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Dielectric Properties
Published in Daniel D. Pollock, PHYSICAL PROPERTIES of MATERIALS for ENGINEERS 2ND EDITION, 2020
Piezoelectric materials can act as transducers because a mechanical strain induces an electric field and, conversely, an electric field induces a mechanical strain, or a dimensional change. Several mechanical modes of vibration may occur naturally in peizoelectric crystals because s and d vary with the crystalline direction. The geometry of the structure cell, the elastic constants, the dimensions of the crystal, and the orientation of the crystal with respect to an applied field will determine the frequencies of vibration. The application of an alternating field across a piezoelectric crystal will cause it to oscillate. The maximum amplitude of vibration is obtained when the alternating field is at the resonant frequency of a given crystal. This is determined by the factors noted previously, especially s and d, which are anisotropic.
Electronic materials for transducers: sensors and actuators
Published in David Jiles, Introduction to the Electronic Properties of Materials, 2017
A transducer is any device that converts one form of input energy into a different form of output energy. In other words it is an energy-conversion device. A common example is a device which converts mechanical energy into electrical energy, such as a piezoelectric transducer. In fact, the original use of the term transducer was specifically for a device which sensed mechanical input energy and converted it into electrical output energy. However, the term is now used to include any device which converts one form of energy to another. The efficiency of a transducer is a useful parameter which measures the ratio of output energy to input energy. Examples of transducers are loudspeakers, ultrasonic vibration generators, thermocouples, microphones and various forms of magnetometer.
Measurement Technology
Published in Stephen Horan, Introduction to PCM Telemetering Systems, 2017
A transducer has two possible realizations: a measuring transducer and an actuator. A measuring transducer is a “device, used in measurement, that provides an output quantity having a specified relation to the input quantity” [VIM12]. An actuator works in the reverse direction in that it takes an input signal generated in the payload and produces an output that works on the environment. The measuring transducers create the telemetry data and the actuators respond to the telecommand data. Figure 2.4 illustrates the relationship between transducers, sensors, actuators, and the operator. The sensor supplies information about the environment to the user. The actuator changes something in the environment at the operator’s direction. The hybrid allows both actions in one device.
Numerical simulation of planing motion and hydrodynamic performance of a seaplane in calm water and waves
Published in Engineering Applications of Computational Fluid Mechanics, 2023
Zhijie Song, Rui Deng, Tiecheng Wu, Xupeng Duan, Hang Ren
We used %MAC to calculate the weight and balance with respect to the aircraft datum and The Mean Aerodynamic Chord (MAC) is 26% in this paper. As shown in Figure 2, the seaplane model components mainly include the fuselage, wings, flaps, elevator and some parts. The parameters of seaplane model are listed in Table 2. To monitor the motion and suction of the seaplane, we have selected three representative measurement points. The transducers records the pressure, speed, acceleration, and other response information of the seaplane. These points are located at the fore, near the centre of gravity, and the aft of the seaplane. Transducers were installed at these measurement points to collect data, which was then utilized for experimental analysis and subsequent numerical comparisons. The horizontal distances from the transducers to the frontmost point of the seaplane model are 555, 1610 and 2930 mm respectively. The PCB acceleration transducers used in this experiment have a measuring range of 2 g, with an accuracy of 5%. The displacement transducer has a measuring range of 1 m, with an accuracy of 1%. The angle transducer has a measuring range of , with an accuracy of . The force transducer has a measuring range of 40 kg, with an accuracy of 0.01 kg.
Properties and numerical simulation for self-weight consolidation of the dredged material
Published in European Journal of Environmental and Civil Engineering, 2020
Liang Wang, Jinshan Sun, Minsheng Zhang, Lijing Yang, Lei Li, Jinhui Yan
The pore water pressure measurement apparatus is shown in Figure 2, which is similar to the ‘overpressure mode’ measurement method (Alexis, Lebras, & Thomas, 2004). The pore water pressure ports are screwed into the column wall at intervals of approximately 2.5 cm from 0 to 12.5 cm near the base and approximately 5.0 cm further up the column. The ports connect through cigarette filters to a tube leading to a pressure measuring unit that contains a single pressure transducer. The measuring range and accuracy of the transducer is 0~35 kPa and ±0.05% full scale, respectively. The transducer is connected via the pressure measuring unit and tap to each of the different ports and to a calibration column with a variable head for calibration before pore water pressure readings are taken. Before pore water pressure readings of the settling column are taken, a calibration of the transducer is carried out using the calibration column in different elevations. This procedure eliminates earlier problems with transducer signal drift. Pore pressures are derived from transducer voltage signals. Transducer from pressure measuring unit is connected to a central voltage-regulated power/switching box. Signals from transducer are directed to an AD converter and convert to pressures above hydrostatic using calibration equations. Data are combined and stored with port elevation and elapsed time. The accuracy of the readings is ±1 mm water head or 10 Pa, based on measurements made under hydrostatic and uniform slurry conditions. The taps and ports are carefully fixed and sealed by an adhesive and have been leakless during the whole study.
Review on Liquid-level Measurement and Level Transmitter Using Conventional and Optical Techniques
Published in IETE Technical Review, 2019
Yadvendra Singh, Sanjeev Kumar Raghuwanshi, Soubir Kumar
The sensors are designed using various techniques and different properties of liquids are utilized in the designing process. Different sensors use different sensing principles. Various sensing principles for transducer include resistive, capacitive, inductive, optical and ultrasonic techniques. An extensive review of such different techniques has been done in this paper, including proposed and simulated methods. Section 2 covers the different sensor designs while Section 3 covers transmitting technologies followed by conclusion in Section 4.