Report discussing measurements of viscosity made with relative viscometers. These instruments must be calibrated with liquids whose viscosities are known. NBS provides a series of 10 oils for this purpose. Their viscosities range from 0.02 to 450 poises and their temperature coefficients of viscosity range from 2.1 to 9.4 percent per degree C. The less viscous oils are more stable. Correction formulas for errors or conditions are presented.

Report describing the various systems of measurement used in the literature on electricity and magnetism, with respect to their units. Their historical development is summarized. The manner in which each is derived from either of the two alternative points of view of the experimentalist and the theoretician is compared and contrasted. Tables are included for the conversion of equations and numerical values from one system to another.

Report discussing the transient magnetic behavior of a paramagnetic substance, after an initial disturbance, considered theoretically for a variety of situations in which the lattice temperature rises as a result of energy flow from the magnetic (electron spin) system. Next, the opposite extreme is considered - that in which the resonant and remaining modes are totally uncoupled. Finally, there is a consideration of the case of spins coupled only to the resonant phonons, which in turn are coupled to a constant temperature bath, whether this be the helium or the remaining modes.

Report of a homogeneous set of intensity-related data calculated for 3288 spectral lines of Fe I in the region from 2100 to 9900 angstroms. The quantities tabulated in the present monograph include log (g__), log (gf), gf,f,gA, and A. Since recent investigations do not support excitations corrections in the case of Fe I and certain other spectra, the present tabulation incorporates a removal of that normalization function. This recalculation affects the values for all lines whose upper energy levels lie above 46000 cm -1 and should significantly improve the internal consistency of the present data.

Report combining National Bureau of Standards Monograph 27 with the references given in Supplement 1 (May 13, 1963) and issued as a single publication to assist users of this material. References concern the field of temperature measurement. These references were collected from two general sources: Scientific and technical literature and government reports. References are divided into a number of categories based on the type of instrument used. Some references to calibration of instruments and to scientific theories upon which temperature measurement is based are also presented.

Report presenting more than 500 references to the field of temperature measurement. These references were collected from two general sources: Scientific and technical literature and government reports. The period covered is from 1953 to June 1960, with some from earlier dates. References are divided into a number of categories based on the type of instrument used. Some references to calibration of instruments and to scientific theories upon which temperature measurement is based are also presented.

Report discussing variations in comparative tests of portland cements that could lead to the rejection of a material fully conforming to specification requirements, or the acceptance of a material with undesirable chemical or physical properties. Many of the causes for variation in chemical analyses and physical test results are listed in this discussion, and remedies for some of the more frequently encountered deficiencies in apparatus and methods are suggested.

Report discussing the problem of predicting dose rates and of estimating the effectiveness of shielding from radiations resulting from nuclear explosions. A number of calculations and supporting experiments regarding the penetration and diffusion of gamma rays, neutrons, and electrons through air and bulk materials are summarized. Indications are given of gaps in such input information. A selection of 485 references from the unclassified literature is presented, of which 388 are cataloged as to source geometry and energy, absorber material and configuration, type of data presented, and method of calculation or experimental technique. These cataloged references include radiation field studies ranging from the point-source infinite-medium situation up through such complicated geometries as foxholes, shelters, and conventional structures. The other references are of a general or review nature or contain input spectral data.

Report presenting graphs of the change in input impedance of electrically short dipole antennas in the presence of an isotropic and homogeneous ground which considers four types of antennas: horizontal and vertical, electric and magnetic dipoles. Curves of the change in both the input resistance and reactance are shown for a wide range of values of the frequency, antenna height above the ground, and electromagnetic ground constants.

Report documenting standard x-ray diffraction powder patterns for various compounds, intended to replace previous data or provide information for new substances. It describes the methods and, for each substance, outlines any previous data as well as information about the sample used and structural data, with a table of diffraction patterns.

Report documenting standard x-ray diffraction powder patterns for various compounds, intended to replace previous data or provide information for new substances. It describes the methods and, for each substance, outlines any previous data as well as information about the sample used and structural data, with a table of diffraction patterns.

Report giving tables of the linear contraction relative to 293 ºK, (L293ºLT)/L293, and the linear expansion coefficient, dL/L293dT, of thirty elements, forty-five alloys, twenty-two other inorganic substances and twenty plastics and elastomers in the temperature range, 0 to 300 ºK.

Report presenting a table of corrected optical pyrometer readings which enables optical pyrometer users to convert observed temperature immediately to the true temperature, if the effective emissivity of the material being observed is known. The table gives observed temperatures from 1,000 to 3,000ºK in increments of 5 degrees, from 3,000 to 5,000ºK in increments of 10 degrees, from 5,000 to 10,000ºK in increments of 50 degrees, and from 10,000 to 39,900ºK in increments of 100 degrees. For these, true temperatures are tabulated for 49 emissivities ranging from 0.02 to 0.98 in increments of 0.02.

