Waves In Piezoelectric Crystals Research Articles

Excitation and detection of surface elastic waves in piezoelectric crystals: Joshi, S.G., White, R.M., JASA, vol 46, no 1, part 1 (July 1969) pp 17–27

Previous research has shown that the performance of a single piezoelectric (PZT) fan cooling system that is strongly affected by the operating frequency, fan amplitude, fan arrangement, and power consumption. Moreover, new dimensionless numbers, including Mp and Ri, have been defined to analyze the performance of the cooling system. In this study, an innovative multiple vibrating-fan cooling system has been developed by using PZT force and magnetic force. In this design, a PZT plate can be used to actuate five vibrating fans simultaneously. The performance of the system is demonstrated by the total amplitude of the system. The total amplitude of the single PZT fan system was 8 mm while the total amplitude of the multiple vibrating-fan system was 31 mm under the same power consumption. Furthermore, the multiple vibrating-fan system can be embedded into a heat sink directly. The temperature of the heat sink dropped from 67 °C to 50 °C when the system was operated under the condition of 36.4 Hz, 50 V, and λ = 2 mm. The result shows that the temperature drop reaches 17 °C under a power consumption of 0.03 W.

Excitation and Detection of Surface Elastic Waves in Piezoelectric Crystals

The amplitude of the surface elastic wave produced by the application of an alternating voltage to an interdigital arrangement of electrodes on the surface of a piezoelectric medium is determined. The electric field produced by the surface electrodes is calculated subject to the assumption that the piezoelectric coupling of the material can be neglected. This electric field acts as the forcing term for the inhomogeneous elastic equation, which is then solved to obtain the amplitude of the surface wave generated by the transducer. A reciprocal relationship between the excitation and detection problems is used to obtain the power extracted from the surface wave by an interdigital arrangement of surface electrodes. Measurements made on single crystals of quartz and cadmium sulfide are found to be in good agreement with theoretical predictions. The maximum value of the product (efficiency×fractional bandwidth) for a surface-wave transducer is calculated. For an interdigital surface-wave transducer on the basal plane of CdS, the maximum value of this product is found to be 7.8×10−2. It is shown that one can connect linear pairs of surface electrodes in an appropriate binary code so as to obtain high efficiency and large bandwidth transducers.

Transformation of electromagnetic and ultrasonic waves in piezoelectric crystals: Ganapol 'Skil, E.M. Soviet Physics-Solid State, Vol 10, No 4 (october 1968) pp 777–784 (Translated from Fizika Tverdogo Tela Vol 10, No 4 (April 1968) pp 982–992)

Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process.