9762 papers found
Reciprocal gravitational attraction among the masses of deadweight machines could be significant in certain conditions. A simulation with finite elements method was applied on two different types of deadweight machines: INRIM force standard machines Amsler 100 kN and Galdabini 1 MN. Results are reported in comparison with the simplified method that considers the masses concentrated on theirs barycentres.
Power distribution lines are a major source of interference in ECG recordings obtained with surface electrodes. Displacement currents coupled to electrodes, their leads and directly into the body, and stray capacitance in power supply transformers, result into differential-mode, common-mode and isolation-mode interference. Shielding electrode leads reduces displacement currents coupled to them. Amplifiers with high common-mode and isolation-mode rejection ratio reduce common-mode and isolation-mode interference, but interference coupled in differential mode cannot be reduced by shielding...
The design and development of a series of pressure balances, operating in liquid media up to 120 MPa, have been started during a recent collaboration between the Italian company SCANDURA & FEM and the I.N.Ri.M. (Italian National Research Institute of Metrology) in Italy. The details of the project design for these pressure balances are here presented. Two different pressure balance’s lines have been develop: one, the RedLine, only mechanical, the other one, the BlueLine, with an on board electronic compensation system. The main chosen strategy has been decided in such a way to produce a...
The use of high-tech plastics in the field of mechanical engineering is increasing dramatically. The time-dependent change of strain ε ( t ) during constant load (viscoelasticity, creeping) is a fundamental property of plastics and exact knowledge of these properties is required for the design of plastic parts. A novel high-resolution materials testing device is presented in this paper. It offers reaction-free interferometric measurement of the viscoelastic behaviour of plastics at a constant bending load. The resolution of the deflection is 1 nm. Therefore, unlike the three point bending...
A dynamic measurement can be defined as a measurement where the physical quantity being measured varies with time and where this variation may have a significant effect on the measurement result and the associated uncertainty. New dynamic measurement challenges are arising in a number of metrology areas that have traditionally required only steady state or static characterisation of sensor performance. These challenges may require development of new measurement and calibration methods, as well as new methods for correcting sensor outputs and for the evaluation of uncertainties. This paper...
The positional deviation (difference between the actual and target position) belongs to the important criteria that describe the performance of numerically controlled axes. The procedure for determination of such deviation is described in the international standard ISO 230- 2:1997. This standard provides calculation of the positional deviation only in several discrete (measuring) points. Moreover it does not consider effects of the measuring instrument on the obtained results. The new methodology is adopted and it is enables estimation of the positional deviation in any point of the axis...
This paper deals with a measurement of wind gusts, data processing and its role in modern meteorology and connected branches. It describes some measuring devices and methods how the data are processed. It shows how to create probability map of wind gusts and graphical results.
We present results of experiments for characterising complex (i.e., multiple-scattering and time-varying) environments for propagation of microwaves. Parameters of the distortion of the received signals are analyzed using statistical and stochastic methods.
The paper notes the publication of the new edition of the International Vocabulary of Metrology as a significant step in Measurement Science. It argues that vocabularies must evolve with technical progress and with changes in society and economy. It proposes an agenda of future development of concepts and vocabulary in measurement and instrumentation. The main drivers of advance are seen to be the widening and diversification of the applications of measurement and the convergence of measurement and instrumentation and other aspects of information technology. The paper outlines some aspects...
The paper presents the proposal of a new mathematical tool for LabVIEW environment – the Large Number Library. After the short introduction describing the security issue in the Distributed Measurement-Control Systems (DMCS), the most popular asymmetric encryption algorithms (public-key encryption algorithms) are described in order to demonstrate the need for developing such a library. The LN library was implemented in two variants: the native LabVIEW code (G language) and using external software modules (DLLs). The algorithms implemented in both alternatives have been developed basing on the...