Report is a text revision of the International Temperature Scale of 1948; the numerical values of temperatures remain the same. The adjective "Practical" was added to the name by the International Committee on Weights and Measures. The scale continues to be based upon six fixed and reproducible equilibrium temperatures to which values have been assigned, and upon the same interpolation formulas relating temperatures to the indications of specified measuring instruments. Some changes have been made in the text to make the scale more reproducible than its predecessor. The triple point of water, with the value 0.01 ºC replaces the former ice point as a defining fixed point of the scale. It is also recommended that the zinc point, with the value 419.505 ºC, be used instead of the sulfur point. The recommendations include new information that has become available since 1948.

Report reviewing the theoretical methods of optical pyrometry and the application of these methods at the National Bureau of Standards in realizing, maintaining and distributing the International Practical Temperature Scale above 1063 ºC is presented. In the theoretical presentation, the concepts of effective and mean effective wavelengths are introduced, and various equations relating these parameters to each other and other physical quantities are derived. The methods presentation discusses important features of precision visual optical pyrometers, experimental procedures, and results of primary and secondary calibrations of optical pyrometers.

Report presenting a bibliography on atomic transition probabilities. The papers are arranged according to elements and stages of ionization, and the method employed and class of transitions are indicated behind each reference. Only articles on discrete transitions, both permitted and forbidden, are listed. Also included is a supplementary list of papers dealing with transition probabilities from a general point of view, a table showing the availability of numerical material on the individual atoms and ions, and a table of conversion factors.

Report presenting a bibliography of about 550 references of the soft X-ray literature since 1950 and through 1960. The emphasis is on the application of soft X-ray spectroscopy to the study of valence band electronic states in metals and alloys. Therefore, the spectral region of 25 to 800 angstroms involving ruled glass grating spectrometers is of principal interest. In addition to soft X-ray data, references on all pertinent aspects of the apparatus and experimental problems are included. Also listed separately are references of value in corroborating soft X-ray data with other results. Subject, author, X-ray band, material, and other indices are included.

Report describing a gravimetric hygrometer that serves as the NBS standard instrument for the measurement of the moisture content of gases on an absolute basis in terms of mixing ratio (mass water vapor/ unit mass of dry gas). The National Bureau of Standards and other laboratory reference and working instruments are compared and calibrated with this instrument. The measuring operation involves the absorption of the water vapor from a water vapor-gas mixture by a solid desiccant and the determination of the mass of this water vapor by precision weighing; it also involves the determination of the volume of the associated gas of known density by counting the fillings of two calibrated stainless steel cylinders. The construction and operation of the instrument is described. Discussions of the tests and calibrations of component parts, and of the sources of errors also are included. There is also an analysis of the random and systematic errors effecting the overall accuracy in the determination of mixing ratio.

Report discussing the selection, specifications, and use of signal-light colors. It discusses the nature of the problem, and the mathematical representation, recognition, production, control, and use of such colors. The characteristics of different types of chromaticity boundaries and the purpose and effect of the requirement for similarity of chromaticity characteristics are given special consideration. The treatment is varied according to the intended use. The discussion of the control of colors and the section on the use of colors are nontechnical, whereas the section on the production of signal colors is designed for the colorimetrist who is faced with the problem of selecting limit filters or drafting a specification.

Report discussing the VLF, ELF propagation in the earth-ionosphere waveguide emphasizing the total field found by summing all modes which contribute appreciably. Solutions are given and calculations are made for a homogeneous isotropic ionosphere, a homogeneous ionosphere with a constant radial magnetic field imposed, and an ionosphere with a magnetic field of arbitrary dip angle.

Report discussing the relationship between quantum field theory and the the statistical theory of waves. Basic equations exist in the latter theory which correspond closely to the fundamental equations of the former theory; i.e., to the commutation relations and the Heisenberg equation of motion. A probability density function of waves is introduced here which corresponds to the probability amplitude function in quantum mechanics. The theory of the statistical Green's functions and their relationships to the expectation values of the physical variables is also extensively developed. It is found that there exists a one-to-one correspondence between the formalism of Green's functions presented here and that used in field theory.

Report of the refractive indices and densities of aqueous solutions of invert sugar at temperatures of 15, 20, 25, and 30º C, for concentrations up to about 82 percent of invert sugar (by weight). From the results, equations have been derived which relate the refractive index and percent of invert sugar (weight in air) at each temperature. Other equations relate the absolute density and percent of invert sugar (weight in vacuum) at each temperature. Five-decimal tables giving the refractive indices and densities of invert sugar solutions containing 1 to 85 percent of sugar are given for each percentage of invert sugar at the four temperatures.

Report discussing pressure measurements made with piston gages that are affected by gravity, temperature, pressure, and several other variables. For accurate determinations of pressure the calculations must take these variables into account. A general equation is developed and simplified procedures for calculating pressure are illustrated.

Report compiling the melting points of 70 metal oxides published prior to January 1963. Both the original melting point and the equivalent value based on the International Practical Temperature Scale of 1948 are presented. Included in the survey is information on pertinent experimental details such as the method of temperature measurement, purity, furnace type, and environmental conditions.