9762 papers found
Flow speed and frequency dependencies of vibration transfer by flowing air between tubes in a row are presented. The transfer is increasing linearly with dynamic pressure, but with frequency dependence it is a bit more complicated. Also time histories and frequency spectra of the tube vibration are caught and commented.
For research of aeroelastic behaviour of bodies at non-linear aerodynamic interaction it is necessary to measure not only the first, but also high harmonics of aerodynamic loading on vibrating bodies. In the presented work, various ways of the non-stationary aerodynamic forces determination are analysed. Substantiation of the mentioned forces measurement through a electrical current in the vibrator mobile coil is handed. That is valid under condition of the proportional - differential feedback utilising in the oscillation control system of the tested bodies.
Mathematical modelling is a key enabling tool in the analysis and design of measurement systems and measuring instrumentation. This paper highlights the importance and the use of advanced mathematical modelling techniques for design, analysis and performance evaluation of sensors and actuators in measurement and instrumentation systems. After a brief introduction, it illustrates the use of numerical finite element (FE) modelling technique for analysis and design of sensors and actuators. This is based on two case studies in which FE modelling methodologies have been used for the analysis and...
In this paper, the model of fiber optic temperature sensor is described. The sensor uses pulse coding of optical information signal, so that uncertainties caused by changes of optical signal power are excluded.
Telemetry system is the wireless measuring system constructed with sensing node(s), Host system and communication device(s). The telemetry system becomes the base technology to construct the distributed measurement system to measure in geometrical wide range. Then, it is necessary to keep load balance in the local area sensing network system. In the telemetry system, autonomous operation of the sensing node enhances the effectiveness of telemetry system totally. This paper describes the investigation of operation mode and automatic sampling control in sensing node of telemetry system.
In this paper a newly developed tack-meter is introduced. One of the major features of this tack-meter is pushing the probe wrapped in a PET film against a sample, and during pulling apart the film from the sample tack of a material is measured. And each material’s tack is compared by the adhesion to a PET film. The quality of a PET film is stable as a comparison contrast material. Another feature of the tack-meter is that it is operated full automatic and it can measure continuously at high speed. Also the tack-meter is improved in subjects of various existing tack measuring methods. They...
Non-destructive testing techniques are generally used for the evaluation of material properties and the detection of defects in pipelines. Especially, the measurement of magnetic flux leakage (MFL) is one of the most used methods for in-service monitoring of corrosion in buried oil and gas pipelines. However, for the geometrical reconstruction of defects in a pipeline from measured signals (the inverse problem), the magnetic properties of the material need to be known accurately. Due to the pipe geometry and wall thickness measurement of the bulk properties is complicated. In particular, the...
The measurement problem of super weak noise signals intensity in super-broad frequency band, which level is much lower than power of the inherent noises of measuring equipment and the external noises is urgent in many fields. The problem of this kind arises in radio astronomy, in radio thermal and plasma radiation measurements. Over last few years the electromagnetic radiation of biological objects, include humans, have been actively studied. Diagnostics of the human body is carried out from the values of radiation parameter proceeding [1]. The paper is devoted to the further development of...
Methods for the design of radiofrequency single probe-based devices for highly accurate disturbances-independent level/interface position measurements are proposed. These methods are based on the application of several (two or more) measuring channels realized with the use of a single radiofrequency probe that is the section of a TEM transmission line. In particular, realizations of radiofrequency single probe-based devices for the measurement of level, interface positions of substances in tanks, of physical properties of these substances are considered.