instrument. It can also be modified to another standard masses not in range 100 g to 50 kg.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Lenara KANGI, Sevda KAÇMAZ, Levent YAGMUR
PERFORMANCE TEST RESULTS OF THE UME “M ONE” MASS COMPARATOR IN AIR AND UNDER VACUUM ENVIRONMENTS
The UME “M One” mass comparator system was installed at the UME to be used research activities in describing an optimum transfer standard as buoyancy artifacts and comparing buoyancy artifacts between in air and vacuum environments and also 1 kg mass standards. The system were designed and manufactured by Mettler Toledo. The reproducibility of the mass comparator is 0,4 µg under vacuum.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Sinan Fank
INFLUENCE OF MICROSTRUCTURAL CHANGE IN AISI 4340 STEEL SPRING MATERIAL HAVING IDENTICAL HARDNESS LEVEL ON THE HYSTERESIS ERROR OF FORCE TRANSDUCER
Different heat treatment processes can be applied on the spring element of a force transducer in order to obtain good and satisfactory performance. The manufacturers are generally focused on the improvement of performance by applying different heat treatments on spring material, and no information is in free circulation regarding the process-performance relationships of transducers due to tight competition in the market. The study covers the attempts of different heat treatments on spring element using AISI 4340, which is regarded as one of the best spring materials for force transducer applications. The steel was quenched and tempered at predetermined temperature, and 45 Rockwell-C hardness values was reached to obtain fine martensite structure. In order to obtain coarse martensite structure having identical hardness from spring material, some specimens were subjected to high temperature during austenite transformation in 1000°C in 4.5 hours priority. In order to produce bainitic structure different heat treatment was applied on the specimens to have identical hardness level. It was observed that different heat treatments influenced the transducer performance, particularly hysteresis behaviour point of view. To minimize the hysteresis error of force transducers has prime concern and best result was obtained in the bainitic- structured specimen. After building the force transducers with differently heat-treated spring materials, their performances were recorded by using a dead weight force standard machine, concentrating on hysteresis characteristics. The results were compared with each other and analysed regarding the structural properties of spring materials and a process path was proposed to obtain the best performance in force transducers.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Baris Cal, Bulent Aydemir, Sinan Fank
EFFECT OF TEST SPEED ON VERIFICATION OF MATERIAL TESTING MACHINE
In order to verify material testing machine, constant test speed is necessary for satisfactory results. According to EN 10002-2 or EN ISO 7500-1 standards, all the verifications shall be carried out with a slowly increasing force. This means that test speed should be low as much as possible. But it is not specified in the standards. If the machine is capable to hold the selected force in quasi-static conditions, in this case selected forces are applied step by step during verification. In some cases, material testing machine cannot capable to hold quasi-static force. In this case, it causes the error due to difficulty of reading and getting the data. Sometimes, machine cannot adjust the slow test speed; in this case results are doubtful. In this study, measurements were realized in tension testing machine using force-proving instruments, which comply with the requirements specified in EN ISO 376 and EN 10002-3. The class of the instrument is 00 as well. Similar measurements were repeated during different test speed conditions to compare results and determine the effect of test speed on the verification results. At the same time, step- by-step and continuously increasing forces during identical test speed condition are compared to determine the effect of loading conditions. Measurement results show that different test speed and loading conditions during verification of material testing machine effect the verification results. In this study these results are discussed and findings are presented.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

V. Tsymbalyuk, J. Linhart
CORRECTIONS OF AERODYNAMIC LOADINGS MEASUREMENT ON AIRFOIL CASCADE AT BENDING-TORSION VIBRATIONS
The paper describes improvement of the unsteady aerodynamic forces and moments measurements in an airfoil cascade. These loads are caused by shifting and angular vibrations of airfoils. The improvement was achieved by taking airfoils and other elements deformations, induced by action of innercia and measured aerodynamic firces, in consideration during the calibration and measurement process. The different variants of airfoils supporting are considered.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Philippe Averlant
STRAIN CYLINDERS FOR COMPRESSION TESTING MACHINES
Measurement results of the compressive strength of concrete specimens depend on the manner of force transfer by the testing machine. This performance is verified according to a standard using strain cylinders. However, the qualification or calibration of strain cylinders is not defined in the standard. This paper presents a new procedure for cylinder calibration. The measurand is defined. The standard quantity is modelised depending on the specific manner of loading during calibration. Uncertainties are computed using theoretical equations. The results of a first cylinder calibration are given.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Thomas Bruns, Michael Kobusch
DATA ACQUISITION AND PROCESSING FOR PTB'S IMPACT FORCE STANDARD MACHINE
The 20 kN Impact Force Standard Machine (IFSM) of PTB’s working group “Impact Dynamics” is supposed to provide traceability for dynamic force by measuring the acceleration of a steel body using a laser-Doppler-interferometer (LDI) [1]. The acceleration itself is derived from time dependant velocity data by numerical differentiation, which is a process prone to noise amplification. Therefore a thorough investigation of the data flow and data analysis algorithms concerning robustness, accuracy and the proliferation of disturbances is necessary. This paper describes the data acquisition system together with three different algorithms for digital demodulation of the LDI signal with regard to the boundary conditions given by the parameters of the equipment.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Michael Borys, Michael Gläser, Michael Mecke
MASS DETERMINATION OF SILICON SPHERES USED FOR THE AVOGADRO PROJECT
Spheres made of a silicon single crystal with a mass of about 1 kg are used as density standards and in the context of a project for the determination of the Avogadro constant. The status of the mass determination of such silicon spheres at the PTB is presented. Special facilities and procedures used for the mass determination in air are described. Results for a single sphere and the mass difference between two spheres are given with a discussion of the measurement uncertainty and mass stability.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Bruno Andò, Pietro Giannone, Salvatore Graziani, Nicola Pitrone
MEASUREMENT SYSTEM FOR THE CHARACTERIZATION OF PIEZOELECTRIC BIMORPHS
Hysteresis is a common phenomenon in various non linear systems including piezoceramic materials. Piezoelectric bimorph devices show hysteretic behaviour, when operating as actuators. In this paper an experimental set-up to investigate the hysteretic behaviour of a PZT is described. The strategy adopted uses a resistive readout scheme and a CCD tool for the system calibration. Moreover, software tools have been developed to manage the experimental and to process signals coming from the hardware developed.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

