摘要:

The weathering characteristics of cotton duck treated with copper or zinc naphthenate containing mercury naphthenate or phenyl mercury naphthenate, and the effect of weathering on the rotproofing efficacy of these treatments as judged by the soil burial method, have been investigated. The presence of the mercury compounds reduced the loss of copper during burial and did not affect the weathering properties of the treated fabrics.In an investigation of the rotproofing efficacy of binary mixtures, the naphthenates of cadmium, chromium, copper, iron, lead, mercury, silver, and zinc, containing a total of 0.2% metal, showed in general greater resistance to attack during soil burial than did samples containing the same percentage of metal in the form of single naphthenates. Ternary mixtures of the naphthenates of cadmium, copper, lead, mercury, silver, and zinc, applied to cotton fabric in equivalent concentration of total metal, were in general more effective than the binary mixtures of the same compounds.

ISSN:1923-4287    

DOI:10.1139/cjr47f-025

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

A butt-welding apparatus employing a condenser discharge is described. This apparatus was developed for welding thermocouples of small dimensions but is suitable for most types of fine wires. The welding characteristics and possible applications are given in detail.

ISSN:1923-4287    

DOI:10.1139/cjr47f-026

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Three models of portable Geiger–Müller counters which were found useful in the detection of radioactive minerals are described. The models are similar in that in each the high voltage for the Geiger–Müller counter tube is supplied by means of a multivibrator circuit and the pulse from the G–M tube is fed to a trigger circuit which actuates headphones. In one model a neon tube discharge circuit is used to give one headphone pulse for every 10 from the G–M tube and a counting rate meter is provided. Details of circuit design and application are given. The circuit of a simple amplifier that may be used with a G–M tube at the end of a long three-conductor cable is given.

ISSN:1923-4287    

DOI:10.1139/cjr47f-027

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

A laboratory shaker is described that employs an eccentricless drive. The machine has sufficient flexibility in design to permit variable temperature and speed control. It has a capacity of two dozen 500-ml. flasks.

ISSN:1923-4287    

DOI:10.1139/cjr47f-028

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The measurement of the diameters of cylinders and cones is an important feature in gauge manufacture and inspection. High accuracy is essential in this work, as the objects measured may be employed as limit gauges for use in the inspection of other precision gauges to which direct means of measurement cannot be applied. A comparator for accommodating cylinders or cones with maximum diameters of 12 in. and lengths up to 48 in. was designed and constructed during Great War II at the National Research Laboratories, Ottawa, and used throughout the war. In preparing the design special consideration was given to ease of construction and no ultra precision grinding or difficult fits were involved.

ISSN:1923-4287    

DOI:10.1139/cjr47f-029

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

This paper describes an interferometer designed for the determination of the parallelism of the working faces of end-gauges up to 24 in. in length. An instrument for this purpose, but which required somewhat highly specialized technique in the course of its construction, had been previously designed by the National Physical Laboratory. Using optical principles the same as those of the British instrument, another of an entirely new mechanical design has been constructed by the National Research Laboratories, Ottawa. This new interferometer incorporates kinematic principles and a number of interesting features to permit easy adjustment and operation to the very fine limits necessary. By the addition of a sensitive level vial to this instrument, the difference in length of nominally equal end-gauges can be determined to an accuracy of 1 or 2 × 10−6 in.

ISSN:1923-4287    

DOI:10.1139/cjr47f-030

出版商:NRC Research Press    

年代:1947

数据来源: NRC