Ultrasonic Immersion Research Articles

An interactive computer program for analysis of ultrasonic modulus data on anisotropic materials

The program computes stiffness components, compliances and engineering elastic constants for composite materials, using velocity measurements taken from the ultrasonic immersion method. The method is applicable to transversely isotropic, tetragonal and orthotropic materials. A fully worked example is included.

Ultrasonic velocity measurement for the determination of density in polyethylene

AbstractAn ultrasonic immersion method is presented for the rapid and accurate measurement of longitudinal sound velocity (v) in polyethylene (PE). The method is based solely on the measurement of time delays and can be automated. The samples are the same press‐molded plaques that are prepared for the standard‐density (ρ) determination using a density‐gradient column, Our measurements on a representative group of various types of PE with densities in the range 0.92 to 0.96 g/cm3 show without ambiguity that v is proportional to ρ. The degree of correlation is such that we come to suggest that the acoustic method be used for the characterization of density. We show that the accuracy is good and compares with that of the density‐gradient column and we then conclude on the practical advantages of the ultrasonic method.

Some results on the resolution of small inclusions in ultrasonic immersion testing of steel with focussed probes

Results are presented for an analysis of ultrasonic signals reflected from small flaws (⩽ 1 mm) in steel samples during immersion testing with 10 MHz and 15 MHz focussed probes. A technique is introduced for setting up the working parameters in ultrasonic testing of flat specimens to take account of the position of inclusions relative to the focal zone, according to the thickness of the layer to be examined and the resolution required.

Atomic emission spectrometric analysis of airborne particulate matter by direct nebulization of suspensions into the inductively-coupled plasma

A method is described for the rapid, direct emission spectrometric determination of iron in airborne particulate matter collected on polystyrene fiber filters using a conventional high-volume sampler and a Japanese low-volume sampler. The suspension prepared by dissolving the filter material in xylene was directly nebulized into the inductivelycoupled plasma excitation source. An ultrasonic immersion device was used for stirring purposes. Particles within the size range 0.1–100 μm in diameter are collected on the high-volume filters, while the largest particles on low-volume filters do not exceed 10 μm in diameter. The difference in the particle size composition entailed the use of a separate set of standard suspensions for each sample type. Standard suspensions for calibration were prepared from NBS SRM-1648 (urban particulates) as originally received and from its ground powder for high-volume and low-volume samples, respectively. The relative standard deviation was usually below 5%, which is acceptable for large-scale air pollution survey work. The possibility of determining other major and minor elements in airborne particulate matter was also examined.

Ultrasonic investigations of a second bulk compressional wave in a porous solid

A second bulk compressional wave has been observed in water‐saturated porous solids using a transmission ultrasonic immersion technique. In this technique, the bulk modes are generated in a solid layer based on the concept of mode conversion and refraction at liquid‐solid interfaces. With this technique, the sound speeds of the normal compressional wave, shear wave, and second compressional wave were determined. The pulsed ultrasonic system incorporated commercially available pulser/receiver electronics and nondestructive testing type broadband transducers with a center frequency of about 1 MHz. The porous solids studied included samples composed of sintered glass spheres and samples from two types of commercially available filtration materials. The porosity of the samples ranged from 10%–40% and the fluid permeability ranged from 1–10 μm2 (i.e., 1–10 Darcy). Velocity data will be presented as a function of porosity and fluid permeability. The second compressional wave speed is approximately 25% of the normal compressional wave speed. The data will be interpreted in terms of the Biot theory of wave propagation in a fluid‐saturated porous solid [J. Appl. Phys. 28, 168–178 (1956)].

Sterilisation of teeth for homogenous transplantation

Sterilisation of teeth for homogenous transplantation has been successfully achieved by combined ultrasonic waves and immersion in 6 per cent hydrogen peroxide. This combined treatment was found to have no harmful effect on the tooth integrity as indicated by enamel solubility, hardness, root canal seal and tooth size and weight. It is suggested the method offers the possibility of storing teeth in a ‘tooth bank’.

