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.

From Introduction: "This Monograph describes methods and apparatus used at the National Bureau of Standards in connection with several series of investigations of heats of combustion of aircraft fuels [4, 5, 6, 7]."

Report issued by the Bureau of Standards over the thermophysical properties of hydrogen. Properties of hydrogen in varying states (gaseous, liquid, solid, etc.) are presented and discussed. This report includes tables, and illustrations.

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 discussing the philosophy of measurement assurance and the three levels of measurement assurance programs. The measurement assurance programs are outlined to show how control over the measurement process can be maintained and how the offset (or systematic error) from the unit of length maintained by the National Bureau of Standards ban be made negligible. This monograph is intended for those who need to know on a continuing basis the uncertainty of their gage block calibration procedure.

Report discussing discrete energy levels observed within certain crystals which are due to perturbations of energy levels of the free ion by an electrostatic field arising from the crystal lattice. The analytic procedures for determining the field from the charge configuration are given, and the resulting fields are classified according to their symmetry. After a general survey of group-theoretical ideas, the applicable groups are analyzed in detail, and characters appropriate for both integral and half-integral angular momenta of the free ion are tabulated. Text includes tabulations, equations, and matrices using Wigner and Racah coefficients.

Report of the near ultraviolet and visible emission spectrum of CH presented in the form of a spectrophotometric atlas. The spectrum was recorded photoelectrically from an acetylene-oxygen flame in the region 4900 to 3000 A by use of a high-resolution grating monochromator. Each of the lines in the CH spectrum is identified.

Report discussing important elements of thermometer design. Factors affecting the use of common types of liquid-in-glass thermometers are included together with tables of tolerances and reasonably attainable accuracies. The calculation of corrections for the temperature of the emergent stem is given in detail for various types of thermometers and conditions of use.

Report issued by the National Bureau of Standards over transporting discrete solids in partially-filled flow pipes. The methods and application of drainage flow are discussed. This report includes tables, illustrations, and photographs.

Report issued by the National Bureau of Standards over testing procedures used for solar domestic water heating systems. Testing methods are discussed. This report includes tables, illustrations, and photographs.

Report issued by the National Bureau of Standards over construction loads of multistory concrete buildings. Evaluations of the construction loads are discussed. This report includes illustrations, and photographs.

Technical paper issued by the Bureau of Standards over studies conducted on fire-clay bricks. The results of the studies are discussed. This paper includes tables, and illustrations.

Scientific paper issued by the Bureau of Mines over development of a dilatometer. The instrument is used in tests of thermal expansion. The methods are presented and discussed. This paper includes an illustration.

Pamphlet issued by the United States National Bureau of Standards discussing the Metric Conversion Act of 1975, the work of the U.S. Metric Board, and how government agencies are facilitating a switch to the metric system.

Report issued by the U.S. National Bureau of Standards discussing the construction of large electromagnetic cells. As stated in the introduction, "this instruction provides information and procedures necessary to fabricate a large transverse electromagnetic (TEM) cell to be used for experimental "electromagnetic interference" (EMI) evaluation studies" (p. 1). This report includes illustrations, and photographs.

Report issued by the U.S. National Bureau of Standards discussing results of a survey conducted on automatic mechanized indexing and data processing. As stated in the introduction, "it has concentrated on the major developments in and related demonstrations of automatic indexing potentialities. Examples are also given of indexes compiled by machine and of potentially related research efforts in such areas as natural language text searching, statistical association techniques used for search and retrieval, and proposed systems for concept processing" (p. 1). This report includes an illustration.

Major psychological findings and data in the field of the legibility of alphanumeric characters and other symbols.

Modification of an earlier program to remove restrictions in calculating the short or long great circle path.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

From introduction: Simple, precise expressions for lunar diameter, average brightness temperature, flux density, and shape factor are presented. An analysis of the relationship between these parameters and corresponding errors are included. For broadbeam (HPBW>d) antennas, results show that flux density and shape factor can be determined with errors less than 13 percent and 0.4 percent respectively at frequencies below 10 GHz. Extension of the analysis to higher frequencies is indicated.

From introduction: The feasibility of using a near-field array for electromagnetic susceptibility testing is studied. The basic objective is to control the element weightings such that a plane wave is generated within the test volume. The basic theory is developed for arbitrary array geometries, and numerical results are obtained for finite planar arrays. A general near-field array synthesis technique is developed, and the technique minimizes the mean square error in the test volume while constraining the array excitations. The constraint prevents large excitations and is useful in minimizing the fields outside the test volume. The basic idea looks promising, but some practical considerations, such as bandwidth and angular scanning limitations, require further theoretical and experimental investigation.

Abstract: A general theoretical approach is formulated to describe the complex electromagnetic environment of an N-element array. The theory reveals the element-to-element interactions and multiple reflections within the array. From the formulation, it is found that the interaction between an excited element and an open-circuited element can be viewed as the sum of terms describing all possible signal paths within the array environment which start from the radiating element and terminate on the element under observation. Within all paths except the most direct one, multiple reflections between subgroups of elements take place. The resulting solution is highly structured and recursive and is discussed in detail in the text. Illustrative examples are provided to facilitate understanding of these ideas.

Abstract: Laboratories accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) are identified along with the specific test methods for which they are accredited. The current status of existing accreditation programs is given for laboratories that test thermal insulation, freshly mixed concrete, carpet, wood burning stoves, paint, and personnel radiation dosimeters, and that provide acoustical testing services. Indexes are provided for searching the Directory for laboratories accredited in specific testing areas or for specific test methods.