9762 papers found
This document describes the new construction of Plantograf V12. In this report, the design of electrodes and using pressure distribution measurements between the tire and road contact surface are discussed. The resulting measurements will be applied when designing new road and agricultural vehicle tires.
In this paper, efforts have been made to develop a Wireless Sensor Network based system to monitor physical parameters of a moving object or geographically distributed sensor array. Using this system one can monitor the parameters of the moving object to ensure its optimal movement. Such objects include automobiles, aircraft etc, while the parameters may be acceleration, rate of change of g (acceleration due to gravity), or inclination. Whenever any of these parameters crosses the set limits, the system will give suitable indications. The sensors to monitor these parameters would be part of...
KTL has forced piston gauge which generate very low pressure (1 Pa ~ 1400 Pa) stable. Prior to forced piston gauge, we calibrate with digital manometer or capacitance diaphragm gauge below 1400 Pa (uncertainty: 0.011 %). This paper will introduce uncertainty evaluation of new standard by means of cross-float.
The development of a system for determining step response of total vacuum gauges is described as well as results for some typical vacuum gauges. The system is mainly suitable for steps from atmospheric pressure down to around 50 Pa. Step response times reached with the system are (with reasonable sizes of DUT internal volumes) about 20 ms.
This paper describes internal method for determination of pressure balance piston fall rate using simple camera-based optical system with laboratory developed software. Measurements were carried out on three standard piston/cylinder units in Croatian National Pressure Laboratory (LPM) using gas and oil as transmitting medium. Measurement equipment, procedure and fall rate results for three set of measurements are given as well as evaluation of measurement uncertainty. Results were compared with other relevant measurements.
Metrological characteristics of 1 GPa controlled clearance piston gauge (CCPG) were investigated using a finite element method (FEM). These are a piston/cylinder distortion coefficient in free deformation mode, distortion coefficient of jacket pressure and stall pressure in controlled clearance mode. The effective area of CCPG was constant according to different applied pressure when relative jacket pressure of 17.3 % was applied. Comparison experiments with KRISS 500 MPa standards were carried out to verify the FEM results.
New pressure measurement technique using acoustic impedance ultrasonic transducers was studied. Aircoupled ultrasonic transducers of 500 kHz frequency were used in the pressure range 1.33 × 10 3 Pa – 2.03 × 10 5 Pa. In the pressure range almost linearly proportional results were obtained for all five He, N 2 , Dry air, Ar, and Kr gases. It is suggested that the ultrasonic transducers can be successfully used for pressure measurements as it has many advantages against other measurement methods.
This paper describes how to implement a high dynamic pressure instrument using a step pressure generator and standardization based on a medium density equation. The step dynamic pressure without any big vibration due to an impulse caused by a trigger mechanism is generated upto 800 MPa. A basic design concept to eliminate the unnecessary vibration is proposed. In addition, density equations according to pressure are used to establish the high dynamic pressure standard. On the other hand, the effectiveness of conventional sebacate(di-2-ethylhexyl sebacate) oil density equations could be...
A primary vacuum standard for UHV pressure range is under development in Czech Metrology Institute (CMI). In order to cover the UHV range down to the limit 1 × 10 -10 Pa a method of calibration in non-equilibrium gas (so called dynamic extension method) was employed. The apparatus is divided into three parts: the dynamic extension stage, the orifice flow standard and the flowmeter. The dynamic extension stage is designed as an XHV apparatus manufactured from a low outgassing rate material – beryllium copper alloy. A special 4 K bakeable refrigerator cryopump is used as the main pump.
Pressure gauges including strain-gauge transducers and Manganin gauges are calibrated and characterized in the pressure range up to 1 GPa. For the calibration and characterization, the pressure generating system using a pressure balance and a precise pressure multiplier has been developed as a pressure standard. In this paper, the pressure generating system, the method for calibrating the pressure gauges by using the system and the results obtained are presented. The temperature coefficients of Manganin gauges are also evaluated in the pressure range.