Quartz Transducer Research Articles

Composite torsional quartz transducer for shear ultrasonic measurements of aqueous liquids

A composite torsional quartz transducer has been developed for the shear ultrasonic measurements of aqueous solutions in the frequency range from 10 to 100 kHz. In order to prevent the electric interaction and low contact angle between the transducer and water, a torsional quartz crystal transducer is attached to a fused quartz rod whose surface is partly gilded by evaporation. The accuracy of +/-60 dyn/cm2 for the rigidity and +/-0.03 cP for the viscosity is attained by use of this transducer.

Thermodynamic quantities for liquid carbon tetrachloride 1. Sound velocities between 265 and 435 K and up to 62 MPa

Ultrasonic velocities (at 2 MHz) have been measured for liquid carbon tetrachloride at temperatures between 265 and 435 K and for pressures from the co-existence region up to 62 MPa. A polynomial is given for the whole range as a function of temperature and pressure, and a second along the co-existence line as function of temperature only. The mean deviation of the both polynomial fits is below ±0.60 m s −1. The experimental method used was a pulse-echo technique with a single quartz transducer.

Thermodynamic quantities for liquid benzene 1. Sound velocities between 283 and 463 K and up to 62 MPa

Ultrasonic Velocities (at 2 MHz) have been measured for liquid benzene at temperatures between 283 and 463 K and for pressures from the coexistence region up to 62 MPa. A polynomial is given for the whole range as a function of temperature and pressure, as well as for the co-existence region as a function of temperature only. The standard deviation of the polynomial fit is ±0.50 m s −1. The experimental method used was a pulse-echo-technique with a single quartz transducer. A description of the mechanical set up of the autoclave is given.

Extension of measurement times of quartz transducers by the use of a fused-quartz housing

A technique for extending measurement times of quartz transducers in planar impact experiments is described. This technique is based on embedding the gauge in a large housing made of materials whose acoustic properties are the same as those of the gauge. Lateral and free surfaces are thus removed from the gauge to the housing, and an extension of measurement times by a factor of 8 or more can be achieved.

The elastic constants of extruded polypropylene and polyethylene terephthalate

The authors have made ultrasonic measurements at 10 MHz and between 190 and 270K on extruded samples of polypropylene and polyethylene terephthalate which have a wide range of crystallinity (0-0.6) and extrusion ratio (1-10) by the use of quartz transducers directly bonded on to sample discs cut parallel, normal and at 45 degrees to the extrusion direction and have thus obtained all five elastic moduli. The results for polypropylene are considered in both the aggregate and the Takayanagi (1966) models. The aggregate model reproduces the development of mechanical anisotropy fairly well. The increase in the ultrasonic Young's modulus along the extrusion direction is much less than that previously observed in low-frequency-modulus data. The Takayanagi model shows that the stiffening effect of intercrystalline bridges is much less important for the ultrasonic moduli than for the room-temperature static moduli because of the much higher amorphous modulus for the glassy state.

Simultaneous measurement of sound velocity and sound attenuation in liquids by a correlation method

The correlation between the input and output signals of an ultrasonic ransmitter–receiver system with two quartz transducers was used for the simultaneous measurement of sound speed and sound absorption in liquids. With a correlator built from a semiconductor heterodyne detector (active mixer) followed by a low-pass filter, the space-dependent cross-correlation function of the signals, which depicts the sound field in the liquid, was recorded on a x-t recorder by continuous variation of the transmitter–receiver distance. First tests with the apparatus yielded a reproducibility of the sound velocity of ±0.1%, that of the sound attenuation was within ±3%.

Amplitude Distribution of Ultrasound in Al Rod Generated by Direct Electromagnetic Method

Amplitude distributions of ultrasonic waves (longitudinal, 10 MHz) generated electromagnetically at a surface of an aluminum rod are investigated for some arrangements of a several turned rectangular coil which is placed close to the surface and can be moved parallel to it. A quartz transducer (X-cut, 10 MHz) attached to the opposite surface of the rod is used as a receiver, and close agreement is obtained between the observed and calculated distributions of the detected voltage. Also it is pointed out that the phases of waves generated by such a method are generally not uniform over the cross section of the rod, but in case the coil plane is placed parallel to the surface of the rod, the phases of waves become rather uniform, if a half the area of that surface with the thickness of half a wavelength is cut off.

Investigation of ultrasonic cavitation in liquid helium in the Megahertz frequency range

Considerable evidence, both theoretical and experimental, indicates that the lowest-energy state of an excess electron in liquid helium consists of the electron bound in a helium-free spherical cavity of about 1.7 nm radius. This state has become known as the electron-bubble. Investigators have suggested that these electron-bubbles may serve as nuclei for ultrasonic cavitation. To examine this possibility, acoustic spectra in liquid helium were studied using quartz transducers whose resonant frequencies were in the low megahertz range. These spectra were measured as a function of displacement amplitude both above and below the lambda point. In addition, these spectra were obtained in the presence and absence of a source of electron-bubbles. Results will be compared with similar studies at lower frequencies and the role of the electron-bubble as a nucleus for cavitation will be discussed. [This work was supported in part by the Air Force Office of Scientific Research.]

Measurements of the acoustic shear impedance of superfluid3He

Measurements of the complex acoustic shear impedance of3He-B at 19 bar and 36 and 60 MHz, and of3He-A at 23 bar and 12, 36, and 60 MHz, have been made by observing the time constant and the frequency shift of the decay of a transiently excited AC-cut quartz transducer.

Observation of Transverse Zero Sound in NormalHe3

The direct transmission of transverse zero sound between two $\mathrm{AC}$-cut quartz transducers is observed in the vicinity of 3 mK; at higher temperatures the transition to classical viscous shear-wave behavior is observed through the effect on the damping of a single transducer.