C. Ferrero, C. Marinari, E. Vilalta
APPLUS+ AND IMGC DEADWEIGHT FORCE MACHINES INTERCOMPARISON BY USING THE IMGC SIX-COMPONENT DYNAMOMETERS
Two IMGC multicomponent dynamometers were used to measure the parasitic components generated by the APPLUS+ 0,5 MN deadweight force standard machine. Results are presented which indicate that they are of a very low level. Measurements of the dynamic components during weight changes and free suspension of the system are also presented.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

N.G. Domostroeva, A.V. Domostroev
PROBLEMS CRUDE OIL WEIGHT CALCULATION
This report describes problems of crude oil weight measurement in the tanks. The results of the crude oil density and temperature measurement are presented, obtained with the different method of sampling. The uncertainty budget in measuring the crude oil weight is given.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Chi Kah Lim, Bernd Glöckner, Thomas Allgeier
SHORT AND LONG-TERM BEHAVIOUR OF A 55 kN / 2.2 MN LEVER DEADWEIGHT FORCE STANDARD MACHINE
This paper describes the latest results from the re-verification of a 55 kN / 2.2 MN lever deadweight force standard machine at SPRING Singapore. For the first time, a lever machine was successfully compared against deadweight machines (from PTB) at the high level of 2 MN in both tension and compression with an uncertainty in the 1E-4 range. Similarly, the same applies to the 55 kN machine with an uncertainty of ±2E-5. For the 55 kN machine, both short-term and long-term uncertainty has been established. The machine had been the subject of an earlier comparison measurement with the PTB in the compression range. In addition, the periodic maintenance results of this 55 kN / 2.2 MN lever deadweight force standard machine will also be discussed. To monitor the drift and stability of the force realised, a total of 5 SPRING FTS were measured according to fixed protocols over time. The lever amplification ratio was also checked at intervals using a 50 kN FTS. From an earlier maintenance check, it was discovered that there was a significant drift in the lever ratio in March 2003 (12 months after commissioning). However, the deadweight forces continued to be realised within the ±2E-5 uncertainty. The lever ratio has since been adjusted back to producing loads which are magnified exactly 40 times from deadweight forces, demonstrating that it is capable of achieving ±1E-4 short term uncertainty. This was confirmed by the comparison with PTB up to 2 MN in both loading directions. Subsequent measurements demonstrated that the lever ratio has been stable. The same is also true for load reproducibility and repeatability at both the deadweight and lever machine, indicating that the long- term uncertainty is now satisfactory as well.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Sheau-shi Pan, H. C. Lu, C. S. Chang
INSTRUMENTS USED FOR MEASURING THE MAGNETIC PROPERTIES OF ONE KILOGRAM MASS STANDARD IN CENTER FOR MEASUREMENT STANDARDS (CMS)
We measured the volume magnetic susceptibility and permanent magnetization of 1 kg mass standards are measured under the circumstances of CMS mass laboratory. The method and calculation of uncertainty described here are referred to the experimental method and procedure developed by Davis; while the distance between magnetic sample and the weighs were measured with aluminium guide and the distance was determined by reading of laser interferometer. The effects of volume magnetic susceptibility and permanent magnetization on weights was real-time measured .The degree of real-time measured dependent upon the transient time of the balance. These results of susceptibility measurement were compared to the results of samples when they arrived CMS.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Michael Kobusch, Thomas Bruns, Lioba Stenner, Sven-Patrick Schotte
IMPULSE FORCE INVESTIGATIONS OF STRAIN GAUGE SENSORS
This paper presents new investigations of strain gauge force sensors subject to impulse loads. Different approaches regarding the determination of the fundamental axial resonance are discussed in order to get information about a practical evaluation method for common-type strain gauge sensors under dynamic loads.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

K. Fukuda, K. Yoshida, T. Ono, K. Kameoka, T. Hirata
AN ADVANCED ALGORITHM FOR ESTIMATING AXLE WEIGHTS OF IN-MOTION VEHICLES
A signal processing method to improve the accuracy of measured axle weights of an in-motion vehicle is proposed and is evaluated by applying it to the actual weight signals from a new axle weighing system with a platform having a length of about 2.2m, approximately three times longer than that of a conventional one. In spite of several undesirable experimental conditions, the accuracy improvement was confirmed within the range of vehicle velocity, 5 ~ 40km/h.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Thomas Fröhlich, Thomas Fehling, Benno Gatzemeier, Detlef Heydenbluth
SARTORIUS SUSCEPTOMETER FOR PRECISE MEASUREMENT OF SUSCEPTIBILITY AND MAGNETIZATION OF WEIGHTS
The Sartorius Susceptometer is a commercially available susceptometer as described in the Draft revision of International Recommendation OIML R111. It comes with a calibration sheet. The procedure of the factory calibration is described. A measurement comparing five calibrated susceptibility standards is discussed. The magnets used for calibration are monitored concerning the stability of the magnetic dipole moment over about one year.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

S. Niehe
NEW EXPERIENCES WITH A FORCE MEASURING FACILITY FROM THE RANGE FROM 1 mN TO 5 N
In this contribution new experiences with a force measuring facility [1] for the range from 1 mN to 5 N consisting of a piezoelectric positioning unit for force generation and a precision compensation balance for force measuring are presented. The enhancement of the facility by means of a rotational table allows to rotate the force transducer under test around its axis and to measure the sensitivity of the transducer at different positions. By averaging the measured sensitivities of a complete rotation cycle the rotation effect can be taken into account and the deviation from the calibration of the investigated force transducer in a deadweight force standard machine is then of the order of 10^-4 in relative terms. This improves the deviation of earlier results [1] without consideration of rotation effects about a factor of 8.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. S. Kim, I. M. Choi, Y. K. Park, D.I. Kang
ATOMIC FORCE MICROSCOPE PROBE CALIBRATION BY USE OF A COMMERCIAL PRECISION BALANCE
In this paper, we investigate the characteristics of commercial AFM cantilevers and force calibration cantilevers in the range of 10 nN ~ 1000 µN by use of a high precision balance with resolution of 1 nN and 1-D fine positioning stage. This document is a guideline to the authors of papers to be presented at the TC3 2005 conference. These directions are written in the format required for papers. We advise you to download these directions as a MS Word document and use it as the template for your paper because it contains all necessary formats and styles. Papers should be submitted before October 30, 2004. The paper must be written in English, and length is limited to 6 pages, including graphs, figures, reference list.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

