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Ultrasonic impedance matching from solids to gases
EL’PINER
I.E.
Physico-chemical reactions or the synthesis of biologically active agents can be controlled by ultrasound. Collapse of cavitational bubbles dissociates the molecules into their monatomic constituents or produces ions. Dissociation occurs even at relatively low irradiation intensities and difficult or even impossible reactions take place at normal temperatures and pressures. In biology ultrasonics facilitate the study of the interaction of structure and function of macromolecules, the study of protein structure and the synthesis of antibiotics. (8 figures) (Ultrasonics 1966, abstract
A. et d. An uhasonic light deflection system.
KORPEL,
in molecular biology. Priroda, No. 8, 20 (1965)
Ultrasound
443)
Transactions of the Institute of Electrical and Electronic Engineers Professional Group on Quantum Electronics, QE-1, No. 1, 60 (1965)
Constructional details and performance of an experimental light deflection system are given. It employs the Bragg reflection produced by ultrasonic waves in water and is in good agreement with theory. Seventy resolvable points can be obtained by varying the sound frequency between 40 MC/S and 45 MC/S. Linear scanning systems and the effects of attenuation across the aperture are considered and improvements in transducer design to obtain larger scanning angles are discussed. (2 figures, 3 references) (Ultrasonics 1966, abstract
HICKMAN,
R. G.
The influence of ultrasonic agitation on porosity of nickel electroplates. Plating, 52, No. 6, 540 (1965) Intense ultrasonic agitation of Watts baths decreases the porosity of nickel plating by 95x, whilst the optimum current density can safely be increased by 2-4 times. The origin of porosity and the probable mechanism by which ultrasonic agitation minimises the growth of pores are discussed. The experiments were conducted under stringent control, samples made in triplicate and the results were reproducible. A Westinghouse 500 W Magnopack working at 20 kc/s in 1.5 gal cleaning tank was used to produce the uniform cavitational field. (2 tables. 5 references) I (Ultrasonics . 1966, abstract 444) ’ ’
J. E. and RUOFF, A. L. Velocity of sound measurements in liquid metals. Review of
HILL,
Scientific Instruments,
36, No. 10, 1465 (1965)
A pulse-echo comparison technique can be used to determine the velocity of ultrasound in liquid metals to within & 0.01%. The apparatus consists of two identical cells. One contains mercury and the other, which has an external heater, contains the metal under study. An x-cut 5 MC/S quartz crystals and a micrometer coupled movable reflector was immersed into each cell. The effects of temperature were studied and the difficulty of satisfactory coupling of ultrasound at the transducer/liquid-metal and liquid-metal/reflector interfaces was overcome. Results of measurements by this apparatus in liquid indium are given and an improved fused quartz liquid-metal cell is proposed. (14 figures, 10 references) (Ultrasonics 1966, abstract 445)
KRAUTKRAMER,
Presentation Materials
447)
H.
and computing
Research,
of ultrasonic
data.
Applied
4, No. 4, 233 (1965)
The author analyses the information content of ultrasonic pulse-echo techniques and how some of it can be applied in statistical quality control. Principles, advantages and limitations of A-, B- and C-scan methods as well as of attenuation measurements and recording are discussed. A proposed automatic testing installation called “Differentiated data processing and plotting” is described. It can determine the positions of flaws, the defective section and the pattern of flaws. Sections of tested materials are graded on scaled digital information paper. (6 figures) (Ultrasonics 1966, abstract 448)
LUBE,
V. M.
Ultrasonic
et d. method of testing basic technological
in sugar beet industry. No. 4, 8 (1965)
Sacharnaya
processes Promishlenost, 39,
Continuous monitoring of physico-chemical processes in sugar refining is possible by ultrasonics. The state of the process can be computed from the measured ultrasound velocities in the media or the display calibrated directly in process variables. The velocity of ultrasound varies during the various manufacturing stages and is dependent on the fibre content, concentration and temperature. In industrial conditions and temperature, accuracies of the order of f O-1 % are claimed: the method should be adaptable to other industries. (1 table, 6 figures, 5 references) (Ultrasonics 1966, abstract 449)
LYNNWORTH,
L. C.
impedance matching from solids to gases. Institute of Electrical and Electronic Engineers. Transactions on Sonics and Ultrasonics, SU-12, No. 2, 37 (1965)
Ultrasonic and HAGEMAIER, D. J. Relationship of standards and specifications to NDT. Materials Evaluation, 23, No. 8, 377 (1965) As there is no general agreement on standards even within any one particular branch of non-destructive testing, the problem becomes acute when two or more methods have to be used simultaneously. In this paper the authors discuss the importance of standards, the different methods of NDT, and the definition of terms and specifications. They describe the ultrasonic pulse-echo and resonance methods and discuss the use of flat bottomed holes and step-wedge standards in the hope of stimulating discussion with the aim of producing united interdisciplinary specification and reference. standards. (3 figures, 1 reference) (Ultrasonics KLEINT
R. E.
1966, abstract 446)
By using probes with impedance matching layers the transmission of ultrasound from solids into gases in the low megacycle frequency range can be increased to practical proportions. The matching layers can be a resonant, a non-resonant or a composite water column. In the probe described the water acts both as a variable thickness layer and as a cooling medium in high temperature applications. When the water is thick h/4 contained by the membrane cover plate and is working in pulsed operation, transmission gains of 16 dB have been achieved. Theoretical gain for these probes is of the order of 21 dB but methods are proposed for increasing it to 40 dB. (13 figures, 31 references) (Ultrasonics 1966, abstract 450)
ULTRASONICS/h?lZ4UQ’
1966
I.E.