Investigations of attenuation and internal friction of rocks by ultrasonics

Investigations at the frequency of 10 MHz were made to study the attenuation and internal friction in limestone and taconite. An Ultrasonic Attenuation Comparator Model-9000 (Matec Inc.) with a ‘plug-in’ and X-cut quartz transducers was used for the tests. The velocity and attenuation measurements on the two rock types have not indicated any general and definite pattern. In limestone, the attenuation coefficient is practically constant in all three measured directions, whereas it varies with direction in taconite. The coefficient of viscosity can be calculated using ultrasonic measurements. The viscosity varies in different directions of limestone but such directional variations are small in taconite. The values of coefficient of viscosity obtained are lower in comparison to those determined by resonance method.

High Q ultrasonic liquid resonators with concave transducers

Experience with cylindrical ultrasonic liquid resonators (volume 2–20 ml) in the 0.1–4 MHz range employing concave quartz transducers is reported. The static overpressure applied on the liquid cavity, which causes concave bending of the quartz, improves the Q factors of the liquid resonator (for a water-filled 15 ml cavity, up to Q∼1.1×105 near 0.4 MHz and for a 2 ml cavity up to Q∼3.4×104 near 1.8 MHz and also reduces absorption effects from gas inclusions. For illustration absorption measurements on aqueous 0.1 M MgSO4 are shown. Some analogies to characteristic properties of dielectric and optical resonators are drawn.

Measurement of elastic modulus c 11 in terbium with cds transducers

CdS transducers are found to have a strong adhesion to a well cleaned rare earth metal surface. They allow ultrasonic measurements to be made in regions found impossible using bonded quartz transducers. Measurements of C 11 in Tb as a function of magnetic field are presented to demonstrate their performance.

A High Resolution and Low Volume Ultrasonic Resonator Method for Fast Chemical Relaxation Measurements

AbstractA resonator cell technique with two quartz transducers for relative ultrasonic measurements in small liquid samples of about 1 to 5 ml is described. The three dimensional wave propagation in the cell is investigated by solving the wave equation under appropriate boundary conditions. On this basis relations are derived which allow a computer aided evaluation of the ultrasonic absorption as well as the propagation velocity in the liquid with an as yet unattained accuracy of about 2 parts in 105 within the frequency range of 400 kHz to 36 MHz. The method is particularly useful for the kinetic analysis of very fast chemical reactions. Its high resolution is demonstrated with aqueous solutions of MnSO4 and imidazole/maleic acid, respectively.

Stability analysis of model PSPP-80 quartz transducers

Stability analysis of model PSPP-80 quartz transducers

Properties of indium antimonide thin films as fast-response pressure transducers

Results are presented of studies on the application of InSb thin films for measuring rapidly varying pressures up to 600 atm in liquid non-conducting media. A comparison is made between this transducer and the quartz pressure transducer used as devices for measuring rapidly varying pressures. The dynamic error in a pressure-measuring system which included an indium antimonide thin film resistance transducer has been determined as less than 1.5%.

New acoustic resonator for liquids in the 0.2− to 2−MHz range

A new acoustic resonator with nonplanar quartz transducers for liquids (sample volume about 20 ml) in the 0.2− to 2−MHz range is described. The application of static overpressure onto the liquid cavity causes concave bending of both quartz transducers. This reduces loss contributions from diffraction and ’’side−wall effects’’ considerably, resulting in higher Q values for this resonator; moreover, air inclusions in the cavity are suppressed. Subject Classification: 35.24, 35.80.

Loading transducers for non-destructive testing and signal processing by acoustic bulk waves

Non-destructive testing and signal processing with acoustic bulk waves require the use of loaded transducers having a large bandwidth. The technique of loading quartz or ceramic transducers by backing with a material having a relatively large acoustic impedance is well known. A brief review of the methods and results of this classical type of loading is given. Another method of broadening the bandwidth by backing the transducer with one or several metallic layers of variable thickness followed by a semi-infinite medium is then proposed. A brief mention is also given to the technique of matching the backed transducer to the propagating medium. Several practical examples illustrating the use of the methods are given.

Equations of state and shock-induced transformations in solid I-solid II-liquid bismuth

An equation of state is determined for each phase in the solid I-solid II-liquid region of bismuth. Equality of the Gibbs free energy for each pair of phases determines the phase boundaries and triple point in the temperature-pressure plane. From the complete equation of state, the shock-wave response of bismuth preheated to 493 °K. is calculated and comparison is made with experimental data obtained by means of quartz transducer instrumentation. These results suggest that bismuth undergoes a certain degree of melting on the microsecond time scale of the shock-wave experiment. This is contrary to previous results and conclusions drawn from data on the shock-wave propagation in bismuth. These seemingly contradictory results may be due to microstructural differences in the samples or to differences in measuring techniques.

Ferrite Films for Shear and Surface Elastic Wave Transducer

Magnetostrictive Ni0.837Cu0.148Co0.015Fe2.000O4 ferrite films 10–60 μ thick were prepared on alumina and sapphire plates by vacuum-arc evaporation and by cathodic sputtering. The films of 30-μ thickness deposited on a sapphire rod, generated and detected 50-MHz shear waves by operation in conjunction with a quartz transducer. A commercial cubic magnet, of subcentimeter size, applied a bias field sufficient to operate the films. On the other hand, the films of 40-μ thickness sputtered on an alumina plate with eight-turn meander line on their surfaces generated and detected 10.8-MHz (wavelength 400 μ) surface elastic waves. It was unnecessary to apply any external bias field to operate the films, due to the use of a large internal stress induced in them during the heat treatment. Consequently, the deposited and the sputtered ferrite films can be applied to the shear and surface elastic wave transducers, respectively.