251.331 Saturation magnetization of spherical specimens 251.341 FMR linewidth and gyromagnetic ratio--251.401 Microwave surface conductivity-- Radio Frequency Standards 252.110 Coaxial connectors 252.120 252.810 252.811 252.812 Suggested calibration frequencies (waveguide)--- Voltage Attenuator-thermoelement voltmeters Rf millivoltmeters and rf signal sources252.813 Rf micropotentiometers 252.820 Power Coaxial rf calorimeters and rf powermeters 252.821 Coaxial bolometer units- 252.822 Coaxial bolometer-coupler units Waveguide bolometer units-- 252.920 252.921 Waveguide bolometer-coupler units 252.833 252.834 252.930 252.931 VSWR and impedance phase angle measurements Coaxial terminations, reflection coefficient magnitude -- Nonreflecting waveguide ports Attenuation 252.840 Coaxial fixed attenuators 252.841 Coaxial variable attenuators 252.842 252.843 252.844 Coaxial, waveguide-below-cutoff (piston) attenuators- 252.940 Fixed waveguide attenuators-- Frequency stability of signal sources 252.861 Power spectral analysis of signal sources 252.960 Cavity wavemeters, coaxial terminations252.961 Cavity wavemeters, waveguide terminations Pulse 252.870 Coaxial peak pulse powermeters 252.871 Coaxial peak pulse voltmeters and pulse generators 7.64 7.66 7.67 8.1 9.1 9.5 ist of Publications and Order Blank ost-card Request for Future Supplements last page OF THE NATIONAL BUREAU OF STANDARDS PART 1-GENERAL The text of Part 1 restates the policies and procedures relating to the National Bureau of Standards' measurement services, including calibrations and tests. It follows closely the language of Part 200 of Subchapter A, Chapter II, Title 15, of the Code of Federal Regulations. That issuance in the Federal Register of December 29, 1967, pursuant to the authority contained in 15 U.S.C. 275a and 277, incorporates by reference the full text of NBS Miscellaneous Publication 250 (MP 250), "Calibration and Test Services of the National Bureau of Standards." 200.100 Statutory functions. (a) The National Bureau of Standards has been assigned the following functions (15 U.S.C. 271-278e): (1) The custody, maintenance, and development of the national standards of measurement and the provision of means and methods for making measurements consistent with those standards, including the comparison of standards used in scientific investigations, engineering, manufacturing, commerce, and educational institutions with the standards adopted or recognized by the Government. (2) The determination of physical constants and properties of materials when such data are of great importance to scientific or manufacturing interests and are not to be obtained with sufficient accuracy elsewhere. (3) The development of methods for testing materials, mechanisms, and structures and the testing of materials, supplies, and equipment, including items purchased for use of government departments and independent establishments. (4) Cooperation with other governmental agencies and with private organizations in the establishment of standard practices, incorporated in codes and specifications. (5) Advisory service to government technical problems. agencies on scientific and (6) Invention and development of devices to serve special needs of the Government. a (b) The calibration and testing activities of the Bureau stem from the functions in paragraphs (a) (1) and (3) of this Section. These activities are assigned primarily to the NBS Institute for Basic Standards. Its program provides the central basis within the United States for complete and consistent system of physical measurement; coordinates that system and the measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. (c) The provision of standard reference materials for sale to the public is assigned to the Office of Standard Reference Materials of the NBS Institute for Materials Research. It evaluates the requirements of science and industry for carefully characterized reference materials, stimulates the Bureau's efforts to develop methods for production of needed reference materials, and directs their production and distribution. For information on standard reference materials, see Subchapter B, Chapter II, Title 15, of the Code of Federal Regulations. (d) The provision of technical services to facilitate technical innovation and industrial use of the results of modern science and technology is assigned to the NBS Institute for Applied Technology. The principal elements of the Institute are: (1) a Center for Computer Sciences and Technology which conducts research and provides technical services designed to improve cost effectiveness in the conduct of agency programs through the use of computers and related techniques; (2) technical divisions which provide services in technology of more general applicability; and (3) the Clearinghouse for Federal Scientific and Technical Information which promotes widest effective use by the scientific community, industry, and commerce of current information in all fields of industrial technology. 200.101 Measurement research. (a) The NBS Institute for Basic Standards carries out the Bureau's functions in developing an adequate national system of physical measurement and in providing related calibration services. Its staff continually reviews the advances in science and the trends in technology, examines the measurement potentialities of newly discovered physical phenomena, and uses these to devise and improve standards, measuring devices, and measurement techniques. As new requirements appear, there are continual shifts of program emphasis to meet the most urgent needs for the measurement of additional quantities, extended ranges, or improved accuracies. (b) The basic research and development activities of NBS are funded primarily by direct appropriations and are aimed at meeting broad general needs. Also the Bureau may undertake investigations or developments to meet some specialized physical measurement problem of another government agency, industrial group, or manufacturing firm, using funds supplied by the requesting organization. (a) An international treaty, the Metric Convention, was signed by 18 countries in 1875. In 1893 the United States established prototype No. 27 of the international meter bar and prototype No. 20 of the international kilogram as United States Prototype Standards for length and mass. Representatives of many of the 40 nations now adhering to this treaty meet periodically, in the General Conference of Weights and Measures, to consider detailed proposals concerning international standards for physical measurement. Successive Conferences now have agreed to adopt six units to serve as a practical base for an International System of Units (Systeme International d'Unités, abbreviated SI) --kilogram, meter, second, kelvin, ampere, and candela. These are arbitrarily chosen but precisely defined magnitudes of six physical quantities--mass, length, time, temperature, electric current, and luminous intensity, respectively--which are assigned unitary value in the International System. Because the system is coherent, the expressions for the other quantities of science and technology derived from these six through the equations of physics will have unitary coefficients also. The units of the English system--pound, inch, second, degree Fahrenheit, etc.--and of other systems of units are related SI units by agreed-upon conversion factors; see NBS Handbook 102, "ASTM Metric Practice Guide."'* to the *For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington, DC 20402. 40 cents. |