Physico-chemical reactions or the synthesis of biologically active agents can be controlled by ultrasound. Collapse of cavitational bubbles dissociates the molecules into their monatomic constituents or produces ions. Dissociation occurs even at relatively low irradiation intensities and difficult or even impossible reactions take place at normal temperatures and pressures. In biology ultrasonics facilitate the study of the interaction of structure and function of macromolecules, the study of protein structure and the synthesis of antibiotics. (8 figures) (Ultrasonics 1966, abstract
A. et d. An uhasonic light deflection system.
KORPEL,
in molecular biology. Priroda, No. 8, 20 (1965)
Ultrasound
443)
Transactions of the Institute of Electrical and Electronic Engineers Professional Group on Quantum Electronics, QE-1, No. 1, 60 (1965)
Constructional details and performance of an experimental light deflection system are given. It employs the Bragg reflection produced by ultrasonic waves in water and is in good agreement with theory. Seventy resolvable points can be obtained by varying the sound frequency between 40 MC/S and 45 MC/S. Linear scanning systems and the effects of attenuation across the aperture are considered and improvements in transducer design to obtain larger scanning angles are discussed. (2 figures, 3 references) (Ultrasonics 1966, abstract
HICKMAN,
R. G.
The influence of ultrasonic agitation on porosity of nickel electroplates. Plating, 52, No. 6, 540 (1965) Intense ultrasonic agitation of Watts baths decreases the porosity of nickel plating by 95x, whilst the optimum current density can safely be increased by 2-4 times. The origin of porosity and the probable mechanism by which ultrasonic agitation minimises the growth of pores are discussed. The experiments were conducted under stringent control, samples made in triplicate and the results were reproducible. A Westinghouse 500 W Magnopack working at 20 kc/s in 1.5 gal cleaning tank was used to produce the uniform cavitational field. (2 tables. 5 references) I (Ultrasonics . 1966, abstract 444) ’ ’
J. E. and RUOFF, A. L. Velocity of sound measurements in liquid metals. Review of
HILL,
Scientific Instruments,
36, No. 10, 1465 (1965)
A pulse-echo comparison technique can be used to determine the velocity of ultrasound in liquid metals to within & 0.01%. The apparatus consists of two identical cells. One contains mercury and the other, which has an external heater, contains the metal under study. An x-cut 5 MC/S quartz crystals and a micrometer coupled movable reflector was immersed into each cell. The effects of temperature were studied and the difficulty of satisfactory coupling of ultrasound at the transducer/liquid-metal and liquid-metal/reflector interfaces was overcome. Results of measurements by this apparatus in liquid indium are given and an improved fused quartz liquid-metal cell is proposed. (14 figures, 10 references) (Ultrasonics 1966, abstract 445)
KRAUTKRAMER,
Presentation Materials
447)
H.
and computing
Research,
of ultrasonic
data.
Applied
4, No. 4, 233 (1965)
The author analyses the information content of ultrasonic pulse-echo techniques and how some of it can be applied in statistical quality control. Principles, advantages and limitations of A-, B- and C-scan methods as well as of attenuation measurements and recording are discussed. A proposed automatic testing installation called “Differentiated data processing and plotting” is described. It can determine the positions of flaws, the defective section and the pattern of flaws. Sections of tested materials are graded on scaled digital information paper. (6 figures) (Ultrasonics 1966, abstract 448)
LUBE,
V. M.
Ultrasonic
et d. method of testing basic technological
in sugar beet industry. No. 4, 8 (1965)
Sacharnaya
processes Promishlenost, 39,
Continuous monitoring of physico-chemical processes in sugar refining is possible by ultrasonics. The state of the process can be computed from the measured ultrasound velocities in the media or the display calibrated directly in process variables. The velocity of ultrasound varies during the various manufacturing stages and is dependent on the fibre content, concentration and temperature. In industrial conditions and temperature, accuracies of the order of f O-1 % are claimed: the method should be adaptable to other industries. (1 table, 6 figures, 5 references) (Ultrasonics 1966, abstract 449)
LYNNWORTH,
L. C.
impedance matching from solids to gases. Institute of Electrical and Electronic Engineers. Transactions on Sonics and Ultrasonics, SU-12, No. 2, 37 (1965)
Ultrasonic and HAGEMAIER, D. J. Relationship of standards and specifications to NDT. Materials Evaluation, 23, No. 8, 377 (1965) As there is no general agreement on standards even within any one particular branch of non-destructive testing, the problem becomes acute when two or more methods have to be used simultaneously. In this paper the authors discuss the importance of standards, the different methods of NDT, and the definition of terms and specifications. They describe the ultrasonic pulse-echo and resonance methods and discuss the use of flat bottomed holes and step-wedge standards in the hope of stimulating discussion with the aim of producing united interdisciplinary specification and reference. standards. (3 figures, 1 reference) (Ultrasonics KLEINT
R. E.
1966, abstract 446)
By using probes with impedance matching layers the transmission of ultrasound from solids into gases in the low megacycle frequency range can be increased to practical proportions. The matching layers can be a resonant, a non-resonant or a composite water column. In the probe described the water acts both as a variable thickness layer and as a cooling medium in high temperature applications. When the water is thick h/4 contained by the membrane cover plate and is working in pulsed operation, transmission gains of 16 dB have been achieved. Theoretical gain for these probes is of the order of 21 dB but methods are proposed for increasing it to 40 dB. (13 figures, 31 references) (Ultrasonics 1966, abstract 450)
ULTRASONICS/h?lZ4UQ’
1966