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The National Bureau of Standards is engaged in fundamental and applied research in physics, chemistry, mathematics, and engineering. Projects are conducted in fifteen fields: electricity and electronics, optics and metrology, heat and power, atomic and radiation physics, chemistry, mechanics, organic and fibrous materials, metallurgy, mineral products, building technology, applied mathematics, data processing sys tems, cryogenic engineering, radio propagation, and radio standards. The Bureau has custody of the national standards of measurement and conducts research leading to the improvement of scientific and engineering standards and of techniques and methods of measurement. Testing methods and instruments are developed; physical constants and properties of materials are determined; and technical processes are investigated.
Journal of Research
The Journal presents research papers by authorities in the specialized fields of physics, mathematics chemistry, and engineering. Complete details of the work are presented, including laboratory data experimental procedures, and theoretical and mathematical analyses. Annual subscription: domestic, $4.00; $1.25 additional for foreign mailing.
Technical News Bulletin
Summaries of current research at the National Bureau of Standards are published each month in the Technical News Bulletin. The articles are brief, with emphasis on the results of research, chosen on the basis of their scientific or technologic importance. Lists of all Bureau publications during the preceding month are given, including Research Papers, Handbooks, Applied Mathematics Series, Building Mate rials and Structures Reports, Miscellaneous Publications, and Circulars. Each issue contains 12 or more two-column pages; illustrated. Annual subscription: domestic, $1.00; 35 cents additional for foreign mailing.
Basic Radio Propagation Predictions
The Predictions provide the information necessary for calculating the best frequencies for communication between any two points in the world at any time during the given month. The data are important to all users of long-range radio communications and navigation, including broadcasting, airline, steamship, and wireless services, as well as to investigators of radio propagation and ionosphere. Each issue, covering a period of one month, is released three months in advance and contains 16 large pages, including pertinent charts, drawings, and tables. Annual subscription: domestic, $1.00; 25 cents additional for foreign mailing.
CATALOGS OF NBS PUBLICATIONS
National Bureau of Standards Circular 460 and its Supplement lists all Bureau publications from 1901 through June 1952, including Applied Mathematics Series, Building Materials and Structures Reports, Circulars, Handbooks, Research Papers, and Miscellaneous Publications. Brief abstracts for the publications issued after January 1, 1942, are also included.
National Bureau of Standards Circular 460, 375 pages, $1.25. Supplement to Circular 460, 223 pages, 75 cents. (A free mimeographed list of publications issued since June 1952 is available on request to the National Bureau of Standards.)
Order all publications from the Superintendent of Documents
U. S. Government Printing Office, Washington 25, D. C.
A Survey of Properties, Applications, and Production Methods
Nancy J. Tighe
Fused-silica fibers have an important function in many measuring instruments used in scientific research. Much of the information on the production and fabrication methods and on the properties of the fibers is widely scattered throughout the technical literature. This Circular is a survey of this literature and a summary of the findings. A bibliography of pertinent references on the subject is included to provide the sources of more complete and detailed information necessary for specific applications.
This Circular is the result of a literature survey covering the properties and the uses of fused-silica fibers. Silica fibers or, as they are frequently called, quartz fibers, have had wide application in precision measuring instruments despite the fact that the factors which affect their behavior are not fully known. The survey of the literature revealed that while some investigations are made in order to obtain specific values of particular properties, other studies are made primarily to develop more completely the theoretical treatment of glasses and their relation to liquids and solids. Although this Circular covers primarily those properties related to the actual use of the fibers, it mentions those theories and properties needed for better understanding of the variations observed in the testing and use of silica fibers. It is hoped that this summary will aid in the production of silica fibers having more reproducible and predictable properties.
Throughout the literature such terms as fused silica, fused quartz, vitreous silica, silica glass, quartz glass are used to refer to types of fused silica. The use or misuse
of the terms has been discussed frequently [7, 112, 301, 303 to 305] but little uniformity has resulted. The terms used are meant to indicate the degree of transparency or the source of the raw material. For instance, in the glass industry the term fused silica may refer to the transparent material formed by the fusion of quartz sand or other forms of silica, while the term fused quartz may refer to the transparent material formed by the fusion of pure quartz rock crystal. However, this designation of terms is not used consistently, for the material is frequently described as clear or translucent fused quartz or as clear or translucent fused silica. In this Circular the term fused silica will be used in general for that glass formed by the fusion of silica. Where necessary, this term is modified by the adjectives clear or translucent. For instance, where the condition of transparency is evident from the use, such as in fibers which are drawn from clear fused silica, the fibers are referred to simply as silica fibers.
1 Figures in brackets refer to the references listed in the bibliography.