J. W. Chung, M. Borys, M. Firlus, W. G. Lee, R. Schwartz
BILATERAL COMPARISON OF BUOYANCY ARTEFACTS BETWEEN PTB AND KRISS
Buoyancy artefacts (BAs) are used for the experimental determination of air density. The artefacts used for this comparison were manufactured at the PTB and the KRISS respectively and consist of one hollow cylinder and one bobbin. Mass differences of the PTB and the KRISS BAs in vacuum and in air are measured simultaneously by using the PTB prototype mass comparator. Results of the bilateral comparison including uncertainty budgets and the deviation between air densities obtained by the BAs and those calculated by the CIPM formula are presented. Additionally, a comparison with a correction of the CIPM formula based on recently measured values for the air composition is given.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Oliver Mack
INVESTIGATIONS OF PIEZOELECTRIC FORCE MEASURING DEVICES FOR USE IN LEGAL WEIGHING METROLOGY
In conjunction with low-drift charge amplifiers static force and weighing measurements get more and more important for piezoelectric force transducers if the measuring time and time of load change are in the range of a few minutes. The presented investigations according to the international recommendation OIML R60 [7] point out, that piezoelectric sensors can be used for static applications with low accuracy requirements (e.g. class D for ordinary accuracy weighing instruments). With suitable methods for compensation or adjustment the sensors even meet the higher requirements of medium accuracy class C (e.g. commercial scales). Especially for high nominal loads the piezoelectric measurement technology offer unused potentials also for static precision measurements.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Richard Davis, Josette Coarasa
ERRORS DUE TO MAGNETIC EFFECTS IN 1 kg PRIMARY MASS COMPARATORS
A revised draft of OIML R111 has been approved recently. Among the many notable changes to the previous edition are specific requirements for both the magnetic susceptibility and residual magnetization of weights used in legal metrology. The highest class of such weights is E1, for which a 1 kg weight has a manufacturing tolerance of ± 0.5 mg. It therefore follows that better magnetic properties might be needed for weights having mass uncertainties substantially better than E1 tolerances. The work presented below shows how this problem was approached at the BIPM and supports our conclusion that alloys meeting the new Class E1 specifications for 1 kg weights have magnetic properties sufficient for the needs of the BIPM.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

