Four groups of new methods of indirect ultrasonoscopy and ultrasonography are developed: those using temperature-sensitive chromotropic compounds, those using leucobases of dyes, those using thermo-stimulable phosphors, and those using special temperature-sensitive phosphors. Various techniques are described and some results shown in the illustrations. Finally, a new method of direct ultrasonography is proposed. This method makes use of the possibility to detonate certain labile chemical compounds by ultrasonics.N the ultrasonographic investigations, on which the first named author • reported in a previous issue of the Journal, serious difficulties arose from the heat developed in the ultrasonic field unless careful precautions were taken. Therefore, it was very natural to try whether methods of indirect ultrasonoscopy and/or ultrasonography could be developed with the heat effect as the primary effect. In what follows a concise account is given of a series of successful experiments conducted chiefly although not exclusively along this line and some illustrative results are shown.In Table I the various methods of ultrasonoscopy and ultrasonography discussed in this paper are classified and tentatively named with reference to the recording material. A. CHROMOTROPIC METHODS a. Thermo-Chromotropic MethodIn thermo-chromotropic methods substances are applied which change their colors upon heating. They are designated as temperature-sensitive chromotropic compounds and especially as reversibly-chromotropic, if they possess the property of regaining their original colors on cooling down to their initial temperatures.Among the reversibly-chromotropic compounds used in the experiments under discussion here mercury silver iodide had the greatest temperature-sensitivity. This substance was made according to Rosenberg's 2 direc-* Presented at the 42nd meeting of the Acoustical Society of America, Chicago, October 23, 1951. • This paper represents an essential part of a thesis submitted by the second named author to . The recipe reads translated from German:Dissolve 17 g of silver nitrate in about 150 cm s of distilled water and also 16.6 g of potassium iodide in 150 cm a of distilled water. Mix both solutions well in a flask. Filter off the yellow precipitate of silver iodide, wash it thoroughly on the filter paper with distilled water, and allow both the filter and the residue on it to dry in a dark place. Dissolve 13.6 g of mercuric chloride in about 400 cm 3 of distilled water and add a solution of 16.6 g of potassium iodide in 100 cm s of distilled water. Filter off the deep-red precipitate of mercuric iodide, wash it thoroughly on the filter paper with tions. The preparation was impasted, with nitrocellulose lacquer as a binder, on a sheet of stiff, thin, and glossy drawing paper and allowed to dry. Later a plastic film screen was made which gave better results than the paper screen.The chromotropic screen was irradiated ultrasonically and the hotter parts of the ultrasonic field, such as the focus of a concentration de...
This report describes a radio-control system for free-running models of surface ships. The system is designed for use in models ranging from approximately 15 to 30 feet in length and is arranged so that it may be used with single or multiscrew propulsion systems. A proportional rudder-control channel and two proportional propulsion-control channels are provided. Rudder position, rudder running time, and propulsion shaft rpm are indicated on the console to guide the operator in controlling the model. The system is powered by long-life rechargeable nickel-cadmium batteries. This report includes a brief review of the engineering study, and describes the complete system. Installation, operation and maintenance instructions, with photographs and schematic diagrams, are included. INTRODUCTION Free-running self-powered models of surface ships are used by the TMB Hydromechanics Laboratory for tests to determine and predict maneuverability characteristics of the ship. In the past these tests have been conducted in the J-shaped end of the main TMB towing tank. Power and control circuits to the model have been carried through a multiconductor cable or "drop-cord," supported by a movable boom which is manually operated to suspend the "dropcord" more or less directly over the model during the test maneuver. During the course of design of the new TMB Maneuvering and Seakeeping Facility now nearing completion, work was initiated to develop requirements and specifications for a completely free-running self-powered radio-controlled model system. Since the maneuvering basin in this facility is about 240 by 360 feet, it was felt that a moving boom and drop-cord would be impractical over an area of this size. The functional requirements 1 for the radiocontrol system were developed by the Stability and Control Division of the Hydromechanics Laboratory. The Instrumentation Division and the Facilities Division of the Industrial Department jointly conducted a feasibility and preliminary design study 2 of a system to meet these requirements and subsequently designed and constructed the complete control and powering system. References are listed on page VI-1.
The autoradiograph technique making use of carbon14 is useful in studying the carbon black distribution in rubber. It is superior to the photomicrographic technique in studying carbon black dispersion in rubber. Autoradiographs of different carbon black-rubber mixes (tensile strengths varying from 300 to 3300 pounds per square inch) showed visible variations in the carbon black distribution which closely agree with the tensile strength data, whereas photomicrographs of the same mixes showed no differences among the various mixes. The autoradiographic technique is also useful in tracking down carbon black agglomeration in rubber.
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