摘要:

A flowmeter system is described which gives continuous readings of flow velocity, with a fast rate of response. The ``upstream‐downstream'' method is used in which velocity of a fluid is determined by measuring the phase difference between an upstream and downstream ultrasonic wave of, say, 100 000 cycles. The functions of the transmitting and receiving transducers are interchanged at a fast rate, say 100 cycles per second, allowing the use of a synchronous rectifier. In this way, no long time stability of the phasemeter is required so that very small flow rates can be measured. Velocities as low as 0.1 cm/sec were successfully measured. A special commutator switch with very low transfer capacitance and, as an alternative, an electronic switch are described. The transducers used are barium titanate crystals mounted in a manner so that their contact with the fluid is avoided.

ISSN:0034-6748    

DOI:10.1063/1.1771023

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

An instrument is described which makes possible universal evaluation of time‐displacement records with regard to velocity and kinetic energy, acceleration and accelerating force, time, and displacement. It consists of a measuring device for reading distances, angles, and second derivatives, and a slide rule for direct conversion of the measured values into the desired values. The instrument can be attached to a standard drafting machine of a drawing board. It has many advantages over the present methods of evaluation; no lines need to be drawn on the record, and the instrument permits much more rapid evaluation with fewer errors and can be used by less highly trained personnel.

ISSN:0034-6748    

DOI:10.1063/1.1771024

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

The process of generating millimeter microwave energy from a crystal multiplier driven by a reflex klystron is discussed. Quantitative data are given on the intensity of the various harmonics down to a wavelength of 1.9 mm. A harmonic generator of novel construction which has proven superior to the previously used types is described, and the details of our version of a built‐in crystal detector are given.

ISSN:0034-6748    

DOI:10.1063/1.1771025

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

A new technique for the calibration of static, differential pressure sensing devices is described. The system of calibration is explained and the necessary equations are developed in detail. The basis of this technique for producing known values of very small static pressure differences is that of the air centrifuge. This method has been employed for developing pressure differences as small as 10−6psi.

ISSN:0034-6748    

DOI:10.1063/1.1771026

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

The primary considerations which were employed in the design of a cloud chamber for a recent experiment were to incorporate into its characteristics as high a magnetic field strength and as short a cycle time as practical, and a sequencing control circuit which would be both simple to adjust and reliable over long periods of data‐taking time. A description is given of the important constructional details of the cloud chamber as well as a discussion of the more important auxiliary circuits. These are: the control circuits for the diesel‐driven generator which supplies the current for the cloud‐chamber field coils, the pulsed light system for photographic illumination, and the temperature regulating circuit for the cloud chamber.

ISSN:0034-6748    

DOI:10.1063/1.1771027

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

The method and apparatus are described for determining velocities of detonation over one to five adjacent segments of an explosive charge. Time intervals are determined to the nearest 0.1 microsecond, which permits an accuracy of the order of 1 percent where distances of 10 centimeters are employed in 7000 m/sec explosives. Representative data are included to show the accuracy of the method as well as application techniques.

ISSN:0034-6748    

DOI:10.1063/1.1771028

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

A parallel‐plate chamber with electrode separation variable from 2 mm to 2 cm has been used to measure recombination, attachment, and energy resolution for beta‐ray ionization in liquid argon. A collecting voltage up to 30 kv was used without introducing spurious pulses. Amplifier noise sets the lower limit to beta‐ray detection at about 150 kev and limits the energy resolution to about 100 kev (full width at half maximum at any energy).

ISSN:0034-6748    

DOI:10.1063/1.1771029

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

A description is given of apparatus used to measure the heat capacity of metal wires by pulsed heating. The electrical energy supplied to the wire is determined with respect to a platinum standard while the temperature rise is determined from the change in resistance and the measured temperature coefficient of resistance. A maximum error of 5 percent in the specific heat might be expected with the apparatus as built, but the results agree with most published data to within a few percent in the range 0°C to 650°C.

ISSN:0034-6748    

DOI:10.1063/1.1771030

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

The transit time of an electron between the cylinder and the central wire of a self‐quenching Geiger counter has been measured as a function of several counter parameters. The partial pressure, total pressure, and nature of the filling mixture were varied. The measured times are presented in graphic form.

ISSN:0034-6748    

DOI:10.1063/1.1771031

出版商:AIP    

年代:1954

数据来源: AIP

摘要:

A pressure‐sensitive element is described which provides an electrical output proportional to the pressure difference existing on the two sides of the element. By means of an electrically conducting lead in each arm of a U‐tube manometer the liquid (mercury) represents the contact point of a potentiometer; under the influence of an applied pressure this contact point is moved electrically. In the application described, the variation of light intensity at a point in the fringe system of an optical interferometer is calibrated as a function of density or pressure changes occurring in one of the interfering light beams.

ISSN:0034-6748    

DOI:10.1063/1.1771032

出版商:AIP    

年代:1954

数据来源: AIP