F. Tegtmeier, M. Peters
ENCAPSULATION AND UNCERTAINTIES OF STRAIN-GAUGE SENSORS FOR STRESS-MONITORING OF CONSTRUCTIONS
Strain gauges are an important tool in measuring techniques applied to determine loads and detect damages. Due to their high signal-resolving power, they are also suitable for stress analysis in building constructions. Without specific encapsulation, they are, however, suitable only for short-term measurements. Therefore, a completely new encapsulation type was developed at PTB. The strain gauges were placed in a sensor housing which protects the sensitive technology - similar to common force transducers - and is fitted into a small measurement borehole of the structure. These applied investigations were part of the work of a collaborative research center of the German Research Foundation. Based on these investigations, the measurement uncertainty of the sensor will be analyzed and the final design for commercial production and calibration of this new sensor type presented. An additional impor- tant result of this research project was the development of a new type of plastic encapsulation for the strain gauges inside that sensor. The encapsulation was tested in thermostatic hot water baths, in climatic chambers similar to those of DIN IEC 68 2-30 and in outdoor tests.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Dan-Mihai Stefanescu, Dae-Im Kang
AXISYMMETRICAL ELASTIC ELEMENTS FOR VERY LARGE FORCE TRANSDUCERS
Measuring of large forces up to 10 MN with high accuracy is a complex subject, blending theory, practice and applications, with a special accent in the field of Metrology. It is simply to generate complex shapes of mono-block elastic structures starting from simple shapes of strain gage measuring sections, the axisymmetrical ones being the best suited in this respect. The body of the force transducer is easy to design by 2D axisymmetric FEM and easy to manufacture. The paper have in view a unified approach of square (type A) and rectangle (type B). Square section is among the few with an analytical but complicated formula, having two strain gauges tangentially located on the outside of the ring torsion and the other two strain gauges, which complete the Wheatstone bridge, being diametrically opposed. The rectangular section (with different ratios between the two sides but without analytical formula), is obtained by a minimum modification of the previous one (making two slots), the strain gauges being circumferentially located on the upper and the lower faces. We formulate a standard FEA procedure for axisymmetrical elastic elements of strain gauged force transducers using ANSYS Mechanical program. The starting model is very “flexible”, so that, changing one by one different parameters (e.g. modifying the keypoints coordinates), a lot of variants could be studied. A special attention is necessary to obtain proper strain diagrams on the superior, lateral and inferior sides of the elastic element measuring section, because it is essential to compare these diagrams in order to establish the best strain gauges positioning. In this respect, appropriate paths were conceived and plotted each time on graph, more precise and suggestive than plotting on geometry. An original grouping of all kinds of strain diagrams on the same plot of the deformed and undeformed bodies is presented. A lot of interpretations are possible based on the multitude of data and having in view: the influence of the axisymmetrical elastic element shape (varying different parameters) on the strain gauge sensitivity; the best combination of conflicting design criteria: strain, stress (determining the overload) and displacement (determining the stiffness); the possible correlation between the nominal load and the dimensions of a particular variant, e.g. with square measuring section. In the next stages will be very useful to unite FEM and CAD, following the elastic elements parametric modeling for their best constructive optimization.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Aimo Pusa, Dirk Röske, Michael Sachs
COMPARISON MEASUREMENTS OF MIKES-RAUTE 20 kN·m TORQUE REFERENCE DEVICE WITH THE PTB
This article deals with the vertical 20 kN·m torque reference calibration device newly built by MIKES- RAUTE. It widens the possibilities of the MIKES-RAUTE Mass and Force Laboratory in the field of torque calibrations from 2 kN·m up to 20 kN·m. A brief overview about the construction and setup of the device is included in this report. Also some information about the applied calibration process is given. The main part of this article describes comparison measurements with the PTB, Germany, from summer 2004 and presents their results. They show that the device will attain an uncertainty level of 5·10^-4 or better over the entire measurement range.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Andreas Brüge, Rudolf Konya
INVESTIGATIONS ON TRANSDUCERS FOR TRANSFER OR REFERENCE IN CONTINUOUS TORQUE CALIBRATION
The highest level of torque calibration is achieved by direct loading and, due to the use of mass stacks, is associated with the step-by-step method. In order to fit the demand of applications especially in industry, calibration devices with the ability of performing continuous loading were developed which are working as reference machines. A benefit of continuous methods is that the time for a loading-unloading cycle can be ten times or more shorter than using the step method. This fast change in torque leads to conditions of use that cannot be represented in the national torque standards. Therefore the appointed reference- and transfer-transducers should have negligible sensitivity to fast loading effects. With such transducers the results of slow absolute calibrations in the national torque standards are valid also in the fast continuous-working machines. In Germany a guideline treating this problems of continuous calibration is in preparation at a working group of the German Calibration Service (DKD). In this guideline special qualification-tests are proposed which can be performed in existing direct loading machines and which can deliver information about the suitability of transducers as reference or transfer for continuous working machines. In this paper we describe these qualification-tests, discuss the results of the tests in comparison to the behaviour of the tested transducers in continuous measurements and recommendations for the selection of transducers for continuous use are given.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Dirk Röske
KEY COMPARISONS IN THE FIELD OF TORQUE MEASUREMENT
One of the main tasks of the National Metrology Institutes (NMIs), besides the realization and improvement of standards for the different physical and other quantities, is to carry out comparisons between their own standards and those of other NMIs. At the highest level, the CIPM key comparisons involve at least the standards with the smallest uncertainties of measurement in the world and should cover - if possible - all geographical regions through the corresponding Regional Metrological Organizations (RMOs). It is also intended to compare different realization techniques of the given quantity and to make a statement of equivalence for the different calibration capabilities. This document deals with the recently agreed CIPM key comparisons in the field of torque measurement.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Adrian Gherasimov, Eugen Ghita
THE UNCERTAINTY OF MEASUREMENT IN CALIBRATION USING A COMPARISON FORCE STANDARD MACHINE
The paper presents a practical example for the evaluation of the uncertainty in calibration using a comparison force standard machine with a maximum load of 1000 kN, tension and compression mode. The uncertainty of measurement associated with the input estimates is evaluated. It is also presented a way to minimize the uncertainty of the applied force with the view to attaining the necessary value for the calibration of class 1 force transducers, in accordance with ISO 376:1999. For this purpose an evaluation of the loading regime of the force machine is presented. There was identified the main input components influencing the uncertainty in calibrations, such as the force stability during measurements and the metrological characteristics of the reference transducers. Further are presented the practical results of the investigation of the force comparison machine after the optimization, including the technical and economical benefits.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Adrian Gherasimov, Eugen Ghita
THE TRACEABILITY SYSTEM OF FORCE MEASUREMENTS IN ROMANIA
The paper presents some technical aspects about the Romanian system built-up to ensure the traceability of force measurements to the SI units. The regulations of the traceability schemes and the steps to be followed are presented. The Force Laboratory Timisoara, pending of Romanian Bureau of Legal Metrology proposed and implemented the national traceability of force measurements. The paper presents the best measurements capabilities, which the Romanian calibration laboratories offer for force measurements. In order to perform a national and international validation of the force measurements in Romania, the traceability system must be in accordance with the national and international standards. One of the major parameters of the traceability system is the uncertainty associated with calibration or measurement results. This trend is based on the explosive implementation of the ISO 9000 series and ISO 17025 requirements in industry and other fields. The Romanian Government putted forward some regulations in order to provide for the necessary conditions to report the results to the acknowledged standards.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. Oblak, M. Grum, M. Terlep
MAGNETIC PROPERTIES OF OIML SHAPED WEIGHTS
The work presents an improved approach to the determination of magnetic properties of weights, which have a shape according to OIML R111. The main stress is laid on a measurement of the volume magnetic susceptibility and an evaluation of its uncertainty. The method is presented, how the volume magnetic susceptibility of the OIML weight can be determined taking into account an actual shape of the weight instead of using only an approximation of its shape with "outer" and "inner" cylinders. Monte Carlo simulation was used to evaluate the measurement uncertainty. The susceptibility of 1 kg weight was calculated by the method of "outer" and "inner" cylinders and the method presented in the article. Results of both methods are compared and discussed.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. Grum, M. Terlep, M. Oblak, L. Miklavcic
THE DETERMINATION OF GRAVITY ZONE FOR WEIGHING INSTRUMENTS IN SLOVENIA
Several derivations from the WELMEC gravity concept concerning non-automatic weighing instruments that are sensitive to the gravity were developed and analyzed. Apart from that, the gravity field model was developed for a territory of the Republic of Slovenia based on the geographical data and empirical gravity formula. It was established that some simplifications comparing to the WELMEC gravity zone concept could be introduced regarding free movement of weighing instruments across Slovenia. Limitations were set up concerning instruments’ characteristics that have to be regarded when the simplifications are used.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Koji Ohgushi, Takashi Ota, Kazunaga Ueda
UNCERTAINTY EVALUATION OF THE 20 kN·m DEADWEIGHT TORQUE STANDARD MACHINE
A deadweight-type torque standard machine of 20 kN·m rated capacity (20 kN·m-DWTSM) has been designed and developed by the National Metrology Institute of Japan (NMIJ) at the National Institute of Advanced Industrial Science and Technology (AIST). Each uncertainty contribution comes mainly from the performance of each mechanical part of the 20 kN·m-DWTSM. Authors evaluated the uncertainty of the mass of the linkage weights, local acceleration of gravity, influence of air buoyancy on deadweight loading, initial moment-arm length (including CMM measurement and temperature compensation), and sensitivity of the fulcrum. This report deals especially with evaluation of the remaining contributions, namely the influence of arm flexure and reference line variation at the end of the moment-arm on best measurement capability (BMC). Estimation of BMC in the 20 kN·m-DWTSM gave a relative expanded uncertainty of less than 7.0 × 10^-5 (k = 2) for the calibration range from 200 N·m to 20 kN·m.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

