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 an analysis of seismic design provisions for buildings with three main objectives. As stated in the introduction, "The first objective was to assist the ATC in the preparation of its report. The second objective of the study was to augment the text of the published Provisions by providing a formal, consistent documentation of the text. The third objective was to provide alternate arrangements of the Provisions that would make them more readily usable by several categories of users" (p. 1). This report includes illustrations.

Report issued by the U.S. National Bureau of Standards discussing the use of metric units of measurement during construction. As stated in the scope, "this document outlines a selection of SI units, with multiples and sub-multiples, for general use in building design and construction" (p. 1). This report includes tables, and illustrations.

Graphical presentation of K-factors for eight isotherms, published data on the solid-vapor region, and a bibliography of approximately 450 references.

The need for thermodynamic functions of para hydrogen, especially in compressed liquid and dense fluid states, prompts the tabulation of these provisional properties, computed by approximate methods utilizing the new PVT data of these reports. Computation and preparation of the tables is discussed under the following: Approximate Computational Methods; Correlation Methods; Discussion of Errors; and Tables of Functions.

Description of 15 specific systems employing search-type selection principles.

Parameters determined by a least-squares method for the reduced Simon equation and for a new, empirical melting equation.

Summarizes progress to date on the formulation and numerical integration of systems of equations modeling general two-phase flows in a pipe.

Formulas, computer program, and illustrations for a great circle path at ionospheric heights.

Description of a computer program for searching chemical information on magnetic tape.

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

Graphical presentation of he three-phase region at and near the triple point of parahydrogen.

Design and performance of a new near-zone electric field-strength meter.

Integrated tables of pressure, volume, and temperature for the saturated liquid, from the triple point to the critical point, for oxygen, nitrogen, argon, and parahydrogen.

Technique for varying the coupling of power from far-infrared gas lasers and the design and construction of these lasers.

Tables and graphs constructed for electron probe x-ray spectrometers equipped with crystal changers and calibrated for LiF crystals in angstroms.

Design of a flashlamp-pumped dye laser capable of emitting light pulses 500 ns wide with a risetime of 300 ns.

Permanence and colorimetric properties of signal glass.

Descriptions of the principal changes in the calorimeter and bolometer unit from the WR28 models of a microwave serving as National Bureau of Standards standard for power measurements in the frequency range 50 to 75 GHz.

This paper presents the details to implement a WR15 attentuation and reflection coefficient magnitude measurement system.

The survey covers PVT, thermodynamic, thermal, transport, electrical radiative and mechanical properties.

Review of the progress in research, instrumentation, and service activities of the Spectrochemical Analysis Section from July 1970 to June 1971.

Abstract: The input impedance of a probe antenna exciting a transverse electromagnetic (TEM) transmission line cell is formulated by a variational approach. The formulation also utilizes the results from a previous work on the field distribution inside a TEM cell excited by a vertical electrical Hertzian dipole. The final result of imoedance is shown to consist of two distinct terms, which are respectively contributed by the ordinary rectangular waveguide and the gap perturbation. Numerical results for both the real and imaginary parts of the impedance are given. The resistive part is found to be proportional to the square of the probe length, and the reactive part largely capacitive.

Abstract: Automated time-difference measurements at the picosecond level have been achieved. The system described combines the best properties of three common methods: the single heterodyne measurement technique, the frequency divider, and the dual-mixer time-difference measurement system. This particular system combines two instrumentation standards, ANSI/IFEE-583 and ANSI/IEEE-488 with new, modular dual-mixer time-difference measurement hardware. The modular, standardized hardware together with the new measurement techniques permit the data acquisition modules to be contained in a standard CAMAC crate. This system, along with an external controller, is capable of measuring eiqht clocks, at the present time, and is expandable to twenty-four clocks with modified software and additional measurement modules. The system noise performance is described by a (rT = 3 x 10^-12 t^-1 for time difference measurements.