A new European gravity zone concept has been developed by WELMEC, the European Cooperation in Legal Metrology. This concept is independent of political or administrative borders and is accepted by all WELMEC member states regardless of existing national regulations concerning gravity zones. The new concept is based on gravity zones defined in terms of the geographical latitude φ and the height above sea level h, on a standardised gravity formula used for the adjustment of a weighing instrument to a reference gravity value, and on a uniform criterion for calculating the maximum permissible variation Δg/g within an individual gravity zone. The concept is of advantage especially for weighing instruments of class III. It offers an option that can, but must not be chosen by a manufacturer.

The results of the calibration of load cells (force transducers) according to ISO 376-1999 are described in table of values where force F (kN) is a function of electric signal R (mV/V) and by analytical approximation of the calibration curve. The analytical approximation is usually expressed by polynom of 2nd or 3rd degree. The measurement of force in the calibration of testing machines by means of digital unit device DMP-40 (HBM) suppose application of linear interpolation between two adjacent values of signal R. By means of mathematical calculations it is theoretically proven in which cases the linear interpolation is undesirable and leads to additional interpolation error, and increasing of the value of uncertainty measurement in accordance. A few studies and experiments of the issue confirm the theoretical conclusions: in some cases minimizing interpolation error and uncertainty measurement in measuring force F as a function of reading the signal R, can be achieved by approximation polynom instead of linear interpolation between two adjacent values. For this purpose QCC Hazorea has developed program called “MABA-2000,” which can solve this problem.

In the paper the structure and the operating principle of impulsive force and pressure sensors applied in tasks of reconstruction is presented, which feature one point and two point measurement of the strain inside a Hopkinson bar type mechanical transducer. A comparison between the two versions of the sensor was carried out, taking into consideration the processing accuracy, the complexity of the conditioning circuit and the input signal processing circuit. The preferred application range is given for each version of the sensor.

A new dead weight force standard machine covering the range from 5 kN to 500 kN direct weights has been designed and constructed at the National Institute for Standards (NIS)- Egypt, by Gassmann Theiss Messtechnik GmbH (GTM). The machine capacity can be duplicated to 1000 kN by means of a substitute force generator. The machine has been verified through a comprehensive Inter-laboratory Comparison Programme run over a period of two years at the Physikalisch-Technische Bundesanstalt (PTB) of Germany and NIS of Egypt. A well-selected set of high precision force transfer standards was used in the comparison calibration protocol. Rounds of measurements were carried out on deadweight machines at both the PTB and NIS. This paper presents the protocol followed to evaluate the metrological characteristics of the new machine as well as the Inter-laboratory Comparison scheme used in the verification process. The results prove that the machine achieve an uncertainty better than 2·10^-5 for calibration of force transducer by pure deadweights. Using the substitute force generator mechanism to double the machine capacity resulted in an uncertainty figure better than 1·10^-4.

An important element in the supervision of buildings is the necessary precise and continuous measurement of stress conditions. For this purpose, an encapsulated measuring sensor as developed which protects the sensitive strain-gauge technology within it and which can be easily inserted into measurement boreholes. The mechanical adaptation is effected by optimising a process of deformation of two conical bodies such that the envisaged measuring range covers the range of elastic deformation of construction steels. Suitable calibration procedures as well as measurement methods for the early detection of structural damage in buildings were developed for this adaptation model. A strain-gauge layout was devised for the sensor that is adapted to the specific local conditions, and the strain gauge is protected by a plastic seal. In order to be able to assess the lifetime of the sealing materials, which in part were being employed for the first time, the chemical/climatic building environment was simulated under forced conditions in the laboratory.