In-Mook Choi, Jong-Ho Kim, Hyo-Jik Lee, Min-Seok Kim, Yeon-Kyu Park, Sam-Yong Woo, Dae-Im Kang
DEVELOPMENT OF ELECTROMAGNETIC PROBE FOR MICRO FORCE MEAUSREMNT
Micro/Nano force measurement is becoming more essential in the fields of AFM metrology, biomedical industries, chemical industries, and material science. For the micro/nano force measurement, a cantilever mounted with Ni/Cr conducting wire has been fabricated by MEMS process. The cantilever with high sensitivity can be driven by Lorentz force which is generated by applying current into the wire under uniform magnetic flux. In order to measure micro/nano force precisely, the cantilever is controlled to a null position with the Lorentz force opposing to a vertical input force. The active measurement method by null balance is more accurate and sensitive than passive measurement method using a piezoresistive cantilever. For this measurement, the simple electromagnetic circuit is analyzed and constructed to obtain high magnetic flux density, and a spring constant for high force sensitivity and a resonant frequency for the stable control of the cantilever are analyzed by FEA. After the construction of a system with a displacement sensor and a controller, the basic measurement characteristics such as a resolution, linearity, and repeatability, will be determined by experiment, and the comparison calibration with a commercial cantilever will be carried out. This electromagnetic active probe can be used as a transfer standard for the micro force evaluation and dissemination. It would also be applicable to various researches and industries, such as binding-force measurement between molecules, force lithography, and nanoindentation.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

T. Yan, B. E. Jones, R. T. Rakowski, M. J. Tudor, S. P. Beeby, N. M. White
STIFF TORQUE TRANSDUCER WITH HIGH OVERLOAD CAPABILITY AND DIRECT FREQUENCY OUTPUT
A new torque transducer with high overload capability and direct frequency output is reported. It employs the recently developed metallic triple-beam resonators with thick-film printed lead zirconate titanate (PZT) drive and pickup elements. The new torque transducer has been tested in a torque range of up to 20 Nm, resulting in a strain level of 400 microstrain on the measurement shaft surface and giving a large frequency-change output of 800 Hz. The strain level required by the new torque transducer can be much lower (~100 microstrain) than the level (~1800 microstrain) usually required by conventional metallic resistance-strain-gauge-based torque transducers, thus increasing the transducer overload capability by a large factor. Nevertheless, under such a low strain level, the new torque transducer can still output an adequately large frequency change of 200 Hz for measurement. Having a large overload capability is very important in many torque measurement applications where rapid and large overloads can occur.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Georg Wegener, Jürgen Andrae
MEASUREMENT UNCERTAINTY OF TORQUE MEASUREMENTS WITH ROTATING TORQUE TRANSDUCERS IN POWER TEST STANDS
The objective of the presented study is to introduce a method for estimating the measurement uncertainty of torque measurements. Unlike the well-known approaches, the uncertainty shall take into account the effects acting during torque measurement in industrial applications like power test stands. These effects include the effects also known from laboratory calibration like hysteresis, linearity or interpolation deviation, repeatability, reproducibility. But special emphasis is put on an estimation of their impact under the conditions in the power test stand. Additionally, further effects are included in the consideration, like temperature effects, the influences of parasitic loads and of rotational speed. The mathematical method for an estimation of the uncertainty is presented, the input quantities are discussed and suggestions are made how the uncertainty can be reduced for given applications.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Jong-Ho Kim, Hyo-Jik Lee, Jeong-Il Lee, Yon-Kyu Park, Min-Seok Kim, Dae-Im Kang
FABRICATION OF A THREE-COMPONENT FORCE SENSOR USING MICROFABRICATION TECHNOLOGY AND ITS EVALUATION
This paper describes the development of a three-component silicon-based force sensor with a square membrane using bulk micromachining process. The designed sensor, with size of 2 mm x 2 mm, has a maximum force range of 5 N in the x, y, and z direction. Optimal locations of piezoresistors were determined by the strain distribution obtained from finite element analysis and beam theory. Finally three Wheatstone bridge circuits were arranged and verified under Fx, Fy, and Fz loading conditions. The silicon-based sensor was fabricated using bulk microfabrication technology(MEMS). The piezoresistors for measuring the change of resistance, like strain gage, were embedded in silicon wafer (Si) using ion- implantation diffusion technique. An epoxy mesa(SU-8) is built-up on top of the silicon to convert an applied force to a distributed stress. Finally, the membrane of the sensor was fabricated by using bulk- micromachining process based on the anisotropic etching of the silicon. The ability of the sensor to measure both normal and shear forces is investigated and demonstrated through experimental characterization such as normal and shear sensitivity, repeatability, hysteresis and linearity.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Thomas Fehling, Thomas Fröhlich, Detlef Heydenbluth
THE NEW SARTORIUS 1KG-PROTOTYPE BALANCE FOR HIGH PRECISION MASS DETERMINATION
The 1kg-prototype balance is a result of the technical collaboration between the Sartorius AG and the BIPM. Construction and functionality of the 8-position load alternator are based on the known BIPM FB2-technology. The 1kg-Prototype balance is constructed for highly accurate mass determination and is developed to create and maintain the national mass scale as well as the use for research and development. It permits the weighing of Pt-Ir or stainless steel masses from 100g to 1 kg as well as 1kg silicon spheres or buoyancy artifacts. The complete measurement device is installed inside an enclosed airtight aluminum chamber which can be evacuated to primary vacuum. The load alternator can be loaded comfortably through a quick load-lock device. Additional standard vacuum flanges are freely available for measuring sensors, control purposes and electronic or other connectors. The control unit running the control software allows flexible and easy programming of the required measuring sequences. Routine matter mass calibration as well as complex weighing series could be done. A detailed description of the technical and metrological parameters and possible applications are given. The function of the load alternator and the load-lock device is depicted.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Andy Robinson
THE COMMISSIONING OF THE FIRST UK NATIONAL STANDARD STATIC TORQUE CALIBRATION MACHINE
At IMEKO - XV World Congress, the design of the first UK national torque calibration machine was described. Following the construction of the machine, this paper describes its commissioning, leading to the establishment of the first UK national static torque calibration standard. The novel vertical transducer orientation is made possible through several innovative sub-assemblies. This paper evaluates the performances of these critical sub-assemblies, and compares them against design specifications.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Andy Knott
DESIGN, DEVELOPMENT, AND COMMISSIONING OF A 120 kN DEADWEIGHT FORCE STANDARD MACHINE
This paper describes the development of a 120 kN deadweight force standard machine and its commissioning in late 2003 / early 2004. The rationale for developing a machine of this capacity is given together with details of its design, focusing in particular on the scalepan and weightstack arrangements. The calibration of the masses is described and an uncertainty budget for the force generated by the machine, resulting in an expanded uncertainty of ±0,001 %, is given. Information on the construction of the machine is also given, as are details of the control system. The results of comparison tests between the machine and NPL’s other deadweight machines, carried out as part of the commissioning procedure, are described. The conclusion is made that the machine will be suitable to act as the pilot machine in a forthcoming CIPM 100 kN Key Comparison.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Y.K.Park, R.Kumme, J.T.Lee, W.Herte, H.K.Song, D.I.Kang
ESTABLISHMENT OF FORCE STANDARDS IN KOREA UP TO 2 MN BY HYDRAULIC FORCE STANDARD MACHINE
The force unit generated by the 2 MN hydraulic force standard machine in KRISS was changed to Newton from kilogram-force. This paper describes the estimation of the hydraulic force standard machine. First, the machine was compared with a 500 kN deadweight force standard machine in KRISS. The relative deviation between two force machines was less than 2 x 10^-5. In order to estimate the hydraulic force machine in the whole range, we made an intercomparison with a 2 MN deadweight force standard machine in PTB. Intercomparison test revealed that the relative deviation between the KRISS hydraulic force machine and the PTB deadweight force machine is less than 8.1 x 10^-5 in the range of 400 kN to 2000 kN.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Y.K.Park, M.S.Kim, J.H.Kim, D.I.Kang
A PROPOSAL FOR AN EVALUATION METHOD OF FORCE STANDARD MACHINES BY USING BUILD-UP SYSTEM
This paper describes a new method to evaluate a force standard machine by using a build-up system. The sum of three force signals from three force transducers in a build-up system can be used as a reference value for an intercomparison of force standard machines. At the same time, the small amount of differences between force signals from the build-up system can be used to estimate side force components of a force standard machine. This paper explains theoretical derivation and assumptions of the method. One example of using the method is included in this paper. A 500 kN deadweight force standard machine was examined by using the propose method.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