High-speed measurement of the internal diameter of tubes: a comparison of methods

The authors have compared various methods of tube measurement and have made the striking conclusion that the continuous measurement of the internal diameter of precision tubes with an air gauge is often useless in practice. The methods selected for experiment were all contactless and so included only air-gauging techniques and the capacitive measurement system. The authors propose an improved air-gauging technique where the pressure transducer is close to the air nozzles thus increasing the measurement speed by 12 times. However, the capacitive method was found to be even faster as well as stable and accurate. The disadvantage with the capacitive method is the need to introduce a probe into the tube. This difficulty is avoided by an indirect method where both external diameter and wall thickness were found instead and the difference taken. The perfected system has now been combined with ultrasonic immersion testing for flaws to make a complete tube testing facility.

Ultrasonic Elastic Constants of Carbon Fibers and Their Composites

The elastic constants of carbon-fiber-reinforced composites have been measured with an ultrasonic immersion technique. Both carbon and graphite fibers were studied. These fibers were derived from both rayon and polyacrylonitrile (PAN), and had Young's moduli ranging from 6 to 80×106 psi. The composite elastic constants varied with fiber modulus and fiber type (carbon or graphite) but not with the fiber-matrix bond. The fiber elastic constants c11 and c66, corrected for porosity, varied with fiber modulus but not with fiber type. The fiber constants c44 and c13 were independent of fiber modulus but varied with fiber type.

Some characteristics of the operation of the ultrasonic immersion—resonance thickness meter): Kalinen, V.A., Pranitskii, A.A., (Sept–Oct 1967) no 5, p 363 (2181)

Some characteristics of the operation of the ultrasonic immersion—resonance thickness meter): Kalinen, V.A., Pranitskii, A.A., (Sept–Oct 1967) no 5, p 363 (2181)

Ultrasonic Immersion Equipment for Flaw Inspection of Steel Billets

水浸超音波探傷法は,探触子と被検査材が直接接触しないので鋼材の表面アラサなどの影響が直接法にくらべて少なく,超音波の送信,受信が安定して行なわれるという利点がある。そのために,鋼材内部欠陥の自動探傷に広く使用されている。昭和42年12月特殊鋼圧延鋼材の内部欠陥を自動的に検査することを目的として,大同製鋼(株)星崎工場に水浸超音波探傷装置が設置された。その後の操業実績から作業能率,検査精度などの点で従来の直接法と比較し優れていることが立証されたので,ここにその設備概要,直接法と比較した場合の特性の相異点および稼動初期の問題点について報告する。

A new concept in immersion ultrasonics: Materials Evaluation, Vol 26, No 5 (May 1968) pp 83–89

A new concept in immersion ultrasonics: Materials Evaluation, Vol 26, No 5 (May 1968) pp 83–89

Symmetrical scanning of the head with ultrasound using water coupling.

The determination of the absolute position of reflecting structures in the brain is difficult, owing to refraction of the ultrasonic beam and the different velocities of ultrasound in the skull and the brain. Since many brain disorders distort the symmetrical brain structures, emphasis has been placed more on the detection of asymmetries rather than on faithful mapping of the brain. The asymmetry can be displayed with adequate accuracy by symmetrical scanning of the head, simultaneously from both sides with two transducers. An ultrasonic immersion scanner that employs this technique is described, and some results are given.

Symmetrical Scanning of the Head with Ultrasound

The absolute position determination of reflecting targets in the brain is difficult because of the refraction of the ultrasonic beam and the different velocities in the bones of the skull and brain. Since many brain disorders distort the almost symmetrical brain structures, emphasis should be placed more on the detection of asymmetries rather than on faithful mapping of the brain. The asymmetry can be displayed with considerable precision by symmetrical scanning of the head simultaneously from both sides with two transducers. An ultrasonic immersion scanner that employs this technique will be described, and the results will be discussed.

Horizontal scanning of the head with ultrasound.

An ultrasonic immersion brain scanner is described and the method and results of examinations on 33 hospitalized patients are discussed. Reproduced in this article are scans, showing images most likely representing the inner skull-brain interface, the falx, 3rd ventricle, insula, and parts of the lateral ventricles, such as the anterior horns, bodies and trigones.