9762 papers found
The ways of modeling of supervisor’s action measurements in control of multi-agents mobile robotic subsystem using cognitive idea are discussed. The architecture of a transport subsystem, which can work efficiently both in the newest and existing manufacturing systems as well as rules for co-operation and coordination of vehicles have been presented. Computer simulation results are given.
For any measurement to be meaningful, the result of the measurement must be accompanied with a statement of its uncertainty. The evaluation of uncertainties associated with pressure measurement is sometimes complex but an important task. This paper presents a systematic approach for estimating measurement uncertainty by providing a worked example for the case of pressure measurement by a pneumatic dead-weight tester.
This paper describes the way by which the National Pressure Laboratory in Brazil has been calculating its calibration measurement capabilities (CMC) using the uncertainty estimations contained in the ISO GUM 95 and declared in the appendix C of the BIPM, and verifying if there is any convergence and consistency between the measurements results calculate with both methods.
Numerical calculations of heat flux in the Pirani sens were carried out for a wide range of the gas rarefaction based on the kinetic Boltzmann equation. To take into account a non-diffuse gas-surface interaction the Cercignani-Lampis scattering kernel was used in the boundary condition. Such a kernel allowed us to study the influence of the momentum and energy accommodation coefficients on the heat transfer from the sensor wire into surrounding gas. The present results can be applied to improve the precision of pressure measurements by Pirani sensor.
This comparison constitutes the first vacuum comparison among National Metrology Institutes (NMI) within the Interamerican Metrology System (SIM). Each laboratory used its national standards. The Centro Nacional de Metrología (CENAM, Mexico) used a primary standard (static expansion system type) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO, Brazil) used a secondary standard (comparison system type). CENAM had the role of coordinator and pilot laboratory. The comparison started in December 2004 and finished in March 2005. The objective of the...
The purpose of this paper is to investigate the characteristics of precise low-pressure gauges such as Capacitance Diaphragm Gauge (CDG) devices in the range 133 Pa using a commercial gas-operated pressure balance. Generally the pressure balance is not adequate to calibrate such low pressure gauges as the minimum pressure to balance the tare weight corresponds to a pressure of several kilopascals. However using a variable bell-jar pressure method can overcome this difficulty. To realize this method effectively, we developed a new weight-handling device that makes it possible to add or remove...
This paper presents state-of-the-art research being carried out in Brazil for the development of methods and devices used in the dynamic calibration of pressure sensors. The work is part of an effort set forth to set up a national reference laboratory. The devices developed and their metrological characteristics are presented.
This paper describes steps involved in a new type of pressure sensing. Significance of this approach and propose approaches for improving sensitivity, resistance to electromagnetic interference, dimensions and accuracy. The goal of the project is the research of complex smart pressure sensor based on the new sensing system with galvanic fiber optic isolation including research and experimental validation of this new pressure sensing principle. The objectives of the project of applied research are in new methods and technology of pressure sensors with galvanic isolation and function specimen...
One of the methods for input signal restoration during dynamic pressure measurement in real time and its relevant piezoresistive sensor are proposed.
This paper presents the comparison between the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO, Brazil) and the Centro Nacional de Metrología (CENAM, Mexico) on barometric pressure in the range from 80 kPa up to 115 kPa. This comparison was carried out at the end of 2004 and has been entered within the data base of the Sistema Interamericano de Metrología (Interamerican Metrology System, SIM) as comparison SIM.7.25 P. The pilot laboratory was CENAM. The standards used by the national laboratories were pressure balances, operated in free deformation. The...