N. Khélifa, M. Lecollinet, M. Himbert
MOLAR MASS OF DRY AIR IN MASS METROLOGY
Since 1980, the different national metrology institutes use the same procedure and formula for air density determination. The formula employed assumes some hypotheses on the composition of dry air and is expressed in terms of its molar mass and the four environmental parameters: air pressure, air temperature and concentrations of carbon dioxide and water vapour. In this formula (known as CIPM-1981/91) recommended by the Comité International des Poids et Mesures, the mole fraction of argon is fixed at 9.17×10^-3. This value is now questioned and new measurements involving different techniques, are of great interest. This paper describes the experimental set-up used to evaluate the concentration of argon relative to that of nitrogen contained in air sampled from mass laboratory. The method uses a flexible capillary tube, maintained at constant temperature, for gas admission. With this system, air from different samples of atmospheric air is introduced into the vacuum chamber to be analysed. Preliminary measurements show that the value of p_Ar/ p_N2 is closer to 1.196x10^-2, given in some publications, than the value of 1.174x10^-2, used in the current method for air density determination. In the future, comparison between argon and oxygen concentration will allow a more precise measurement with regard to the existing values.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Stuart Davidson
THE USE OF X-RAY PHOTOELECTRON SPECTROSCOPY TO ESTIMATE THE STABILITY OF PRIMARY MASS STANDARDS
Because it is still defined in terms of an artefact, the limit on the accuracy with which the SI unit of mass can be realised is largely limited by the surface stability of the kilogram standard. Not only is this true on the case of the International Prototype used to define the unit but also for national standard copies and indeed for mass standards in general. This paper describes the use of x-ray photoelectron spectroscopy (XPS) to study the accretion of contamination of the surfaces of standard masses. Angle resolved X-ray photoelectron spectroscopy (AR XPS) was used to characterise the surfaces of platinum-iridium and stainless steel mass standards stored either in air or in vacuum, or which have been transferred between the two media. Various analysis methods for XPS data have been compared both in terms of providing an overlayer thickness on the mass standard and in terms of analysing the composition of this layer of contamination.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Zhu Zijian
RESEARCHES ON FUNCTION-LINK ARTIFICIAL NEURAL NETWORK BASED LOAD CELL COMPENSATION
A new approach to load cell compensation modeling based on a function link neural network is discussed in this paper. It firstly introduces the function-link neural network to compensate both linearity and temperature effect of a load cell. An example is given to illustrate the proposed method. Various of coefficients of this network is discussed including the different compensation results on three functional expansion, the relationship between initial learning step and compensation accuracy and etc. A proper network is worked out to compensate load cell up to OIML C10 degree in this paper. This neural network compensation of the above errors was achieved via micro controller. Results in this paper indicate that with above compensation the accuracy of a transducer could be improved greatly. This approach for sensor modeling is superior to the existing techniques. It has a potential future in the field of measurement.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. I. Mohamed, E. H. Hasan
THE METROLOGICAL CHARACTERISTICS OF FORCE TRANSDUCER UNDER LOADS LESS THAN 10% OF ITS CAPACITY
In many circumstances some one may be compelled to use a force transducer under loads less than 10% of its capacity. It is so important to know the metrological characteristics of the force transducers at this small range in order to be aware how much these characteristics are poor under this force range. Two different types of class 00 force transducers are used. For each type different transducer capacities are considered. The force transducers are calibrated according to ISO 376 in compression within two ranges. These ranges are 10% and 100% of the transducer capacity. The transducer linearity, repeatability, reproducibility and reversibility are compared for the two applied ranges. For the same force transducer each rang is considered as a separate force transducer, so each parameter is evaluated as a ratio from the full range capacity.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

A. M. Abdel Kareem, A. M.Fawzy, S.Khisk, A.Eltawil
Improvement of Mass Determination Using AT-1006 Comparator in NIS – Egypt
A major factor determining the uncertainty associated with the value of a standard mass at any level is the performance of the mass comparators employed at various levels in the traceability chain. Improvement in the uncertainty of mass standards is thus dependent on the research and developments of better mass comparators. The National Institute for Standard (NIS) Egypt was equipped in 1997 with Mettler AT-1006 comparator to compare masses in four positions. The comparator capacity from 50 to 1000 g is of particular interest, since this range is the range in which the comparisons against the national prototype kilogram are carried out. Controlling software has been adopted to work with the Mettler AT-1006 comparator for driving the balance to execute any comparison scheme. New climatic system for measuring the air density was established for Measuring the ambient parameters and combining them in the well-known BIPM 1990 formula enable measuring of the air density in the laboratory indirectly. The performances of the system were studied as well as an estimation of expanded standard uncertainty calculations were carried out. Improvement in the comparator performance after using the new control software has been achieved and the climatic system.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Christian Müller-Schöll, Roland Nater
A MASS COMPARISON AROUND THE WORLD
A group of nine calibration laboratories performed an intercomparison of Conventional Mass in 2004. The comparison consisted of conventional mass for four weight pieces, namely 100 g, 10 g, 100 mg and 2 mg. All participating laboratories are accredited for this measurement. However, they are distributed around the world on different continents, they are accredited under different accreditation bodies and are traceable to different national standards. This is special, as usually calibration laboratory intercomparisons are performed in one country only or among laboratories that are accredited by one accreditation body. In this intercomparison the only common point of traceability is the international kilogram prototype and the only common point of the quality assurance system of the participants it is their accreditation according to ISO 17025. The paper deals with the results of the intercomparison and hints at problems and findings that can be drawn from the evaluation of the results.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Andreas Lindau
A MAP BASED ALTERNATIVE FOR THE DETERMINATION OF THE LOCAL GRAVITY
For the determination of the local gravity high precise mobile gravimeters are in use since more than a hundred years. As a result of the basic measurement principle the determination is carried out point-by-point with the consequence that the procedure is time consuming and expensive. Thus in many countries the results of several measurement campaigns have been collected over decades. Whereas the measured values are available to the public only to some extent, the data were of- ten processed to gravity anomaly maps for the purpose of geological ground surveys. In this research two samples of gravity anomaly maps of Northern Germany and Italy are intro- duced with a detailed description of the rebuild of a gravity value from an anomaly map. For the single steps a theoretical budget of the uncertainty is given which has been verified by inde- pendent control points.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

R. Oliveira, L. Cabral, U. Kolwinski, D. Schwind
PERFORMANCE OF THE NEW PRIMARY TORQUE STANDARD MACHINE OF INMETRO, BRAZIL
A new design of primary torque standard machines (TSM) with feedback-control of the lever support was described at IMEKO – XVI World Congress in Vienna [1]. The purpose of this paper is to present the performance of a hand operated option model in the wide range from 2 N·m up to 3000 N·m. Influences of hand operation are estimated as well as ambient influences like temperature changes and air flow. A protection chamber against the ambient influences was built and the improvement is shown. The TSM has three mass stacks to cover all transducer capacities from 20 N·m up to 3000 N·m in each ten steps. The masses are calibrated within 5·10^-6 by German DKD. The lever arms were precisely adjusted and also DKD-calibrated within 5·10^-6. The adjustment procedure is described. The measurement uncertainty is calculated by the design data according GUM. In addition the best measurement capability of the TSM and the relative deviations are calculated by the results of several torque transfer standards, former calibrated at PTB. Both calculations are compared. The next steps of the upgrade concept – from a hand-operated model to a full-automated model – are illuminated regarding the requirements in Brazil.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Aimo Pusa, Michael Sachs
INFLUENCE OF COUNTER ROTATING BEARINGS IN TORQUE CALIBRATION DEVICES
This article is concerned with the use of counterrotating mechanical bearings in torque calibration sys- tems. First a short overview on some general aspects of this bearing type will be given, which includes a general description of their construction as well as of their functionality. The main section deals with experimental examinations made on the performance of counterrotating bearings. These experiments were completed mainly using the horizontally arranged MIKES-RAUTE 2 kN·m torque standard calibra- tion device. Additionally initial results gained with the new vertically arranged 20 kN·m torque reference device are included. Main points of interest were the particular elements of the uncertainty budget as stated in EA-10/14. They are opposed for counterrotating and standing bearings. Also some investiga- tions about other error influences of the bearings are presented. Overall these results show that counterro- tated bearings can provide a strong reduction of uncertainty but also need some further investigation es- pecially in vertical devices.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Timothy Changlin Wang, Qihao Yuan, Arthur Reichmuth
USING LOWER CLASS WEIGHTS TO CORRECT AND CHECK THE NONLINEARITY OF BALANCES
Any electronic balance has more or less nonlinearity. This paper presents a method to correct and check the nonlinearity by using two sets of lower class weights. Some of the key causes of the nonlinear error are described first. Common-meet parabola nonlinear pattern were studied in detail. A correcting procedure, using a set of lower class or even no class weights is then described. The correcting coefficient is given in the paper in an apparent form. Simulation and test results showed the nonlinear error reduced dramatically with the method. A check process is required before a balance goes to the market to test whether the final nonlinearity is within the tolerance. A check procedure, namely differential method, is presented. The method is accurate enough by using a second set of lower class weights. Low cost, high efficiency and good quality can be achieved in balance production by using the method presented.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. Ibrahim, G. Aggag
COMPARISON BETWEEN THE CONTINUOUS AND STEP BY STEP CALIBRATION METHODS OF FORCE TRANSDUCERS
The continuous calibration method of force transducer represents a very helpful method since the calibration can be carried out in a short time compared with the step by step method. Another advantage of the continuous calibration method is the possibility of recording the responses of the standard force transducer and the force transducer to be calibrated synchronously. This could be done using two different channels of the displaying device. The disadvantage of this method is the difficulty to define exactly constant certain loads at each loading series during the calibration. The continuous method shows better measurement uncertainty than the step by step method, where as a lot of calibration points are considered in the analysis. One important factor for the results of the continuous calibration method is the response rate. Rates less then 0.08mV/Vs showed good agreement results of the two methods.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Jin-Hun Sohn, Ji-A Suk, Chang-kyu Lee, Jin-Seop Eum, Bae-Hwan Lee, Soon-Cheoul Chung, Dae-Im Kang
BRAIN MAPPING WITH ELECTRO-TACTILE STIMULATION OF THE FINGERS: AN FMRI STUDY
The purpose of this study was to investigate differences in brain activation by electrotactile stimulation of two fingers of the right hand with different frequencies using fMRI. Non-painful electrotactile stimuli were delivered. Significant activation produced by the stimulation were found in the SI, SII, subcentral gyrus, precentral gyrus, and insula. In all participants statistically significant activation was observed in the contralateral SI area and bilateral S? areas by the stimulation on the fingers but ipsilaterally dominant. The SI area representing the second finger generally located in the more lateral and inferior side than that of the third finger across all the subjects. But no difference in brain area was found for the stimulation of the fingers by different frequencies.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Tokuji Okada, Ken-ichi Kurosaki, Karsten Berns, Ruediger Dillmann
MEASUREMENT OF RESULTANT ACCELERATION UTILIZING A WEIGHT BALL ROLLING IN A SPHERICAL SHELL
This paper describes measurement of resultant acceleration of motion and gravity in 3D space based on sensing a metallic ball position on elastic layer housed in a spherical shell. Construction of different types of silicon rubber is introduced and their displacements against pressure are calculated by using the Hertz' law. Since the resultant acceleration makes the ball roll toward the direction to find a balanced position in the shell, the center position of the metallic ball is measured. The rubber layer is concentric to the shell and liable to distort so that three proximity sensors of high-frequency oscillation type can detect characteristics of sink versus pressure. We show measurement principle of extracting the acceleration by using the characteristics. Experimental results are shown and compared among various rubbers to have the most appropriate design of the sensor. We got practical data such that angular error less than ±7.4 deg; amount error less than 2.86 x 10^-2 m/s²; force sensitivity 4.9x 10^-2 N; insensible range less than ±3.8 deg; periodic time 95 ms.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Yoshikazu Watabe
JCSS (JAPAN CALIBRATION SERVIVCE SYSTEM)
JCSS is an accreditation system operated by IAJapan (International Accreditation Japan) in line with ISO/IEC 17025 as accreditation criteria. This paper introduces our latest investigation of JCSS, MRA (Mutual Recognition Arrangement) for Laboratory Accreditation, Tendency of its activities and Requirements of its users.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Jorge C. Torres-Guzmán, Diedert Peschel, Daniel A. Ramírez-Ahedo
THE TORQUE NATIONAL STANDARD FOR 20 kN·m in MEXICO
This paper presents the needs in Mexico for larger ranges in torque calibration. The design of a torque standard to meet, and surpass, those needs are here included. The general design considerations, the layout of the system and the subsystems designed for the torque national standard for 20 k·Nm in Mexico are discussed and included in this paper.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Jorge C. Torres-Guzmán, Daniel A. Ramírez-Ahedo
SIM FORCE STANDARDS COMPARISON UP TO 10 kN
A comparison in the quantity of force was carried out among the SIM national laboratories in order to estimate the level of agreement for the realization of the quantity and the uncertainty associated to its measurement. This comparison was carried out up to 10 kN. The equipment used consisted on two force transducers (load cells); both with the same measuring range (10 kN). With the purpose of obtaining maximum accuracy on the transducers, the comparison range was selected from 4 kN up to 10 kN. This comparison provides a link to CIPM Key Comparisons. The results obtained, as well as the reference values selected for the comparison are included in this document. Two different methods were used to analyze the level of agreement and to state the conformity declaration.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Boris Katz, Liron Anavy, Itamar Nehary
The calibration system of force measurement devices - conceptions and principles
Developed, put into practice and used the universal automatic system MABA-2000 for calibration of force measurement devices in accordance to ISO 376-1999, ISO 7500-1999 and manufacturer requirements. The system includes a set of load cells from 1 kN to 5 MN, amplifier DMP-40 (HBM), computer and accessories. Mathematically proved the possibility of calibration in points, which vary from series to series, proved, and confirmed the application of calculation of formulas accuracy deviation and repeatability in accordance to ISO 7500-1999. This approach increases the productivity and simplifies the calibration process. Software MABA-2000 permits to communicate the measurement line “load cell-amplifier-computer” and to perform calibration process on mode ON-LINE: input of the measurement data, indications of the deviations in real time, calculations of the uncertainties, calculations of the calibration results and output of certificate. For calibration by method of Dead Weight a computer automatically selects a set of standard weights as a function of the True Force and value of gravity acceleration. The strict and precise method of the measurement results’ rounding optimizes the value of uncertainty. Calculation of interpolation polynoms of 1st, 2nd, 3rd degree is done automatically too, and does not require additional resources or time. The software MABA-2000 includes also the subroutine for the measurement load rate and calculates uncertainty in accordance to customer requirements.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Liron Anavy, Boris Katz
UNCERTAINTY AND INTERPOLATION
This article deals with interpolation methods, ways to determine which method is required and ways to check the results’ fitness.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

M. Peters, D. Peschel, R. Kumme, D. Mauersberger
PTB's 'new' 2 MN Deadweight Force Standard Machine
In this contribution, the new 2 MN deadweight force standard machine of PTB, which was moved from Berlin to Braunschweig and has been completely modernised, is presented. The determination of the mass of the deadweights with a special mass comparator is described. The uncertainty of the machine is theoretically analysed and experimentally verified by force measurement procedures.
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

Shang Wei Lu, Li Tao, Cheng Yong Pei, Wang Yan, Qian Zhao Jun
50 kNm TORQUE STANDARD MACHINE
The paper introduces the working principle of dead-weight balance type 50kNm torque standard machine , which was developed recently. The paper describes in detail the key technique , etc. such as the knife edge supporting technique with high load , the force magnifing technique , the alignment technique and the computer control automatic loading technique , etc. The paper analyses the uncertainty of the machine and the compared and verifyed data with LNE . The uncertainty of the 50kNm torque standard machine arrives at 0.023%(tp=3.1).
19th Conference on Force, Mass and Torque Measurement, Cairo, Egypt, 2005

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